Overexpression of granulocyte macrophage colony stimulating factor in breast cancer cells leads towards drug sensitization.

This report describes the effect of overexpressing granulocyte macrophage colony stimulating factor (GMCSF) in breast cancer cells, which otherwise is involved in proliferation and differentiation of granulocyte and macrophage lineages. The purified recombinant GMCSF cytokine is known to exert dose-dependent proliferative response on various cancer cells, but its effect during overexpression is yet to be evaluated. In our present study, we have generated MCF-7 (breast cancer) cells overexpressing GMCSF. Interestingly, cell viability studies showed pronounced sensitivity of GMCSF overexpressing MCF-7 cells towards anticancer drugs, such as, doxorubicin, 5FU and cisplatin. These findings were substantiated by cell cycle analysis of the drug-treated GMCSF overexpressing MCF-7 cells. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) results revealed differential expressions of cyclins, and the carboxyfluorescein succinimidyl ester (CFSE)-based assay established decrease in doubling time of GMCSF overexpressed cells with respect to the control populations. Thus, overexpressing of proliferative GMCSF cytokine in breast cancer cells may increase susceptibility to anticancer drugs.