HAS1high cancer associated fibroblasts located at the tumor invasion front zone promote oral squamous cell carcinoma invasion via ECM remodeling.

Background: Although tumor cell heterogeneity between the tumor center (TC) and invasion front (IF) of oral squamous cell carcinoma (OSCC) is well documented, the morphological, molecular, and functional characteristics of cancer-associated fibroblasts (CAFs) in these regions remain poorly understood.

Methods: We examined hematoxylin and eosin (H&E)-stained OSCC sections to assess CAF morphology and correlation with patient prognosis. We then isolated paired CAFs from the tumor center (CAF^TC) and invasion front (CAF^IF) of four OSCC patients and compared their ECM-remodeling activity and pro-tumorigenic effects on OSCC cells. Furthermore, RNA sequencing identified differentially expressed genes between CAF^TC and CAF^IF. Finally, based on RNA-seq findings, we knocked down hyaluronan synthase 1 (HAS1) in CAF^IF to evaluate its role in extracellular matrix (ECM) remodeling and tumor invasion.

Results: Compared to CAF^TC, CAF^IF exhibited a plump cell morphology and were associated with shorter disease-free survival. Functionally, CAF^IF showed higher ECM-remodeling activity and more effective ability for promoting OSCC invasion and lymph node metastasis than CAF^TC. RNA-seq identified HAS1 was significantly upregulated in CAF^IF, promoting hyaluronic acid (HA) production and ECM remodeling. HAS1 knockdown in CAF^IF diminished ECM remodeling and attenuated the ability of CAF^IF to promoting OSCC invasion.

Conclusion: CAF^IF with plump cell morphology showed pro-invasive abilities, driven in part by HAS1 overexpression and ECM remodeling, suggesting that targeting HAS1-driven ECM remodeling could be a promising therapeutic strategy.