In accordance with growth curve, colony formation assays showed that up-regulation of PVT1 triggered PDA cell growth, with attenuation of growth occurred when 3-MA was used, meanwhile, down-regulation of PVT1 suppressed PDA cell proliferation, with restoration of growth observed when rapamycin was used (Fig. 4b). This evidence concerns the gene PVT1 and Patent ductus arteriosus.