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有广泛的研究。我们使用BBN诱导的大鼠膀胱肿瘤检测腺病毒基因治疗的功效。腺病毒载体介导的lacZ基因转染大鼠膀胱后，可优先转移至肿瘤。正常膀胱经X-gal染色后仅显示小的蓝色斑点。膀胱肿瘤呈弥漫性强蓝色染色。我们推测糖胺聚糖（GAG）可能会响应这种优先基因转移。为了去除膀胱粘膜上的GAG，我们用盐酸冲洗膀胱。然后将腺病毒载体（Ad. lacZ）。用盐酸冲洗膀胱后，正常膀胱呈蓝色，与肿瘤相似。Alsian blue染色可检测GAG，在肿瘤和盐酸冲洗的正常膀胱表面均可见GAG条带。这些数据表明，肿瘤表面的GAG支架通过滴注腺病毒载体诱导了优先的基因转移，我们接下来用同样的方法将HSV-tk基因导入膀胱肿瘤。与对照组相比，更昔洛韦序贯治疗使肿瘤体积显著缩小。BBN诱发的大鼠膀胱肿瘤与人浅表性膀胱肿瘤非常相似。我们的实验表明，优先在体内基因转移腺病毒载体简单滴注。HSV-tk/GCV实验显示了显著的抗肿瘤作用，这是由于肿瘤生长抑制或肿瘤体积减小。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.