(a) Dose-response effects of CoCl2 on mouse +SA mammary tumor cell viability. +SA cells were initially plated at a density of cells/well in 96-well culture plates (8 replicates/group) and exposed to 0–300 µM CoCl2 for a 24 hr incubation period. Afterwards, viable cell number was determined using the MTT assay. (b) Effects of 150 µM CoCl2 (noncytotoxic dose) alone and in combination with subeffective antiproliferative doses (2 µM) of -tocotrienol or the -tocotrienol oxazine derivative, compound 44, on +SA mammary tumor cell viability. +SA cells were initially plated at a density of cells/well in 96-well culture plates (8 replicates/group) and their respective treatments for a 24 hr incubation period. Afterwards, viable cell number was determined using the MTT assay. Vertical bars indicate mean viable cell number ± SEM. compared to the vehicle-treated control group.
