Kaiso is required for MTG16-dependent effects on colitis-associated carcinoma

SP Short, CW Barrett, KR Stengel, FL Revetta… - Oncogene, 2019 - nature.com
SP Short, CW Barrett, KR Stengel, FL Revetta, YA Choksi, LA Coburn, MK Lintel…
Oncogene, 2019nature.com
The myeloid translocation gene family member MTG16 is a transcriptional corepressor that
relies on the DNA-binding ability of other proteins to determine specificity. One such protein
is the ZBTB family member Kaiso, and the MTG16: Kaiso interaction is necessary for
repression of Kaiso target genes, such as matrix metalloproteinase-7. Using the
azoxymethane and dextran sodium sulfate (AOM/DSS) murine model of colitis-associated
carcinoma, we previously determined that MTG16 loss accelerates tumorigenesis and …
Abstract
The myeloid translocation gene family member MTG16 is a transcriptional corepressor that relies on the DNA-binding ability of other proteins to determine specificity. One such protein is the ZBTB family member Kaiso, and the MTG16:Kaiso interaction is necessary for repression of Kaiso target genes, such as matrix metalloproteinase-7. Using the azoxymethane and dextran sodium sulfate (AOM/DSS) murine model of colitis-associated carcinoma, we previously determined that MTG16 loss accelerates tumorigenesis and inflammation. However, it was unknown whether this effect was modified by Kaiso-dependent transcriptional repression. To test for a genetic interaction between MTG16 and Kaiso in inflammatory carcinogenesis, we subjected single and double knockout (DKO) mice to the AOM/DSS protocol. Mtg16−/ mice demonstrated increased colitis and tumor burden; in contrast, disease severity in Kaiso−/ mice was equivalent to wild-type controls. Surprisingly, Kaiso deficiency in the context of MTG16 loss reversed injury and pro-tumorigenic responses in the intestinal epithelium following AOM/DSS treatment, and tumor numbers were returned to near to wild-type levels. Transcriptomic analysis of non-tumor colon tissue demonstrated that changes induced by MTG16 loss were widely mitigated by concurrent Kaiso loss, and DKO mice demonstrated downregulation of metabolism and cytokine-associated gene sets with concurrent activation of DNA damage checkpoint pathways as compared with Mtg16−/−. Further, Kaiso knockdown in intestinal enteroids reduced stem- and WNT-associated phenotypes, thus abrogating the induction of these pathways observed in Mtg16−/− samples. Together, these data suggest that Kaiso modifies MTG16-driven inflammation and tumorigenesis and suggests that Kaiso deregulation contributes to MTG16-dependent colitis and CAC phenotypes.
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