EZH2 Inhibition Promotes Tumor Immunogenicity in Lung Squamous Cell Carcinomas

Area of Science:

• Oncology
• Immunology
• Epigenetics

Background:

• Resistance to immune checkpoint inhibitors (ICI) in lung squamous cell carcinoma (LSCC) is linked to immune suppression and poor antigen presentation.
• The epigenetic enzyme enhancer of zeste 2 (EZH2) plays a role in regulating gene expression within the tumor microenvironment.

Purpose of the Study:

• To investigate if inhibiting EZH2 can enhance ICI response in LSCC.
• To determine the molecular mechanisms by which EZH2 inhibition affects tumor immunogenicity.

Main Methods:

• In vitro studies using LSCC cell lines and 3D organoids.
• Chromatin immunoprecipitation sequencing (ChIP-seq) to analyze histone modifications.
• In vivo studies using autochthonous and syngeneic LSCC models treated with EZH2 inhibitors and anti-PD1 immunotherapy.
• Single-cell RNA sequencing and immune cell profiling.

Main Results:

• EZH2 inhibition increased the expression of MHC class I and II (MHCI/II) at both mRNA and protein levels.
• ChIP-seq confirmed altered histone marks at key gene loci, indicating EZH2's regulatory role.
• Combination therapy of EZH2 inhibition and anti-PD1 immunotherapy demonstrated significant tumor control in vivo.
• Single-cell analysis revealed phenotypic shifts in immune cells towards a less suppressive state.

Conclusions:

• EZH2 inhibition can overcome resistance to ICI by enhancing antigen presentation and modulating the immune microenvironment in LSCC.
• These findings support the clinical translation of combining EZH2 inhibitors with immunotherapy for LSCC treatment.