| Summary: | 碩士 === 中國醫藥大學 === 營養學系碩士班 === 100 === Breast cancer is the most leading incidence and the 4th causes of death from female cancers in Taiwan. In recent years, it’s mortality rate and average age of death are obviously increase and get more and more younger. Although there are multiple strategies for breast cancer treatment, recurrence and side effect would still occur and destroy patient’s normal daily life, thus new treatment strategies are in great need for cancer patients.
There are some reports describing that bioactive peptides possess anti-cancer property, and fish protein hydrolysates induce the anti-proliferative activity in human breast cancer cell lines. However, the study did not determine the amino acid sequence of the peptides. Therefore, the knowledge of the anticancer activity of protein hydrolysates is limited, and the detail information (such as the amino acid sequence and molecular weight) need further researches to be determined.
The aim of this study was to investigate the anti-cancer potential and mechanism of protein hydrolysates derived from tuna cooking juice against human breast cancer cell. These protein hydrolysates hydrolyzed by Protease XXIII (PA) and Orientase 90N (OR) for different hours.
The results showed that the most anti-proliferation sample (PAH) was tuna cooking juice hydrolyzed by PA for 1 hour and its molecular weight was over 2500 Dalton fractionated by ultrafiltration. We found that PAH could strongly inhibit cell viability of MCF-7 in a dose-dependent manner without affecting normal breast epithelial cells (MCF-10A) , and its possessed about 38% anti-proliferation at the concentration of 1mg/mL after incubation for 72 hours. Flow cytometry indicated that MCF-7 treated with PAH caused apoptosis and cell cycle arrest by increased the cell population in S-phase and simultaneously decreasing the G1 and G2/M populations. Moreover, western blot assay suggested that PAH treatment induced S phase arrest and apoptosis associated with decrease in the protein expression of cyclin A, Bcl-2, PARP and caspase 9 but increase p21, Bax and cleaved caspase 3 expression. In vitro simulated gastrointestinal digestion showed that PAH may be hydrolyzed by digestive enzyme and the anti-proliferative activities could be decreased.
These results show that PAH modulates signal transduction pathways for inhibition of breast cancer cell growth and can be used as a dietary supplement for prevention of breast cancer.
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