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，有潜力参加 癌症发展的多步骤过程中的许多点。 这个多步骤 过程反映了细胞从正常到启动的进化， 肿瘤细胞和恶性细胞的肿瘤前期和恶变前期。 我们有 最近证明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 电离辐射似乎涉及多个事件。 第一个是 由于感染而获得无限的增长潜力 AD12-SV40 混合病毒。 第二个涉及进一步的改变 连续暴露于电离导致的细胞生长特性 辐射。 这种辐射诱导的转变导致了形态学 改变、软琼脂生长和形成能力差 无胸腺裸鼠的分化鳞状细胞癌。 随后，我们已经能够证明占主导地位的存在 在这种辐射诱导的恶性表型中改变人类序列 使用 NIH/3T3 致瘤性测定。 这些观察表明，使用永生化/起始的人类 表皮角质形成细胞提供了一个模型来研究分子 涉及辐射致癌作用后期的事件。 目标 该提案的目的是克隆和鉴定已被 在这种辐射诱导的发展过程中被激活或失活 恶性表型。 一旦隔离和识别，我们建议进行验证 实验表明它们在辐射诱导过程中的作用 转变。 这些实验的结果将提供一个见解 进入放射致癌的分子基础，并可能提供 评估处于危险中的人类受试者的遗传基础。

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.