Zeitschrift für Bioanalyse und Biomedizin

Identification of Lactobacillus Fermentum Strains with Potential against Colorectal Cancer by Characterizing Short Chain Fatty Acids Production, Anti-Proliferative Activity and Survival in an Intestinal Fluid: In Vitro Analysis

Abstract

Imen Kahouli, Meenakshi Malhotra, Catherine Tomaro-Duchesneau, Laëtitia Sonia Rodes, Moulay A. Alaoui-Jamali and Satya Prakash

The use of probiotics as preventive agents in colorectal cancer (CRC), as widely suggested in many clinical and pre-clinical studies, was often linked to the potency of short chain fatty acids (SCFAs) in the gut. However, there remains an incomplete understanding of the fatty-acid-producing activity of certain probiotics and their cancer preventive potential. In the current study, L. fermentum strains were investigated for their potential use with CRC treatments. Using cell-free extracts, L. fermentum NCIMB -5221, - 2797, and -8829 were first compared based on their SCFAs production and anti-proliferative activity against Caco-2 colon cancer cells. The corresponding SCFAs synthetic formulations, similar to the ones produced by the bacteria, were prepared and compared with the latter to determine the role and efficacy of naturally produced SCFAs in inhibiting the proliferation of colon cancer cells. Subsequently, the bioactivity and stability of L. fermentum bacterial strains in a simulated intestinal fluid (SIF) was determined. Results showed that L. fermentum NCIMB -5221 and -8829 were the most potent in producing SCFAs, in particular, acetic (192.3 ± 4 mg/L minimum), propionic (69.2 ± 1.6 mg/L minimum), and butyric (35.4 ± 2.9 mg/L minimum) acids. They were also found to inhibit the growth of Caco-2 cells (53.4 ± 1.6%, 72 h, p = 0.021) in comparison with L. acidophilus ATCC 314. Additionally, they showed resistance to SIF (16.3 ± 1.9% minimum, 72 h, p = 0.006) and produced SCFAs in SIF at concentrations high enough to significantly inhibit Caco-2 proliferation (74.73 ± 2.1%, 72 h). Based on characteristics related to bacterial cell survival, SCFA production, and anti-proliferative activity, L. fermentum NCIMB -5221 and - 2797 could potentially be considered as biotherapeutic agents against CRC.