Inflammation and Cancer: Role of Tight Junctions

Tight junctions are critical for the homeostatic maintenance of epithelial barrier integrity, especially in the gastrointestinal tract. In addition, tight junction proteins serve as intermediary molecules in a variety of signaling pathways in both health and disease. Dysregulation of tight junction proteins as both a result of and secondary to infection, autoimmunity, or malignancy can either ameliorate or worsen disease, depending on the context. The intricacies of tissue-and pathology-specific contexts for barrier integrity and tight junction protein signal-ing are still poorly understood, but in this chapter, we will explore how tight junction proteins contribute to gut barrier integrity and how they are affected by inflammation during infection and gut dysbiosis and during inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis. Further, we will discuss the involvement of various tight junction proteins in major oncogenic signaling pathways and how their dysregulation in cancer promotes tumor proliferation, invasion, and metastasis.