Tumor Glycolysis Research Articles

Targeting CA9 restricts pancreatic cancer progression through pH regulation and ROS production.

Lactate is a key metabolite produced by glycolytic metabolism, yet it also serves as an energy source for cancer cells. Lactate accumulation in the tumor microenvironment (TME) has been demonstrated to correlate with immunosuppressive TME and tumor progression. As a highly glycolytic tumor, it is crucial to decipher the underlying mechanism in pancreatic ductal adenocarcinoma (PDAC). Bioinformation analysis was used to identify lactate mediated carbonic anhydrase IX (CA9) upregulation. CCK-8, colony formation and mouse xenograft assay were utilized to study the effect of CA9 in PDAC. ECAR, OCR and pHi measurement confirmed the impacts of CA9 in Warburg phenotype. Using confocal microscopy, flow cytometry, qRT-PCR, co-IP, we validated the signaling pathways in PDAC to regulate reactive oxygen species (ROS) production. We confirmed that CA9 is highly expressed in PDAC and positively regulated by lactate levels. CA9 can enhance the proliferative and migratory capabilities of PDAC cells. Pharmacologic inhibition or knockdown of CA9 significantly reduce pHi, increase the intracellular lactate and reverse the Warburg phenotype. The intracellular lactate accumulation caused by CA9 knockdown upregulates ROS and mitochondrial dysfunction. Furthermore, it was discovered that the competitive binding of CA9 with FUS inhibits the facilitation of FUS on NOX4 pre-mRNA splicing. Collectively, our data illustrate that CA9 has a direct regulatory role in pHi homeostasis and ROS production, providing a potential therapeutic target for PDAC treatment.

Swimming upregulates APOL3 through regulating macrophage polarization to inhibit glycolysis and the development of melanoma.

This study investigated the role of swimming exercise in regulating melanoma tumour growth and glycolysis in cancer cells, the specific mechanism involved was also studied. In our study, a murine melanoma tumour model was established to assess the impact of swimming on tumour growth. The mRNA and protein expressions were assessed using qRT-PCR, western blot, and IHC. The metabolic behavior of melanoma cells was examined through lactic acid level measurements and glucose consumption assessments. CCK-8 and colony formation assays were used to detect cell viability and proliferation. ELISA was employed to determine the levels of cytokines secreted by macrophages. The interaction between APOL3 and STAT3 was analyzed by dual luciferase reporter gene and ChIP assays. Our results demonstrated that swimming exercise suppressed melanoma growth in mice by suppressing glycolysis, which might be related to APOL3 upregulation. In addition, downregulation of APOL3 in melanoma was associated with poor prognosis, and APOL3 overexpression markedly suppressed melanoma cell proliferation by reducing glucose uptake and lactate production in vitro. Mechanistically, STAT3 directly down-regulated APOL3 transcription. Swimming upregulated APOL3 by inactivating the IL-6R-STAT3 signaling axis in melanoma cells by inhibiting the secretion of IL-6 by M2 macrophages. As expected, IL-6 secreted by M2 macrophages promoted glycolysis in melanoma cells by reducing APOL3 expression. In summary, swimming inactivated the IL-6R/STAT3 signaling axis in melanoma cells by inhibiting the secretion of IL-6 by M2 macrophages, which could suppress the growth of melanoma in the body by upregulating APOL3 to inhibit glycolysis.

Early downmodulation of tumor glycolysis predicts response to fasting-mimicking diet in triple-negative breast cancer patients.

In preclinical experiments, cyclic fasting-mimicking diets (FMDs) showed broad anticancer effects in combination with chemotherapy. Among different tumor types, triple-negative breast cancer (TNBC) is exquisitely sensitive to FMD. However, the antitumor activity and efficacy of cyclic FMD in TNBC patients remain unclear. Here, we show that a severely calorie-restricted, triweekly, 5-day FMD regimen results in excellent pathologic complete response (pCR) rates (primary endpoint) and long-term clinical outcomes (secondary endpoints) when combined with preoperative chemotherapy in 30 patients with early-stage TNBC enrolled in the phase 2 trial BREAKFAST. Bulk and single-cell RNA sequencing analysis revealed that highly glycolytic cancer cells, myeloid cells, and pericytes from tumors achieving pCR undergo a significant, early downmodulation of pathways related to glycolysis and pyruvate metabolism. Our findings pave the wave for conducting larger clinical trials to investigate the efficacy of cyclic FMD in early-stage TNBC patients and to validate early changes of intratumor glycolysis as a predictor of clinical benefit from nutrient restriction. This study was registered at Clinicaltrials.gov (NCT04248998).

Engineered Biomimetic Cancer Cell Membrane Nanosystems Trigger Gas-Immunometabolic Therapy for Spinal-Metastasized Tumors.

Despite great progress in enhancing tumor immunogenicity, conventional gas therapy cannot effectively reverse the tumor immunosuppressive microenvironment (TIME), limiting immunotherapy. The development of therapeutic gases that are tumor microenvironment responsive and efficiently reverse the TIME for precisely targeted tumor gas-immunometabolic therapy remains a great challenge. In this study, a novel cancer cell membrane-encapsulated pH-responsive nitric oxide (NO)-releasing biomimetic nanosystem (MP@AL) is prepared. Lactate oxidase (Lox) in MP@AL consumed oxygen to promote the decomposition of lactate, a metabolic by-product of tumor glycolysis, and the generation of H2O2, while L-arginine (L-Arg) in MP@AL is oxidized by H2O2 to generate nitric oxide (NO). For one thing, NO led to mitochondrial dysfunction in tumor cells to reduce oxygen consumption and promote the efficiency of Lox in lactate decomposition, thus reversing lactate-induced TIME; for another, NO effectively triggered immunogenic cell death, activated anti-tumor immune response and long-term immune memory, and ensured a favorable effect in the synergistic interaction with PD-L1 antibody for inhibiting tumor growth and recurrence. Therefore, a novel gas-immunometabolic therapy dual closed-loop nanosystem for enhancing tumor immunogenicity and remodeling lactate-induced TIME is established. Overall, this work will provide new ideas for gas therapy to effectively remodel the TIME to enhance cancer immunotherapy.

TMET-39. DUAL TARGETING OF MAP KINASE SIGNALING AND METABOLISM IS A THERAPEUTIC VULNERABILITY IN PEDIATRIC DIFFUSE MIDLINE GLIOMAS

Abstract Metabolic reprogramming in pediatric diffuse midline glioma is driven by gene expression changes induced by the hallmark histone mutation H3K27M, which results in aberrantly permissive activation of oncogenic signaling pathways. Previous studies of diffuse midline glioma with altered H3K27 (DMG-H3K27a) have shown that the RAS pathway, specifically through its downstream kinase, extracellular-signal-related kinase 5 (ERK5), is critical for tumor growth. However, there remains a knowledge gap in identifying effectors of ERK signaling and their roles in DMG-H3K27a. Leveraging several patient multi-omic datasets, we identified a unique relationship between ERK5 and brain tumor glycolysis. We establish that ERK5 is a critical regulator of cell proliferation and glycolysis in DMG-H3K27a, where ERK5 knockdown leads to decreases in glycolysis and increases in mitochondrial metabolism. We demonstrate through loss of function and overexpression studies that ERK5 mediates glycolysis through regulation of glycolytic enzyme Phosphofructo-2-Kinase/Fructose-2,6-Biphosphatase 3 (PFKFB3). PFKFB3 is a protein that catalyzes the synthesis or degradation of fructose-2,6-bisphosphate (F2,6BP). Furthermore, we establish a novel mechanism, in which ERK5 mediates PFKFB3 expression via activation of MEF2A, an oncogenic transcription factor. DMG-H3K27a cells are sensitive to the loss or inhibition of PFKFB3 both in vitro and in orthotopic mouse models. However, monotherapy is ineffective in heterogenous diseases such as gliomas, including DMG-H3K27a. To combat this, we show multi-targeted therapy against the ERK5-PFKFB3 axis is synergistic in vitro and in vivo. Multi-targeted drug therapy against the ERK5-PFKFB3 axis, such as with small-molecule inhibitors, may represent a promising therapeutic approach in patients with pediatric diffuse midline glioma. Moreover, we have identified resistance to our dual therapy using several systems biology approaches, which we are currently investigating and validating. Collectively, our study defines a novel, targetable axis in DMG-H3K27a and highlights the importance of tumor cell metabolism in defining therapeutic vulnerabilities.

β-Ketoenamine covalent organic framework nanoplatform combined with immune checkpoint blockade via photodynamic immunotherapy inhibit glioblastoma progression

The synergistic approach of combining photodynamic immunotherapy with endogenous clearance of PD-L1 immune checkpoint blockade therapy holds promise for enhancing survival outcomes in glioblastoma (GBM) patients. The observed upregulation of O-GlcNAc glycolysis in tumors may contribute to the stabilization of endogenous PD-L1 protein, facilitating tumor immune evasion. This study presents a pH-adapted excited state intramolecular proton transfer (ESIPT)-isomerized β-ketoamide-based covalent organic framework (COF) nanoplatform (denoted as OT@COF-RVG). Temozolomide (TMZ) and OSMI-4 (O-GlcNAc transferase inhibitor) were integrated into COF cavities, then modified on the surface with polyethylene glycol and the rabies virus peptide RVG-29, showing potential for sensitizing TMZ chemotherapy and initiating photodynamic therapy (PDT). By inhibiting O-GlcNAc and promoting lysosomal degradation of PD-L1, OT@COF-RVG enhanced the effectiveness of immune checkpoint blockade (ICB) therapy. Additionally, treatment with OT@COF-RVG led to a notable elevation in reactive oxygen species (ROS) levels, thereby re-establishing an immunostimulatory state, inducing immunogenic cell death (ICD). In summary, our research unveiled a correlation between O-GlcNAc in GBM and the evasion of immune responses by tumors, while showcasing the potential of OT@COF-RVG in reshaping the immunosuppressive microenvironment of GBM and offering a more effective approach to immunotherapy in clinical settings.

UBR5 metabolically reprograms nasopharyngeal carcinoma cells to promote glycolysis and M2 polarization via SPLUNC1 signaling.

Nasopharyngeal carcinoma (NPC) is the most common cancer originating in nasopharynx. Metabolic reprogramming plays a critical role in tumor progression. Exploring mechanisms underlying metabolic reprogramming contributes to deeper understanding of NPC pathogenesis. Here, we found downregulation of RORA and SPLUNC1 in NPC, and RORA downregulation indicates poor prognosis. RORA binds to SPLUNC1 promoter to induce its transcription, and RORA overexpression inhibits cell proliferation and glycolysis by directly upregulating SPLUNC1. UBR5 inhibits RORA via promoting RORA ubiquitination and degradation, and UBR5 silencing represses proliferation and glycolysis in NPC. Additionally, METTL14, which is highly expressed in NPC, facilitates UBR5 mRNA stability by promoting its m6A modification through IGF2BP2. UBR5/RORA/SPLUNC1 axis facilitates M2 polarization by activating the GPR132 signaling. UBR5 silencing inhibits tumor growth, glycolysis and M2 polarization through RORA/SPLUNC1 signaling in mice. In conclusion, UBR5 promotes proliferation, glycolysis and M2 polarization by metabolically reprograming NPC cells through suppression of the RORA/SPLUNC1 signaling.

Photo-Thermally Controllable Tumor Metabolic Modulation to Assist T Cell Activation for Boosting Immunotherapy.

Glycolysis is crucial for tumor cell proliferation, supporting their energy needs and influencing the tumor microenvironment (TME). On one hand, increased lactate levels produced by glycolysis acidifies the TME, inhibiting T cell activity. On the other hand, glycolysis promotes the expression of PD-L1 through various mechanisms, facilitating immune evasion. Therefore, controlled modulation of glycolysis in tumor cells to subsequently improve the immune tumor microenvironment holds significant implications for clinical cancer treatment and immune regulation. To reverse the immunosuppressive microenvironment caused by tumor glycolysis and reduce tumor immune escape, we developed a photo-thermal-controlled precision drug delivery platform to regulate tumor metabolism and aid in the activation of T cells, thereby enhancing immunotherapy. First, hollow mesoporous Prussian blue (HPB) was prepared, and the glycolysis inhibitor 3-bromopyruvate (3-BrPA) was encapsulated within HPB using the phase-change material 1-tetradecanol, resulting in B/T-H. This product was then modified with tumor cell membranes to obtain a photo-thermal controllable regulator (B/T-H@Membrane, B/T-HM). Due to the excellent drug loading and photo-thermal properties of HPB, upon reaching the tumor, B/T-HM can rapidly heat under 808 nm irradiation, causing the 1-tetradecanol to transition to a liquid phase and release 3-BrPA, which effectively inhibits tumor glycolysis through the HK2 pathway, thereby reducing tumor cell proliferation, decreasing lactate production, and downregulating tumor PD-L1 expression. In synergy with photo-thermal and αPD-1, this photo-thermally controllable metabolic-immune therapy effectively activates T cells to eliminate tumor. In response to the changes in immune microenvironment caused by tumor metabolism, a photo-thermal precision-controlled drug delivery platform was successfully developed. This platform reshapes the tumor immunosuppressive microenvironment, providing a new approach for T cell-based tumor immunotherapy. It also opens new avenues for photo-thermal controllable metabolic-immune therapy.

USP28 promotes tumor progression and glycolysis by stabilizing PKM2/Hif1-α in cholangiocarcinoma.

Ubiquitination is one of the important modification of proteins which can be reversed by deubiquitinating enzymes (DUBs). Ubiquitin specific protease 28 (USP28) belongs to the deubiquitinase family, which plays a cancer-promoting function in many types of cancers such as pancreatic cancer and breast cancer. So far, the molecular function and significance of USP 28 in cholangiocarcinoma remain unclear. In this study, we evaluated the expression of USP28 using tissue microarray (TMA), reverse transcription polymerase chain reaction (qRT-PCR), and online databases. We investigated the effect of USP28 on the progression of CCA through in vitro and in vivo functional experiments. In addition, we explored downstream molecular pathways using Western blotting (WB), immunofluorescence (IF), and mass spectrometry techniques. Here, we found that cholangiocarcinoma tissue had higher USP 28 expression than normal bile duct tissue, and that high USP 28 levels were significantly associated with a malignant phenotype and poorer prognosis in cholangiocarcinoma patients. Both in vitro and in vivo, USP28 could mediate the deubiquitination of PKM2, thereby activating the downstream Hif1-α signaling pathway, promoting glycolysis and energy supply, and finally promoting tumor progression. In summary, USP28 activated downstream Hif1-α by reducing the ubiquitination level of PKM2, furthermore, promoting the level of glycolysis in CCA cells for tumor progression.

The CCR6-CCL20 Axis Promotes Regulatory T-cell Glycolysis and Immunosuppression in Tumors.

Regulatory T cells (Treg) are important players in the tumor microenvironment. However, the mechanisms behind their immunosuppressive effects are poorly understood. We found that CCR6-CCL20 activity in tumor-infiltrating Tregs is associated with greater glycolytic activity and ablation of Ccr6 reduced glycolysis and lactic acid production while increasing compensatory glutamine metabolism. Immunosuppressive activity toward CD8+ T cells was abrogated in Ccr6-/- Tregs due to reduction in activation-induced glycolysis. Furthermore, Ccr6-/- mice exhibited improved survival across multiple tumor models compared to wild-type mice and Treg and CD8+ T-cell depletion abrogated the improvement. In addition, Ccr6 ablation further promoted the efficacy of anti-PD-1 therapy in a preclinical glioma model. Follow-up knockdown of Ccl20 with siRNA also demonstrated improvement in antitumor efficacy. Our results unveil CCR6 as a marker and regulator of Treg-induced immunosuppression and identify approaches to target the metabolic determinants of Treg immunosuppressive activity.

Pterostilbene Induces Pyroptosis in Breast Cancer Cells through Pyruvate Kinase 2/Caspase-8/Gasdermin C Signaling Pathway.

The incidence and mortality of breast cancer increase year by year, and it is urgent to find high-efficiency and low-toxicity anti-cancer drugs. Pterostilbene (PTE) is a natural product with antitumor activity, but the specific antitumor mechanism is not very clear. Aerobic glycolysis is the main energy supply for cancer cells. Pyroptosis is an inflammatory, programmed cell death. The aim of this study was to investigate the effect of PTE on glycolysis and pyroptosis in EMT6 and 4T1 cells and the specific mechanism, and to elucidate the role of pyruvate kinase 2 (PKM2), a key enzyme in glycolysis, in the antitumor role of PTE. Our study suggested that PTE induced pyroptosis by inhibiting tumor glycolysis. PKM2 played an important role in both the inhibition of glycolysis and the induction of pyroptosis by PTE.

605. MITOCHONDRIAL METABOLISM IN UPPER GI ADENOCARCINOMA DETERMINES PATIENT SURVIVAL

Abstract Background Mitochondrial oxidative phosphorylation (OXPHOS) is responsible for meeting the vast majority of cellular energy demands. Ever since the description of aerobic glycolysis by Warburg in 1927, it has been recognised that cancers have dysfunctional metabolism. Clinically, this Warburg effect is the basis of FDG-PET imaging, increased FDG uptake represents increased tumour glycolysis and translates to worse upper GI adenocarcinoma outcomes. The cause of OXPHOS disruption in upper GI adenocarcinoma is poorly understood, its impact on potential therapeutic strategies is yet to be explored. This is particularly pertinent in upper GI adenocarcinomas as despite recent improvements, 5-year survival remains alarmingly low. Method Oesophageal and gastric adenocarcinoma samples collected in the UK from 175 patients (89 oesophageal adenocarcinoma, 86 gastric adenocarcinoma, 131 male, 44 female, median age=65, IQR=12) who underwent radical resection with curative intent between 1995 and 2009. Quantitative immunofluorescence were used to determine expressions of OXPHOS Complex I and IV at a single cell level. Patients were divided into high vs. low expressors of Complex I and IV using K-means clustering to allow for subsequent subgroup analysis. Result Survival analysis demonstrated significantly worse outcomes for low expressors as compared to high expressors of Complex I at 5 years post-op (5-year survival probability low expressors=0.440, 95%CI=0.358-0.539, high expressors=0.629, 95%CI=0.515-0.769, P-value=0.048). Similarly comparison of Complex IV expression also demonstrates disadvantageous survival for Complex IV low expressors (5-year survival probability low expressors=0.432, 95%CI=0.346-0.538, high expressors=0.603, 95%CI=0.499-0.729, P-value=0.042). The low expressors of Complex I and IV encompassed significantly more Stage III disease as per AJCC 7th edition. The low vs. high expression Complex I and IV groups are similarly matched for baseline patient characteristics. Conclusion These results demonstrate reduced capacity to carry out OXPHOS in oesophageal and gastric adenocarcinoma is characteristic of more advanced cancer and results in worse patient outcomes. Further work is needed to determine if OXPHOS status impacts on neo-adjuvant therapy response and how to exploit OXPHOS deficiency therapeutically in oesophageal and gastric adenocarcinomas. The limitations of this preliminary work include small sample size and tissue derived from historic patients over a long period of time, during which treatment and outcomes for upper GI cancer have significantly changed.

Acidity induces durable enhancement of Treg cell suppressive functions for tumor immune evasion

The microenvironment within solid tumors often becomes acidic due to various factors associated with abnormal metabolism and cellular activities, including increased lactate production as a result of dysregulated tumor glycolysis. Recently, we have identified multiple tumor microenvironment (TME) factors that potentiate regulatory T (Treg) cell function in evading anti-tumor immunosurveillance. Despite the strong correlation between lactate and acidity, the potential roles of acidity in intratumoral Treg cell adaptation and underlying molecular mechanisms have gone largely unstudied. In this study, we demonstrate that acidity significantly enhances immunosuppressive functions of nTreg cells, but not iTreg cells, without altering the expression of either FoxP3 or the cell surface receptors CD25, CTLA4, or GITR in these cells. Surprisingly, the addition of lactate, often considered a major contributor to increased acidity of the TME, completely abolished the acidity-induced enhancement of nTreg suppressive functions. Consistently, metabolic flux analyses showed elevated basal mitochondrial respiratory capacity and ATP-coupled respiration in acidity-treated nTreg cells without altering glycolytic capacity. Genome-wide transcriptome and metabolomics analyses revealed alterations in multiple metabolic pathways, particularly the one-carbon folate metabolism pathway, with reduced SAM, folate, and glutathione, in nTreg cells exposed to low pH conditions. Addition of a one-carbon metabolic contributor, formate, diminished the acidity-induced enhancement in nTreg cell suppressive functions, but neither SAM nor glutathione could reverse the phenotype. Remarkably, in vitro transient treatment of nTreg cells resulted in sustained enhancement of their functions, as evidenced by more vigorous tumor growth observed in mice adoptively receiving acidity-treated nTreg cells. Further analysis of intratumoral infiltrated T cells confirmed a significant reduction in CD8+ T cell frequency and their granzyme B production. In summary, our study elucidates how acidity-mediated metabolic reprogramming leads to sustained Treg-mediated tumor immune evasion.

ALDH1A1 promotes immune escape of tumor cells through ZBTB7B-glycolysis pathway

The primary impediment to the success of immunotherapy lies in the immune evasion orchestrated by tumors, contributing to the suboptimal overall response rates observed. Despite this recognition, the intricacies of the underlying mechanisms remain incompletely understood. Through preliminary detection of clinical patient tissues, we have found that ALDH1A1 was a key gene for the prognosis of cancer patients and tumor glycolysis. In vitro experiments and tumor formation in nude mice suggested that targeting ALDH1A1 could inhibit tumor growth. Through further analysis of xenograft tumor models in immune-normal mice and flow cytometry, we found that deficiency in ALDH1A1 could promote immune system suppression of tumors in vivo. Specifically, RNA-seq analysis, combined with qPCR and western blot, identified the transcription factor ZBTB7B as downstream of ALDH1A1. The binding sites of the transcription factor ZBTB7B on the LDHA promoter region, which is responsible for regulating the rate-limiting enzyme gene LDHA in glycolysis, were determined using luciferase reporter gene detection and Chip-qPCR, respectively. In addition, the increased SUMOylation of ZBTB7B stabilized its transcriptional activity. Further in vivo and in vitro experiments confirmed that the combination of targeting ALDH1A1 and ZBTB7B with immune checkpoint inhibitors could synergistically inhibit tumors in vivo. Finally, after conducting additional verification of patient tissue and clinical data, we have confirmed the potential translational value of targeting ALDH1A1 and ZBTB7B for tumor immunotherapy. These results emphasize the potential translational significance of targeting ALDH1A1 and ZBTB7B in the realm of tumor immunotherapy. The convergence of ALDH1A1 inhibition and immune checkpoint blockade, particularly with PD-L1/PD-1 mAb, presents a compelling avenue for curtailing tumor immune escape.

Pharmacological targets of SGLT2 inhibition on prostate cancer mediated by circulating metabolites: a drug-target Mendelian randomization study.

The relationship between sodium-glucose cotransporter 2 (SGLT2) inhibitors and prostate cancer is still unknown. Although these inhibitors can influence tumor glycolysis, the underlying mechanism requires further exploration. A two-sample two-step MR was used to determine 1) causal effects of SGLT2 inhibition on prostate cancer; 2) causal effects of 1,400 circulating metabolites or metabolite ratios on prostate cancer; and 3) mediation effects of these circulating metabolites. Genetic proxies for SGLT2 inhibition were identified as variants in the SLC5A2 gene and glycated hemoglobin level (HbA1c). Additionally, positive control analysis on type 2 diabetes mellitus (T2DM) was conducted to test the selection of genetic proxies. Phenome Wide Association Study (PheWAS) and MR-PheWAS analysis were used to explore potential treatable diseases and adverse outcomes of SGLT2 inhibitors. Genetically predicted SGLT2 inhibition (per 1 SD decrement in HbA1c) was associated with reduced risk of T2DM [odds ratio (OR) = 0.66 (95% CI 0.53, 0.82), P = 1.57 × 10-4]; prostate cancer [0.34 (0.23, 0.49), P = 2.21 × 10-8] and prostate-specific antigen [0.26 (0.08, 0.81), P = 2.07 × 10-2]. The effect of SGLT2 inhibition on prostate cancer was mediated by uridine level, with a mediated proportion of 9.34% of the total effect. In MR-PheWAS, 65 traits were found to be associated with SLGT2 inhibitors (P < 1.78 × 10-5), and among them, 13 were related to diabetes. Our study suggested that SGLT2 inhibition could lower prostate cancer risk through uridine mediation. More mechanistic and clinical research is necessary to explore how uridine mediates the link between SGLT2 inhibition and prostate cancer.

The combined treatment with ketogenic diet and metformin slows tumor growth in two mouse models of triple negative breast cancer

BackgroundMany tumors contain hypoxic microenvironments caused by inefficient tumor vascularization. Hypoxic tumors have been shown to resist conventional cancer therapies. Hypoxic cancer cells rely on glucose to meet their energetic and anabolic needs to fuel uncontrolled proliferation and metastasis. This glucose dependency is linked to a metabolic shift in response to hypoxic conditions.MethodsTo leverage the glucose dependency of hypoxic tumor cells, we assessed the effects of a mild reduction in systemic glucose by controlling both dietary carbohydrates with a ketogenic diet and endogenous glucose production by using metformin on two mouse models of triple-negative breast cancer (TNBC).ResultsHere, we showed that animals with TNBC treated with the combination regimen of ketogenic diet and metformin (a) had their tumor burden lowered by two-thirds, (b) displayed 38% slower tumor growth, and (c) showed 36% longer latency, compared to the animals treated with a ketogenic diet or metformin alone. As a result, lowering systemic glucose by this combined dietary and pharmacologic approach improved overall survival in our mouse TNBC models by 31 days, approximately equivalent to 3 years of life extension in human terms.ConclusionThis preclinical study demonstrates that reducing systemic glucose by combining a ketogenic diet and metformin significantly inhibits tumor proliferation and increases overall survival. Our findings suggest a possible treatment for a broad range of hypoxic and glycolytic tumor types that can augment existing treatment options to improve patient outcomes.

The regulatory roles and clinical significance of glycolysis in tumor.

Metabolic reprogramming has been demonstrated to have a significant impact on the biological behaviors of tumor cells, among which glycolysis is an important form. Recent research has revealed that the heightened glycolysis levels, the abnormal expression of glycolytic enzymes, and the accumulation of glycolytic products could regulate the growth, proliferation, invasion, and metastasis of tumor cells and provide a favorable microenvironment for tumor development and progression. Based on the distinctive glycolytic characteristics of tumor cells, novel imaging tests have been developed to evaluate tumor proliferation and metastasis. In addition, glycolytic enzymes have been found to serve as promising biomarkers in tumor, which could provide assistance in the early diagnosis and prognostic assessment of tumor patients. Numerous glycolytic enzymes have been identified as potential therapeutic targets for tumor treatment, and various small molecule inhibitors targeting glycolytic enzymes have been developed to inhibit tumor development and some of them are already applied in the clinic. In this review, we systematically summarized recent advances of the regulatory roles of glycolysis in tumor progression and highlighted the potential clinical significance of glycolytic enzymes and products as novel biomarkers and therapeutic targets in tumor treatment.

Hypoxia within tumor microenvironment characterizes distinct genomic patterns and aids molecular subtyping for guiding individualized immunotherapy

Assessing the hypoxic status within the tumor microenvironment (TME) is crucial for its significant clinical relevance in evaluating drug resistance and tailoring individualized strategies. In this study, we proposed a robust pan-cancer hypoxic quantification method utilizing multiple public databases, diverse bioinformatics, and statistical methods. All tumor samples were classified into four subtypes: non-hypoxic/TMEhigh (C1), hypoxic/TMEhigh (C2), non-hypoxic/TMElow (C3), and hypoxic/TMElow (C4). We systematically analyzed multi-omics data and single-cell RNA-sequencing (scRNA-seq) data to reveal distinct immune landscape patterns and genomic characteristics among the four subtypes across pan-cancer. Furthermore, we employed multiple machine learning approaches to construct a hypoxic-TME model to enhance the predictive accuracy of immunotherapy response. Additionally, drug repositioning was implemented for cancer patients predicted as non-responders to immunotherapy. A pan-cancer analysis identified PDK1 as a hub gene linking tumor hypoxia, glycolysis, and immunotherapy resistance. In vivo experimental validation further confirmed that targeting PDK1 could improve the response to immunotherapy. Overall, our study may offer valuable insights for integrating hypoxic-TME classification into tumor staging and providing personalized strategies for cancer patients.

Effect of PLCE1-driven aerobic glycolysis through ENO1 modulation on immune evasion in esophageal squamous cell carcinoma (ESCC).

e16016 Background: Our prior investigations have demonstrated that PLCE1 actively promotes tumorigenesis, angiogenesis, and cell cycle progression in ESCC. However, the precise role of PLCE1 in glycolysis and its influence on the tumor immune microenvironment (TIME) remain elusive. Methods: To elucidate potential pathways regulated by PLCE1, we applied Affymetrix GeneChip, Affymetrix ClariomD Array, and IP-MS techniques to identify molecules interacting with PLCE1. Subsequently, we validated the involement of PLCE1 in glycolysis through assessments of glycolytic product production in both in vivo and in vitro assays. The underlying mechanisms by which PLCE1 influences glycolysis were further probed through a combination of IP assays, tumor growth experiments, and ubiquitination assays. Next, we conducted multi-color immunofluorescence staining to examine the infiltration of immune cells in human ESCC tissues. We utilized a transgenic PLCE1-/- C57BL/6 mice model to investigate the immune cell distribution in TIME. Results: PLCE1 emerges as a pivotal regulator in glycolytic processes within ESCC cell lines. Knockdown of PLCE1 instigates a notable attenuation of glycolysis, achieved through the modulation of ENO1 expression, a key enzyme in glycolysis. This effect was also observed in vivo. We have elucidated a novel pathway in which PLCE1 orchestrates a reduction in the expression of FBXW7, an E3 ubiquitin ligase, thereby attenuating FBXW7-mediated ubiquitination of ENO1 and fostering ENO1 stability. Based on mutations identified through sequencing of ESCC tissue and drawing from previous studies, we have pinpointed the specific interacting sites between FBXW7 and ENO1. Substrate phosphorylation is necessary for the recognition of FBXW7. We unveil a mechanism wherein PLCE1 interacts with CDK2 to augment ENO1 phosphorylation, potentiating FBXW7 recognition. Nonetheless, CDK2-mediated ENO1 phosphorylation fails to elicit FBXW7-mediated ubiquitination due to limited FBXW7 expression in ESCC. Elevated tumor glycolysis induced by PLCE1 via ENO1 engenders heightened lactate production, thereby dampening cytokine production and CD8+ T cell activation. In human ESCC tissues, a diminished CD8+ T cell population is observed proximal to PLCE1+ENO1+ tumor cells, concomitant with an augmented accumulation of exhausted CD8+ PD1+ T cells in their vicinity. In an ESCC murine model, a more robust infiltration and cytokine production, coupled with diminished PD-1 expression on both CD4+ and CD8+ T cells, is noted in the PLCE1-/- genotype. This effect was particularly prominent upon ENO1 inhibitor administration. Conclusions: Our investigation elucidates that PLCE1 orchestrates the glycolytic pathway in ESCC by upregulating the expression of ENO1, consequently hindering the infiltration and activation of CD8+ T cells, thus fostering an immunosuppressive TIME.

The tumor-intrinsic role of the m6A reader YTHDF2 in regulating immune evasion.

Tumors evade attacks from the immune system through various mechanisms. Here, we identify a component of tumor immune evasion mediated by YTH domain-containing family protein 2 (YTHDF2), a reader protein that usually destabilizes m6A-modified mRNA. Loss of tumoral YTHDF2 inhibits tumor growth and prolongs survival in immunocompetent tumor models. Mechanistically, tumoral YTHDF2 deficiency promotes the recruitment of macrophages via CX3CL1 and enhances mitochondrial respiration of CD8+ T cells by impairing tumor glycolysis metabolism. Tumoral YTHDF2 deficiency promotes inflammatory macrophage polarization and antigen presentation in the presence of IFN-γ. In addition, IFN-γ induces autophagic degradation of tumoral YTHDF2, thereby sensitizing tumor cells to CD8+ T cell-mediated cytotoxicity. Last, we identified a small molecule compound that preferentially induces YTHDF2 degradation, which shows a potent antitumor effect alone but a better effect when combined with anti-PD-L1 or anti-PD-1 antibodies. Collectively, YTHDF2 appears to be a tumor-intrinsic regulator that orchestrates immune evasion, representing a promising target for enhancing cancer immunotherapy.