JAK2/STAT3 signaling pathway

Overview

The JAK2/STAT3 signaling pathway is a highly conserved intracellular signal transduction cascade that plays a central role in regulating cell proliferation, differentiation, survival, and immune responses. Janus kinase 2 (JAK2) is a non-receptor tyrosine kinase that physically associates with cytokine receptors on the cell surface; upon receptor engagement — most prominently by interleukin-6 (IL-6), growth factors, or interferons — JAK2 is activated through transphosphorylation and subsequently phosphorylates Signal Transducer and Activator of Transcription 3 (STAT3) at its conserved tyrosine residue (Tyr705). Phosphorylated STAT3 dimerizes, translocates to the nucleus, and drives the transcription of genes governing oncogenesis, angiogenesis, immune evasion, metabolic reprogramming, and inflammatory signaling. Under normal physiology, pathway activation is tightly regulated by negative feedback mechanisms including suppressor of cytokine signaling (SOCS) proteins; dysregulation of this balance underlies a broad spectrum of malignancies and inflammatory diseases.

The pathway occupies a uniquely central position in both oncology and immunology because it integrates signals from the tumor microenvironment, stromal cells, and soluble mediators such as C-X-C motif chemokine ligand 12 (CXCL12) acting through C-X-C chemokine receptor 4 (CXCR4), as well as interleukin-6, to sustain constitutive STAT3 activation in cancer cells. Downstream, the pathway intersects with hypoxia-inducible factor-1α (HIF-1α), Akt1, MAPK1, and nuclear β-catenin (catenin beta 1), contributing to metabolic reprogramming and epithelial-mesenchymal transition (EMT). Given its broad pathological relevance, JAK2/STAT3 has emerged as one of the most intensively pursued therapeutic targets in both small-molecule drug discovery and natural product pharmacology.

Focus of Latest Publications

Recent studies have used the JAK2/STAT3 signaling pathway as a central mechanistic framework across cancer, kidney disease, vascular injury, neuroinflammation, immune disorders, and metabolic disease.

In non-small-cell lung cancer (NSCLC), STAT3 was highlighted as an important contributor to disease progression, and bruceine D was reported to inhibit STAT3-mediated glycolysis, suppressing tumor progression in vitro and in vivo. This places STAT3 at the intersection of oncogenic metabolism and proliferative signaling.

In diabetic kidney disease, bufalin was identified through network pharmacology as a STAT3-targeting compound, and STAT3 knockdown altered ferroptosis-related and tubulointerstitial fibrosis-related indicators. This suggests that STAT3 participates in renal ferroptosis and fibrotic remodeling, with implications for ferrostatin-1-linked ferroptosis biology and broader kidney injury pathways.

In triple-negative breast cancer, SAHA was reported to induce immunogenic cell death, and its efficacy was enhanced by SOCS3 functional replacement; co-treatment reduced pSTAT3 levels and increased BAK expression in MDA-MB-231 cells. This supports a role for STAT3 signaling in survival and resistance phenotypes, and indicates that suppressing STAT3 phosphorylation may favor pro-death signaling.

In gastric cancer, tumor-stromal crosstalk was implicated in STAT3 activation: cancer-associated fibroblast-derived CXCL12 activated CXCR4-dependent STAT3 signaling in vitro, contributing to upstream regulation of PDIA6-SCD1-driven lipid metabolic rewiring. This connects the pathway to the tumor microenvironment and metabolic adaptation.

In interferonopathies related to AGS genes, a multicenter retrospective study evaluated JAK1/2 inhibitors such as baricitinib and ruxolitinib, underscoring the clinical relevance of JAK-family inhibition in inflammatory disease states where downstream STAT signaling is dysregulated.

In anti-aging and neuroimmune research, Codonopsis pilosula polysaccharides were reported to regulate the JAK2-STAT3 signaling pathway to inhibit microglial activation in BV2 cells, with effects linked to the gut microbiota metabolite 3-indole-glyoxylic acid. This suggests a gut-brain-immune axis in which JAK2/STAT3 contributes to neuroinflammatory activation.

In lung squamous cell carcinoma, CXCL2 was associated with the IL-6/JAK2/STAT3 signaling axis and the immune microenvironment, reinforcing the pathway’s role in cytokine-driven tumor-immune interactions.

In myelofibrosis, momelotinib was described as a JAK1/JAK2/ACVR1 inhibitor approved for patients with splenomegaly, symptoms, and moderate-to-severe anemia, and a real-world study examined clinical benefit after ruxolitinib failure. Although the publication focused on treatment outcomes rather than pathway biology alone, it reflects the therapeutic importance of JAK2-centered signaling in myeloproliferative disease.

In hepatocellular carcinoma, endotrophin binding to CD44 activated STAT3 signaling, promoting epithelial-mesenchymal transition, proliferation, and sorafenib resistance. This is consistent with STAT3 acting as a pro-tumor transcriptional regulator in invasion and drug resistance.

In pancreatic cancer, network pharmacology predicted that phenolics from a dusty miller methanol extract target proteins including EGFR and STAT3, suggesting a multi-target anticancer mechanism. Similarly, in prostate cancer, novel napabucasins were developed as potent STAT3 inhibitors, and in glioblastoma, lomerizine showed antitumor effects by inactivating STAT3 across cell lines.

In heart failure, systems pharmacology analysis of Dengzhan Shengmai Capsule identified STAT3 and JAK2 among core therapeutic targets in the chemokine signaling pathway, indicating that the axis may contribute to cardiac remodeling and inflammatory signaling.

In acute liver injury, network pharmacology identified STAT3 as one of the hub genes, again supporting its recurrent appearance as a central inflammatory and stress-response node.

In primary immune thrombocytopenia, CDK8/CDK19 inhibition suppressed STAT3 phosphorylation under interleukin-6-driven conditions and attenuated Th17 polarization, linking the pathway to adaptive immune skewing.

In diabetic nephropathy, Shenxiao decoction ameliorated podocyte injury by upregulating RUNX3 and inhibiting the JAK2/STAT3 signaling pathway, reinforcing the pathway’s role in renal structural injury.

In fibromyalgia-like pain, leptin signaling through ObRb was described as activating JAK2-STAT3, amplifying macrophage-driven neuroinflammation in dorsal root ganglia and sustaining peripheral sensitization. This positions the pathway as a mediator of nociceptive and inflammatory signaling.

In thoracic aortic dissection, Xuefu Zhuyu decoction attenuated vascular smooth muscle cell phenotypic switching and oxidative stress via the JAK2/STAT3/HIF-1α pathway, linking JAK2/STAT3 to vascular remodeling and hypoxia-associated responses.

In ischemia-reperfusion injury, hyperbaric oxygen preconditioning was reported to reprogram neuroimmune metabolism by disrupting the LRG1-HIF-1α-IL-6-STAT3 amplification loop, attenuating pyroptosis. This highlights a feed-forward inflammatory circuit centered on STAT3.

In allergic airway inflammation, xanthatin directly targeted STAT3 and suppressed TSLP release and NK2 cell polarization, indicating a role for STAT3 in type 2-like immune activation.

In acute myeloid leukemia and other hematologic contexts, JAK2 appeared among prognostic mutational variables, while separate work on JAK2 inhibitor discovery emphasized the therapeutic promise of JAK2 inhibition in disease settings driven by aberrant JAK/STAT signaling.

In cancer immunotherapy, engineered CAR T cells expressing constitutively active caSTAT3 or caSTAT5 were used to compare signaling effects, and another study reported that STAT3-biased signaling could enhance CAR T-cell efficacy while lowering systemic toxicity. This suggests that STAT-family signaling can be engineered to shape therapeutic immune cell function.

In metabolic and inflammatory disease, Xiehuang San was reported to target CLCF1-STAT3 to restore insulin signaling in type 2 diabetes, and Pueraria lobata polysaccharides were found to activate hepatic signaling involving AKT, ERK, and STAT3, promoting fatty acid β-oxidation and suppressing inflammation. These findings place STAT3 within broader metabolic regulatory networks.

Across these studies, the JAK2/STAT3 pathway repeatedly emerged as a convergent node linking cytokine signaling, tumor progression, fibrosis, immune polarization, metabolic reprogramming, and tissue injury. The literature also shows that both direct STAT3 inhibition and upstream JAK2 blockade are being pursued as therapeutic strategies.

Key Publications

• Jun Anti-inflammatory and antinociceptive effects of fasudil in a reserpine-induced fibromyalgia model: Role of ROCK-regulated leptin-STAT3 signaling. (Life sciences, 2026, PMID 41942028): "Leptin, a pleiotropic adipocytokine, exerts potent pro-nociceptive effects at the peripheral sensory ganglia through ObRb receptor engagement and downstream JAK2-STAT3 activation, amplifying macrophage-driven neuroinflammation within the DRG and sustaining peripheral sensitization, yet this axis remains a largely unexplored therapeutic target."
• Jun SAHA induces immunogenic cell death in triple negative breast cancer cells and its efficacy is enhanced by SOCS3 functional replacement. (European journal of pharmacology, 2026, PMID 42107746): "In MDA-MB-231 cells, co-treatment reduced pSTAT3 levels and increased BAK expression."
• Jun PDIA6-SCD1 Axis Rewires Lipid Metabolism to Drive Gastric Cancer Progression. (Advanced science (Weinheim, Baden-Wurttemberg, Germany), 2026, PMID 42234404): "Upstream, tumor-stromal interactions may contribute to PDIA6 upregulation, as cancer-associated fibroblast-derived C-X-C motif chemokine ligand 12 (CXCL12) activated C-X-C chemokine receptor 4 (CXCR4)-dependent signal transducer and activator of transcription 3 (STAT3) signaling in vitro."
• Jun Efficacy of JAK1/2 inhibitors in AGS genes-related interferonopathies: A multicenter retrospective observational study with treated vs untreated comparison. (Molecular genetics and metabolism, 2026, PMID 41871482): "This retrospective multicenter study analyzed the efficacy and safety of Janus kinase 1/2 (JAK1/2) inhibitors in 12 patients treated with Baricitinib or Ruxolitinib, compared with 20 untreated patients."
• Jun Structural characterization and anti-aging mechanism of Codonopsis pilosula polysaccharides. (Food research international (Ottawa, Ont.), 2026, PMID 41895995): "Transcriptomics analysis and the BV2 cell verification test demonstrate that CPPS regulates the JAK2-STAT3 signaling pathway to inhibit the activation of microglia, which by affecting the intestinal microbiota's tryptophan metabolite 3-indole-glyoxylic acid (IGA)."
• May Bufalin post-transcriptionally suppresses STAT3 to alleviate renal ferroptosis and tubulointerstitial fibrosis in diabetic kidney disease. (Renal failure, 2026, PMID 42186424): "Network pharmacology analysis identified signal transducer and activator of transcription 3 (STAT3) as a target of bufalin, and knockdown of STAT3 altered the expression of ferroptosis and TIF-related indicators."
• May CXCL2 is associated with IL-6/JAK2/STAT3 signaling and the immune microenvironment in lung squamous cell carcinoma. (Functional & integrative genomics, 2026, PMID 42151497): "...which was linked to modulation of the interleukin-6, Janus kinase 2, and signal transducer and activator of transcription 3 signaling axis."
• May In-silico prediction of multi‑target mechanisms of Pinellia ternata phytochemicals in lung cancer: Evidence from a graph‑attention‑guided virtual screening and multi‑scale simulations. (PloS one, 2026, PMID 42149884): "the potential targets of Pinellia ternata highly overlap with lung cancer pathological genes, with FGFR4, CDK2, JAK2, KDR, PAK4, PTK2 and PDGFRA being the core."
• May Clinical benefit and predictors of response to momelotinib after ruxolitinib failure: A cooperative real-world study. (Cancer, 2026, PMID 42118670): "Momelotinib, a JAK1/JAK2/ACVR1 inhibitor, is approved for treating myelofibrosis with splenomegaly, symptoms, and moderate-to-severe anemia."
• May Endotrophin- and CD44-Mediated Heterotypic Signaling Mediates Tumor-Stroma Cross-talk and Facilitates Malignant Progression in Hepatocellular Carcinoma. (Cancer research, 2026, PMID 41671381): "ETP binding to CD44 activated STAT3 signaling, promoting epithelial-mesenchymal transition (EMT), proliferation, and sorafenib resistance."