Ketoconazole-induced JNK phosphorylation and subsequent cell death via apoptosis in human osteosarcoma cells

This study examined the effect of ketoconazole on viability, apoptosis, mitogen-activated protein kinases (MAPKs) and Ca²⁺ levels in MG63 osteosarcoma cells. Ketoconazole at 20–200 μM decreased cell viability via apoptosis as demonstrated by propidium iodide staining and activation of caspase-3. Immunoblotting suggested that ketoconazole induced phosphorylation of ERK and JNK, but not p38, MAPKs. Ketoconazole-induced cell death and apoptosis were partially reversed by the selective JNK inhibitor SP600125, but not by the selective ERK inhibitor PD98059, suggesting that ketoconazole’s cytotoxic action was via JNK, but not via ERK and p38 MAPKs. Ketoconazole at a concentration of 100 μM induced [Ca²⁺]_i increases. Chelation of intracellular Ca²⁺ with 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) totally inhibited ketoconazole-induced [Ca²⁺]_i increases without reversing ketoconazole-induced cell death. Collectively, in MG63 cells, ketoconazole induced cell death and apoptosis via evoking JNK phosphorylation in a Ca²⁺-independent manner.