Gene Therapy for Bladder Tumor using HSV-tk/GCV System

肿瘤基因治疗在基础和临床领域都得到了广泛的研究。我们利用BBN诱导的大鼠膀胱肿瘤对腺病毒基因治疗的效果进行了检测。将携带LacZ基因的重组腺病毒载体注入大鼠膀胱，对肿瘤有明显的基因转移优势。正常膀胱X-Gal染色后仅见少量蓝色斑点。膀胱肿瘤组织中可见弥漫的深蓝色染色。我们推测糖胺多聚糖(GAG)可能对这种优先基因转移有反应。为了去除膀胱粘膜上的堵塞，我们用盐酸冲洗膀胱。然后灌注腺病毒载体(Ad.CAG.lacZ)。正常膀胱经盐酸冲洗后呈浓蓝色，呈肿瘤样。能检测到GAG的Alsian蓝染色显示肿瘤和盐酸洗涤的正常膀胱表面都有GAG的架子。这些结果表明，肿瘤表面的GAG通过滴注腺病毒载体诱导了基因的优先转移。接下来，我们用同样的方法诱导HSV-tk基因进入膀胱肿瘤。更昔洛韦序贯治疗组肿瘤体积较对照组明显缩小。BBN诱导的大鼠膀胱癌与人浅表性膀胱癌非常相似。我们的实验表明，体内基因转移的优势在于腺病毒载体的简单滴注。HSV-tk/GCV实验显示，抑制肿瘤生长或缩小肿瘤体积具有明显的抗肿瘤作用。这些数据对人体临床试验非常重要。

Cancer gene therapy is extensively studied in both basic and clinical field. We examined efficacy of adenoviral gene therapy using BBN induced rat bladder tumor. Instillation of adenoviral vector carrying lacZ gene to rat bladder showed preferential gene transfer to tumor. Normal bladder showed only small blue spots after X-gal staining. Diffuse and strong blue staining was observed in bladder tumor. We speculated glycosaminoglycan (GAG) might respond to this preferential gene transfer. To remove GAG on bladder mucosa, we wash bladder with Hcl. Then we instilled adeno viral vector (Ad. CAG.lacZ). After washing bladder with HCl, normal bladder was stained blue strongly like as tumor. Alsian blue staining which could detect GAG revealed rack of GAG on both tumor and HCl washed normal bladder surface. These data indicated that rack of GAG on tumor surface induced preferential gene transfer by instillation of adenoviral vector.We next induced HSV-tk gene to bladder tumor using same method. Sequential treatment with ganciclovir caused marked size reduction of tumor compare to control group. BBN induced rat bladder tumor is very resemble to human superficial bladder tumor. Our experiments showed preferential in vivo gene transfer simple instillation of adenoviral vector. HSV-tk/GCV experiments showed marked anti tumor effect due to growth inhibition or size reduction of tumors. These data were very important to human clinical trial.