The Effects of Short-Chain Fatty Acids on Human Colon Cancer Cell Phenotype Are Associated with Histone Hyperacetylation

Abstract

The short-chain fatty acid (SCFA) butyrate is produced via anaerobic bacterial fermentation within the colon and is thought to be protective in regard to colon carcinogenesis. Although butyrate (C4) is considered the most potent of the SCFA, a variety of other SCFA also exist in the colonic lumen. Butyrate is thought to exert its cellular effects through the induction of histone hyperacetylation. We sought to determine the effects of a variety of the SCFA on colon carcinoma cell growth, differentiation and apoptosis. HT-29 or HCT-116 (wild-type and p21-deleted) cells were treated with physiologically relevant concentrations of various SCFA, and histone acetylation state was assayed by acid-urea-triton-X gel electrophoresis and immunoblotting. Growth and apoptotic effects were studied by flow cytometry, and differentiation effects were assessed using transient transfections and Northern blotting. Propionate (C3) and valerate (C5) caused growth arrest and differentiation in human colon carcinoma cells. The magnitude of their effects was associated with a lesser degree of histone hyperacetylation compared with butyrate. Acetate (C2) and caproate (C6), in contrast, did not cause histone hyperacetylation and also had no appreciable effects on cell growth or differentiation. SCFA-induced transactivation of the differentiation marker gene, intestinal alkaline phosphatase (IAP), was blocked by histone deacetylase (HDAC), further supporting the critical link between SCFA and histones. Butyrate also significantly increased apoptosis, whereas the other SCFA studied did not. The growth arrest induced by the SCFA was characterized by an increase in the expression of the p21 cell-cycle inhibitor and down-regulation of cyclin B1 (CB1). In p21-deleted HCT-116 colon cancer cells, the SCFA did not alter the rate of proliferation. These data suggest that the antiproliferative, apoptotic and differentiating properties of the various SCFA are linked to the degree of induced histone hyperacetylation. Furthermore, SCFA-mediated growth arrest in colon carcinoma cells requires the p21 gene.

Histone deacetylase inhibitor- and PMA-induced upregulation of PMCA4b enhances Ca2+ clearance from MCF-7 breast cancer cells

“…2B) shows that at a lower concentration of valerate (2 mM) growth inhibition was less pronounced and significant cell death could be detected only after longer incubation times. Therefore, in further experiments we treated cells with valerate instead of butyrate or phenylbutyrate because it resulted in more viable cells as it was shown previously [23,24]. The proliferation of PMA treated cells was also diminished, however, no significant decrease of viability was observed during the 4 day treatment suggesting that in accordance with previous reports, PMA inhibited growth but did not cause significant cell death [44].…”

“…SCFAs such as butyrate and its aryl-substituted analog phenylbutyrate are known differentiating agents in several experimental systems [20][21][22][23][24]. Moreover, they have been shown to enhance PMCA4b expression in colon cancer cells [25,26].…”

“…Expression of PMCA 2, 3 and 4 isoforms were 4 enhanced during differentiation of the neuroblastoma cell line IMR-32, and this resulted in increased Ca 2+ efflux [16]. Short chain fatty acids (SCFAs) are histone deacetylase inhibitors that can inhibit proliferation of tumor cells, induce differentiation and apoptosis [17][18][19][20][21][22][23][24].…”

Knockdown of peroxisome proliferator-activated receptor-β induces less differentiation and enhances cell–fibronectin adhesion of colon cancer cells

“…It has been shown that less-differentiated colon cancers, compared with more-differentiated ones, assume a more malignant morphology, as represented by obvious polymorphism with more irregular nuclei, and show higher abilities of proliferation and colony formation, coupled with less CEA secretion (Bordonaro et al, 2002;Hinnebusch et al, 2002;Park et al, 2005). Thus, the finding that PPAR-b knockdown caused more malignant morphology, larger colonies and less CEA production in KM12C, KM12SM and KM12L4a cells shows that PPAR-b knockdown induces less differentiation of both poorly and highly metastatic colon cancer cells, indicating that PPAR-b facilitates the differentiation of colon cancer.…”

Influence of miRNA-106b and miRNA-135a on butyrate-regulated expression of p21 and Cyclin D2 in human colon adenoma cells

“…Butyrate is an energy source for normal colon epithelial cells. In contrast, it could be shown that butyrate functions as histone deacetylase inhibitor (HDI), inhibits proliferation and induces apoptosis and differentiation in colon cancer cells mediated, e.g., by induction of p21 gene expression (Borowicki et al 2010;Hinnebusch et al 2002). There is evidence from two studies that these chemopreventive effects of butyrate are mediated also by miRNAs since butyrate as HDI also regulates miRNA expression profiles in colon cancer cells (Hu et al 2011;Humphreys et al 2013).…”