Mechanical regulation of mitochondrial morphodynamics in cancer cells by extracellular microenvironment

Recently, it has been recognized that physical abnormalities (e.g. elevated solid stress, elevated interstitial fluid pressure, increased stiffness) are associated with tumor progression and development. Additionally, these mechanical forces originating from tumor cell environment through mechanotransduction pathways can affect metabolism. On the other hand, mitochondria are well-known as bioenergetic, biosynthetic, and signaling organelles crucial for sensing stress and facilitating cellular adaptation to the environment and physical stimuli. Disruptions in mitochondrial dynamics and function have been found to play a role in the initiation and advancement of cancer. Consequently, it is logical to hypothesize that mitochondria dynamics subjected to physical cues may play a pivotal role in mediating tumorigenesis. Recently mitochondrial biogenesis and turnover, fission and fusion dynamics was linked to mechanotransduction in cancer. However, how cancer cell mechanics and mitochondria functions are connected, still remain poorly understood. Here, we discuss recent studies that link mechanical stimuli exerted by the tumor cell environment and mitochondria dynamics and functions. This interplay between mechanics and mitochondria functions may shed light on how mitochondria regulate tumorigenesis.

Crosstalk between metabolism and cell death in tumorigenesis

It is generally recognized that tumor cells proliferate more rapidly than normal cells. Due to such an abnormally rapid proliferation rate, cancer cells constantly encounter the limits of insufficient oxygen and nutrient supplies. To satisfy their growth needs and resist adverse environmental events, tumor cells modify the metabolic pathways to produce both extra energies and substances required for rapid growth. Realizing the metabolic characters special for tumor cells will be helpful for eliminating them during therapy. Cell death is a hot topic of long-term study and targeting cell death is one of the most effective ways to repress tumor growth. Many studies have successfully demonstrated that metabolism is inextricably linked to cell death of cancer cells. Here we summarize the recently identified metabolic characters that specifically impact on different types of cell deaths and discuss their roles in tumorigenesis.

Tumor metabolic crosstalk and immunotherapy

Tumor cells must resist the host's immune system while maintaining growth under harsh conditions of acidity and hypoxia, which indicates that tumors are more robust than normal tissue. Immunotherapeutic agents have little effect on solid tumors, mostly because of the tumor density and the difficulty of penetrating deeply into the tissue to achieve the theoretical therapeutic effect. Various therapeutic strategies targeting the tumor microenvironment (TME) have been developed. Immunometabolic disorders play a dominant role in treatment resistance at both the TME and host levels. Understanding immunometabolic factors and their treatment potential may be a way forward for tumor immunotherapy. Here, we summarize the metabolism of substances that affect tumor progression, the crosstalk between the TME and immunosuppression, and some potential tumor-site targets. We also summarize the progress and challenges of tumor immunotherapy.

DHCR7 promotes lymph node metastasis in cervical cancer through cholesterol reprogramming-mediated activation of the KANK4/PI3K/AKT axis and VEGF-C secretion

Cervical cancer (CC) patients with lymph node metastasis (LNM) have a poor prognosis. However, the molecular mechanism of LNM in CC is unclear, and there is no effective clinical treatment. Here, we found that 7-dehydrocholesterol reductase (DHCR7), an enzyme that catalyzes the last step of cholesterol synthesis, was upregulated in CC and closely related to LNM. Gain-of-function and loss-of-function experiments proved that DHCR7 promoted the invasion ability of CC cells and lymphangiogenesis in vitro and induced LNM in vivo. The LNM-promoting effect of DHCR7 was partly mediated by upregulating KN motif and ankyrin repeat domains 4 (KANK4) expression and subsequently activating the PI3K/AKT signaling pathway. Alternatively, DHCR7 promoted the secretion of vascular endothelial growth factor-C (VEGF-C), and thereby lymphangiogenesis. Interestingly, cholesterol reprogramming was needed for the DHCR7-mediated promotion of activation of the KANK4/PI3K/AKT axis, VEGF-C secretion, and subsequent LNM. Importantly, treatment with the DHCR7 inhibitors AY9944 and tamoxifen (TAM) significantly inhibited LNM of CC, suggesting the clinical application potential of DHCR7 inhibitors in CC. Collectively, our results uncover a novel molecular mechanism of LNM in CC and identify DHCR7 as a new potential therapeutic target.

The radiation- and chemo-sensitizing capacity of diclofenac can be predicted by a decreased lactate metabolism and stress response

BACKGROUND

An enhanced aerobic glycolysis ("Warburg effect") associated with an increase in lactic acid in the tumor microenvironment contributes to tumor aggressiveness and resistance to radiation and chemotherapy. We investigated the radiation- and chemo-sensitizing effects of the nonsteroidal anti-inflammatory drug (NSAID) diclofenac in different cancer cell types.

METHODS

The effects of a non-lethal concentration of diclofenac was investigated on c-MYC and Lactate Dehydrogenase (LDH) protein expression/activity and the Heat shock Protein (HSP)/stress response in human colorectal (LS174T, LoVo), lung (A549), breast (MDA-MB-231) and pancreatic (COLO357) carcinoma cells. Radiation- and chemo-sensitization of diclofenac was determined using clonogenic cell survival assays and a murine xenograft tumor model.

RESULTS

A non-lethal concentration of diclofenac decreases c-MYC protein expression and LDH activity, reduces cytosolic Heat Shock Factor 1 (HSF1), Hsp70 and Hsp27 levels and membrane Hsp70 positivity in LS174T and LoVo colorectal cancer cells, but not in A549 lung carcinoma cells, MDA-MB-231 breast cancer cells and COLO357 pancreatic adenocarcinoma cells. The impaired lactate metabolism and stress response in diclofenac-sensitive colorectal cancer cells was associated with a significantly increased sensitivity to radiation and 5Fluorouracil in vitro, and in a human colorectal cancer xenograft mouse model diclofenac causes radiosensitization.

CONCLUSION

These findings suggest that a decrease in the LDH activity and/or stress response upon diclofenac treatment predicts its radiation/chemo-sensitizing capacity.

Prognostic features of the tumor microenvironment in high-grade serous ovarian cancer and dietary immunomodulation

High-grade serous ovarian cancer (HGSOC) is a particularly lethal malignancy that is prognostically influenced by the immune profile of the tumor microenvironment (TME). TME immune profiles have been sub-categorized according to features associated with both survival outcomes as well as response to systemic therapies. Five suggested immune phenotypes have been described and correlated with overall survival outcomes. Phenotypes associated with shorter overall survival rates appear to have prominent immunosuppressive features within their TME. The opportunity to triage patients according to their prognostic TME profile might allow selection of individual patients with poor prognostic features who could most benefit from innovative immunomodulatory treatment strategies. Two potential strategies to indirectly manipulate the TME (and oncologic outcomes) are alteration of the gut microbiome composition and alteration of TME metabolism through dietary interventions. Experimental dietary modifications in humans designed for influencing cancer outcomes are only beginning to be studied in a prospective fashion. Herein we summarize prognostic TME features in HGSOC and potential opportunities for immunomodulation via dietary and gut microbial interventions.

Oncometabolite lactate enhances breast cancer progression by orchestrating histone lactylation-dependent c-Myc expression

Due to the enhanced glycolytic rate, cancer cells generate lactate copiously, subsequently promoting the lactylation of histones. While previous studies have explored the impact of histone lactylation in modulating gene expression, the precise role of this epigenetic modification in regulating oncogenes is largely unchartered. In this study, using breast cancer cell lines and their mutants exhibiting lactate-deficient metabolome, we have identified that an enhanced rate of aerobic glycolysis supports c-Myc expression via promoter-level histone lactylation. Interestingly, c-Myc further transcriptionally upregulates serine/arginine splicing factor 10 (SRSF10) to drive alternative splicing of MDM4 and Bcl-x in breast cancer cells. Moreover, our results reveal that restricting the activity of critical glycolytic enzymes affects the c-Myc-SRSF10 axis to subside the proliferation of breast cancer cells. Our findings provide novel insights into the mechanisms by which aerobic glycolysis influences alternative splicing processes that collectively contribute to breast tumorigenesis. Furthermore, we also envisage that chemotherapeutic interventions attenuating glycolytic rate can restrict breast cancer progression by impeding the c-Myc-SRSF10 axis.

[18F]FDG PET/CT for predicting triple-negative breast cancer outcomes after neoadjuvant chemotherapy with or without pembrolizumab

PURPOSE

To determine if pretreatment [18F]FDG PET/CT could contribute to predicting complete pathological complete response (pCR) in patients with early-stage triple-negative breast cancer (TNBC) undergoing neoadjuvant chemotherapy with or without pembrolizumab.

METHODS

In this retrospective bicentric study, we included TNBC patients who underwent [18F]FDG PET/CT before neoadjuvant chemotherapy (NAC) or chemo-immunotherapy (NACI) between March 2017 and August 2022. Clinical, biological, and pathological data were collected. Tumor SUVmax and total metabolic tumor volume (TMTV) were measured from the PET images. Cut-off values were determined using ROC curves and a multivariable model was developed using logistic regression to predict pCR.

RESULTS

N = 191 patients were included. pCR rates were 53 and 70% in patients treated with NAC (N = 91) and NACI (N = 100), respectively (p < 0.01). In univariable analysis, high Ki67, high tumor SUVmax (> 12.3), and low TMTV (≤ 3.0 cm3) were predictors of pCR in the NAC cohort while tumor staging classification (< T3), BRCA1/2 germline mutation, high tumor SUVmax (> 17.2), and low TMTV (≤ 7.3 cm3) correlated with pCR in the NACI cohort. In multivariable analysis, only high tumor SUVmax (NAC: OR 8.8, p < 0.01; NACI: OR 3.7, p = 0.02) and low TMTV (NAC: OR 6.6, p < 0.01; NACI: OR 3.5, p = 0.03) were independent factors for pCR in both cohorts, albeit at different thresholds.

CONCLUSION

High tumor metabolism (SUVmax) and low tumor burden (TMTV) could predict pCR after NAC regardless of the addition of pembrolizumab. Further studies are warranted to validate such findings and determine how these biomarkers could be used to guide neoadjuvant therapy in TNBC patients.

Research progress of hyperthermia in tumor therapy by influencing metabolic reprogramming of tumor cells

Cellular metabolic reprogramming is an important feature of malignant tumors. Metabolic reprogramming causes changes in the levels or types of specific metabolites inside and outside the cell, which affects tumorigenesis and progression by influencing gene expression, the cellular state, and the tumor microenvironment. During tumorigenesis, a series of changes in the glucose metabolism, fatty acid metabolism, amino acid metabolism, and cholesterol metabolism of tumor cells occur, which are involved in the process of cellular carcinogenesis and constitute part of the underlying mechanisms of tumor formation. Hyperthermia, as one of the main therapeutic tools for malignant tumors, has obvious effects on tumor cell metabolism. In this paper, we will combine the latest research progress in the field of cellular metabolic reprogramming and focus on the current experimental research and clinical treatment of hyperthermia in cellular metabolic reprogramming to discuss the feasibility of cellular metabolic reprogramming-related mechanisms guiding hyperthermia in malignant tumor treatment, so as to provide more ideas for hyperthermia to treat malignant tumors through the direction of cellular metabolic reprogramming.

Genomic and transcriptomic profiling indicates the prognosis significance of mutational signature for TMB-high subtype in Chinese patients with gastric cancer

INTRODUCTION

Gastric cancer (GC)is the third leading cause of cancer-related deaths in China and immunotherapy emerging as a revolutionary treatment for GC recently. Tumor mutational burden (TMB) is a predictive biomarker of immunotherapy in multiple cancers. However, the prognostic significance and subtype of TMB in GC is not fully understood.

OBJECTIVES

This study aims to evaluate the prognostic value of TMB in Chinese GC and further classify TMB-high GC (GCTMB-H) patients combing with mutational signatures.

METHODS

Genomic profiling of 435 cancer-gene panel was performed using 206 GC samples from Chinese people. Actionable genetic alterations were compared across all the samples to generate actionable subtyping. The prognostic value of TMB in Chinese GC was evaluated. Mutational signatures were analyzed on TMB-H subtype to stratify the prognosis of TMB. Transcriptomic analysis was applied to compare the distributed immunocytes among different subtypes.

RESULTS

88.3% (182/206) of GC samples had at least one mutation, while 45.1% (93/206) had at least one somatic copy number alteration (SCNA). 29.6% (61/206) of GC samples were TMB-H, including 13 MSI-H and 48 MSS tumors. According to distinct genetic alteration profiles of 69 actionable genes, we classified GC samples into eight molecular subtypes, including TMB-H, ERBB2 amplified, ATM mutated, BRCA2 mutated, CDKN2A/B deleted, PI3KCA mutated, KRAS mutated, and less-mutated subtype. TMB-H subtype presented a remarkable immune-activated phenotype as determined by transcriptomic analysis that was further validated in the TCGA GC cohort. GCTMB-H patients exhibited significantly better survival (P = 0.047). But Signature 1-high GCTMB-H patients had relatively worse prognosis (P = 0.0209, HR = 2.571) than Signature 1-low GCTMB-H patients from Chinese GC cohort, also validated in TCGA GC cohort, presenting highly activated carbohydrate, fatty acid or lipid metabolism.

CONCLUSION

The Signature 1-high GCTMB-H could be a marker of poor prognosis and is associated with metabolism disorder.

Modulation of AMPK Significantly Alters Uveal Melanoma Tumor Cell Viability

INTRODUCTION

Uveal melanoma (UM) responds poorly to targeted therapies or immune checkpoint inhibitors. Adenosine monophosphate-activated protein kinase (AMPK) is a pivotal serine/threonine protein kinase that coordinates vital processes such as cell growth. Targeting AMPK pathway, which represents a critical mechanism mediating the survival of UM cells, may prove to be a novel treatment strategy for UM. We aimed to demonstrate the effects of AMPK modulation on UM cells.

METHODS

In silico analyses were performed to compare UM and normal melanocyte cells via Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA). The effects of AMPK modulation on cell viability and proliferation in UM cell lines with different molecular profiles (i.e., 92-1, MP46, OMM2.5, and Mel270) were investigated via XTT cell viability and proliferation assays after treating the cells with varying concentrations of A-769662 (AMPK activator) or dorsomorphin (AMPK inhibitor).

RESULTS

KEGG/GSEA studies demonstrated that genes implicated in the AMPK signaling pathway were differentially regulated in UM. Gene sets comprising genes involved in AMPK signaling and genes involved in energy-dependent regulation of mammalian target of rapamycin by liver kinase B1-AMPK were downregulated in UM. We observed gradual decreases in the numbers of viable UM cells as the concentration of A-769662 treatment increased. All UM cells demonstrated statistically significant decreases in cell viability when treated with 200 µm A-769662. Moreover, the effects of AMPK inhibition on UM cells were potent, since low doses of dorsomorphin treatment resulted in significant decreases in viabilities of UM cells. The half maximal inhibitory concentration (IC50) values confirmed the potency of dorsomorphin treatment against UM in vitro.

CONCLUSION

AMPK may act like a friend or a foe in cancer depending on the context. As such, the current study contributes to the literature in determining the effects of therapeutic strategies targeting AMPK in several UM cells. We propose a new perspective in the treatment of UM. Targeting AMPK pathway may open up new avenues in developing novel therapeutic approaches to improve overall survival in UM.

Discovering metabolic vulnerability using spatially resolved metabolomics for antitumor small molecule-drug conjugates development as a precise cancer therapy strategy

Against tumor-dependent metabolic vulnerability is an attractive strategy for tumor-targeted therapy. However, metabolic inhibitors are limited by the drug resistance of cancerous cells due to their metabolic plasticity and heterogeneity. Herein, choline metabolism was discovered by spatially resolved metabolomics analysis as metabolic vulnerability which is highly active in different cancer types, and a choline-modified strategy for small molecule-drug conjugates (SMDCs) design was developed to fool tumor cells into indiscriminately taking in choline-modified chemotherapy drugs for targeted cancer therapy, instead of directly inhibiting choline metabolism. As a proof-of-concept, choline-modified SMDCs were designed, screened, and investigated for their druggability in vitro and in vivo. This strategy improved tumor targeting, preserved tumor inhibition and reduced toxicity of paclitaxel, through targeted drug delivery to tumor by highly expressed choline transporters, and site-specific release by carboxylesterase. This study expands the strategy of targeting metabolic vulnerability and provides new ideas of developing SMDCs for precise cancer therapy.

Exosomal circRNA: emerging insights into cancer progression and clinical application potential

Exosomal circRNA serves a novel genetic information molecule, facilitating communication between tumor cells and microenvironmental cells, such as immune cells, fibroblasts, and other components, thereby regulating critical aspects of cancer progression including immune escape, tumor angiogenesis, metabolism, drug resistance, proliferation and metastasis. Interestingly, microenvironment cells have new findings in influencing tumor progression and immune escape mediated by the release of exosomal circRNA. Given the intrinsic stability, abundance, and broad distribution of exosomal circRNAs, they represent excellent diagnostic and prognostic biomarkers for liquid biopsy. Moreover, artificially synthesized circRNAs may open up new possibilities for cancer therapy, potentially bolstered by nanoparticles or plant exosome delivery strategies. In this review, we summarize the functions and underlying mechanisms of tumor cell and non-tumor cell-derived exosomal circRNAs in cancer progression, with a special focus on their roles in tumor immunity and metabolism. Finally, we examine the potential application of exosomal circRNAs as diagnostic biomarkers and therapeutic targets, highlighting their promise for clinical use.

The Warburg effect: a score for many instruments in the concert of cancer and cancer niche cells

Although Warburg's discovery of intensive glucose uptake by tumors, followed by lactate fermentation in oxygen presence of oxygen was made a century ago, it is still an area of intense research and development of new hypotheses that, layer by layer, unravel the complexities of neoplastic transformation. This seemingly simple metabolic reprogramming of cancer cells reveals an intriguing, multi-faceted nature that may link various phenomena including cell signaling, cell proliferation, ROS generation, energy supply, macromolecules synthesis/biosynthetic precursor supply, immunosuppression, or cooperation of cancerous cells with cancer-associated fibroblasts (CAFs), known as reversed Warburg effect. According to the current perception of the causes and consequences of the Warburg effect, PI3K/Akt/mTOR are the main signaling pathways that, in concert with the transcription factors HIF-1, p53, and c-Myc, modulate the activity/expression of key regulatory enzymes, including PKM2, and PDK1 to tune in the most optimal metabolic setting for the cancer cell. This in turn secures adequate levels of biosynthetic precursors, NADPH, NAD⁺, and rapid ATP production to meet the increased demands of intensively proliferating tumor cells. The end-product of "aerobic glycolysis", lactate, an oncometabolite, may provide fuel to neighboring cancer cells, and facilitate metastasis and immunosuppression together enabling cancer progression. The importance and possible applicability of the presented issue are best illustrated by numerous trials with various agents targeting the Warburg effect, constituting a promising strategy in future anti-cancer regimens. In this review, we present the key aspects of this multifactorial phenomenon, depicting the mechanisms and benefits behind the Warburg effect, and also pointing to selected aspects in the field of anticancer therapy.

Colorectal cancer liver metastasis: genomic evolution and crosstalk with the liver microenvironment

Colorectal cancer (CRC) patients frequently develop liver metastases, which are the major cause of cancer-related mortality. The molecular basis and management of colorectal liver metastases (CRLMs) remain a challenging clinical issue. Recent genomic evidence has demonstrated the liver tropism of CRC and the presence of a stricter evolutionary bottleneck in the liver as a target organ compared to lymph nodes. This bottleneck challenging CRC cells in the liver is organ-specific and requires adaptation not only at the genetic level, but also at the phenotypic level to crosstalk with the hepatic microenvironment. Here, we highlight the emerging evidence on the clonal evolution of CRLM and review recent insights into the molecular mechanisms orchestrating the bidirectional interactions between metastatic CRC cells and the unique liver microenvironment.

Metabolic heterogeneity in TNBCs: A potential determinant of therapeutic efficacy of 2-deoxyglucose and metformin combinatory therapy

Breast cancers (BCs) remain the leading cause of cancer-related deaths among women worldwide. Among the different types of BCs, treating the highly aggressive, invasive, and metastatic triple-negative BCs (TNBCs) that do not respond to hormonal/human epidermal growth factor receptor 2 (HER2) targeted interventions since they lack ER/PR/HER2 receptors remains challenging. While almost all BCs depend on glucose metabolism for their proliferation and survival, studies indicate that TNBCs are highly dependent on glucose metabolism compared to non-TNBC malignancies. Hence, limiting/inhibiting glucose metabolism in TNBCs should curb cell proliferation and tumor growth. Previous reports, including ours, have shown the efficacy of metformin, the most widely prescribed antidiabetic drug, in reducing cell proliferation and growth in MDA-MB-231 and MDA-MB-468 TNBC cells. In the current study, we investigated and compared the anticancer effects of either metformin (2 mM) in glucose-starved or 2-deoxyglucose (10 mM; glycolytic inhibitor; 2DG) exposed MDA-MB-231 and MDA-MB-468 TNBC cells. Assays for cell proliferation, rate of glycolysis, cell viability, and cell-cycle analysis were performed. The status of proteins of the mTOR pathway was assessed by Western blot analysis. Metformin treatment in glucose-starved and 2DG (10 mM) exposed TNBC cells inhibited the mTOR pathway compared to non-treated glucose-starved cells or 2DG/metformin alone treated controls. Cell proliferation is also significantly reduced under these combination treatment conditions. The results indicate that combining a glycolytic inhibitor and metformin could prove an efficient therapeutic approach for treating TNBCs, albeit the efficacy of the combination treatment may depend on metabolic heterogeneity across various subtypes of TNBCs.

JMJD5 inhibits lung cancer progression by regulating glucose metabolism through the p53/TIGAR pathway

Metabolic reprogramming is considered one of the main driving forces for tumor progression, providing energy and substrates of biosynthesis to support rapid neoplastic proliferation. Particularly, the tumor suppressor protein p53 was shown to revert the Warburg effect and play complex roles in regulating glucose metabolism. Jumonji C domain-containing protein 5 (JMJD5) has previously been reported as a negative regulator of p53. However, the role of JMJD5 in p53-mediated metabolic reprogramming remains elusive. Here, we discovered that knockdown of JMJD5 significantly enhances TIGAR expression in p53 wild-type non-small cell lung cancer (NSCLC) cells, which could further suppress glycolysis and promote the pentose phosphate pathway. Besides, JMJD5 knockdown promotes the NSCLC cell proliferation in vitro and xenograft tumor growth in vivo, while silencing TIGAR can abolish this effect. Low JMJD5 expression levels are associated with elevated TIGAR levels and correlates with poor prognosis in lung cancer patients. Taken together, our findings suggest that JMJD5 is a key regulator of tumor glucose metabolism by targeting the p53/TIGAR metabolic pathway.

Regulation of metabolism in pancreatic ductal adenocarcinoma via nanotechnology-enabled strategies

Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal malignancy with insidious onset and early distal metastasis. Metabolic reprogramming, the autonomous changes in cellular bioenergetics driven by aberrant genetic events and crosstalk between cancer and non-cancer cells in the desmoplastic microenvironment, is pivotal for the rapid progression of PDAC. As an attractive therapeutic target, nucleoside metabolism is regulated by various anti-metabolic drugs for the clinical treatment of PDAC. Despite various challenges, such as poor drug delivery efficiency and off-target side effects, metabolic modification and intervention are emerging as promising strategies for PDAC therapy, enabled by the rapid development of nanotechnology-based drug delivery strategies. In this review, we discuss the metabolic characteristics of PDAC and highlight how the development of nanomedicine has boosted the development of new therapeutics for PDAC by modulating critical targets in metabolic reprogramming.

Metabolic classifications of renal cell carcinoma reveal intrinsic connections with clinical and immune characteristics

BACKGROUND

Kidney cancer undergoes a dramatic metabolic shift and has demonstrated responsiveness to immunotherapeutic intervention. However, metabolic classification and the associations between metabolic alterations and immune infiltration in Renal cell carcinoma still remain elucidative.

METHODS

Unsupervised consensus clustering was conducted on the TCGA cohorts for metabolic classification. GESA, mRNAsi, prognosis, clinical features, mutation load, immune infiltration and differentially expressed gene differences among different clusters were compared. The prognosis model and nomograms were constructed based on metabolic gene signatures and verified using external ICGC datasets. Immunohistochemical results from Human Protein Atlas database and Tongji hospital were used to validate gene expression levels in normal tissues and tumor samples. CCK8, apoptosis analysis, qPCR, subcutaneously implanted murine models and flowcytometry analysis were applied to investigate the roles of ACAA2 in tumor progression and anti-tumor immunity.

RESULTS

Renal cell carcinoma was classified into 3 metabolic subclusters and the subcluster with low metabolic profiles displayed the poorest prognosis, highest invasiveness and AJCC grade, enhanced immune infiltration but suppressive immunophenotypes. ACAA2, ACAT1, ASRGL1, AKR1B10, ABCC2, ANGPTL4 were identified to construct the 6 gene-signature prognosis model and verified both internally and externally with ICGC cohorts. ACAA2 was demonstrated as a tumor suppressor and was associated with higher immune infiltration and elevated PD-1 expression of CD8⁺ T cells.

CONCLUSIONS

Our research proposed a new metabolic classification method for RCC and revealed intrinsic associations between metabolic phenotypes and immune profiles. The identified gene signatures might serve as key factors bridging tumor metabolism and tumor immunity and warrant further in-depth investigations.

Metabolic reprogramming of glutamine involved in tumorigenesis, multidrug resistance and tumor immunity

Glutamine, as the most abundant amino acid in the body, participates in the biological synthesis of nucleotides and other non-essential amino acids in the process of cell metabolism. Recent studies showed that glutamine metabolic reprogramming is an important signal during cancer development and progression. This metabolic signature in cancer cells can promote the development of cancer by activating multiple signaling pathways and oncogenes. It can also be involved in tumor immune regulation and promote the development of drug resistance to tumors. In this review, we mainly summarize the role of glutamine metabolic reprogramming in tumors, including the regulation of multiple signaling pathways. We further discussed the promising tumor treatment strategy by targeting glutamine metabolism alone or in combination with chemotherapeutics.

Harnessing bioactive nanomaterials in modulating tumor glycolysis-associated metabolism

Glycolytic reprogramming is emerging as a hallmark of various cancers and a promising therapeutic target. Nanotechnology is revolutionizing the anti-tumor therapeutic approaches associated with glycolysis. Finely controlled chemical composition and nanostructure provide nanomaterials unique advantages, enabling an excellent platform for integrated drug delivery, biochemical modulation and combination therapy. Recent studies have shown promising potential of nanotherapeutic strategies in modulating tumor glycolytic metabolism alone or in combination with other treatments such as chemotherapy, radiotherapy and immunotherapy. To foster more innovation in this cutting-edge and interdisciplinary field, this review summarizes recent understandings of the origin and development of tumor glycolysis, then provides the latest advances in how nanomaterials modulate tumor glycolysis-related metabolism. The interplay of nanochemistry, metabolism and immunity is highlighted. Ultimately, the challenges and opportunities are presented.

Isotope tracing reveals distinct substrate preference in murine melanoma subtypes with differing anti-tumor immunity

BACKGROUND

Research about tumor "metabolic flexibility"-the ability of cells to toggle between preferred nutrients depending on the metabolic context-has largely focused on obesity-associated cancers. However, increasing evidence for a key role for nutrient competition in the tumor microenvironment, as well as for substrate regulation of immune function, suggests that substrate metabolism deserves reconsideration in immunogenic tumors that are not strongly associated with obesity.

METHODS

We compare two murine models: immunologically cold YUMM1.7 and immunologically-hot YUMMER1.7. We utilize stable isotope and radioisotope tracer-based metabolic flux studies as well as gas and liquid chromatography-based metabolomics analyses to comprehensively probe substrate preference in YUMM1.7 and YUMMER1.7 cells, with a subset of studies on the impact of available metabolites across a panel of five additional melanoma cell lines. We analyze bulk RNA-seq data and identify increased expression of amino acid and glucose metabolism genes in YUMMER1.7. Finally, we analyze melanoma patient RNA-seq data to identify potential prognostic predictors rooted in metabolism.

RESULTS

We demonstrate using stable isotope tracer-based metabolic flux studies as well as gas and liquid chromatography-based metabolomics that immunologically-hot melanoma utilizes more glutamine than immunologically-cold melanoma in vivo and in vitro. Analyses of human melanoma RNA-seq data demonstrate that glutamine transporter and other anaplerotic gene expression positively correlates with lymphocyte infiltration and function.

CONCLUSIONS

Here, we highlight the importance of understanding metabolism in non-obesity-associated cancers, such as melanoma. This work advances the understanding of the correlation between metabolism and immunogenicity in the tumor microenvironment and provides evidence supporting metabolic gene expression as potential prognostic factors of melanoma progression and may inform investigations of adjunctive metabolic therapy in melanoma.

TRIAL REGISTRATION

Deidentified data from The Cancer Genome Atlas were analyzed.

Development and experimental verification of a prognosis model for cuproptosis-related subtypes in HCC

BACKGROUND

Cuproptosis is a recently discovered mechanism of programmed cell death caused by intracellular aggregation of mitochondrial lipoylated proteins and destabilization of iron-sulfur proteins triggered by copper. Hepatocellular carcinoma (HCC) is a common malignant tumor with a poor prognosis. We aimed to predict the survival of patients with HCC using the cuproptosis-related gene (CRG) expression.

METHODS

We analyzed the expression, methylation, and mutation status of CRGs in 538 HCC patients and correlated the date with clinical prognosis. HCC patients were divided into two clusters based on their CRG expression. The relationship between CRGs, risk genes, and the immune microenvironment was analyzed using the CIBERSORT algorithm and the single-cell data analysis method. A cuproptosis risk model was constructed according to the five risk genes using the LASSO COX method. To facilitate the clinical applicability of the proposed risk model, we constructed a nomogram and conducted an antineoplastic drug sensitivity analysis.

RESULTS

Our results suggest that the expression levels of CRGs in HCC are regulated by methylation. The prognoses were significantly different between the patients of the two clusters. The prognostic risk score positively correlated with memory T cell activation and negatively correlated with natural killer (NK) and regulatory T cell activation.

CONCLUSION

Our findings indicate the involvement of CRG regulation in HCC and provide new insights into prognosis assessment. Drug sensitivity analysis predicted drug candidates for the treatment of patients with different HCC subtypes.

Oncogenic functions of the FOXC2 transcription factor: a hallmarks of cancer perspective

Epigenetic regulation of gene expression is a fundamental determinant of molecular and cellular function, and epigenetic reprogramming in the context of cancer has emerged as one of the key enabling characteristics associated with acquisition of the core hallmarks of this disease. As such, there has been renewed interest in studying the role of transcription factors as epigenetic regulators of gene expression in cancer. In this review, we discuss the current state of knowledge surrounding the oncogenic functions of FOXC2, a transcription factor that frequently becomes dysregulated in a variety of cancer types. In addition to highlighting the clinical impact of aberrant FOXC2 activity in cancer, we discuss mechanisms by which this transcription factor becomes dysregulated in both tumor and tumor-associated cells, placing particular emphasis on the ways in which FOXC2 promotes key hallmarks of cancer progression. Finally, we bring attention to important issues related to the oncogenic dysregulation of FOXC2 that must be addressed going forward in order to improve our understanding of FOXC2-mediated cancer progression and to guide prognostic and therapeutic applications of this knowledge in clinical settings.

Methionine deprivation inhibits glioma growth through downregulation of CTSL

The metabolism of tumor cells is characterized by the regulation of demand, nutrient supply and metabolic enzymes, which are different in cancer tissues from those in corresponding healthy tissues. There is growing evidence that dietary composition influences biological processes that contribute to tumor incidence and progression as much as genetic status. One possibility for specific dietary interventions in cancer patients is to limit methionine intake. The role of methionine metabolism in tumors suggests that interference with the methionine metabolism network by either drug or environmental effects may show substantial therapeutic effects, but the molecular mechanism is not completely clear. In this study, methionine deprivation was found to downregulate cathepsin L (CTSL) and induce proliferation inhibition in glioma cells. We also demonstrated that CTSL is a tumor-related gene, and promotes the proliferation and invasion of glioma. Our results showed that the treatment of methionine metabolism and CTSL related genes in glioma cells may be a novel strategy for glioma therapy in the future.

Metabolic modulation of immune checkpoints and novel therapeutic strategies in cancer

Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) or programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1)-based immune checkpoint inhibitors (ICIs) have led to significant improvements in the overall survival of patients with certain cancers and are expected to benefit patients by achieving complete, long-lasting remissions and cure. However, some patients who receive ICIs either fail treatment or eventually develop immunotherapy resistance. The existence of such patients necessitates a deeper understanding of cancer progression, specifically nutrient regulation in the tumor microenvironment (TME), which includes both metabolic cross-talk between metabolites and tumor cells, and intracellular metabolism in immune and cancer cells. Here we review the features and behaviors of the TME and discuss the recently identified major immune checkpoints. We comprehensively and systematically summarize the metabolic modulation of tumor immunity and immune checkpoints in the TME, including glycolysis, amino acid metabolism, lipid metabolism, and other metabolic pathways, and further discuss the potential metabolism-based therapeutic strategies tested in preclinical and clinical settings. These findings will help to determine the existence of a link or crosstalk between tumor metabolism and immunotherapy, which will provide an important insight into cancer treatment and cancer research.

Cardio-Onco-Metabolism - Metabolic vulnerabilities in cancer and the heart

Cancer and cardiovascular diseases (CVDs) are the leading cause of death worldwide. Metabolic remodeling is a hallmark of both cancer and the failing heart. Tumors reprogram metabolism to optimize nutrient utilization and meet increased demands for energy provision, biosynthetic pathways, and proliferation. Shared risk factors for cancer and CVDs suggest intersecting mechanisms for disease pathogenesis and progression. In this review, we aim to highlight the role of metabolic remodeling in cancer and its potential to impair cardiac function. Understanding these mechanisms will help us develop biomarkers, better therapies, and identify patients at risk of developing heart disease after surviving cancer.

Comparative profiling of single-cell transcriptome reveals heterogeneity of tumor microenvironment between solid and acinar lung adenocarcinoma

BACKGROUND

The diversity of histologic composition reflects the inter- and intra-tumor heterogeneity of lung adenocarcinomas (LUADs) macroscopically. Insights into the oncological characteristics and tumor microenvironment (TME) of different histologic subtypes of LUAD at the single-cell level can help identify potential therapeutic vulnerabilities and combinational approaches to improve the survival of LUAD patients.

METHODS

Through comparative profiling of cell communities defined by scRNA-seq data, we characterized the TME of LUAD samples of distinct histologic subtypes, with relevant results further confirmed in multiple bulk transcriptomic, proteomic datasets and an independent immunohistochemical validation cohort.

RESULTS

We find that the hypoxic and acidic situation is the worst in the TME of solid LUADs compared to other histologic subtypes. Besides, the tumor metabolic preferences vary across histologic subtypes and may correspondingly impinge on the metabolism and function of immune cells. Remarkably, tumor cells from solid LUADs upregulate energy and substance metabolic activities, particularly the folate-mediated one-carbon metabolism and the key gene MTHFD2, which could serve as a potential therapeutic target. Additionally, ubiquitination modifications may also be involved in the progression of histologic patterns. Immunologically, solid LUADs are characterized by a predominance of exhausted T cells and immunosuppressive myeloid cells, where the hypoxic, acidified and nutrient-deprived TME has a non-negligible impact. Discrepancies in stromal cell function, evidenced by varying degrees of stromal remodeling and fibrosis, may also contribute to the specific immune phenotype of solid LUADs.

CONCLUSIONS

Overall, our research proposes several potential entry points to improve the immunosuppressive TME of solid LUADs, thereby synergistically potentiating their immunotherapeutic efficacy, and may provide precise therapeutic strategies for LUAD patients of distinct histologic subtype constitution.

Lactate Dehydrogenase and its clinical significance in pancreatic and thoracic cancers

The energy metabolism of tumor cells is considered one of the hallmarks of cancer because it is different from normal cells and mainly consists of aerobic glycolysis, fatty acid oxidation, and glutaminolysis. It is about one hundred years ago since Warburg observed that cancer cells prefer aerobic glycolysis even in normoxic conditions, favoring their high proliferation rate. A pivotal enzyme driving this phenomenon is lactate dehydrogenase (LDH), and this review describes prognostic and therapeutic opportunities associated with this enzyme, focussing on tumors with limited therapeutic strategies and life expectancy (i.e., pancreatic and thoracic cancers). Expression levels of LDH-A in pancreatic cancer tissues correlate with clinicopathological features: LDH-A is overexpressed during pancreatic carcinogenesis and showed significantly higher expression in more aggressive tumors. Similarly, LDH levels are a marker of negative prognosis in patients with both adenocarcinoma or squamous cell lung carcinoma, as well as in malignant pleural mesothelioma. Additionally, serum LDH levels may play a key role in the clinical management of these diseases because they are associated with tissue damage induced by tumor burden. Lastly, we discuss the promising results of strategies targeting LDH as a treatment strategy, reporting recent preclinical and translational studies supporting the use of LDH-inhibitors in combinations with current/novel chemotherapeutics that can synergistically target the oxygenated cells present in the tumor.

[The tumor microenvironment-relay station for prognosis and therapy response]

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide with a dismal prognosis. Besides tobacco and alcohol abuse, human papilloma virus (HPV) infection is an independent risk factor, particularly in oropharyngeal squamous cell carcinomas (OPSCC). One key determinant of therapy response and prognosis is the tumor immune microenvironment (TIME). A strong anti-tumor immune response represents an important mechanism of tumor cell killing. Another major determinant is the tumor metabolism. One feature of tumor cells is their reliance on glycolysis instead of oxidative phosphorylation (OXPHOS) for energy production despite sufficient oxygen supply.The presented studies were based on several different clinically and pathologically well annotated HNSCC cohorts. Immunohistochemical stainings were performed on tissue microarrays and whole slides against p16, different immune cell markers, and metabolic markers. DNA and mRNA were extracted to detect HPV and assess immune-related and metabolic genes via RT-PCR and Nanostring.An initial assessment of HPV infection frequencies in different HNSCC cohorts showed that socioeconomic and regional factors strongly influence HPV prevalence. An analysis of the immunological and metabolic differences of HPV-positive and HPV-negative OPSCC demonstrated an enhanced anti-tumor immune response together with increased levels of OXPHOS metabolism in HPV-positive OPSCC. In a subsequent study, a strong anti-tumor immune response together with an OXPHOS metabolism was associated with improved short-term survival in HNSCC. Finally, TIME differences of HNSCC primary tumors and recurrent tumors were analyzed to understand the poor therapeutic response of recurrences and discovered an overall decrease of tumor infiltrating lymphocytes with significant loss of CD8-positive T cells and B lymphocytes as well as a significant decrease of tertiary lymphoid structures in recurrences after chemoradiation.These results demonstrate the clinical and molecular differences of HPV-positive and HPV-negative HNSCC with a focus on OPSCC. Furthermore, they delineate the interdependencies of TIME and tumor metabolism in HNSCC in general and stress their impact on therapy response. Additionally, they show an impairment of anti-tumor immune response in recurrences after chemoradiation, which indicates immune evasion as one recurrence driver.

Emerging roles of fatty acid metabolism in cancer and their targeted drug development

Metabolic reprogramming is now considered as one of hallmark of tumor cells and provides them with a selective survival/growth advantage to resist harsh micro-environmental stress. Fatty acid (FA) metabolism of tumor cells supports the biosynthetic needs and provides fuel sources for energy supply. Since FA metabolic reprogramming is a critical link in tumor metabolism, its various roles in tumors have attracted increasing interest. Herein, we review the mechanisms through which cancer cells rewire their FA metabolism with a focus on the pathway of FA metabolism and its targeting drug development. The failure and successful cases of targeting tumor FA metabolism are expected to bypass the metabolic vulnerability and improve the efficacy of targeted therapy.

Historical perspective of tumor glycolysis: A century with Otto Warburg

Tumors have long been known to rewire their metabolism to endorse their proliferation, growth, survival, and invasiveness. One of the common characteristics of these alterations is the enhanced glucose uptake and its subsequent transformation into lactic acid by means of glycolysis, regardless the availability of oxygen or the mitochondria effectiveness. This phenomenon is called the "Warburg effect", which has turned into a century of age now, since its first disclosure by German physiologist Otto Heinrich Warburg. Since then, this peculiar metabolic switch in tumors has been addressed by extensive studies covering several areas of research. In this historical perspective, we aim at illustrating the evolution of these studies over time and their implication in various fields of science.

Impact of tumor microenvironment on adoptive T cell transfer activity

Recent advances in immunotherapy have revolutionized the treatment of cancer. The use of adoptive cell therapies (ACT) such as those based on tumor infiltrating lymphocytes (TILs) or genetically modified cells (transgenic TCR lymphocytes or CAR-T cells), has shown impressive results in the treatment of several types of cancers. However, cancer cells can exploit mechanisms to escape from immunosurveillance resulting in many patients not responding to these therapies or respond only transiently. The failure of immunotherapy to achieve long-term tumor control is multifactorial. On the one hand, only a limited percentage of the transferred lymphocytes is capable of circulating through the bloodstream, interacting and crossing the tumor endothelium to infiltrate the tumor. Metabolic competition, excessive glucose consumption, the high level of lactic acid secretion and the extracellular pH acidification, the shortage of essential amino acids, the hypoxic conditions or the accumulation of fatty acids in the tumor microenvironment (TME), greatly hinder the anti-tumor activity of the immune cells in ACT therapy strategies. Therefore, there is a new trend in immunotherapy research that seeks to unravel the fundamental biology that underpins the response to therapy and identifies new approaches to better amplify the efficacy of immunotherapies. In this review we address important aspects that may significantly affect the efficacy of ACT, indicating also the therapeutic alternatives that are currently being implemented to overcome these drawbacks.

Tumor metabolism destruction via metformin-based glycolysis inhibition and glucose oxidase-mediated glucose deprivation for enhanced cancer therapy

Cancer cells rely on glycolysis to support a high proliferation rate. Metformin (Met) is a promising drug for tumor treatment that targets hexokinase 2 (HK2) to block the glycolytic process, thereby further disrupting the metabolism of cancer cells. Herein, an intelligent nanomedicine based on glucose deprivation and glycolysis inhibition is creatively constructed for enhanced cancer synergistic treatment. In brief, Met and glucose oxidase (GOx) was encapsulated into histidine/zeolitic imidazolate framework-8 (His/ZIF-8), which was followed by coating with Arg-Gly-Asp (RGD) peptides to obtain the desired nanomedicine (Met/GOx@His/ZIF-8∼RGD). This smart nanomedicine presents the controllable Met and GOx release behavior in an acidic responsive manner. The liberated Met blocks the glycolysis process via suppressing the activity of HK2 and impairing ATP production, which activates the AMP-activated protein kinase (AMPK) pathway and p53 pathway and damages the Warburg effect, eventually leading to cells apoptosis. And the GOx boosts the glucose shortage for starvation therapy by depleting accumulated glucose. According to in vitro and in vivo assays, the combination of glycolysis inhibition and starvation therapy demonstrates efficient cancer cells growth suppression and superior antitumor properties compared to the Met based or GOx-mediated monotherapy. This work provides an advanced therapeutic strategy via disrupting cellular metabolism against cancer. STATEMENT OF SIGNIFICANCE: The obtained nanomedicine (Met/GOx@His/ZIF-8∼RGD) presents the controllable Met and glucose oxidase (GOx) release behavior in an acidic responsive manner. The liberated Met blocks the glycolysis process via suppressing the activity of HK2 and impairing ATP production, which activates the AMP-activated protein kinase (AMPK) pathway and p53 pathway and damages the Warburg effect, eventually leading to cells apoptosis. And the GOx boosts the glucose shortage for starvation therapy by depleting accumulated glucose. The combination of glycolysis inhibition and starvation therapy demonstrate the efficient suppression of cancer cells growth and the superior antitumor properties when compared to the Met based or GOx-mediated monotherapy.

Ferroptosis in hematological malignancies and its potential network with abnormal tumor metabolism

Ferroptosis, a new type of regulated cell death, displays characteristics that transparently differ from apoptosis, autophagy and necroptosis. There is growing appreciation that targeting ferroptosis is potentially a novel strategy in anti-tumor therapy, especially for invasive malignancies demonstrating resistance to chemotherapy. Almost all types of cancer cells depend on abnormal metabolic activities to participate in vicious progression, giving the possibility to interfere with underlying metabolic preferences and compromise malignant cells by inducing ferroptosis. In this perspective, we give an overview of potential interactions between ferroptosis and abnormal tumor metabolism, with special focus on systematic researches in hematological malignancies.

Circ_0001093 promotes glutamine metabolism and cancer progression of esophageal squamous cell carcinoma by targeting miR-579-3p/glutaminase axis

Increasing studies indicate that circular RNAs (circRNAs) play critical roles in tumor metabolism of multiple cancers. However, the contribution of circRNAs in glutamine metabolism of esophageal squamous cell carcinoma (ESCC) remains elusive. The objective of this research was to investigate the role and mechanism of circRNA hsa_circ_0001093 (circ_0001093) in the glutamine metabolism and tumorigenesis of ESCC. Circ_0001093, microRNA-579-3p (miR-579-3p) and glutaminase (GLS) expressions in ESCC tissues and cell lines were measured by qRT-PCR, tissue array or Western blot. Cell proliferation, invasion and migration were assessed by CCK-8 or transwell assays. Glutamine consumption, glutamate and ATP production were detected by indicated assay kits. The relationships between circ_0001093 and miR-579-3p or GLS mRNA were investigated by bioinformatics analysis, RNA pull-down, luciferase reporter and RNA immunoprecipitation (RIP) assays. Here, we found that circ_0001093 expression was up-regulated in ESCC tissues and cell lines. Increased circ_0001093 expression predicted an unfavourable prognosis, and was associated with the lymph node metastasis, TNM staging and tumor size in ESCC tissues. Circ_0001093 knockdown suppressed cell proliferation, invasion, migration and glutamine metabolism of ESCC cells, while circ_0001093 over-expression showed the opposite effects. Mechanistically, circ_0001093 acted as a competing endogenous RNA (ceRNA) by sponging miR-579-3p, thereby increasing GLS expression. Furthermore, the inhibitory effects of circ_0001093 knockdown on the invasion, migration and glutamine metabolism were partly rescued by miR-579-3p inhibition or GLS over-expression in ESCC cells. Additionally, miR-579-3p expression was down-regulated in ESCC tissues, while GLS expression was up-regulated. In conclusion, this study first provides evidence that the circ_0001093/miR-579-3p/GLS regulatory network can affect glutamine metabolism and malignant phenotype of ESCC, which can further impact ESCC progression.

YAP1 activation and Hippo pathway signaling in the pathogenesis and treatment of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA), the second most common primary liver cancer, is a highly lethal epithelial cell malignancy exhibiting features of cholangiocyte differentiation. iCCAs can potentially develop from multiple cell types of origin within liver, including immature or mature cholangiocytes, hepatic stem cells/progenitor cells, and from transdifferentiation of hepatocytes. Understanding the molecular mechanisms and genetic drivers that diversely drive specific cell lineage pathways leading to iCCA has important biological and clinical implications. In this context, activation of the YAP1-TEAD dependent transcription, driven by Hippo-dependent or -independent diverse mechanisms that lead to the stabilization of YAP1 is crucially important to biliary fate commitment in hepatobiliary cancer. In preclinical models, YAP1 activation in hepatocytes or cholangiocytes is sufficient to drive their malignant transformation into iCCA. Moreover, nuclear YAP1/TAZ is highly prevalent in human iCCA irrespective of the varied etiology, and significantly correlates with poor prognosis in iCCA patients. Based on the ubiquitous expression and diverse physiologic roles for YAP1/TAZ in the liver, recent studies have further revealed distinct functions of active YAP1/TAZ in regulating tumor metabolism, as well as the tumor immune microenvironment. In the current review, we discuss our current understanding of the various roles of the Hippo-YAP1 signaling in iCCA pathogenesis, with a specific focus on the roles played by the Hippo-YAP1 pathway in modulating biliary commitment and oncogenicity, iCCA metabolism, and immune microenvironment. We also discuss the therapeutic potential of targeting the YAP1/TAZ-TEAD transcriptional machinery in iCCA, its current limitations, and what future studies are needed to facilitate clinical translation.

A metabolic acidity-activatable calcium phosphate probe with fluorescence signal amplification capabilities for non-invasive imaging of tumor malignancy

Dysregulated energy metabolism has recently been recognized as an emerging hallmark of cancer. Tumor cells, which are characterized by abnormal glycolysis, exhibit a lower extracellular pH (6.5-7.0) than normal tissues (7.2-7.4), providing a promising target for tumor-specific imaging and therapy. However, most pH-sensitive materials are unable to distinguish such a subtle pH difference owing to their wide and continuous pH-responsive range. In this study, we developed an efficient strategy for the fabrication of a tumor metabolic acidity-activatable calcium phosphate (CaP) fluorescent probe (termed MACaP9). Unlike traditional CaP-based biomedical nanomaterials, which only work within more acidic organelles, such as endosomes and lysosomes (pH 4.0-6.0), MACaP9 could not only specifically respond to the tumor extra-cellular pH but also rapidly convert pH variations into a distinct fluorescence signal to visually distinguish tumor from normal tissues. The superior sensitivity and specificity of MACaP9 enabled high-contrast visualization of a broad range of tumors, as well as small tumor lesions.

Modulation of DNA/RNA Methylation Signaling Mediating Metabolic Homeostasis in Cancer

Nucleic acid methylation is a fundamental epigenetic mechanism that impinges upon several cellular attributes, including metabolism and energy production. The dysregulation of deoxyribonucleic acid (DNA)/ribonucleic acid (RNA) methylation can lead to metabolic rewiring in the cell, which in turn facilitates tumor development. Here, we review the current knowledge on the interplay between DNA/RNA methylation and metabolic programs in cancer cells. We also discuss the mechanistic role of these pathways in tumor development and progression.

Multi-omics analysis defines 5-fluorouracil drug resistance in 3D HeLa carcinoma cell model

Cervical cancer is a serious health problem in women around the globe. However, the use of clinical drug is seriously dampened by the development of drug resistance. Efficient in vitro tumor model is essential to improve the efficiency of drug screening and the accuracy of clinical application. Multicellular tumor spheroids (MTSs) can in a way recapitulates tumor traits in vivo, thereby representing a powerful transitional model between 2D monolayer culture and xenograft. In this study, based on the liquid overlay method, a protocol for rapid generation of the MTSs with uniform size and high reproducibility in a high-throughput manner was established. As expected, the cytotoxicity results showed that there was enhanced 5-fluorouracil (5-FU) resistance of HeLa carcinoma cells in 3D MTSs than 2D monolayer culture with a resistance index of 5.72. In order to obtain a holistic view of the molecular mechanisms that drive 5-FU resistance in 3D HeLa carcinoma cells, a multi-omics study was applied to discover hidden biological regularities. It was observed that in the 3D MTSs mitochondrial function-related proteins and the metabolites of the tricarboxylic acid cycle (TCA cycle) were significantly decreased, and the cellular metabolism was shifted towards glycolysis. The differences in the protein synthesis, processing, and transportation between 2D monolayer cultures and 3D MTSs were significant, mainly in the heat shock protein family, with the up-regulation of protein folding function in endoplasmic reticulum (ER), which promoted the maintenance of ER homeostasis in the 3D MTSs. In addition, at the transcript and protein level, the expression of extracellular matrix (ECM) proteins (e.g., laminin and collagen) were up-regulated in the 3D MTSs, which enhanced the physical barrier of drug penetration. Summarizing, this study formulates a rapid, scalable and reproducible in vitro model of 3D MTS for drug screening purposes, and the findings establish a critical role of glycolytic metabolism, ER hemostasis and ECM proteins expression profiling in tumor chemoresistance of HeLa carcinoma cells towards 5-FU.

Avenues of research in dietary interventions to target tumor metabolism in osteosarcoma

Osteosarcoma (OS) is the most frequent primary bone cancer, affecting mostly children and adolescents. Although much progress has been made throughout the years towards treating primary OS, the 5-year survival rate for metastatic OS has remained at only 20% for the last 30 years. Therefore, more efficient treatments are needed. Recent studies have shown that tumor metabolism displays a unique behavior, and plays important roles in tumor growth and metastasis, making it an attractive potential target for novel therapies. While normal cells typically fuel the oxidative phosphorylation (OXPHOS) pathway with the products of glycolysis, cancer cells acquire a plastic metabolism, uncoupling these two pathways. This allows them to obtain building blocks for proliferation from glycolytic intermediates and ATP from OXPHOS. One way to target the metabolism of cancer cells is through dietary interventions. However, while some diets have shown anticancer effects against certain tumor types in preclinical studies, as of yet none have been tested to treat OS. Here we review the features of tumor metabolism, in general and about OS, and propose avenues of research in dietary intervention, discussing strategies that could potentially be effective to target OS metabolism.

Noncoding RNAs link metabolic reprogramming to immune microenvironment in cancers

Altered metabolic patterns in tumor cells not only meet their own growth requirements but also shape an immunosuppressive microenvironment through multiple mechanisms. Noncoding RNAs constitute approximately 60% of the transcriptional output of human cells and have been shown to regulate numerous cellular processes under developmental and pathological conditions. Given their extensive action mechanisms based on motif recognition patterns, noncoding RNAs may serve as hinges bridging metabolic activity and immune responses. Indeed, recent studies have shown that microRNAs, long noncoding RNAs and circRNAs are widely involved in tumor metabolic rewiring, immune cell infiltration and function. Hence, we summarized existing knowledge of the role of noncoding RNAs in the remodeling of tumor metabolism and the immune microenvironment, and notably, we established the TIMELnc manual, which is a free and public manual for researchers to identify pivotal lncRNAs that are simultaneously correlated with tumor metabolism and immune cell infiltration based on a bioinformatic approach.

Breast cancer growth and proliferation is suppressed by the mitochondrial targeted furazano[3,4-b]pyrazine BAM15

BACKGROUND

Enhanced metabolic plasticity and diversification of energy production is a hallmark of highly proliferative breast cancers. This contributes to poor pharmacotherapy efficacy, recurrence, and metastases. We have previously identified a mitochondrial-targeted furazano[3,4-b]pyrazine named BAM15 that selectively reduces bioenergetic coupling efficiency and is orally available. Here, we evaluated the antineoplastic properties of uncoupling oxidative phosphorylation from ATP production in breast cancer using BAM15.

METHODS

The anticancer effects of BAM15 were evaluated in human triple-negative MDA-MB-231 and murine luminal B, ERα-negative EO771 cells as well as in an orthotopic allograft model of highly proliferative mammary cancer in mice fed a standard or high fat diet (HFD). Untargeted transcriptomic profiling of MDA-MB-231 cells was conducted after 16-h exposure to BAM15. Additionally, oxidative phosphorylation and electron transfer capacity was determined in permeabilized cells and excised tumor homogenates after treatment with BAM15.

RESULTS

BAM15 increased proton leak and over time, diminished cell proliferation, migration, and ATP production in both MDA-MB-231 and EO771 cells. Additionally, BAM15 decreased mitochondrial membrane potential, while inducing apoptosis and reactive oxygen species accumulation in MDA-MB-231 and EO771 cells. Untargeted transcriptomic profiling of MDA-MB-231 cells further revealed inhibition of signatures associated with cell survival and energy production by BAM15. In lean mice, BAM15 lowered body weight independent of food intake and slowed tumor progression compared to vehicle-treated controls. In HFD mice, BAM15 reduced tumor growth relative to vehicle and calorie-restricted weight-matched controls mediated in part by impaired cell proliferation, mitochondrial respiratory function, and ATP production. LC-MS/MS profiling of plasma and tissues from BAM15-treated animals revealed distribution of BAM15 in adipose, liver, and tumor tissue with low abundance in skeletal muscle.

CONCLUSIONS

Collectively, these data indicate that mitochondrial uncoupling may be an effective strategy to limit proliferation of aggressive forms of breast cancer. More broadly, these findings highlight the metabolic vulnerabilities of highly proliferative breast cancers which may be leveraged in overcoming poor responsiveness to existing therapies.

The MEMIC: An ex vivo system to model the complexity of the tumor microenvironment

There is an urgent need for accurate, scalable and cost-efficient models of the tumor microenvironment. Here, we detail how to fabricate and use the metabolic microenvironment chamber (MEMIC) – a 3D-printed ex vivo model of intratumoral heterogeneity. A major driver of the cellular and molecular diversity in tumors is accessibility to the blood stream. Whereas perivascular tumor cells have direct access to oxygen and nutrients, cells further from the vasculature must survive under progressively more ischemic environments. The MEMIC simulates this differential access to nutrients, allow co-culturing any number of cell types, and it is optimized for live imaging and other microscopy-based analyses. Owing to a modular design and full experimental control, the MEMIC provides insights into the tumor microenvironment that would be difficult to obtain via other methods. As proof of principle, we show that cells sense gradual changes in metabolite concentration leading to predictable molecular and cellular spatial patterns. We propose the MEMIC as a complement to standard in vitro and in vivo experiments, diversifying the tools available to accurately model, perturb and monitor the tumor microenvironment.

Editor's choice: We present how to fabricate the MEMIC, an experimental model of the tumor microenvironment, describing proof-of-principle experiments and providing image analysis tools that are helpful when using this system.

Physiological impact of in vivo stable isotope tracing on cancer metabolism

Background

There is growing interest in the analysis of tumor metabolism to identify cancer-specific metabolic vulnerabilities and therapeutic targets. Finding of such candidate metabolic pathways mainly relies on the highly sensitive identification and quantitation of numerous metabolites and metabolic fluxes using metabolomics and isotope tracing analyses. However, nutritional requirements and metabolic routes used by cancer cells cultivated in vitro do not always reflect the metabolic demands of malignant cells within the tumor milieu. Therefore, to understand how the metabolism of tumor cells in its physiological environment differs from that of normal cells, these analyses must be performed in vivo.

Scope of Review

This review covers the physiological impact of the exogenous administration of a stable isotope tracer into cancer animal models. We discuss specific aspects of in vivo isotope tracing protocols based on discrete bolus injections of a labeled metabolite: the tracer administration per se and the fasting period prior to it. In addition, we illustrate the complex physiological scenarios that arise when studying tumor metabolism – by isotopic labeling in animal models fed with a specific amino acid restricted diet. Finally, we provide strategies to minimize these limitations.

Major Conclusions

There is growing evidence that metabolic dependencies in cancers are influenced by tissue environment, cancer lineage, and genetic events. An increasing number of studies describe discrepancies in tumor metabolic dependencies when studied in in vitro settings or in vivo models, including cancer patients. Therefore, in-depth in vivo profiling of tumor metabolic routes within the appropriate pathophysiological environment will be key to identify relevant alterations that contribute to cancer onset and progression.

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In vivo isotope tracing is the state-of-the-art approach to study tumor metabolism.

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In vivo tracer administration challenges the physiological metabolism of mice.

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Interorgan conversion of the tracer might confound tumor labeling patterns.

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Mouse fasting before in vivo tracing impacts on systemic and tumor metabolism.

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Optimization is key to minimize physiological alterations linked to in vivo tracing.

The molecular chaperone TRAP1 in cancer: From the basics of biology to pharmacological targeting

TRAP1, the mitochondrial component of the Hsp90 family of molecular chaperones, displays important bioenergetic and proteostatic functions. In tumor cells, TRAP1 contributes to shape metabolism, dynamically tuning it with the changing environmental conditions, and to shield from noxious insults. Hence, TRAP1 activity has profound effects on the capability of neoplastic cells to evolve towards more malignant phenotypes. Here, we discuss our knowledge on the biochemical functions of TRAP1 in the context of a growing tumor mass, and we analyze the possibility of targeting its chaperone functions for developing novel anti-neoplastic approaches.

Targeting immunometabolism of neoplasms by interleukins: A promising immunotherapeutic strategy for cancer treatment

In recent years, tumor metabolism has become a prevalent research topic for scientists and pharmaceutical companies. As research in the field has progressed, the metabolism-based therapy of tumors has ushered in new opportunities. Most tumors emerge and evolve under selective pressure from their microenvironment, which promotes the diversification of both neoplastic and non-neoplastic compartments of the tumor microenvironment (TME), and finally reaches a certain degree of intratumoral heterogeneity. As a result of the tumor intratumoral heterogeneity, tumor cells often possess a complex energy metabolism phenotype. During tumor progression, the metabolism for both tumor parenchyma and stroma is reprogrammed. The tumor stroma mainly consists of the extracellular matrix, fibroblasts, and immune cells. Interestingly, tumor-infiltrating immune cells utilize different metabolites based on their subtype and function, and these immunometabolic pathways can be modified in the TME. In particular, interleukins play a vital role in the activation and differentiation of immune cells and have exhibited multiple effects on tumor cell neoplasia, invasion, and metastasis. In this review, we summarize the common mechanisms of interleukins affecting the tumor and tumor-infiltrating immune cells metabolically and discuss how these mechanisms may lead to novel therapeutic opportunities. This review might contribute to the novel development of cancer immunotherapy.

Preclinical efficacy against acute myeloid leukaemia of SH1573, a novel mutant IDH2 inhibitor approved for clinical trials in China

Acute myeloid leukaemia (AML) is the most common form of acute leukaemia in adults, with increasing incidence with age and a generally poor prognosis. Almost 20% of AML patients express mutant isocitrate dehydrogenase 2 (mIDH2), which leads to the accumulation of the carcinogenic metabolite 2-hydroxyglutarate (2-HG), resulting in poor prognosis. Thus, global institutions have been working to develop mIDH2 inhibitors. SH1573 is a novel mIDH2 inhibitor that we independently designed and synthesised. We have conducted a comprehensive study on its pharmacodynamics, pharmacokinetics and safety. First, SH1573 exhibited a strong selective inhibition of mIDH2 R140Q protein, which could effectively reduce the production of 2-HG in cell lines, serum and tumors of an animal model. It could also promote the differentiation of mutant AML cell lines and granulocytes in PDX models. Then, it was confirmed that SH1573 possessed characteristics of high bioavailability, good metabolic stability and wide tissue distribution. Finally, toxicological data showed that SH1573 had no effects on the respiratory system, cardiovascular system and nervous system, and was genetically safe. This research successfully promoted the approval of SH1573 for clinical trials (CTR20200247). All experiments demonstrated that, as a potential drug against mIDH2 R140Q acute myeloid leukaemia, SH1573 was effective and safe.

In vivo detection of distal tumor glycolytic flux stimulated by hepatic ablation in a breast cancer model using hyperpolarized 13C MRI

PURPOSE

Hepatic thermal ablation therapy can result in c-Met-mediated off-target stimulation of distal tumor growth. The purpose of this study was to determine if a similar effect on tumor metabolism could be detected in vivo with hyperpolarized ¹³C MRI.

MATERIALS AND METHODS

In this prospective study, female Fisher rats (n = 28, 120-150 g) were implanted with R3230 rat breast adenocarcinoma cells and assigned to either: sham surgery, hepatic radiofrequency ablation (RFA), or hepatic RFA + adjuvant c-Met inhibition with PHA-665752 (RFA + PHA). PHA-665752 was administered at 0.83 mg/kg at 24 h post-RFA. Tumor growth was measured daily. MRI was performed 24 h before and 72 h after treatment on 14 rats, and the conversion of ¹³C-pyruvate into ¹³C-lactate within each tumor was quantified as lactate:pyruvate ratio (LPR). Comparisons of tumor growth and LPR were performed using paired and unpaired t-tests.

RESULTS

Hepatic RFA alone resulted in increased growth of the distant tumor compared to sham treatment (0.50 ± 0.13 mm/day versus 0.11 ± 0.07 mm/day; p < 0.001), whereas RFA + PHA (0.06 ± 0.13 mm/day) resulted in no significant change from sham treatment (p = 0.28). A significant increase in LPR was seen following hepatic RFA (+0.016 ± 0.010, p = 0.02), while LPR was unchanged for sham treatment (-0.048 ± 0.051, p = 0.10) or RFA + PHA (0.003 ± 0.041, p = 0.90).

CONCLUSION

In vivo hyperpolarized ¹³C MRI can detect hepatic RFA-induced increase in lactate flux within a distant R3230 tumor, which correlates with increased tumor growth. Adjuvant inhibition of c-Met suppresses these off-target effects, supporting a role for the HGF/c-Met signaling axis in these tumorigenic responses.

Perturbations of cancer cell metabolism by the antidiabetic drug canagliflozin

Notwithstanding that high rates of glucose uptake and glycolysis are common in neoplasia, pharmacological efforts to inhibit glucose utilization for cancer treatment have not been successful. Recent evidence suggests that in addition to classical glucose transporters, sodium-glucose transporters (SGLTs) are expressed by cancers. We therefore investigated the possibility that SGLT inhibitors, which are used in treatment of type 2 diabetes, may exert antineoplastic activity by limiting glucose uptake. We show that the SGLT2 inhibitor canagliflozin inhibits proliferation of breast cancer cells. Surprisingly, the antiproliferative effects of canagliflozin are not affected by glucose availability nor by the level of expression of SGLT2. Canagliflozin reduces oxygen consumption and glutamine metabolism through the citric acid cycle. The antiproliferative effects of canagliflozin are linked to inhibition of glutamine metabolism that fuels respiration, which represents a previously unanticipated mechanism of its potential antineoplastic action.