DOT1L promotes expression of CD44 through the Wnt/β-catenin signaling pathway in early gastric carcinoma.

To assess telomere silencing 1-like (DOTIL) gene expression within gastric cancer (GC) tissues as well as its function of promoting cancer stem cell (CSC)-mediated epithelial-mesenchymal switching, tissue samples from 8 patients each in 3 stages (normal, low-grade intraepithelial neoplasia (LGIN), as well as early gastric carcinoma (EGC)) were collected for whole-exome sequencing, which revealed differentially expressed genes (DEGs). The DEGs and their prognostic value were verified through TCGA and GTEx analyses. We also verified the role of DOT1L in EGC development. We collected samples from three patients each with LGIN and EGC for single-cell sequencing. We conducted single-cell transcriptomic analysis, DEG analysis, cell‒cell interaction analysis, and pseudotime analysis using R language. Sites and levels of DOT1L, CD44 and DOT1L expression were verified by IF. We found 703 deleterious mutation sites in the LGIN group and 389 deleterious mutation sites in the EGC group. The LGIN as well as EGC categories exhibited increased levels of DOT1L expression compared to the standard category (P<0.05) in TCGA and GTEx. DOT1L also correlated significantly with TMB (P=8.45E-06), MSI (P=0.001), and tumor proliferation index (P=7.17E-09) in the TCGA and GTEx datasets. In single cells, we found that DOT1L promotes CD44 expression via the Wnt/β-catenin signaling pathway and the development for stemness properties within GC. In addition, we found that DOT1L, CD44 and CTNNB1 colocalize and correlate positively. In conclusion, one important CSC regulator in GC, DOT1L may be crucial in coordinating the expression of genes specific to a certain lineage during MSC development.