Interferon regulatory factor 1 (IRF1)

Overview

IRF1, or interferon regulatory factor 1, is a transcription factor that plays a central role in immune and inflammatory gene regulation. It is best known for mediating interferon-responsive transcriptional programs and for integrating signals from pathways such as JAK2/signal transducer and activator of transcription 3 (STAT3) signaling, MAPK signaling, and Mechanistic target of rapamycin (mTOR)-related networks. In cancer and inflammatory biology, IRF1 is often studied as a context-dependent regulator of cell-state transitions, cytokine responses, and immune checkpoint-related pathways.

Recent studies have highlighted IRF1 as a biologically important node linking pathway inhibition to downstream transcriptional reprogramming. Depending on the cellular context, IRF1 can promote proinflammatory responses, regulate genes involved in immune evasion or antitumor immunity, and participate in transcriptional complexes that influence tumor progression and therapy response. Its relevance spans endothelial inflammation, cholangiocarcinoma, non-small cell lung cancer, and KRAS-MAPK-driven adaptive signaling.

Recent Publications Summary

Recent publications have continued to define IRF1 as a transcriptional regulator with broad relevance to inflammation, cancer immunity, and tissue repair. In bone regeneration, CO2-releasing hydrogels were reported to promote osteoblast proliferation and osteogenic differentiation in MC3T3-E1 cells, with mechanistic evidence that IRF1 activates HOXA2 and contributes to enhanced bone healing in a mouse bone defect model 42587203Aug. In a separate endothelial study, mTOR inhibition with rapamycin or torin 1 increased IRF-1 expression, and cytoskeletal changes involving myosin light chain phosphorylation and actin polymerization were linked to the downstream proinflammatory program, including cytokine transcription and endothelial hyperpermeability 42273992Jun.

Several studies positioned IRF1 within tumor immune regulation and immunotherapy response. In urothelial carcinoma, oncogenic PIK3CA mutation was associated with increased tumor immunogenicity through the IRF1-NLRC5-MHC-I axis, based on analyses of patient samples and functional cell-based assays 42413983Jul. In gastric cancer, single-cell transcriptomic analysis identified IRF1 as a potential suppressor of immune resistance, and in vitro experiments showed that IRF1 inhibited cancer cell invasion and promoted apoptosis 42273856Jun. In non-small cell lung cancer, IRF1 was shown to regulate TRIM21 transcription, thereby promoting ubiquitin-mediated degradation of FGL1; artemisinin upregulated this IRF1-TRIM21 axis and, in combination with anti-PD-1 therapy, enhanced antitumor efficacy in high-FGL1 tumors 42020516Apr. metformin was also reported to suppress PD-L1 expression across multiple cancer models by SLC5A11-dependent activation of AMPK and subsequent JAK2-STAT1-IRF1 downregulation, supporting improved checkpoint inhibitor activity in mouse and ex vivo systems 41690450Feb.

IRF1 was further implicated in therapy-induced adaptive signaling and tumor microenvironment remodeling. Prolonged KRAS-MAPK inhibition in pancreatic ductal adenocarcinoma induced interferon and NF-κB signaling, with IRF1 and IRF9 driving TRIM22 expression and promoting a resistant, EMT-like cell state 42008116Apr. In lung adenocarcinoma, multi-omics and machine learning analyses identified IRF1 among core PANoptosis-related genes, with single-cell analyses suggesting cell-specific relevance in the tumor microenvironment 41935997Apr. In large-duct type intrahepatic cholangiocarcinoma, OSMI-1 was reported to suppress MUC16 expression by disrupting the transcriptional complex formed between OGT and IRF1, thereby inhibiting proliferation and migration in cellular and organoid models 41839437Mar.

Beyond cancer, IRF1 has been linked to inflammatory disease mechanisms. In atopic dermatitis, sinomenine attenuated IFN-γ/TNF-α-induced pyroptosis in HaCaT cells, and mechanistic experiments indicated that it downregulated TRAF6 expression by inhibiting its transcriptional regulator IRF1, thereby reducing NLRP3 inflammasome activation and pyroptosis markers including Caspase-1 and GSDMD-N 42394466Jul. Collectively, these studies present IRF1 as a context-dependent regulator connecting interferon signaling, inflammatory injury, and antitumor immunity across diverse disease settings.

What Changes, What Holds

1. IRF1 is newly tied to bone repair and endothelial inflammatory remodeling
NEW DIRECTION Bone-regeneration and endothelial findings extend IRF1 beyond the established immune and inflammatory gene-regulation frame rather than contradicting it. In bone, IRF1 is now implicated in osteoblast and healing programs via HOXA2, suggesting a repair role not covered in the Overview 42587203Aug. In endothelium, mTOR blockade appears to increase IRF1 and feed a cytoskeletal, proinflammatory permeability program, sharpening the link between mTOR-related networks and IRF1-driven vascular inflammation 42273992Jun.

2. IRF1 remains a central checkpoint-linked immune regulator but now has stronger tumor-specific mechanisms
REINFORCES Urothelial, gastric, lung, and metformin studies all support the baseline view that IRF1 sits at the intersection of interferon signaling, immune evasion, and antitumor immunity. The new work does not overturn that account; it specifies how IRF1 can raise tumor immunogenicity, suppress invasion, promote apoptosis, and shape PD-L1 or FGL1-dependent checkpoint responses 42413983Jul42273856Jun42020516Apr41690450Feb. The main advance is mechanistic refinement, not a changed direction.

3. IRF1 is now implicated in therapy resistance and tumor-state remodeling beyond its established signaling roles
NEW DIRECTION Prolonged KRAS-MAPK inhibition-induced IRF1 and IRF9 activity fits the Overview’s mention of adaptive signaling, but the resistant EMT-like state and TRIM22 induction add a more specific resistance program that was not previously established 42008116Apr. Likewise, the OGT-IRF1 transcriptional complex in cholangiocarcinoma introduces a direct co-regulatory mechanism for MUC16 expression, and the PANoptosis-gene analysis broadens IRF1’s tumor microenvironment relevance without displacing the baseline 41839437Mar41935997Apr.

4. IRF1 is newly linked to inflammasome-driven injury in atopic dermatitis
NEW DIRECTION Sinomenine’s effect on IFN-γ/TNF-α-induced pyroptosis identifies IRF1 as a transcriptional upstream node for TRAF6, NLRP3 activation, and GSDMD/Caspase-1-associated epithelial injury, a role the Overview does not cover 42394466Jul. This does not cut against the baseline emphasis on inflammatory gene regulation; it adds a disease-specific tissue-damage mechanism and suggests IRF1 may be a therapeutic lever in inflammatory skin disease.

Overview update candidates: IRF1 in bone repair via HOXA2; IRF1 as an upstream regulator of endothelial hyperpermeability during mTOR inhibition; IRF1-mediated control of TRAF6/NLRP3 pyroptosis in atopic dermatitis; IRF1-dependent TRIM22 induction in KRAS-MAPK inhibitor resistance; OGT-IRF1 control of MUC16 expression in cholangiocarcinoma.