SAR1A Induces Cell Growth and Epithelial-Mesenchymal Transition Through the PI3K/AKT/mTOR Pathway in Head and Neck Squamous Cell Carcinoma: An In Vitro and In Vivo Study.

OBJECTIVES

Head and neck squamous cell carcinoma (HNSCC) ranks sixth globally, with a 50% five-year survival rate. SAR1A exhibits high expression levels in various tumor types, yet its specific role in HNSCC remains to be clarified.

METHODS

In vitro assays, such as CCK8, EdU, colony formation, wound-healing, transwell, and Western blotting analyses, as well as in vivo assays, such as tumor xenografts and lung metastasis models, were conducted to evaluate the impacts of SAR1A on HNSCC proliferation, migration, and invasion. Transcriptome sequencing and KEGG enrichment pathway analysis revealed evident alterations in the PI3K/AKT/mTOR(PAM) pathways. LY294002 (a PI3K/AKT inhibitor) was used to investigate the role of the PAM pathway in proliferation, migration, and invasion in HNSCC.

RESULTS

Univariate and multivariate Cox regression were conducted to screen SAR1A as a gene prognostic biomarker in HNSCC, and it was validated in the Cancer Genome Atlas (TCGA) database. Functional assays demonstrated that the depletion of SAR1A leads to suppressed proliferation, migration, and invasion of HNSCC cells. This is accompanied by a decrease in the expression of epithelial-mesenchymal transition (EMT)-related markers in HNSCC cell lines. In addition, the diminished capacities of proliferation, migration, and invasion observed in SAR1A knockdown cells were reversed upon the overexpression of SAR1A. Furthermore, RNA-seq and KEGG enrichment analysis demonstrated a significant alteration in the PAM pathway following SAR1A knockdown. LY294002 effectively mitigated the increased proliferation, migration, and invasion induced by SAR1A overexpression.

CONCLUSIONS

SAR1A facilitates HNSCC proliferation and EMT via the PI3K/AKT/mTOR pathway.