全反式维甲酸增强雄激素非依赖性前列腺癌自杀基因治疗旁观者效应的实验研究

AII-trans retinoic acid enhances the bystander effect of suicide gene against androgen-unresponsive prostate cancer cell line

目的 探讨全反式维甲酸（ATRA）对腺病毒为载体的单纯疱疹病毒胸苷激酶（Ad-TK）／N氧鸟苷（GCV）治疗激素非依赖性前列腺癌旁观者效应的影响及其机理。方法 采用免疫细胞化学和Western blot方法检测ATRA作用前后前列腺癌细胞株PC-3表达连接蛋白（Cx）43的水平和位置，应用MTT法检测细胞存活率，观察ATRA处理前后Ad—TK／GCV系统治疗PC-3细胞旁观者效应的变化。结果 PC-3细胞弱表达Cx43，总体表达率为27．7％；在浓度〉1×10^-6mol／L的ATRA作用下，Cx43水平表达阳性率达75．7％，以胞膜表达为主，明显高于ATRA处理前（P〈0．05）。在达到明显旁观者效应（细胞生存率50％）时，Ad—TK／GCV系统组需要TK^＋PC-3细胞数为50％，而ATRA联合Ad—TK／GCV系统组需要TK^＋PC-3细胞数仅为30％，二者比较差异有统计学意义（P〈0．05）。结论 前列腺癌Ad—TK／GCV治疗的旁观者效应与Cx43表达及定位有关，AT—RA可以通过提高Cx43的表达增强旁观者效应。

Objective To investigate the bystander effect of all-trans retinoic acid on the recombinant of adenovirus and herpes simplex virus thymidine kinase（Ad-TK）/ganciclover（GCV） system in the treatment of androgen-unresponsive prostate cancer cell line. Methods Immunocytochemistry and Western blot were used to analyze the expression and location of Connexin（Cx）43 in PC-3 cells before and after treatment with ATRA; meanwhile, the bystander-effect of Ad-TK/GCV against PC-3 cells was determined by the cells growth inhibitory rate with methyl thiazolyl tetrazolium（MTT）. Results The expression of Cx43 was low （27.7%） in PC-3 cells, but increased （75.7%） and located mainly on the membrane after treatment with ATRA （over 10^-6 mol/L）. Compared with using AdTK/GCV system only, ATRA could augment significantly the bystander effect of Ad-TK/GCV system which was showed by reducing the ratio of TK positive PC-3 cells from 50% to 30%（P〈0.05）. Conclusions In the treatment of prostate cancer, there is relationship between Cx43 expression and location and Ad-TK/GCV bystander effect. ATRA could up-regulate the expression of Cx43 and thereby enhance the bystander effect.