Chorna I. Effect of ionizing radiation and anticancer drugs on regulatory system of transforming growth factor beta in breast carcinoma cells differing in their resistance to doxorubicin

Object - the transforming growth factor ? signaling system in human breast carcinoma MCF-7 cells treated with extremal factors; methods - biochemical, cytological, statistical; results - it was found that the development of refractoriness to doxorubicin in MCF-7(DOX(R) cells was accompanied by loss of their sensitivity to X-radiation-dependent growth inhibition and apoptosis induction; X-irradiation caused an increase in expression of mRNA coding for TGF-? and an elevation of secretion of TGF-? in MCF-7(wt) and MCF-7(DOX(R) cells; the refractoriness of MCF-7(DOX(R) cells to X-rays could be, at least partly, explained by the impairment in TGF-? signaling pathway; anticancer drugs doxorubicin, methotrexate, cisplatin induced an decrease in the level of TGF-? receptor type I mRNA in MCF-7(DOX(R) cells and an decrease in the level of TGF-? receptor type II mRNA in MCF-7(wt) and MCF-7(DOX(R) cells; introduction in Lviv national university; branch - biology.