Tumor-derived exosomes elicit cancer-associated fibroblasts shaping inflammatory tumor microenvironment in head and neck squamous cell carcinoma

Objectives: Exosome-mediated reciprocal crosstalk between tumor and stromal cells plays a crucial role in tumor development and progression. This study investigated whether exosomes released from head and neck squamous cell carcinoma (HNSCC) tumor cells can convert normal fibroblasts into cancer-associated fibroblasts (CAF)-like cells and further analyzed the functional characterization of fibroblasts educated by tumor-derived exosomes.Materials and methods: Exosomes secreted from HNSCC cell lines were isolated and normal fibroblasts were established from normal oropharyngeal mucosa. The effects of the exosomes on fibroblasts were examined by proliferation and migration assays, and exosome-educated fibroblasts were analyzed for the expression of eight genes (IL1B, IL6, CXCL8, TGFB1, ACTA2, FAP, CD274, and PDCD1LG2) by RT-qPCR. Moreover, T cells or CD14-positive cells were co-cultured with culture supernatants from exosome-educated fibroblasts. T-cell proliferation and macrophage polarization were examined using flow cytometry. Then, RNA sequencing (RNA-seq) of exosome-educated fibroblasts and the corresponding control fibroblasts was performed. Results: Tumor-derived exosomes enhanced fibroblast proliferation and migration. Moreover, gene expression analysis revealed upregulation of the gene expression of proinflammatory cytokines and immunoregulatory genes, and activated fibroblast marker genes. The culture supernatants of tumor-derived exosome-educated fi-broblasts suppressed T cell proliferation and the induction of protumoral macrophages compared with those of control fibroblasts. Next, comprehensive RNA-seq analysis data revealed the activation of 11 signaling pathways, including IL -6-and IL-17-related signaling. Conclusion: These results indicate that HNSCC tumor cells induce and/or differentiate into CAFs through exosome-based cell-to-cell communication to create an inflammatory tumor microenvironment.

Automated summary

This study investigates the role of exosome-mediated crosstalk between tumor and stromal cells in HNSCC. It demonstrates that exosomes released from HNSCC tumor cells can convert normal fibroblasts into CAF-like cells and influence their gene expression and function. These findings highlight the importance of exosome-based cell-to-cell communication in creating an inflammatory tumor microenvironment.