miR-34a functions as a tumor suppressor modulating EGFR in glioblastoma multiforme
Chromosome 1p36.23 is frequently deleted in glioblastoma multiforme (GBM). miR-34a localizes in this region. Our experiments found that miR-34a was often deleted and epidermal growth factor receptor (EGFR) was frequently amplified in genomic DNA of 55 GBMs using single-nucleotide polymorphism DNA mi...
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Published in | Oncogene Vol. 32; no. 9; pp. 1155 - 1163 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
28.02.2013
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | Chromosome 1p36.23 is frequently deleted in glioblastoma multiforme (GBM). miR-34a localizes in this region. Our experiments found that miR-34a was often deleted and epidermal growth factor receptor (EGFR) was frequently amplified in genomic DNA of 55 GBMs using single-nucleotide polymorphism DNA microarray. Notably, we found that the mean survival time was significantly shortened for patients whose GBMs had both EGFR amplification and miR-34a deletion. Expression of miR-34a was significantly lower in GBM samples compared with normal brain tissue. Forced expression of miR-34a in GBM cells decreased their ability to migrate and profoundly decreased their levels of cyclin-A1, -B1, -D1, and -D3, as well as cyclin-dependent kinase and increased expression of cyclin kinase inhibitor proteins (p21, p27). Also, human GBM cells (U251) stable overexpressing mir-34a formed smaller tumors when growing as xenografts in immunodeficient mice compared with wild-type U251 GBM cells. Furthermore, the protein expression of EGFR decreased in the cells with forced overexpression of miR-34a. Additional studies showed that mir-34a targeted Yin Yang-1 (YY1) and YY1 is a transcription factor that can stimulate the expression of EGFR. Thus, our data suggest that miR-34a acts as a tumor suppressor by inhibiting growth of GBM cells
in vitro
and
in vivo
associated with moderating the expression of cell-cycle proteins and EGFR. Moreover, we discovered for the first time that both deletion of miR-34a and amplification of EGFR were associated with significantly decreased overall survival of GBM patients. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 These authors contributed equally to this work and should be considered co-last authors. |
ISSN: | 0950-9232 1476-5594 |
DOI: | 10.1038/onc.2012.132 |