Differential antineoplastic effects of butyrate in cells with and without a functioning DNA mismatch repair

Area of Science:

• Oncology
• Molecular Biology
• Epigenetics

Background:

• Mismatch repair deficiency is common in colon cancer.
• Butyrate, a short-chain fatty acid, has shown potential anti-cancer properties.
• The role of MLH1 gene status in butyrate's effects is not fully understood.

Purpose of the Study:

• To investigate the differential anti-cancer effects of butyrate on colon cancer cells based on MLH1 gene status.
• To elucidate the molecular mechanisms, including epigenetic modifications and gene expression changes, underlying these differential effects.

Main Methods:

• SW48 colon cancer cells with silenced MLH1 (due to hypermethylation) and demethylated SW48 cells with reexpressed MLH1 were treated with butyrate.
• Assessed effects on viable cell number, MLH1 promoter methylation, and expression of cell cycle genes CDK4 and GADD45A.

Main Results:

• Butyrate suppressed viable cell number and reduced MLH1 promoter methylation in MLH1-silenced cells.
• In contrast, butyrate increased viable cells and MLH1 promoter methylation in MLH1-reexpressed cells.
• Butyrate differentially regulated CDK4 and GADD45A expression, with greater effects observed in MLH1-reexpressed cells.

Conclusions:

• Butyrate exhibits more potent anti-neoplastic effects on colon cancer cells with MLH1 dysfunction.
• Differential expression of cell cycle regulatory genes (CDK4, GADD45A) contributes to the observed effects.
• Epigenetic modulation of the MLH1 gene promoter by butyrate plays a role in its anti-cancer activity.