Hei T K, Piao C Q, Willey J C, Thomas S, Hall E J
Center for Radiological Research, College of Physicians and Surgeons, Columbia University, New York, NY.
Carcinogenesis. 1994 Mar;15(3):431-7. doi: 10.1093/carcin/15.3.431.
Epidemiological studies have shown that inhalation of radon is associated with an increased risk for bronchogenic carcinoma in uranium miners. These alpha-emitting radon daughters also represent the largest component of background radiation to the general public. In the present study, the oncogenic transforming effects of single versus multiple doses of radon-simulated alpha-particles were examined using human papillomavirus-immortalized human bronchial epithelial cells. Endpoints such as growth kinetics, resistance to serum and 12-O-tetradecanoylphorbol-13-acetate-induced terminal differentiation, anchorage-independent growth and tumorigenicity in nude mice were used to assess the various stages of transformation in the bronchial epithelial cells. We show here, for the first time, that immortalized human cells in culture can be malignantly transformed by a single 30 cGy dose of alpha-particles. Transformed cells produced progressively growing subcutaneous tumors upon inoculation into athymic nude mice. Immunofluorescent staining of keratin and isozyme analysis of the cell lines subsequently generated from these tumors indicated that the cells were of human epithelial origin. Analysis of genomic DNA from the tumorigenic cell lines using PCR amplification and restriction enzyme analysis demonstrated no point mutation at either codon 12/13 or 61 in any of the ras oncogenes examined (K-, N- and H-ras). This system provides an opportunity to study the cellular and molecular changes at the various stages in radiation carcinogenesis involving human cells.
流行病学研究表明，吸入氡气与铀矿矿工患支气管癌的风险增加有关。这些发射α粒子的氡子体也是公众背景辐射的最大组成部分。在本研究中，使用人乳头瘤病毒永生化的人支气管上皮细胞，研究了单剂量与多剂量氡模拟α粒子的致癌转化作用。采用生长动力学、对血清的抗性以及12-O-十四烷酰佛波醇-13-乙酸酯诱导的终末分化、不依赖贴壁生长和裸鼠致瘤性等终点指标，评估支气管上皮细胞转化的各个阶段。我们首次在此表明，培养中的永生化人类细胞可被单次30 cGy剂量的α粒子恶性转化。将转化细胞接种到无胸腺裸鼠体内后，会产生逐渐生长的皮下肿瘤。对随后从这些肿瘤中产生的细胞系进行角蛋白免疫荧光染色和同工酶分析表明，这些细胞起源于人类上皮细胞。使用PCR扩增和限制性酶切分析对致瘤细胞系的基因组DNA进行分析，结果显示在所检测的任何ras癌基因（K-ras、N-ras和H-ras）的第12/13或61密码子处均未发现点突变。该系统为研究涉及人类细胞的辐射致癌作用各个阶段的细胞和分子变化提供了一个机会。
