The Synergistic Antitumor Activity Of Vitamin D3 Combined With Metformin In Human Breast Carcinoma MDA-MB-231 Cells And Human Bladder Carcinoma SW-780 Cells

Part OneThe synergistic antitumor activity of vitamin D3 combined with metformin in human breast carcinoma MDA-MB-231 cells and its molecular mechanismsObjective:To study the effects of vitamin D3 combined with metformin on the apoptosis induction and its mechanism in breast cancer cell line MDA-MB-231.Methods:MTT assay and fluorescence microscope observations were used to study the apoptosis induction of MDA-MB-231 cells by vitamin D3 combined with metformin in vitro.The expressions of p-Bcl-2,Bax,Cleaved caspase-3,c-Myc and related signaling pathways activated protein p-IGF-IR,p-AMPK,p-mTOR,p-S6,p-P70S6K were examined using Western blotting.Results:Vitamin D3 280 μg/ml or vitamin D3 300 μxg/ml or vitamin D3 320 μg/ml combined with metformin 15000 μg/ml acted on MDA-MB-231 cells for 24 h,and the results exhibited significant growth inhibition.Compared with the negative control group,vitamin D3 and metformin monotherapy treatment groups can cause a certain degree of apoptosis,but the apoptotic features of combination treatment group is significant,the apoptosis rate is increased greatly.Compared with the negative control group and monotherapy treatment groups,expressions of p-Bcl-2,c-Myc,p-IGF-IR,p-mTOR,p-P70S6K and p-S6 in combination treatment group significantly decreased,whereas expressions of Bax,Cleaved caspase-3 and p-AMPK significantly increased.Conclusion:Vitamin D3 combined with metformin exhibits obvious inhibitory effects on cell proliferation and apoptosis induction in MDA-MB-231 cells.The underlying anti-tumor mechanisms may be related to activating expression of Cleaved caspase-3,Bax and p-AMPK,as well as inhibiting expressions of p-Bcl-2,c-Myc,p-IGF-IR,p-mTOR,p-P70S6K,p-S6.Part TwoVitamin D3 enhances apoptosis-inducing effects of metformin in human bladder carcinoma SW-780 cellsObjective:To study the effects of vitamin D3 combined with metformin on the proliferation and apoptosis in human bladder cancer cell line SW-780 and its possible mechanism.Methods:MTT assay and fluorescence microscope observations were used to study the effects of vitamin D3 combined with metformin on the proliferation and apoptosis of SW-780 cells in vitro.Western blot was used to detect the expression of apoptosis-related proteins p-Bcl-2,Bax,Cyclin D1,c-Myc and related signaling pathways activated proteins p-IGF-IR,p-mTOR,p-P70S6K,p-S6.Results:MTT results show that 320 μg/ml vitamin D3 combined with 620 μg/ml metformin acting on cells for 48h had a significant synergistic effect on proliferation.Fluorescence microscope observations show that compared with negative control group and monotherapy treatment group,the apoptosis features of combination treatment was obviously and the apoptosis rate is increased greatly.Western blot showed that compared with the negative control group and monotherapy treatment group,the expression levels of p-Bcl-2,Cyclin D1 and c-Myc in combination treatment group significantly decreased,whereas the expression level of Bax significantly increased,and the expression levels of p-IGF-IR,p-mTOR,p-P70S6K and p-S6 in combination treatment group significantly decreased.Conclusion:Vitamin D3 combined with metformin exhibit obvious inhibitory effects on the cell proliferation and apoptosis induction in SW-780 cells.The underlying anti-tumor mechanism may be related to inhibiting the expressions of p-Bcl-2,Cyclin D1,c-Myc,p-IGF-IR,p-mTOR,p-P70S6K,p-S6 and activating the expression of Bax.