ISOLATION OF GENES FROM RADIATION TRANSFORMED CELLS

电离辐射是一种致癌物质，可诱发人类恶性肿瘤， 动物模型系统。 据了解，它有潜力参与 癌症发展的多步骤过程中的许多点。 这种多步骤 过程反映了从正常到启动的细胞进化， 癌前和恶变前转化为肿瘤和恶性细胞。 我们有 最近证实了在人类细胞中诱导恶性表型 利用DNA肿瘤病毒和电离辐射的协同作用。 永生化人表皮角质形成细胞的体外转化 似乎涉及多个事件。 第一个是 由于感染，获得无限增长潜力 AD 12-SV 40杂合病毒。 第二个问题是， 细胞生长特性作为连续暴露于电离 辐射 这种辐射诱导的转化导致了形态学上的 改变，在软琼脂中生长和形成能力差 分化的鳞状细胞癌的无胸腺裸鼠。 随后，我们已经能够证明存在的主导 在这种辐射诱导的恶性表型中转化人类序列 使用NIH/3 T3致瘤性测定。 这些观察结果表明，使用永生化/启动的人 表皮角质形成细胞提供了一个模型，在其中研究的分子 辐射致癌作用的后期阶段所涉及的事件。 目标 这项提议的一个重要目的是克隆和鉴定已经被 在辐射诱导的发展过程中激活或失活 恶性表型 一旦被隔离并确认身份，我们建议 实验研究了它们在辐射诱导过程中的作用 转型 这些实验的结果将提供一种见解 辐射致癌的分子基础，并可能提供一个 评估人类受试者风险的遗传基础。

Ionizing radiation is a carcinogen that induces malignancies in human and animal model systems. It is known to have the potential to participate at many points in the multistep process of cancer development. This multistep process reflects the cellular evolution from normal through initiated, preneoplastic and premalignant to neoplastic and malignant cells. We have recently demonstrated the induction of a malignant phenotype in human cells using the concerted action of a DNA tumor virus and ionizing radiation. This transformation of immortalized human epidermal keratinocytes in vitro by ionizing radiation appeared to involve multiple events. The first was the acquisition of unlimited growth potential as a result of infection with the AD12-SV40 hybrid virus. The second involved further changes in cellular growth properties as a result of successive exposures to ionizing radiation. This radiation-induced transformation resulted in morphological alterations, growth in soft agar and the ability to form poorly differentiated squamous cell carcinomas in athymic nude mice. Subsequently, we have been able to demonstrate the presence of dominant transforming human sequences in this radiation-induced malignant phenotype using the NIH/3T3 tumorigenicity assay. These observations indicate that the use of immortalized/initiated human epidermal keratinocytes provides a model in which to study the molecular events involved in the later phases of radiation carcinogenesis. The goal of this proposal is to clone and identify the cellular genes that have been activated or inactivated during the development of this radiation-induced malignant phenotype. Once isolated and identified, we propose to verify experimentally their roles in the process of radiation-induced transformation. The results of these experiments will offer an insight into the molecular basis for radiation carcinogenesis and may provide a genetic basis for the assessment of human subjects at risk.