Hei T K, Wu L J, Piao C Q
Center for Radiological Research, Vanderbilt Clinic, College of Physicians & Surgeons of Columbia University, New York, NY 10032, USA.
Environ Health Perspect. 1997 Sep;105 Suppl 5(Suppl 5):1085-8. doi: 10.1289/ehp.97105s51085.
Although asbestos is a well-established lung carcinogen, there currently is no suitable human cell model in which to examine the underlying cellular and molecular changes associated with fiber-mediated bronchial carcinogenesis. Using a recently established transformation model based on a human papillomavirus-immortalized human bronchial epithelial cell line, we successfully transformed these BEP2D cells after a single, 7-day treatment with a 20-microgram/ml (4 micrograms per cm2 area) dose of Union Internationale Contre le Cancer (UICC) Rhodesian chrysotile fibers. Asbestos treatment resulted in a surviving fraction of 0.18 compared to control cells. Transformed cells developed through a series of sequential steps, including altered growth kinetics, resistance to serum-induced terminal differentiation, and anchorage-independent growth, before becoming tumorigenic to form progressively growing tumors in nude mice. Seven tumorigenic cell lines were isolated and determined to be of human epithelial origin based on immunofluorescent staining of keratin and isozyme analysis. Analysis of tumor DNA revealed no mutations at either codon 12 or 13 in any the ras oncogenes. An independent role for K-ras mutation in fiber carcinogenesis, therefore, cannot be confirmed. This model provides a unique opportunity to study the cellular and molecular changes at the various stages in fiber-mediated neoplastic transformation of human bronchial epithelial cells.
尽管石棉是一种公认的肺癌致癌物，但目前尚无合适的人类细胞模型来研究与纤维介导的支气管癌发生相关的潜在细胞和分子变化。我们使用一种最近建立的基于人乳头瘤病毒永生化的人支气管上皮细胞系的转化模型，用20微克/毫升（每平方厘米面积4微克）剂量的国际癌症研究机构（UICC）罗德西亚温石棉纤维对这些BEP2D细胞进行单次7天处理后，成功地使其发生了转化。与对照细胞相比，石棉处理后的存活分数为0.18。转化细胞经过一系列连续步骤发展而来，包括生长动力学改变、对血清诱导的终末分化产生抗性以及不依赖贴壁生长，之后才具有致瘤性，能在裸鼠体内形成逐渐生长的肿瘤。我们分离出7个致瘤细胞系，并通过角蛋白免疫荧光染色和同工酶分析确定它们起源于人类上皮细胞。对肿瘤DNA的分析显示，任何一个ras癌基因的第12或13密码子均未发生突变。因此，无法证实K-ras突变在纤维致癌过程中具有独立作用。该模型为研究人类支气管上皮细胞在纤维介导的肿瘤转化各个阶段的细胞和分子变化提供了独特的机会。
