Kao C, Huang J, Wu S Q, Hauser P, Reznikoff C A
University of Wisconsin, Department of Biochemistry, Madison.
Carcinogenesis. 1993 Nov;14(11):2297-302. doi: 10.1093/carcin/14.11.2297.
In the present study, we examined the sufficiency of SV40 T antigen (Tag) binding to pRB and p53 to substitute for alterations in RB and TP53 at all stages of human uroepithelial cell (HUC) transformation in vitro. Two independent SV40 immortalized HUCs (SV-HUC and SV-HUC/CK2) and 17 independent derivative carcinogen-induced or spontaneous tumors (T-SV-HUCs and T-SV-HUC/CK2) representing different stages of urothelial tumorigenesis were examined. Although five of 17 T-SV-HUCs and SV-HUC/CK2 and its derivative tumor showed 13q chromosome deletion and loss of heterozygosity (LOH), this did not reflect functional loss of pRB because Tag/pRB binding was unaltered and sequencing showed a normal RB gene in all these tumors. No genetic alterations involving 17p or TP53 were detected in any tumors in this study using the same techniques. These results indicate that Tag/pRB and Tag/p53 binding apparently abrogate requirements for/or a selective advantage of RB and TP53 mutations in HUC tumorigenic transformation and progression, as well as in HUC immortalization. These data also provide new evidence that more than one suppressor gene may be located on chromosome 13q.
在本研究中，我们检测了猴空泡病毒40 T抗原（Tag）与视网膜母细胞瘤蛋白（pRB）和p53的结合是否足以替代体外人尿路上皮细胞（HUC）转化各阶段中RB和TP53的改变。我们检测了两个独立的经猴空泡病毒40永生化的HUC（SV-HUC和SV-HUC/CK2）以及17个独立的衍生致癌物诱导或自发肿瘤（T-SV-HUCs和T-SV-HUC/CK2），它们代表尿路上皮肿瘤发生的不同阶段。尽管17个T-SV-HUCs中的5个以及SV-HUC/CK2及其衍生肿瘤显示出13号染色体缺失和杂合性缺失（LOH），但这并未反映pRB的功能丧失，因为Tag/pRB结合未改变，且测序显示所有这些肿瘤中的RB基因均正常。使用相同技术，本研究中在任何肿瘤中均未检测到涉及17号染色体短臂或TP53的基因改变。这些结果表明，Tag/pRB和Tag/p53结合显然消除了HUC致瘤转化和进展以及HUC永生化过程中对RB和TP53突变的需求或选择性优势。这些数据还提供了新的证据，表明13号染色体上可能存在不止一个抑癌基因。
