Potential role of Escherichia coli DNA mismatch repair proteins in colon cancer.

The epithelium of gastrointestinal tract organizes many innate defense systems against microbial intruders such as integrity of epithelial, rapid eviction of infected cells, quick turnover of epithelial cell, intrinsic immune responses and autophagy. However, Enteropathogenic Escherichia coli (EPEC) are equipped with well developed infectious tricks that evade the host defense systems and utilize the gastrointestinal epithelium as a multiplicative foothold. During multiplication on and within the epithelium, EPEC secrete various toxins that can weaken, usurp, and use many host cellular systems. However, the possible mechanisms of pathogenesis are still poorly elusive. Recent study reveals the existence of EPEC in colorectal cancer patients and their potential role in depletion of DNA mismatch repair (MMR) proteins of host cell in colonic cell lines. The EPEC colonised intracellularly in colon mucosa of colorectal carcinoma whereas extracellular strain was detected in mucosa of normal colon cells. Interestingly, alteration in MutS, MutL complexes and MUTYH of mammalian cells may be involved in development of CRC. These data propose that MMR of E. coli may be potential therapeutic targets and early detection biomarkers for CRC. This article reviews the potential role of E. coli MutS, MutL and MutY protein in CRC aetiology.