PROJECT SUMMARY/ABSTRACT Background: Mutations in receptor tyrosine kinase (RTK) signaling genes such as Fms-Like Tyrosine Kinase 3 (FLT3) and the KIT proto-oncogene occur in two-thirds of acute myeloid leukemia (AML) and are associated with high relapse rates. FLT3 tyrosine kinase inhibitors (TKIs) are clinically active in FLT3-mutant AML but duration of response is limited by the development of resistance due to re-activation of RAS signaling. No specific proven therapy exists for these relapsed patients or patients with other signaling mutations. Rationale: The protein tyrosine phosphatase SHP2 is a central node in RAS activation and propagation of growth factor signals. SHP2 modulates MAPK pathway activation downstream of RTKs but the full molecular mechanisms of SHP2 activity are not clear. Small molecule allosteric inhibitors of SHP2 such as RMC-4630 stabilize the closed, autoinhibited conformation of SHP2 and are in clinical development. The goal of this application is to leverage new allosteric SHP2 inhibitors (SHP2i) to elucidate the molecular role of SHP2 in RTK-mediated survival in AML and test the efficacy of SHP2i in combination with the BCL2 inhibitor (BCL2i) venetoclax. Methods: We will test the therapeutic efficacy of SHP2i in combination with BCL2i in FLT3 and KIT mutant AML. We will use single cell multiomic sequencing to discover biomarkers of response and resistance. Using biochemical and proteomic approaches, we will assess the effect of SHP2i on RTK signaling in FLT3 and KIT mutant AML cells and associated effects on apoptosis. We will isolate the role of RAS/MAPK transcriptional activation in SHP2-mediated survival and determine the role of SHP2 in adhesion-mediated survival signaling in RTK-driven AML. Expected Results: We anticipate that these studies will uncover new knowledge about the role of SHP2 in leukemic cell survival and facilitate rational development of SHP2i combination therapies, particularly in combination with BCL2i. The overall goal of this work is to develop SHP2 inhibitor therapy as a novel treatment strategy in RTK-driven AML.