Nuestros investigadores

Marta María Alonso Roldán


Publicaciones científicas más recientes (desde 2010)

Autores: García-Romero, N., ; Carrión-Navarro, J., ; Esteban-Rubio, S. , ; et al.
ISSN 1949-2553  Vol. 8  Nº 1  2017  págs. 1416 - 1428
Tumor-cell-secreted extracellular vesicles (EVs) can cross the disrupted bloodbrain barrier (BBB) into the bloodstream. However, in certain gliomas, the BBB remains intact, which might limit EVs release. To evaluate the ability of tumor-derived EVs to cross the BBB, we used an orthotopic xenotransplant mouse model of human glioma-cancer stem cells featuring an intact BBB. We demonstrated that all types of tumor cells-derived EVs-apoptotic bodies, shedding microvesicles and exosomes-cross the intact BBB and can be detected in the peripheral blood, which provides a minimally invasive method for their detection compared to liquid biopsies obtained from cerebrospinal fluid (CSF). Furthermore, these EVs can be readily distinguished from total murine EVs, since they carry human-specific DNA sequences relevant for GBM biology. In a small cohort of glioma patients, we finally demonstrated that peripheral blood EVs cargo can be successfully used to detect the presence of IDH1(G395A), an essential biomarker in the current management of human glioma
Autores: Marigil Sánchez, Miguel; Martinez-Velez, N., ; Domínguez Echávarri, Pablo Daniel; et al.
Revista: PLOS ONE
ISSN 1932-6203  Vol. 12  Nº 1  2017  págs. e0170501
Objective In this work we set to develop and to validate a new in vivo frameless orthotopic Diffuse Intrinsic Pontine Glioma (DIPG) model based in the implantation of a guide-screw system. Methods It consisted of a guide-screw also called bolt, a Hamilton syringe with a 26-gauge needle and an insulin-like 15-gauge needle. The guide screw is 2.6 mm in length and harbors a 0.5 mm central hole which accepts the needle of the Hamilton syringe avoiding a theoretical displacement during insertion. The guide-screw is fixed on the mouse skull according to the coordinates: 1 mm right to and 0.8 mm posterior to lambda. To reach the pons the Hamilton syringe is adjusted to a 6.5 mm depth using a cuff that serves as a stopper. This system allows delivering not only cells but also any kind of intratumoral chemotherapy, antibodies or gene/viral therapies. Results The guide-screw was successfully implanted in 10 immunodeficient mice and the animals were inoculated with DIPG human cell lines during the same anesthetic period. All the mice developed severe neurologic symptoms and had a median overall survival of 95 days ranging the time of death from 81 to 116 days. Histopathological analysis confirmed tumor into the pons in all animals confirming the validity of this model. Conclusion Here we presented a reproducible and frameless DIPG model that allows for rapid evaluation of tumorigenicity and efficacy of chemotherapeutic or gene therapy products delivered intratumorally to the pons.
Autores: Inogés Sancho, Susana Inmaculada; Tejada Solís, Sonia; López Díaz de Cerio, Ascensión; et al.
ISSN 1479-5876  Vol. 15  Nº 1  2017  págs. 104-116
Our results suggest that the addition of tumor lysate-pulsed autologous DCs vaccination to tumor resection and combined radio-chemotherapy is feasible and safe. A multicenter randomized clinical trial is warranted to evaluate the potential survival benefit of this therapeutic approach. Trial registration This phase-II trial was registered as EudraCT: 2009-009879-35 and Identifier: NCT01006044 retrospectively registered.
Autores: Martínez-Vélez, N., ; Marigil Sánchez, Miguel; Aristu Mendioroz, José Javier; et al.
ISSN 1522-8517  Vol. 19  2017  págs. 28 - 28
Autores: García Moure, Marc; Martinez-Velez, N., ; Gonzalez-Huarriz, M., ; et al.
ISSN 1522-8517  Vol. 19  Nº Supl. 4  2017  págs. 42
Primitive Neuroectodermal Tumors (PNETs) are very rare aggressive pediatric tumors characterized by the presence of poorly differentiated tumor cells. Despite formidable advances in targeted therapies and in the knowledge of the molecular make-up of these tumors, the development of curative therapies is still lagging. Therefore, the outcome for children affected with PNETs still remains dismal. Thus, it is critical to propel alternative therapeutic approaches to improve the survival and quality of life of these children. Delta-24-RGD is an oncolytic adenovirus engineered to have a tumor restricted replication and an expanded tropism to cancer cells. Altogether, these modifications result in a potent antitumor and lack of toxicity as shown by preclinical and clinical studies. In this work we describe the antitumor effect mediated by Delta-24-RGD in PNETs (PFSK-1 and SK-PN-DW cells), as well as a in a new unpublished cell line (PBT-25) that we have generated from a tumor biopsy. First, we demonstrated in vitro that Delta-24-RGD transduces efficiently PNET cells leading to an effective replication yielding high titers of new infectious particles when compared with other type of brain tumors such as glioma. Treatment with the virus in vitro resulted in an effective cell killing effect, obtaining IC50 values ranging from 7 to 18 MOIs. In vivo, Delta-24-RGD showed a safety profile since no signs of toxicity were observed upon its administration. Finally, the antitumor effect of Delta-24-RGD was assessed in vivo in two orthotopic models of sPNET. Delta-24-RGD treatment resulted in a significant increase in overall survival of the animals (19 and 21 days for PFSK-1 and SK-PN-DW, respectively) compared to vehicle treated animals (14 days) and led to long-term survivors free of disease. In vivo antitumor effect in PBT-25 is on-going. In summary, these results demonstrate the potential therapeutic benefit of Delta-24-RGD for the treatment of PNETs.
Autores: Martínez-Vélez, N., ; Xipell Badals, Enric; Vera, B., ; et al.
ISSN 1078-0432  Vol. 22  Nº 9  2016  págs. 2217-25
These results uncover VCN-01 as a promising strategy for osteosarcoma, setting the bases to propel a phase I/II trial for kids with this disease.
Autores: Urtasun Alonso, Raquel; Elizalde Arbilla, María; Azkona Leiza, María Teresa; 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: Vera, B., ; Martínez-Vélez, N., ; Xipell Badals, Enric; et al.
Revista: PLOS ONE
ISSN 1932-6203  Vol. 11  Nº 1  2016  págs. e0147211
Despite the recent advances in the development of antitumor therapies, the prognosis for patients with malignant gliomas remains dismal. Therapy with tumor-selective viruses is emerging as a treatment option for this devastating disease. In this study we characterize the anti-glioma effect of VCN-01, an improved hyaluronidase-armed pRB-pathway-selective oncolytic adenovirus that has proven safe and effective in the treatment of several solid tumors. VCN-01 displayed a significant cytotoxic effect on glioma cells in vitro. In vivo, in two different orthotopic glioma models, a single intra-tumoral administration of VCN-01 increased overall survival significantly and led to long-term survivors free of disease.
Autores: Martinez Velez, N., ; Marigil Sánchez, Miguel; Domínguez Echávarri, Pablo Daniel; et al.
ISSN 1522-8517  Vol. 18  Nº Supl.6  2016  págs. 61
Autores: Tejada Solís, Sonia; Díez Valle, Ricardo; Gállego Pérez de Larraya, Jaime; et al.
ISSN 1522-8517  Vol. 18  Nº Supl.6  2016  págs. 4
Autores: Vera, B., ; Martínez-Vélez, N., ; Xipell, E., ; et al.
Revista: PLOS ONE
ISSN 1932-6203  Vol. 11  Nº 1  2015  págs. e0147211
Despite the recent advances in the development of antitumor therapies, the prognosis for patients with malignant gliomas remains dismal. Therapy with tumor-selective viruses is emerging as a treatment option for this devastating disease. In this study we characterize the anti-glioma effect of VCN-01, an improved hyaluronidase-armed pRB-pathway-selective oncolytic adenovirus that has proven safe and effective in the treatment of several solid tumors. VCN-01 displayed a significant cytotoxic effect on glioma cells in vitro. In vivo, in two different orthotopic glioma models, a single intra-tumoral administration of VCN-01 increased overall survival significantly and led to long-term survivors free of disease.
Autores: Martínez-Velez, N., ; Xipell, E., ; Jauregui Jiménez, Patricia; et al.
ISSN 0884-0431  Vol. 29  Nº 10  2014  págs. 2287 - 2296
Osteosarcoma is the most common malignant bone tumor in children and adolescents. The presence of metastases and the lack of response to conventional treatment are the major adverse prognostic factors. Therefore, there is an urgent need for new treatment strategies that overcome both of these problems. Our purpose was to elucidate whether the use of the oncolytic adenovirus ¿24-RGD alone or in combination with standard chemotherapy would be effective, in vitro and in vivo, against osteosarcoma. Our results showed that ¿24-RGD exerted a potent antitumor effect against osteosarcoma cell lines that was increased by the addition of cisplatin. ¿24-RGD osteosarcoma treatment resulted in autophagy in vitro that was further enhanced when combined with cisplatin. Of importance, administration of ¿24-RGD and/or cisplatin, in novel orthotopic and two lung metastatic models in vivo resulted in a significant reduction of tumor burden meanwhile maintaining a safe toxicity profile. Together, our data underscore the potential of ¿24-RGD to become a realistic therapeutic option for primary and metastatic pediatric osteosarcoma. Moreover, this study warrants a future clinical trial to evaluate the safety and efficacy of ¿24-RGD for this devastating disease.
Autores: Cristóbal Yoldi, Jon; García-Orti, L., ; Cirauqui, C., ; et al.
ISSN 0887-6924  Vol. 25  Nº 4  2011  págs. 606 - 614
Protein phosphatase 2A (PP2A) is a human tumor suppressor that inhibits cellular transformation by regulating the activity of several signaling proteins critical for malignant cell behavior. PP2A has been described as a potential therapeutic target in chronic myeloid leukemia, Philadelphia chromosome-positive acute lymphoblastic leukemia and B-cell chronic lymphocytic leukemia. Here, we show that PP2A inactivation is a recurrent event in acute myeloid leukemia (AML), and that restoration of PP2A phosphatase activity by treatment with forskolin in AML cells blocks proliferation, induces caspase-dependent apoptosis and affects AKT and ERK1/2 activity. Moreover, treatment with forskolin had an additive effect with Idarubicin and Ara-c, drugs used in standard induction therapy in AML patients. Analysis at protein level of the PP2A activation status in a series of patients with AML at diagnosis showed PP2A hyperphosphorylation in 78% of cases (29/37). In addition, we found that either deregulated expression of the endogenous PP2A inhibitors SET or CIP2A, overexpression of SETBP1, or downregulation of some PP2A subunits, might be contributing to PP2A inhibition in AML. In conclusion, our results show that PP2A inhibition is a common event in AML cells and that PP2A activators, such as forskolin or FTY720, could represent potential novel therapeutic targets in AML.
Autores: Alonso Roldán, Marta María; Díez Valle, Ricardo; Rubio, A; et al.
Revista: PLoS One
ISSN 1932-6203  Vol. 6  Nº 11  2011  págs.  -
We undertook this study to understand how the transcription factor Sox2 contributes to the malignant phenotype of glioblastoma multiforme (GBM), the most aggressive primary brain tumor. We initially looked for unbalanced genomic rearrangements in the Sox2
Autores: Bitarte Manzanal, Nerea; Bandres Elizalde, Eva María; Boni, V.; et al.
ISSN 1066-5099  Vol. 29  Nº 11  2011  págs. 1661 - 1671
Autores: Liu, D., ; Fueyo, J., ; Lee, OH., ; et al.
ISSN 1949-2553  Vol. 1  Nº 8  2010  págs. 700-709
Malignant gliomas are the prototype of highly infiltrative tumors and this characteristic is the main factor for the inevitable tumor recurrence and short survival after most aggressive therapies. The aberrant communication between glioma cells and tumor microenvironment represents one of the major factors regulating brain tumor dispersal. Our group has previously reported that the tyrosine kinase receptor Tie2/TEK is expressed in glioma cells and brain tumor stem cells and is associated with the malignant progression of these tumors. In this study, we sought to determine whether the angiopoietin 1 (Ang1)/Tie2 axis regulates crosstalk between glioma cells and endothelial cells. We found that Ang1 enhanced the adhesion of Tie2-expressing glioma and brain tumor stem cells to endothelial cells. Conversely, specific small interfering RNA (siRNA) knockdown of Tie2 expression inhibited the adhesion capability of glioma cells. Tie2 activation induced integrin ß1 and N-cadherin upregulation, and neutralizing antibodies against these molecules inhibited the adhesion of Tie2-positive glioma cells to endothelial cells. In 2D and 3D cultures, we observed that Ang1/Tie2 axis activation was related to increased glioma cell invasion, which was inhibited by using Tie2 siRNA. Importantly, intracranial co-implantation of Tie2-positive glioma cells and endothelial cells in a mouse model resulted in diffusely invasive tumors with cell clusters surrounding glomeruloid vessels mimicking a tumoral niche distribution. Collectively, our results provide new information about the Tie2 signaling in glioma cells that regulates the cross-talk between glioma cells and tumor microenvironment, envisioning Tie2 as a multi-compartmental target for glioma therapy.
Autores: Jiang, H., ; Martin, V., ; Alonso Roldán, Marta María; et al.
ISSN 1554-8627  Vol. 6  Nº 8  2010  págs. 1216-1217
Autores: Conchillo Armendáriz, Ana; García Garzón, María Antonia; Vázquez Urio, Iria; et al.
ISSN 0007-0920  Vol. 103  Nº 8  2010  págs. 1292 - 1296
BAKGROUND: The EVI1(ecotropic virus integration site 1) gene codes for a zinc-finger transcription factor, whose transcriptional activation leads to a particularly aggressive form of acute myeloid leukaemia (AML). Although, EVI1 interactions with key proteins in hematopoiesis have been previously described, the precise role of this transcription factor in promoting leukaemic transformation is not completely understood. Recent works have identified specific microRNA (miRNA) signatures in different AML subgroups. However, there is no analysis of miRNAs profiles associated with EVI1 overexpression in humans. METHODS: We performed QT-RT-PCR to assess the expression of 250 miRNAs in cell lines with or without EVI1 overexpression and in patient samples. We used ChIP assays to evaluated the possible binding of EVI1 binding to the putative miRNA promoter. Proliferation of the different cell lines transfected with the anti-or pre-miRs was quantified by MTT. RESULTS: Our data showed that EVI1 expression was significantly correlated with the expression of miR-1-2 and miR-133-a-1 in established cell lines and in patient samples. ChIP assays confirmed that EVI1 binds directly to the promoter of these two miRNAs. However, only miR-1-2 was involved in abnormal proliferation in EVI1 expressing cell lines. CONCLUSIONS: Our data showed that EVI1 controls proliferation in AML through modulation of miR-1-2. This study contributes to further understand the transcriptional networks involving transcription factors and miRNAs in AML.