Butyrate may enhance toxicological defence in primary, adenoma and tumor human colon cells by favourably modulating expression of glutathione S -transferases genes, an approach in nutrigenomics

Abstract

Butyrate, formed by bacterial fermentation of plant foods, has been suggested to reduce colon cancer risks by suppressing the proliferation of tumor cells. In addition, butyrate has been shown to induce glutathione S-transferases (GSTs) in tumor cell lines, which may contribute to the detoxification of dietary carcinogens. We hypothesize that butyrate also affects biotransformation in non-transformed colon cells. Thus, we have investigated the gene expression of drug metabolism genes in primary human colon tissue, premalignant LT97 adenoma and HT29 tumor cells cultured in an appropriate medium+/-butyrate. A total of 96 drug metabolism genes (including 12 GSTs) spotted on cDNA macroarrays (Superarray; n = 3) were hybridized with biotin-labeled cDNA probes. To validate the expression detected with Superarray, samples of LT97 cells were also analyzed with high density microarrays (Affymetrix U133A), which include biotransformation genes that overlap with the set of genes represented on the Superarray. Relative expression levels were compared across colon samples and for each colon sample+/-butyrate. Compared with fresh tissue, 13 genes were downregulated in primary cells cultivated ex vivo, whereas 8 genes were upregulated. Several genes were less expressed in LT97 (40 genes) or in HT29 (41 and 17 genes, grown for 72 and 48 h, respectively) compared with primary colon tissue. Butyrate induced GSTP1, GSTM2, and GSTA4 in HT29 as previously confirmed by other methods (northern blot/qPCR). We detected an upregulation of GSTs (GSTA2, GSTT2) that are known to be involved in the defence against oxidative stress in primary cells upon incubation with butyrate. The changes in expression detected in LT97 by Superarray and Affymetrix were similar, confirming the validity of the results. We conclude that low GST expression levels were favourably altered by butyrate. An induction of the toxicological defence system possibly contributes to reported chemopreventive properties of butyrate, a product of dietary fibre fermentation in the gut.

Impact of butyrate on PKM2 and HSP90β expression in human colon tissues of different transformation stages: a comparison of gene and protein data

“…Among the most abundant SCFA, butyrate represents about 20% and reaches absolute concentrations of 11-25 mM in human feces, whereas concentrations in peripheral venous blood are even lower (Hamer et al 2008;Wolever and Chiasson 2000). Compared to acetate or propionate, the C 4 carbonic acid is best characterized and linked to numerous anti-cancer effects in vitro and in vivo, e.g., induction of apoptosis, inhibition of proliferation, and modulation of various gene families (Borowicki et al 2011;Pool-Zobel et al 2005;Zhang et al 2010). Therefore, the present study focused on butyrate and its impact on gene expression of HSP90b and PKM2 as well as their analog proteins in malignant and non-malignant (normal and adenoma) colon tissues derived from individual donors.…”

Influence of roasting on the chemopreventive potential of macadamia nuts

“…Butyrate, one of the main end products of dietary fiber fermentation in the colon, has been extensively studied as an agent with such suppressing activity on colon adenoma or carcinoma cells [13][14][15][24][25][26]. The formation of butyrate and other short-chain fatty acids was also identified recently in FS obtained from nuts including macadamia nuts [27].…”

Apple polyphenols modulate expression of selected genes related to toxicological defence and stress response in human colon adenoma cells

“…The LT97 cell line was cultured as previously described, 19 but instead of 2.5 U/ml PenStrep, 10 mg/ml Gentamicin (Invitrogen GmbH, Karlsruhe, Germany) was used. The cells between passages 21 and 32 were used for the experiments described here.…”

“…It was commercially produced (Miltenyi Biotec, K€ oln, Germany) according to our selection of the genes that was based on (i) functionality of the gene products in chemoprevention or carcinogenesis and (ii) expression levels in the numerous cell systems used in our laboratory. The baseline expression levels had previously been determined with Superarray membranes in several types human colon, 19 breast 20 and prostate 21 cells, and it was the aim of this study to assess the modulation of their expression in LT97 cells treated with AE.…”