Impaired glycosylation drives golgi stress-mediated gastric tumorigenesis that can be targeted by lectin-drug conjugates II

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. Overall design: To investigate the assciation between muc6 and gastric carcinogenesis, we newly generate Muc6-/- mice and compared gene expression by RNA sequence between WT and MUC6-/- mice.