Single-Cell Transcriptomic Analysis Highlights the Impact of NFKB2-Mediated MIF-CD44 Signaling Axis in Endometrioid Endometrial Cancer.

BACKGROUND

The tumor microenvironment (TME) is a complex network driving endometrioid endometrial cancer (EC) progression. Previous analyses of the EC TME were often limited by a lack of detailed cellular annotations. Integrating single-cell RNA sequencing (scRNA-seq) data offers a comprehensive approach to reconstruct the TME, aiming to uncover novel mechanisms and therapeutic targets.

METHODS

We integrated public scRNA-seq data from 15 EC and 5 normal endometrium samples. Through detailed cell annotation, we performed comprehensive bioinformatic analyses, including pseudotime trajectories, copy number variation, and cell communication, to investigate mechanisms of EC development.

RESULTS

We identified nine cell types and characterized subpopulations of epithelial, macrophage, lymphocyte, and stromal fibroblast cells. The SOX9+LGR5- epithelial subtype showed elevated malignancy and NFKB pathway enrichment. The M2_like2 macrophage subtype played a critical role, engaging in robust MIF-(CD74+CD44) mediated communication with SOX9+LGR5- cells. Experimental validation confirmed MIF co-expression with E-cadherin in EC tissues. Furthermore, the transcription factor NFKB2 was found to mediate MIF's effect on the CD44 receptor in malignant epithelial cells. A pericyte-to-fibroblast transition in stromal cells may also support tumor growth, while an increase in CD8 exhausted/Treg cells and a decrease in cytotoxic CD8 cells suggest potential immune evasion.

CONCLUSION

Our single-cell analysis details the EC TME landscape, revealing robust communication between M2_like2 macrophages and SOX9+LGR5- epithelial cells. We highlight a key mechanism where NFKB2 mediates MIF's pro-tumorigenic effects via the CD44 receptor, offering new insights into EC progression and potential therapeutic targets.