The Suppressive Effect Of Cisplatin Combined With Hyperthermia On Human Breast Cancer Cell Lines Of Different ER Expression

Objective: To investigate the inhibition of hyperthermia, cisplatinand hyperthermia plus cisplatin on human breast cancer cell lines MCF-7and MDA-MB-453 which have different ER expression.Methods: 1,MCF-7 (ER positive) and MDA-MB-453 (ERnegative) were studied. Each kind of cell line would be divided randominto four groups: (1) Control group (C); (2) Cisplatin group (Ci)(Cisplatin was applied to cells for 24 hours whose concentration was 2, 4,8, 16, 32,64ug/ml); (3) hyperthermia group (H) (Cells were maintained at43'C for 60 minutes); (4) hyperthermia plus cisplatin group (H+Ci).2,The MTT assay has been developed for quantitative evaluation ofthe proliferation of the two cell lines and cytotoxicity of cisplatin with orwithout hyperthermia.3,The rate of clone formation was assayed by clone forming of tumorstem cells.Results:1,Both Hyperthermia and hyperthermia plus cisplatin hasthe suppressive effect on breast cancer cell lines. And the cytotoxicity ofhyperthermia plus cisplatin group was stronger than those of cisplatingroup and hyperthermia group.2,The IC50 values of cisplatin on human breast cancer cell MCF-7decreased from chemotherapy group 31.91μg/ml to hyperthermia pluscisplatin group 22.55μg/ml; The IC50 values on human breast cancer cellMDA-MB-453 decreased from cisplatin group 32.78μg/ml tohyperthermia plus cisplatin group 22.12μg/ml.3,The inhibition effect of cisplatin and hyperthermia plus cisplatinwas dose-dependent. When the concentration of cisplatin was 2μg/ml, theinhibition effect on cells was significant (p＜0.001). The difference between groups was significant (p＜0.001).4,The clone formation rate of hyperthermia plus cisplatin group waslower than that of cisplatin group. There was no clone formation whenconcentration of cisplatin in hyperthermia plus cisplatin group wasbeyond 16ug/ml, but 32ug/ml in cisplatin group.5,The heat sensitivity of the two breast cancer cell lines withdifferent ER expression status was not different statistically.Conelusion:1,Hyperthermia can significantly increase thesensitivity of breast cancer cells to cisplatin.2,Hyperthermia can be used for breast cancer with different ERexpression.