Su Z Z, Leon J A, Jiang H, Austin V N, Zimmer S G, Fisher P B
Department of Pathology, Columbia University, College of Physicians and Surgeons, New York, New York 10032.
Cancer Res. 1993 Apr 15;53(8):1929-38.
Transformation of cloned rat embryo fibroblast (CREF) cells with the host-range adenovirus type 5 (Ad5) mutant, H5hr1, results in transformants with a fibroblastic morphology which displays a cold-sensitive transformation phenotype and oncogenic potential in both nude mice and syngeneic rats. In contrast, wild-type (wt) Ad5 transformed CREF cells are epithelioid in morphology, temperature independent for transformation, and nontumorigenic. The present studies were conducted to analyze the contribution of the mutated E1A and E1B regions of H5hr1 in regulating the biological properties of H5hr1-transformed CREF cells. CREF cells were constructed which contain the mutated E1A and E1B transforming regions of H5hr1 and either a wt Ad5 E1A gene, a wt Ad5 E1B gene, or both a wt Ad5 E1A and a wt E1B gene. A wt Ad5 E1A gene was sufficient in reversing the cold-sensitive transformation phenotype. By using a wt Ad5 E1A gene under the transcriptional control of a dexamethasone-inducible mouse mammary tumor virus promoter, a direct suppressive effect of wt Ad5 E1A on colony formation in monolayer culture and agar growth of H5hr1-transformed cells was demonstrated. Expression of a wt Ad5 E1A, a wt Ad5 E1B, or both wt transforming genes in H5hr1-transformed CREF cells also suppressed oncogenicity. The ability or inability to form tumors in animals was found not to correlate with sensitivity to natural killer cell-mediated lysis. These results indicate that both the wt Ad5 E1A and wt Ad5 E1B genes can function as dominant suppressors of the oncogenic process when coexpressed in H5hr1-transformed CREF cells. This effect does not require large quantities of wt Ad5 E1A or E1B transforming proteins, nor is it directly related to the acquisition of a natural killer cell cytolysis-susceptible phenotype.
用宿主范围的腺病毒5型（Ad5）突变体H5hr1转化克隆的大鼠胚胎成纤维细胞（CREF），会产生具有成纤维细胞形态的转化体，该转化体在裸鼠和同基因大鼠中均表现出冷敏感转化表型和致癌潜力。相比之下，野生型（wt）Ad5转化的CREF细胞形态呈上皮样，转化不受温度影响，且无致瘤性。本研究旨在分析H5hr1突变的E1A和E1B区域在调节H5hr1转化的CREF细胞生物学特性中的作用。构建了含有H5hr1突变的E1A和E1B转化区域以及野生型Ad5 E1A基因、野生型Ad5 E1B基因或野生型Ad5 E1A和野生型E1B基因的CREF细胞。野生型Ad5 E1A基因足以逆转冷敏感转化表型。通过使用在地塞米松诱导的小鼠乳腺肿瘤病毒启动子转录控制下的野生型Ad5 E1A基因，证明了野生型Ad5 E1A对H5hr1转化细胞单层培养中的集落形成和琼脂生长具有直接抑制作用。在H5hr1转化的CREF细胞中表达野生型Ad5 E1A、野生型Ad5 E1B或两个野生型转化基因也能抑制致癌性。发现动物中形成肿瘤的能力或无能力与对自然杀伤细胞介导的裂解的敏感性无关。这些结果表明，当在H5hr1转化的CREF细胞中共表达时，野生型Ad5 E1A和野生型Ad5 E1B基因均可作为致癌过程的显性抑制剂。这种作用不需要大量的野生型Ad5 E1A或E1B转化蛋白，也与获得对自然杀伤细胞溶解敏感的表型没有直接关系。
