EXPRESSION OF mRNA CODING FOR TGF-b AND ITS RECEPTORS IN IRRADIATED HUMAN BREAST CARCINOMA MCF-7 CELLS DIFFERING IN THEIR SENSITIVITY TO DOXORUBICIN
Aim: The effect of X-irradiation on the expression of mRNAs coding for transforming growth factor b (TGF-b) and its receptors was compared in human breast carcinoma MCF-7 cells differing in their sensitivity to doxorubicin. Methods: Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used for the estimation of mRNAs expression for TGF-b1, TGF-b2 and TGF-b type I and II receptors in the unirradiated and irradiated cells of two sublines of MCF-7 cells — sensitive (MCF-7(wt)) and resistant (MCF-7(DOX/R)) to doxorubicin. Results: X-irradiation caused an increase in TGF-b1 coding for mRNA expression in both breast cancer cell lines tested and an elevation of TGF-b2 mRNA expression in doxorubicin-resistant subline. The down-regulation of TGF-b type I and II receptors in the irradiated MCF-7(DOX/R) cells was revealed at the transcriptional level. Conclusions: The results of our study show that the development of refractoriness of used tumor cells to anti-cancer drug doxorubicin, at least partly, can be caused by the impairment in TGF-b signaling pathway.
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