Solid tumors such as gastric cancers exploit hypoxia-induced adaptive mechanisms to evade cell death. Here, we identify a hypoxia-triggered signaling axis in which the spliced form of XBP1s transcriptionally activates MY...Solid tumors such as gastric cancers exploit hypoxia-induced adaptive mechanisms to evade cell death. Here, we identify a hypoxia-triggered signaling axis in which the spliced form of XBP1s transcriptionally activates MYDGF. We demonstrate that MYDGF competitively binds the ubiquitin adaptor protein UBQLN1 at the STI1-4 domain, thereby blocking UBQLN1-mediated recognition and endoplasmic reticulum-associated degradation (ERAD) of LCN2. Stabilized LCN2 sequesters redox-active iron and inhibits iron-dependent lipid peroxidation, thereby suppressing ferroptosis. Hypoxia promotes the splicing of XBP1s, which directly binds to the MYDGF promoter, increasing its expression. Genetic disruption of this axis sensitizes gastric cancer cells to ferroptosis inducers both in vitro and in vivo. These findings reveal a previously unrecognized mechanism of hypoxia-induced ferroptosis resistance and suggest that the XBP1-MYDGF-UBQLN1-LCN2 pathway is a therapeutic target for hypoxic tumors.
Solid tumors arise within hostile microenvironments shaped by hypoxia, nutrient deprivation, acidosis, mechanical stress, immune pressure, and therapy-induced insults. Beyond malignant cells, stromal and immune component...Solid tumors arise within hostile microenvironments shaped by hypoxia, nutrient deprivation, acidosis, mechanical stress, immune pressure, and therapy-induced insults. Beyond malignant cells, stromal and immune components, including cancer-associated fibroblasts, endothelial cells, and infiltrating leukocytes, co-evolve with tumor cells to regulate tumor initiation, progression, and therapeutic response. Rather than passively tolerating stress, tumor cells actively reprogram signaling and transcriptional networks, frequently through the induction of stress-responsive membrane proteins. These proteins are typically low or absent under homeostatic conditions but are upregulated by hypoxic, metabolic, inflammatory, or therapeutic stress. By coordinating nutrient uptake, metabolite exchange, cell-matrix interactions, survival signaling, invasion, and immune evasion, stress-responsive membrane proteins function as critical execution nodes that support tumor stress tolerance and evolutionary fitness. In this Review, we summarize major microenvironmental stresses in solid tumors, delineate membrane protein-mediated stress-adaptation mechanisms, and discuss clinically approved and emerging strategies targeting stress-responsive membrane proteins to enhance treatment efficacy and overcome therapeutic resistance.
Rhabdomyosarcoma (RMS) is a malignant soft tissue sarcoma with a skeletal muscle phenotype, accounting for approximately 50% of all pediatric soft tissue sarcomas and 8% of all childhood cancers. Although RMS cells expre...Rhabdomyosarcoma (RMS) is a malignant soft tissue sarcoma with a skeletal muscle phenotype, accounting for approximately 50% of all pediatric soft tissue sarcomas and 8% of all childhood cancers. Although RMS cells express myogenic regulatory factors, they fail to undergo terminal differentiation into mature muscle cells. Transforming growth factor β-activated kinase 1 (TAK1) is a key signaling mediator that activates multiple intracellular pathways, yet its role in RMS has remained unknown. Here, we show that TAK1 expression and activity are markedly elevated in RMS cell lines and patient tumor specimens. RNA-Seq and reverse phase protein array (RPPA) analyses revealed that TAK1 regulates the expression and activity of many molecules involved in cell cycle control, cell proliferation, and oncogenic signaling. Inhibition of TAK1 suppresses RMS cell proliferation, migration, and invasiveness, while also promoting terminal myogenic differentiation. TAK1 inhibits differentiation in RMS, in part, through up-regulating YAP1 signaling. Our results also demonstrate that inducible knockdown of TAK1 in human RMS xenografts retards tumor growth and enhances myogenic differentiation in vivo. Collectively, these findings uncover a previously unrecognized role for TAK1 in RMS growth and differentiation, and suggest that TAK1 can be a potential therapeutic target for the treatment of RMS.
RNA alternative splicing is a fundamental post-transcriptional mechanism that plays a key role in generating protein diversity. Previous studies from our group have shown that overexpression SRSF10 could promote liver ca...RNA alternative splicing is a fundamental post-transcriptional mechanism that plays a key role in generating protein diversity. Previous studies from our group have shown that overexpression SRSF10 could promote liver cancer cell proliferation and invasion. However, its involvement in bladder cancer remains poorly understood. In the present study, we investigated SRSF10 expression using data from TCGA and GEO databases, immunohistochemistry, and proteomics. Functional validation was performed through in vitro and in vivo experiments, RNA sequencing, and bioinformatics analysis. Additionally, Co-Immunoprecipitation was utilized to confirm the interaction between BIN1(12+) and ANXA1. Our results demonstrate that SRSF10 is overexpressed in bladder cancer, with its expression correlating with poor prognosis and advanced clinical stages. Functional assays revealed that SRSF10 knockdown significantly decreased cell proliferation and cisplatin IC50, while its overexpression had the opposite effect. These findings were further validated in xenograft models and clinical samples. Mechanistically, we show that SRSF10 induces the retention of BIN1 exon 12, resulting in the upregulation of the BIN1(12+) isoform. BIN1(12+) directly interacts with and activates ANXA1, thereby contributing to cisplatin resistance. In conclusion, SRSF10 enhances cisplatin resistance in bladder cancer through the BIN1(12+)/ANXA1 signaling axis, suggesting its potential as a therapeutic target for bladder cancer.
A better understanding of functional heterogeneity of tumor cells may lead to the improvement of the diagnosis and development of effective therapies for patients with papillary thyroid cancer (PTC). Here, the transcript...A better understanding of functional heterogeneity of tumor cells may lead to the improvement of the diagnosis and development of effective therapies for patients with papillary thyroid cancer (PTC). Here, the transcriptional heterogeneity and hierarchical trajectory of malignant thyrocytes were investigated by single-cell RNA sequencing analysis in an adult-onset autochthonous mouse model of PTC driven by a BRAF. Within BRAF thyrocytes, we identified distinct subpopulations exhibiting varying degrees of mesenchymal transformation and stability. Further analysis uncovered an epithelial-mesenchymal transition (EMT) trajectory, where malignant subpopulations progress from an intermediate to a more mesenchymal and malignant state. The EMT-related phenotype of each subpopulation was validated with an organoid culture system. Further analysis demonstrated that major malignant subpopulations maintain distinct EMT states through subpopulation-specific pathway usage, whereas transitioning cells undergo a dynamic shift in molecular strategy by using different pathway combinations or distinct gene sets within the same EMT-related pathways along the EMT trajectory. Moreover, metformin diminished the most malignant subpopulation in the PTC mouse model and inhibited EMT potential in both regular and organoid cultures. Importantly, the functional heterogeneity of tumor cells identified in PTC mouse model have clinical relevance. Furthermore, transcriptome dynamics analysis revealed an EMT trajectory-related gene module with substantial predictive value for human PTCs with BRAF. Lastly, our analysis reveals that p53 deficiency lowers the tumorigenic threshold for BRAF and promotes cell state transition towards a more malignant state, rather than altering cellular heterogeneity or the transition trajectory. Subsequent analysis in vitro demonstrated that p53 loss might confer more malignant potential to BRAF thyrocytes through modulating metabolic plasticity. Collectively, our work not only deciphers the functional intra-tumoral heterogeneity of BRAF-drieven PTC but also thereby provides a theoretical foundation for developing EMT-targeted treatment.
Approximately 50% of uveal melanoma (UM) patients develop treatment-resistant liver metastases, surviving less than one year after diagnosis. While BRCA1-associated protein 1 (BAP1) deficiency strongly correlates with UM...Approximately 50% of uveal melanoma (UM) patients develop treatment-resistant liver metastases, surviving less than one year after diagnosis. While BRCA1-associated protein 1 (BAP1) deficiency strongly correlates with UM metastasis, its mechanistic role remains unclear. Through integrated analysis of four UM cohorts and functional experiments validation, we identified S100 calcium binding protein A6 (S100A6) as a key metastasis-associated gene consistently upregulated in BAP1-deficient UM. Mechanistically, BAP1 deficiency enhances H2AK119ub deposition and Pol II recruitment at the S100A6 promoter, activating its transcription. Notably, we discovered that S100A6 functions as a novel ligand of fibroblast growth factor receptor 3 (FGFR3), triggering sustained signaling distinct from canonical ligands and activating inflammatory cancer-associated fibroblasts. Genetic or pharmacological targeting of S100A6-FGFR3 signaling effectively suppressed BAP1-deficient UM metastasis in preclinical models, highlighting the therapeutic potential of targeting this signaling pathway. Overall, our findings establish S100A6 as a critical mediator of hepatic metastasis in BAP1-deficient UM through FGFR3-dependent tumor microenvironment activation, revealing its therapeutic potential.
High-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy. Pre- and post-operative, non-invasive biomarkers for reliable treatment outcome prediction, (minimal) residual disease detection, and...High-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy. Pre- and post-operative, non-invasive biomarkers for reliable treatment outcome prediction, (minimal) residual disease detection, and prognosis are not yet established in clinical practice for these patients. This prospective study quantified circulating tumor cells (CTCs) in 7.5 ml peripheral blood in 56 women with FIGO stages IIIC and IV HGSOC before and after primary cytoreductive surgery and in 9 women with benign ovarian disease. Clinical outcomes were assessed during the median follow-up of 35.4 months. CTCs were detected in 48.2% (27/56) of patients pre-operatively and in 46.4% (26/56) post-operatively, but not in benign controls. Pre-operative CTCs were associated with suboptimal cytoreductive surgery (OR = 15.6, 95% CI: 2.97-127.0, p = 0.0031), worse platinum response (p = 0.0173), lymph node metastases (p = 0.0151), and shorter progression-free (p = 0.0045) and overall survival (p = 0.0241). Post-operative CTC-augmented residual tumor was significantly associated with worse OS (p = 0.047). In multivariable analyses, pre-operative CTCs remained an independent surrogate marker for incomplete debulking, platinum resistance, and poor survival in HGSOC. Therefore, the quantification of CTCs in HGSOC pre- and post-operatively may be used to guide treatment selection, reduce surgical morbidity, improve the healthcare provider's resource allocation and planning, and enhance patient counseling.
Sustained proliferation is a hallmark of tumor cells. Cancer-associated alternative splicing (AS) events can provide proliferative advantages in tumors, suggesting that identifying aberrant RNA splicing events linked to...Sustained proliferation is a hallmark of tumor cells. Cancer-associated alternative splicing (AS) events can provide proliferative advantages in tumors, suggesting that identifying aberrant RNA splicing events linked to proliferation in ovarian cancer (OC) may reveal novel therapeutic targets. In this study, we found that small nuclear ribonucleoprotein polypeptide E (SNRPE) was overexpressed in OC, particularly in the proliferative subtype, and indicated worse clinical prognosis. SNRPE knockdown significantly slowed tumor cell proliferation, inducing G1 phase cell cycle arrest and apoptosis. RNA sequencing analysis identified CTP synthase 1 (CTPS1), the rate-limiting factor in the conversion of UTP to CTP, as a critical downstream effector of SNRPE. Mechanistically, SNRPE deficiency led to the retention of intron 15 in CTPS1 mRNA, triggering the degradation of unspliced transcripts through the nonsense-mediated mRNA decay (NMD) pathway and reducing the level of functional CTPS1. Notably, CTPS1 knockdown significantly suppressed the tumor progression driven by SNRPE overexpression. Given that the loss of CTPS2 was prevalent in OC, OC cell proliferation could be more effectively controlled by the suppression of CTPS1. We propose a strategy to regulate CTPS1 expression by modulating its efficient splicing through SNRPE. Consequently, the SNRPE-CTPS1 axis may represent a potential therapeutic target for OC patients.
Bai J, Araki K, Kurotaki D
… +15 more, Eerdunduleng, Sorin S, Hiramatsu K, Uno N, Hamashima A, Iimori M, Kikuchi K, Terashima M, Kubota S, Kohrogi K, Huang G, Ogawa M, Oshimura M, Kazuki Y, Sashida G
The mechanistic role of trisomy 8 in the development of myelodysplastic syndrome (MDS) remains poorly defined. Here, we generated a trisomy 8 mouse model by transferring a human chromosome 8 into murine embryonic stem ce...The mechanistic role of trisomy 8 in the development of myelodysplastic syndrome (MDS) remains poorly defined. Here, we generated a trisomy 8 mouse model by transferring a human chromosome 8 into murine embryonic stem cells and prospectively examined the effects on hematopoietic stem cells (HSC) by trisomy 8. The expression of inflammatory genes was enhanced, and hematopoietic programs mediated by transcription factors and polycomb repressive complex 2 (PRC2) were dysregulated in trisomy 8 HSC, which impaired their self-renewal and balanced differentiation. Trisomy 8 HSC altered the chromatin accessibility and conformations and activated Y chromosome genes, such as Uty/Kdm6c epigenetic modifier, which is known to demethylate histone H3K27me3 modification. The Uty gene facilitated the activation of PRC2-target and Runx1-target genes in leukemogenesis and drove the proliferation of human trisomy 8 leukemic cells. Since the RUNX1 gene is frequently mutated in patients with trisomy 8 MDS, its deletion attenuated the enhanced expression of inflammatory genes and mitigated the impaired self-renewal of trisomy 8 HSC in mice. Our findings reveal that trisomy 8 altered the transcriptional programs and chromatin conformations in HSC and drove a pre-malignant state through activating the expression of Uty, suggesting a route for the development of trisomy 8 MDS.
Colorectal cancer (CRC) peritoneal metastasis (PM) accounts for 25-35% of stage IV cases. CRC PM carries a median overall survival of 16 months with systemic chemotherapy and an almost 0% 5-year survival rate. The molecu...Colorectal cancer (CRC) peritoneal metastasis (PM) accounts for 25-35% of stage IV cases. CRC PM carries a median overall survival of 16 months with systemic chemotherapy and an almost 0% 5-year survival rate. The molecular mechanisms driving CRC PM remain poorly defined. CRC heterogeneity is classified into four Consensus Molecular Subtypes (CMS1-4), with CRC PM predominantly exhibiting the CMS4 signature-characterized by increased stromal/mesenchymal enrichment and cellular plasticity-features linked to frequent disease progression and therapeutic resistance. Here, we investigated the molecular mechanisms driving CRC PM and CMS4 signature. TWIST1 was identified to be significantly upregulated in CRC PM. We established TWIST1-SPON2 as a novel transcriptional axis contributing to CRC PM tumorigenesis, through mediating tumor-stroma interactions. We identified SPP1, secreted by the tumor stroma, as an upstream regulator of the TWIST1-SPON2 cascade via AKT activation in tumor cells in vitro and in vivo. This defined SPP1-TWIST1-SPON2 signaling circuit is pivotal in shaping the tumor microenvironment and promoting CRC PM progression. The findings establish the SPP1-TWIST1-SPON2 axis as potential biomarkers and therapeutic targets in CRC PM.
Rho-associated coiled-coil kinases (ROCKs) regulate the actin cytoskeleton by controlling cellular functions such as cell contraction, migration and adhesion. Within the ROCK family, two highly homologous isoforms with o...Rho-associated coiled-coil kinases (ROCKs) regulate the actin cytoskeleton by controlling cellular functions such as cell contraction, migration and adhesion. Within the ROCK family, two highly homologous isoforms with overlapping functions exist: ROCK1 and ROCK2. The roles of ROCKs are context-dependent, varying by cell type and microenvironment and have been associated with a variety of diseases, including cancer. Increasing evidence correlates ROCK overexpression with cancer progression, metastasis and therapeutic resistance, while ROCK2 inhibition has demonstrated greater tumour inhibition. By regulating cytoskeletal dynamics and phosphorylating downstream effectors, the RhoA/ROCK2 signalling pathway orchestrates cellular processes including cytoskeletal reorganisation, cellular motility and mediating cell cycle progression with specific roles in the epithelial-mesenchymal transition (EMT), vascular mimicry (VM) and fibrosis. Crosstalk with neighbouring pathways further amplifies these oncogenic effects, but our understanding remains incomplete. This review discusses the role of Rho-associated coiled-coil kinases, ROCK2 in particular, in carcinogenesis.
A genome sequence is not made up of random nucleotides. Instead, it has distinctive features for evolutionary adaptation. Herein, we identified a higher frequency of continuous guanines (G-runs) located downstream of the...A genome sequence is not made up of random nucleotides. Instead, it has distinctive features for evolutionary adaptation. Herein, we identified a higher frequency of continuous guanines (G-runs) located downstream of the transcription start site (TSS) in the non-template strand than that of the template strand by analyzing the genomic region around TSS (TSS ± 1 kb) across different species. G-runs are known to have the propensity to form G-quadruplex structures (G4). By integrative analysis of large-scale multi-omic datasets, predicted G4 structures in TSS downstream region (TSS-to-+300 bp) of the non-template strand were found to be associated with lower promoter DNA methylation, more accessible chromatin, and higher transcript levels. Compared to non-cancer genes, tumor-suppressor genes (TSGs) exhibited a higher G-run frequency in TSS downstream region (TSS-to-+300 bp) of the non-template strand, contributing to both their high transcript levels and resistance to tumor-specific downregulation. These results were successfully validated with independent datasets. Taken together, our study reveals an evolutionarily conserved higher G-run frequency in TSS downstream region (TSS-to-+300 bp) of the non-template strand as a beneficial genetic feature of TSGs for optimizing their function in tumor suppression.
The regulatory role of TGF-β-induced epithelial-mesenchymal transition (EMT) in cancer cell dissemination is well established, but the involvement of N6-methyladenosine (mA) in TGF-β signaling remains obscure. Here, we u...The regulatory role of TGF-β-induced epithelial-mesenchymal transition (EMT) in cancer cell dissemination is well established, but the involvement of N6-methyladenosine (mA) in TGF-β signaling remains obscure. Here, we unveil, for the first time, the mA modification profile in TGF-β-induced gastric cancer (GC) EMT and identify zinc finger protein ZNF460 as a critical mediator of the EMT process. The presence of ZNF460 greatly enhances the EMT process, as well as the invasion and spread of GC cells. Mechanistically, the activation of ZNF460 during the EMT process is mediated by METTL16-dependent mA methylation of ZNF460 mRNA. ZNF460 interacts with histone deubiquitinase USP22 and histone demethylase PHF8 to form a stable complex, which transcriptionally activates SOX4, thereby contributing to the tumor EMT and metastasis. In addition, the ZNF460/USP22/PHF8 complex enhances the transcriptional activity of METTL16 in the nucleus, thus forming a positive feedback loop. Clinically, elevated ZNF460, alone or in combination with overexpression of METTL16 and SOX4, is predictive of poor prognosis. Collectively, our findings identify a novel oncogenic epitranscriptomic axis of METTL16/ZNF460/SOX4 which is involved in generating the EMT phenotype and regulating GC metastasis.
Zhang Y, Xue Z, Zhang N
… +17 more, Zhu Y, Wu Y, Lv M, Zhang Z, Mu F, Xing W, Tang Z, Wang C, Xue Z, Zhou W, Liu X, Li X, Bjerkvig R, Huang B, Han M, Wang J, Wang D
Metastasis remains the primary cause of mortality in lung adenocarcinoma (LUAD) patients. However, the molecular mechanisms underlying LUAD cell metastasis are only partially elucidated. Here, by performing integrated bi...Metastasis remains the primary cause of mortality in lung adenocarcinoma (LUAD) patients. However, the molecular mechanisms underlying LUAD cell metastasis are only partially elucidated. Here, by performing integrated bioinformatic analysis of clinical data, RNA-binding protein (RBP) NOVA2 is identified as a pivotal LUAD metastasis-associated regulator. NOVA2 expression is elevated in metastatic LUAD tissues and correlates with poor prognosis of LUAD patients. Functionally, NOVA2 depletion suppresses epithelial-mesenchymal transition (EMT), migration, and invasion in vitro, and attenuates LUAD cell metastasis in vivo. Mechanistically, histone acetyltransferase p300 augments H3K27 acetylation level and facilitates the binding of STAT3 to the NOVA2 promoter, which in turn promotes NOVA2 transcription. Increased NOVA2 expression induces exon skipping (exons 6-7) in SMAD4 to generate a truncated splicing isoform (termed Δ-SMAD4). The resulting Δ-SMAD4 isoform evades E3 ubiquitin ligase β-TrCP-mediated ubiquitination, maintaining its ability to form complex with SMAD3 (R-SMAD) and sustain TGF-β/SMAD signaling. Moreover, in NOVA2-overexpressing LUAD cells, Δ-SMAD4 knockdown has stronger inhibitory effects on TGF-β-induced EMT and invasion than does SMAD4 knockdown. In summary, our findings identify a novel mechanism by which STAT3-mediated transcriptional upregulation of NOVA2 promotes SMAD4 splicing in metastatic LUAD, and suggest that the STAT3-NOVA2-Δ-SMAD4 axis drives EMT and LUAD metastasis, which may be a promising therapeutic target for treating LUAD.
Recent studies have demonstrated that a subset of long "noncoding" RNAs (lncRNAs) produce functional polypeptides and proteins. In this study, we discovered a 132 amino acid protein in human breast cancer cells named XCP...Recent studies have demonstrated that a subset of long "noncoding" RNAs (lncRNAs) produce functional polypeptides and proteins. In this study, we discovered a 132 amino acid protein in human breast cancer cells named XCP (X-linked Cancer-associated Polypeptide), which is encoded by lncRNA1456 (a.k.a. RHOXF1P3), a transcript previously thought to be noncoding. lncRNA1456 is a pancreas- and testis-specific RNA whose gene is located on chromosome X. We found that the expression of lncRNA1456 and XCP is highly upregulated in the luminal A, luminal B, and HER2 molecular subtypes of breast cancer. XCP modulates both estrogen-dependent and estrogen-independent growth of breast cancer cells by regulating cancer pathways, as shown in cell and xenograft models. XCP shares some homology with homeodomain-containing proteins and interacts with the histone demethylase plant homeodomain finger protein 8 (PHF8), which is also encoded by an X-linked gene. Mechanistically, XCP is required for the binding of PHF8 to chromatin. Moreover, XCP stimulates the histone demethylase activity of PHF8 to regulate gene expression in breast cancer cells. These findings identify XCP as a coregulator of PHF8 in the chromatin-dependent regulation of gene expression and emphasize the need to interrogate the potential functional roles of open reading frames originating from noncoding RNAs.
N-methyladenosine (mA) RNA modification is a pivotal post-transcriptional regulator of RNA metabolism and cancer progression. Fat mass and obesity-associated protein (FTO), an mA demethylase, has emerged as a potent onco...N-methyladenosine (mA) RNA modification is a pivotal post-transcriptional regulator of RNA metabolism and cancer progression. Fat mass and obesity-associated protein (FTO), an mA demethylase, has emerged as a potent oncogenic driver across multiple malignancies. In this study, we demonstrate that FTO directly demethylates the primary transcripts of the miR-200b/a/429 cluster, thereby impeding DGCR8-mediated recognition and processing. The ensuing reduction in mature tumor-suppressive miR-200b/a/429 relieves repression of a suite of downstream targets intimately linked to metastasis and cell proliferation, ultimately accelerating tumor growth and lymph-node dissemination in esophageal squamous cell carcinoma (ESCC). Pharmacologic inhibition of FTO restores miR-200b/a/429 cluster expression and partially rescues the oncogenic phenotype elicited by FTO overexpression. Collectively, our findings uncover a previously unrecognized FTO-mA-miR-200b/a/429 axis that propels ESCC progression and highlight FTO as a promising therapeutic target for patients with ESCC.
Wei X, Li X, Pan Y
… +20 more, Zhang Y, Zhong D, Kong W, Wang Y, Yu Z, Shao W, Dong Y, Jiang S, Qiu Z, Zhang Y, Li X, Li Y, Gu S, Tian C, Qin C, Zhu Q, Feng N, Song N, Yao B, Yang Z
Immunotherapy has achieved limited efficacy in prostate cancer (PCa), largely due to its profoundly immunosuppressive tumor microenvironment (TME). However, the metabolic mechanisms underpinning this immune resistance re...Immunotherapy has achieved limited efficacy in prostate cancer (PCa), largely due to its profoundly immunosuppressive tumor microenvironment (TME). However, the metabolic mechanisms underpinning this immune resistance remain poorly defined. Here, we identify lactate dehydrogenase A (LDHA)-driven lactate metabolism as a critical regulator of myeloid-derived suppressor cell (MDSC) activation in PCa. Integrated metabolomic, single-cell, and spatial transcriptomic analyses revealed that LDHA is highly expressed in PCa malignant epithelial cells and correlates with increased lactate production and immune exclusion. LDHA-high tumors exhibited enriched infiltration of polymorphonuclear MDSCs (PMN-MDSCs), which were spatially co-localized with LDHA-positive tumor regions. Mechanistically, lactate uptake through monocarboxylate transporter 1 (MCT1) enhanced PMN-MDSC differentiation and upregulated Arg1 and NOS2, reinforcing T cell suppression. Genetic ablation of LDHA in murine models markedly reduced PMN-MDSC infiltration, restored CD8T cell activity, and inhibited tumor growth. Pharmacological inhibition of LDHA with FX-11 synergized with anti-PD-L1 therapy, producing durable tumor regression. Collectively, these findings define LDHA-driven lactate metabolism as a key metabolic checkpoint in PCa immune evasion and provide a rationale for combining LDHA inhibition with immune checkpoint blockade to overcome immunotherapy resistance.
Immune checkpoint blockade (ICB) therapy for many cancers remains limited in patients' overall response rate. Discovery and development of more effective combinatorial approaches is urgent. Here, through CRISPR/Cas9 gene...Immune checkpoint blockade (ICB) therapy for many cancers remains limited in patients' overall response rate. Discovery and development of more effective combinatorial approaches is urgent. Here, through CRISPR/Cas9 genetic screens, we identify DOT1L as a versatile epigenetic factor that functions to suppress tumor-intrinsic immunity through a dual mechanism. Depletion of DOT1L induces the expression of transposable elements and subsequent type I interferon (IFN) response, and meanwhile lowers ZEB1 levels to further unleash the expression of immune-related genes. In turn, we demonstrate that DOT1L loss or treatment with the clinical stage inhibitor EPZ-5676 sensitizes tumors to ICB with increased immune infiltration in mice. More importantly, EPZ-5676 treatment alone is sufficient to enhance antitumor immunity in humanized mice. TCGA data analysis reveals an inverse correlation between DOT1L expression and IFN signatures across multiple cancer types. These findings provide a rationale for targeting DOT1L to improve tumor immunogenicity and overcome immunotherapy resistance.