Prostate cancer (PCa) is the most frequent male malignancy and the second most common cause of cancer-related death in Western countries. Current clinical and pathological methods are limited in the prediction of postoperative outcome. It is becoming increasingly evident that small non-coding RNA (ncRNA) species are associated with the development and progression of this malignancy. To assess the diversity and abundance of small ncRNAs in PCa, we analyzed the composition of the entire small transcriptome by Illumina/ Solexa deep sequencing. We further analyzed the micro-RNA (miRNA) expression signatures of 102 fresh-frozen patient samples during PCa progression by miRNA microarrays. Both platforms were cross-validated by quantitative reverse transcriptase-PCR. Besides the altered expression of several miRNAs, our deep sequencing analyses revealed strong differential expression of small nucleolar RNAs (snoRNAs) and transfer RNAs (tRNAs). From microarray analysis, we derived a miRNA diagnostic classifier that accurately distinguishes normal from cancer samples. Furthermore, we were able to construct a PCa prognostic predictor that independently forecasts postoperative outcome. Importantly, the majority of miRNAs included in the predictor also exhibit high sequence counts and concordant differential expression in Illumina PCa samples, supported by quantitative reverse transcriptase-PCR. Our findings provide miRNA expression signatures that may serve as an accurate tool for the diagnosis and prognosis of PCa.

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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. Prostate 71:604–614, 2011. © 2010 Wiley‐Liss, Inc.

AbstractmiRNAs have proven to be key regulators of gene expression and are differentially expressed in various diseases, including cancer. Our aim was to identify epigenetically dysregulated genes in prostate cancer. We performed miRNA expression profiling after relieving epigenetic modifications in 6 prostate cancer cell lines and nonmalignant prostate epithelial cells. Thirty‐eight miRNAs showed increased expression in any prostate cancer cell line after 5‐aza‐2′‐deoxycytidine (5azadC) and trichostatin A (TSA) treatments. Six of these also had decreased expression in clinical prostate cancer samples compared to benign prostatic hyperplasia. Among these, miR‐193b was methylated in 22Rv1 cell line at a CpG island ∼1 kb upstream of the miRNA locus. Expressing miR‐193b in 22Rv1 cells using pre‐miR‐193b oligonucleotides caused a significant growth reduction (p < 0.001) resulting from a decrease of cells in S‐phase of the cell cycle (p < 0.01). In addition, the anchorage independent growth was partially inhibited in transiently miR‐193b‐expressing 22Rv1 cells (p < 0.01). Altogether, our data suggest that miR‐193b is an epigenetically silenced putative tumor suppressor in prostate cancer.

Background: Diabetes has negative, and exercise training positive, effects on the skeletal muscle vasculature, but the mechanisms are not yet fully understood. In the present experiment the effects of running exercise on the mRNA expression of pro-and antiangiogenic factors were studied in healthy and diabetic skeletal muscle. The responses in capillaries and muscle fibers, collected from the muscle with laser capture microdissection, were also studied separately.