MicroRNAs have been implicated in regulating diverse cellular pathways. Emerging evidence indicates that miR-143 plays causal roles in cancer tumorigenesis as a tumor suppress gene; however, its role in prostate cancer tumorigenesis remains largely unknown. The aims of this study were to verify the effect of miR-143 on proliferation and migration abilities of prostate cancer cells. The expression level of miR-143 and its target gene KRAS were measured by realtime PCR and western blotting, respectively. Effects of miR-143 in cell proliferation, migration and chemosensitivity were evaluated by MTT assay, FACS cell cycle analysis, colony formation assay, and transwell migratory assay. Our results revealed an inverse correlation of expression between miR-143 and KRAS protein in prostate cancer samples (Pearson's correlation scatter plots: R = -0.707, P < 0.05). Moreover, over-expression of miR-143 in prostate cancer cells suppressed their proliferation and migration and increased their sensitivity to docetaxel by targeting EGFR/RAS/MAPK pathway. These findings suggest that miR-143 plays an important role in prostate cancer proliferation, migration and chemosensitivity by suppressing KRAS and subsequent inactivation of MAPK pathway, which provides a potential development of a new approach for the treatment of prostate cancer.

Our findings suggest that ubiquitous loss of miR-146a is a critical mechanism for overexpression of EGFR in CRPC, which is crucial to better understanding the pathogenesis of CRPC.

BackgroundAbnormal germline DNA methylation in males has been proposed as a possible mechanism compromising spermatogenesis of some men currently diagnosed with idiopathic infertility. Previous studies have been focused on imprinted genes with DNA methylation in poor quality human sperms. However, recent but limited data have revealed that sperm methylation abnormalities may involve large numbers of genes or shown that genes that are not imprinted are also affected.Methodology/Principal FindingsUsing the methylation-specific polymerase chain reaction and bisulfite sequencing method, we examined methylation patterns of the promoter of methylenetetrahydrofolate reductase (MTHFR) gene (NG_013351: 1538–1719) in sperm DNA obtained from 94 idiopathic infertile men and 54 normal fertile controls. Subjects with idiopathic infertility were further divided into groups of normozoospermia and oligozoospermia. Overall, 45% (41/94) of idiopathic infertile males had MTHFR hypermethylation (both hemimethylation and full methylation), compared with 15% of fertile controls (P<0.05). Subjects with higher methylation level of MTHFR were more likely to have idiopathic male infertility (P-value for trend  = 0.0007). Comparing the two groups of idiopathic infertile subjects with different sperm concentrations, a higher methylation pattern was found in the group with oligozoospermia.ConclusionsHypermethylation of the promoter of MTHFR gene in sperms is associated with idiopathic male infertility. The functional relevance of hypermathylation of MTHFR to male fertility warrants further investigation.