| BackgroundMultiple myeloma(MM)is a plasma cell malignant proliferative disease,which is the second largest hematological malignancy.Abnormal monoclonal plasma cells infiltrate related organs and soft tissues,and secretes monoclonal immunoglobulin or its Fragments(M proteins)which cause damage.The main clinical manifestations are bone destruction,anemia,hypercalcemia,renal insufficiency,infection,and amyloidosis.In recent years,with the advancement of chemotherapy regimens and the development of hematopoietic stem cell transplantation,the survival time of patients has beenprolonged.But due to individual differences,tumor resistance and other factors,it can not be cured at present.In addition,some patients with multiple myeloma do not respond to the current treatment and are unable to control further progress of the disease,which seriously jeopardizes the quality of the patient's life.So it is necessary to further search for new drugs and target treatment.Metformin is a widely used biguanide oral anti-diabetic drug.Recent studies have shown that metformin can reduce the risk of tumors development and improve the prognosis of the tumor.In vitro experiments have shown that metformin can inhibit the proliferation of tumor cells such as malignant gynecological tumors,lung cancer,etc.In this study,human multiple myeloma cell line U266 was treated by metformin to observe its effect on cell proliferation,in order to explorered the molecular mechanism of metformin for multiple myeloma.ObjectiveMetformin(Met)can inhibit the proliferation of tumor cells in vitro,with little knowledge of effects on multiple myeloma.The purpose of this study was to investigate the effect and molecular mechanism of metformin on human myeloma cell line,U266 cells.MethodsU266 cells were treated with different concentrations of Metformin,MTT was used to detect cell proliferation.The PI staining was used to detect the cell cycle.And the expression of BCL-2 family protein and the release of cytochrome C were assessed by western blot.Results1.Metformin had inhibitory effect on the proliferation of U266 cells in the range of 5~50 mmol/L,and the inhibitory rate was significantly higher than that of the control group at 24,48,and 72 h after each concentration.The rate increased with increasing concentration(r values at the concentrations of 0.948,0.953,and 0.851 for24,48,and 72 h at each concentration).2.After metformin treated U266 cells for 48 h,the proportion of G0/G1 phase cells increased,and the proportion of S phase cells decreased.The cells were treated with10 and 20 mmol/L metformin for 48 h,G0/G1 phase.The proportion of cells was63.5% and 89.2%,respectively,while the blank control group was 52.8%.It was suggested that U266 cells were arrested in G1 phase after 48 h of metformin treatment(P<0.05).3.Compared with the control group,the expression of BCL-2 and BCL-Xl in U266 cells treated with metformin decreased for 48 hours,but the protein expression of BAX increased,the difference was statistically significant(P<0.05).The protein cleavage of the downstream apoptotic signaling protein PARP is enhanced.In addition,the amount of cytochrome C released from the mitochondria to the cytoplasm was increased by Metformin(P<0.05).ConclusionIn this study,different concentrations of metformin were applied to the myeloma cell line U266.MTT assay was used to detect the cell proliferation inhibition rate and PI staining to detect the cell cycle.The expression of BCL-2 protein family protein and the release of cytochrome C were detected by Western blot.By comprehensive analysis of the data obtained,the main findings are as follows:1.Metformin can inhibit U266 cell proliferation and induce apoptosis.2.The mitochondrial apoptosis pathway may be one of the mechanisms by which metformin induces apoptosis. |
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