| Grapes in genus Muscadinia Mixch., one of the genera within family Vitaceae, were indigenous to the southeastern region of USA. They had been bred for fresh fruit and processing in decades and successfully introduced to China by our lab recently. Muscadine grape had the strongest resistance to plant diseases and its fruit have plenty of phenolic chemicals including the unique phenolic compound called ellagic acid which presents a strong ability of anti-oxidation. In the present research, effects of fractions of pomace extracts from both Muscadinia rotundifolia ’Noble’ and Vitis vinifera ’Cabernet Sauvignon’ on breast cancer cells were examined, and the detail of the anticancer effects as well as the molecular mechanisms of each fraction among the ’Noble’ pomace extracts were evaluated further detail.Pomaces were extracted and separated into fractions. The fractions were then used to treat two strains of breast cancer cells, MDA-MB-231 and MCF-7. The effects on cell cycle arrest and apoptosis before and after treatment were analyzed by flow cytometry using PI staining and Annexin V-FITC/PI staining,respectively. The related cytokines were then evaluated using Western blot. The effects of fractions on cell invasion inhibition, anti-inflammation as well as ACE activity inhibition were tested. The results are as follows,1.Three fractions from both grapes were separated. For ’Noble’ pomace extracts, fraction 1 from contained mainly flavonoids and ellagic acid. Fraction 2 contained mainly tannins including procyanidin and ellagitannins while fraction 3 contained mainly anthocyanins and/or anthocyanidins and ellagic acid as well. The fraction 1 of’Cabernet Sauvignon’pomace extracts contained mainly organic acids and gallic acids, while fractions 2 and 3 contained procyanidin and anthocyanins and/or anthocyanidins, respectively.No ellagic acid or its derivatives were found in any fractions from the “Cabernet Sauvignon’ pomace.2.The results of cell viability assay and IC20 indicated that the effects of fractions from ’Noble’pomace extracts on MDA-MB-231 were stronger than those of MCF-7, and the ability listed in descending order was fraction 2>fraction 3>fraction 1; the fraction 2 from ’Cabernet Sauvignon’ pomace extracts on MCF-7 inhibition was more efficient than MDA-MB-231 while the inhibitory effects of the other two fractions on both two cancer cells were similar, and the ability listed in descending order was fraction 2>fraction 1>fraction 3.3.The results of cell cycle arrest and apoptosis assay showed that, for MDA-MB-231, all fractions of ’Noble’ pomace extracts can down-regulated the cyclin A proteins and cause S-phase arrest. Among all fractions, the ability to cause cell cycle arrest in descending order was fraction 2>fraction 3>fraction 1. Meanwhile, all fractions can induce apoptosis through activation of caspase 3, caspase 7 and caspase 9. The ability of apoptosis induction in descending order was fraction 3>fraction 1>fraction 2; for MCF-7, both fraction 2 and fraction 3 can cause S-phase arrest, and the fonner one has stronger ability than the latter one. Meanwhile, all fractions can induce necrosis of cancer cells, thus affecting the cell viability.4.Transwell invasion assay indicated that treatments of all fractions couldnot inhibit the invasive ability of both breast cancer cells. The anti-inflammation assay indicated all fractions could significantly reduce the level of NO, IL-6 and TNF-a, especially for the fraction 3. The ACE activity inhibition test suggested all fractions had an ability to reduce at least 60 % of the ACE activity.In conclusion, fractions of grape pomace extracts can inhibit the viabilities of breast cancer cells,and the fractions from ’Noble’ pomace can inhibit them through causing cell cycle arrest and inducing apoptosis or necrosis. Beisdes, it is possible that those fractions could reduce the occurrence by inhibiting imflammatory cytokines and ACE activity. The results showed a great potential of fractions to be anti-cancer agents or health beneficial products. |
PDF Full Text Request