Impaired glycosylation drives golgi stress-mediated gastric tumorigenesis that can be targeted by lectin-drug conjugates
Ontology highlight
ABSTRACT: Downregulation or gene mutation of MUC6, a major component of gastric mucin, is often identified in human gastric cancers. However, the mechanistic role of MUC6 alteration in gastric carcinogenesis remains unclear. Here, using Muc6-deficient mice, we revealed that dysregulated glycosylation in Muc6-deficient gastric epithelium causes aberrant golgi stress responses, resulting in spontaneous gastric cancer development. Muc6-deficient tumor growth is dependent on MAPK activation, which is mediated by golgi stress-induced golph3 upregulation. Glycomic analysis and lectin-binding assays revealed abnormal expression of mannose-rich N-type glycans in Muc6-deficient gastric tumors. Banana lectin-drug conjugates, which bind to mannose-rich glycans, dramatically suppress mannose-rich murine and human gastric cancer growth. Thus, we propose golgi stress responses and aberrant sugar chains as promising therapeutic targets in gastric cancers accompanied with mucin expression disorder.
Project description:Downregulation or gene mutation of MUC6, a major component of gastric mucin, is often identified in human gastric cancers. However, the mechanistic role of MUC6 alteration in gastric carcinogenesis remains unclear. Here, using Muc6-deficient mice, we revealed that dysregulated glycosylation in Muc6-deficient gastric epithelium causes aberrant golgi stress responses, resulting in spontaneous gastric cancer development. Muc6-deficient tumor growth is dependent on MAPK activation, which is mediated by golgi stress-induced golph3 upregulation. Glycomic analysis and lectin-binding assays revealed abnormal expression of mannose-rich N-type glycans in Muc6-deficient gastric tumors. Banana lectin-drug conjugates, which bind to mannose-rich glycans, dramatically suppress mannose-rich murine and human gastric cancer growth. Thus, we propose golgi stress responses and aberrant sugar chains as promising therapeutic targets in gastric cancers accompanied with mucin expression disorder.
Project description:Downregulation or gene mutation of MUC6, a major component of gastric mucin, is often identified in human gastric cancers. However, the mechanistic role of MUC6 alteration in gastric carcinogenesis remains unclear. Here, using Muc6-deficient mice, we revealed that dysregulated glycosylation in Muc6-deficient gastric epithelium causes aberrant golgi stress responses, resulting in spontaneous gastric cancer development. Muc6-deficient tumor growth is dependent on MAPK activation, which is mediated by golgi stress-induced golph3 upregulation. Glycomic analysis and lectin-binding assays revealed abnormal expression of mannose-rich N-type glycans in Muc6-deficient gastric tumors. Banana lectin-drug conjugates, which bind to mannose-rich glycans, dramatically suppress mannose-rich murine and human gastric cancer growth. Thus, we propose golgi stress responses and aberrant sugar chains as promising therapeutic targets in gastric cancers accompanied with mucin expression disorder.
Project description:Gene expression profiles of Bacteroides thetaiotaomicron in vitro during growth on host mucosal polysaccharides as sole carbon sources. All substrates in this series are derived from porcine gastric mucin and include mucin O-glycans and glycosaminoglycans.
Project description:The human C-type lectin Reg3a (HIP/PAP) is an antimicrobial peptide that kills Gram-positive bacteria. Reg3a preserves gut microbiota homeostasis, reinforces intestinal barrier function and thereby helps to fight induced colitis in mice. Transcriptomic data revealed an upregulation of numerous genes involved in the robustness of the intestinal barrier, and the biosynthesis pathway of mucin core 1 and 3 O-glycans.
Project description:Symbiotic interactions between humans and our communities of resident gut microbes (microbiota) play many roles in health and disease. Some gut bacteria utilize mucus as a nutrient source and can under certain conditions damage the protective barrier it forms, increasing disease susceptibility. We investigated how Ruminococcus torques—a known mucin-degrader that remains poorly studied despite its implication in inflammatory bowel diseases (IBDs)— degrades mucin glycoproteins or their component O-linked glycans to understand its effects on the availability of mucin-derived nutrients for other bacteria. We found that R. torques utilizes both mucin glycoproteins and released oligosaccharides from gastric and colonic mucins, degrading these substrates with a panoply of mostly constitutively expressed, secreted enzymes. Investigation of mucin oligosaccharide degradation by R. torques revealed strong fucosidase, sialidase and b1,4-galactosidase activities. There was a lack of detectable sulfatase and weak β1,3-galactosidase degradation, resulting in accumulation of glycans containing these structures on mucin polypeptides. While the Gram-negative symbiont, Bacteroides thetaiotaomicron grows poorly on mucin glycoproteins, we demonstrate a clear ability of R. torques to liberate products from mucins, making them accessible to B. thetaiotaomicron. This work underscores the diversity of mucin-degrading mechanisms in different bacterial species and the probability that some species are contingent on others for the ability to more fully access mucin-derived nutrients. The ability of R. torques to directly degrade a variety of mucin and mucin glycan structures and unlock released glycans for other species suggests that it is a keystone mucin degrader, which may contribute to its association with IBD.
Project description:This experiment continues our investigation of glycosylation in endometrial epithelium. During the menstrual cycle, estrogen and progesterone sensitise the uterus to the implanting embryo. There is a major expansion of Golgi and secretory function with increases in mucin (MUC1) and the appearance of specific glycans. We are using Ishikawa cells as a model for in vitro implantation, and have shown the presence of steroid receptors and alterations in glycosylation after hormone exposure.
Project description:Gene expression profiles of Bacteroides thetaiotaomicron in vitro during growth on host mucosal polysaccharides as sole carbon sources. All substrates in this series are derived from porcine gastric mucin and include mucin O-glycans and glycosaminoglycans. Two different culture formats used: 800ml batch-culture bioreactors and 5ml tube cultures (format is indicated within each sample title). Each set of growths was referenced to a minimal medium glucose reference corressponding to the same culture format. Unfractionated porcine mucosal glycan (PMG) growths were compared to previously published in vivo datasets, which were referenced to the 800ml minimal medium glucose reference dataset.