Butyrate Induces Glutathione S-Transferase in Human Colon Cells and Protects From Genetic Damage by 4-Hydroxy-2-Nonenal

Abstract

Butyrate, one of the major products of gut fermentation, is known to inhibit proliferation, induce apoptosis and differentiation, and increase phase II enzyme activities in tumor cells, whereas little information is available on protective effects in less-transformed colon cells. The aim of this study was to investigate whether the chemoprotective mechanism of glutathione S-transferase (GST) induction by butyrate could also play a role in earlier stages of colon carcinogenesis and whether chemoresistance of cells toward the endogenous genotoxic risk factor 4-hydroxy-2-nonenal (HNE) could be a consequence of butyrate treatment. As cell models, we used the human tumor cell lines HT29 and HT29 clone 19A, a differentiated subclone with properties resembling primary colon cells. We determined the expression of GSTP1 protein (enzyme-linked immunosorbent assay), the major GST in HT29, GSTP1 mRNA (Northern blotting), GST activity, intracellular glutathione, and total protein. The genotoxic impact of HNE (100-200 microM) was compared in butyrate-treated and nontreated cells using single-cell microgel electrophoresis. Our results show that GSTP1 mRNA, GSTP1 protein, GST activity, and total protein were increased (1.2- to 2.5-fold) and glutathione levels were maintained after 24-72 h of incubation with 4 mM butyrate. Moreover, a marked reduction of HNE-induced genotoxicity was caused by preincubation with butyrate. Butyrate also induced the phosphorylation of extracellular signal-regulated kinases (ERK1/2, Western blotting) after 5-30 min, which indicates a regulation of GST expression by this signal pathway. Most effects were greater in HT29 parent cells than in clone cells. In conclusion, butyrate enhances expression of GST and other proteins in both cell lines, which leads to an enhanced chemoprotection, reducing the impact of HNE genotoxicity. Thus butyrate could play a role in early and later stages of cancer prevention by reducing exposure to relevant risk factors.

Chemopreventive potential of in vitro fermented nuts in LT97 colon adenoma and primary epithelial colon cells

“…Former studies indicated that the induction of these genes can be attributed to butyrate as the key fermentation product of dietary fiber. 28,35,41,42 Though there is no direct link between the daily recommended nut intake and FS used in the present study, we could recently confirm that the fermentation of nuts results in up to 2.8-fold higher concentrations of short chain fatty acids compared to the control and a shift of molar ratios towards butyrate production ranging in physiological observed FIGURE 3 Growth inhibiting of LT97 colon adenoma cells after incubation with fermented nut samples and controls (blank, Synergy1®) in concentrations of 2.5-20% for 24 h (a), 48 h (b), and 72 h (c) (mean + SD, n = 3). Significant differences between blank and fermentation supernatants (FS) of Synergy1® or nuts (***P ≤ 0.001, **P ≤ 0.01, *P ≤ 0.05) and between FS ( a-e P ≤ 0.05, equal letters represent significant differences) were obtained by two-way Anova/Bonferroni post-test.…”

Glutathione level regulates HNE-induced genotoxicity in human erythroleukemia cells

“…This phenomenon can lead to gene alterations causing potential tumor formation or carcinogenesis, and other pathological conditions. Increased cellular GSH is known to protect the cells from HNE-induced cytotoxicity and DNA damage (Nakajima et al, 2002;Cao et al, 2003;Ebert et al, 2001). Under oxidative stress GSH is oxidized to GSSG, which is transported out (Srivastava and Beutler, 1969;Meister et al, 1986) resulting in a significant decrease in cellular GSH levels.…”

Glutathione S‐transferase theta 1 protects against colitis through goblet cell differentiation via interleukin‐22

“…Interestingly, GSTs are reportedly enhanced by products of gut fermentation in animals or butyrate in human colon tumor cell lines. 6 Of the members of GSTs, glutathione S-transferase theta 1 (GSTT1), and GSTM1 in particular have become a recent target of active investigation into their role in increased susceptibility to IBD, Behçet's disease (BD), or other autoimmune diseases such as primary sclerosing cholangitis when either of the two GSTTs lose their function. 2,7,8 Deletion of the GSTT1 gene, a 50 kb genomic sequence containing the entire gene located on chromosome 22q11.2, results in a GSTT1-null genotype, 5,9 fails protein synthesis, and can decrease the ability to detoxify damaging compounds.…”