Simvastatin induces apoptosis of nasopharyngeal carcinoma cells through NF-κB signaling pathway.

Objective: The aim of this study was to investigate the mechanism of simvastatin-induced apoptosis in nasopharyngeal carcinoma (NPC) cells.
Materials and Methods: CNE1 and HK1 cell lines were treated with different concentrations of simvastatin for different time course. Subsequently, Cell Counting Kit-8 (CCK-8), colony formation assay, and flow cytometry were conducted to evaluate cell activity, colony formation ability, as well as cell cycle of NPC cells, respectively. The mRNA expressions of p21, Bim, and cyclin D1 were examined by qPCR. Meanwhile, the protein expression levels of apoptosis-related proteins (including caspase-3, Bax, Bcl-2) were detected by Western blot. Caspase-3 activity was determined to estimate cell apoptosis. An NPC xenotransplantation model was constructed to further determine the role of simvastatin in vivo. In addition, NF-κB activity was assessed through Luciferase reporter gene assay and Western blot.
Results: Simvastatin treatment lead to significantly reduced viability of NPC cells and the number of cell colonies dose-dependently and time-dependently. Meanwhile, simvastatin treatment caused cell cycle arrest in G0/G1 phase, remarkably downregulated expression of cyclin D1, and upregulated expressions of p21 and Bim. In addition, simvastatin induced apoptosis of NPC cells and enhanced the Luciferase activity of caspase-3. Western blot results indicated that simvastatin promoted the protein level of Bax and caspase-3, whereas suppressed the protein expression of Bcl-2. In vivo experiments showed that simvastatin was able to suppress the growth of NPC cells. Further studies demonstrated that simvastatin remarkably attenuated the Luciferase activity of pNF-κB-Luc, thereby specifically inhibiting the NF-κB signaling pathway.
Conclusions: Simvastatin inhibits proliferation and promotes apoptosis of NPC cells by inhibiting the NF-κB pathway.