Defining the role of proteostasis pathways in cancer drug resistance

定义蛋白质稳态途径在癌症耐药性中的作用

• 批准号: 8525960
• 负责人: Erica Lynn Cain
• 金额: $ 4.71万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8525960
• 关键词: Address; Alleles; Antineoplastic Agents; Biochemical Pathway; Bypass; Cell Death; Cells; Critical Pathways; DNA Repair; Dependence; Development; Drug Targeting; Drug resistance; Evolution; Genes; Genetic; Maintenance; Malignant Neoplasms; Molecular; Molecular Chaperones; Mutate; Mutation; Ovary; Pathway interactions; Pharmacotherapy; Poly(ADP-ribose) Polymerases; Population; Predisposition; Prostate; Proteins; Quality Control; RNA Interference; Research; Resistance; Role; Technology; Testing; Work; biological adaptation to stress; cancer cell; drug sensitivity; effective therapy; genome-wide; inhibitor/antagonist; insight; killings; loss of function; malignant breast neoplasm; mutant; pressure; prevent; protein expression; protein folding; public health relevance; response; screening; small hairpin RNA; treatment strategy; tumor

DESCRIPTION (provided by applicant): Acquired resistance to drugs targeting proteins essential for cancer survival is a major hurdle for the effective treatment of cancer. In most cases the molecular components that drive the evolution and maintenance of drug resistance are not well defined, but are likely to be conserved amongst cancer subtypes. Thus, the identification of cellular pathways important for cancer drug resistance is critical for the development of new treatment strategies. A clear example of the evolution of drug resistance in a cancer population is resistance to Poly ADP-Ribose Polymerase (PARP) inhibitors (PARPi) in BRCA2-deficient cancers. Both Breast Cancer 2 susceptibility protein (BRCA2) and PARP1 function in DNA repair. Loss-of-function of either gene is not lethal, however, loss of both leads to an accumulation of double-strand breaks and cell death. This synthetic lethal interaction has made PARPi an attractive drug therapy for BRCA2-deficient cancers of the breast, prostate, and ovary; however, PARPi resistance arises from the expression of BRCA2 reversion alleles encoding a mutated, but functional, BRCA2 protein. The revertant BRCA2 protein is missing large parts of the wild-type protein and likely has increased instability and dependence on molecular chaperones. Additionally, the expression of mutated versions of BRCA2 from multiple alleles in PARPi-resistant cells likely places a significant burden on the proteostatic machinery that exists to sense and respond to changes in cellular protein folding requirements. It follows that to maintain the expression of this mutant protein and to alleviate challenges to the cells protein folding capacity, PARPi exerts a selective pressure resulting in dependence on altered proteostasis pathways for survival. I propose to test this hypothesis by addressing the following aims: 1) Characterize the dependence and effects of BRCA2 revertant protein expression on protein quality control and stress response pathways. 2) Determine whether PARPi-resistant cancer cells with BRCA2 reversion alleles rely on proteostasis pathways for survival. 3) Use an unbiased genome wide RNA interference screen to identify genes required for the survival and/or maintenance of drug resistance of PARPi-resistant cancer cells with BRCA2 reversion alleles. We expect that by the completion of these proposed studies, we will have identified the components of protein quality control and stress response pathways that are critical for the survival and/or maintenance of drug resistance in PARPi-resistant tumors that re-acquire functional BRCA2 proteins through reversion mutations. The components and pathways identified by this work will provide proof- of-concept mechanisms that may be exploited in developing new treatment strategies to prevent the escape of drug resistant populations of cancer cells. !

描述（由申请人提供）：对靶向癌症生存所必需的蛋白质的药物的获得性耐药性是有效治疗癌症的主要障碍。在大多数情况下，驱动耐药性演变和维持的分子组分并没有很好地定义，但可能在癌症亚型中是保守的。因此，识别对癌症耐药性重要的细胞途径对于开发新的治疗策略至关重要。癌症群体中耐药性演变的一个明显例子是BRCA 2缺陷型癌症对聚ADP-核糖聚合酶（PARP）抑制剂（PARPi）的耐药性。乳腺癌易感蛋白2（BRCA 2）和PARP 1都在DNA修复中起作用。任一基因的功能丧失都不是致命的，然而，两者的丧失都会导致双链断裂的积累和细胞死亡。这种合成的致命相互作用使PARPi成为乳腺癌、前列腺癌和卵巢癌BRCA 2缺陷的有吸引力的药物疗法;然而，PARPi耐药源于编码突变但功能性BRCA 2蛋白的BRCA 2回复等位基因的表达。回复突变BRCA 2蛋白缺失了野生型蛋白的大部分，并且可能增加了不稳定性和对分子伴侣的依赖性。此外，来自PARPi抗性细胞中的多个等位基因的BRCA 2的突变形式的表达可能对存在以感测和响应细胞蛋白质折叠要求的变化的蛋白质抑制机制造成显著负担。因此，为了维持这种突变蛋白的表达并减轻对细胞蛋白折叠能力的挑战，PARPi施加选择性压力，导致依赖于改变的蛋白质稳态途径生存。我建议通过解决以下目标来验证这一假设：1）表征BRCA 2回复突变蛋白表达对蛋白质质量控制和应激反应途径的依赖性和影响。2)确定具有BRCA 2逆转等位基因的PARPi耐药癌细胞是否依赖于蛋白质稳态途径存活。3)使用无偏倚的全基因组RNA干扰筛选来鉴定具有BRCA 2回复等位基因的PARPi耐药癌细胞的存活和/或维持耐药性所需的基因。我们预计，通过完成这些拟议的研究，我们将确定蛋白质质量控制和应激反应途径的组成部分，这些组成部分对于通过回复突变重新获得功能性BRCA 2蛋白的PARPi耐药肿瘤的生存和/或维持耐药性至关重要。这项工作确定的组分和途径将提供概念验证机制，可用于开发新的治疗策略，以防止耐药癌细胞群逃逸。!