Effect of PUMA gene transfection in breast cancer cells (MCF-7) on enhancing the sensitivity of epirubicin-induced apoptosis

Abstract

Objective: To investigate if PUMA gene transfection could increase the sensitivity of breast cancer cells (MCF-7) on Epirubicin-induced apoptosis. Methods: PUMA-pCDNA3, which contains full length PUMA cDNA or -pCDNA3, was transfected into the human breast cancer cell line MCF-7 by using lipofectamine. G418 selection was used to select positive cells. MCF-7, MCF-7/PUMA, and MCF-7/pCDNA3 cells were respectively treated with serial concentrations of Epirubicin (0.01 μmol/L to 100 μmol/L). MTT assay was performed to determine the cell survival rate in each group. IC50 of Epirubicin was then calculated. TUNEL and FCM were employed to investigate cell apoptosis. Western blot was performed to detect PUMA protein expression. Results: The Epirubicin IC50 values of MCF-7, MCF-7/PUMA, and MCF-7/pCDNA3 cells were (13±1.4), (1.8±0.2), and (10.7±1.3) μmol/L, respectively. The sensitivity of MCF-7/PUMA cells had a 7.2-fold increase. The Epirubicin-induced apoptosis of MCF-7 cells behaved in a dose-dependent manner. The apoptosis of MCF-7/ PUMA cells was more prominent than that of MCF-7 and MCF-7/ pCDNA3 cells. At a low concentration (0.1 μmol/L), Epirubicin could only slightly induce MCF-7/ pCDNA3 cells [(1.15±0.26)%] and MCF-7 cells [(0. 9±0.24)%], as well as the apoptosis in MCF-7/PUMA cells [(6.44±1.46)%]. At a high concentration, Epirubicin (1.0 μmol/L) could induce apoptosis in all groups. The apoptotic rate was significantly higher in MCF-7/PUMA cells [(35.47±9.36)%] than in MCF-7/ pCDNA3 cells [(15.2±5.17)%] and in MCF-7 cells [(12.6±3.73)%], both P<0. 01). Results obtained from FCM and TUNEL were the same. PUMA protein expression was significantly higher in MCF-7/PUMA cells than in MCF-7 and MCF-7/pCDNA3 cells. Conclusion: PUMA gene transfection greatly enhances the sensitivity of MCF-7 cells during Epirubicin-induced apoptosis.