SERPINE1 and ocular melanoma: To validate the activation of TGF-β1-mediated signaling induced by OM in VSMCs, we evaluated the transcription expression of PAI-1—the downstream gene of TGF-β1 (Fig. 5a)—and the phosphorylation of Smad2/3 (Fig. 5b–d) through quantitative real-time polymerase chain reaction (PCR) and immunoblotting, respectively.