CD40 is expressed in the subsets of endothelial cells undergoing partial EndoMT in tumor microenvironment

Abstract

Tumor progression is regulated by endothelial cells undergoing endothelial-mesenchymal transition (EndoMT), a process whereendothelial cells lose their properties and differentiate into mesenchymal cells. TGF-β plays a central role in inducing EndoMT.Cells undergoing EndoMT differentiate through a spectrum of intermediate phases, suggesting that some cells remain in a partialEndoMT state, exhibiting both endothelial and mesenchymal phenotypes. However, detailed analysis of partial EndoMT has beenhampered by the lack of specific markers. In this study, we developed EndoMT reporter endothelial cells (EMRECs), allowing real-time observation of stepwise changes in EndoMT and successful visualization and analysis of the process. RNA sequencing ofmultiple EndoMT stages identified CD40 as a gene specifically upregulated during partial EndoMT. Additionally, analysis of publicsingle-cell RNA sequencing data from 10 types of solid tumors revealed high enrichment of CD40 expression in the partial EndoMTcluster. These findings enhance our understanding of TGF-β-induced EndoMT mechanisms and may lead to new therapeuticstrategies targeting EndoMT-driven cancer progression and metastasis.