C4A and chondrosarcoma: Based on these data, chondrosarcoma cells were treated with 10 μM of Bcl-2 inhibitor, 10 μM of C-4 (P-glycoprotein inhibitor) or 10 μM of embelin (XIAP inhibitor) and two different concentrations of doxorubicin (0.1 μM and 1 μM).