Increased Risk of Invasive Colon Carcinomas Linked to IBD in ATF6-Driven Mouse Model

Overview

This study demonstrates that interleukin-10 deficiency in mice expressing activated ATF6 in intestinal epithelial cells significantly increases susceptibility to colitis-associated cancer (CAC), with 77% developing colonic adenomas and invasive carcinomas. Tumorigenesis was microbiota-dependent and correlated with mucosal immune infiltration and dysbiosis, highlighting the role of chronic inflammation and microbiota in ATF6-driven colon cancer.

Background

Inflammatory bowel diseases (IBD) such as Crohn’s disease and ulcerative colitis are associated with chronic intestinal inflammation, which increases the risk of colitis-associated cancer (CAC). The unfolded protein response (UPR) pathway, particularly activating transcription factor 6 (ATF6), has been implicated in spontaneous colorectal tumorigenesis in mice. IL-10 is an anti-inflammatory cytokine that modulates immune responses and its deficiency promotes inflammation. This study investigates how IL-10 deficiency influences ATF6-driven tumorigenesis in a novel mouse model, emphasizing the interplay between ER stress, inflammation, and microbiota in colon cancer development.

Data Highlights

Key Findings

• IL-10 deficiency in nATF6IEC mice markedly increases susceptibility to colonic adenomas and invasive carcinomas, with 77% tumor incidence at 12 weeks.
• Tumor formation is associated with mucosal immune cell infiltration, predominantly CD11b+ granulocytes and monocytes.
• Microbiota dysbiosis at the mucosal surface correlates with tumor development; germ-free conditions reduce tumor incidence.
• Colonization of germ-free nATF6IEC;Il10-/- mice with IBD patient stool or minimal biosynthetic microbial consortia re-establishes tumorigenesis, confirming microbiota dependence.
• Increased ATF6 expression is observed in IBD patients during active disease, supporting translational relevance.
• IL-10 normally inhibits inflammation-induced ATF6 recruitment to the Grp78 promoter, linking immune regulation to ER stress pathways in tumorigenesis.

Clinical Implications

These findings underscore the importance of controlling chronic inflammation and modulating microbiota composition in IBD patients to reduce the risk of colitis-associated colon cancer. Targeting the ATF6 pathway or restoring IL-10 function may represent potential therapeutic strategies to prevent or mitigate tumor development in this high-risk population. Additionally, mucosal microbiota profiling may provide better predictive value for early tumorigenic changes than stool analysis alone.

Conclusion

IL-10 deficiency exacerbates ATF6-driven colon tumorigenesis in a microbiota-dependent manner, highlighting a critical interaction between ER stress signaling, immune regulation, and microbial factors in colitis-associated cancer. This novel mouse model provides valuable insights into mechanisms underlying IBD-related cancer risk and potential intervention points.

References

1. Original Article -- Increased Risk of Invasive Carcinomas Linked to Inflammatory Bowel Disease in a Mouse Model of ATF6-Driven Colon Cancer