PTCH1 and Patent ductus arteriosus: To determine whether lithium suppresses PDA cell proliferation through modulating the activity of Hh pathway, PANC-1 cells were treated with different concentrations of lithium chloride (10 mM, 20 mM, 40 mM) for 24 hours, and real-time PCR was carried out to monitor the expression levels of SHH, PTCH1, SMO, FU, SUFU, GLI1 and Hh pathway target gene HHIP and CCND1. As shown in Figure 4A, the mRNA levels of HHIP, CCND1 and PTCH1 were markedly decreased, suggesting that the activity of Hh pathway was downregulated.