Research On Relative Effect Between Glucose Transporter 1 And Breast Cancer Chemoresistance

Background:Breast cancer has become the most frequently diagnosed cancer and the leading causes of malignant tumor death in women.About 90%treatment failure of cancer patients,including breast carcinoma,is believed due to resistance to chemotherapy.Aerobic glycolysis has been identified as one of the most important hallmarks of cancer that distiguished from normal tissue cells.There are many researches showing that high glucose consumption and GLUTs expression related to a higher grades of malignant tumor and a worse prognosis.Besides,a planty of articles also demonstrated the association between high aerobic glycolysis,GLUTs overexpression and chemoresistance or radioresistance of cancer cells.GLUT1 is in charge of glucose transporting in the majority of different tissue original cancer types.Object:To observe the glucose consumption rate and GLUT1 expression variation between human breast cancer cell adriamycin-resistance cell lines and parental cell lines,therefore to explorate the adriamycin sensibility changes of using drug which inhibites the function of GLUT1 and try to investigate the mechanism behind it.Methods:The adriamycin resistant cell line MCF-7/ADR was developed by stepwise selection for resistance with increasing concentration of adriamycin.Measuring the adriamycin’s and WZB117’s IC50 of adriamycin-resistance cell lines and parental cell lines,analysing the glucose consumption of 72h and GLUT1 expression changes between them.Chosing the low toxicity WZB117 concerntrations to combine adriamycin concerntration gradients to test the adriamycin IC50 variation of MCF-7/ADR.Comparing the apoptotic rates,migration rates,growing ability,glucose consumptin rate,lactate producing rates of 0.5μg/ml adriamycin-only group,10μM WZB117 only-group,0.5μg/mladriamycin and 10μM WZB117 conbination group with the control group.Testing AMPK/mTOR signalling pathway and BCL-2 protein family expression changes of these four groups.Results:1.The MCF-7/ADR developed by stepwise increasing concentration of adriamycin adriamycin IC50 was(21.88±1.0)μg/ml,the parental ones’ was(0.29μ0.1)μg/ml,RI was 75.44;the second and third day growth speed and glucose consumption rate of MCF-7/ADR cell line were significantly higher than its parental competitor(p<0.05).GLUT1 was overexpressed in MCF-7/ADR cell line.2.The 72h WZB117 IC50 of MCF-7/ADR cell line was 257.04μ3.4μM;5μM WZB117 combinated with adriamycin for 72h made the IC50 became 0.29±0.1μg/ml,10μM WZB117 combinated with adriamycin for 72h made the IC50 became 1.18±0.8μg/ml,RF were 2.71 and 18.54 respectively,achieved significantly resensitization of MCF-7/ADR(P<0.01).The combination of these two drugs could significantly increase the apoptotic rate(P<0.01);adriamycin-only group,combination group cell proliferation rate were much lower than the control group(P<0.01),but the adriamycin-only group proliferation rate in the third day was accelerated and higher than combination group(P<0.01);WZB117-only group and combination group colony number were significantly lower than adriamycin-only group and control group.Adriamycin could inhibite MCF-7/ADR cell’s migrating ability more significantly than WZB117(P<0.05),but the combination of two agents did not exhibit improved migrating ability inhibition.3.The glucose consumpution rate of WZB117-only group and combination group in 72h were significantly lower than control group(P<0.05);adriamycin did not make influence on glucose consumpution.However,adriamycin alone could lead to a higher lactate producing rate(P<0.01);WZB117 alone or the combiantion of these two drugs could significantly decrease lactate producing rate(P<0.01).After MCF-7/ADR cells treated for 48h,phosphorated AMPK and phophorated mTOR level in WZB117-only group and combination group was higher than rest two groups.More importantly,adriamycin-only group,WZB117-only group and combination group promoted BAX translocated to mitochondria but WZB117-only group and combination group exhibited a much more translocation of BAX;what’s more,cellular BCL-2 level did not change under in these four groups.Conclusion:1.Adriamycin IC50,proliferation rate,glucose consumption rate,GLUT 1 level of MCF-7/ADR developed by stepwise increasing concentration was higher than parental cell line.2.Inhibiting GLUT1 function of MCF-7/ADR by using WZB117 could enhance the cytotoxity of adriamycin,decrease adriamycin IC50,thus achieving the aim of resensitization partially.3.WZB117 could inhibite the aerobic glycolysis of MCF-7/ADR treated by adriamycin.The mechanism of improving cytotoxity of adriamycin by WZB117 was via activation of AMPK and inhibition of mTOR,BAX translocation to mitochondria in all likelihood.