AUTHOR=Koester Sean T. , Li Naisi , Dey Neelendu TITLE=RET is a sex-biased regulator of intestinal tumorigenesis JOURNAL=Frontiers in Gastroenterology VOLUME=2 YEAR=2024 URL=https://www.frontiersin.org/journals/gastroenterology/articles/10.3389/fgstr.2023.1323471 DOI=10.3389/fgstr.2023.1323471 ISSN=2813-1169 ABSTRACT=

Ret is implicated in colorectal cancer (CRC) as both a proto-oncogene and a tumor suppressor. We asked whether RET signaling regulates tumorigenesis in an Apc-deficient preclinical model of CRC. We observed a sex-biased phenotype: Apc^Min^/+Ret+/- females had significantly greater tumor burden than Apc^Min^/+Ret+/- males, a phenomenon not seen in Apc^Min^/+ mice, which had equal distributions by sex. Dysfunctional RET signaling was associated with gene expression changes in diverse tumor signaling pathways in tumors and normal-appearing colon. Sex-biased gene expression differences mirroring tumor phenotypes were seen in 26 genes, including the Apc tumor suppressor gene. Ret and Tlr4 expression were significantly correlated in tumor samples from female but not male Apc^Min^/+Ret+/- mice. Antibiotics resulted in reduction of tumor burden, inverting the sex-biased phenotype such that microbiota-depleted Apc^Min^/+Ret+/- males had significantly more tumors than female littermates. Reconstitution of the microbiome rescued the sex-biased phenotype. Our findings suggest that RET represents a sexually dimorphic microbiome-mediated “switch” for regulation of tumorigenesis.