Effective cytotoxicity against human leukemias and chemotherapy-resistant leukemia cell lines by N-N-dimethylsphingosine.

We evaluated the cytotoxicity of dimethylsphingosine (DMS) against four human leukemia cell lines: two acute (HL60 and a multi-drug resistance MDR-positive derivative HL60-dox) and two blast crisis chronic myelogenous leukemias (JFP1, from a treatment refractory patient and K562), and against blasts isolated from 11 leukemia patients. Cell line viability decreased proportionally to DMS concentration and treatment time (P<0.001).