MicroRNAs (miRNAs) are noncoding small RNAs that repress protein translation by targeting specific messenger RNAs. miR-15a and miR-16-1 act as putative tumor suppressors by targeting the oncogene BCL2. These miRNAs form a cluster at the chromosomal region 13q14, which is frequently deleted in cancer. Here, we report that the miR-15a and miR-16-1 cluster targets CCND1 (encoding cyclin D1) and WNT3A, which promotes several tumorigenic features such as survival, proliferation and invasion. In cancer cells of advanced prostate tumors, the miR-15a and miR-16 level is significantly decreased, whereas the expression of BCL2, CCND1 and WNT3A is inversely upregulated. Delivery of antagomirs specific for miR-15a and miR-16 to normal mouse prostate results in marked hyperplasia, and knockdown of miR-15a and miR-16 promotes survival, proliferation and invasiveness of untransformed prostate cells, which become tumorigenic in immunodeficient NOD-SCID mice. Conversely, reconstitution of miR-15a and miR-16-1 expression results in growth arrest, apoptosis and marked regression of prostate tumor xenografts. Altogether, we propose that miR-15a and miR-16 act as tumor suppressor genes in prostate cancer through the control of cell survival, proliferation and invasion. These findings have therapeutic implications and may be exploited for future treatment of prostate cancer.

The interaction between cancer cells and microenvironment has a critical role in tumor development and progression. Although microRNAs regulate all the major biological mechanisms, their influence on tumor microenvironment is largely unexplored. Here, we investigate the role of microRNAs in the tumor-supportive capacity of stromal cells. We demonstrated that miR-15 and miR-16 are downregulated in fibroblasts surrounding the prostate tumors of the majority of 23 patients analyzed. Such downregulation of miR-15 and miR-16 in cancer-associated fibroblasts (CAFs) promoted tumor growth and progression through the reduced post-transcriptional repression of Fgf-2 and its receptor Fgfr1, which act on both stromal and tumor cells to enhance cancer cell survival, proliferation and migration. Moreover, reconstitution of miR-15 and miR-16 impaired considerably the tumor-supportive capability of stromal cells in vitro and in vivo. Our data suggest a molecular circuitry in which miR-15 and miR-16 and their correlated targets cooperate to promote tumor expansion and invasiveness through the concurrent activity on stromal and cancer cells, thus providing further support to the development of therapies aimed at reconstituting miR-15 and miR-16 in advanced prostate cancer.

Abstract. Current efforts to identify protein biomarkers of disease use mainly mass spectrometry (MS) to analyze tissue and blood specimens. The low-molecular-weight "peptidome" is an attractive information archive because of the facile nature by which the low-molecular-weight information freely crosses the endothelial cell barrier of the vasculature, which provides opportunity to measure disease microenvironmentassociated protein analytes secreted or shed into the extracellular interstitium and from there into the circulation. However, identifying useful protein biomarkers (peptidomic or not) which could be useful to detect early detection/monitoring of disease, toxicity, doping, or drug abuse has been severely hampered because even the most sophisticated, high-resolution MS technologies have lower sensitivities than those of the immunoassays technologies now routinely used in clinical practice. Identification of novel low abundance biomarkers that are indicative of early-stage events that likely exist in the sub-nanogram per milliliter concentration range of known markers, such as prostate-specific antigen, cannot be readily detected by current MS technologies. We have developed a new nanoparticle technology that can, in one step, capture, concentrate, and separate the peptidome from high-abundance blood proteins. Herein, we describe an initial pilot study whereby the peptidome content of ovarian and prostate cancer patients is investigated with this method. Differentially abundant candidate peptidome biomarkers that appear to be specific for early-stage ovarian and prostate cancer have been identified and reveal the potential utility for this new methodology

Our innovative technique is safe, effective and easy to perform. The oncological and functional results obtained with a long followup justify seminal sparing cystectomy as an excellent surgical procedure which can be proposed to some oncological and nononcological cases.

A favorable outcome of high intensity focused ultrasound is associated with lower baseline prostate specific antigen, lower prostate specific antigen nadir, lower Gleason score and lower tumor stage. As with any novel technology long-term data will be required before this technique gains widespread clinical acceptance.