Dihydrosanguinarine suppresses pancreatic cancer cells via regulation of mut-p53/WT-p53 and the Ras/Raf/Mek/Erk pathway.

Background: There have been some reports implicating the pharmacologic action of Dihydrosanguinarine (DHSA), but little research including the effects of it on cancer cells. PANC-1 cells have mutations in K-Ras and TP53, which respectively express mutant K-Ras and p53 protein, and the mutations in Ras/p53 have been believed with closely relationship to the occurrence of various tumors.

Purpose: To reveal the inhibition of Dihydrosanguinarine on pancreatic cancer cells (PANC-1 and SW1990) proliferation by inducing G0/G1 and G2/M phase arrest via the downregulation of mut-p53 protein, inducing apoptosis and inhibiting invasiveness through the Ras/Mek/Erk signaling pathway.

Methods: Human pancreatic cancer cell lines were cultured with cisplatin and DHSA. Then, cell proliferation, the cell cycle and apoptosis were measured by CCK-8 and flow cytometry. The migratory and invasive abilities of pancreatic cancer cells were evaluated by transwell assay. The expression levels of mRNA and protein were measured by RT-PCR and western blotting.

Results: The results showed that DHSA treatment inhibited cell proliferation, migration and invasion in a time- and dose-dependent manner and led to induction of cell cycle arrest and apoptosis. G0/G1 and G2/M phase arrest inhibited the viability of PANC-1 cells by downregulating the expression of mut-p53 protein. Decreased levels of C-Raf and Erk phosphorylation in DHSA-treated PANC-1 and SW1990 cells were observed in a time- and dose-dependent manner. However, the total expression of p53 and Ras proteins had a different change in PANC-1 and SW1990 cells.

Conclusions: Our findings offer the novel perspective that DHSA inhibits pancreatic cancer cells through a bidirectional regulation between mut-p53/-Ras and WT-p53/-Ras to restore the dynamic balance by Ras and p53 proteins.