Targeting the KMT2D-driven Enhancer-Immune-Metabolic axis in HNSCC: Reconciling the paradox for precision therapy

Area of Science:

• Oncology
• Epigenetics
• Immunology

Background:

• Head and neck squamous cell carcinoma (HNSCC) has high mortality due to recurrence, with immune checkpoint blockade (ICB) showing limited efficacy.
• Tumor outcomes depend on complex interactions within the tumor microenvironment, including genomic and epigenetic factors.
• KMT2D (MLL4), a frequently mutated gene in HNSCC, has context-dependent roles in cancer stemness and metabolism.

Purpose of the Study:

• To reconcile the dual roles of KMT2D in HNSCC.
• To propose an "Enhancer-Immune-Metabolic Framework" to understand KMT2D's function.
• To identify therapeutic vulnerabilities in KMT2D-altered HNSCC.

Main Methods:

• Review and synthesis of existing evidence on KMT2D function.
• Analysis of KMT2D's role in rewiring enhancer landscapes and metabolic reprogramming (aerobic glycolysis).
• Investigation of the link between KMT2D, metabolism, and immune evasion, including antigen presentation and myeloid cell activity.

Main Results:

• KMT2D alterations shift enhancer landscapes, favoring aerobic glycolysis via the PER2 axis.
• This metabolic shift promotes immune exclusion by impairing antigen presentation and fostering an immunosuppressive myeloid environment.
• Histone lactylation (H3K18la) may link glycolytic flux to chromatin changes that drive immune evasion.

Conclusions:

• KMT2D-driven enhancer remodeling connects metabolic reprogramming and immune escape in HNSCC.
• KMT2D acts as an epigenetic rheostat, influencing tumor behavior.
• Combination strategies involving DNA damage repair targeting, metabolic interventions, and epigenetic priming may overcome ICB resistance in KMT2D-altered HNSCC.