Molecular phenotypic linkage between N⁶-methyladenosine methylation and tumor immune microenvironment in...

The crucial role of N⁶-methyladenosine (m⁶A) methylation in anti-tumor immunity and immunotherapy has been broadly depicted. However, the molecular phenotypic linkages between m⁶A modification pattern and immunological ecosystem are expected to be disentangled in hepatocellular carcinoma (HCC), for immunotherapeutic unresponsiveness circumvention and combination with promising drug agents.

Modification patterns of m⁶A methylation were qualitatively dissected according to the large-scale HCC samples profiling. We then determined the immune phenotypic linkages by systematically evaluating their tumor microenvironment composition, immune/stromal-relevant signature, immune checkpoints correlation, and prognostic value. Individual quantification of m⁶A methylation pattern was achieved by m⁶Ascore construction, intensified by longitudinal single-cell analysis of immunotherapy cohort and validated by the transcriptomic profiles of our in-hospital GDPH-HCC cohort. Candidate therapeutic agents were also screened out.

Three distinct m⁶A methylation patterns were determined in high accordance with inflamed-, excluded-, and desert-immunophenotype. To be precise, Immune-inflamed high-m⁶Ascore group was characterized by activated immunity with favorable prognosis. Stromal activation and absence of immune cell infiltration were observed in low-m⁶Ascore phenotype, linked to impaired outcome. Patients with low-m⁶Ascore demonstrated diminished responses and clinical benefits for cohorts receiving immunotherapy. The above credible linkage between m⁶A methylation pattern and tumor immune microenvironment was robustly validated in our GDPH-HCC cohort. Single-cell dynamic change of m⁶A methylation level in exhausted CD8 T cell and fibroblast was depicted in immunotherapy cohort fore and art. Derived from m⁶A methylation pattern, seven potential frontline drug agents were recognized as promising choice for high-m⁶Ascore patients.

Our work bridged the credible linkage between epigenetics and anti-tumor immunity in HCC, unraveling m⁶A modification pattern as immunological indicator and predictor for immunotherapy. Individualized m⁶Ascore facilitated strategic choices to maximize therapy-responsive possibility.