RK-24466, a lymphocyte-specific protein tyrosine kinase (Lck) inhibitor, significantly inhibited both VSMC proliferation and migration. RK-24466 suppresses VSMC proliferation and migration via down-regulating the protein kinase B (Akt) and extracellular signal regulated kinase (ERK) pathways, and it significantly decreased the expression of proliferating cell nuclear antigen (PCNA) and cyclin D1 and, the phosphorylation of retinoblastoma protein (pRb). Additionally, RK-24466 suppressed the migration of VSMCs from endothelium-removed aortic rings, as well as neointima formation following rat carotid balloon injury. The present study identified RK-24466 as a potent VSMC proliferation and migration inhibitor and warrants further studies to elucidate its more detailed molecular mechanisms, such as its primary target, and to further validate its in vivo efficacy as a therapeutic agent for pathologic vascular conditions, such as restenosis and atherosclerosis[1].