Discovery of PAK2 as a Key Regulator of Cancer Stem Cell in Head and Neck Squamous Cell Carcinoma Using Multi-Omic Techniques.

Head and neck squamous cell carcinoma (HNSC) is an aggressive malignancy whose progression is closely associated with dysregulation of programed cell death (PCD) pathways and cancer stem cell (CSC) characteristics. To systematically screen for key pathogenic genes, this study performed single-cell analysis on the GSE150321 dataset. The identified cell-specific genes were intersected with PCD- and CSC-related genes, yielding 24 candidate genes for preliminary screening. Further refinement using multiple machine learning (ML) algorithms identified PAK2 as the most central gene among these candidates. Analysis of TCGA and external datasets confirmed that PAK2 is significantly overexpressed in HNSC tissues, demonstrating good diagnostic value and strong association with poor patient prognosis. Functional studies revealed that PAK2 overexpression positively correlates with malignant phenotypes such as metabolic reprograming and tumor metastasis. Notably, PAK2 expression showed a significant negative correlation with antitumor immune status and negatively regulated the infiltration of multiple immune cell types. Spatial transcriptomics and single-cell sequencing analyses revealed PAK2's specific expression patterns within the tumor microenvironment, confirming its influence on the activity of immune-related molecules and immunomodulators. Finally, through Connectivity Map (cMAP) screening and molecular docking, we identified the small molecule compound butein as an effective agent capable of reversing PAK2-mediated procancer molecular features. Butein exhibits stable binding to the PAK2 protein, suggesting its potential as a targeted therapeutic agent. In summary, through multi-omics integration analysis, this study first reveals that PAK2 plays a central role in the pathogenesis of HNSC by regulating PCD, tumor stem cell properties, and the immune microenvironment, and provides a candidate drug for its targeted therapy.