PAWR-MSCs介导前列腺癌细胞靶向杀伤及紫杉醇增敏的分子机制

There is currently no cure for androgen independent prostate cancer (AIPC). It is urgent to develop new molecularly targeted drugs of potential clinical value. In our previous study, human MSCs were isolated and transfected with a lentivirus vector encoding full-length human PAWR. It was observed that MSCs secreting PAWR protein have the targeting cytotoxicity to prostate cancer cell line DU145, and could increase the susceptibility of paclitaxel resistant prostate cancer cell line. But the exact mechanism of these phenomenons is unclear. Therefore, based upon our previous results, the present study was designed. Primary prostate cancer cells were isolated and cultured, and were used to establish subcutaeous xenograft model of human prostate cancer in nude mice. PAWR-MSCs and the supernatant were injected into the nude mice with prostate cancer by caudal vein. Growth curves and the weight of the tumor were observed. The tumorigenicity ability and the inhibition rate of tumor were evaluated in nude mice models. GeneChip was also used to detect the changes of apoptosis regulatory protein and molecule of signal pathway in prostate cancer cells induced by PAWR-MSCs in the transcriptional level. Membrane and endoplasmic reticulum proteins were isolated, and GST-Pulldown technology was used to explore the molecule interacting directly with PAWR. Based on these results, we will elucidate the roles of PAWR in apoptosis associated with endoplasmic reticulum stress in prostate cancer cells, which will provide theoretical proofs for elucidating the mechanism by which prostate cancer cell become resistant to paclitaxel and developing new molecular targets.

控制雄激素非依赖性前列腺癌的进展十分困难，迫切需要探索新的治疗方法。前期体外研究发现分泌表达PAWR的MSCs能特异性杀伤前列腺癌细胞，增加紫杉醇耐药株细胞对紫杉醇的敏感性，具体机制不明。我们以前列腺癌细胞DU145为研究对象，观察PAWR-MSCs靶向杀伤DU145细胞及逆转紫杉醇耐药株对紫杉醇耐药的情况；随后，建立裸鼠原代前列腺癌移植瘤模型，注射PAWR-MSCs，以肿瘤生长曲线与瘤重观察裸鼠成瘤能力的变化，计算抑瘤率；最后，通过基因芯片技术在转录水平检测PAWR-MSCs诱导下凋亡相关调控蛋白及信号通路分子，分离膜蛋白和内质网蛋白，结合GST-Pulldown技术寻找PAWR的直接作用分子，阐明PAWR在前列腺癌内质网应激性细胞凋亡中的分子机制，丰富PAWR分子参与前列腺癌细胞凋亡调控的分子机制，为阐明前列腺癌细胞紫杉醇耐药的分子机制奠定基础，为探索前列腺癌靶向治疗策略提供实验依据。

前列腺癌是男性高发的恶性肿瘤之一，目前对激素抵抗性前列腺癌缺乏有效的治疗手段。PAWR是一个抑癌基因，通过与细胞表面的GRP78分子作用诱导肿瘤细胞凋亡。人间充质干细胞可以特异性迁移至肿瘤部位，是理想的基因治疗载体。本项目以前列腺癌雄激素非依赖细胞系DU145和裸鼠原代前列腺癌移植瘤模型为研究对象，证实表达PAWR基因的间充质干细胞（PAWR-MSCs）可以抑制前列腺癌细胞增殖、克隆形成，引起细胞凋亡，抑制肿瘤生长，提高前列腺癌细胞对紫杉醇的敏感性；发现了PAWR-MSCs通过提高P53的活性，降低survivin的表达从而发挥上述功能；联合PAWR-MSCs与紫杉醇有效抑制TRAMP前列腺癌小鼠肿瘤生长，为临床治疗提供了理论基础。