AIMTo study the antitumor mechanism of 3-bromopropionylamino benzoylurea (JIMB01) on leukemia and lymphoma.

METHODSThe antitumor effects of JIMB01 in cell culture was detected by MTT staining. JIMB01-induced apoptosis in leukemia and lymphoma cells was tested by Giemsa staining, fluorescent Hoechst33258 staining, as well as DNA gel electrophoresis. Cell cycle was analyzed by flow cytometry. JIMB01-induced Bcl-2 phosphorylation in CEM cell lines was detected by Western blot methods. The activities of caspase-3 and caspase-8 were determined by colorimetric protease assay and that of caspase-9 was determined by fluorescent intensity.

RESULTSThis compound showed antiproliferative activities in a panel of nine human leukemia and lymphoma cell lines with IC50 values in the range of 0.25 micromol x L(-10 to 0. 51 micromol x L(-1). Morphological observation and cell cycle analysis indicated that CEM cells were blocked at mitosis phase by JIMB01. The fluorescent Hoechst33258 staining showed apoptotic nuclear degradation dispersed in the cytoplasm of CEM cells exposed to JIMB01 at 0. 80 micromol x L(-1) for 24 h. DNA degradation in the form of a multiple-unit DNA ladder was clearly demonstrated in CEM leukemia cells treated with JIMB01 at 0.15 micromol x L(-1) or higher for 24 h using agarose gel electrophoresis. Bcl-2 phosphorylation became visible, in Western blot, within 6 h in CEM cells treated with JIMB01 at 0.15 micromol x L(-1) or higher for 24 h. JIMB01 increased the activities of caspase-3, -8 and -9 in CEM cells; DEVD-fmk, a caspase-3 inhibitor, inhibited the cytotoxicity of JIMB01 in CEM leukemia cells.

CONCLUSIONThe antitumor mechanism of JIMB01 is that JIMB01 may induce tumor cell apoptosis through Bcl-2 phosphorylation and then caspase passway.