Identifying Mitophagy Receptors as Targets in Ras-dysregulated Cells

胰腺导管腺癌(PDAC)的五年存活率约为5%，使其成为 美国最致命的癌症之一。尽管90%以上的PDAC包含 激活编码GTPase KRAS基因的突变，发展小分子 KRAS的抑制剂只对G12C等位基因有效，占KRAS突变的3% PDAC。因此，对KRAS驱动的转化和肿瘤发生至关重要的抑制通路 可能为PDAC靶向治疗的发展提供一条更有前途的途径。一条这样的路径 这是为了响应致癌的KRAS表达而上调的，它包括一系列分解代谢过程 称为自噬。事实上，大量指示性出版物表明，自噬可能代表着一种 某些侵袭性和难治性癌症的阿喀琉斯之踵，以及全球范围内阻止自噬的抑制剂 在PDAC的细胞培养和小鼠模型中显示出了一些前景。然而，治疗浓度 这些自噬抑制剂中的一种会导致毒性。进一步的翻译进展受到了 缺乏特定试剂：自噬实际上不是一个单一的过程，而是一个广泛的途径家族 具有明显的货物偏好和招募机制。最近，致癌的KRasG12V表达， 占PDAC中KRAS突变的30%，已被证明导致a基因上调 一种特殊形式的自噬，称为有丝分裂吞噬，其中特定的有丝分裂受体标记线粒体 为了降级。这项提议的目的是确定有丝分裂在KRasG12V转化中的作用 和PDAC。我们的中心假设是KRAS失调导致吞噬丝裂原上调 促进肿瘤性转化。为了检验这一假设，我们制定了两个具体目标。目标1将 确定KRasG12V转化所需的已知有丝分裂受体。此外，在 对于哺乳动物细胞，这些途径中的许多都是多余的，防止了转化细胞的容易分离。 Aim 2将利用结构和遗传方法的新组合来识别新的有丝分裂吞噬 受体和同源相互作用伙伴，从而探索RAS失调中有丝分裂的吞噬机制

The five year survival rate for pancreatic ductal adenocarcinomas (PDAC) is approximately 5% making it one of the most lethal cancers in the United States. Despite the fact that more than 90% of PDAC contain activating mutations within the gene encoding the GTPase KRas, the development of small-molecule inhibitors for KRas has only been successful for the G12C allele accounting for 3% of KRAS mutations in PDAC. As such, inhibiting pathways which are essential for KRas-driven transformation and tumorigenesis may provide a more promising avenue for the development of PDAC targeted therapies. One such pathway that is upregulated in response to oncogenic KRas expression encompasses a set of catabolic processes termed autophagy. Indeed, a wealth of indicative publications suggest that autophagy could represent an Achilles’ heel for certain aggressive and intractable cancers, and inhibitors that globally block autophagy have shown some promise in cell culture and mouse models of PDAC. However, therapeutic concentrations of these autophagy inhibitors resulted in toxicity. Further translational progress has been hampered by the lack of specific reagents: autophagy is actually not a single process but rather a broad family of pathways with distinct cargo preferences and mechanisms of recruitment. Recently, oncogenic KRasG12V expression, which accounts for 30% of KRAS mutations in PDAC, has been shown to result in the upregulation of a specialized form of autophagy, termed mitophagy, in which specific mitophagy receptors mark mitochondria for degradation. The goal of this proposal is to determine the role of mitophagy in KRasG12V transformation and PDAC. Our central hypothesis is that KRas dysregulation leads to the upregulation of mitophagy to promote neoplastic transformation. To test this hypothesis we have developed two specific aims. Aim 1 will determine which of the known mitophagy receptors are required for KRasG12V transformation. Furthermore, in mammalian cells, many of these pathways are redundant, preventing facile dissection in transformed cells. Aim 2 will leverage a novel combination of structural and genetic approaches to identify novel mitophagy receptors and cognate interaction partners and thus explore mechanisms of mitophagy in Ras-dysregulated