Proteinaceous Postbiotic Metabolite Produced by Lactobacillus plantarum I-UL4 Exhibits Anti-colorectal cancer and Immunomodulatory Properties in Azoxymethane-induced Rats:

This study determined the anti-cancer properties of proteinaceous postbiotic metabolite (PPM) produced by Lactobacillus plantarum I-UL4, against colorectal cancer model in rats and elucidated the immunomodulatory activities involved. The rats were subjected to injection with azoxymethane for two subsequent weeks to induce colorectal cancer, and subsequently fed with PPM (0.25%, 0.5% and 0.75% (w/v)) added into drinking water, at week 26, once daily for 12 weeks. Cancer severity and immunomodulatory properties of PPM were determined by histopathology analysis and level of cytokines (IFN-γ, TNF-α, IL-12 and IL-5) in serum, spleen and thymus cell suspensions, respectively. Treatment with PPM significantly (p<0.05) reduced the total number of aberrant crypt foci (ACF) and crypt multiplicity, incidence of tumor, adenoma and adenocarcinoma, with decreased expression of s-catenin in a dose-independent manner. The level of all cytokines, except for IL-12 in serum, increased significantly (p<0.05) in both spleen and thymus cell suspensions after treatment with PPM compared to control. PPM produced by Lactobacillus plantarum I-UL4 exhibited anti-colorectal cancer properties and enhanced the level of several cytokines that play crucial roles in the inhibition of colon carcinogenesis.