Curcumin enhanced antiproliferative effect of mitomycin C in human breast cancer MCF-7 cells in vitro and in vivo

Abstract

Aim:To investigate the efficacy of mitomycin C (MMC) in combination with curcumin in suppressing human breast cancer in vitro and in vivo.Methods:Human breast cancer MCF-7 cells were used. Cell viability was measured using MTT assay. The cell cycle phase was detected with flow cytometric analysis. Cell cycle-associated proteins were examined using Western blot analysis. MCF-7 breast cancer xenografts were established to monitor tumor growth and cell cycle-associated protein expression.Results:Curcumin inhibited MCF-7 breast cancer cell viability in a concentration-dependent manner (IC50 value=40 μmol/L). Similarly, MMC inhibited the cell viability with an IC 50 value of 5 μmol/L. Combined treatment of MMC and curcumin showed a synergistic antiproliferative effect. In the presence of curcumin (40 μmol/L), the IC50 value of MMC was reduced to 5 μmol/L. In MCF-7 xenografts, combined administration of curcumin (100 mg/kg) and MMC (1-2 mg/kg) for 4 weeks produced significantly greater inhibition on tumor growth than either treatment alone. The combined treatment resulted in significantly greater G 1 arrest than MMC or curcumin alone. Moreover, the cell cycle arrest was associated with inhibition of cyclin D1, cyclin E, cyclin A, cyclin-dependent kinase 2 (CDK2) and CDK4, along with the induction of the cell cycle inhibitor p21 and p27 both in MCF-7 cells and in MCF-7 xenografts. These proteins were regulated through p38 MAPK pathway.Conclusion:The results suggest that the combination of MMC and curcumin inhibits MCF-7 cell proliferation and cell cycle progression in vitro and in vivo via the p38 MAPK pathway. © 2011 CPS and SIMM All rights reserved.