Objective    To explore the apoptotic effect of benzyl isothiocyanate (BITC) on human leukemia cells and investigate its related molecular mechanism.     Methods     Cells (U937

Jurkat and HL60) were exposed to BITC at various concentrations (0

2

4

6 or 8  μmol/L) for 6 h or 12 h

or at 8  μmol/L for different time intervals. The apoptosis was measured using flow cytometry. The apoptotic-related proteins

such as Caspase-3

poly ADP-ribose polymerase (PARP)

myeloid cell leukemia-1 (Mcl-1) and so on

were determined using Western blot assay.     Results    BITC induced apoptosis in human leukemia cells in dose- and time-dependent manners. BITC at a dose over 4  μmol/L began to induce an increased expression of Caspase-3 protein and decreased expression of PARP in U937 cells

and when the dose was 8  μmol/L

the changes reached their summits respectively. The expression of anti-apoptotic protein Mcl-1 was decreased in U937 cell after exposure of BITC.     Conclusion    BITC induces apoptosis in human leukemia cells including U937

Jurkat and HL60

and downregulation of Mcl-1 may play an important role in BITC-induced apoptosis.