Effects of Antrodia camphorata on viability, apoptosis, [Ca ²⁺]_i, and MAPKs phosphorylation in MG63 human osteosarcoma cells

The present study explored the effect of Antrodia camphorata (AC) on viability, apoptosis, mitogen-activated protein kinases (MAPKs) phosphorylation, and Ca²⁺ regulation in MC63 human osteosarcoma cells. AC (25-50 μg/ml) did not affect cell viability, but at 100-200 ng/ml decreased viability and induced apoptosis in a concentration-dependent manner. AC at concentrations of 25-200 μg/ml did not alter basal [Ca²⁺] _i, but at 25 μg/ml decreased [Ca²⁺], increases induced by ATP, bradykinin, histamine, and thapsigargin. ATP, bradykinin, and histamine increased cell viability while thapsigargin decreased it. AC (25 μg/ml) pretreatment failed to alter bradykinin- and thapsigargin-induced effects on viability, but potentiated ATP- and histamine-induced increases in viability. Immunoblotting showed that MC63 cells did not have background phospho-JNK and phospho-p38 mitogen-activated protein kinases (MAPKs); and AC did not induce the phosphorylation of these two MAPKs. Conversely, the cells had significant background phospho-ERK MAPK that was inhibited by 200 ng/ml AC. The ERK-specific inhibitor PD98059 also induced cell death. Collectively, in MC63 cells, AC exerted multiple effects on viability and [Ca²⁺]_i, caused apoptosis probably via inhibition of ERK MAPK phosphorylation.