Jul 2026· Journal of Experimental & Clinical Cancer Research· 0 citations
TL;DR
Target neutralization of SAA1 synergized robustly with osimertinib to reverse immunosuppressive remodeling and induce profound tumor regression in multiple preclinical models, highlighting SAA1 neutralization as a tractable combinatorial strategy to enhance EGFR-TKI efficacy in LUAD.
Abstract
Acquired resistance significantly limits the long-term clinical benefit of osimertinib in EGFR-mutant lung adenocarcinoma (LUAD). However, the early non-genetic adaptations and microenvironmental crosstalk that enable initial tumor survival remain poorly defined. This study aimed to elucidate the epigenetic-immune mechanisms driving osimertinib resistance and to identify novel actionable therapeutic targets.
We integrated transcriptomic profiling and clinical cohort analyses to identify therapy-induced secreted factors during the evolution of EGFR-TKI resistance. The upstream regulatory mechanisms were characterized using ChIP, Co-IP, and dual-luciferase reporter assays. The dual functional roles of the identified factor, serum amyloid A1 (SAA1), in tumor-intrinsic signaling and macrophage polarization were investigated in vitro. Finally, the therapeutic efficacy of combining SAA1 neutralization with osimertinib was evaluated across patient-derived organoids, xenografts, and immunocompetent spontaneous lung tumor models.
We identified SAA1 as a critical therapy-induced secreted factor that progressively increases during the transition from drug tolerance to established resistance, which negatively correlates with clinical outcomes in patients receiving osimertinib. Mechanistically, osimertinib treatment suppressed the ERK-dependent phosphorylation of the transcriptional repressor GATAD2A at Ser114. This event destabilized the NuRD complex, thereby relieving the epigenetic transcriptional repression of SAA1. Secreted SAA1 promoted therapeutic resistance through dual mechanisms: activating the autocrine TLR4/NF-κB survival signaling in tumor cells and inducing the paracrine polarization of pro-tumorigenic SPP1⁺ macrophages. Therapeutically, targeted neutralization of SAA1 synergized robustly with osimertinib to reverse immunosuppressive remodeling and induce profound tumor regression in multiple preclinical models.
Our findings define a novel therapy-induced ERK/GATAD2A/SAA1 epigenetic-immune axis that drives acquired resistance to osimertinib. SAA1 acts as a pivotal bridge between tumor-intrinsic survival adaptations and microenvironmental immune suppression, highlighting SAA1 neutralization as a tractable combinatorial strategy to enhance EGFR-TKI efficacy in LUAD.
Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have markedly improved outcomes in EGFR-mutant lung adenocarcinoma (LUAD), yet acquired resistance to the third-generation inhibitor osimertinib remains inevitable. Although metabolic reprogramming is increasingly recognized as a driver of therapeutic resistance, the epigenetic consequences of lactate accumulation and their functional relevance in osimertinib resistance are poorly understood. Here we report that osimertinib-resistant LUAD cells exhibit enhanced glycolytic flux, increased intracellular lactate levels, and elevated histone H4 lysine 8 lactylation (H4K8la). Integrative transcriptomic analysis revealed significant enrichment of cell-cycle–associated pathways in resistant tumors, despite downregulation of canonical Cyclin B1 and Cyclin D1. Among the upregulated genes, GAS2L3 emerged as a prominent candidate. Genome-wide CUT&Tag profiling demonstrated enrichment of H4K8la at the GAS2L3 promoter, which was confirmed by ChIP–qPCR. Functionally, GAS2L3 overexpression accelerated S/G2–M progression and promoted proliferation under drug pressure, whereas its silencing induced cell-cycle arrest and restored osimertinib sensitivity both in vitro and in xenograft models. Notably, resistant cells displayed elevated P53 expression without induction of its canonical effector P21, indicating checkpoint uncoupling and a noncanonical mode of cell-cycle regulation. Mechanistically, glycolysis inhibition reduced H4K8la and GAS2L3 expression and partially re-sensitized resistant cells, while exogenous lactate restored H4K8la levels and resistance phenotypes, establishing a metabolically driven epigenetic circuit. Clinically, high GAS2L3 expression was associated with shorter progression-free survival in osimertinib-treated patients. Collectively, our findings identify a glycolysis–H4K8la–GAS2L3 axis that drives noncanonical cell-cycle reprogramming independently of classical Cyclin–CDK activation, thereby promoting acquired osimertinib resistance. These results uncover a metabolism-epigenetics–cell cycle interface that may represent a therapeutic vulnerability in EGFR-mutant LUAD.
Shu-Man Zhen, Xiaohui Bai, Shutang Liu et al.· Cell Death Discovery· 0 citations
Abstract Background Metabolic reprogramming within the tumor microenvironment is a pivotal barrier to effective immune checkpoint blockade (ICB). While programmed death ligand 1 (PD-L1) is well characterized as a ligand inhibiting T-cell function, its intrinsic ‘reverse signaling’ role in regulating tumor metabolism and shaping the immune landscape remains poorly understood. Here, we investigated the metabolic determinants of resistance to anti-programmed cell death protein 1 (anti-PD-1) therapy and the underlying molecular mechanisms. Methods Integrated metabolomics and transcriptomics were performed on tumor samples from patients with non-small cell lung cancer and cell lines. Mechanisms were delineated using RNA sequencing, cleavage under targets and tagmentation assays, metabolic flux analysis, and coculture systems. The therapeutic efficacy of targeting metabolic effectors was evaluated in syngeneic mouse models and correlated with immune profiling. Results We identified a distinct metabolic signature characterized by aberrant pyruvate accumulation in patients resistant to anti-PD-1 therapy. Mechanistically, we demonstrate that antibody-mediated ligation of PD-L1 triggers an intrinsic endoplasmic reticulum (ER) stress response via the PERK–ATF4–CHOP axis. ATF4 acts as a transcriptional activator that directly upregulates pyruvate dehydrogenase kinase 4 (PDK4) (blocking pyruvate oxidation) and glutaminase (GLS) (promoting glutaminolysis), creating a ‘dual-hit’ metabolic rewiring that drives intracellular pyruvate build-up. Subsequently, tumor-secreted pyruvate is taken up by tumor-associated macrophages (TAMs) via MCT1, inducing mitochondrial reactive oxygen species accumulation and driving them into a state of cellular senescence. These senescent TAMs upregulate PD-L1 via STAT3 signaling, thereby reinforcing an immunosuppressive feedback loop. Pharmacological inhibition of PDK4 and GLS effectively abolished pyruvate accumulation, prevented macrophage senescence, and restored CD8+ T-cell cytotoxicity. Conclusions Our study identifies a novel ‘PD-L1–ER stress–pyruvate–macrophage senescence’ axis as a key mechanism underlying primary resistance to ICB. These findings highlight the non-canonical reverse-signaling function of PD-L1 in metabolic remodeling and propose that targeting the PDK4/GLS-dependent pyruvate surge offers a promising therapeutic strategy to sensitize tumors to anti-PD-1 immunotherapy.
Wen-Xin Lian, Hui Yang, Yu-Qi Zhang et al.· Journal for ImmunoTherapy of...· 0 citations
BACKGROUND
Metabolic reprogramming fuels colorectal cancer (CRC), yet upstream regulators that lock cells into a glycolytic state remain incompletely defined.
METHODS
We integrated single-cell and spatial transcriptomics with GWAS-eQTL-Mendelian randomization to nominate CRC-associated candidate genes, and profiled their expression, spatial localization, and prognostic value in patient cohorts. The function of MTFR1 was tested by proliferation, migration/invasion, EMT marker analysis, and Seahorse extracellular-flux assays. Mechanisms were interrogated using MeRIP-qPCR, mRNA stability, and dual-luciferase assays. In vivo relevance was evaluated in subcutaneous xenografts.
RESULTS
MTFR1 emerged as a CRC-associated gene whose high expression was associated with poorer overall and disease-free survival. MTFR1 silencing curtailed proliferation, migration and invasion, reversed EMT marker changes, reduced glycolytic rate and ATP output, and increased mitochondrial respiration. In mice, stable MTFR1 knockdown significantly restrained tumor growth. Mechanistically, METTL3 deposited m^6A on MTFR1 transcripts, while IGF2BP2 bound MTFR1 mRNA and enhanced its stability, thereby sustaining MTFR1 expression.
CONCLUSION
A METTL3-m^6A-IGF2BP2 axis maintains MTFR1 expression to drive glycolytic reprogramming and CRC progression. MTFR1 represents a prognostic biomarker and a potential therapeutic node linking epitranscriptomic regulation to metabolic adaptation in CRC.
Li-Qiang Wei, Deng-He Liu, Chun-Yu Lin et al.· Journal of Gastroenterology...· 0 citations
Although osimertinib is an effective third-generation EGFR inhibitor for EGFR-mutant NSCLC, the emergence of acquired resistance continues to limit its long-term clinical benefit. However, the early cellular adaptations that allow residual tumor cells to survive osimertinib exposure are not fully understood. Here, we combined patient-derived NSCLC samples, transcriptomic analyses, cellular experiments, and xenograft models to determine whether prostaglandin E2 receptor subtype 2 (EP2) contributes to osimertinib-tolerant persister (OTP) cells. EP2 was markedly upregulated in OTP NSCLC cells and patient-derived tumor tissues. Mechanistically, EP2 activation induced Ser641 site-specific phosphorylation of glycogen synthase (GYS1), which in turn led to aberrant glycogen accumulation, suppressed glycolytic metabolism, and elevated intracellular succinate levels. The accumulated succinate stabilized hypoxia-inducible factor-1α (HIF-1α), thereby driving the transcription of proinflammatory cytokines, including interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). This metabolic-inflammatory feedback loop enhanced cancer cell survival and facilitated the development of OTPs. Additionally, genetic or pharmacologic inhibition of EP2 effectively reversed these pathogenic alterations, restored osimertinib sensitivity in OTP cells, and attenuated tumor growth in xenograft models. Clinically, high expression levels of EP2, phosphorylated GYS1, and HIF-1α in tumor tissues correlated with poor therapeutic response to osimertinib, and elevated serum concentrations of inflammatory cytokines in NSCLC patients. Collectively, EP2 serves as a critical regulator linking metabolic reprogramming and inflammatory signaling to OTPs. These findings suggest that EP2 blockade may serve as a rational combination strategy for limiting early adaptive resistance and improving responses to EGFR-TKIs in EGFR-mutant NSCLC.
Haiyang Yu, Ling Lu, Xue Hu et al.· International Immunopharmaco...· 0 citations
Elucidating the complex molecular drivers of non-small cell lung cancer (NSCLC) and identifying novel therapeutic targets are urgently needed. Although circPRKCA is implicated in tumorigenesis, its role in NSCLC remains poorly characterized. This study investigates the biological functions and regulatory mechanisms of circPRKCA in NSCLC. CircPRKCA expression and downstream target expression were assessed via qRT-PCR and Western blotting. In vitro functional assays evaluated circPRKCA's role in NSCLC cells. Regulatory mechanisms were further examined using database analysis, RNA immunoprecipitation (RIP), and dual-luciferase reporter assays. In vivo tumor growth was evaluated in mouse xenograft models. CircPRKCA was significantly upregulated in NSCLC and promoted tumor growth and metastasis. Our data suggest that circPRKCA may act as a scaffold for RNA-binding proteins (RBPs), potentially facilitating the recruitment of SRSF1 to HIF-1A mRNA, which appeared to correlate with increased HIF-1A stability. HIF-1A overexpression enhanced NSCLC cell proliferation via PKM2-mediated glycolysis. High circPRKCA expression correlated with poor survival in NSCLC patients. CircPRKCA-SRSF1 axis enhanced proliferation and suppressed apoptosis by stabilizing HIF-1A and modulating PKM2-driven glycolysis. These findings reveal novel diagnostic biomarkers and therapeutic strategies for NSCLC.
Hai-Ting Chen, Xing-Xing Jin, Leilei Tao et al.· Experimental Cell Research· 0 citations
BACKGROUND
Although PD-1/PD-L1 inhibitors are central to the management of advanced bladder cancer, most patients fail to achieve a meaningful response. While evidence ties MMT to fibrotic disease, its contribution to bladder cancer has yet to be examined.
METHODS
We assembled and analysed several complementary data modalities-bulk transcriptomes from TCGA-BLCA (n = 408 tumour, 19 normal) and incorporated single-cell RNA-seq, spatial transcriptomics (nine sections), and two independent immunotherapy cohorts (Kim 2019, n = 348; IMvigor210, n = 298)-to characterize MMT cells and construct an 18-gene MMT signature. Through spatial pseudotime analysis, in vitro overexpression, virtual knockout, FIMO motif scanning, and in vivo tumour models, we identified KLF6 as the key MMT driver. Virtual screening (L1000CDS2) and molecular docking (CB-Dock2) were performed to nominate drugs targeting the KLF6-MMT axis.
RESULTS
MMT cells were present in bladder cancer, and the MMT signature was strongly associated with immunotherapy resistance (P = 0.037 for overall survival) and poor prognosis. KLF6 emerged as the key transcriptional driver of MMT, directly binding the ACTA2 proximal promoter. KLF6 overexpression promoted MMT, tumour growth, and PD-L1 upregulation in vivo (P < 0.05 for tumour weight, P < 0.01 for tumour volume), whereas virtual knockout suppressed core MMT effector genes. Spatial analysis revealed enhanced CD274 (PD-L1) expression by MMT cells, which may contribute to immune evasion through engagement of PDCD1 (PD-1) on tumour-infiltrating T cells (P < 0.001). Among the candidates identified by virtual screening, the cardiac glycoside Periplocymarin ranked first (overlap score = 0.375). Docking placed it in the KLF6 C3 pocket-the DNA-binding cleft-with an affinity of -6.5 kcal/mol, a pose consistent with competitive inhibition.
CONCLUSIONS
This study provides the first multi-omics characterization of MMT in bladder cancer, identifies KLF6 as a previously unrecognized driver of this transition, and demonstrates that KLF6-driven MMT upregulates tumour PD-L1 through intercellular crosstalk. Furthermore, virtual screening and molecular docking identify Periplocymarin as a candidate compound targeting the KLF6-MMT axis. Our work thus connects KLF6-driven MMT to PD-L1-mediated immune evasion and suggests that disrupting this programme with Periplocymarin may provide a strategy to overcome immunotherapy resistance.
Yuwen Chen, Zi-Huan Wang, Cheng-Wu He et al.· International Immunopharmaco...· 0 citations
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