Abstract:

OBJECTIVE: To study the effect and mechanism of ginseng polysaccharide (GPS) on tamoxifen (TAM)-induced apoptosis in human breast cancer cells. METHODS： Human breast cancer cells MCF-7 were treated with different doses of GPS for 48 h. MTT assay was used to evaluate the minimal effective GPS dose. Then cells were treated with GPS at minimal effective dose combined with different doses of TAM. Bürgi formula was used to assess the synergy effect between GPS and TAM. Cellular mitosis was detected by Giemsa staining assay. Apoptosis was studied by DAPI staining analysis and flow cytometer. The expression of Fas，Caspase-9 and Parp was measured by Western blot. RESULTS：GPS at 40 μg/mL was the minimal effective dose on MCF-7 cells. Combined treatment of GPS at 40 μg/mL and TAM at 1 μg/mL showed the best effect in cell growth inhibition (q=1.82). Combination of GPS and TAM synergistically enhanced apoptosis of MCF-7 in comparison with GPS or TAM alone (q=2.19，P<0.05). Combinated treatment of GPS and TAM significantly inhibited cellular mitosis compared with GPS or TAM alone (P<0.05). Treatment of GPS+TAM induced increased level of Fas as well as cleavage of Caspases-9 and Parp. CONCLUSION：Combined treatment of GPS and TAM induced apoptosis in MCF-7 cell through Fas signal in a synergetic manner.

Key words: ginseng polysaccharide, tamoxifen, apoptosis, MCF-7 cells