The Effects On Fatty Acid Synthase Expression In Breast Cancer Cells MCF-7Cultured By High Glucose And High Insulin And Interventional Study With Metformin

Objective:Fatty acid synthase (FASN) is a key enzyme in the de novo synthesisfatty acid in the cells and involves in energy metabolism. FASN is highlyexpressed in lipogenic tissues such as liver,adipose tissue and low orundetectable levels in other tissues. Recent studies found that FASN issignificantly upregulated in many common human tumor tissues withincreased activity, and seriously affects cancer prognosis. Type2diabetesmellitus is a common disease. Epidemiological studies found that diabeticpatients is associated with a high risk of incident cancers (including breastcancer), and diabetes is a risk factor to the cancers with poor prognosis. TheBenefits of metformin for the treatment of type2diabetes also has been foundto reduce the risk of some certain cancers, the mechanism is unclear. In thisstudy, We observed the expression of FASN in breast cancer cells MCF-7cultured in high concentration of glucose and/or insulin,to explore the possiblerole of FASN may exist between diabetes and cancers. To investigate theeffects of metformin intervention on the expression of FASN protein andmRNA in MCF-7cells，and the possible mechanisms of drug action.In orderto provide a new research direction to improve the prognosis of patients withtumor and prolong lifespan.Method:Breast cancer cells MCF-7were maintained in DMEM/low glucosemedium containing10%fetal bovine serum for48h,than divided into fourexperimental groups with fresh serum-free DMEM containing glucose and/orinsulin for another48h(Normal glucose group: the concentration of D-glucosewas5mmol/L, and the concentration of insulin was0mU/L; high glucosegroup: the concentration of D-glucose was20mmol/L, the concentration of insulin was0mU/L; high insulin group: the concentration of D-glucose was5mmol/L, the concentration of insulin was125mU/L; high glucose and insulingroup: the concentration of D-glucose was20mmol/L, the concentration ofinsulin was125mU/L).And then replaced fresh culture medium containingdifferent concentration of metformin（0mmol/L，2.5mmol/L，5mmol/L，10mmol/L，20mmol/L）respectively.The cells further cultured for another12h,than harvested to extract total protein and total RNA, took theconcentration of metformin0mmol/L for the control group.Detect theexpression of FASN protein and mRNA by the methods of Western blot andRT-PCR.Result:1The expression of the FASN protein and mRNA in MCF-7cellscultured in different groupsCompared with control group,the expression of FASN protein and mRNAwas increased in high glucose and/or high glucose groups with statisticalsignificant (P＜0.05).2The effect of metformin on the expression of the FASN in MCF-7cellsin different groups2.1In the normal glucose group,The effect of metformin on theexpression of the FASN in MCF-7cellsCompared with control group, the expression of FASN protein andmRNA were not changed by various concentration of metformin,with nostatistically significant(P＞0.05).2.2In high glucose group, the effect of metformin on the expression ofthe FASN in MCF-7cellsCompared with control group,the expression of FASN protein and mRNAwere not changed by various concentration of metformin,with no statisticallysignificant(P＞0.05).2.3In high insulin group, the effect of metformin on the expression of theFASN in MCF-7cells2.3.1The effect of metformin on the expression of the FASN protein Metformin treatment led to a dose-dependent decrease the expression ofFASN protein.Compared with the control group,there were no significantdifference in the concentration of metformin2.5mmol/L and5mmol/L groupsof the expression of FASN protein (P＞0.05).There were significant differencein the concentration of metformin10mmol/L and20mmol/L metformingroups,the expression of FASN protein decreased (P＜0.05).2.3.2The effect of metformin on the expression of the FASN mRNAMetformin treatment led to a dose-dependent decrease the expression ofFASN mRNA.Compared with the control group, there were no significantdifference in the concentration of metformin2.5mmol/L and5mmol/L groupsof the expression of FASN mRNA (P＞0.05).There were significant differencein the concentration of metformin10mmol/L and20mmol/L metformingroups,the expression of FASN mRNA decreased (P＜0.05).2.4In high glucose and insulin group, the effect of metformin on theexpression of the FASN in MCF-7cells2.4.1The effect of metformin on the expression of the FASN proteinMetformin treatment led to a dose-dependent decrease the expression ofFASN protein. Compared with the control group,there were no significantdifference in the concentration of metformin2.5mmol/L and5mmol/L groupsof the expression of FASN protein (P＞0.05).There were significant differencein the concentration of metformin10mmol/L and20mmol/L metformingroups,the expression of FASN protein decreased (P＜0.05).2.4.2The effect of metformin on the expression of the FASN mRNAMetformin treatment led to a dose-dependent decrease the expression ofFASN mRNA. Compared with the control group, there were no significantdifference in the concentration of metformin2.5mmol/L and5mmol/L groupsof the expression of FASN mRNA (P＞0.05).There were significant differencein the concentration of metformin10mmol/L and20mmol/L metformingroups,the expression of FASN mRNA decreased (P＜0.05).Conclusion:1. High glucose and/or high insulin can upregulate the expression of FASN protein and mRNA in MCF-7cells.2. Metformin treatment led to a dose-dependent decrease the expressionof FASN protein and mRNA in MCF-7cells cultured in high glucose andinsulin.