Nuestros investigadores

Matías Antonio Ávila Zaragoza

Hepatología. Fundación para la Investigación Médica Aplicada
Índice H
46, (Scopus, 24/09/2019)

Publicaciones científicas más recientes (desde 2010)

Autores: Chen, C. B.; Nelson, L. J.; Ávila, Matías Antonio; et al.
Revista: CELLS
ISSN 2073-4409  Vol. 8  Nº 10  2019 
In recent years, the incidence of both liver and biliary tract cancer has increased. Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the two most common types of hepatic malignancies. Whereas HCC is the fifth most common malignant tumor in Western countries, the prevalence of CCA has taken an alarming increase from 0.3 to 2.1 cases per 100,000 people. The lack of specific biomarkers makes diagnosis very difficult in the early stages of this fatal cancer. Thus, the prognosis of CCA is dismal and surgery is the only effective treatment, whilst recurrence after resection is common. Even though chemotherapy and radiotherapy may prolong survival in patients with CCA, the 5-year survival rate is still very low-a significant global problem in clinical diagnosis and therapy. The mitogen-activated protein kinase (MAPK) pathway plays an important role in signal transduction by converting extracellular stimuli into a wide range of cellular responses including inflammatory response, stress response, differentiation, survival, and tumorigenesis. Dysregulation of the MAPK cascade involves key signaling components and phosphorylation events that play an important role in tumorigenesis. In this review, we discuss the pathophysiological role of MAPK, current therapeutic options, and the current situation of MAPK-targeted therapies in CCA.
Autores: Berasain, C; Ávila, Matías Antonio;
ISSN 1084-9521  2019  págs. 30193 - 30199
Autores: López, María Jesús; Martinez-Irujo, Juan J; et al.
ISSN 0167-4889  Vol. 1866  Nº 4  2019  págs. 673 - 685
Liver damage induces hepatic stellate cells (HSC) activation, characterised by a fibrogenic, proliferative and migratory phenotype. Activated HSC are mainly regulated by transforming growth factor ß 1 (TGFß1), which increases the production of extracellular matrix proteins (e.g. collagen-I) promoting the progression of hepatic fibrosis. AGAP2 (ArfGAP with GTPase domain, ankyrin repeat and PH domain 2) is a GTPase/GTP-activating protein involved in the actin remodelling system and receptor recycling. In the present work the role of AGAP2 in human HSC in response to TGFß1 was investigated. LX-2 HSC were transfected with AGAP2 siRNA and treated with TGFß1. AGAP2 knockdown prevented to some extent the proliferative and migratory TGFß1-induced capacities of LX-2 cells. An array focused on human fibrosis revealed that AGAP2 knockdown partially prevented TGFß1-mediated gene expression of the fibrogenic genes ACTA2, COL1A2, EDN1, INHBE, LOX, PDGFB, TGF¿12, while favored the expression of CXCR4, IL1A, MMP1, MMP3 and MMP9 genes. Furthermore, TGFß1 induced AGAP2 promoter activation and its protein expression in LX-2. Moreover, AGAP2 protein levels were significantly increased in liver samples from rats with thioacetamide-induced fibrosis. In addition, AGAP2 silencing affected TGFß1-receptor 2 (TGFR2) trafficking in U2OS cells, blocking its effective recycling to the membrane. AGAP2 silencing in LX-2 cells prevented the TGFß1-induced increase of collagen-I protein levels, while its overexpression enhanced collagen-I protein expression in the presence or absence of the cytokine. AGAP2 overexpression also increased focal adhesion kinase (FAK) phosphorylated levels in LX-2 cells. FAK and MEK1 inhibitors prevented the increase of collagen-I expression caused by TGFß1 in LX-2 overexpressing AGAP2. In summary, the present work shows for the first time, that AGAP2 is a potential new target involved in TGFß1 signalling, contributing to the progression of hepatic fibrosis.
Autores: Banales, J. M.; Iñarrairaegui, Mercedes; Arbelaiz, A.; et al.
ISSN 0270-9139  Vol. 70  Nº 2  2019  págs. 547 - 562
Early and differential diagnosis of intrahepatic cholangiocarcinoma (iCCA) and hepatocellular carcinoma (HCC) by noninvasive methods represents a current clinical challenge. The analysis of low-molecular-weight metabolites by new high-throughput techniques is a strategy for identifying biomarkers. Here, we have investigated whether serum metabolome can provide useful biomarkers in the diagnosis of iCCA and HCC and could discriminate iCCA from HCC. Because primary sclerosing cholangitis (PSC) is a risk factor for CCA, serum metabolic profiles of PSC and CCA have also been compared. The analysis of the levels of lipids and amino acids in the serum of patients with iCCA, HCC, and PSC and healthy individuals (n = 20/group) showed differential profiles. Several metabolites presented high diagnostic value for iCCA versus control, HCC versus control, and PSC versus control, with areas under the receiver operating characteristic curve (AUC) greater than those found in serum for the nonspecific tumor markers carbohydrate antigen 19-9 (CA 19-9) and alpha-fetoprotein (AFP), commonly used to help in the diagnosis of iCCA and HCC, respectively. The development of an algorithm combining glycine, aspartic acid, SM(42:3), and SM(43:2) permitted to accurately differentiate in the diagnosis of both types of tumors (biopsy-proven). The proposed model yielded 0.890 AUC, 75% sensitivity, and 90% specificity. Another algorithm by combination of PC(34:3) and histidine accurately permitted to differentiate PSC from iCCA, with an AUC of 0.990, 100% sensitivity, and 70% specificity. These results were validated in independent cohorts of 14-15 patients per group and compared with profiles found in patients with nonalcoholic fatty liver disease/nonalcoholic steatohepatitis. Conclusion: Specific changes in serum concentrations of certain metabolites are useful to differentiate iCCA from HCC or PSC, and could help in the early diagnosis of these diseases.
Autores: Santa María, Eva; Rodríguez, Carlos Manuel; Uriarte, Iker; et al.
ISSN 0270-9139  Vol. 69  Nº 4  2019  págs. 1632 - 1647
Intrahepatic accumulation of bile acids (BAs) causes hepatocellular injury. Upon liver damage, a potent protective response is mounted to restore the organ's function. Epidermal growth factor receptor (EGFR) signaling is essential for regeneration after most types of liver damage, including cholestatic injury. However, EGFR can be activated by a family of growth factors induced during liver injury and regeneration. We evaluated the role of the EGFR ligand, amphiregulin (AREG), during cholestatic liver injury and regulation of AREG expression by BAs. First, we demonstrated increased AREG levels in livers from patients with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC). In two murine models of cholestatic liver injury, bile duct ligation (BDL) and alpha-naphthyl-isothiocyanate (ANIT) gavage, hepatic AREG expression was markedly up-regulated. Importantly, Areg(-/-) mice showed aggravated liver injury after BDL and ANIT administration compared to Areg(+/+) mice. Recombinant AREG protected from ANIT and BDL-induced liver injury and reduced BA-triggered apoptosis in liver cells. Oral BA administration induced ileal and hepatic Areg expression, and, interestingly, cholestyramine feeding reduced postprandial Areg up-regulation in both tissues. Most interestingly, Areg(-/-) mice displayed high hepatic cholesterol 7 alpha-hydroxylase (CYP7A1) expression, reduced serum cholesterol, and high BA levels. Postprandial repression of Cyp7a1 was impaired in Areg(-/-) mice, and recombinant AREG down-regulated Cyp7a1 mRNA in hepatocytes. On the other hand, BAs promoted AREG gene expression and protein shedding in hepatocytes. This effect was mediated through the farnesoid X receptor (FXR), as demonstrated in Fxr(-/-) mice, and involved EGFR transactivation. Finally, we show that hepatic EGFR expression is indirectly induced by BA-FXR through activation of suppressor of cytokine signaling-3 (SOC3). Conclusion: AREG-EGFR signaling protects from cholestatic injury and participates in the physiological regulation of BA synthesis.
Autores: Berraondo, Pedro; Martini, P. G. V.; Ávila, Matías Antonio, (Autor de correspondencia); et al.
Revista: GUT
ISSN 0017-5749  Vol. 68  Nº 7  2019  págs. 1323 - 1330
Decades of intense research in molecular biology and biochemistry are fructifying in the emergence of therapeutic messenger RNAs (mRNA) as a new class of drugs. Synthetic mRNAs can be sequence optimised to improve translatability into proteins, as well as chemically modified to reduce immunogenicity and increase chemical stability using naturally occurring uridine modifications. These structural improvements, together with the development of safe and efficient vehicles that preserve mRNA integrity in circulation and allow targeted intracellular delivery, have paved the way for mRNA-based therapeutics. Indeed, mRNAs formulated into biodegradable lipid nanoparticles are currently being tested in preclinical and clinical studies for multiple diseases including cancer immunotherapy and vaccination for infectious diseases. An emerging application of mRNAs is the supplementation of proteins that are not expressed or are not functional in a regulated and tissue-specific manner. This so-called ' protein replacement therapy' could represent a solution for genetic metabolic diseases currently lacking effective treatments. Here we summarise this new class of drugs and discuss the preclinical evidence supporting the potential of liver-mediated mRNA therapy for three rare genetic conditions: methylmalonic acidaemia, acute intermittent porphyria and ornithine transcarbamylase deficiency.
Autores: Caruso, S. ; Llerena, S. ; Alvarez-Sola, G. ; et al.
ISSN 0270-9139  Vol. 69  Nº 2  2019  págs. 587 - 603
Epigenetic modifications such as DNA and histone methylation functionally cooperate in fostering tumor growth, including that of hepatocellular carcinoma (HCC). Pharmacological targeting of these mechanisms may open new therapeutic avenues. We aimed to determine the therapeutic efficacy and potential mechanism of action of our dual G9a histone-methyltransferase and DNA-methyltransferase 1 (DNMT1) inhibitor in human HCC cells and their crosstalk with fibrogenic cells. The expression of G9a and DNMT1, along with that of their molecular adaptor ubiquitin-like with PHD and RING finger domains-1 (UHRF1), was measured in human HCCs (n = 268), peritumoral tissues (n = 154), and HCC cell lines (n = 32). We evaluated the effect of individual and combined inhibition of G9a and DNMT1 on HCC cell growth by pharmacological and genetic approaches. The activity of our lead compound, CM-272, was examined in HCC cells under normoxia and hypoxia, human hepatic stellate cells and LX2 cells, and xenograft tumors formed by HCC or combined HCC+LX2 cells. We found a significant and correlative overexpression of G9a, DNMT1, and UHRF1 in HCCs in association with poor prognosis. Independent G9a and DNMT1 pharmacological targeting synergistically inhibited HCC cell growth. CM-272 potently reduced HCC and LX2 cells proliferation and quelled tumor growth, particularly in HCC+LX2 xenografts. Mechanistically, CM-272 inhibited the metabolic adaptation of HCC cells to hypoxia and induced a differentiated phenotype in HCC and fibrogenic cells. The expression of the metabolic tumor suppressor gene fructose-1,6-bisphosphatase (FBP1), epigenetically repressed in HCC, was restored by CM-272. Conclusion: Combined targeting of G9a/DNMT1 with compounds such as CM-272 is a promising strategy for HCC treatment. Our findings also underscore the potential of differentiation therapy in HCC.
Autores: Al-Abdulla, R.; Lozano, E.; Macías, R. I. R.; et al.
ISSN 0007-1188  Vol. 176  Nº 6  2019  págs. 787 - 800
Background and Purpose The expression of the human organic cation transporter-1 (hOCT1, gene SLC22A1) is reduced in hepatocellular carcinoma (HCC). The molecular bases of this reduction and its relationship with the poor response of HCC to sorafenib were investigated. Experimental Approach HCC transcriptomes from 366 samples available at TCGA were analysed. Alternative splicing was determined by RT-PCR. The role of miRNAs in SLC22A1 downregulation was investigated. Expression of Oct1 was measured in rodent HCC models (spontaneously generated in Fxr(-/-) mice and chemically-induced in rats). hOCT1 was overexpressed in human hepatoma cells (HuH7 and HepG2). Sorafenib and regorafenib uptake was determined by HPLC-MS/MS. Key Results hOCT1 overexpression enhanced sorafenib, but not regorafenib, quinine-inhibitable uptake by hepatoma cells. In rodent HCC, Oct1 was downregulated, which was accompanied by impaired sorafenib uptake. In mice with s.c.-implanted HCC, sorafenib inhibited the growth of hOCT1 overexpressing tumours. In human HCC, hOCT1 expression was inversely correlated with SLC22A1 promoter methylation, whereas demethylation with decitabine enhanced hOCT1 expression in hepatoma cells. Increased proportion of aberrant hOCT1 mRNA variants was found in HCC samples. In silico analysis identified six miRNAs as candidates to target hOCT1 mRNA. When overexpressed in HepG2 cells a significant hOCT1 mRNA decay was induced by hsa-miR-330 and hsa-miR-1468. Analysis of 39 paired tumour/adjacent samples from TCGA revealed that hsa-mir-330 was consistently upregulated inHCC. CONCLUSION AND IMPLICATIONS Impaired hOCT1 expression/ function in HCC, in part due to epigenetic modifications, plays an important role in the poor pharmacological response of this cancer to sorafenib.
Autores: Urtasun, R.; Elizalde, M.; et al.
ISSN 0305-1048  Vol. 47  Nº 7  2019  págs. 3450 - 3466
Genome instability is related to disease development and carcinogenesis. DNA lesions are caused by genotoxic compounds but also by the dysregulation of fundamental processes like transcription, DNA replication and mitosis. Recent evidence indicates that impaired expression of RNA-binding proteins results in mitotic aberrations and the formation of transcription-associated RNA-DNA hybrids (R-loops), events strongly associated with DNA injury. We identify the splicing regulator SLU7 as a key mediator of genome stability. SLU7 knockdown results in R-loops formation, DNA damage, cell-cycle arrest and severe mitotic derangements with loss of sister chromatid cohesion (SCC). We define a molecular pathway through which SLU7 keeps in check the generation of truncated forms of the splicing factor SRSF3 (SRp20) (SRSF3-TR). Behaving as dominant negative, or by gain-of-function, SRSF3-TR impair the correct splicing and expression of the splicing regulator SRSF1 (ASF/SF2) and the crucial SCC protein sororin. This unique function of SLU7 was found in cancer cells of different tissue origin and also in the normal mouse liver, demonstrating a conserved and fundamental role of SLU7 in the preservation of genome integrity. Therefore, the dowregulation of SLU7 and the alterations of this pathway that we observe in the cirrhotic liver could be involved in the process of hepatocarcinogenesis.
Autores: Argemie, J.; Latasa, María Ujué; Atkinson, S. R.; et al.
ISSN 2041-1723  Vol. 10  Nº 3126  2019 
Alcoholic hepatitis (AH) is a life-threatening condition characterized by profound hepatocellular dysfunction for which targeted treatments are urgently needed. Identification of molecular drivers is hampered by the lack of suitable animal models. By performing RNA sequencing in livers from patients with different phenotypes of alcohol-related liver disease (ALD), we show that development of AH is characterized by defective activity of liver-enriched transcription factors (LETFs). TGF beta 1 is a key upstream transcriptome regulator in AH and induces the use of HNF4 alpha P2 promoter in hepatocytes, which results in defective metabolic and synthetic functions. Gene polymorphisms in LETFs including HNF4 alpha are not associated with the development of AH. In contrast, epigenetic studies show that AH livers have profound changes in DNA methylation state and chromatin remodeling, affecting HNF4 alpha-dependent gene expression. We conclude that targeting TGF beta 1 and epigenetic drivers that modulate HNF4 alpha-dependent gene expression could be beneficial to improve hepatocellular function in patients with AH.
Autores: Lozano, E.; Macias, R. I. R.; Monte, M. J.; et al.
ISSN 0270-9139  Vol. 70  Nº 4  2019  págs. 1246 - 1261
Although the multi-tyrosine kinase inhibitor sorafenib is useful in the treatment of several cancers, cholangiocarcinoma (CCA) is refractory to this drug. Among other mechanisms of chemoresistance, impaired uptake through human organic cation transporter type 1 (hOCT1) (gene SLC22A1) has been suggested. Here we have investigated the events accounting for this phenotypic characteristic and have evaluated the interest of selective gene therapy strategies to overcome this limitation. Gene expression and DNA methylation of SLC22A1 were analyzed using intrahepatic (iCCA) and extrahepatic (eCCA) biopsies (Copenhagen and Salamanca cohorts; n = 132) and The Cancer Genome Atlas (TCGA)-CHOL (n = 36). Decreased hOCT1 mRNA correlated with hypermethylation status of the SLC22A1 promoter. Treatment of CCA cells with decitabine (demethylating agent) or butyrate (histone deacetylase inhibitor) restored hOCT1 expression and increased sorafenib uptake. MicroRNAs able to induce hOCT1 mRNA decay were analyzed in paired samples of TCGA-CHOL (n = 9) and Copenhagen (n = 57) cohorts. Consistent up-regulation in tumor tissue was found for miR-141 and miR-330. High proportion of aberrant hOCT1 mRNA splicing in CCA was also seen. Lentiviral-mediated transduction of eCCA (EGI-1 and TFK-1) and iCCA (HuCCT1) cells with hOCT1 enhanced sorafenib uptake and cytotoxic effects. In chemically induced CCA in rats, reduced rOct1 expression was accompanied by impaired sorafenib uptake. In xenograft models of eCCA cells implanted in mouse liver, poor response to sorafenib was observed. However, tumor growth was markedly reduced by cotreatment with sorafenib and adenoviral vectors encoding hOCT1 under the control of the BIRC5 promoter, a gene highly up-regulated in CCA. Conclusion: The reason for impaired hOCT1-mediated sorafenib uptake by CCA is multifactorial. Gene therapy capable of selectively inducing hOCT1 in tumor cells can be considered a potentially useful chemosensitization strategy to improve the response of CCA to sorafenib.
Autores: Di Maira, G. ; Piombanti, B.; Lombardo, A. ; et al.
ISSN 1590-8658  Vol. 51  Nº Supl. 1  2019  págs. E43 - E43
Autores: Colyn, L.; Alvarez-Sola, G.; Latasa, María Ujué; et al.
ISSN 0168-8278  Vol. 70  Nº Supl. 1  2019  págs. E27 - E28
Autores: Alvarez-Sole, G.; Uriarte, Iker; Latasa, María Ujué; et al.
ISSN 0925-4439  Vol. 1864  Nº 4  2018  págs. 1326 - 1334
The liver has an extraordinary regenerative capacity rapidly triggered upon injury or resection. This response is intrinsically adjusted in its initiation and termination, a property termed the "hepatostat". Several molecules have been involved in liver regeneration, and among them bile acids may play a central role. Intrahepatic levels of bile acids rapidly increase after resection. Through the activation of farnesoid X receptor (FXR), bile acids regulate their hepatic metabolism and also promote hepatocellular proliferation. FXR is also expressed in em terocytes, where bile acids stimulate the expression of fibroblast growth factor 15/19 (FGF15/19), which is released to the portal blood. Through the activation of FGFR4 on hepatocytes FGF15/19 regulates bile acids synthesis and finely tunes liver regeneration as part of the "hepatostat". Here we review the experimental evidences supporting the relevance of the FXR-FGF15/19-FGFR4 axis in liver regeneration and discuss potential therapeutic applications of PGF15/19 in the prevention of liver failure. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.
Autores: Shan, Z. ; Alvarez-Sola, G.; Uriarte, Iker; et al.
ISSN 2305-5839  Vol. 6  Nº 12  2018  págs. 257
Currently there are very few pharmacological options available to treat acute liver injury. Because its natural exposure to noxious stimuli the liver has developed a strong endogenous hepatoprotective capacity. Indeed, experimental evidence exposed a variety of endogenous hepatic and systemic responses naturally activated to protect the hepatic parenchyma and to foster liver regeneration, therefore preserving individual's survival. The fibroblast growth factor (FGF) family encompasses a range of polypeptides with important effects on cellular differentiation, growth survival and metabolic regulation in adult organisms. Among these FGFs, FGF19 and FGF21 are endocrine hormones that profoundly influence systemic metabolism but also exert important hepatoprotective activities. In this review, we revisit the biology of these factors and highlight their potential application for the clinical management of acute liver injury.
Autores: Arechederra, Maria; Ávila, Matías Antonio; et al.
ISSN 2415-1289  Vol. 3  Nº 84  2018 
Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. HCCs are molecularly heterogeneous tumors, and this complexity is to a great extent responsible for their poor response to conventional and targeted therapies. In this review we summarize recent evidence indicating that imbalanced expression of mRNA splicing factors can be a relevant source for this heterogeneity. We also discuss how these alterations may play a driver role in hepatocarcinogenesis by impinging on the general hallmarks of cancer. Considering the natural history of HCC, we focused on two pathogenic features that are characteristic of liver tumors: chromosomal instability and phenotypic de-differentiation. We highlight mechanisms connecting splicing derangement with these two processes and the enabling capacities acquired by liver cells along their neoplastic transformation. A thorough understanding of the alterations in the splicing machinery may also help to identify new HCC biomarkers and to design novel therapeutic strategies.
Autores: Desdouets, C., (Autor de correspondencia); Ávila, Matías Antonio;
ISSN 0016-5085  Vol. 154  Nº 5  2018  págs. 1229 - 1231
Autores: Berasain, C, (Autor de correspondencia); Ávila, Matías Antonio;
ISSN 1043-2760  Vol. 29  Nº 10  2018  págs. 668 - 670
The pleiotropic liver kinase B1 (LKB1) controls metabolism, cell polarity, and proliferation in an apparently cell-and context-specific manner. A recent study in Cell Reports has demonstrated that LKB1 is essential to maintain the characteristic quiescence of the liver and to secure genomic integrity during liver regeneration independently of AMPK.
Autores: Macias, R. I. R., (Autor de correspondencia); Banales, J. M.; Sangro, Bruno; et al.
ISSN 0925-4439  Vol. 1864  Nº 4  2018  págs. 1468 - 1477
The poor prognosis of cholangiocarcinoma (CCA) is in part due to late diagnosis, which is currently achieved by a combination of clinical, radiological and histological approaches. Available biomarkers determined in serum and biopsy samples to assist in CCA diagnosis are not sufficiently sensitive and specific. Therefore, the identification of new biomarkers, preferably those obtained by minimally invasive methods, such as liquid biopsy, is important. The development of innovative technologies has permitted to identify a significant number of genetic, epigenetic, proteomic and metabolomic CCA features with potential clinical usefulness in early diagnosis, prognosis or prediction of treatment response. Potential new candidates must be rigorously evaluated prior to entering routine clinical application. Unfortunately, to date, no such biomarker has achieved validation for these purposes. This review is an up-to-date of currently used biomarkers and the candidates with promising characteristics that could be included in the clinical practice in the next future. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.
Autores: Al-Aqil, F. A.; Monte, M. J. ; Peleteiro-Vigil, A.; et al.
ISSN 0925-4439  Vol. 1864  Nº 9  2018  págs. 2927 - 2937
At high doses, glucocorticoids (GC) have been associated with enhanced serum bile acids and liver injury. We have evaluated the effect of GC, in the absence of hepatotoxicity, on FXR/FGF91(Fgf15)/FGF21-mediated ileum-liver crosstalk. Rats and mice (wild type and Fxr(-/-), Fgf1.5(-/-) and int-Gr(-/-) strains; the latter with GC receptor (Gr) knockout selective for intestinal epithelial cells), were treated (i.p.) with dexamethasone, prednisolone or budesonide. In both species, high doses of GC caused hepatotoxicity. At a non-hepatotoxic dose, GC induced ileal Fgf15 down-regulation and liver Fgf21 up-regulation, without affecting Fxr expression. Fgf21 mRNA levels correlated with those of several genes involved in glucose and bile acid metabolism. Surprisingly, liver Cyp7a1 was not up-regulated. The expression of factors involved in transcriptional modulation by Fxr and Gr (p300, Drip205, CBP and Smrt) was not affected. Pxr target genes Cyp3a11 and Mrp2 were not up-regulated in liver or intestine. In contrast, the expression of some Ppar alpha target genes in liver (Fgf21, Cyp4a14 and Vanin-1) and intestine (Vanin-1 and Cyp3a11) was altered. In mice with experimental colitis, liver Fgf21 was up-regulated (4.4-fold). HepG2 cells transfection with FGF21 inhibited CYP7A1 promoter (prCYP7A1-Luc2). This was mimicked by pure human FGF21 protein or culture in medium previously conditioned by cells over-expressing FGF21. This response was not abolished by deletion of a putative response element for phosphorylated FGF21 effectors present in prCYP7A1. In conclusion, GC interfere with FXR/FGF19-mediated intestinal control of CYP7A1 expression by the liver and stimulate hepatic secretion of FGF21, which inhibits CYP7A1 promoter through an autocrine mechanism.
Autores: Fernandez-Ramos, D. ; Fernandez-Tussy, P.; Lopitz-Otsoa, F.; et al.
ISSN 2041-4889  Vol. 9  Nº 958  2018 
Glycine N-methyltransferase (GNMT) is the most abundant methyltransferase in the liver and a master regulator of the transmethylation flux. GNMT downregulation leads to loss of liver function progressing to fibrosis, cirrhosis, and hepatocellular carcinoma. Moreover, GNMT deficiency aggravates cholestasis-induced fibrogenesis. To date, little is known about the mechanisms underlying downregulation of GNMT levels in hepatic fibrosis and cirrhosis. On this basis, microRNAs are epigenetic regulatory elements that play important roles in liver pathology. In this work, we aim to study the regulation of GNMT by microRNAs during liver fibrosis and cirrhosis. Luciferase assay on the 3'UTR-Gnmt was used to confirm in silico analysis showing that GNMT is potentially targeted by the microRNA miR-873-5p. Correlation between GNMT and miR-873-5p in human cholestasis and cirrhosis together with miR-873-5p inhibition in vivo in different mouse models of liver cholestasis and fibrosis [bile duct ligation and Mdr2 (Abcb4)(-/-) mouse] were then assessed. The analysis of liver tissue from cirrhotic and cholestatic patients, as well as from the animal models, showed that miR-873-5p inversely correlated with the expression of GNMT. Importantly, high circulating miR-873-5p was also detected in cholestastic and cirrhotic patients. Preclinical studies with anti-miR-873-5p treatment in bile duct ligation and Mdr2(-/-) mice recovered GNMT levels in association with ameliorated inflammation and fibrosis mainly by counteracting hepatocyte apoptosis and cholangiocyte proliferation. In conclusion, miR-873-5p emerges as a novel marker for liver fibrosis, cholestasis, and cirrhosis and therapeutic approaches based on anti-miR-873-5p may be effective treatments for liver fibrosis and cholestatic liver disease.
Autores: Gerbes, A. , (Autor de correspondencia); Zoulim, F.; Tilg, H.; et al.
Revista: GUT
ISSN 0017-5749  Vol. 67  Nº 2  2018  págs. 380 - 388
Hepatocellular carcinoma (HCC) ranks number three among the most frequent causes of death from solid tumors worldwide. With obesity and fatty liver diseases as risk factors on the rise, HCC represents an ever increasing challenge. While there is still no curative treatment for most patients numerous novel drugs have been proposed, but most ultimately failed in phase III trials. This manuscript targets therapeutic advances and most burning issues. Expert key point summaries and urgent research agenda are provided regarding risk factors, including microbiota, need for prognostic and predictive biomarkers and the equivocal role of liver biopsy. Therapeutic topics highlighted are locoregional techniques, combination therapies and the potential of immunotherapy. Finally the manuscript provides a critical evaluation of novel targets and strategies for personalized treatment of HCC.
Autores: Jiang, L. ; Berraondo, Pedro; Jerico, D.; et al.
ISSN 1078-8956  Vol. 24  Nº 12  2018  págs. 1899 - 1909
Acute intermittent porphyria (AIP) results from haploinsufficiency of porphobilinogen deaminase (PBGD), the third enzyme in the heme biosynthesis pathway. Patients with AIP have neurovisceral attacks associated with increased hepatic heme demand. Phenobarbital-challenged mice with AIP recapitulate the biochemical and clinical characteristics of patients with AIP, including hepatic overproduction of the potentially neurotoxic porphyrin precursors. Here we show that intravenous administration of human PBGD (hPBGD) mRNA (encoded by the gene HMBS) encapsulated in lipid nanoparticles induces dose-dependent protein expression in mouse hepatocytes, rapidly normalizing urine porphyrin precursor excretion in ongoing attacks. Furthermore, hPBGD mRNA protected against mitochondrial dysfunction, hypertension, pain and motor impairment. Repeat dosing in AIP mice showed sustained efficacy and therapeutic improvement without evidence of hepatotoxicity. Finally, multiple administrations to nonhuman primates confirmed safety and translatability. These data provide proof-of-concept for systemic hPBGD mRNA as a potential therapy for AIP.
Autores: Santamaria, E. ; Rodríguez, Carlos Manuel; Uriarte, Iker; et al.
ISSN 0168-8278  Vol. 68  Nº Supl. 1  2018  págs. S74 - S74
Autores: Di Maira, G.; Piombanti, B.; Lombardo, A.; et al.
ISSN 0270-9139  Vol. 68  Nº Supl. 1  2018  págs. 1062A
Autores: Jiang, L.; Berraondo, Pedro; Guey, L.; et al.
ISSN 1096-7192  Vol. 123  Nº 2  2018  págs. S70 - S71
Autores: Argemí, José María; Kress, T. R.; et al.
ISSN 0016-5085  Vol. 152  Nº 5  2017  págs. 1203 - 1216.e15
BACKGROUND & AIMS: Liver regeneration after partial hepatectomy ( PH) increases the protein folding burden at the endoplasmic reticulum of remnant hepatocytes, resulting in induction of the unfolded protein response. We investigated the role of the core unfolded protein response transcription factor X-box binding protein 1 ( XBP1) in liver regeneration using genome-wide chromatin immunoprecipitation analysis. METHODS: We performed studies with C57Bl6-J ( control) and interleukin 6-knockout mice. Mice underwent PH or sham surgeries. In some mice, hepatic expression of XBP1 was knocked down by injection of adenoviral vectors encoding small hairpin RNAs against Xbp1 messenger RNA. Liver tissues were collected before surgery and at 6 and 48 hours after surgery and analyzed by chromatin immunoprecipitation followed by sequencing. We also performed functional analyses of HepG2 cells. RESULTS: Expression of XBP1 by hepatocytes increased immediately after PH ( priming phase of liver regeneration) in control mice, but this effect was delayed in interleukin 6-deficient mice. In mice with knockdown of XBP1, we observed of liver tissue persistent endoplasmic reticulum stress, defects in acute-phase response, and increased hepatocellular damage, compared with control mice. Chromatin immunoprecipitation analyses of liver tissue showed that at 6 hours after PH, liver XBP1 became bound to a large set of genes implicated in proteostasis, the acute-phase response, metabolism, and the DNA damage response ( DDR). At this time point, XBP1 bound the promoter of the signal transducer and activator of transcription 3 gene ( Stat3). Livers of XBP1-knockdown mice showed reduced expression of STAT3 and had lower levels of STAT3 phosphorylation at Ser727, a modification that promotes cell proliferation and the DDR. Regenerating livers from XBP1-knockdown mice expressed high levels of a marker of DNA double-strand breaks, phosphorylated histone 2A, member X ( H2AX), compared with control mice. The inhibition of XBP1 expression caused a reduced up-regulation of DDR messenger RNAs in regenerating hepatocytes. CONCLUSION: In livers of mice, we found that PH induces expression of XBP1, and that this activity requires interleukin 6. XBP1 expression regulates the unfolded protein response, acute-phase response, and DDR in hepatocytes. In regenerating livers, XBP1 deficiency leads to endoplasmic reticulum stress and DNA damage.
Autores: Álvarez-Sola, G.; Uriarte, Iker; Latasa, María Ujué; et al.
Revista: GUT
ISSN 0017-5749  Vol. 66  Nº 10  2017  págs. 1818 - 1828
Objective Fibroblast growth factor 15/19 (FGF15/19), an enterokine that regulates synthesis of hepatic bile acids (BA), has been proposed to influence fat metabolism. Without FGF15/19, mouse liver regeneration after partial hepatectomy (PH) is severely impaired. We studied the role of FGF15/19 in response to a high fat diet (HFD) and its regulation by saturated fatty acids. We developed a fusion molecule encompassing FGF19 and apolipoprotein A-I, termed Fibapo, and evaluated its pharmacological properties in fatty liver regeneration. Design Fgf15¿/¿ mice were fed a HFD. Liver fat and the expression of fat metabolism and endoplasmic reticulum (ER) stress-related genes were measured. Influence of palmitic acid (PA) on FGF15/19 expression was determined in mice and in human liver cell lines. In vivo half-life and biological activity of Fibapo and FGF19 were compared. Hepatoprotective and proregenerative activities of Fibapo were evaluated in obese db/db mice undergoing PH. Results Hepatosteatosis and ER stress were exacerbated in HFD-fed Fgf15¿/¿ mice. Hepatic expression of Ppar¿2 was elevated in Fgf15¿/¿ mice, being reversed by FGF19 treatment. PA induced FGF15/19 expression in mouse ileum and human liver cells, and FGF19 protected from PA-mediated ER stress and cytotoxicity. Fibapo reduced liver BA and lipid accumulation, inhibited ER stress and showed enhanced half-life. Fibapo provided increased db/db mice survival and improved regeneration upon PH. Conclusions FGF15/19 is essential for hepatic metabolic adaptation to dietary fat being a physiological regulator of Ppar¿2 expression. Perioperative administration of Fibapo improves fatty liver regeneration.
Autores: Mora, M I; Odriozola, L.; et al.
ISSN 1535-3893  Vol. 16  Nº 12  2017  págs. 4506 - 4514
Primary liver cancer (HCC) is recognized as the fifth most common neoplasm and the second leading cause of cancer death worldwide. Most risk factors are known, and the molecular pathogenesis has been widely studied in the past decade; however, the underlying molecular mechanisms remain to be unveiled, as they will facilitate the definition of novel biomarkers and clinical targets for more effective patient management. We utilize the B/D-HPP popular protein strategy. We report a list of popular proteins that have been highly cocited with the expression "liver cancer". Several enzymes highlight the known metabolic remodeling of liver cancer cells, four of which participate in one-carbon metabolism. This pathway is central to the maintenance of differentiated hepatocytes, as it is considered the connection between intermediate metabolism and epigenetic regulation. We designed a targeted selective reaction monitoring (SRM) method to follow up one-carbon metabolism adaptation in mouse HCC and in regenerating liver following exposure to CCl4. This method allows systematic monitoring of one-carbon metabolism and could prove useful in the follow-up of HCC and of chronically liver-diseased patients (cirrhosis) at risk of HCC. The SRM data are available via ProteomeXchange in PASSEL (PASS01060)
Autores: Xiang, J. Y.; Sun, H.; Su, L.; et al.
ISSN 0304-3835  Vol. 400  2017  págs. 117 - 126
Myocyte enhancer factor 2D (MEF2D) is involved in many aspects of cancer progression, including cell proliferation, invasion, and migration. However, little is known about the role of MEF2D in tumor angiogenesis. Using clinical specimens, colorectal cancer (CRC) cell lines and a mouse model in the present study, we found that MEF2D expression was positively correlated with CD31-positive micro-vascular density in CRC tissues. MEF2D promoted tumor angiogenesis in vitro and in vivo and induced the expression of proangiogenic cytokines in CRC cells. MEF2D was found to be a downstream effector of hypoxia-inducible factor (HIF)-1 alpha in the induction of tumor angiogenesis. HIF-1 alpha transactivates MEF2D expression by binding to the MEF2D gene promoter. These results demonstrate that the HIF-1 alpha/MEF2D axis can serve as a therapeutic target for the treatment of CRC. (C) 2017 Elsevier B.V. All rights reserved.
Autores: San José, Edurne; Agirre, X; et al.
ISSN 2041-1723  Vol. 8  2017  págs. 15424
The indisputable role of epigenetics in cancer and the fact that epigenetic alterations can be reversed have favoured development of epigenetic drugs. In this study, we design and synthesize potent novel, selective and reversible chemical probes that simultaneously inhibit the G9a and DNMTs methyltransferase activity. In vitro treatment of haematological neoplasia (acute myeloid leukaemia-AML, acute lymphoblastic leukaemia-ALL and diffuse large B-cell lymphoma-DLBCL) with the lead compound CM-272, inhibits cell proliferation and promotes apoptosis, inducing interferon-stimulated genes and immunogenic cell death. CM-272 significantly prolongs survival of AML, ALL and DLBCL xenogeneic models. Our results represent the discovery of first-in-class dual inhibitors of G9a/DNMTs and establish this chemical series as a promising therapeutic tool for unmet needs in haematological tumours.
Autores: Alvarez-Sola, G.; Uriarte, Iker; Latasa, María Ujué; et al.
ISSN 2041-4889  Vol. 8  Nº 10  2017  págs. e3083
The liver displays a remarkable regenerative capacity triggered upon tissue injury or resection. However, liver regeneration can be overwhelmed by excessive parenchymal destruction or diminished by pre-existing conditions hampering repair. Fibroblast growth factor 19 (FGF19, rodent FGF15) is an enterokine that regulates liver bile acid and lipid metabolism, and stimulates hepatocellular protein synthesis and proliferation. FGF19/15 is also important for liver regeneration after partial hepatectomy (PH). Therefore recombinant FGF19 would be an ideal molecule to stimulate liver regeneration, but its applicability may be curtailed by its short half-life. We developed a chimaeric molecule termed Fibapo in which FGF19 is covalently coupled to apolipoprotein A-I. Fibapo retains FGF19 biological activities but has significantly increased half-life and hepatotropism. Here we evaluated the pro-regenerative activity of Fibapo in two clinically relevant models where liver regeneration may be impaired: acetaminophen (APAP) poisoning, and PH in aged mice. The only approved therapy for APAP intoxication is N-acetylcysteine (NAC) and no drugs are available to stimulate liver regeneration. We demonstrate that Fibapo reduced liver injury and boosted regeneration in APAP-intoxicated mice. Fibapo improved survival of APAP-poisoned mice when given at later time points, when NAC is ineffective. Mechanistically, Fibapo accelerated recovery of hepatic glutathione levels, potentiated cell growth-related pathways and increased functional liver mass. When Fibapo was administered to old mice prior to PH, liver regeneration was markedly increased. The exacerbated injury developing in these mice upon PH was attenuated, and the hepatic biosynthetic capacity was enhanced. Fibapo reversed metabolic and molecular alterations that impede regeneration in aged livers. It reduced liver steatosis and downregulated p21 and hepatocyte nuclear factor 4 a (Hnf4a) levels, whereas it stimulated Foxm1b gene expression. Together our findings indicate that FGF19 variants retaining the metabolic and growth-promoting effects of this enterokine may be valuable for the stimulation of liver regeneration.
Autores: Alvarez-Sola, G.; Uriarte, Iker; Latasa, María Ujué; et al.
ISSN 0257-2753  Vol. 35  Nº 3  2017  págs. 158 - 165
Background: Advanced hepatocellular carcinoma (HCC) is a neoplastic disease with a very bad prognosis and increasing worldwide incidence. HCCs are resistant to conventional chemotherapy and the multikinase inhibitor sorafenib is the only agent that has shown some clinical efficacy. It is therefore important to identify key molecular mechanisms driving hepatocarcinogenesis for the development of more efficacious therapies. However, HCCs are heterogeneous tumors and different molecular subclasses have been characterized. This heterogeneity may underlie the poor performance of most of the targeted therapies so far tested in HCC patients. The fibroblast growth factor 15/19 (FGF15/19), FGF receptor 4 (FGFR4) and beta-Klotho (KLB) correceptor signaling system, a key regulator of bile acids (BA) synthesis and intermediary metabolism, is emerging as an important player in hepatocarcinogenesis. Key Messages: Aberrant signaling through the FGF15/19-FGFR4 pathway participates in the neoplastic behavior of HCC cells, promotes HCC development in mice and its overexpression has been characterized in a subset of HCC tumors from patients with poorer prognosis. Pharmacological interference with FGF15/19-FGFR4 signaling inhibits experimental hepatocarcinogenesis, and specific FGFR4 inhibitors are currently being tested in selected HCC patients with tumoral FGF19-FGFR4/KLB expression. Conclusions: Interference with FGF19-FGFR4 signaling represents a novel strategy in HCC therapy. Selection of candidate patients based on tumoral FGF19-FGFR4/KLB levels as biomarkers may result in increased efficacy of FGFR4-targeted drugs. Nevertheless, attention should be paid to the potential on target toxic effects of FGFR4 inhibitors due to the key role of this signaling system in BA metabolism. (C) 2017 S. Karger AG, Basel
Autores: Vilaseca, M. ; Garcia Caldero, H. ; Lafoz, E.; et al.
ISSN 0270-9139  Vol. 65  Nº 6  2017  págs. 2031 - 2044
In cirrhosis, increased intrahepatic vascular resistance (IHVR) is the primary factor for portal hypertension (PH) development. Hepatic stellate cells (HSCs) play a major role increasing IHVR because, when activated, they are contractile and promote fibrogenesis. Protease-activated receptors (PARs) can activate HSCs through thrombin and factor Xa, which are known PAR agonists, and cause microthrombosis in liver microcirculation. This study investigates the effects of the oral anticoagulant, rivaroxaban (RVXB), a direct antifactor Xa, on HSC phenotype, liver fibrosis (LF), liver microthrombosis, and PH in cirrhotic rats. Hepatic and systemic hemodynamic, nitric oxide (NO) bioavailability, LF, HSC activation, and microthrombosis were evaluated in CCl4 and thioacetamide-cirrhotic rats treated with RVXB (20 mg/kg/day) or its vehicle for 2 weeks. RVXB significantly decreased portal pressure (PP) in both models of cirrhosis without changes in portal blood flow, suggesting a reduction in IHVR. RVXB reduced oxidative stress, improved NO bioavailability, and ameliorated endothelial dysfunction. Rivaroxaban deactivated HSC, with decreased alpha-smooth muscle actin and mRNA expression of other HSC activation markers. Despite this marked improvement in HSC phenotype, no significant changes in LF were identified. RVXB markedly reduced fibrin deposition, suggesting reduced intrahepatic microthrombosis. Conclusion: RVXB decreases PP in two rat models of cirrhosis. This effect is mostly associated with decreased IHVR, enhanced NO bioavailability, HSC deactivation, and reduced intrahepatic microthrombosis. Our findings suggest that RVXB deserves further evaluation as a potential treatment for cirrhotic PH.
Autores: Bárcena, Sergio; Oyarzabal, Julen; Banales, J. M.; et al.
ISSN 0168-8278  Vol. 66  Nº 1  2017  págs. S76 - S77
Autores: Argemí, José María; Cabezas, J.; Massey, V. L.; et al.
ISSN 0270-9139  Vol. 66  Nº Supl. 1  2017  págs. 93A - 94A
Background: Alcoholic liver disease (ALD) is the main cause of cirrhosis worldwide and the main driver of health expenditure in hospitalized patients with liver disease in the US. The development of targeted therapies is hampered by a poor knowledge of the underlying mechanisms. It is unknown why some patients develop severe forms (i. e. alcoholic hepatitis -AH-) characterized by poor hepatocyte function. We hypothesize that global changes in the transcription factor activity may play a role in the development of severe forms. To test this hypothesis, we performed a functional analysis of RNAseq data from livers of patients with different ALD phenotypes compared to normal livers and cirrhosis. Methods: Liver biopsy specimens were collected from ALD patients in different stages of disease progression: early compensated ASH (N=12), non severe AH (N=11), severe AH non responders to steroids (N=9), severe AH responders (N=9) and liver explants from transplanted patients with severe AH (N=1l). Compensated HCV cirrhosis (n=10) and fragments from normal livers (N=10) were also studied. High-throughput RNA sequencing (RNA-Seq) was done. Unsupervised clustering (Bioconductor), gene ontology analysis (GSEA) and upstream regulator prediction (Ingenuity Pathway Analysis and Opossum) were performed. Results: Clustering analysis showed a specific transcriptome pattern across different ALD phenotypes. Major changes in ALD progression included the inhibition of hepatocyte biosynthetic pathways, drug metabolism, hepatocyte differentiation and the activation of cell proliferation, ECM deposition, inflammation and hypoxia. Importantly, AH mortality was associated with inhibition of cell responses to hypoxia and inflammation. Analysis of upstream regulators revealed profound transcription factor reprogramming Changes in the transcriptome along disease progression predicted a marked inhibition of nuclear factors responsible for hepatocyte differentiation (i. e. HNF4A, HNF1A and FOXA1), while factors implicated in cell damage and inflammation (i. e. NFATC2, STAT1 and NFKB1) were significantly activated Bioinformatic prediction showed an involvement of EGFR signaling in disease progression Studies in cultured hepatocytes demonstrated the inhibitory effect of EGFR activity on HNF4A expression and stability Conclusion: Progression to severe forms of ALD including AH is characterized by decreased activity of transcription factors implicated in hepatocyte differentiation. These results suggest that targeting transcription factors that maintain normal hepatocellular function represent a potential novel therapeutic strategy in these patients.
Autores: Fontanellas, Antonio; Ávila, Matías Antonio; Berraondo, Pedro;
ISSN 1462-3994  Vol. 18  2016  págs. e17
Acute intermittent porphyria (AIP) is an autosomal dominant metabolic disease caused by hepatic deficiency of hydroxymethylbilane synthase (HMBS), the third enzyme of the heme synthesis pathway. The dominant clinical feature is acute neurovisceral attack associated with high production of potentially neurotoxic porphyrin precursors due to increased hepatic heme consumption. Current Standard of Care is based on a down-regulation of hepatic heme synthesis using heme therapy. Recurrent hyper-activation of the hepatic heme synthesis pathway affects about 5% of patients and can be associated with neurological and metabolic manifestations and long-term complications including chronic kidney disease and increased risk of hepatocellular carcinoma. Prophylactic heme infusion is an effective strategy in some of these patients, but it induces tolerance and its frequent application may be associated with thromboembolic disease and hepatic siderosis. Orthotopic liver transplantation is the only curative treatment in patients with recurrent acute attacks. Emerging therapies including replacement enzyme therapy or gene therapies (HMBS-gene transfer and ALAS1-gene expression inhibition) are being developed to improve quality of life, reduce the significant morbidity associated with current therapies and prevent late complications such as hepatocellular cancer or kidney failure in HMBS mutation carriers with long-standing high production of noxious heme precursors. Herein, we provide a critical digest of the recent literature on the topic and a summary of recently developed approaches to AIP treatment and their clinical implications.
Autores: Berasain, C; Ávila, Matías Antonio;
ISSN 0270-9139  Vol. 63  Nº 2  2016  págs. 371 - 374
Autores: Berasain, C; Ávila, Matías Antonio;
ISSN 0270-9139  Vol. 64  Nº 2  2016  págs. 336 - 339
Autores: Simile, M. M. ; Latte, G.; Demartis, M. I.; et al.
ISSN 1949-2553  Vol. 7  Nº 31  2016  págs. 49194 - 49216
Previous studies showed that YAP1 is over-expressed in hepatocellular carcinoma (HCC). Here we observed higher expression of Yap1/Ctgf axis in dysplastic nodules and HCC chemically-induced in F344 rats, genetically susceptible to hepatocarcinogenesis, than in lesions induced in resistant BN rats. In BN rats, highest increase in Yap1-tyr357, p73 phosphorylation and Caspase 3 cleavage occurred. In human HCCs with poorer prognosis (<3 years survival after partial liver resection, HCCP), levels of YAP1, CTGF, 14-3-3, and TEAD proteins, and YAP1-14-3-3 and YAP1-TEAD complexes were higher than in HCCs with better outcome (>3 years survival; HCCB). In the latter, higher levels of phosphorylated YAP1-ser127, YAP1-tyr357 and p73, YAP1 ubiquitination, and Caspase 3 cleavage occurred. Expression of stemness markers NANOG, OCT-3/4, and CD133 were highest in HCCP and correlated with YAP1 and YAP1-TEAD levels. In HepG2, Huh7, and Hep3B cells, forced YAP1 over-expression led to stem cell markers expression and increased cell viability, whereas inhibition of YAP1 expression by specific siRNA, or transfection of mutant YAP1 which does not bind to TEAD, induced opposite alterations. These changes were associated, in Huh7 cells transfected with YAP1 or YAP1 siRNA, with stimulation or inhibition of cell migration and invasivity, respectively. Furthermore, transcriptome analysis showed that YAP1 transfection in Huh7 cells induces over-expression of genes involved in tumor stemness. In conclusion, Yap1 post-translational modifications favoring its ubiquitination and apoptosis characterize HCC with better prognosis, whereas conditions favoring the formation of YAP1-TEAD complexes are associated with aggressiveness and acquisition of stemness features by HCC cells.
Autores: Latasa, María Ujué; et al.
ISSN 0950-9232  Vol. 35  Nº 36  2016  págs. 4719 - 4729
Resisting death is a central hallmark of cancer cells. Tumors rely on a number of genetic mechanisms to avoid apoptosis, and alterations in mRNA alternative splicing are increasingly recognized to have a role in tumorigenesis. In this study, we identify the splicing regulator SLU7 as an essential factor for the preservation of hepatocellular carcinoma (HCC) cells viability. Compared with hepatocytes, SLU7 expression is reduced in HCC cells; however, further SLU7 depletion triggered autophagy-related cellular apoptosis in association with the overproduction of reactive oxygen species. Remarkably, these responses were not observed in primary human hepatocytes or in the well-differentiated HepaRG cell line. Mechanistically, we demonstrate that SLU7 binds the C13orf25 primary transcript in which the polycistronic oncomir miR-17-92 cluster is encompassed, and is necessary for its processing and expression. SLU7 knockdown altered the splicing of the C13orf25 primary transcript, and markedly reduced the expression of its miR-17, miR-20 and miR-92a constituents. This led to the upregulation of CDKN1A (P21) and BCL2L11 (BIM) expression, two bona fide targets of the miR-17-92 cluster and recognized mediators of its pro-survival and tumorigenic activity. Interestingly, altered splicing of miR-17-92 and downregulation of miR-17 and miR-20 were not observed upon SLU7 knockdown in non-transformed hepatocytes, but was found in other (HeLa, H358) but not in all (Caco2) non-hepatic tumor cells. The functional relevance of miR-17-92 dysregulation upon SLU7 knockdown was established when oxidative stress, autophagy and apoptosis were reversed by co-transfection of HCC cells with a miR-17 mimic. Together, these findings indicate that SLU7 is co-opted by HCC cells and other tumor cell types to maintain survival, and identify this splicing regulator as a new determinant for the expression of the oncogenic miR-17-92 cluster. This novel mechanism may be exploited for the development of antitumoral strategies in cancers displaying such SLU7-miR-17-92 crosstalk.
Autores: Alvarez Sola, G. ; Uriarte, Iker; Latasa, María Ujué; et al.
ISSN 0168-8278  Vol. 64  Nº Supl. 2  2016  págs. S184
Autores: Vilaseca, M.; Lopez Sanjurjo, C. I.; Lafoz, E.; et al.
ISSN 0168-8278  Vol. 64  Nº Supl. 2  2016  págs. S710 - S711
Autores: Romero, M. R. ; Al Aqil, F. ; Monte, M. J.; et al.
ISSN 0168-8278  Vol. 64  Nº Supl. 2  2016  págs. S178 - S179
Autores: Argemí, José María; Kress, T.; et al.
ISSN 0270-9139  Vol. 64  Nº Supl. 1  2016  págs. 266A
Autores: Berasain, C; Ávila, Matías Antonio;
ISSN 1420-682X  Vol. 72  Nº 20  2015  págs. 3831 - 3851
The liver is a highly differentiated organ with a central role in metabolism, detoxification and systemic homeostasis. To perform its multiple tasks, liver parenchymal cells, the hepatocytes, express a large complement of enabling genes defining their complex phenotype. This phenotype is progressively acquired during fetal development and needs to be maintained in adulthood to guarantee the individual's survival. Upon injury or loss of functional mass, the liver displays an extraordinary regenerative response, mainly based on the proliferation of hepatocytes which otherwise are long-lived quiescent cells. Increasing observations suggest that loss of hepatocellular differentiation and quiescence underlie liver malfunction in chronic liver disease and pave the way for hepatocellular carcinoma development. Here, we briefly review the essential mechanisms leading to the acquisition of liver maturity. We also identify the key molecular factors involved in the preservation of hepatocellular homeostasis and finally discuss potential strategies to preserve liver identity and function.
Autores: Ávila, Matías Antonio; Berasain, C;
ISSN 0270-9139  Vol. 61  Nº 5  2015  págs. 1755 - 1757
Autores: García, Oihane; Latasa, María Ujué; Carotti, S.; et al.
ISSN 0270-9139  Vol. 62  Nº 1  2015  págs. 166 - 178
Matrix metalloproteinases (MMPs) participate in tissue repair after acute injury, but also participate in cancer by promoting a protumorigenic microenvironment. Previously, we reported on a key role for MMP10 in mouse liver regeneration. Herein, we investigated MMP10 expression and function in human hepatocellular carcinoma (HCC) and diethylnitrosamine (DEN)-induced mouse hepatocarcinogenesis. MMP10 was induced in human and murine HCC tissues and cells. MMP10-deficient mice showed less HCC incidence, smaller histological lesions, reduced tumor vascularization, and less lung metastases. Importantly, expression of the protumorigenic, C-X-C chemokine receptor-4 (CXCR4), was reduced in DEN-induced MMP10-deficient mice livers. Human HCC cells stably expressing MMP10 had increased CXCR4 expression and migratory capacity. Pharmacological inhibition of CXCR4 significantly reduced MMP10-stimulated HCC cell migration. Furthermore, MMP10 expression in HCC cells was induced by hypoxia and the CXCR4 ligand, stromal-derived factor-1 (SDF1), through the extracellular signal-regulated kinase 1/2 pathway, involving an activator protein 1 site in MMP10 gene promoter. CONCLUSION: MMP10 contributes to HCC development, participating in tumor angiogenesis, growth, and dissemination. We identified a new reciprocal crosstalk between MMP10 and the CXCR4/SDF1 axis contributing to HCC progression and metastasis. To our knowledge, this is the first report addressing the role of a MMP in hepatocarcinogenesis in the corresponding genetic mouse model.
Autores: Uriarte, Iker; Latasa, María Ujué; Carotti, S.; et al.
ISSN 0020-7136  Vol. 136  Nº 10  2015  págs. 2469 - 2475
Fibroblast growth factor 15 (FGF15), FGF19 in humans, is a gut-derived hormone and a key regulator of bile acids and carbohydrate metabolism. FGF15 also participates in liver regeneration after partial hepatectomy inducing hepatocellular proliferation. FGF19 is overexpressed in a significant proportion of human hepatocellular carcinomas (HCC), and activation of its receptor FGFR4 promotes HCC cell growth. Here we addressed for the first time the role of endogenous Fgf15 in hepatocarcinogenesis. Fgf15(+/+) and Fgf15(-/-) mice were subjected to a clinically relevant model of liver inflammation and fibrosis-associated carcinogenesis. Fgf15(-/-) mice showed less and smaller tumors, and histological neoplastic lesions were also smaller than in Fgf15(+/+) animals. Importantly, ileal Fgf15 mRNA expression was enhanced in mice undergoing carcinogenesis, but at variance with human HCC it was not detected in liver or HCC tissues, while circulating FGF15 protein was clearly upregulated. Hepatocellular proliferation was also reduced in Fgf15(-/-) mice, which also expressed lower levels of the HCC marker alpha-fetoprotein (AFP). Interestingly, lack of FGF15 resulted in attenuated fibrogenesis. However, in vitro experiments showed that liver fibrogenic stellate cells were not direct targets for FGF15/FGF19. Conversely we demonstrate that FGF15/FGF19 induces the expression of the pro-fibrogenic and pro-tumorigenic connective tissue growth factor (CTGF) in hepatocytes. These findings suggest the existence of an FGF15-triggered CTGF-mediated paracrine action on stellate cells, and an amplification mechanism for the hepatocarcinogenic effects of FGF15 via CTGF production. In summary, our observations indicate that ileal FGF15 may contribute to HCC development in a context of chronic liver injury and fibrosis. What's new? Fibroblast growth factor-19 (FGF19), in rodents called FGF15, is a gut-derived hormone recently implicated as a driver gene in liver carcinogenesis. Here, the authors show that Fgf15(-/-) mice develop less hepatocellular carcinoma and less liver fibrosis as compared to Fgf15(+/+) littermates, underscoring the important role of the factor in liver damage and cancer development. Interestingly, Fgf15 expression is not detected in injured liver or carcinoma tissue, but is upregulated in the ileum and blood, pointing to a new gut-liver axis involved in hepatocarcinogenesis.
Autores: García, Oihane; Latasa, María Ujué; Carotti, S.; et al.
ISSN 0270-9139  Vol. 62  Nº 1  2015  págs. 166 - 178
Matrix metalloproteinases (MMPs) participate in tissue repair after acute injury, but also participate in cancer by promoting a protumorigenic microenvironment. Previously, we reported on a key role for MMP10 in mouse liver regeneration. Herein, we investigated MMP10 expression and function in human hepatocellular carcinoma (HCC) and diethylnitrosamine (DEN)-induced mouse hepatocarcinogenesis. MMP10 was induced in human and murine HCC tissues and cells. MMP10-deficient mice showed less HCC incidence, smaller histological lesions, reduced tumor vascularization, and less lung metastases. Importantly, expression of the protumorigenic, C-X-C chemokine receptor-4 (CXCR4), was reduced in DEN-induced MMP10-deficient mice livers. Human HCC cells stably expressing MMP10 had increased CXCR4 expression and migratory capacity. Pharmacological inhibition of CXCR4 significantly reduced MMP10-stimulated HCC cell migration. Furthermore, MMP10 expression in HCC cells was induced by hypoxia and the CXCR4 ligand, stromal-derived factor-1 (SDF1), through the extracellular signal-regulated kinase 1/2 pathway, involving an activator protein 1 site in MMP10 gene promoter. Conclusion: MMP10 contributes to HCC development, participating in tumor angiogenesis, growth, and dissemination. We identified a new reciprocal crosstalk between MMP10 and the CXCR4/SDF1 axis contributing to HCC progression and metastasis. To our knowledge, this is the first report addressing the role of a MMP in hepatocarcinogenesis in the corresponding genetic mouse model. (Hepatology 2015;62:166-178)
Autores: Iñarrairaegui, Mercedes; Páramo, José Antonio; et al.
ISSN 1478-3223  Vol. 35  Nº 5  2015  págs. 1590 - 96
BACKGROUND & AIMS: Radioembolization may rarely induce liver disease resulting in a syndrome that is similar to veno-occlusive disease complicating bone marrow transplantation where inflammation, endothelial cell activation and thrombosis are likely involved. We hypothesized that similar mechanisms could be implicated in radioembolization-induced liver disease (REILD). Moreover, lobar radioembolization may induce hypertrophy of the non-treated hemiliver most probably by inducing liver regeneration. METHODS: In patients with hepatocellular carcinoma, we prospectively studied serum levels of markers of liver regeneration, oxidative stress, pro-inflammatory pathways, endothelial activation and coagulation parameters over 2 months after radioembolization. RESULTS: Although REILD did not occur among 14 treated patients, a decrease in effective liver blood flow was observed. Radioembolization was followed by a persistent increase in pro-inflammatory (interleukin 6 and 8) and oxidative stress (malondyaldehide) markers, an induction of endothelial injury markers (vW factor and PAI-1) and an activation of the coagulation cascade (factor VIII, PAI-1, D-Dimer) as well as a significant increase in factors related to liver regeneration (FGF-19 and HGF). CONCLUSION: Radioembolization activates liver regeneration, produces oxidative stress, activates inflammatory cytokines and induces endothelial injury with partial activation of the coagulation cascade. These findings may have implicati
Autores: San José, Edurne; Agirre, X; et al.
ISSN 0390-6078  Vol. 100  2015  págs. 27
Autores: García, Oihane; Latasa, María Ujué; Carotti, S.; et al.
ISSN 0168-8278  Vol. 62  Nº Supl. 2  2015  págs. S242
Autores: San José, Edurne; Agirre, X; Rabal, O.; et al.
ISSN 0390-6078  Vol. 100  Nº Supl. 4  2015  págs. 60 - 61
Autores: Berasain, C; Ávila, Matías Antonio;
ISSN 0944-1174  Vol. 49  Nº 1  2014  págs. 9 - 23
The liver displays an outstanding wound healing and regenerative capacity unmatched by any other organ. This reparative response is governed by a complex network of inflammatory mediators, growth factors and metabolites that are set in motion in response to hepatocellular injury. However, when liver injury is chronic, these regenerative mechanisms become dysregulated, facilitating the accumulation of genetic alterations leading to unrestrained cell proliferation and the development of hepatocellular carcinoma (HCC). The epidermal growth factor receptor (EGFR or ErbB1) signaling system has been identified as a key player in all stages of the liver response to injury, from early inflammation and hepatocellular proliferation to fibrogenesis and neoplastic transformation. The EGFR system engages in extensive crosstalk with other signaling pathways, acting as a true signaling hub for other growth factors, cytokines and inflammatory mediators. Here, we briefly review essential aspects of the biology of the EGFR, the other ErbB receptors, and their ligands in liver injury, regeneration and HCC development. Some aspects of the preclinical and clinical experience with EGFR therapeutic targeting in HCC are also discussed.
Autores: Berasain, C; Ávila, Matías Antonio;
ISSN 0270-9139  Vol. 59  Nº 6  2014  págs. 2080 - 2082
Autores: Latasa, María Ujué; et al.
ISSN 0021-9738  Vol. 124  Nº 7  2014  págs. 2909-2920
A precise equilibrium between cellular differentiation and proliferation is fundamental for tissue homeostasis. Maintaining this balance is particularly important for the liver, a highly differentiated organ with systemic metabolic functions that is endowed with unparalleled regenerative potential. Carcinogenesis in the liver develops as the result of hepatocellular de-differentiation and uncontrolled proliferation. Here, we identified SLU7, which encodes a pre-mRNA splicing regulator that is inhibited in hepatocarcinoma, as a pivotal gene for hepatocellular homeostasis. SLU7 knockdown in human liver cells and mouse liver resulted in profound changes in pre-mRNA splicing and gene expression, leading to impaired glucose and lipid metabolism, refractoriness to key metabolic hormones, and reversion to a fetal-like gene expression pattern. Additionally, loss of SLU7 also increased hepatocellular proliferation and induced a switch to a tumor-like glycolytic phenotype. Slu7 governed the splicing and/or expression of multiple genes essential for hepatocellular differentiation, including serine/arginine-rich splicing factor 3 (Srsf3) and hepatocyte nuclear factor 4¿ (Hnf4¿), and was critical for cAMP-regulated gene transcription. Together, out data indicate that SLU7 is central regulator of hepatocyte identity and quiescence.
Autores: Berasain, C; Ávila, Matías Antonio;
Título: Amphiregulin
ISSN 1084-9521  2014  págs. 31 - 41
Amphiregulin (AREG) is a ligand of the epidermal growth factor receptor (EGFR), a widely expressed transmembrane tyrosine kinase. AREG is synthesized as a membrane-anchored precursor protein that can engage in juxtacrine signaling on adjacent cells. Alternatively, after proteolytic processing by cell membrane proteases, mainly TACE/ADAM17, AREG is secreted and behaves as an autocrine or paracrine factor. AREG gene expression and release is induced by a plethora of stimuli including inflammatory lipids, cytokines, hormones, growth factors and xenobiotics. Through EGFR binding AREG activates major intracellular signaling cascades governing cell survival, proliferation and motility. Physiologically, AREG plays an important role in the development and maturation of mammary glands, bone tissue and oocytes. Chronic elevation of AREG expression is increasingly associated with different pathological conditions, mostly of inflammatory and/or neoplastic nature. Here we review the essential aspects of AREG structure, function and regulation, discuss the basis for its differential role within the EGFR family of ligands, and identify emerging aspects in AREG research with translational potential.
Autores: García, Oihane; Carotti, S.; Latasa, María Ujué; et al.
ISSN 0168-8278  Vol. 60  Nº 1  2014  págs. S87 - S87
Autores: Uriarte, Iker; Latasa, María Ujué; Fernández de Barrena, Sara Elena; et al.
ISSN 0168-8278  Vol. 60  Nº 1  2014  págs. S40 - S40
Autores: Berasain, C; Ávila, Matías Antonio;
ISSN 0270-9139  Vol. 58  Nº 3  2013  págs. 853 - 855
Autores: Uriarte, Iker; Fernandez-Barrena, M. G.; Monte, M. J.; et al.
Revista: GUT
ISSN 0017-5749  Vol. 62  Nº 6  2013  págs. 899 - 910
Objective Cholestasis is associated with increased liver injury and morbidity after partial hepatectomy (PH), yet bile acids (BAs) are emerging as important mediators of liver regeneration. Fibroblast growth factor 15 (Fgf15, human FGF19) is a BA-induced ileum-derived enterokine that governs BA metabolism. We evaluated the relevance of Fgf15 in the preservation of BA homeostasis after PH and its potential role in the regenerative process. Design Liver regeneration after PH was studied in Fgf15(-/-) and Fgf15(+/+) mice. The effects of the BA sequestrant cholestyramine and adenovirally delivered Fgf15 were examined in this model. The role of Fgf15 in BA-induced liver growth was tested in Fgf15-/- mice upon cholic acid (CA) feeding. The direct mitogenic effect of Fgf15 was evaluated in cultured mouse hepatocytes and cholangiocytes. Results Fgf15(-/-) mice showed marked liver injury and mortality after PH accompanied by persistently elevated intrahepatic BA levels. Cholestyramine feeding and adenovirally delivered Fgf15 reduced BA levels and significantly prevented this lethal outcome. Fgf15 also reduced mortality after extensive hepatectomy in Fgf15(+/+) animals. Liver growth elicited by CA feeding was significantly diminished in Fgf15(-/-) mice. Proliferation of hepatocytes and cholangiocytes was also noticeably reduced in CA-fed Fgf15(-/-) mice. Fgf15 induced intracellular signalling and proliferation of cultured hepatocytes and cholangiocytes. Conclusions Fgf15 is necessary to maintain BA homeostasis and prevent liver injury during liver regeneration. Moreover, Fgf15 is an essential mediator of the liver growth-promoting effects of BA. Preoperative administration of this enterokine to patients undergoing liver resection might be useful to reduce damage and foster regeneration.
Autores: García, Oihane; Carotti, S.; Latasa, María Ujué; et al.
ISSN 1478-3223  Vol. 34  Nº 7  2013  págs. e257 - e270
Background & Aims Upon tissue injury, the liver mounts a potent reparative and regenerative response. A role for proteases, including serine and matrix metalloproteinases ( MMPs), in this process is increasingly recognized. We have evaluated the expression and function of MMP10 (stromelysin-2) in liver wound healing and regeneration. Methods The hepatic expression of MMP10 was examined in two murine models: liver regeneration after two-thirds partial hepatectomy (PH) and bile duct ligation (BDL). MMP10 was detected in liver tissues by qPCR, western blotting and immunohistochemistry. The effect of growth factors and toll-like receptor 4 (TLR4) agonists on MMP10 expression was studied in cultured parenchymal and biliary epithelial cells and macrophages respectively. The role of MMP10 was evaluated by comparing the response of Mmp10+/+ and Mmp10¿/¿ mice to PH and BDL. The intrahepatic turnover of the extracellular matrix proteins fibrin (ogen) and fibronectin was examined. Results MMP10 mRNA was readily induced after PH and BDL. MMP10 protein was detected in hepatocytes, cholangiocytes and macrophages. In cultured liver epithelial cells, MMP10 expression was additively induced by transforming growth factor-ß and epidermal growth factor receptor ligands. TLR4 ligands also stimulated MMP10 expression in macrophages. Lack of MMP10 resulted in increased liver injury upon PH and BDL. Resolution of necrotic areas was impaired, and Mmp10¿/¿ mice showed increased fibrogenesis and defective turnover of fibrin (ogen) and fibronectin. Conclusions MMP10 expression is induced during mouse liver injury and participates in the hepatic wound healing response. The profibrinolytic activity of MMP10 may be essential in this novel hepatoprotective role.
Autores: Álvarez, Laura; et al.
ISSN 0016-5085  Vol. 144  Nº 4  2013  págs. 818 - 828
Background& Aims: ¿1-Antichymotrypsin (¿1-ACT), a member of the serpin family (SERPINA3), is an acute-phase protein secreted by hepatocytes in response to cytokines such as oncostatin M. ¿1-ACT is a protease inhibitor thought to limit tissue damage produced by excessive inflammation-associated proteolysis. However, ¿1-ACT also is detected in the nuclei of cells, where its activities are unknown. Expression of ¿1-ACT is down-regulated in human hepatocellular carcinoma (HCC) tissues and cells; we examined its roles in liver regeneration and HCC proliferation. Methods: We measured levels of ¿1-ACT messenger RNA in human HCC samples and healthy liver tissue. We reduced levels of ¿1-ACT using targeted RNA interference in human HCC (HepG2) and mouse hepatocyte (AML12) cell lines, and overexpressed ¿1-ACT from lentiviral vectors in Huh7 (HCC) cells and adeno-associated viral vectors in livers of mice. We assessed proliferation, differentiation, and chromatin compaction in cultured cells, and liver regeneration and tumor formation in mice. Results: Reducing levels of ¿1-ACT promoted proliferation of HCC cells in vitro. Oncostatin M up-regulated ¿1-ACT expression and nuclear translocation, which inhibited HCC cell proliferation and activated differentiation of mouse hepatocytes. We identified amino acids required for ¿1-ACT nuclear localization, and found that ¿1-ACT inhibits cell-cycle progression and anchorage-independent proliferation of HCC cells. HCC cells that overexpressed ¿1-ACT formed smaller tumors in mice than HCC cells that did not express the protein. ¿1-ACT was observed to self-associate and polymerize in the nuclei of cells; nuclear ¿1-ACT strongly bound chromatin to promote a condensed state that could prevent cell proliferation. Conclusions: ¿1-ACT localizes to the nuclei of hepatic cells to control chromatin condensation and proliferation. Overexpression of ¿1-ACT slows the growth of HCC xenograft tumors in nude mice.
Autores: García, Oihane; Latasa, María Ujué; et al.
ISSN 0168-8278  Vol. 58  2013  págs. S126 - S126
Autores: Berasain, C; Garcia-Irigoyen, O.; Latasa, María Ujué; et al.
ISSN 0257-2753  Vol. 30  Nº 5  2012  págs. 524-531
Background/Aims: Hepatocellular carcinoma (HCC) is a chemoresistant tumor strongly associated with chronic hepatitis. Identification of molecular links connecting inflammation with cell growth/survival, and characterization of pro-tumorigenic intracellular pathways is therefore of therapeutic interest. The epidermal growth factor receptor (EGFR) signaling system stands at a crossroad between inflammatory signals and intracellular pathways associated with hepatocarcinogenesis. We investigated the regulation and activity of different components of the EGFR system, including the EGFR ligand amphiregulin (AR) and its sheddase ADAM17, and the modulation of intracellular EGFR signaling by a novel mechanism involving protein methylation. Methods: ADAM17 protein expression was examined in models of liver injury and carcinogenesis. Crosstalk between tumor necrosis factor (TNF)-alpha, AR and EGFR signaling was evaluated in human HCC cells and mouse hepatocytes. Modulation of EGFR signaling and biological responses by methylation reactions was evaluated in AML12 mouse hepatocytes. Results: ADAM17 was upregulated in liver injury and hepatocarcinogenesis. TNF-alpha triggered AR shedding and EGFR transactivation in HCC cells. AR was necessary for TNF-alpha activation of ERK1/2 and Akt signaling in hepatocytes. Inhibition of methylation reactions increased the ERK1/2 signal amplitude triggered by AR/EGFR and reduced DNA synthesis in AML12 cells. Conclusions: Increased ADAM17 in preneoplastic liver injury further supports its implication in hepatocarcinogenesis. AR release and EGFR transactivation by TNF-alpha constitutes a novel link between inflammatory signals and pro-tumorigenic mechanisms in liver cells. Finally, the identification of a new mechanism controlling growth factor signaling, and biological responses, involving methylation reactions within the RAS/RAF/MEK/ERK pathway, exposes a new target for antineoplastic intervention. Copyright (C) 2012 S. Karger AG, Basel
Autores: Vespasiani-Gentilucci, U; Carotti, S; Onetti-Muda, A; et al.
ISSN 0893-3952  Vol. 25  Nº 4  2012  págs. 576 - 589
Notwithstanding numerous evidences implicating toll-like receptor-4 (TLR4) in the pathogenesis of chronic hepatitis C virus (HCV) infection, the localization and level of TLR4 expression in the liver of patients with hepatitis C have never been investigated. We aimed to evaluate, by means of immunohistochemistry and real-time PCR (rt-PCR), hepatic TLR4 expression in patients with chronic HCV infection. Fifty patients who had undergone liver biopsy and 11 patients transplanted because of chronic HCV infection, and 12 controls free of liver disease, were included in the study. Each case was analyzed by immunohistochemistry for TLR4, se smooth muscle actin and cytokeratin-7 (CK-7), and a subgroup of patients and all controls by rt-PCR for TLR4. Immunohistochemistry for a-smooth muscle actin was used to derive a score of activation of hepatic stellate cells and portal/septal myofibroblasts, while immunohistochemistry for CK-7 was used to evaluate and count hepatic progenitor cells, interlobular bile ducts and intermediate hepatocytes. In patients, the parenchymal elements responsible for the highest TLR4 level of expression were hepatic progenitor cells and biliary epithelial cells of interlobular bile ducts. Double-labeling experiments between anti-TLR4 and anti-CK7, anti-CD133, anti-CD44, anti-neural cell adhesion molecule, anti-epithelial cell adhesion molecule and anti-sex determining region Y-box 9, confirmed these findings. TLR4-positive hepatic progenitor cells and interlobular bile ducts were significantly correlated with the stage of liver disease (P<0.001), the grade of inflammation (P<0.001), and the activity of portal/septal myofibroblasts (P<0.001). rt-PCR study confirmed an increased TLR4 expression in the 26 patients analyzed with respect to controls (P<0.001). TLR4 expression positively correlated with fibrosis (P<0.05) and inflammation (P<0.05). The present results suggest that TLR4 expression by hepatic progenitor cells and biliary epithelial cells contributes to the progression of liver damage in the course of chronic HCV-related infection.
Autores: Latasa, María Ujué; Salis, F.; Garcia-Irigoyen, O.; et al.
Revista: PLOS ONE
ISSN 1932-6203  Vol. 7  Nº 12  2012  págs. e52711
Hepatocellular carcinoma (HCC) is the most prevalent liver tumor and a deadly disease with limited therapeutic options. Dysregulation of cell signaling pathways is a common denominator in tumorigenesis, including hepatocarcinogenesis. The epidermal growth factor receptor (EGFR) signaling system is commonly activated in HCC, and is currently being evaluated as a therapeutic target in combination therapies. We and others have identified a central role for the EGFR ligand amphiregulin (AR) in the proliferation, survival and drug resistance of HCC cells. AR expression is frequently up-regulated in HCC tissues and cells through mechanisms not completely known. Here we identify the ß-catenin signaling pathway as a novel mechanism leading to transcriptional activation of the AR gene in human HCC cells. Activation of ß-catenin signaling, or expression of the T41A ß-catenin active mutant, led to the induction of AR expression involving three specific ß-catenin-Tcf responsive elements in its proximal promoter. We demonstrate that HCC cells expressing the T41A ß-catenin active mutant show enhanced proliferation that is dependent in part on AR expression and EGFR signaling. We also demonstrate here a novel cross-talk of the EGFR system with fibroblast growth factor 19 (FGF19). FGF19 is a recently identified driver gene in hepatocarcinogenesis and an activator of ß-catenin signaling in HCC and colon cancer cells. We show that FGF19 induced AR gene expression through the ß-catenin pathway in human HCC cells. Importantly, AR up-regulation and EGFR signaling participated in the induction of cyclin D1 and cell proliferation elicited by FGF19. Finally, we demonstrate a positive correlation between FGF19 and AR expression in human HCC tissues, therefore supporting in clinical samples our experimental observations. These findings identify the AR/EGFR system as a key mediator of FGF19 responses in HCC cells involving ß-catenin signaling, and suggest that combined targeting of FGF19 and AR/EGFR may enhance therapeutic efficacy.
Autores: Monte, MJ; Latasa, María Ujué; et al.
ISSN 0168-8278  Vol. 56  Nº 2  2012  págs. 367 - 373
Background & Aims Bile acids (BA) are increasingly recognized as important modulators of liver regeneration. Increased enterohepatic BA flux has been proposed to generate specific signals that activate hepatocyte proliferation after partial hepatectomy (PH). We have investigated the role of the BA membrane transporter Mrp3 (Abcc3), which is expressed in the liver and gut, in the hepatic growth response elicited by BA and in liver regeneration after PH. Methods Liver growth and regeneration, and the expression of growth-related genes, were studied in Mrp3+/+ and Mrp3¿/¿ mice fed a cholic acid (CA) supplemented diet and after 2/3 PH. Activation of the BA receptor FXR was measured in mice after in vivo transduction of the liver with a FXR-Luciferase reporter plasmid. BA levels were measured in portal serum and liver tissue by high performance liquid chromatography-tandem mass spectrometry. Results Liver growth elicited by CA feeding was significantly reduced in Mrp3¿/¿ mice. These animals showed reduced FXR activation in the liver after CA administration and decreased portal serum levels of BA. Liver regeneration after PH was significantly delayed in Mrp3-deficient mice. Proliferation-related gene expression and peak DNA synthesis in Mrp3¿/¿ mice occurred later than in wild types, coinciding with a retarded elevation in intra-hepatic BA levels. Conclusions Lack of Abcc3 expression markedly impairs liver growth in response to BA and after PH. Our data suggest that Mrp3 plays a non-redundant role in the regulation of BA flux during liver regeneration.
Autores: Uriarte, Iker; Fernández de Barrena, Sara Elena; Monte, M. J.; et al.
ISSN 0270-9139  Vol. 56  Nº Supl. 1  2012  págs. 239A
Autores: Uriarte, Iker; De Barrena, M. G. F; Monte, M. J; et al.
ISSN 0168-8278  Vol. 56  2012  págs. S29-S29
Autores: Ávila, Matías Antonio;
ISSN 0168-8278  Vol. 54  Nº 3  2011  págs. 403 - 405
Autores: Berasain, C; Latasa, María Ujué; Goñi, S; et al.
Revista: CANCERS
ISSN 2072-6694  Vol. 3  Nº 2  2011  págs. 2444 - 2461
Hepatocarcinogenesis is a complex multistep process in which many different molecular pathways have been implicated. Hepatocellular carcinoma (HCC) is refractory to conventional chemotherapeutic agents, and the new targeted therapies are meeting with limited success. Interreceptor crosstalk and the positive feedback between different signaling systems are emerging as mechanisms of targeted therapy resistance. The identification of such interactions is therefore of particular relevance to improve therapeutic efficacy. Among the different signaling pathways activated in hepatocarcinogenesis the epidermal growth factor receptor (EGFR) system plays a prominent role, being recognized as a ¿signaling hub¿ where different extracellular growth and survival signals converge. EGFR can be transactivated in response to multiple heterologous ligands through the physical interaction with multiple receptors, the activity of intracellular kinases or the shedding of EGFR-ligands. In this article we review the crosstalk between the EGFR and other signaling pathways that could be relevant to liver cancer development and treatment.
Autores: Latasa, María Ujué; Demartis, MI; Balzani, S; et al.
Revista: Hepatology
ISSN 0270-9139  Vol. 54  Nº 6  2011  págs. 2149 - 2158
The identification of molecular mechanisms involved in the maintenance of the transformed phenotype of hepatocellular carcinoma (HCC) cells is essential for the elucidation of therapeutic strategies. Here, we show that human HCC cells display an autocrine
Autores: Andreu-Pérez, P; Esteve-Puig, R; de Torre-Minguela, C; et al.
ISSN 1937-9145  Vol. 4  Nº 190  2011  págs. ra58
The RAS to extracellular signal-regulated kinase (ERK) signal transduction cascade is crucial to cell proliferation, differentiation, and survival. Although numerous growth factors activate the RAS-ERK pathway, they can have different effects on the amplitude and duration of the ERK signal and, therefore, on the biological consequences. For instance, nerve growth factor, which elicits a larger and more sustained increase in ERK phosphorylation in PC12 cells than does epidermal growth factor (EGF), stimulates PC12 cell differentiation, whereas EGF stimulates PC12 cell proliferation. Here, we show that protein arginine methylation limits the ERK1/2 signal elicited by particular growth factors in different cell types from various species. We found that this restriction in ERK1/2 phosphorylation depended on methylation of RAF proteins by protein arginine methyltransferase 5 (PRMT5). PRMT5-dependent methylation enhanced the degradation of activated CRAF and BRAF, thereby reducing their catalytic activity. Inhibition of PRMT5 activity or expression of RAF mutants that could not be methylated not only affected the amplitude and duration of ERK phosphorylation in response to growth factors but also redirected the response of PC12 cells to EGF from proliferation to differentiation. This additional level of regulation within the RAS pathway may lead to the identification of new targets for therapeutic intervention.
Autores: Latasa, María Ujué; Demartis, M. I. ; Balzani, S.; et al.
ISSN 0270-9139  Vol. 54  Nº 6  2011  págs. 2149 - 2158
The identification of molecular mechanisms involved in the maintenance of the transformed phenotype of hepatocellular carcinoma (HCC) cells is essential for the elucidation of therapeutic strategies. Here, we show that human HCC cells display an autocrine loop mediated by connective tissue growth factor (CTGF) that promotes DNA synthesis and cell survival. Expression of CTGF was stimulated by epidermal growth factor receptor (EGFR) ligands and was dependent on the expression of the transcriptional coactivator, Yes-associated protein (YAP). We identified elements in the CTGF gene proximal promoter that bound YAP-enclosing complexes and were responsible for basal and EGFR-stimulated CTGF expression. We also demonstrate that YAP expression can be up-regulated through EGFR activation not only in HCC cells, but also in primary human hepatocytes. CTGF contributed to HCC cell dedifferentiation, expression of inflammation-related genes involved in carcinogenesis, resistance toward doxorubicin, and in vivo HCC cell growth. Importantly, CTGF down-regulated tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2 expression and was involved in the reduced sensitivity of these cells toward TRAIL-mediated apoptosis. CONCLUSION: We have identified autocrine CTGF as a novel determinant of HCC cells' neoplastic behavior. Expression of CTGF can be stimulated through the EGFR-signaling system in HCC cells in a novel cross-talk with the oncoprotein YAP. Moreover, to our knowledge, this is the first study that identifies a signaling mechanism triggering YAP gene expression in healthy and transformed liver parenchymal cells.
Autores: Berasain, C; Goñi, S; Latasa, María Ujué; et al.
ISSN 1007-9327  Vol. 16  Nº 25  2010  págs. 3091 - 3102
Pre-mRNA splicing is an essential step in the process of gene expression in eukaryotes and consists of the removal of introns and the linking of exons to generate mature mRNAs. This is a highly regulated mechanism that allows the alternative usage of exons, the retention of intronic sequences and the generation of exonic sequences of variable length. Most human genes undergo splicing events, and disruptions of this process have been associated with a variety of diseases, including cancer. Hepatocellular carcinoma (HCC) is a molecularly heterogeneous type of tumor that usually develops in a cirrhotic liver. Alterations in pre-mRNA splicing of some genes have been observed in liver cancer, and although still scarce, the available data suggest that splicing defects may have a role in hepatocarcinogenesis. Here we briefly review the general mechanisms that regulate pre-mRNA splicing, and discuss some examples that illustrate how this process is impaired in liver tumorigenesis, and may contribute to HCC development. We believe that a more thorough examination of pre-mRNA splicing is still needed to accurately draw the molecular portrait of liver cancer. This will surely contribute to a better understanding of the disease and to the development of new effective therapies. (C) 2010 Baishideng. All rights reserved.
Autores: Andreu-Pérez, P; Hernández-Losa, J; Moline, T; et al.
ISSN 1471-2407  Vol. 8  Nº 10  2010  págs. 265 - 276
Autores: Latasa, María Ujué; Gil, Maria del Carmen; et al.
Revista: PLoS One
ISSN 1932-6203  Vol. 5  Nº 12  2010  págs. e15690
Background: Inflammation and fibrogenesis are directly related to chronic liver disease progression, including hepatocellular carcinoma (HCC) development. Currently there are few therapeutic options available to inhibit liver fibrosis. We have evaluated the hepatoprotective and anti-fibrotic potential of orally-administered 59-methylthioadenosine (MTA) in Mdr2(-/-) mice, a clinically relevant model of sclerosing cholangitis and spontaneous biliary fibrosis, followed at later stages by HCC development. Methodology: MTA was administered daily by gavage to wild type and Mdr2(-/-) mice for three weeks. MTA anti-inflammatory and anti-fibrotic effects and potential mechanisms of action were examined in the liver of Mdr2(-/-) mice with ongoing fibrogenesis and in cultured liver fibrogenic cells (myofibroblasts). Principal Findings: MTA treatment reduced hepatomegaly and liver injury. alpha-Smooth muscle actin immunoreactivity and collagen deposition were also significantly decreased. Inflammatory infiltrate, the expression of the cytokines IL6 and Mcp-1, pro-fibrogenic factors like TGF beta 2 and tenascin-C, as well as pro-fibrogenic intracellular signalling pathways were reduced by MTA in vivo. MTA inhibited the activation and proliferation of isolated myofibroblasts and down-regulated cyclin D1 gene expression at the transcriptional level. The expression of JunD, a key transcription factor in liver fibrogenesis, was also reduced by MTA in activated myofibroblasts. Conclusions/Significance: Oral MTA administration was well tolerated and proved its efficacy in reducing liver inflammation and fibrosis. MTA may have multiple molecular and cellular targets. These include the inhibition of inflammatory and profibrogenic cytokines, as well as the attenuation of myofibroblast activation and proliferation. Downregulation of JunD and cyclin D1 expression in myofibroblasts may be important regarding the mechanism of action of MTA. This compound could be a good candidate to be tested for the treatment of (biliary) liver fibrosis.
Autores: Berasain, C; Ávila, Matías Antonio;
Libro:  Studies on hepatic disorders
2015  págs. 449 - 477
Hepatocellular carcinoma (HCC) is a complex and heterogeneous tumor with multiple molecular and genetic alterations. The major etiological factors for HCC are hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, alcoholic liver disease (ALD), and non-alcoholic steatohepatitis (NASH). A large body of observations demonstrates that HBV, HCV, ALD, and NASH induce hepatic oxidative stress, with increased oxidative DNA damage, lipid peroxidation, and decreased activity of cellular antioxidant systems. These evidences are found both in patients and in rodent models. Here we review the mechanisms by which HCV and HBV infection, as well as NASH, promote oxidative stress. We also describe the experimental evidence supporting a mechanistic role for oxidative stress in HCC development, and the rationale for the use of antioxidants in HCC chemoprevention.
Autores: Quiroga, Jorge Augusto; Sangro, Bruno; et al.
Libro:  Tratado de Medicina Farmacéutica
2010  págs. 261 - 277