MicroRNA-10b inhibition reduces E2F1-mediated transcription and miR-15/16 activity in glioblastoma.
MicroRNA-10b (miR-10b) is commonly elevated in glioblastoma (GBM), while not expressed in normal brain tissues. Targeted inhibition of miR-10b has pleiotropic effects on GBM derived cell lines, it reduces GBM growth in animal models, but does not affect normal neurons and astrocytes. This data raises the possibility of developing miR-10b-targeting GBM therapy. However, the mechanisms contributing to miR-10b-mediated glioma cell survival and proliferation are unexplored. We found that inhibition of miR-10b has distinct effects on specific glioma cell lines. In cells expressing high levels of tumor suppressor p21WAF1/Cip1, it represses E2F1-mediated transcription, leading to down-regulation of multiple E2F1 target genes encoding for S-phase specific proteins, epigenetic modulators, and miRNAs (e.g. miR-15/16), and thereby stalling progression through the S-phase of cell cycle. Subsequently, miR-15/16 activities are reduced and many of their direct targets are de-repressed, including ubiquitin ligase FBXW7 that destabilizes Cyclin E. Conversely, GBM cells expressing low p21 level, or after p21 knock-down, exhibit weaker or no E2F1 response to miR-10b inhibition. Comparative analysis of The Cancer Genome Atlas revealed a strong correlation between miR-10b and multiple E2F target genes in GBM and low-grade glioma. Taken together, these findings indicate that miR-10b regulates E2F1-mediated transcription in GBM, in a p21-dependent fashion.
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Nadiya M
NM
Teplyuk
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Erik J
EJ
Uhlmann
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Andus Hon-Kit
AH
Wong
Regulus Therapeutics, Inc., San Diego, CA, USA.
Priya
P
Karmali
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Meenakshi
M
Basu
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Galina
G
Gabriely
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Anant
A
Jain
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Yang
Y
Wang
Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
E Antonio
EA
Chiocca
Cancer Research and Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD, USA.
Robert
R
Stephens
Regulus Therapeutics, Inc., San Diego, CA, USA.
Eric
E
Marcusson
Cancer Research and Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD, USA.
Ming
M
Yi
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Anna M
AM
Krichevsky
D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D048708:Cell Growth Processes / Q000235:genetics; D045744:Cell Line, Tumor; D050687:E2F1 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; C547183:MIRN10 microRNA, human; C505361:MIRN15 microRNA, human; C505362:MIRN16 microRNA, human; D035683:MicroRNAs