Research Express@NCKU - Articles Digest
Research Express@NCKU Volume 22 Issue 8 - July 20, 2012 [ http://research.ncku.edu.tw/re/articles/e/20120720/4.html ]
MicroRNA-330 acts as tumor suppressor and induces
apoptosis of prostate cancer cells through E2F1-
mediated suppression of Akt phosphorylation
K-H Lee
1, Y-L Chen
2, S-D Yeh
3, M Hsiao
4, J-T Lin
5, Y-G Goan
6,7and P-J Lu
*81Institute of Basic Medical Sciences, 2Institute of Oral Medicine and 8Institute of Clinical Medicine, National Cheng Kung University, College of Medicine, Tainan, Taiwan; 3Department of Urology, Taipei Medical University, Taipei, Taiwan; 4Genomics Research Center, Academia Sinica, Taipei, Taiwan; 5Division of Urology Surgery and 6Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; and 7Department of Surgery, National Yang-Ming University, Taipei, Taiwan
pjlu2190@mail.ncku.edu.tw Oncogene 2009;28:3360-3370
M
icroRNAs (miRNAs) are short (about 22 nucleotides in length) single-stranded regulatory RNAs that interact with multiple mRNAs resulting in either translational repression or degradation. A number of studies have demonstrated that deregulation of miRNAs associates with cancer development and tumorigenesis. So far, the number of human miRNAs has been reported in excess of 700 and about one hundred miRNAs have been demonstrated to associate with various cancer development including breast cancer, leukemia, lung cancer, colon cancer, brain cancer and liver cancer. The roles of most miRNAs in tumorigenesis however remained to be clarified. This study attempted toinvestigate the roles of prostate cancer related miRNAs in prostate tumorigenesis. We demonstrated that miR-330 was significantly down-regulated in human prostate cancer cell lines compared with nontumorigenic prostate epithelial cells. The results of bioinformatics analyses and luciferase reporter assay revealed that miR-330 can negatively regulate E2F1 protein expression (Fig. 1). The expression level of miR-330 and E2F1 was inversely correlated in both prostate cancer cell lines and cancer tissue specimens. Together with the over-expression of miR- 330 in PC-3 cells can suppress the E2F1-mediated Akt phosphorylation signaling and cause apoptosis, these evidences suggest the important roles of miR-330 in prostate cancer cells and the down-regulation of miR-330 may be involved in prostate tumorigenesis by targeting on E2F1-AKT signaling (Fig.2 and 3). Our study highlights the role of miR-330 in prostate cancer cells that may serve as a new therapeutic target for cancer treatment in the future.
Figure 1. Inverse correlation of miR-330 and E2F1 expression level in clinical prostate tissues. Relative miR- 330 (a) and E2F1 protein (b) expression levels in prostate non-tumor and tumor specimens.
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Research Express@NCKU - Articles Digest
Figure 2. MiR-330 regulates E2F1 at post transcriptional level and suppresses cell proliferation. (a and b) Relative miR-330 expression and western blot analysis of E2F1 and cyclinD1 in PC-3 after pre-miR-330 or anti- miR-330 transfection as indicated. (c) Focus-forming assay of pre-miR-330 transfected PC-3. (d) E2F1
overexpression restored miR-330-induced decrease of Akt, Bad, caspase-9 phosphorylation and PARP cleavage.
Figure 3. Induction of apoptosis in PC-3 cells by pre-miR-330 through suppression of Akt phosphorylation.
(a) Detection and comparison of control-miR (upper panel) or pre-miR-330 (lower panel) modulated intracellular kinases in PC-3 cells by human phosphorylated mitogen-activated protein kinase (MAPK) array. (b) Western blot analysis of Akt phosphorylation and apoptosis-associated proteins after pre-miR-330 or myr-Akt cotransfection.
(c) Model of cellular apoptosis triggered by tumor suppressor miR-330 through E2F1-mediated pathway.
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