BIFCOLC-QS · Quorum sensing as a tool to detect and target pro-oncogenic microbial biofilms associated with right-sided colorectal cancer

Colorectal cancer (CRC) development and progression have been linked to the presence of pro-oncogenic bacterial strains in the intestine, such as Fusobacterium nucleatum, pks+ Escherichia coli and enterotoxigenic Bacteroides fragilis. These pathogenic bacteria produce toxins that can disrupt gut epithelial integrity resulting in heightened pro-inflammatory response, enhanced DNA mutations, and increased cell proliferation, which can eventually lead to adenoma formation. In addition, these bacterial pathogens show increased genotoxicity by forming invasive polymicrobial biofilms, thereby resulting in CRC development. Recently it has been reported that anatomical location plays a crucial role in CRC development, progression, microbial colonization, response to therapies and disease outcome. Indeed, right-sided CRC is generally associated with pro-oncogenic bacterial biofilms and is known to have an overall worse prognosis compared to left-sided CRC. Pathogenic bacteria use quorum sensing (QS) machinery in the gut for their communication, which is essential for biofilm formation. We aim to develop an intervention strategy employing QS machinery to engineer a probiotic bacterial strain with sensing and killing properties to detect and target these pro-oncogenic polymicrobial biofilms. The sensor device will detect autoinducers produced by pathogenic bacteria on encountering their biofilms, activating the killing device. The killing device expresses a biofilm degrading enzyme, Dispersin B, which will disrupt these biofilms and eventually kill the pathogenic bacteria residing in these biofilms by the type VI secretion system. These polymicrobial biofilms can act as a marker of CRC and help to understand the role of CRC-associated pathogenic bacteria in CRC development, which can eventually serve as a basis for developing future strategies for the diagnosis and treatment of CRC and other intestinal disorders associated with biofilms formed by pathogenic bacteria.