Assessment of purging with multidrug resistance (MDR) modulators and VP-16: results of long-term marrow culture.


We studied the effects of two modulators of multidrug resistance (MDR), cyclosporine and verapamil, on the cytotoxicity of etoposide (VP-16) in normal bone marrow cells. VP-16 was toxic to normal bone marrow at concentrations greater than 50 microM, resulting in no granulocyte-macrophage colony-forming units (CFU-GM) in short-term methylcellulose cultures… (More)