Mason Douglas X, Keppler Daniel, Zhang Jun, Jackson Tonya J, Seger Yvette R, Matsui Seiichi, Abreo Fleurette, Cowell John K, Hannon Gregory J, Lowe Scott W, Lin Athena W
Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
Carcinogenesis. 2006 Feb;27(2):350-9. doi: 10.1093/carcin/bgi264. Epub 2005 Nov 9.
In contrast to rodent cells, normal human fibroblasts are generally resistant to neoplastic transformation in vitro. Here, we report the derivation and characterization of a spontaneously transformed cell line from normal human IMR90 fibroblasts transduced with E1A and Ras oncogenes. Unlike the parental, non-tumorigenic E1A/Ras-expressing IMR90 cells, these spontaneously transformed cells displayed aberrant growth potential in vitro and were capable of tumorigenesis in vivo. In contrast to the parental E1A/Ras-expressing cells, both the spontaneously transformed cells and cells derived from resultant tumors displayed specific t(7q;8q) and t(5q;17) structural chromosomal changes. Chromosome 8q contains c-Myc, which is capable of activating the telomerase catalytic subunit hTERT. Notably, upregulation of c-Myc, hTERT and telomerase activity were detected only in the tumorigenic cells. Transduction of Myc siRNA into the tumorigenic cells led to a concomitant downregulation of hTERT. Furthermore, transduction of Myc or hTERT into the non-tumorigenic E1A/Ras-expressing IMR90 cells was able to confer tumorigenesis on these cells. These studies suggest that the t(7;8) translocation may result in Myc overexpression and its subsequent activation of hTERT, which may contribute to the tumorigenicity of the IMR90 cells. Furthermore, this report describes additional successful neoplastic transformation of human IMR90 fibroblasts by defined genetic elements. The spontaneously transformed cells we have derived provide a valuable model system for the study of neoplastic transformation.
与啮齿动物细胞不同，正常人成纤维细胞在体外通常对肿瘤转化具有抗性。在此，我们报告了从用E1A和Ras癌基因转导的正常人IMR90成纤维细胞中获得的自发转化细胞系的衍生和特性。与亲本的、无致瘤性的表达E1A/Ras的IMR90细胞不同，这些自发转化细胞在体外表现出异常的生长潜能，并且在体内具有致瘤能力。与亲本表达E1A/Ras的细胞相比，自发转化细胞和源自所得肿瘤的细胞均显示出特定的t(7q;8q)和t(5q;17)结构染色体变化。8号染色体q臂包含c-Myc，其能够激活端粒酶催化亚基hTERT。值得注意的是，仅在致瘤性细胞中检测到c-Myc、hTERT和端粒酶活性的上调。将Myc siRNA转导至致瘤性细胞中导致hTERT的相应下调。此外，将Myc或hTERT转导至无致瘤性的表达E1A/Ras的IMR90细胞中能够赋予这些细胞致瘤性。这些研究表明，t(7;8)易位可能导致Myc过表达及其随后对hTERT的激活，这可能有助于IMR90细胞产生致瘤性。此外，本报告描述了通过特定遗传元件对人IMR90成纤维细胞进行的额外成功的肿瘤转化。我们获得的自发转化细胞为肿瘤转化研究提供了有价值的模型系统。
