miR-21 may acts as an oncomir by targeting RECK, a matrix metalloproteinase regulator, in prostate cancer

To determine if RECK is a target of miR-21 in prostate cancer we performed an in vitro assay with PCa cell line DU-145 transfected with pre-miR-21 and anti-miR-21. To determine miR-21 and RECK expression levels in PCa samples we performed quantitative real-time polymerase chain reaction (qRT-PCR).The in vitro assays showed a decrease in expression levels of RECK after transfection with pre-miR-21, and an increase of MMP9 that is regulated by RECK compared to PCa cells treated with anti-miR-21. We defined three profiles to compare the prognostic factors. The first was characterized by miR-21 and RECK underexpression (N？=？25) the second was characterized by miR-21 overexpression and RECK underexpression (N？=？12), and the third was characterized by miR-21 underexpression and RECK overexpression (N？=？16). From men who presented the second profile (miR-21 overexpression and RECK underexpression) 91.7% were staged pT3. For the other two groups 48.0%, and 46.7% of patients were staged pT3 (p？=？0.025).Our results demonstrate RECK as a target of miR-21. We believe that miR-21 may be important in PCa progression through its regulation of RECK, a known regulator of tumor cell invasion.Prostate cancer (PCa) is the most common cancer affecting males and the second leading cause of death in men in many countries, including Brazil. For 2011 903,500 new cases and 258,400 deaths are estimated worldwide [1]. Tumor staging, Gleason score and Prostatic specific antigen (PSA) serum levels are the most important prognostic factors; however, even taken together they cannot perfectly predict which patients are at risk for progression [2]. There is a variety of treatment options that ranges from active surveillance to androgen deprivation. Therefore, identification of molecular markers that could contribute to prediction of PCa behavior has been an area of active research.MicroRNAs (miRNAs) are a class of small noncoding RNA that regulate the expression of target genes by promoting translat