Project 3: The AMPK Autophagy Pathway as a Metabolic Liability in Pancratic Ductal Adenocarcinoma

PROJECT SUMMARY – Project 3: Autophagy Pancreatic ductal adenocarcinoma (PDA) is one of the deadliest forms of cancer with few effective therapies. The poor performance of current treatments is partly due to metabolic adaptations in both the tumor and stromal compartments, such as the recycling of proteins and organelles through increased autophagy. As a hallmark of PDA, autophagy provides a key source of nutrients in the restrictive tumor microenvironment (TME). Accumulating evidence also implicates the autophagy program as a critical mediator of resistance to numerous therapeutics, including chemotherapy, MEK inhibitors, and immune checkpoint inhibition. Foundational research from the Shaw group decoded key biochemical steps involved in the initiation of autophagy, including upstream regulation of AMPK and its downstream activation of ULK1 and ULK2, the kinases that drive autophagosome formation. More recent work from the Shaw group has also revealed that AMPK can block the translocation of Class II HDACs to the nucleus. Despites these advances, the specific roles of AMPK in autophagy control and epigenetic regulation have never been investigated in pancreatic cancer. Moreover, while autophagy has emerged as an attractive therapeutic target in pancreatic cancer, efforts to translate this to the clinic have been hindered by a lack of autophagy-specific inhibitors, with only broad lysosomotropic agents like chloroquine available for study. To address this gap, the lab has developed novel, bioavailable inhibitors of ULK1 and ULK2, two of only three druggable enzymes specific to the autophagy pathway. These inhibitors provide critical tools with which to dissect the contributions of autophagy to PDA growth and form the basis for a new approach for overcoming therapeutic resistance in this deadly disease. Here, experiments proposed in Aim 1 will define when and where different facets of AMPK signaling and autophagy are activated during disease progression in the autochthonous mouse KPC model of PDA. In collaboration with Project 1, conditional deletions of AMPK or its downstream targets ULK1/2 and HDAC3 will be used to evaluate their contribution to metabolic adaptations driving tumor growth and epigenetic changes mediating tumor cellular functions. In addition, the contribution of AMPK pathway components in supporting PDA resistance to chemotherapeutics and targeted therapies will be dissected. In Aim 2, the roles of canonical and noncanonical autophagy in non-cell autonomous support of pancreatic tumor growth will be delineated by comparing stromal deletion of ULK1/2 and ATG7. In addition, experiments will dissect cell-specific requirements for autophagy within the fibroblast and myeloid compartments in supporting PDA therapeutic resistance. In Aim 3, the Shaw lab’s novel, bioavailable ULK inhibitor will be used to determine how selective inhibition of autophagy impacts PDA growth through reprogrammed tumor and stromal cell function. The potential of ULK inhibitors in rescuing autophagy-dependent therapeutic resistance to chemotherapies, MEK inhibitors, and immune checkpoint inhibition will be explored.