Human Papilloma Virus does not fully inactivate p53 cellular activity in HNSCC

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Head and neck squamous cell carcinoma (HNSCC) is a significant global health issue.
• p53 inactivation is a common event in HNSCC, occurring via TP53 mutations or HPV-mediated degradation.
• Human papillomavirus-positive (HPV+) HNSCC generally has better outcomes than HPV-negative HNSCC, despite p53 alterations.

Purpose of the Study:

• To investigate the role and activity of wild-type (WT) p53 in HPV+ HNSCC.
• To determine if residual p53 activity influences tumor progression and patient survival.
• To identify potential therapeutic vulnerabilities associated with p53 status in HPV+ HNSCC.

Main Methods:

• Analysis of human tumor data for survival outcomes based on HPV and TP53 status.
• Experimental genetic ablation of WT p53 in HPV+ HNSCC cell lines.
• Transcriptomic analysis to assess p53-regulated gene expression.
• Analysis of methylation patterns, chromosomal alterations, and PI3K-AKT signaling pathways.

Main Results:

• WT p53 status in HPV+ HNSCC correlates with significantly better survival outcomes compared to HPV+ TP53-mutant and HPV-negative cases.
• Genetic ablation of WT p53 in HPV+ HNSCC cells increased proliferation, migration, and invasion.
• p53 continues to regulate gene expression in HPV+ HNSCC, and WT p53 status is associated with tumor-suppressive methylation and suppressed PI3K-AKT signaling.
• Loss of WT p53 led to increased PI3K p110α, reduced INPP5D, and enhanced sensitivity to PI3K inhibition.

Conclusions:

• The study challenges the notion of complete p53 inactivation in HPV+ HNSCC, revealing persistent tumor-suppressive p53 functions.
• Residual WT p53 activity plays a critical role in HNSCC pathogenesis and patient prognosis.
• TP53 status may be valuable for stratifying HPV+ HNSCC patients for treatment decisions and suggests PI3K pathway inhibition as a therapeutic strategy.