Signal Transducer and Activator of Transcription (STAT)-mediated epigenetic and epitranscriptomic regulation of T helper cell differentiation in non-small cell lung cancer

Title: Signal Transducer and Activator of Transcription (STAT)-mediated epigenetic and epitranscriptomic regulation of T helper cell differentiation in non-small cell lung cancer

Abstract:

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. The current study investigates how Signal Transducer and Activator of Transcription (STAT) proteins, especially, STAT1, STAT2, STAT3, and STAT4 regulate epigenetic and epitranscriptomic events during CD4⁺T helper (T_H) cell differentiation in NSCLC, with the goal of enhancing antitumor immunity. Peripheral Blood Mononuclear Cells (PBMCs) 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 (MACS). STAT genes were individually knocked out or overexpressed using CRISPR/Cas9-based approaches, and qRT-PCR was used to assess 5-mC, m⁶A RNA methylation, gene expression, and transcription factor binding. The study also examined R-loop accumulation at T_H-cell-specific loci, given that persistent DNA-RNA hybrids can drive genomic instability and DNA damage. Functionally, STAT1 and STAT4 depletion increased R-loop formation, DNA methylation, histone deacetylation, and repressive histone methylation, while reducing m6A RNA methylation and NSCLC cell cytotoxicity; their overexpression produced the opposite pattern. In contrast, STAT2 and STAT3 depletion or overexpression caused opposite effects, highlighting distinct roles among STAT family members. Overall, STAT1 and STAT4 emerge as key positive regulators of T_H-cell differentiation and antitumor immunity in NSCLC, suggesting that targeting these pathways may offer a promising epigenetic therapeutic approach.

Keywords: STAT1, STAT2, STAT3, STAT4, R-loop, T helper cells, Epigenetic, Epitranscriptomic.

Biography:

Dr. Koustav Sarkar is a Research Associate Professor in Biotechnology at SRM Institute of Science and Technology, Kattankulathur, Chennai, India having earned his PhD at age 28 from Chittaranjan National Cancer Institute/Jadavpur University, Kolkata, india. With 24 years of research experience including a PhD and three postdocs from different universities of USA, he has published 89 high-impact papers and presented at over 100 conferences. His key contributions include isolating immunomodulatory neem leaf glycoprotein with cancer-preventive functions (patent #259434, granted 2014) and discovering WASp's novel nuclear role in Th1 differentiation via epigenetic regulation of the T-BET promoter. He currently studies epigenetic and epitranscriptomic mechanisms in T helper cells of lung cancer.