BACKGROUND Androgens play a critical role in the growth of both androgen dependent and castration-resistant prostate cancer (CRPC). Only a few micro-RNAs (miRNAs) have been suggested to be androgen regulated. We aim to identify androgen regulated miRNAs.   
 METHODS We utilized LNCaP derived model, we have established, and which overexpresses the androgen receptor (AR), the VCaP cell line, and 13 intact-castrated prostate cancer (PC) xenograft pairs, as well as clinical specimens of untreated (PC) and CRPC. The expression of miRNAs was analyzed by microarrays and quantitative RT-PCR (Q-RT-PCR). Transfection of pre-miR-141 and anti-miR-141 was also used.   
 RESULTS Seventeen miRNAs were > 1.5-fold up- or downregulated upon dihydrotestosterone (DHT) treatment in the cell lines, and 42 after castration in the AR-positive xenografts. Only four miRNAs (miR-10a, miR-141, miR-150*, and miR-1225-5p) showed similar androgen regulation in both cell lines and xenografts. Of those, miR-141 was found to be expressed more in PC and CRPC compared to benign prostate hyperplasia. Additionally, the overexpression of miR-141 enhanced growth of parental LNCaP cells while inhibition of miR-141 by anti-miR-141 suppressed the growth of the LNCaP subline overexpressing AR.   
 CONCLUSIONS Only a few miRNAs were found to be androgen-regulated in both cell lines and xenografts models. Of those, the expression of miR-141 was upregulated in cancer. The ectopic overexpression of miR-141 increased growth of LNCaP cell suggesting it may contribute to the progression of PC.
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