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Exp Oncol. 2004 Jun;26(2):111-7.

Comparative study of human breast carcinoma MCF-7 cells differing in their resistance to doxorubicin: effect of ionizing radiation on apoptosis and TGF-beta production.

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Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv 79005, Ukraine.



The aim of the study was to investigate the survival and growth of human breast carcinoma MCF-7 cells with different sensitivity to doxorubicin and production of transforming growth factor beta-(TGF-beta) in dependence on the dose- and duration of X-ray in order to check if the cross-resistance to doxorubicin and radiation effects exists.


Determination of cell number and valiability using trypan blue (0.1% (w/v)) exclusion method, Western blot analysis of p53 protein expression, biological testing of TGF-beta activity, lectinocytochemical analysis for apoptosis quantitative estimation in unirradiated and irradiated cells of both sublines of MCF-7 cells--sensitive (MCF-7(wt)) and resistant (MCF-7(DOX/R)) to doxorubicin.


It was found that doxorubicin-resistant breast cancer cells were also more refractory to X-radiation-dependent growth inhibition. There were revealed different effects of distinct doses of X-ray on p53 protein expression by cells of both sublines. The level of production of TGF-beta was compared in non-irradiated MCF-7 cells and in these cells exposed to X-radiation. It was shown that X-radiation increased TGF-beta activity in the conditioned medium of the irradiated cells of both doxorubicin-sensitive and -resistant lines.


The results of our study suggest that the biological effects of X-radiation on human breast cancer MCF-7 cells can be at least partly mediated by TGF-beta. Taking into account that TGF-beta is a potent natural immunosupressor, one may consider that an increased activity of this cytokine can intensify negative effects of X-radiation.

[Indexed for MEDLINE]

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