膀胱灌注逆转录病毒载体HSV-TK基因治疗大鼠膀胱癌

目的：研究膀胱内灌注逆转录病毒载体单纯疱疹病毒胸腺嘧啶核苷激酶(HSVtk)基因治疗膀胱癌的作用。方法：用N-甲基-亚硝基脲(MNU)膀胱灌注诱导建立大鼠原位膀胱肿瘤模型，该肿瘤与人类膀胱肿瘤病理特点非常相似。随后经尿道膀胱灌注逆转录病毒载体HSV-TK(基因，腹腔内注射羟基无环鸟苷(ganciclovir，GCV)，连续6天。结果：经尿道膀胱灌注逆转录病毒HSV-TK基因后48小时RTPCR检测出膀胱肿瘤中HSV-TK基因表达。GCV处理后．肿瘤体积以及膀胱总重量检测表明膀胱肿瘤的生长被显著抑制。肿瘤细胞DNA电泳显示诱导凋亡可能是HSV-TK／GCV系统治疗肿瘤的重要机制。结论：经尿道膀胱灌注重组逆转录病毒载体可以向肿瘤转导HSV—TK基因。HSV-TK／GCV系统能抑制鼠原位膀胱肿瘤的生长。

HSV - TK- gene therapy for an Orthotopic Rat Bladder Tumor Entailing Instillation of Retroviral Vectors

Objective To study the curative effict of an intravesical HSV-TK suicide gene therapy protocol making use of aretroviral vector on bladder cancer.Method Bladder tumors,which were histologically similar to the human bladder cancer,were in-duced in rats by intravesical administration of MNU(N-mmethyl-noitrosourea).The therapeutic protocol then entailed instillationof a retroviral vector containing the HSV-TK suicide gene into rat bladder and was followed by a 6-day-term regimen of in-traperitoneal injection of ganciclovir(GCV).Results RT-PCR performed 48 hours after intravesical instillation of retroviral vectorrevealed the expression of HSV-TK in the bladder tumor.The examination of tumor volume and total bladder weight after a 6-day-term GCV regimen showed that the growth of the bladder tumor was significantly inhibited.Electrophoresis of the tumor cell DNAextraction proved that the apoptosis of the tumor cells might be the important mechanism of treating the tumor with HSV-TK/GCVsystem.Conclusion Suicide-gene therapy using retroviral vector-mediated HSV-TK/GCV provides an effective method for treat-ing the experimental murine orthotopic bladder cancer by significantly inhibiting tumor growth.