Recombinant human interleukin 24 reverses Adriamycin resistance in a human breast cancer cell line

Background the major cause of multidrug resistance is over-expression of membrane p-glycoprotein (p-gp). we investigated the effect of recombinant human interleukin 24 (rhil-24) on the adriamycin (adm)-resistant human breast cancer cell line mcf-7/adm. methods the cytotoxicity of rhil-24 and adm was determined by 3-[4,5-dimethylthiazol-2-yl],5-diphenyl tetrazolium bromide (mtt) assays. the expression of p-gp was assessed by confocal microscopy and western blot analysis. results the ic50 values for rhil-24 in mcf-7/wild-type and mcf-7/adm cells were 0.17 and 14.6 μm,respectively. the ic50 value of adriamycin in mcf-7/adm cells decreased in a dose-dependent manner when rhil-24 was used. the resistance modulating factor (rmf) was directly proportional to the dose of rhil24. adm accumulation increased while p-gp expression decreased at a low dose (4 μm) of rhil24 in mcf-7/adm cells. the expression of p-gp was decreased at 4 μm in confocal microscopy and western blot analysis. conclusions rhil-24 circumvented the drug-resistance of mcf-7/adm cells via activation of the transcription factor stat 3. rhil24 has potential to act as a p-gp inhibitor to reverse adriamycin resistance in breast cancer. © 2014 institute of pharmacology,polish academy of sciences.