Yoon-Jae Cho

Publication Details

  • miR-34a confers chemosensitivity through modulation of MAGE-A and p53 in medulloblastoma NEURO-ONCOLOGY Weeraratne, S. D., Amani, V., Neiss, A., Teider, N., Scott, D. K., Pomeroy, S. L., Cho, Y. 2011; 13 (2): 165-175

    Abstract:

    Recent studies have established miR-34a as a key effector of the p53 signaling pathway and have implicated its role in multiple cancer types. Here, we establish that miR-34a induces apoptosis, G2 arrest, and senescence in medulloblastoma and renders these cells more sensitive to chemotherapeutic agents. These effects are mediated in part by the direct post-transcriptional repression of the oncogenic MAGE-A gene family. We demonstrate that miR-34a directly targets the 3' untranslated regions of MAGE-A genes and decreases MAGE-A protein levels. This decrease in MAGE-A results in a concomitant increase in p53 and its associated transcriptional targets, p21/WAF1/CIP1 and, importantly, miR-34a. This establishes a positive feedback mechanism where miR-34a is not only induced by p53 but increases p53 mRNA and protein levels through the modulation of MAGE-A genes. Additionally, the forced expression of miR-34a or the knockdown of MAGE-A genes by small interfering RNA similarly sensitizes medulloblastoma cells to several classes of chemotherapeutic agents, including mitomycin C and cisplatin. Finally, the analysis of mRNA and micro-RNA transcriptional profiles of a series of primary medulloblastomas identifies a subset of tumors with low miR-34a expression and correspondingly high MAGE-A expression, suggesting the coordinate regulation of these genes. Our work establishes a role for miR-34a in modulating responsiveness to chemotherapy in medulloblastoma and presents a novel positive feedback mechanism involving miR-34a and p53, via direct targeting of MAGE-A.

    View details for DOI 10.1093/neuonc/noq179

    View details for Web of Science ID 000287002700002

    View details for PubMedID 21177782

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