RADIOBIOLOGICAL STUDIES OF HUMAN HYBRID CELL LINES

拟议研究的长期目标有几个。 第一 是为了更深入地了解 人体细胞的辐射敏感性以及遗传变化， 伴随的肿瘤转化可能影响放射敏感性。 的 第二，确定辐射引起的遗传变化， 人类细胞的肿瘤性转化。 三是获得 与辐射引起的各种问题有关的定量资料 人源细胞系的肿瘤转化。 医疗 建议的研究的意义主要是对领域的 放射致癌和放射治疗。 为达致这些长远目标，我们会继续进行研究， 充分表征的非致瘤性和致瘤性人细胞杂交体 细胞系（HeLa x皮肤成纤维细胞）。 此外，我们将启动新的 用人类微细胞杂交系（HeLa加上一个单拷贝的 人皮肤成纤维细胞染色体，最初是染色体11， 显示抑制HeLa细胞的致瘤性）。 建议资助期内的具体目标的理据如下 根据我们迄今为止的研究 这些目标包括（1）检查细胞 辐射敏感性和DNA损伤诱导和修复的周期依赖性 非致瘤性和致瘤性杂交细胞，（2）检查 PLDR和SLDR对细胞存活和肿瘤形成的贡献 用分级分离的和 低剂量率辐射和（3）分离和表征各种 辐射诱导的肿瘤细胞（包括探测损失） 肿瘤抑制基因）。 标准方法以及 无论是在私人研究所的实验室里开发的还是正在开发的。和 Co-P.I.将用于 将通过集落形成评估细胞存活 能力，碱和中性洗脱的DNA损伤;肿瘤性 肿瘤表达的免疫过氧化物酶测定转化 相关抗原，通过RFLP分析抑制基因的丢失，以及通过 当注射到裸鼠体内时，细胞生长肿瘤的能力。

The long term objectives of the proposed research are several. The first is to gain further understanding of the genetic control of the radiosensitivity of human cells and how the genetic changes which accompany neoplastic transformation may effect radiosensitivity. The second is to determine radiation-induced genetic changes associated with the neoplastic transformation of human cells. The third is to obtain quantitative information relating to various aspects of radiation-induced neoplastic transformation of human derived cell lines. The medical significance of the proposed research is principally to the fields of radiation carcinogenesis and radiation therapy. To approach these long term objectives, we will continue our studies with well characterized non-tumorigenic and tumorigenic human cell hybrid lines (HeLa x skin fibroblast). Furthermore, we will initiate new studies with human microcell hybrid lines (HeLa plus a single copy of a human skin fibroblast chromosome, initially chromosome 11 which has been shown to suppress the tumorigenicity of HeLa cells). The rationale for the Specific Aims for the proposed funding period is based on our studies to date. These aims include (1) examining the cell cycle dependency of radiosensitivity and DNA damage induction and repair of both non-tumorigenic and tumorigenic hybrid cells, (2) examining contribution of PLDR and SLDR to cell survival and neoplastic transformation for non-tumorigenic cells treated with fractionated and low dose-rate radiation and (3) isolating and characterizing various properties radiation-induced neoplastic cells (including probing for loss of tumor-suppressor gene). Standard methodologies as well as those either developed or being developed in the laboratories of the P.I. and Co-P.I. will be used. Cell survival will be assessed by colony forming ability, DNA damage by alkali and neutral elution; neoplastic transformation by immunoperoxidase assay of expression of tumor associated antigen, by loss of suppressor gene by RFLP analysis, and by ability of cells to grow tumors when injected into nude mice.