LBSO potentiate the effects of Hg in breast cancer cells

Abstract

Breast cancer is the second major cause of death in women. Reports show that breast cancer cells have high level of glutathione. This research was done to characterize the kinetic signature and mechanism of cell death using the oxidative stress pathway when mercury (Hg) and L‐buthionine sulphoximine (LBSO, inhibits glutathione production) are presented to MCF‐7 cells. The hypothesis tested is that the potentiating effects of LBSO will be higher with Hg than with As. Production was inhibited by treating the MCF7 cell line with 2.5 mM (LBSO) and then exposed to mercury 5.4ppm Hg. The cytotoxic effect was studied in real time using Real Time Cell Electronic Sensing (RTCES). To determine the oxidative stress pathway used, mitochondrial transmembrane potential (∆øm), Reactive Oxygen Species (ROS), superoxide anion and Glutathione (GSH) levels were studied using Rhodamine123 fluorescent (Rho123), 2′,7′‐Dichlorodihydrofluorescein (H2DCFDA), Dihydroethidium (DHE), 5‐Chloromethylfluorescein diacetate (CMFDA) dyes respectively. Each sample, 10,000 events were collected using FACSCalibur flow cytometer. ROS and O2 • levels were expressed as mean fluorescence intensities (MFI), calculated with CellQuest. The results did not show a vast difference between Hg and LBSO and Hg alone. Results reveal that Hg might be a better candidate for cancer therapy compared to As due to As high toxicity.