Inhibition of colon cancer cell proliferation and genotoxicity of 4-nitroquinoline-N-oxide on human intestine cell by several probiotics and fermented milk
Date Issued
2008
Date
2008
Author(s)
Chu, Fang-jung
Abstract
Colorectal cancer is a major cause of death from cancer in Taiwan. Approximately 70 % of colorectal cancer is related to dietary habit. Many researches showed that probiotics, both cellular compositions and fermented products have antimutagenic and antitumor activities on mutagens. In present study, we used several probiotics, which have been studied in our laboratory for their acid-resistance, bile salt tolerance, and antimutagenicity against B[a]P, t-BOOH, and H2O2. In addition, MTT assay was used to explore the effects of several probiotics against 4NQO cytotoxicity on Int-407 and the proliferation of human colon cancer cell HT-29 and Caco-2. Furthermore, possible antimutagenic mechanisms of probiotics were investigated by section-preincubation test and comet assay to explore the effects of several probiotics against 4NQO-induced DNA damage on Int-407. The results showed that a high probiotics population inhibits colon cancer cell more effectively than a low probiotics population. Among the strains, the crude cell walls of Bifidobacterium lactis Bb-12 exhibited the most potent inhibition activity in HT-29 and Caco-2 for 48h and the viability were 70.6 % and 63.3 %, respectively. The heat-killed cells of B. lactis Bb-12 and L. casei 01 significantly reduced the genotoxicity of 4NQO-induced DNA damage on Int-407 (p < 0.05). In addition, the crude cell walls and intracellular extracts of probiotics showed inhibitory effects against 4NQO cytotoxicity. The primary mechanism of crude cell walls was desmutagenic effect and intracellular extracts was blocking effect. Besides, fermented milk with B. lactis Bb-12 and L. casei 01 also had inhibition on 4NQO-induced DNA damage and cytotoxicity on Int-407. Their main mechanisms were the same as above, inhibition rate were 37.4 % - 52.5 % and 34.1 % - 41.4 %, respectively.
Subjects
probiotics
comet assay
desmutagenic effect
blocking effect
SDGs
Type
thesis
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