Identification of hsa-miR-135a target genes in the HeLa cell line

MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs. They act as negative regulators of protein-coding gene expression at the post-transcriptional level via sequence-specific interaction with the 3' UTR of targeted mRNAs. A miR-135a dysregulation has been observed in various cancers, where a dual role of oncomiR or of tumor suppressor has been reported for the cancers profiled to date; however, knowledge is limited to explain these contentious data. In the present study, we investigate the regulation and mechanism of action of miR-135a, including identification of functionally targets that contributes to its actions, in prostate cancer progression. We demonstrate that the expression of miR-135a is regulated by androgens, in a time- and dose-dependent manner and identify miR-135a as a direct target gene of the androgen receptor AR. A functional androgen response element (ARE) is identified in the promoter region of the miR-135a gene and ChIP assay reveal AR protein binding to. Anti-androgen treatment and AR-targeted siRNA knockdown strategy suggest a novel function for miR-135a in AR signaling. In silico prediction, transcriptomic and proteomic combined analyses lead to identify ROCK-1/-2 as two miR-135a-targeted genes. Luciferase reporter assays indicate that these two proteins are miR-135a's direct targets. We finally demonstrate that miR-135a acts through ROCK-1/-2 pathways to affect migration and invasion cellular processes. MiR-135a expression level was lower in surgical cancerous samples compared to paired adjacent non-tumoral tissues and was gradually diminished consistent with cancer progression, suggesting the significance of miR-135a-mediated prostate cancer transformation. Our findings define miR-135a as a candidate tumor suppressor and potential prognostic marker in human prostate cancer. Transcriptional profiling of the HeLa cell line that over-expressed hsa-miR-135a. HeLa cells were transfected with the hsa-miR-135a mimic (Ambion) and compared to control cells transfected with the negative control.