Study On The Role And Mechanism Of G1 Phase Arrest Of Amlodipine On Human Breast Carcinoma Cell Line MCF-7

Objective To observe the effects of calcium channel blocker (CCB)- amlodipine on the growing and cell cycle on human breast canner cell line MCF-7 and explore its potential mechanisms. To provide the theoretical basis of calcium channel blocker (CCB) on tumor chemotherapy for clinical applications.Methods Culture human breast carcinoma MCF-7 cells, the inhibitory effect of amlodipine on cell proliferation of human breast carcinoma MCF-7 was evaluated by MTT assay; cell cycle distribution was detected by flow cytometry(FCM); The expression of cell cycle-related protein such as cyclinD1, p21 and p53 were determined by immunocytochemistry; the mRNA expression levels of cell cycle-related genes cyclinD1 and p21 was treated by RT-PCR; while the protein expression of cyclinD1 and p21 was assessed by western blot. Results The result of MTT showed that compared with the control group, amlodipine uncommonly inhibit the proliferation of human breast carcinoma MCF-7 cells and both in a dose and time-dependent manner; The IC50 was 14.439μmol/L after have been treated with amlodipine for 48h.The consequent of FCM illustrated that amlodipine would make breast cancer MCF-7 cells arrested in G1 phase. When breast cancer MCF-7 cells were treated with amlodipine in the end does 7.22μmol/L (1/2IC50), 14.439μmol/L (IC50) and 28.88μmol/L (2IC50) for 48h, the ratios in the G0/G1 phase were significantly increased as compared with control group(P<0.05).Meanwhile, after treated with amlodipine under the same conditions, compared whit the control group, the test results of immunocytochemistry, RT-PCR and western blot showed us clearly that amlodipine decreased the expression of mRNA and protein of cyclinD1, while increased the expression of mRNA and protein of p21 and so did the protein expression of p53.Conclusions Calcium channel blocker (CCB)-amlodipine exhibited obvious antitumor activities on human breast carcinoma MCF-7 cells , it was the role by regulating the cell cycle, reduced cells from G1 phase to S phase and so that cells were blocked in G1 phase; the role of G1 phase arresting might be related to regulate the expression of mRNA and protein of cycle-related gene cyclinD1, p21 and p53.