Cytotoxic effect of graphene oxide-functionalized gold nanoparticles in human breast cancer cell lines

As the global burden of cancer is on the rise it is essential to develop alternate therapeutics that confer zero or minimum side effects. In this experiment, we evaluated the anticancer efficacy of graphene oxide-functionalized gold nanoparticles (GO-AuNPs) in human breast cancer cell lines MCF7 and MDA-MB-231. MTT assay revealed a dose-dependent decline in cancer cell survival. Significant alterations were detected in normal cellular morphology after treatment. Two different cell staining methods viz. acridine orange-ethidium bromide staining and annexin-cy3.18/6-carboxyfluorescein diacetate staining confirmed that the GO-AuNPs rendered their detrimental effect in cancer cells through apoptosis. To decipher the mode of apoptosis Western blotting was performed in which expression pattern of several proteins (PARP1, P53, P21, Bcl2, Bax, Caspase 9 and Caspase 3) established the intrinsic apoptosis pathway in these cell lines after GO-AuNP exposure. Intracellular calcium level, as measured by energy dispersive X-ray fluorescence analysis, was present at non-detectable level following treatment that can be linked to the cell cycle arrest and apoptotic cell death in them. Thus, GO-AuNPs were found effective in both types of human breast cancer cells viz. hormone-responsive MCF7 and chemoresistant MDA-MB-231 and can be considered as a highly potential anticancer agent in breast cancer therapy.