Using Synthetic Lethality to Select Cancer Drug Targets

描述（由申请人提供）：功能丧失肿瘤抑制基因（TSG）突变在癌症中很常见。两个基因是“合成致死”的，如果其中一个基因单独失活与生存能力兼容，但两个基因的失活导致死亡。理论上，对突变的TSG具有合成致死性的基因产物将是一个有吸引力的药物靶点，因为它的抑制作用应该杀死TSG（-/-）癌细胞，而不是正常的[TSG(+/+)]细胞。我们选择了在大多数透明细胞肾癌中发生突变的VHL肿瘤抑制基因来进一步探索这一范式。重要的是，VHL基因产物pVHL的失活不会严重影响体外细胞生长，否则可能会混淆我们的研究。此外，我们有多个匹配的（等基因）肾癌细胞系，这些细胞系含有或不含有野生型pVHL以及VHL（+/+）和VHL（-/-）秀丽隐杆线虫。缺乏pVHL的细胞过度产生一种称为HIF（缺氧诱导因子）的转录因子。因此，VHL (-/-) RCCs的转录组类似于缺氧细胞的转录组，后者在实体肿瘤中很常见，并且已知具有相对的耐药性。在具体目标1中，我们将使用化学生物学方法寻找选择性杀死VHL(-/-) rcc的化合物。这样的化合物可以作为探针来识别它们的蛋白质目标。在特定目标2中，我们将使用全基因组RNAi方法来鉴定选择性杀死VHL（-/-）秀丽隐杆线虫的基因。这些基因随后将被整合到人类rcc中，二级筛选将确定HIF的失调是否导致了VHL（-/-）和VHL（+/+）细胞在特定目的1和2中的敏感性差异。这些实验可能会发现新的药物靶点肾癌，特别是缺氧肿瘤细胞，一般。此外，它们可能为基于TSG失活突变选择抗癌药物靶点建立新的范例。

DESCRIPTION (provided by applicant): Loss of function tumor suppressor gene (TSG) mutations are common in cancer. Two genes are 'synthetically lethal' if inactivation of either gene alone is compatible with viability but inactivation of both genes leads to death. In theory, the product of a gene that was synthetically lethal to a mutated TSG would be an attractive drug target because its inhibition should kill TSG(-/-) cancer cells but not normal [TSG( +/+)] cells. We have chosen the VHL tumor suppressor gene, which is mutated in the majority of clear cell renal carcinomas, to explore this paradigm further. Importantly, inactivation of the VHL gene product, pVHL, does not grossly affect cell growth in vitro, which might otherwise confound our studies. Moreover, we have multiple matched (isogenic) renal carcinoma cell (RCC) lines that do or do not contain wild-type pVHL as well as VHL(+/+) and VHL (-/-) C. elegans. Cells lacking pVHL overproduce a transcription factor called HIF (hypoxia-inducible factor). Consequently, the transcriptomes of VHL (-/-) RCCs resemble that of hypoxic cells, which are common in solid tumors and known to be relatively chemoresistant. In specific aim 1 we will use chemical biological approaches to look for compounds that selectively kill VHL(-/-) RCCs. Such compounds might then be used as probes to identify their protein targets. In specific aim 2, we will use a genome-wide RNAi approach to identify genes that selectively kill VHL (-/-) C. elegans. These genes would then be interogated in human RCCs Secondary screens will address whether dysregulation of HIF is responsible for differential sensitivity of VHL (-/-) and VHL (+/+) cells in specific aims 1 and 2. These experiments may identify new drug targets for renal carcinoma, in particular, and hypoxia tumor cells, in general. Moreover, they may establish a new paradigm for the selection of anticancer drug targets based on inactivating mutations of TSG.