MicroRNA 100: a context dependent miRNA in prostate cancer

OBJECTIVE MicroRNAs are noncoding RNA molecules involved in the development and progression of tumors. We have found that miRNA-100 is underexpressed in metastatic prostate cancer compared to localized disease. Conversely higher levels of miR-100 are related to biochemical recurrence after surgery. This suggests that miR-100 may be a context-dependent miRNA, acting as oncogene or tumor suppressor miRNA. Our aim is to demonstrate the role of miR-100 in the control of predicted target genes in prostate cancer cell lines. METHODS Cell lines DU145 and PC3 were transfected with miR-100, antimiR-100 and after 24 h and 48 h of exposure, qRT-PCR and western blot were performed for mTOR, FGFR3, THAP2, SMARCA5 and BAZ2A. RESULTS There was reduction in mTOR (p=0.025), THAP2 (p=0.038), SMARCA5 (p=0.001) and BAZ2A (p=0.006) mRNA expression in DU145 cells after exposure to miR-100. In PC3 cells, mTOR expression was decreased by miR-100 (p=0.01). There was a reduction in the expression levels of proteins encoded by studied genes, ranging from 34% to 69%. CONCLUSIONS We demonstrate that miR-100 is a context-dependent miRNA controlling BAZ2, mTOR, FGFR3, SMARCA5 and THAP2 that might be involved in PC progression. The elucidation of the roles of miRNAs in tumors is important because they can be used as therapeutic targets in the future.