Myosin light chain kinase expression induced via tumor necrosis factor receptor 2 signaling in the epithelial cells regulates the development of colitis-associated carcinogenesis

• Published in: PloS one 2014-02, Vol.9 (2), p.e88369
• Main Authors: Suzuki, Masahiro, Nagaishi, Takashi, Yamazaki, Motomi, Onizawa, Michio, Watabe, Taro, Sakamaki, Yuriko, Ichinose, Shizuko, Totsuka, Mamoru, Oshima, Shigeru, Okamoto, Ryuichi, Shimonaka, Motoyuki, Yagita, Hideo, Nakamura, Tetsuya, Watanabe, Mamoru
• Format: Article
• Language: English
• Subjects: Activation; Animals; Biology; Carcinogenesis; Carcinogenesis - drug effects; Carcinogenesis - metabolism; Carcinogenesis - pathology; Carcinogens; Cell Line; Cell Proliferation - drug effects; Chains; Colitis; Colitis - metabolism; Colitis - pathology; Colon - drug effects; Colon - pathology; Colon - ultrastructure; Cytokines; Cytokines - secretion; Disease Models, Animal; Epithelial cells; Epithelial Cells - enzymology; Epithelial Cells - metabolism; Epithelial Cells - pathology; Epithelial Cells - ultrastructure; Female; Gastrointestinal diseases; Inflammation - pathology; Inflammation Mediators - metabolism; Inflammatory bowel disease; Inflammatory bowel diseases; Interferon-gamma - pharmacology; Interleukin 6; Intestinal Mucosa - drug effects; Intestinal Mucosa - pathology; Intestine; Kinases; Lamina propria; Medicine; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Muscle proteins; Myosin; Myosin-light-chain kinase; Myosin-Light-Chain Kinase - metabolism; Necrosis; NF-κB protein; Permeability; Receptors, Tumor Necrosis Factor, Type II - metabolism; Restoration; Rodents; Science; Signal Transduction - drug effects; Signaling; Tight Junctions - drug effects; Tight Junctions - metabolism; Tissues; Tumor necrosis factor; Tumor necrosis factor receptor 2; Tumor necrosis factor receptors; Tumor Necrosis Factor-alpha - pharmacology; Tumor necrosis factor-TNF; Tumors; Up-Regulation - drug effects
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0088369

It has been suggested that prolonged inflammatory bowel diseases (IBD) may lead to colitis-associated carcinogenesis (CAC). We previously observed that the NF-κB activation in colonic epithelial cells is associated with increased tumor necrosis factor receptor 2 (TNFR2) expression in CAC development. However, the mechanism by which epithelial NF-κB activation leading to CAC is still unclear. Myosin light chain kinase (MLCK) has been reported to be responsible for the epithelial permeability associated with TNF signaling. Therefore we focused on the role of MLCK expression via TNFR2 signaling on CAC development. Pro-tumorigenic cytokines such as IL-1β, IL-6 and MIP-2 production as well as INF-γ and TNF production at the lamina propria were increased in the setting of colitis, and further in tumor tissues in associations with up-regulated TNFR2 and MLCK expressions in the epithelial cells of a CAC model. The up-regulated MLCK expression was observed in TNF-stimulated colonic epithelial cells in a dose-dependent fashion in association with up-regulation of TNFR2. Silencing TNFR2, but not TNFR1, resulted in restoration of epithelial tight junction (TJ) associated with decreased MLCK expression. Antibody-mediated blockade of TNF signaling also resulted in restoration of TJ in association with suppressed MLCK expression, and interestingly, similar results were observed with suppressing TNFR2 and MLCK expressions by inhibiting MLCK in the epithelial cells. Silencing of MLCK also resulted in suppressed TNFR2, but not TNFR1, expression, suggesting that the restored TJ leads to reduced TNFR2 signaling. Such suppression of MLCK as well as blockade of TNFR2 signaling resulted in restored TJ, decreased pro-tumorigenic cytokines and reduced CAC development. These results suggest that MLCK may be a potential target for the prevention of IBD-associated tumor development.