WEI-TING KUOTSUNG-CHUN LEEYang H.-Y.Chen C.-Y.Au Y.-C.Lu Y.-Z.Wu L.-L.SHU-CHEN WEIYEN-HSUAN NIBEEN-REN LINChen Y.Tsai Y.-H.Kung J.T.Sheu F.Lin L.-W.LINDA CHIA-HUI YU2021-08-192021-08-1920151350-9047https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941173166&doi=10.1038%2fcdd.2014.240&partnerID=40&md5=aeff996cd0c320292ca2bea3e8a4c9b7https://scholars.lib.ntu.edu.tw/handle/123456789/578358Colorectal carcinoma (CRC) is characterized by unlimited proliferation and suppression of apoptosis, selective advantages for tumor survival, and chemoresistance. Lipopolysaccharide (LPS) signaling is involved in both epithelial homeostasis and tumorigenesis, but the relative roles had by LPS receptor subunits CD14 and Toll-like receptor 4 (TLR4) are poorly understood. Our study showed that normal human colonocytes were CD14+TLR4-, whereas cancerous tissues were CD14+ TLR4+, by immunofluorescent staining. Using a chemical-induced CRC model, increased epithelial apoptosis and decreased tumor multiplicity and sizes were observed in TLR4-mutant mice compared with wild-type (WT) mice with CD14+ TLR4+ colonocytes. WT mice intracolonically administered a TLR4 antagonist displayed tumor reduction associated with enhanced apoptosis in cancerous tissues. Mucosa-associated LPS content was elevated in response to CRC induction. Epithelial apoptosis induced by LPS hypersensitivity in TLR4-mutant mice was prevented by intracolonic administration of neutralizing anti-CD14. Moreover, LPS-induced apoptosis was observed in primary colonic organoid cultures derived from TLR4 mutant but not WT murine crypts. Gene silencing of TLR4 increased cell apoptosis in WT organoids, whereas knockdown of CD14 ablated cell death in TLR4-mutant organoids. In vitro studies showed that LPS challenge caused apoptosis in Caco-2 cells (CD14+ TLR4-) in a CD14-, phosphatidylcholine-specific phospholipase C-, sphingomyelinase-, and protein kinase C-ζ-dependent manner. Conversely, expression of functional but not mutant TLR4 (Asp299Gly, Thr399Ile, and Pro714His) rescued cells from LPS/CD14-induced apoptosis. In summary, CD14-mediated lipid signaling induced epithelial apoptosis, whereas TLR4 antagonistically promoted cell survival and cancer development. Our findings indicate that dysfunction in the CD14/TLR4 antagonism may contribute to normal epithelial transition to carcinogenesis, and provide novel strategies for intervention against colorectal cancer. ? 2015 Macmillan Publishers Limited All rights reserved.[SDGs]SDG3CD14 antigen; lipopolysaccharide; phosphatidylcholine; phospholipase C; protein kinase C zeta; receptor subunit; sphingomyelin phosphodiesterase; toll like receptor 4; CD14 antigen; toll like receptor 4; apoptosis; Article; CACO 2 cell line; cancer tissue; cell death; cell survival; colon carcinogenesis; controlled study; epithelial mesenchymal transition; epithelium cell; gene silencing; human; human cell; in vitro study; mucosa; mutant; priority journal; wild type; animal; Caco-2 cell line; carcinogenesis; colon; colorectal tumor; epithelium cell; genetics; metabolism; mouse; pathology; physiology; signal transduction; Animals; Antigens, CD14; Apoptosis; Caco-2 Cells; Carcinogenesis; Colon; Colorectal Neoplasms; Epithelial Cells; Humans; Mice; Signal Transduction; Toll-Like Receptor 4journal article10.1038/cdd.2014.240256331972-s2.0-84941173166