ABSTRACT
<p><b>OBJECTIVE</b>To explore the mechanism of shikonin for inducing the apoptosis of human promyelocytic leukemia cell HL-60.</p><p><b>METHODS</b>The effects of shikonin on the HL-60 cell proliferation were detected using MTT. The apoptosis rate was analyzed by Annexin-V/PI double staining. The expression level of the bcl-2 gene was detected using semi-quantitative reverse transcriptase PCR (RT-PCR), thus analyzing the correlation between the bcl-2 expression level and the apoptosis of HL-60.</p><p><b>RESULTS</b>Shikonin could inhibit the proliferation of HL-60 cells with the concentration range of 1-8 microg/mL in a time- and concentration-dependent manner. Two microg/mL shikonin could induce the apoptosis of HL-60 cells in a time-dependent manner. The expression level of bcl-2 was obviously down-regulated at 2 microg/mL shikonin.</p><p><b>CONCLUSIONS</b>Shikonin could induce the apoptosis of HL-60 cells. Its mechanism was correlated with down-regulation of the expression level of bcl-2.</p>