The molecular mechanisms by which dietary resistant
starches are believed to alter the development or progression
of colon cancer are incompletely understood. Potential mechanisms of action of dietary resistant starch on gene expression
and mutation, DNA methylation, histone modification, and
remodeling of chromatin are being studied intensively. Recently, animal studies identified both alterations in the microbiota and induction of protection against unrepaired DNA
damage by dietary high-amylose maize starch and butyrylated
high-amylose, with increased expression of genes involved in
repair of DNA (146), which, in rapidly dividing populations
of the colonic mucosa, is expected to result in fewer mutations
and reduced carcinogenesis. Butyrate has been also described
to exert an influence on cell proliferation and differentiation
through modulation of several signal transduction pathways
(147). In some colon cancer cell lines, constitutive expression
of the canonical Wnt pathway, an initiating event in most colorectal cancers, is upregulated by butyrate treatment, resulting
in a strong apoptotic response (148). Butyrate has also been
shown to influence gene expression in the colon by modulating RNA splicing (149).