The Function And Molecular Mechanism Of MiR186 In The Prostate Cancer Progression

Prostate cancer(PCa)has become the most frequently diagnosed cancer and the second leading cause of cancer-related deaths in men in western countries.Metastatic PCa remains the main cause of PCa-related death in men,more than half advanced prostate cancer can spread to other parts of body.There are emerging evidences that chronic inflammation can initialize PCa and promote its development.In the first part,we established two cellular transformation model BPH1/LT-BPH1 and P69/M12,and performed high-throughput sequencing and real-time PCR to profile the mi RNAs expression.Among these candidate mi RNAs,mi R186 was significantly reduced in the transformed LT-BPH1 and M12 cells.Function experiments revealed that mi R186 dramatically suppressed Epithelial-to-Mesenchymal Transition(EMT),cell proliferation,migration and invasion in vivo and in vitro through downregualting its target gene Twist1.Furthermore,we investigated the clinical significance of their expression levels in the prostate cancer patients.The expression levels of mi R186 were significantly decreased in prostate tumor specimens,especially in the metastatic patients,and negative correlation with the clinical stages and histological grades.Moreover,patients with high mi R186 expression levels had a higher survival rate.On contrary,the expression levels of Twist1 were markedly increased in prostate tumor specimens.Moreover,the statistical correlation analysis revealed a notably negative correlation between mi R186 and Twist1.These results revealed the potential application value of mi R186 and Twist1 in the early diagnosis,treatment,and prognosis of PCa.In the second part,we found that mi R186 was a new inflammatory response factor and was induced under inflammatory stimulation.We also demonstrated that the induction of mi R186 by inflammatory stimulation was NF-?B/p65 dependent and the activated NF-?B/p65 by inflammatory stimulation promoted mi R186 transcription by directly binding to the mi R186 promotor.Moreover,we demonstrated that Twist1,which was the downstream target of mi R186,formd a novel negative feedback loop to regulate mi R186 through recruiting the enzymatically active Dnmt3 a to the promotor of mi R186,which facilitated the site-specific Cp G methylation(CG6~10)to decrease the binding and the transcriptional activity of NF-?B/p65 on the mi R186 promoter,The proposed ‘NF-?B/p65-mi R186-Twist1/Dnmt3a' pathway may involve in the progression of inflammation-associated PCa.