[Effects and its mechanism of quercetin on cervical cancer HeLa cells]

To evaluate the effects of quercetin on HeLa cells proliferation and study the mechanism of apoptosis.

The proliferation of HeLa cells treated with quercetin at different concentrations (6.25, 12.5, 25, 50 micromol/L) for 24 hours was assessed by methyl thiazolyl tetrazolium (MTT) method, and also observe the inhibitory effect of quercetin on the transplanted carcinoma in BALB/ C nude mice. Cell apoptosis rate was detected by flow cytometry with annexin V- fluorescein isothiocyannate (FITC)/propidium iodide (PI) technology. The changes of intracellular calcium ion concentration ([Ca2+]i) and mitochondrial membrane potential in HeLa cells induced by quercetin were studied by laser confocal fluorescence microscope and specificity fluorescent probes of Fluo-3/AM and JC-1. Colorimetric method was used to measure the activity of caspase-3.

After treated by different concentrations of quercetin (6.25, 12.5, 25, 50 micromol/L), the proliferation was inhibited and the apoptosis was induced in HeLa cells with the inhibition rate of (13.4 +/- 2.2)%, (26.2 +/- 6.8)%, (39.8 +/- 11.4)% and (48.5 +/- 9.1)% respectively, and with the apoptosis rate of (9.0 +/- 1.4)%, (13.3 +/- 1.1)%, (22.5 +/- 2.3)% and (44.7 +/- 4.2)% respectively, and which effects were dose-dependent (P < 0.01). Treated by different concentrations of quercetin (25, 50, 100 mg kg(-1) d(-1)), the growth of transplanted tumor in nude mice was inhibited with the inhibition rate of 13.4%, 30.4%, 45.8%. The apoptosis of HeLa cells was induced by quercetin, which markedly reduced mitochondrial membrance potential, effectively enhance [Ca2+]i, and the caspase-3 was activated in a dose-dependent manner (P < 0.01).

Quercetin can significantly inhibit the proliferation of HeLa cells, which may be induced apoptosis of cervical cancer cells via the Ca2+ -dependent mitochondrial apoptosis pathway.