The immunomodulatory effects of Candida albicans isolated from the normal gastrointestinal microbiome of the elderly on colorectal cancer.

The association of gut microbiota with occurrence and development of colorectal cancer (CRC) has been reported in recent studies. Probiotics have been shown to mediate anti-cancer effects through immune system. The aim of this study was to evaluate the efficacy of Lactobacillus plantarum and Candida albicans in the suppression of azoxymethane-induced CRC in male Fischer 344 rats. 30 adult male Fischer 344 rats were divided into 6 distinct groups (n = 5 per group): non-treated animals, fat-food intake group, fat-food and carcinogen intake group, CRC cancer-induced rats treated with the chemotherapy drug, CRC-induced rats treated with Lactobacillus plantarum, and CRC-induced rats treated with Candida albicans. Identification of Candida albicans isolated from human feces was performed by microbiological, biochemical, and PCR methods. The serum levels of IFN-γ, IL-4, TGF-β, and TNF-α were measured by ELISA. Pathological studies were performed through hematoxylin and eosin (H&E) staining method. The data were analyzed using one-way ANOVA and Tukey's post-hoc analysis. Shrinking cancer cells with very dark nuclei were observed in CRC-induced rats treated with the chemotherapy drug, Lactobacillus plantarum, and Candida albicans indicating the occurrence of apoptosis. Serum levels of IFN-γ, IL-4, and TGF-β significantly decreased compared to the control group (p < 0.05). Lactobacillus plantarum and Candida albicans isolated from the gastrointestinal tract of the elderly and healthy individuals can efficiently improve CRC.