Hif-1α/VEGF Pathway Activating Subjected To Hypoxia Mi-croenvironment In The Prostatic Stromal Cell Line Induces The Pathogenesis Of Benign Prostate Hyperplasia

Objective.Benign prostate hyperplasia(BPH)is one of the most common senile conditions affecting elder men,accompanied by rising prevalence with aging.Prostate is identified as the only benign organ appears to turn against atrophy and degeneration with aging,but show embryonic-reawakening reverse proliferation,ultimately lead to BPH.How does this pathological process develop and what is the trigger factor for the initiation of BPH?our previous studies revealed that hypoxia microenvironment was closely related to the prevalence of BPH,of which the activation of HIF-la was reckoned as a key factor.VEGF is the most important downstream gene of HIF-1α,which is directly related to tissue hypoxia tolerance and angiogenesis.But the specific mechanism of HIF-1α/VEGF signal pathway activation in the initiation and progression of BPH is unclear.The purpose of this study is to elucidate this problem and explore new therapeutic approaches for BPH.Materials and methods.We constructed HIF-lα gene overexpression/knockout prostatic stromal cell line WPMY-1 and prostatic epithelial cell line BPH-1 by lentivirus transfection,cultured under different conditions(hypoxia,normoxia and hypoxia+HIF-1α pathway inhibitors),the expression pattern of HIF-1α/VEGF pathway was detected by qPCR and Western blotting assay.Cell proliferation and apoptosis were analyzed by Cell Counting Kit-8(CCK-8)and flow cytometry.To further investigate the underline mechanism of the activation of HIF-1α/VEGF pathway in the pathological of BPH,our study resorted to miRWalk 2.0 database and western blotting to choose the targeting miRNA regulating HIF-1α expression,And the regulation role of the targeting miRNA was further verified by qPCR and the dual-luciferase assay.Results.In the prostatic stromal cell line WPMY-1,qPCR and western blotting results indicated that VEGF as the key downstream factor of HIF-1α,whose expression pattern was relatively consistent with HIF-1α.the expression of HIF-1α was activated under hypoxia microenvironment compared with normoxia condition,which was reversed by the HIF-la inhibitor.CCK-8,flow cytometry results indicated that the cells proliferation level of HIF-1α overexpressed group compared with HIF-1α knockdown group was upregulated and the cells apoptosis level was downregulated under hypoxia condition.And the HIF-la inhibitor could further depressed the cells proliferation and the promoted the cells apoptosis under hypoxia condition.However,the experimental results of the prostate epithelial cell line BPH-1 did not fully confirm the regulatory pattern of the HIF-1α/VEGF pathway and its activation role under hypoxia microenvironment.MiRWalk 2.0 database combined with Western blotting showed that mir-17-5p demonstrated the strongest inhibition effect on HIF-1α expression,which was determined as the target miRNA for further experimental verification.The results of qPCR and dual-luciferase assay indicated that the expression level of HIF-1α was significantly down-regulated after transfection with mir-17-5p mimics compared with the control group.Conclusion.The pathogenesis of BPH is mainly induced by the hyperplasia of prostatic stromal component.And the activation of HIF-1α/VEGF pathway in the prostatic stromal cell subjected to hypoxia microenvironment plays a significant role in the pathogenesis of BPH,which promotes cell proliferation,inhibits apoptosis and ultimately lead to BPH.Furthermore,this study indicated that the regulatory mechanism of this pathway may be related to the regulation of mir-17-5p on HIF-1α.