Cellular and Molecular Biology
Shah, Vyom (School: Jericho High School)
Despite studies linking a high fat diet to colorectal cancer incidence, little is known regarding intestinal adaptation to a high fat diet. As intestinal regeneration is regulated by Canonical Wnt, the role of Arachidonic acid (AA) in the variable expression of Wnt targets and intestinal stemness was investigated. Annotated-cluster, differentiation lineage, gene-level and differential expression analysis of single-cell RNA sequencing data and CUT&RUN analysis elucidated AA’s impact. AA decreased crypt domain frequency (p<.001) and enlarged organoids (p<.001) suggesting decreased differentiation and enhanced stemness. Annotated cluster analysis revealed AA increased stem cell frequencies (p<.001). A lack of cluster relapse in differentiation lineages reveals AA promotes stemness exclusively through symmetric division, not dedifferentiation. Gene-level analysis revealed AA and metabolite, PGE2, increased B-catenin (p<0.001) and B-catenin target gene (p<0.001) expression. As expression was greater in PGE2 than AA (p<0.001), suggesting AA promotes stemness through PGE2 induced canonical Wnt signaling. Differential expression and gene-level analysis revealed S100A6 expression was upregulated two-fold with AA (p<0.0001) and six-fold with PGE2 (p<0.0001) suggesting PGE2 recruits S100A6 to promote B catenin. CUT&RUN analysis identified AA elongates S100A6 promoter regions through histone acetylation. The mechanism linking AA and canonical Wnt presents a potential therapeutic target for stemness in colorectal cancer. Future investigations involve the identification of PGE2 mediated histone acetylation.