Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 54 6 2025 06 02 1310 1319 EN Marjan Ghiyasvand Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran Ardeshir hesampour Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran Hossein Dabiri Department of Microbiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Javad Arasteh Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran 2024 10 15 2025 01 14 Background: Colorectal cancer is one of the deadliest cancers with poor prognosis and limited treatment options. Microbiota and their metabolites, including toxins, have been shown to possess anti-tumor properties. Outer membrane vesicles (OMVs) from Escherichia coli may trigger inflammation in intestinal cells. We aimed to explore the anti-cancer effects of E. coli-derived OMVs on colorectal cancer cells by promoting apoptosis and pyroptosis, particularly through the over-expression of GSDMD in the CT-26 cell line. Methods: In 2022, five non-replicating probiotic strains of E. coli were obtained from the Histogenotech Company in Tehran, and their OMVs were isolated and characterized. The CT-26 cell line was used to assess cell toxicity and the apoptotic effects of E. coli-derived OMVs. Real-time PCR and western blotting were performed to measure the expression of apoptosis and pyroptosis markers (GSDMD, NLRP3, and ROCK). Results: The E. coli strains produced nanovesicles (5-200 nm in diameter). OMVs significantly reduced the viability of CT-26 cells and induced apoptosis at a concentration of 10 µg. The expression of GSDMD and NLRP3 was increased, while ROCK expression was downregulated in treated colorectal cells. Conclusion: E. coli-derived OMVs can trigger inflammatory processes and induce negative effects on colorectal cancer cells. Further research is needed to evaluate their potential for colorectal cancer treatment.      Keywords: E. coli; ; r; Apoptosis; Inflammation   https://ijph.tums.ac.ir/index.php/ijph/article/view/36927 https://ijph.tums.ac.ir/index.php/ijph/article/download/36927/8583