腺病毒介导融合双自杀基因治疗膀胱癌

目的 探讨腺病毒介导胞嘧啶脱氨酶（CD）和胸苷激酶（TK）融合双自杀基因系统对膀胱癌治疗作用并与单基因系统作比较。方法 利用含有CD-TK双自杀融合基因及绿色荧光蛋白（GFP）基因的复制缺陷腺病毒作载体，PCR检测CD、TK及E1基因。建立C57BL／6同系膀胱癌Mb49皮下移植瘤模型，观察肿瘤注射腺病毒联合丙氧鸟苷（GCV）或／和5-氟胞嘧啶（5-FC）治疗后肿瘤体积及组织学变化。结果 PCR可检测到腺病毒DNA中含CD及TK基因、无E1基因。腺病毒注射联合GCV、5-FC、GCV＋5-FC治疗后，肿瘤体积与对照组相比明显缩小（P=0.00），腺病毒注射联合GCV＋5-FC有协同作用（P=0．04），优于腺病毒注射联合GCV以及腺病毒注射5-FC。基因治疗后肿瘤细胞大片坏死．对照组细胞形态无变化。结论 腺病毒介导CD-TK融合双自杀基因联合GCV或／和5-FC能有效治疗膀胱癌，融合双自杀基因CD-TK／（GCV＋5-FC）系统对膀胱癌治疗有协同作用，其效果优于CD-TK／GCV或CD-TK／5-FC系统。

Adenovirus-mediated double suicide gene therapy for experimental bladder carcinoma

OBJECTIVE: To evaluate the feasibility and efficacy of cytocine deaminase-thymidine kinase (CD-TK) fusion double suicide gene therapy using adenovirus mediated CD-TK gene and green fluorescent rotein (GFP) gene combined with ganciclovir(GCV) or 5-flourocytosine(5-FC) in a murine subcutaneous bladder carcinoma model. METHODS: A replication defective adenovirus vector containing CD-TK gene was used. Subcutaneous tumors were established in syngenic C57BL/6 female mice with 1 x 10(6) Mb49 cells. Intratumoral injection of AdCD-TK (1.58 x 10(8) PFU, qd x days) in combination with GCV (40 mg.kg(-1).d(-1), ip, qd x 10 days) or 5-FC (400 mg.kg(-1).d(-1), ip, qd x 10 days) was administered in vivo for the determination of treatment efficacy in separate controlled experiments. RESULTS: In vivo experiments demonstrated that the mean volume of tumor in the group of AdCD-TK/GCV(326.58+/-109.56 mm(3)), AdCD-TK/5-FC (235.33+/-62.94 mm(3)) and AdCD-TK/(GCV+5-FC) (23.58+/-6.78 mm(3)) was reduced significantly compared with that of control group (993.51+/-158.32 mm(3)) (P=0.00), the mean volume of tumor in the group of AdCD-TK/(GCV+5-FC) was significantly less than that in the group of AdCD-TK/GCV or AdCD-TK/5-FC (P=0.04). Tumor necrosis was revealed by histomorphology compared with control animals. CONCLUSIONS: Adenovirus mediated CD-TK double suicide gene combining with GCV or 5-FC could provide an effective therapy in an experimental murine bladder carcinoma by significantly inhibiting tumor growth. The treatment efficacy of AdCD-TK combining GCV and 5-FC was superior to that of AdCD-TK combining GCV or AdCD-TK combining 5-FC.