In silico mining identifies IGFBP3 as a novel target of methylation in prostate cancer

Promoter hypermethylation is central in deregulating gene expression in cancer. Identification of novel methylation targets in specific cancers provides a basis for their use as biomarkers of disease occurrence and progression. We developed an in silico strategy to globally identify potential targets of promoter hypermethylation in prostate cancer by screening for 5′ CpG islands in 631 genes that were reported as downregulated in prostate cancer. A virtual archive of 338 potential targets of methylation was produced. One candidate, IGFBP3, was selected for investigation, along with glutathione-S-transferase pi (GSTP1), a well-known methylation target in prostate cancer. Methylation of IGFBP3 was detected by quantitative methylation-specific PCR in 49/79 primary prostate adenocarcinoma and 7/14 adjacent preinvasive high-grade prostatic intraepithelial neoplasia, but in only 5/37 benign prostatic hyperplasia (P<0.0001) and in 0/39 histologically normal adjacent prostate tissue, which implies that methylation of IGFBP3 may be involved in the early stages of prostate cancer development. Hypermethylation of IGFBP3 was only detected in samples that also demonstrated methylation of GSTP1 and was also correlated with Gleason score ⩾7 (P=0.01), indicating that it has potential as a prognostic marker. In addition, pharmacological demethylation induced strong expression of IGFBP3 in LNCaP prostate cancer cells. Our concept of a methylation candidate gene bank was successful in identifying a novel target of frequent hypermethylation in early-stage prostate cancer. Evaluation of further relevant genes could contribute towards a methylation signature of this disease

Targeting of distinct signaling cascades and cancer-associated fibroblasts define the efficacy of Sorafenib against prostate cancer cells

Sorafenib, a multi-tyrosine kinase inhibitor, kills more effectively the non-metastatic prostate cancer cell line 22Rv1 than the highly metastatic prostate cancer cell line PC3. In 22Rv1 cells, constitutively active STAT3 and ERK are targeted by sorafenib, contrasting with PC3 cells, in which these kinases are not active. Notably, overexpression of a constitutively active MEK construct in 22Rv1 cells stimulates the sustained phosphorylation of Bad and protects from sorafenib-induced cell death. In PC3 cells, Src and AKT are constitutively activated and targeted by sorafenib, leading to an increase in Bim protein levels. Overexpression of constitutively active AKT or knockdown of Bim protects PC3 cells from sorafenib-induced killing. In both PC3 and 22Rv1 cells, Mcl-1 depletion is required for the induction of cell death by sorafenib as transient overexpression of Mcl-1 is protective. Interestingly, co-culturing of primary cancer-associated fibroblasts (CAFs) with 22Rv1 or PC3 cells protected the cancer cells from sorafenib-induced cell death, and this protection was largely overcome by co-administration of the Bcl-2 antagonist, ABT737. In summary, the differential tyrosine kinase profile of prostate cancer cells defines the cytotoxic efficacy of sorafenib and this profile is modulated by CAFs to promote resistance. The combination of sorafenib with Bcl-2 antagonists, such as ABT737, may constitute a promising therapeutic strategy against prostate cancer

Expression and function of G-protein-coupled receptorsin the male reproductive tract

This review focuses on the expression and function of muscarinic acetylcholine receptors (mAChRs), α1-adrenoceptors and relaxin receptors in the male reproductive tract. The localization and differential expression of mAChR and α1-adrenoceptor subtypes in specific compartments of the efferent ductules, epididymis, vas deferens, seminal vesicle and prostate of various species indicate a role for these receptors in the modulation of luminal fluid composition and smooth muscle contraction, including effects on male fertility. Furthermore, the activation of mAChRs induces transactivation of the epidermal growth factor receptor (EGFR) and the Sertoli cell proliferation. The relaxin receptors are present in the testis, RXFP1 in elongated spermatids and Sertoli cells from rat, and RXFP2 in Leydig and germ cells from rat and human, suggesting a role for these receptors in the spermatogenic process. The localization of both receptors in the apical portion of epithelial cells and smooth muscle layers of the vas deferens suggests an involvement of these receptors in the contraction and regulation of secretion.Esta revisão enfatiza a expressão e a função dos receptores muscarínicos, adrenoceptores α1 e receptores para relaxina no sistema reprodutor masculino. A expressão dos receptores muscarínicos e adrenoceptores α1 em compartimentos específicos de dúctulos eferentes, epidídimo, ductos deferentes, vesícula seminal e próstata de várias espécies indica o envolvimento destes receptores na modulação da composição do fluido luminal e na contração do músculo liso, incluindo efeitos na fertilidade masculina. Além disso, a ativação dos receptores muscarínicos leva à transativação do receptor para o fator crescimento epidermal e proliferação das células de Sertoli. Os receptores para relaxina estão presentes no testículo, RXFP1 nas espermátides alongadas e células de Sertoli de rato e RXFP2 nas células de Leydig e germinativas de ratos e humano, sugerindo o envolvimento destes receptores no processo espermatogênico. A localização de ambos os receptores na porção apical das células epiteliais e no músculo liso dos ductos deferentes de rato sugere um papel na contração e na regulação da secreção.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de FarmacologiaUNIFESP, EPM, Depto. de FarmacologiaSciEL

Novel insights into the implication of the IGF-1 network in prostate cancer

Nearly a decade has passed since the hypothesis that the insulin-like growth factor (IGF) signalling cascade is involved in prostate carcinogenesis. Recent research has outlined the association of circulating IGF-1 and prostate cancer risk, and studies have elucidated the implication of the IGF network in the early stages of prostate carcinogenesis. Moreover, it has been suggested that IGF-1 induces ligand-independent activation of the androgen receptor and enhances the expression of matrix metalloproteinase-2 and urokinase plasminogen activator. Furthermore, progression to androgen independence has been linked to deregulation of the IGF-1-IGF-1-receptor axis. Here, we report on updated studies that contribute to the unravelling of the IGF ‘circuitry’ in prostate cancer cells, with the anticipation that relevant pharmacological ‘rewiring’ might offer novel therapeutic regimens

Hypertension, antihypertensive therapy, and erectile dysfunction

Erectile dysfunction represents a common problem in the male hypertensive population. Both erectile dysfunction and hypertension share common pathophysiologic pathways such as atherosclerosis and endothelial dysfunction. Furthermore, traditional cardiovascular risk factors affect both conditions. Notably, several antihypertensive medications seem to adversely affect erectile function whereas others may exert neutral or even favorable effects. Thus, the regular and meticulous clinical evaluation of hypertensive patients, as well as individualization of antihypertensive therapy, are important steps in the effective management of such patients. In addition, the administration of phosphodiesterase-5 inhibitors or apomorphine has excellent efficacy and safety profile in hypertensive patients irrespective of taking or not taking antihypertensive medications