PAI-1 and Platelets drive a Metastatic Phenotype in Ovarian Cancer Cells RT-qPCR revealed an average 78.4% loss of PAI-1 mRNA transcripts in SK-OV-3 cells treated with siRNA versus negative control (siNEG) (Figure 1A; n = 3, p ≤ 0.0001). The gene discussed is SERPINE1; the disease is ovarian cancer.