The relationship between the structural characteristics of lactobacilli-EPS and its ability to induce apoptosis in colon cancer cells in vitro

Abstract

Colon cancer is one of the most common cancer around the world. Exopolysaccharides (EPSs) produced by lactobacilli as potential prebiotics have been found to have an anti-tumor effect. In this study, lyophilized EPSs of four Lactobacillus spp. for their impact on apoptosis in colon cancer cells (HT-29) was evaluated using flow cytometry. The relationship between capability of a lactobacilli-EPS to induce apoptosis and their monosaccharide composition, molecular weight (MW), and linkage type was investigated by HPLC, SEC, and NMR, respectively. Changes in apoptotic-markers were examined by qPCR and Western Blotting. EPSs were capable of inhibiting proliferation in a time-dependent manner and induced apoptosis via increasing the expression of Bax, Caspase 3 and 9 while decreasing Bcl-2 and Survivin. All EPSs contained mannose, glucose, and N-acetylglucosamine with different relative proportions. Some contained arabinose or fructose. MW ranged from 10 2 –10 4 Da with two or three fractions. EPS of L. delbrueckii ssp. bulgaricus B3 having the highest amount of mannose and the lowest amount of glucose, showed the highest apoptosis induction. In conclusion, lactobacilli-EPSs inhibit cell proliferation in HT-29 via apoptosis. Results suggest that a relationship exists between the ability of EPS to induce apoptosis and its mannose and glucose composition.

Characterization of lactic acid bacteria derived exopolysaccharides for use as a defined neuroprotective agent against amyloid beta1–42-induced apoptosis in SH-SY5Y cells

“…Mannose (88.25%), glucose (9.54%), sucrose+maltose (1.10%), fructose (1.04%), and n-acetyl glucosamine (0.07%) were determined in L. delbrueckii ssp. bulgaricus B3 and mannose (71.03%), glucose (25.97%), arabinose (2.73%), and n-acetyl glucosamine (0.27%) in L. plantarum GD2 in our previous study 32 . The presence of different sugar moieties suggests that the l-EPSs were heteropolysaccharides.…”

“…bulgaricus B3 was found to be 1.2 × 10 4 and 3.5 × 10 2 Da. The molecular weight of l-EPS from L. plantarum GD2 was found to be 2.4 × 10 3 and 2.3 × 10 2 Da in our previous study 32 . EPSs with low molecular weight (≤10 4 Da) can reportedly pass readily through the membranes of host cells 35 .…”

“…In this study the amount of N in l-EPSs by elemental analysis was 5.94 and 1.58%. According to the data we obtained from our previous study 32 (due to the presence of n-acetyl glucosamine in the monomer compositions of l-EPSs), N may be caused by n-acetyl glycosamine. Du et al 41 suggested that N originated from proteins or chitin.…”

“…According to these findings, all study lactobacilli produced l-EPSs with the same type of sugar bond, namely β-H1-H3 (β-D-Mannose-α-D-Mannose)/α-H1-H2 (α-D-Mannose-α-D-Glucose), which were named as β−1,3 (β-D-Mannose-α-D-Mannose) and α-1,2 (α-D-Mannose-α-D-Glucose), respectively. Also, α(1-2), and β(1-3) bonds were determined in the structure of l-EPSs in our previous study 32 . In a study by Tsai et al 38 polysaccharide-peptide complexes were detected in Cordyceps militaris (CPSPs) and showed a characteristic inhibitory action against acetylcholinesterase (AchE).…”

Postbiotic-Enabled Targeting of the Host-Microbiota-Pathogen Interface: Hints of Antibiotic Decline?

“…Not surprisingly, the host-GM axis may affect cancer genesis and development as well. Postbiotics have also shown antiproliferative activity against colon cancer cells, likely by controlling immune responses and through the activation of pro-apoptotic cell death pathways [235,236]. In particular, butyrate and propionate inhibited host's tumor cell HDACs by a mechanism that is still obscure.…”