Growth inhibitory effects of dihydroartemisinin on pancreatic cancer cells: involvement of cell cycle arrest and inactivation of nuclear factor-kappaB.

PURPOSE: In a recent publication, we have shown that dihydroartemisinin (DHA), a derivative of antimalaria drug artemisinin, inhibits growth of pancreatic cancer cells in vitro and in vivo mediated by its anti-proliferative and pro-apoptotic effects. As it has been shown that the apoptosis might be induced due to cell cycle arrest, and that transcriptional factor nuclear factor-kappa B (NF-kappaB) plays vital roles in the apoptosis of pancreatic cancer cells, we extend our study to investigate the effects of DHA on cell cycle progression and NF-kappaB activity in pancreatic cancer cells to further reveal the anticancer effects of DHA on pancreatic cancer.
METHODS: Cell cycle progression was determined by propidium iodide staining and flow cytometry. Changes in the expression of cell cycle-associated proteins were detected using Western blot analysis. Measurement of NF-kappaB activity was performed with immunoblot analyzing the nuclear protein expression of NF-kappaB/p65 and ELISA detecting the NF-kappaB DNA-binding activity.
RESULTS: The treatment with DHA resulted in a dose-dependent G(0)/G(1) cell cycle arrest and regulated the expression of some cyclins, cdks and cdk inhibitors that involved in the G(0)/G(1) cell cycle progression such as cyclin E, cdk2, cdk4 and p27(Kip1) in pancreatic cancer BxPC-3 and AsPC-1 cells. The translocation and DNA-binding activity of NF-kappaB were inhibited in DHA-treated cells in a dose-dependent manner, indicated the inactivation effects of DHA in pancreatic cancer cells.
CONCLUSIONS: Together with our previous observations, our data show that DHA induces cell cycle arrest and apoptosis in pancreatic cancer cells, and this effect might be due to inhibition of NF-kappaB signaling. We suggest that DHA could be developed as a novel agent against pancreatic cancer.