ONCOGENE EXPRESSION AND RADIORESISTANCE IN TUMOR CELLS

肿瘤细胞中的癌基因表达和放射抗性

• 批准号: 3203071
• 负责人: JERRY R WILLIAMS
• 金额: $ 24.62万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-30 至 1995-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3203071
• 关键词: all trans retinol; cell cycle; colorectal neoplasms; gene expression; genetic library; lung neoplasms; molecular cloning; molecular oncology; neoplastic cell; neoplastic process; oncogenes; radiation genetics; radiation resistance; receptor; retinoate; subtraction hybridization; transfection

Radioresistance correlates with expression of particular oncogenes in some cell systems, but not others. Further, since not all "radioresistant" cells express the same combination of oncogenes, the effects of oncogene expression may be modulated by cell-dependent factors. If there is a common radioresistant cell state, it is "downstream" from the initial expression of the oncogene(s). We propose to exploit two aspects of our recent work to attack this problem: 1) more detailed characterization of molecular events associated with human lung tumor progression; 2) more detailed characterization of radioresistance of human tumor cells. One of us has developed and characterized a series of human lung cancer cell lines, demonstrating the specific oncogene expression needed for transition from the more therapy-sensitive small cell lung cancer (SCLC) to the more therapy-resistant non-small cell lung cancer (NSCLC) phenotype. This transition has been characterized not only for changes in morphological phenotype, but also changes in relevant biochemical markers: TGF-alpha, EGF-R, PDGF and retinoic acid receptor gamma (RAR-gamma). Our major findings conclude that transition to the resistant phenotype can be effected by elevated expression of the mutated ras oncogene, complemented by elevated expression of c-myc or N-myc, not L-myc. Importantly, insertion of the RAR-gamma gene can also effect transition to the more resistant phenotype. Further, we have shown that SCLC cells transfected with the RAR-gamma gene express the sensitive or resistant phenotype depending upon extracellular levels of trans-retinoic acid (TRA). We will characterize radioresistance, both to acute and protracted radiation in these human lung cancer cell lines, and correlate radioresistance to oncogene expression as modulated by RAR-gamma. We have demonstrated that radioresistance to acutely delivered radiation is associated, in human tumor cells in general, with increased susceptibility to delay in G2-M phases of the cell cycle, where cells are rendered more sensitive to radiation. The proposed studies should determine whether any of the parameters characterizing radioresistance, including G2 delay, correlate with the molecular events associated with the change in phenotype from SCLC to NSCLC. If TRA inhibits transition to increased radioresistance, we will isolate genes that alter expression during such transition. Finally, we will transfect radiosensitive cells derived from human colorectal cancers with myc-ras and RAR-gamma vectors to determine whether these genes will increase radioresistance in other human cancer types. These studies should not only produce new insights into the relationship between expression of certain genes and radioresistance but may also suggest improved therapy regimens combining acute and protracted radiation, perhaps with TRA.

放射线与某些特定癌基因的表达相关 细胞系统，但没有其他。 此外，由于并非所有“放射线抗性” 细胞表达相同的癌基因组合，癌基因的作用 表达可以由细胞依赖性因子调节。 如果有一个 常见的辐射耐药细胞状态，从初始开始是“下游” 癌基因的表达。 我们建议利用我们的两个方面 攻击此问题的最新工作：1）更详细的表征 与人肺肿瘤进展相关的分子事件； 2）更多 人类肿瘤细胞辐射的详细表征。 之一 美国已经开发并表征了一系列人类肺癌细胞 线，证明过渡所需的特定癌基因表达 从对治疗更敏感的小细胞肺癌（SCLC）到更多 耐药的非小细胞肺癌（NSCLC）表型。 这 过渡不仅是形态变化的特征 表型，但也会变化相关的生化标记：TGF-Alpha， EGF-R，PDGF和视黄酸受体伽马（RAR-GAMMA）。 我们的专业 调查结果得出结论，向抗性表型的过渡可以是 由突变的RAS癌基因表达升高，互补 通过C-MYC或N-MYC的表达升高，而不是L-MYC。 重要的是， 插入RAR-GAMMA基因也会影响到更多 抗性表型。 此外，我们已经表明SCLC细胞转染 用RAR-GAMMA基因表达敏感或抗性表型 取决于细胞外摩酸（TRA）的水平。 我们将表征放射线，无论是急性还是持久 这些人肺癌细胞系中的辐射，并相关 由RAR-GAMMA调节的对癌基因表达的辐射势。 我们有 证明对急性递送辐射的放射性是 通常，在人类肿瘤细胞中，敏感性增加 延迟细胞周期的G2-M阶段，其中细胞的渲染更多 对辐射敏感。 拟议的研究应确定是否有 表征辐射势的参数，包括G2延迟， 与与表型变化相关的分子事件相关 从SCLC到NSCLC。 如果TRA抑制过渡到增加 放射线，我们将分离出在这种情况下改变表达的基因 过渡。 最后，我们将转染从源自 与MYC-RAS和RAR-GAMMA媒介的人类结直肠癌以确定 这些基因是否会增加其他人类癌症的辐射率 类型。 这些研究不仅应该对 某些基因的表达与放射性的关系，但 还可能表明改进的治疗方案结合了急性和持久的治疗方案 辐射，也许有Tra。