Regulation of Death Ligand-Induced Killing

 描述(申请人提供)：由于细胞凋亡是一种生化上不同的细胞死亡形式，是化疗或免疫疗法在癌细胞中引发的主要反应之一，因此人们对了解细胞凋亡过程的调控一直很感兴趣。过去二十年的研究表明，死亡受体，肿瘤坏死因子受体超家族的一个亚家族，在反应中起着关键作用。 对某些癌症化疗药物，对死亡配体，如肿瘤坏死因子相关的凋亡诱导配体(TRAIL)和Fas配体，以及对表达这些配体的细胞毒淋巴细胞。因此，更好地了解决定死亡受体结扎是否会导致细胞死亡的因素，对癌症化疗和免疫治疗的某些方面具有潜在的影响。我们的初步研究为死亡受体调控的多个不同方面提供了新的见解。从细胞表面死亡受体的测量向后工作，我们发现死亡配体信号转导的结果受到影响死亡受体到细胞表面的运输、DEH受体mRNA的稳定性和死亡受体基因转录激活的因素的影响。为了建立在这些观察的基础上，我们现在建议1)阐明蛋白激酶C抑制死亡受体向细胞表面转运的途径，2)研究RNA结合蛋白如何调节死亡受体mRNA的半衰期，以产生表现出Bcl2非依赖性和Bcl2可抑制死亡配体诱导的信号的细胞，以及3)确定PARP抑制剂通过转录因子Sp1作用于AML细胞和临床AML样本体外增强死亡配体诱导的细胞凋亡的机制。如果成功，这些拟议的实验不仅将为死亡受体介导的细胞凋亡的调控提供新的见解，而且还将产生临床前数据，进一步支持测试新的死亡配体/化疗组合。

 DESCRIPTION (provided by applicant): Because apoptosis, a biochemically distinct form of cell death, is one of the major responses triggered in cancer cells by either chemotherapy or immunotherapy, there has been substantial interest in understanding regulation of the apoptotic process. Studies performed over the past two decades have demonstrated that death receptors, a subfamily of the tumor necrosis factora receptor superfamily, play critical roles in the response to certain cancer chemotherapeutic agents, to death ligands such TNF-related apoptosis-inducing ligand (TRAIL) and Fas ligand, and to cytotoxic lymphocytes that express these ligands. Thus, improved understanding of factors that determine whether death receptor ligation will induce cell death or not has potential implications for certain aspects of both cancer chemotherapy and immunotherapy. Our preliminary studies have provided new insight into multiple different aspects of death receptor regulation. Working backwards from measurement of cell surface death receptors, we have shown that the outcome of death ligand signaling is impacted by factors that affect trafficking of death receptors to the cell surface, stability of deth receptor mRNA, and transcriptional activation of death receptor genes. To build on these observations, we now propose to 1) elucidate the pathway by which protein kinase C inhibits trafficking of death receptors to the cell surface, 2) investigate how death receptor mRNA half-life is regulated by RNA binding proteins to produce cells that exhibit Bcl-2 independent vs. Bcl-2 inhibitable death ligand- induced signaling, and 3) determine the mechanism by which PARP inhibitors, acting through the transcription factor Sp1, enhance death ligand-induced apoptosis in AML cells and clinical AML samples ex vivo. If successful, the proposed experiments will not only provide new insight into the regulation of death receptor-mediated apoptosis, but also generate preclinical data in further support of testing a novel death ligand/chemotherapy combination.