OBJECTIVETo investigate the effects of angular pyranocoumarin (±) -4'-O- acetyl-3'-Oangeloyl- cis- khellactone (APC) extracted from peucedanum praeruptoruon on the proliferation and apoptosis of U266 cells, and to explore its related mechanism.

METHODSAPC was extracted by petroleum ether technique, and its purity was tested by high performance liquid chromatography, and its chemical structure was identified by magnetic resonance spectroscopy. U266 cells were treated with APC in various concentrations (0, 10, 20, 30, 40 μg/ml）for different durations（24 and 48 h). The inhibitive effect of APC on cell growth was detected by CCK-8 method. After U266 cells were incubated with APC（0, 10, 20, 30, 40 μg/ml）for 24 h, the apoptosis of cells were observed by flow cytometry stained with Annexin Ⅴ/PI and Hochest33342; the expression levels of caspase-3, 8, ERK, p-ERK, AKT and p-AKT protein were assayed by Western blot; the expression of hTERT mRNA was measured by RT-PCR.

RESULTSThe purity of APC identified by magnetic resonance imaging was 98.8%. The proliferation of U266 cells was inhibited, and the apoptosis was induced in a time- and/or dose- dependent manner after treatment with APC. APC could upregulate the caspase- 8, 3 protein expression and downregulate the p- ERK, p-AKT protein expression along with the increase of APC dose. APC also could downregulate the hTERT mRNA expression.

CONCLUSIONAngular pyranocoumarin APC could inhibit the proliferation and induce the apoptosis of U266 cells. The probable mechanism might be achieved by upregulating caspase-8, 3 protein expression and downregulating p-ERK, P-AKT protein and the hTERT mRNA expression.