Energy Metabolism Of Tumor Cells Research Articles

Characterization of the dehydrogenase-reductase DHRS2 and its involvement in histone deacetylase inhibition in urological malignancies.

Being implicated during tumor migration, invasion, clonogenicity, and proliferation, the nicotinamide adenine dinucleotide (NAD)/-phosphate (NADP)-dependent dehydrogenase/reductase member 2 (DHRS2) has been considered to be induced upon inhibition of histone deacetylases (HDACi). In this study, we evaluated the current knowledge on the underlying mechanisms of the (epi)genetic regulation of DHRS2, as well as its function during tumor progression. DHRS2 expression was evaluated on mRNA- and protein-level upon treatment with HDACi by means of qRT-PCR and western blot analyses, respectively. Re-analysis of RNA-sequencing data gained insight into expression of specific DHRS2 isoforms, while re-analysis of ATAC-sequencing data shed light on the chromatin accessibility at the DHRS2 locus. Further examination of the energy and lipid metabolism of HDACi-treated urologic tumor cells was performed using liquid chromatography-mass spectrometry. Enhanced DHRS2 expression levels upon HDACi treatment were directly linked to an enhanced chromatin accessibility at the DHRS2 locus. Particularly the DHRS2 ENST00000250383.11 protein-coding isoform was increased upon HDACi treatment. Application of the HDACi quisinostat only mildly influenced the energy metabolism of urologic tumor cells, though, the analysis of the lipid metabolism showed diminished sphingosine levels, as well as decreased S1P levels. Also the ratios of S1P/sphingosine and S1P/ceramides were reduced in all four quisinostat-treated urologic tumor cells. With the emphasis on urologic malignancies (testicular germ cell tumors, urothelial, prostate, and renal cell carcinoma), this study concluded that elevated DHRS2 levels are indicative of a successful HDACi treatment and, thereby offering a novel putative predictive biomarker.

Interference with mitochondrial metabolism could serve as a potential therapeutic strategy for advanced prostate cancer.

Metabolic reprogramming has been defined as a hallmark of malignancies. Prior studies have focused on the single nucleotide polymorphism (SNP) of POLG2 gene, which is reportedly responsible for encoding mitochondrial DNA genes and is implicated in the material and energy metabolism of tumor cells, whereas its function in prostate cancer has been elusive. Gene expression profile matrix and clinical information were downloaded from TCGA (The Cancer Genome Atlas) data portal, and GSE3325 and GSE8511 were retrieved from GEO (Gene Expression Omnibus) database. We conducted analysis of the relative expression of POLG2, clinical characterization, survival analysis, GO / KEGG and GSEA (Gene Set Enrichment Analysis) enrichment analysis in R and employed STRING portal to acquaint ourselves with the protein-protein interaction (PPI). IHC (Immunohistochemical) profiles of POLG2 protein between normal and cancerous tissues were consulted via HPA (Human protein atlas) database and the immunohistochemical POLG2 were verified between para-cancerous and cancerous tissues in tissue array. At the cellular level, Mitochondrial dysfunction assay, DNA synthesis test, wound healing assay, and invasion assay were implemented to further validate the phenotype of POLG2 knockdown in PCa cell lines. RT-qPCR and western blotting were routinely adopted to verify variations of molecular expression within epithelial mesenchymal transition (EMT). Results showed that POLG2 was over-expressed in most cancer types, and the over-expression of POLG2 was correlated with PCa progression and suggested poor OS (Overall Survival) and PFI (Progress Free Interval). Multivariate analysis showed that POLG2 might be an independent prognostic factor of prostate cancer. We also performed GO/KEGG, GSEA analysis, co-expression genes, and PPI, and observed the metabolism-related gene alterations in PCa. Furthermore, we verified that POLG2 knockdown had an inhibitory effect on mitochondrial function, proliferation, cell motility, and invasion, we affirmed POLG2 could affect the prognosis of advanced prostate cancer via EMT. In summary, our findings indicate that over-expressed POLG2 renders poor prognosis in advanced prostate cancer. This disadvantageous factor can serve as a potential indicator, making it possible to target mitochondrial metabolism to treat advanced prostate cancer.

Apoptin Inhibits Glycolysis and Regulates Autophagy by Targeting Pyruvate Kinase M2 (PKM2) in Lung Cancer A549 Cells.

Pyruvate kinase M2 (PKM2) is a key enzyme in aerobic glycolysis and plays an important role in tumor energy metabolism and tumor growth. Ad-apoptin, a recombinant oncolytic adenovirus, can stably express apoptin in tumor cells and selectively causes cell death in tumor cells. The relationship between the anti-tumor function of apoptin, including apoptosis and autophagy activation, and the energy metabolism of tumor cells has not been clarified. In this study, we used the A549 lung cancer cell line to analyze the mechanism of PKM2 involvement in apoptin-mediated cell death in tumor cells. PKM2 expression in lung cancer cells was detected by Western blot and qRT-PCR. In the PKM2 knockdown and over-expression experiments, A549 lung cancer cells were treated with Ad-apoptin, and cell viability was determined by the CCK-8 assay and crystal violet staining. Glycolysis was investigated using glucose consumption and lactate production experiments. Moreover, the effects of Ad-apoptin on autophagy and apoptosis were analyzed by immunofluorescence using the Annexin v-mCherry staining and by western blot for c-PARP, p62, and LC3-II proteins. Immunoprecipitation analysis was used to investigate the interaction between apoptin and PKM2. In addition, following PKM2 knockdown and overexpression, the expression levels of p-AMPK, p-mTOR, p-ULK1, and p-4E-BP1 proteins in Ad-apoptin treated tumor cells were analyzed by western blot to investigate the mechanism of apoptin effect on the energy metabolism of tumor cells. The in vivo antitumor mechanism of apoptin was analyzed by xenograft tumor inhibition experiment in nude mice and immunohistochemistry of tumors' tissue. As a result, apoptin could target PKM2, inhibit glycolysis and cell proliferation in A549 cells, and promote autophagy and apoptosis in A549 cells by regulating the PKM2/AMPK/mTOR pathway. This study confirmed the necessary role of Ad-apoptin in the energy metabolism of A549 cells.

Abstract 2887: Impact of ionizing radiation on the energy metabolism of normal and tumor cells in the brain

Abstract This study aims to analyze irradiation-induced metabolic alterations in glioblastoma cells and astrocytes to enhance understanding of cellular responses and facilitate the development of more effective radiotherapeutic strategies. Metabolic reprogramming of tumor cells is considered one of the hallmarks of cancer. Studies have shown that abnormal activation of oncogenes and cancer-related signaling pathways, as well as the inactivation of tumor suppressor genes can induce metabolic reprogramming. These metabolic aberrations facilitate rapid proliferation, continuous growth, invasion, metastasis, and immune evasion. Following the application of radiotherapy, the activity of several metabolic pathways significantly changes, potentially leading to the development of radioresistance. However, a differential effect of ionizing radiation on tumor and normal cells is not well understood. Hence, quantifying irradiation-induced metabolic changes in glioblastoma cells and astrocytes is of high importance. We have developed a novel approach to measure dynamic metabolite changes upon irradiation, in vivo, in situ, and in real-time. This tool combines imaging of recently developed fluorescent biosensors via 2-photon microscopy and millimeter-scaled irradiation. Murine glioblastoma cells and astrocytes were generated with stable expression of biosensors for the quantification of intracellular concentrations of various metabolites, including lactate. Cytosolic concentrations of lactate depend on the balance between glycolytic production, mitochondrial consumption of pyruvate and lactate, and the exchange with the extracellular lactate pool via monocarboxylate transporters. Many cancer cells are characterized by an excessive conversion of glucose to lactate even under normoxic conditions. We quantified this so-called Warburg Effect in glioblastoma cells and astrocytes as the ratio between basal lactate production and the lactate increase after OXPHOS inhibition and determined irradiation-induced metabolic changes on the single-cell level. Complementarily, we used metabolomics and Seahorse analyses before and after irradiation. Our data indicate that irradiation increases oxygen consumption in glioblastoma cells but not in astrocytes. Also, we established an orthotopic glioblastoma mouse model via injection of sensor-expressing tumor cells for in vivo measurements of metabolite changes during and after irradiation. These data are expected to significantly advance the understanding of the cellular response to irradiation on a molecular level in situ and in real-time. This knowledge will help to develop combination treatments and increase the efficiency of radiotherapy. Citation Format: Marvin Kreuzer, Pascal Imseng, Bruno Weber, Martin Pruschy. Impact of ionizing radiation on the energy metabolism of normal and tumor cells in the brain [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2887.

ERK5 Interacts with Mitochondrial Glutaminase and Regulates Its Expression.

Many of the biological processes of the cell, from its structure to signal transduction, involve protein-protein interactions. On this basis, our aim was to identify cellular proteins that interact with ERK5, a serine/threonine protein kinase with a key role in tumor genesis and progression and a promising therapeutic target in many tumor types. Using affinity chromatography, immunoprecipitation, and mass spectrometry techniques, we unveiled an interaction between ERK5 and the mitochondrial glutaminase GLS in pancreatic tumor cells. Subsequent co-immunoprecipitation and immunofluorescence studies supported this interaction in breast and lung tumor cells as well. Genetic approaches using RNA interference techniques and CRISPR/Cas9 technology demonstrated that the loss of ERK5 function led to increased protein levels of GLS isoforms (KGA/GAC) and a concomitant increase in their activity in tumor cells. It is well known that the tumor cell reprograms its intermediary metabolism to meet its increased metabolic needs. In this sense, mitochondrial GLS is involved in the first step of glutamine catabolism, one of the main energy sources in the context of cancer. Our data suggest that ERK5 contributes to the regulation of tumor cell energy metabolism via glutaminolysis.

Enhanced photodynamic therapy through multienzyme-like MOF for cancer treatment.

Overcoming resistance to apoptosis is a major challenge in cancer therapy. Recent research has shown that manipulating mitochondria, the organelles critical for energy metabolism in tumor cells, can increase the effectiveness of photodynamic therapy and trigger apoptosis in tumor cells. However, there is currently insufficient research and effective methods to exploit mitochondrial damage to induce apoptosis in tumor cells and improve the effectiveness of photodynamic therapy. In this study, we present a novel nanomedicine delivery and therapeutic system called PyroFPSH, which utilizes a nanozymes-modified metal-organic framework as a carrier. PyroFPSH exhibits remarkable multienzyme-like activities, including glutathione peroxidase (GPx) and catalase (CAT) mimicry, allowing it to overcome apoptosis resistance, reduce endogenous glutathione levels, and continuously generate reactive oxygen species (ROS). In addition, PyroFPSH can serve as a carrier for the targeted delivery of sulfasalazine, a drug that can induce mitochondrial depolarization in tumor cells, thereby reducing oxygen consumption and energy supply in the mitochondria of tumor cells and weakening resistance to other synergistic treatment approaches. Our experimental results highlight the potential of PyroFPSH as a versatile nanoplatform in cancer treatment. This study expands the biomedical applications of nanomaterials as platforms and enables the integration of various novel therapeutic strategies to synergistically improve tumor therapy. It deepens our understanding of multienzyme-mimicking active nanocarriers and mitochondrial damage through photodynamic therapy. Future research can further explore the potential of PyroFPSH in clinical cancer treatment and improve its drug loading capacity, biocompatibility and targeting specificity. In summary, PyroFPSH represents a promising therapeutic approach that can provide new insights and possibilities for cancer treatment.

Oncolytic Virotherapy: A New Paradigm in Cancer Immunotherapy.

Oncolytic viruses (OVs) are emerging as potential treatment options for cancer. Natural and genetically engineered viruses exhibit various antitumor mechanisms. OVs act by direct cytolysis, the potentiation of the immune system through antigen release, and the activation of inflammatory responses or indirectly by interference with different types of elements in the tumor microenvironment, modification of energy metabolism in tumor cells, and antiangiogenic action. The action of OVs is pleiotropic, and they show varied interactions with the host and tumor cells. An important impediment in oncolytic virotherapy is the journey of the virus into the tumor cells and the possibility of its binding to different biological and nonbiological vectors. OVs have been demonstrated to eliminate cancer cells that are resistant to standard treatments in many clinical trials for various cancers (melanoma, lung, and hepatic); however, there are several elements of resistance to the action of viruses per se. Therefore, it is necessary to evaluate the combination of OVs with other standard treatment modalities, such as chemotherapy, immunotherapy, targeted therapies, and cellular therapies, to increase the response rate. This review provides a comprehensive update on OVs, their use in oncolytic virotherapy, and the future prospects of this therapy alongside the standard therapies currently used in cancer treatment.

Hypoxia-induced SHMT2 protein lactylation facilitates glycolysis and stemness of esophageal cancer cells.

Esophageal cancer (EC) is a familiar digestive tract tumor with highly lethal. The hypoxic environment has been demonstrated to be a significant factor in modulating malignant tumor progression and is strongly associated with the abnormal energy metabolism of tumor cells. Serine hydroxymethyl transferase 2 (SHMT2) is one of the most frequently expressed metabolic enzymes in human malignancies. The study was designed to investigate the biological functions and regulation mechanisms of SHMT2 in EC under hypoxia. We conducted RT-qPCR to assess SHMT2 levels in EC tissues and cells (TE-1 and EC109). EC cells were incubated under normoxia and hypoxia, respectively, and altered SHMT2 expression was evaluated through RT-qPCR, western blot, and immunofluorescence. The biological functions of SHMT2 on EC cells were monitored by performing CCK-8, EdU, transwell, sphere formation, glucose uptake, and lactate production assays. The SHMT2 protein lactylation was measured by immunoprecipitation and western blot. In addition, SHMT2-interacting proteins were analyzed by bioinformatics and validated by rescue experiments. SHMT2 was notably upregulated in EC tissues and cells. Hypoxia elevated SHMT2 protein expression, augmenting EC cell proliferation, migration, invasion, stemness, and glycolysis. In addition, hypoxia triggered lactylation of the SHMT2 protein and enhanced its stability. SHMT2 knockdown impeded the malignant phenotype of EC cells. Further mechanistic studies disclosed that SHMT2 is involved in EC progression by interacting with MTHFD1L. Hypoxia-induced SHMT2 protein lactylation and upregulated its protein level, which in turn enhanced MTHFD1L expression and accelerated the malignant progression of EC cells.

An engineered nanoplatform inhibiting energy metabolism and lysosomal activity of tumor cells to multiply cisplatin-based chemotherapy

Although inhibiting the energy metabolism of tumor cells has become an effective measure to enhance chemotherapy, tumor cells can still escape the lethal effect of chemotherapy by entering a dormancy state with low-energy expenditure. Herein, the glutathione (GSH)-responsive nanoplatform (C-A-D NPs) were constructed to inhibit energy metabolism and lysosomal activity of tumor cells, thereby forcing tumor cells to remain vulnerable to cisplatin. In this system, cisplatin prodrug was reduced to cisplatin by GSH, and D-peptide and apoptozole (Az) were released to inhibit the energy metabolism and autophagy-lysosome pathway of tumor cells. The suppressed autophagy-lysosome pathway prevents tumor cells from entering a low-energy dormancy state, resulting in the loss of resistance to the lethal effect of cisplatin with high-energy expenditure and insufficient energy supply. Such engineered nanoplatform effectively enhances the chemotherapeutic effect of cisplatin by inhibiting intracellular energy metabolism and lysosomal activity, showing great clinical prospects.

Chemotranscriptomic analysis of 7-hydroxymatairesinol-related effects on MCF7 human breast tumor cells

Introduction. Establishing the effects of anticancer drugs on the transcriptome is an important procedure in postgenomic pharmacology necessary to comprehensively assess the desired and undesirable effects of candidate drugs. Aim: to assess the effects of lignan 7-hydroxymatairesinol (7HMR) on breast tumor cells.Materials and Methods. Chemotranscriptome profiling was carried out in MCF7 cells (breast cancer cell line) after 24-hour incubation with 7HMR. The GEO (Gene Expression Omnibus) database contains samples of data from transcriptomic studies allowing to model dose-dependent compound-related effects on gene expression based on the chemograph-derived combinatorial analysis algorithms. As a result, a panel of genes with altered expression is generated, which are analyzed by the functional linkage method using the international nomenclature of Gene Ontology (GO) linked to biological roles of genes/proteins.Results. Dose-dependent effects of 7HMR on gene transcription (change in transcription by 5 % or more per 1 μmol 7HMR) were established for 3,468 out of 12,700 genes studied. 7HMR significantly reduced the expression of genes involved in maintaining cell proliferation (401 genes including those involved in telomere maintenance), protein synthesis (194 genes) and proteasomal protein degradation (70 genes), energy metabolism in tumor cells (91 genes) and chronic inflammation (148 genes). A decline in the expression of such gene groups retards the processes of proliferation and vital activity along with protecting host body from excessive inflammation. 7HMR contributed to a predominant increase in the transcription of gene groups involved in antitumor activity (more than 100 genes), including the genes involved in maintaining antitumor immunity as well as those mediating the antitumor effects of vitamin D, retinoids, and vitamin C.Conclusion. The revealed changes in gene transcription enhance 7HMR-related effects on proteome proteins and suggest the prospects for using 7HMR for effective and safe prevention and treatment of nodular mastopathy and breast cancer.

Research Progress of Metformin in the Treatment of Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies with high mortality, posing a great threat to both human physical and mental health. With the advancement of scientific research, a variety of cancer therapies have been used for OSCC treatment. However, the prognosis of OSCC shows no significant improvement. Metformin has been recognized as the first-line drug for the treatment of diabetes, and recent studies have shown that metformin has a remarkable suppressive effect on tumor progression. Metformin can not only affect the energy metabolism of tumor cells but also play an anti-tumor role by modulating the tumor microenvironment and cancer stem cells. In this review, the molecular mechanism of metformin and its anti-cancer mechanism in OSCC are summarized. In addition, this article also summarizes the side effects of metformin and the future prospects of its application in the treatment of OSCC.

Exploring the safety and efficacy of phytomedicine Petiveria alliacea extract (Esperanza) in patients with metastatic gastrointestinal tumors and acute leukemias: study protocol for a phase Ib/randomized double blind phase II trial (PA001)

BackgroundThe energy metabolism of drug-resistant tumor cells can provide a survival advantage during therapy, and treatment itself may influence metabolic reprogramming. Petiveria alliacea (Traditional name: Anamu) could inhibit glycolysis and OXPHOX modulating tumor metabolism, making it a potential treatment for tumors with altered metabolism. This clinical study aims to evaluate the safety and efficacy of a standardized Anamu phytomedicine called Esperanza in treating gastric tumors and acute leukemias.MethodsThis is a prospective, open label, phase I/ randomized, double-blind single-center phase II study designed to evaluate the safety and efficacy of Esperanza extract in patients with metastatic gastrointestinal tumors and acute leukemias. In stage 1, the study will determine the MTD and assess safety. In stage 2, safety at the MTD will be evaluated, and the efficacy of Esperanza extract will be explored in both metastatic gastric tumors and acute leukemias. Quality of life improvement will be the primary outcome in the gastric tumor group, while different efficacy outcomes will be assessed in the acute leukemia group. A placebo group will be used for comparison in the gastric tumor group, and a historical control group will be used in the acute leukemia arm.DiscussionThis clinical trial aims to evaluate the safety profile of the Esperanza extract in patients with metastatic gastrointestinal tumors and acute leukemias, while exploring its potential efficacy in conjunction with standard treatment for these pathologies.Trial registrationThis trial was registered in the US National Library of Medicine with identifier NCT05587088. Registered October 19th, 2022.

Preclinical evaluation of Mito-LND, a targeting mitochondrial metabolism inhibitor, for glioblastoma treatment

BackgroundGlioblastoma (GBM) is a brain tumor with the highest level of malignancy and the worst prognosis in the central nervous system. Mitochondrial metabolism plays a vital role in the occurrence and development of cancer, which provides critical substances to support tumor anabolism. Mito-LND is a novel small-molecule inhibitor that can selectively inhibit the energy metabolism of tumor cells. However, the therapeutic effect of Mito-LND on GBM remains unclear.MethodsThe present study evaluated the inhibitory effect of Mito-LND on the growth of GBM cells and elucidated its potential mechanism.ResultsThe results showed that Mito-LND could inhibit the survival, proliferation and colony formation of GBM cells. Moreover, Mito-LND induced cell cycle arrest and apoptosis. Mechanistically, Mito-LND inhibited the activity of mitochondrial respiratory chain complex I and reduced mitochondrial membrane potential, thus promoting ROS generation. Importantly, Mito-LND could inhibit the malignant proliferation of GBM by blocking the Raf/MEK/ERK signaling pathway. In vivo experiments showed that Mito-LND inhibited the growth of GBM xenografts in mice and significantly prolonged the survival time of tumor-bearing mice.ConclusionTaken together, the current findings support that targeting mitochondrial metabolism may be as a potential and promising strategy for GBM therapy, which will lay the theoretical foundation for further clinical trials on Mito-LND in the future.

Anti-tumor effects of novel alkannin derivatives with potent selectivity on comprehensive analysis

BackgroundTherapeutic approaches based on glycolysis and energy metabolism of tumor cells are new promising strategies for the treatment of cancer. Currently, researches on the inhibition of pyruvate kinase M2, a key rate limiting enzyme in glycolysis, have been corroborated as an effective cancer therapy. Alkannin is a potent pyruvate kinase M2 inhibitor. However, its non-selective cytotoxicity has affected its subsequent clinical application. Thus, it needs to be structurally modified to develop novel derivatives with high selectivity. PurposeOur study aimed to ameliorate the toxicity of alkannin through structural modification and elucidate the mechanism of the superior derivative 23 in lung cancer therapy. MethodsOn the basis of the principle of collocation, different amino acids and oxygen-containing heterocycles were introduced into the hydroxyl group of the alkannin side chain. We examined the cell viability of all derivatives on three tumor cells (HepG2, A549 and HCT116) and two normal cells (L02 and MDCK) by MTT assay. Besides, the effect of derivative 23 on the morphology of A549 cells as observed by Giemsa and DAPI staining, respectively. Flow cytometry was performed to assess the effects of derivative 23 on apoptosis and cell cycle arrest. To further assess the effect of derivative 23 on the Pyruvate kinase M2 in glycolysis, an enzyme activity assay and western blot assay were performed. Finally, in vivo the antitumor activity and safety of the derivative 23 were evaluated by using Lewis mouse lung cancer xenograft model. ResultsTwenty-three novel alkannin derivatives were designed and synthesized to improve the cytotoxicity selectivity. Among these derivatives, derivative 23 showed the highest cytotoxicity selectivity between cancer and normal cells. The anti-proliferative activity of derivative 23 on A549 cells (IC50 = 1.67 ± 0.34 μM) was 10-fold higher than L02 cells (IC50 = 16.77 ± 1.44 μM) and 5-fold higher than MDCK cells (IC50 = 9.23 ± 0.29 μM) respectively. Subsequently, fluorescent staining and flow cytometric analysis showed that derivative 23 was able to induce apoptosis of A549 cells and arrest the cell cycle in the G0/G1 phase. In addition, the mechanistic studies suggested derivative 23 was an inhibitor of pyruvate kinase; it could regulate glycolysis by inhibiting the activation of the phosphorylation of PKM2/STAT3 signaling pathway. Furthermore, studies in vivo demonstrated derivative 23 significantly inhibited the growth of xenograft tumor. ConclusionIn this study, alkannin selectivity is reported to be significantly improved following structural modification, and derivative 23 is first shown to be able to inhibit lung cancer growth via the PKM2/STAT3 phosphorylation signaling pathway in vitro, indicating the potential value of derivative 23 in treating lung cancer.

Precise Starving Therapy via Physiologically Dependent Photothermal Conversion Promoted Mitochondrial Calcification Based on Multi‐Functional Gold Nanoparticles for Effective Tumor Treatment

AbstractStarving therapy based on tumor calcification has been considered as a promising strategy with high biosafety for tumor treatment. However, the limited calcium (Ca2+) concentration in/around tumor tissue as well as the slow and uncontrollable process of the physiological calcification are all challenges for its application. Herein, a sialic acid (SA, Ca2+ chelator), folic acid (FA, tumor targeting agent) and triphenylphosphine (TPP, mitochondrial targeting agent) co‐modified gold nanoparticles (SFT‐Au) are fabricated to take advantage of the abundant Ca2+ in mitochondria as well as the Ca2+ collection and Ca2+ dependent photothermal property of SFT‐Au to achieve a precise and promoted calcification of tumor mitochondria for effective starving therapy. During therapy, the SFT‐Au will first accumulate in tumor mitochondria through stepwise targeting processes medicated by FA and TPP. After that, the SA further binds with the over‐expressed Ca2+ in tumor mitochondria to induce the aggregation of SFT‐Au, which not only gathers Ca2+ to initiate the calcification of mitochondria, but in situ generates photothermal agent to perform photothermal conversion under 808 nm irradiation to promote the calcification, resulting in effective prohibition of the energy metabolism in tumor cells for starving therapy and continuously photothermal damage of tumor cells to enhance the therapeutic efficiency.

U3 snoRNA-mediated degradation of ZBTB7A regulates aerobic glycolysis in isocitrate dehydrogenase 1 wild-type glioblastoma cells.

The isocitrate dehydrogenase (IDH) phenotype is associated with reprogrammed energy metabolism in glioblastoma (GBM) cells. Small nucleolar RNAs (snoRNAs) are known to exert an important regulatory role in the energy metabolism of tumor cells. The purpose of this study was to investigate the role of C/D box snoRNA U3 and transcription factor zinc finger and BTB domain-containing 7A (ZBTB7A) in the regulation of aerobic glycolysis and the proliferative capacity of IDH1 wild-type (IDH1WT ) GBM cells. Quantitative reverse transcription PCR and western blot assays were utilized to detect snoRNA U3 and ZBTB7A expression. U3 promoter methylation status was analyzed via bisulfite sequencing and methylation-specific PCR. Seahorse XF glycolysis stress assays, lactate production and glucose consumption measurement assays, and cell viability assays were utilized to detect glycolysis and proliferation of IDH1WT GBM cells. We found that hypomethylation of the CpG island in the promoter region of U3 led to the upregulation of U3 expression in IDH1WT GBM cells, and the knockdown of U3 suppressed aerobic glycolysis and the proliferation ability of IDH1WT GBM cells. We found that small nucleolar-derived RNA (sdRNA) U3-miR, a small fragment produced by U3, was able to bind to the ZBTB4 3'UTR region and reduce ZBTB7A mRNA stability, thereby downregulating ZBTB7A protein expression. Furthermore, ZBTB7A transcriptionally inhibited the expression of hexokinase 2 (HK2) and lactate dehydrogenase A (LDHA), which are key enzymes of aerobic glycolysis, by directly binding to the HK2 and LDHA promoter regions, thereby forming the U3/ZBTB7A/HK2 LDHA pathway that regulates aerobic glycolysis and proliferation of IDH1WT GBM cells. U3 enhances aerobic glycolysis and proliferation in IDH1WT GBM cells via the U3/ZBTB7A/HK2 LDHA axis.

Abstract 5117: Combined treatment with the epigenetic drug CM272 and an anti-BCL-XL proapoptotic drug sensitizes solid tumors to immune checkpoint blockade

Abstract Epigenetic modulators in combination with proapoptotic drugs have become a standard of treatment for acute myeloid leukemia. However, the clinical efficacy of these combinations in solid tumors has shown to be negligible. Our group has demonstrated that the epigenetic drug CM272, which targets DNMT and G9a, induces synergistic responses in combination with proapoptotic drugs in hematological malignancies (Cancer Discovery 2021). We have also reported that CM272 induces an immunogenic cell death that sensitizes tumor cells to immune checkpoint blockade (ICB) (Nature Medicine 2020). Here, we hypothesized that CM272 in combination with proapoptotic drugs may sensitize tumor cells to ICB, resulting in profound anti-tumor responses. To test this hypothesis, we evaluated in vitro the sensitivity of cancer cells to different combinations of epigenetic and proapoptotic drugs. The most efficient combination was tested in various immunocompetent mouse models, followed by an immunophenotypic characterization of the tumor microenvironment. We found that CM272 in combination with inhibitors of BCL-XL, BCL2 or MCL1, yielded synergistic in vitro responses in a large collection of human and mouse cell lines derived from solid tumors. Mechanistically, the treatments induced the expression of endogenous retroelements/retroviruses, which led to the activation of RIG-1 and MDA5 viral sensors, ATP hydrolysis and tumor cell death. Remarkably, we found that CM272 in combination with BCL-XL inhibition had more potent anti-tumor effects than that found with BCL2 or MCL1 inhibitors. In vivo, the triple combination CM272, A1331852 (BCL-XL inhibitor) and an anti-PD-1 moAb significantly reduced tumor growth and increased overall survival in three subcutaneous lung cancer models (LLC, 393P, Lacun-3) in comparison to double treatments. Moreover, this triple combination also induced significant anti-tumor responses in subcutaneous mouse models of colon cancer (MC38) and melanoma (B16), as well as in orthotopic models of lung cancer (LLC), glioblastoma (CT-2A) and breast cancer (ANV5), leading to prolonged survival and cure in a fraction of animals. The triple therapy was associated with a significant increase in the ratio of CD8 T versus immunosuppressive Treg cells, and M1 versus M2 macrophages. In conclusion, we report a novel regimen combining a dual epigenetic inhibitor, an anti-BCL-XL, and an anti-PD-1 moAb that results in potent responses in multiple pre-clinical models of solid tumors. The mechanisms underneath the antitumor responses include the modulation of the energy metabolism in tumor cells, leading to cell death boosted by an anti-BCL-XL pro-apoptotic drug, along with fostering the immune system to generate an efficient anti-tumor response assisted by ICB. This study reveals the potential of epigenetic therapeutics to treat and cure patients with solid tumors. Citation Format: Yaiza Senent, Vicente Fresquet, Victoria Jimenez, Karmele Valencia, Ana Remirez, Francisco Exposito, Marisol Gonzalez-Huarriz, Borja Ruiz-Fernandez de Cordoba, Haritz Moreno, Daniel Ajona, Marta M Alonso, Fernando Lecanda, Antonio Pineda-Lucena, Felipe Prosper, Alfonso Calvo, Jose Angel Martinez-Climent, Ruben Pio. Combined treatment with the epigenetic drug CM272 and an anti-BCL-XL proapoptotic drug sensitizes solid tumors to immune checkpoint blockade. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5117.

Emerging role of substance and energy metabolism associated with neuroendocrine regulation in tumor cells.

Cancer is the second most common cause of mortality in the world. One of the unresolved difficult pathological mechanism issues in malignant tumors is the imbalance of substance and energy metabolism of tumor cells. Cells maintain life through energy metabolism, and normal cells provide energy through mitochondrial oxidative phosphorylation to generate ATP, while tumor cells demonstrate different energy metabolism. Neuroendocrine control is crucial for tumor cells' consumption of nutrients and energy. As a result, better combinatorial therapeutic approaches will be made possible by knowing the neuroendocrine regulating mechanism of how the neuroendocrine system can fuel cellular metabolism. Here, the basics of metabolic remodeling in tumor cells for nutrients and metabolites are presented, showing how the neuroendocrine system regulates substance and energy metabolic pathways to satisfy tumor cell proliferation and survival requirements. In this context, targeting neuroendocrine regulatory pathways in tumor cell metabolism can beneficially enhance or temper tumor cell metabolism and serve as promising alternatives to available treatments.

NIR-II Imaging-Guided Mitochondrial-Targeting Organic Nanoparticles for Multimodal Synergistic Tumor Therapy.

Effectively interfering energy metabolism in tumor cells and simultaneously activating the in vivo immune system to perform immune attacks are meaningful for tumor treatment. However, precisely targeted therapy is still a huge challenge. Herein, a mitochondrial-targeting phototheranostic system, FE-T nanoparticles (FE-T NPs) are developed to damage mitochondria in tumor cells and change the tumor immunosuppressive microenvironment. FE-T NPs are engineered by encapsulating the near-infrared (NIR) absorbed photosensitizer IR-FE-TPP within amphiphilic copolymer DSPE-SS-PEG-COOH for high-performing with simultaneous mitochondrial-targeting, near-infrared II (NIR-II) fluorescence imaging, and synchronous photothermal therapy (PTT) /photodynamic therapy (PDT) /immune therapy (IMT). In tumor treatment, the disulfide in the copolymer can be cleaved by excess intracellular glutathione (GSH) to release IR-FE-TPP and accumulate in mitochondria. After 808nm irradiation, the mitochondrial localization of FE-T NPs generated reactive oxygen species (ROS), and hyperthermia, leading to mitochondrial dysfunction, photoinductive apoptosis, and immunogenic cell death (ICD). Notably, in situ enhanced PDT/PTT in vivo via mitochondrial-targeting with FE-T NPs boosts highly efficient ICD toward excellent antitumor immune response. FE-T NPs provide an effective mitochondrial-targeting phototheranostic nanoplatform for imaging-guided tumor therapy.

Friend or Foe: Regulation, Downstream Effectors of RRAD in Cancer.

Ras-related associated with diabetes (RRAD), a member of the Ras-related GTPase superfamily, is primarily a cytosolic protein that actives in the plasma membrane. RRAD is highly expressed in type 2 diabetes patients and as a biomarker of congestive heart failure. Mounting evidence showed that RRAD is important for the progression and metastasis of tumor cells, which play opposite roles as an oncogene or tumor suppressor gene depending on cancer and cell type. These findings are of great significance, especially given that relevant molecular mechanisms are being discovered. Being regulated in various pathways, RRAD plays wide spectrum cellular activity including tumor cell division, motility, apoptosis, and energy metabolism by modulating tumor-related gene expression and interacting with multiple downstream effectors. Additionally, RRAD in senescence may contribute to its role in cancer. Despite the twofold characters of RRAD, targeted therapies are becoming a potential therapeutic strategy to combat cancers. This review will discuss the dual identity of RRAD in specific cancer type, provides an overview of the regulation and downstream effectors of RRAD to offer valuable insights for readers, explore the intracellular role of RRAD in cancer, and give a reference for future mechanistic studies.