• Evaluation of anticancer effects of postbiotics derived from Enterococcus faecium strain KCH-1 on HT29 colon cancer cell line
  • Negar Shafiei,1 Masoud Javanmardi,2 Sepideh Khaleghi,3,*
    1. Department of Biotechnology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
    2. Department of Medical Biotechnology, Applied Biophotonics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran
    3. Department of Biotechnology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran


  • Introduction: Colorectal cancer (CRC) is a prevalent and life-threatening malignancy closely linked to the intestinal epithelium and gut microbiome. Recent advancements in research have highlighted postbiotics—defined as non-viable microbial cells or their components that confer health benefits—as a safer and more stable alternative to probiotics. This study aims to investigate the anti-cancer potential of postbiotics derived from Enterococcus faecium strain KCH-1, specifically focusing on their effects on HT29 human colon cancer cell lines. The findings demonstrate that postbiotic components, including cell-free supernatants and exopolysaccharides, significantly inhibit cancer cell proliferation, induce apoptosis, and enhance oxidative stress. These results suggest that postbiotics could serve as effective agents in CRC treatment by modulating immune responses and interfering with tumor cell growth. This research contributes to the growing body of evidence supporting postbiotics as a novel therapeutic strategy in oncology, offering a promising approach to complement traditional cancer therapies.
  • Methods: This study details the methodologies employed to evaluate the anti-cancer effects of postbiotics derived from Enterococcus faecium strain KCH-1 on HT29 colon cancer cells. Microbial cultures were initiated by preparing solid and liquid MRS media, followed by inoculation with bacterial strains revived from frozen storage. A microbial suspension was cultivated at 37°C, with subsequent centrifugation to separate bacterial cells from the supernatant, which was then processed for lyophilization to produce postbiotics. The HT29 colon cancer cell line was acquired and cultured in DMEM supplemented with 10% FBS and antibiotics For experimental assays, cell viability and cytotoxicity were assessed using the MTT assay, while the effects of postbiotics on cell apoptosis and cell cycle progression were analyzed through flow cytometry, utilizing staining methods with Annexin V-FITC/PI and propidium iodide (PI). Additionally, reactive oxygen species (ROS) levels were evaluated to determine oxidative stress effects. This comprehensive methodological approach facilitates the exploration of postbiotic applications in cancer therapy, providing insights into their potential mechanisms of action.
  • Results: The results of this study demonstrate the significant anti-cancer effects of postbiotics derived from Enterococcus faecium strain KCH-1 on HT29 colon cancer cells. The MTT assay revealed that varying concentrations of postbiotics (1000, 500, 250, 125, and 62.5 µg/ml) resulted in a marked reduction in cell viability over 24, 48, and 72 hours, with an IC50 value of 1000 µg/ml corresponding to 51.42% cell survival at 48 hours. Flow cytometric analysis indicated a notable increase in early apoptosis (21.6%) in treated cells compared to the control, where the proportion of viable cells decreased to 76.4%. Furthermore, treatment with postbiotics significantly affected cell cycle progression, leading to an increase in cells arrested in the S phase (40.92%), indicating that postbiotics promote apoptosis and disrupt normal cell division. Additionally, the assessment of reactive oxygen species (ROS) levels showed that postbiotic treatment led to a substantial reduction in macrophage migration inhibitory factor (MIF) levels, suggesting an increase in oxidative stress and contributing to the observed cytotoxic effects. Overall, these findings underscore the potential of Enterococcus faecium derived postbiotics as effective agents in the treatment of colorectal cancer by inducing apoptosis and enhancing oxidative stress within cancer cells.
  • Conclusion: The study highlights the promising anti-cancer effects of postbiotics derived from Enterococcus faecium on HT29 colon cancer cells. Findings demonstrate that these postbiotics significantly inhibit cell viability and promote apoptosis in a dose-dependent manner. The MTT assay confirmed that increasing concentrations of postbiotics lead to decreased cell survival, with a notable IC50 value of 1000 µg/ml resulting in 52.24% cell viability at 48 hours. Flow cytometric analysis revealed increased early apoptosis and cell cycle arrest, particularly in the S phase, indicating a disruption in cellular proliferation. Furthermore, elevated levels of reactive oxygen species (ROS) were observed, suggesting that postbiotics induce oxidative stress, which may contribute to their cytotoxic effects. Overall, these results underscore the potential of Enterococcus faecium-derived postbiotics as a novel therapeutic strategy for colorectal cancer treatment, emphasizing their ability to enhance apoptotic pathways and generate oxidative stress in cancer cells. This research supports the exploration of postbiotics as adjunctive therapies in oncology, offering a safe and effective alternative to conventional cancer treatments.
  • Keywords: Probiotic , postbiotic , colon cancer