缺氧诱导因子1α诱导前列腺癌LNCaP细胞上皮间质转化的体内外研究

目的:探讨在体内外环境下缺氧诱导因子1α(HIF-1α)过表达对前列腺癌细胞发生上皮间质转化(EMT)并导致肿瘤侵袭能力升高的影响。方法:对已构建的稳定表达HIF-1α的人前列腺癌LNCaP细胞(LN-CaP/HIF-1α)复苏后培养,对HIF-1α过表达进行鉴定。MTT法测定细胞增殖;检测转染前后培养液上清PSA水平;软琼脂成瘤实验比较两种细胞体外成瘤能力;将转染前后的LNCaP细胞注射免疫裸鼠皮下建立皮下肿瘤模型,观察肿瘤生长情况;收集肿瘤标本进一步行免疫组化处理。结果:免疫荧光和Western印迹证实LNCaP/HIF-1α细胞中HIF-1α过表达。同LNCaP细胞相比,转染HIF-1α的人前列腺癌LNCaP细胞培养液中PSA水平明显降低;MTT法显示其更具有增殖活性,体外成瘤能力更强。体内实验显示皮下肿瘤成瘤率提高,成瘤时间提前。肿瘤标本免疫组化提示转染组E钙粘蛋白表达下调,波形蛋白表达上调。结论:HIF-1α过表达能够封闭E钙粘蛋白,上调波形蛋白表达,提示HIF-1α过表达可能通过诱导EMT增强LNCaP细胞侵袭能力。

Over-expression of hypoxia-inducible factor-1alpha induces epithelial-mesenchymal transition in LNCaP cells in vitro and in vivo

Objective: To investigate the effects of the over-expression of hypoxia-inducible factor-1α(HIF-1α) on the epithelial-mesenchymal transition(EMT) and invasive potency of LNCaP cells in vitro and in vivo.Methods: We cultured LNCaP cells stably expressing HIF-1α(LNCaP/HIF-1α) and LNCaP cells,identified the over-expression of HIF-1α,determined the proliferation of the two cell lines by MTT assay and the level of PSA in the supernatant of culture medium,and detected the anchorage independent growth by soft-agar colony formation assay.A subcutaneous tumor model was established in nude mice by injecting LNCaP/HIF-1α and LNCaP cells followed by observation of the tumor growth.Tumor specimens were obtained for immunohistochemistry.Results: The over-expression of HIF-1α was confirmed in the LNCaP/HIF-1α cells by immunofluorescence staining and Western blotting.The level of PSA was obviously decreased in LNCaP/HIF-1α as compared with that in LNCaP cells.MTT assay identified the increased proliferation of LNCaP/HIF-1α cells.The cell colony forming ability of the LNCaP cells was significantly lower than that of the LNCaP/HIF-1α cells.The rate of tumorigenesis was increased and its time shortened in the LNCaP/HIF-1α group.Immunohistochemistry revealed an up-regulated expression of vimentin and a down-regulated expression of E-cadherin in the tumor specimens.Conclusion: The over-expression of HIF-1α can up-regulate the expression of vimentin and down-regulate the expression of E-cadherin,which may enhance the invasive potency of LNCaP cells by inducing EMT.