Key Findings
In this research, the effect of flaxseed and its fiber on the expression of some genes that are involved in azoxymethane (AOM) induced colon cancer in Sprague Dawley rats were assessed. Flaxseed and its TNDF did not significantly decrease the total number of aberrant crypt foci (ACF), which are used to identify some modulators of colon carcinogenesis in animal models, flaxseed significantly decreased the crypt multiplicity. Modifications were reported in the expressions of genes involved in cell cycle arrest, proliferation and mitochondrial apoptosis. The authors suggest that the tumor suppression was induced by apoptosis and decreased cell proliferation. Further flaxseed and its fiber can induce the expression of genes involved in proliferation, cell cycle arrest, and mitochondrial apoptosis. These changes in gene expression might be influenced by the presence of dietary antioxidants associated with dietary fiber, particularly lignans and phenolic acids (mainly ferulic acid).
ABSTRACT
The influence of flaxseed (Linum usitatissimum L.) and its total non digestible fraction (TNDF) on the expression of genes involved in azoxymethane (AOM) induced colon cancer in Sprague Dawley rats was analyzed. The dose used in the animal model was two tablespoons of flaxseed per day, which is the dose recommended for humans. Flaxseed significantly decreased the crypt multiplicity (10.50 plus or minus 3.5) compared with the AOM treatment (34.00 plus or minus 11.0), which suggests that flaxseed exhibits a preventive effect against colon cancer. Both treatments (flaxseed and TNDF) influence the overexpression of genes involved in cell cycle arrest and mitochondrial apoptosis: p53, p21, bcl2, bax and caspase3. Flaxseed induced the expression of p53 and p21, whereas TNDF triggered the p21 independent expression of p53. This finding suggests that both of these treatments induced cell cycle arrest. In addition, TNDF induced mitochondrial apoptosis because the TNDF plus AOM group exhibited the expression of caspase3, decreased bcl2 expression and increased bax expression. These results suggest that the expression of the analyzed genes is associated with the presence of dietary antioxidants linked to the cell wall of flaxseed. (Authors abstract)
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