DRUG RESISTANCE DUE TO LOSS OF BETA2 MICROGLOBULIN

由于β2微球蛋白缺失而产生耐药性

• 批准号: 6642972
• 负责人: Ahmad R. Safa
• 金额: $ 7.49万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-03 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6642972
• 关键词: antisense nucleic acid; apoptosis; cell cycle proteins; cell line; cell proliferation; complementary RNA; cytotoxicity; doxorubicin; drug interactions; drug resistance; gene expression; genetic regulation; genetic regulatory element; genetic transcription; interferon gamma; major histocompatibility complex; monoclonal antibody; neoplasm /cancer chemotherapy; neoplasm /cancer genetics; neoplasm /cancer pharmacology; pharmacokinetics; protein structure function; transcription factor; tumor necrosis factor alpha; vincristine

A major problem in cancer chemotherapy is intrinsic or acquired drug resistance. We recently found, for the first time, that the loss or decreased expression of beta2- miocroglobulin (beta2M) is involved in the development of drug resistance. This is a completely novel drug resistance mechanism which has not been previously described in the literature. Therefore, the overall goals of this project are (1) to unravel the molecular and biochemical mechanisms by which beta2M causes drug resistance, and (2) to develop strategies to circumvent drug resistance due to the loss of decreased expression of beta2m. The Specific Aims are to (1) determine whether cellular levels of beta2m influence the cell cycle; (2) determine whether beta2m plays a role in apoptosis in drug sensitive cells, and whether its loss or decreased expression prevents apoptotic cell death; (3) modulate the expression of beta2m by cytokines and thereby circumvent drug resistance; and (4) investigate the regulation of beta2m expression in drug resistant cells, and determine the molecular mechanisms of beta2m gene suppression in these cells. In order to accomplish Specific Aim 1, experiments will be conducted to and decreases or increases cell proliferation, respectively, and (2) whether beta2m modulates the function of specific cell of specific cell-cycle, and decreases or increases cell proliferation, respectively, and (b) whether beta2m modulates the function of specific cell cycle-controlling proteins. To pursue Specific Aim 2, the role of beta2m in apoptosis will be explored by (a) evaluating levels in cells transfected with the beta2m gene in the sense or antisense orientation, and (b) examine whether anti-beta2m monoclonal antibodies in the absence or presence of chemotherapeutic agents, induce apoptosis in drug sensitive, but not in beta2m-deficient, cells. In order to accomplish Specific Aim 3, experiments will be conduced to evaluate the modulating effects of interferon-gamma (IFN- gamma) and tumor necrosis factor alpha (TNF-alpha), with or without doxorubican or vincristine, on beta2m expression in cells with reduced beta2m expression and in beta2m transfectants. In Specific Aim 4, we will determine whether (a) IFN-gamma or TNF-alpha induces specific transcription factors to enhance transcription of the beta2m gene in drug resistant cells, and (b) determine whether reduced expression of beta2m in resistant cells is due to decreased or absent positive regulatory transcription factors, or the presence of transcription suppressors. These studies will aid in understanding the molecular mechanism(s) of this novel drug resistance phenotype due to the loss or decreased expression of beta2m, and will be useful for the development of more effective chemotherapeutic or potential gene therapy strategies.

癌症化疗的一个主要问题是内在的或获得性的耐药性。我们最近首次发现，β2-微球蛋白（β2M）表达的缺失或减少与耐药性的发展有关。这是一种全新的耐药机制，以前的文献中从未描述过。因此，该项目的总体目标是（1）揭示β2M引起耐药性的分子和生化机制，以及（2）制定策略来规避由于β2m表达减少而导致的耐药性。具体目标是 (1) 确定 β2m 的细胞水平是否影响细胞周期； (2)确定β2m是否在药物敏感细胞的凋亡中发挥作用，以及其缺失或表达减少是否可以阻止凋亡细胞死亡； (3)通过细胞因子调节β2m的表达，从而规避耐药性； (4)研究耐药细胞中β2m表达的调控，并确定这些细胞中β2m基因抑制的分子机制。为了实现特定目标1，将分别进行实验以降低或增加细胞增殖，以及（2）β2m是否调节特定细胞周期的特定细胞的功能，以及分别降低或增加细胞增殖，以及（b）β2m是否调节特定细胞周期控制蛋白的功能。为了实现具体目标 2，将通过以下方式探索 β2m 在细胞凋亡中的作用：(a) 评估以有义或反义方向转染 β2m 基因的细胞中的水平，以及 (b) 检查抗 β2m 单克隆抗体在化疗药物不存在或存在的情况下是否会诱导药物敏感细胞的细胞凋亡，但不会诱导β2m 缺陷细胞的细胞凋亡。为了实现具体目标 3，将进行实验以评估干扰素-γ (IFN-γ) 和肿瘤坏死因子 α (TNF-α) 在有或没有阿霉素或长春新碱的情况下对 β2m 表达减少的细胞和 β2m 转染子中的 β2m 表达的调节作用。在具体目标 4 中，我们将确定 (a) IFN-γ 或 TNF-α 是否诱导特定转录因子以增强耐药细胞中 β2m 基因的转录，以及 (b) 确定耐药细胞中 β2m 表达减少是否是由于正调节转录因子减少或缺失，或者转录抑制因子的存在。这些研究将有助于理解由于 β2m 表达缺失或减少而导致的这种新型耐药表型的分子机制，并将有助于开发更有效的化疗或潜在的基因治疗策略。