[Effects of D-limonene on leukemia cells HL-60 and K562 in vitro]

To investigate the effects of D-limonene (D-L) on the cell growth and apoptosis in HL-60, K562 cells and to elucidate its mechanism, the influence of D-L on proliferation of HL-60 and K562 cells was determined by propidium iodide assay, the expression levels of mutant p53, bcl-2, bax gene were detected by cell morphological analysis, flow cytometry and immunohistochemistry staining, the D-L-inducing HL-60 and K562 cell apoptosis in vitro was observed systematically. The results showed that D-L inhibited HL-60 and K562 cell growth in a dose- and time-dependent manner with the IC50 of 0.75 mmol/L similarly, D-L induced apoptosis of HL-60 and K562 cells, and expression of bcl-2 gene was down regulated by D-L in a concentration-dependent manner in HL-60 cells. The bcl-2, mutant type of p53 genes were down regulated while bax gene was up regulated by D-L in a concentration-dependent manner in K562 cells. It is concluded that D-L can inhibit proliferation and induce apoptosis of HL-60 and K562 cells. The bcl-2, mutant type of p53 and bax may be involved in the gene regulation of D-L-induced apoptosis.