PROJECT SUMMARY Tyrosine kinase inhibitors (TKIs) have been shown to significantly decrease a variety of malignancy-related mortality in the past two decades. However, concerns have been raised due to their potential vascular toxicity that could lead to hypertension, myocardial infarction, stroke, and peripheral arterial diseases. Despite these safety concerns, the mechanisms underlying TKI-induced vascular toxicity (TKI-VT) are poorly understood. To overcome this challenge, we propose to leverage human iPSCs, state-of-the-art multi-omics methods, and CRISPR screening to investigate molecular and cellular mechanisms of TKI-VT and identify druggable targets that can be further tested in animal models. Specifically, in Aim 1, we will comprehensively profile human-induced pluripotent stem cell-derived cardiac pericytes (iPSC-PCs), an important but rarely explored cardiac cell type, to define cellular mechanisms of TKI-VT. In Aim 2, we will evaluate how TKIs induce disrupted cellular crosstalk between iPSC-PCs and iPSC-derived endothelial cells (iPSC-ECs) by performing integrative omics on a 3D vessel-on-chip (VoC) model. Finally, in Aim 3, we will perform CRISPR screening on TKI-treated iPSC-PCs and iPSC-ECs to identify potential druggable targets and validate their therapeutic efficacy in mice. Successful completion of these studies will lead to novel mechanistic insights into TKI-VT pathogenesis and help develop promising therapeutic strategies that can prevent and/or treat TKI-VT in cancer patients. Moreover, this proposal will help define the role of TKIs in vascular pathophysiology, which may have broad scientific and clinical implications beyond cardio-oncology.