Department of Food Science, University of Naples Federico II, Portici, Naples, Italy.
Mol Nutr Food Res. 2011 Feb;55(2):229-38. doi: 10.1002/mnfr.201000074. Epub 2010 Aug 19.
Milk proteins are a source of bioactive peptides. Recent studies have indicated that protein-derived peptides released in buffalo cheese acid whey exert a cytomodulatory effect in human epithelial colon cancer (CaCo2) cells. The aim of the present study was to explain the molecular mechanism involved in the response of CaCo2 cells to oxidative stress in the presence of peptide fractions of buffalo cheese whey, purified and characterized by mass spectrometry.
We demonstrated that treatment of CaCo2 treated with H2O2 (H-CaCo2) cells with a partially purified peptide sub-fraction (f3) from buffalo cheese acid whey induced a reduction of mitochondrial superoxide anion with subsequent decrease in heat shock protein 70 and 90 expression. Moreover, we observed a 5-fold decrease in cyclin A expression and cell cycle arrest in G1/G0 phases. These responses were associated with increased activity of alkaline phosphatase and beta-galactosidase, markers of differentiation and senescence respectively.
The structural characterization of the active peptide fraction and the elucidation of the effects induced by its treatment on H-CaCo2 cells in vitro demonstrated an activity of this peptide sub-fraction in the modulation of cell cycle, thus suggesting potential application for the development of nutraceuticals as well as health-promoting functional foods.
牛奶蛋白是生物活性肽的来源。最近的研究表明，在水牛乳酸性乳清中释放的蛋白质衍生肽对人结肠上皮癌细胞（CaCo2）具有细胞调节作用。本研究的目的是解释在存在水牛乳清肽的情况下，CaCo2 细胞对氧化应激的反应的分子机制，这些肽通过质谱法进行了纯化和表征。
我们证明，用部分纯化的肽亚组分（f3）处理经 H2O2 处理的 CaCo2（H-CaCo2）细胞，可减少线粒体超氧阴离子，随后降低热休克蛋白 70 和 90 的表达。此外，我们观察到细胞周期蛋白 A 的表达减少了 5 倍，细胞周期停滞在 G1/G0 期。这些反应与碱性磷酸酶和β-半乳糖苷酶活性的增加有关，分别为分化和衰老的标志物。
活性肽部分的结构表征以及其对体外 H-CaCo2 细胞的处理所诱导的作用的阐明，证明了该肽亚部分在细胞周期调节中的活性，因此表明其在开发营养保健品以及促进健康的功能性食品方面具有潜在的应用。
