Nuestros investigadores

Iria Vázquez Urio

Publicaciones científicas más recientes (desde 2010)

Autores: Ariceta, B.; Manu, A.; Larráyoz, María José; et al.
ISSN 0390-6078  Vol. 104  Nº S3  2019  págs. 249 - 249
Autores: Vázquez, Iria; Ariceta, B.; et al.
ISSN 0390-6078  Vol. 104  Nº S3  2019  págs. 110 - 110
Autores: Vázquez, Iria; Ails, R.; et al.
ISSN 1874-9399  Vol. 1860  Nº 6  2017  págs. 721 - 729
Transcriptional activation of the EVI1 oncogene (3q26) leads to aggressive forms of human acute myeloid leukemia (AML). However, the mechanism of EVI1-mediated leukemogenesis has not been fully elucidated. Previously, by characterizing the EVI1 promoter, we have shown that RUNX1 and ELK1 directly regulate EVI1 transcription. Intriguingly, bioinformatic analysis of the EVI1 promoter region identified the presence of several EVI1 potential binding sites. Thus, we hypothesized that EVI1 could bind to these sites regulating its own transcription. In this study, we show that there is a functional interaction between EVI1 and its promoter, and that the different EVI1 isoforms (EVI1-145 kDa, EVI1-Delta 324 and MDS1-EVI1) regulate the transcription of EVI1 transcripts through distinct promoter regions. Moreover, we determine that the EVI1-145 kDa isoform activates EVI1 transcription, whereas EVI1-Delta 324 and MDS1-EVI1 act as repressors. Finally, we demonstrate that these EVI1 isoforms are involved in cell transformation; functional experiments show that EVI1-145 kDa prolongs the maintenance of hematopoietic stem and progenitor cells; conversely, MDS1-EVI1 repressed hematopoietic stem and progenitor colony replating capacity. We demonstrate for the first time that EVI1 acts as a regulator of its own expression, highlighting the complex regulation of EVI1, and open new directions to better understand the mechanisms of EVI1 overexpressing leukemias.
Autores: Garcia-Ramirez, P.; Vicente, Carmen; Arriazu, Elena; et al.
ISSN 0390-6078  Vol. 102  2017  págs. 50 - 50
Autores: Fernández, Marta; Larráyoz, María José; Vázquez, Iria; et al.
ISSN 0390-6078  Vol. 102  Nº Supl. 2  2017  págs. 46 - 46
Autores: Alignani, D.; Delgado, JA; et al.
ISSN 1749-4478  Vol. 41  Nº 5  2016  págs. 606-611
Autores: Chen, L. ; Lai, Y. ; Zhu, X. ; et al.
ISSN 0021-9533  Vol. 128  Nº 2  2015  págs. 421
Autores: Asbagh, L. A. ; Vázquez, Iria; Vecchione, L. ; et al.
ISSN 1949-2553  Vol. 5  Nº 20  2014  págs. 10070 - 10083
Inappropriate activation of epidermal growth factor receptor (EGFR) plays a causal role in many cancers including colon cancer. The activation of EGFR by phosphorylation is balanced by receptor kinase and protein tyrosine phosphatase activities. However, the mechanisms of negative EGFR regulation by tyrosine phosphatases remain largely unexplored. Our previous results indicate that protein tyrosine phosphatase receptor type O (PTPRO) is down-regulated in a subset of colorectal cancer (CRC) patients with a poor prognosis. Here we identified PTPRO as a phosphatase that negatively regulates SRC by directly dephosphorylating Y416 phosphorylation site. SRC activation triggered by PTPRO down-regulation induces phosphorylation of both EGFR at Y845 and the c-CBL ubiquitin ligase at Y731. Increased EGFR phosphorylation at Y845 promotes its receptor activity, whereas enhanced phosphorylation of c-CBL triggers its degradation promoting EGFR stability. Importantly, hyperactivation of SRC/EGFR signaling triggered by loss of PTPRO leads to high resistance of colon cancer to EGFR inhibitors. Our results not only highlight the PTPRO contribution in negative regulation of SRC/EGFR signaling but also suggest that tumors with low PTPRO expression may be therapeutically targetable by anti-SRC therapies.
Autores: Dok, R. ; Kalev, P. ; Van Limbergen, E. J. ; et al.
ISSN 0008-5472  Vol. 74  Nº 6  2014  págs. 1739 - 1751
The p16INK4a protein is a principal cyclin-dependent kinase inhibitor that decelerates the cell cycle. Abnormally high levels of p16INK4a are commonly observed in human papillomavirus (HPV)-positive head and neck squamous cell carcinomas (HNSCC). We and others found that p16INK4a overexpression is associated with improved therapy response and survival of patients with HNSCC treated with radiotherapy. However, the functional role of p16INK4a in HNSCC remains unexplored. Our results implicate p16INK4a in regulation of homologous recombination-mediated DNA damage response independently from its role in control of the cell cycle. We found that expression of p16INK4a dramatically affects radiation sensitivity of HNSCC cells. p16INK4a overexpression impairs the recruitment of RAD51 to the site of DNA damage in HPV-positive cells by downregulating of cyclin D1 protein expression. Consistent with the in vitro findings, immunostaining of HNSCC patient samples revealed that high levels p16INK4a expression significantly correlated with decreased cyclin D1 expression. In summary, these findings reveal an unexpected function of p16INK4a in homologous recombination-mediated DNA repair response and imply p16INK4a status as an independent marker to predict response of patients with HNSCC to radiotherapy.
Autores: Kalev, P. ; Simicek, M. ; Vázquez, Iria; et al.
ISSN 0008-5472  Vol. 72  Nº 24  2012  págs. 6414 - 6424
Reversible phosphorylation plays a critical role in DNA repair. Here, we report the results of a loss-of-function screen that identifies the PP2A heterotrimeric serine/threonine phosphatases PPP2R2A, PPP2R2D, PPP2R5A, and PPP2R3C in double-strand break (DSB) repair. In particular, we found that PPP2R2A-containing complexes directly dephosphorylated ATM at S367, S1893, and S1981 to regulate its retention at DSB sites. Increased ATM phosphorylation triggered by PPP2R2A attenuation dramatically upregulated the activity of the downstream effector kinase CHK2, resulting in G(1) to S-phase cell-cycle arrest and downregulation of BRCA1 and RAD51. In tumor cells, blocking PPP2R2A thereby impaired the high-fidelity homologous recombination repair pathway and sensitized cells to small-molecule inhibitors of PARP. We found that PPP2R2A was commonly downregulated in non-small cell lung carcinomas, suggesting that PPP2R2A status may serve as a marker to predict therapeutic efficacy to PARP inhibition. In summary, our results deepen understanding of the role of PP2A family phosphatases in DNA repair and suggest PPP2R2A as a marker for PARP inhibitor responses in clinic.
Autores: Maicas, M.; Vázquez, Iria; Vicente, Eva; et al.
ISSN 0950-9232  Vol. 32  Nº 16  2012  págs.  2069 - 2078
The EVI1 gene (3q26) codes for a transcription factor with important roles in normal hematopoiesis and leukemogenesis. High expression of EVI1 is a negative prognostic indicator of survival in acute myeloid leukemia (AML) irrespective of the presence of 3q26 rearrangements. However, the only known mechanisms that lead to EVI1 overexpression are 3q aberrations, and the MLL-ENL oncoprotein, which activates the transcription of EVI1 in hematopoietic stem cells. Our aim was to characterize the functional promoter region of EVI1, and to identify transcription factors involved in the regulation of this gene. Generation of seven truncated constructs and luciferase reporter assays allowed us to determine a 318-bp region as the minimal promoter region of EVI1. Site-directed mutagenesis and chromatin immunoprecipitation (ChIP) assays identified RUNX1 and ELK1 as putative transcription factors of EVI1. Furthermore, knockdown of RUNX1 and ELK1 led to EVI1 downregulation, and their overexpression to upregulation of EVI1. Interestingly, in a series of patient samples with AML at diagnosis, we found a significant positive correlation between EVI1 and RUNX1 at protein level. Moreover, we identified one of the roles of RUNX1 in the activation of EVI1 during megakaryocytic differentiation. EVI1 knockdown significantly inhibited the expression of megakaryocytic markers after treating K562 cells with TPA, as happens when knocking down RUNX1. In conclusion, we define the minimal promoter region of EVI1 and demonstrate that RUNX1 and ELK1, two proteins with essential functions in hematopoiesis, regulate EVI1 in AML. Furthermore, our results show that one of the mechanisms by which RUNX1 regulates the transcription of EVI1 is by acetylation of the histone H3 on its promoter region. This study opens new directions to further understand the mechanisms of EVI1 overexpressing leukemias.
Autores: Vázquez, Iria; Cervera, J.; et al.
ISSN 0390-6078  Vol. 96  Nº 10  2011  págs. 1448 - 1456
Our results identify EVI1 over-expression as a poor prognostic marker in a large, independent cohort of acute myeloid leukemia patients less than 65 years old, and show that the total absence of EVI1 expression has a prognostic impact on the outcome of such patients. Furthermore, we demonstrated for the first time that an aberrant epigenetic pattern involving DNA methylation, H3 and H4 acetylation, and trimethylation of histone H3 lysine 4 and histone H3 lysine 27 might play a role in the transcriptional regulation of EVI1 in acute myeloid leukemia. This study opens new avenues for a better understanding of the regulation of EVI1 expression at a transcriptional level.
Autores: Vicente, C.; Vázquez, Iria; Conchillo, Ana; et al.
ISSN 0887-6924  Vol. 26  Nº 3  2011  págs. 550 - 554
Autores: Conchillo, Ana; Vázquez, 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.
Autores: Vázquez, Iria; Marcotegui, Nerea; et al.
ISSN 0027-8424  Vol. 107  Nº 44  2010  págs. E167 - E168