Abstract
About this talk
Non-small cell lung cancer (NSCLC) remains difficult to treat because nearly half of cases lack targetable mutations and often develop therapy resistance, making epigenetic reprogramming an attractive therapeutic strategy. This study investigated how STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B, and STAT6 regulate epigenetic and epitranscriptomic events during CD4+ T helper (TH) cell differentiation in NSCLC, aiming to enhance antitumor immunity. Peripheral blood mononuclear cells from NSCLC patients and healthy donors were isolated by Ficoll-Hypaque density-gradient centrifugation, followed by CD4+ T-cell purification using magnetic-activated cell sorting. STAT genes were individually knocked out using CRISPR/Cas9 or overexpressed by nucleofection. Quantitative reverse-transcription PCR assessed 5-methylcytosine (5-mC), N6-methyladenosine (m6A) RNA methylation, TH-differentiation gene expression, and transcription-factor binding. R-loop accumulation at TH-cell-specific loci was also examined, as persistent DNA-RNA hybrids can promote genomic instability and DNA damage. STAT1 and STAT4 depletion increased R-loop formation, DNA methylation, histone deacetylation, and repressive histone methylation, while reducing m6A methylation and NSCLC-cell cytotoxicity; their overexpression produced opposite effects. In contrast, STAT2 and STAT3 depletion or overexpression caused reciprocal patterns, revealing distinct roles among STAT family members. STAT5A, STAT5B, and STAT6 also modulated 5-mC, m6A, histone methylation, and TH-differentiation gene expression, indicating their involvement in epigenetic and epitranscriptomic regulation of T-cell immunity. Overall, STAT1 and STAT4 emerge as key positive regulators of TH-cell differentiation and antitumor immunity in NSCLC, whereas STAT2, STAT3, STAT5A, STAT5B, and STAT6 exhibit context-dependent functions. Targeting STAT-mediated pathways may offer a promising epigenetic strategy to restore immune function and overcome resistance in NSCLC.
Key Words: STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B, STAT6, R-loop, T helper cells, Epigenetic, Epitranscriptomic
Speaker
About the speaker
