– WQ-C-401 is an orally active inhibitor of the platelet-derived growth factor receptor (PDGFR). It inhibits cell proliferation by blocking PDGFR auto-phosphorylation in a concentration-dependent manner, with EC50 values of 3.5 nM for PDGFRαY849 and 5.8 nM for PDGFRβY1021. Additionally, WQ-C-401 suppresses the proliferation and migration of PASMCs by inhibiting PDGF-BB-induced phosphorylation of ERK1/2, reduces collagen I synthesis, and increases α-SMA expression, thereby preventing pulmonary vascular remodeling. This compound shows promise for research in the field of pulmonary arterial hypertension.