Hexokinase 2 is required for tumor initiation and maintenance and its systemic deletion is therapeutic in mouse models of cancer

Hexokinase II expression as a prognostic marker in diffuse large B-cell lymphoma: pre- and post-rituximab era

We aimed to assess HKII expression and its prognostic significance in diffuse large B-cell lymphoma (DLBCL) patients. The HKII protein level was determined by immunohistochemistry in 159 newly diagnosed DLBCL patients, and its relationship with overall response rate, progression-free survival (PFS), and overall survival (OS) was analyzed. HKII was expressed in 95 DLBCL patients (59.7%). HKII-positive patients had poorer outcomes than negative patients for 5-y PFS (68% vs. 84%, p = 0.029) and 5-y OS (78% vs. 94%, p = 0.05). When only patients without no bulky disease, B symptoms, or extranodal involvement who had low IPI scores were considered, those with positive HKII had worse 5y-PFS and 5y-OS (p < 0.05). Multivariate analysis indicated that HKII status was an independent prognostic factor of OS. In subgroup analysis, HKII expression was associated with inferior OS in the CHOP group (p = 0.017). In CHOP group patients without bulky disease or extranodal involvement who had low LDH and low IPI scores (p < 0.05), positive HKII was associated with worse PFS and OS. No differences in PFS and OS, or any independent prognostic factors, were found in the RCHOP group. In DLBCL, HKII is valuable as a prognostic biomarker and may be useful as a tool for assessing disease risk.

Sodium butyrate inhibits aerobic glycolysis of hepatocellular carcinoma cells via the c-myc/hexokinase 2 pathway

Aerobic glycolysis is a well-known hallmark of hepatocellular carcinoma (HCC). Hence, targeting the key enzymes of this pathway is considered a novel approach to HCC treatment. The effects of sodium butyrate (NaBu), a sodium salt of the short-chain fatty acid butyrate, on aerobic glycolysis in HCC cells and the underlying mechanism are unknown. In the present study, data obtained from cell lines with mouse xenograft model revealed that NaBu inhibited aerobic glycolysis in the HCC cells in vivo and in vitro. NaBu induced apoptosis while inhibiting the proliferation of the HCC cells in vivo and in vitro. Furthermore, the compound inhibited the release of lactate and glucose consumption in the HCC cells in vitro and inhibited the production of lactate in vivo. The modulatory effects of NaBu on glycolysis, proliferation and apoptosis were related to its modulation of hexokinase 2 (HK2). NaBu downregulated HK2 expression via c-myc signalling. The upregulation of glycolysis in the HCC cells induced by sorafenib was impeded by NaBu, thereby enhancing the anti-HCC effect of sorafenib in vitro and in vivo. Thus, NaBu inhibits the expression of HK2 to downregulate aerobic glycolysis and the proliferation of HCC cells and induces their apoptosis via the c-myc pathway.

The influence of antioxidant dietary-derived polyphenolic combination on breast cancer: Molecular study

Breast cancer remains a leading cause of female mortality worldwide. Therefore, novel complementary treatments have been sought. Recently, there has been a growing interest in investigating the possible complementary effects of polyphenolic compounds against various malignancies. In the present study, using MCF-7 and MDA-MB-231 human breast adenocarcinoma cells, the anticancer efficacy of a polyphenolic mixture (PFM) was investigated. PFM is composed of curcumin, resveratrol, epigallocatechin gallate, and quercetin. PFM treatment led to a dose-dependent inhibition of cell proliferation, with IC₅₀ values of 25.9 ± 3 µg/ml and 29.4 ± 0.9 µg/ml for MCF-7 and MDA-MB-231 cells, respectively. In addition, PFM induced apoptosis in MDA-MB-231 cells and cell cycle arrest at the S phase in MCF-7 cells. Using RT-qPCR, PFM treatment was observed to result in significant downregulation of the oncogenic miR-155 (P < 0.05), as well as significant downregulation of the rate-limiting glycolytic enzyme, hexokinase 2 (HK2) (P < 0.05), while upregulating the expression of the zinc finger E-box binding homeobox 2 gene (P < 0.01). PFM was also found to exert an anti-migration effect in breast cancer cells using the wound healing assay, as well as significantly (P < 0.05) increasing the median survival of Ehrlich ascites carcinoma (EAC) tumor-bearing mice. These results suggest that PFM possesses potential antitumor effects against breast cancer. A possible mechanism of action could be due to PFM's effect in modulating the expression of the glycolytic enzyme HK2 through suppression of miR-155 in MCF-7 cells. Combining polyphenolic compounds that interact with one another could result in synergistic effects that potentially target various tumour hallmarks.

Cinnamon bark extract suppresses metastatic dissemination of cancer cells through inhibition of glycolytic metabolism

Metastasis is responsible for approximately 90% of cancer-associated mortality and proceeds through multiple steps. Several herbal medicines are reported to inhibit primary tumor growth, but the suppressor effects of the medicines on metastasis progression are still not fully elucidated. Here we report that cinnamon bark extract (CBE) has a suppressor effect on metastatic dissemination of cancer cells. Through a phenotypic screening using zebrafish embryos, CBE was identified to interfere with the gastrulation progression of zebrafish embryos, of which the molecular mechanisms are conserved in metastasis progression. A Boyden chamber assay showed that CBE decreased cell motility and invasion of MDA-MB-231 human breast cancer cells without affecting their cell viability. Furthermore, CBE suppressed metastatic dissemination of the cells in a zebrafish xenotransplantation model. Quantitative metabolome analyses revealed that the productions of glucose-6-phosphate (G6P) and fructose 6-phosphate which are intermediate metabolites of glycolytic metabolism were interrupted in CBE-treated cells. qPCR and western-blotting analyses revealed that CBE-treated cells showed decreased expression of hexokinase 2 (HK2) which yields G6P. Pharmacological inhibition of HK2 with 2-deoxy-D-glucose suppressed cell invasion and migration of the cells without affecting their cell viability. Taken together, CBE suppresses metastatic dissemination of cancer cells through inhibition of glycolysis metabolism.

NEDD9 sustains hexokinase expression to promote glycolysis

Elevated rates of glycolysis in cancer cells support tumor growth, in a process that typically depends on oncogene-induced increases in the expression and/or activity of enzymes in the glycolytic pathway. The NEDD9 scaffolding protein is upregulated in many advanced tumors, with increased NEDD9 promoting the activity of SRC and other effectors that promote invasion and metastasis. We here define a new role for NEDD9 in support of glycolysis. NEDD9 knockdown significantly impaired glycolysis in multiple lung cancer cell lines This was accompanied by post-transcriptional downregulation of steady-state levels of hexokinases (HK1 and HK2), which catalyze early steps in the glycolytic cascade, key rate limiting enzyme phosphofructokinase (PFK1), and downstream glyceraldehyde phosphate dehydrogenase (GAPDH). In mice, protein levels of HK1, HK2, PFK1, and GAPDH were depressed in Krastm4Tyj/J/Trp53tm1Brn/J (KP) non-small cell lung tumors with null versus wild type Nedd9. Reciprocally, depletion of HK1 or HK2 elevated NEDD9 expression, as did the treatment of cells with 2-deoxyglucose (2DG), an inhibitor of glycolysis; whereas overexpression of hexokinases promoted NEDD9 dephosphorylation, associated with reduced NEDD9 activity. Together, these data for the first time suggest a negative feedback circuit involving NEDD9 and glycolytic enzymes that may contribute to NEDD9 action in promoting the aggressive growth of advanced tumors.

Unravelling similarities and differences in the role of circular and linear PVT1 in cancer and human disease

The plasmacytoma variant translocation 1 (PVT1) is a long non-coding RNA gene involved in human disease, mainly in cancer onset/progression. Although widely analysed, its biological roles need to be further clarified. Notably, functional studies on PVT1 are complicated by the occurrence of multiple transcript variants, linear and circular, which generate technical issues in the experimental procedures used to evaluate its impact on human disease. Among the many PVT1 transcripts, the linear PVT1 (lncPVT1) and the circular hsa_circ_0001821 (circPVT1) are frequently reported to perform similar pathologic and pro-tumorigenic functions when overexpressed. The stimulation of cell proliferation, invasion and drug resistance, cell metabolism regulation, and apoptosis inhibition is controlled through multiple targets, including MYC, p21, STAT3, vimentin, cadherins, the PI3K/AKT, HK2, BCL2, and CASP3. However, some of this evidence may originate from an incorrect evaluation of these transcripts as two separate molecules, as they share the lncPVT1 exon-2 sequence. We here summarise lncPVT1/circPVT1 functions by mainly focusing on shared pathways, pointing out the potential bias that may exist when the biological role of each transcript is analysed. These considerations may improve the knowledge about lncPVT1/circPVT1 and their specific targets, which deserve further studies due to their diagnostic, prognostic, and therapeutic potential.

Histone H2AX promotes metastatic progression by preserving glycolysis via hexokinase-2

Genomic stability is essential for organismal development, cellular homeostasis, and survival. The DNA double-strand breaks are particularly deleterious, creating an environment prone to cellular transformation and oncogenic activation. The histone variant H2AX is an essential component of the nucleosome responsible for initiating the early steps of the DNA repair process. H2AX maintains genomic stability by initiating a signaling cascade that collectively functions to promote DNA double-strand breaks repair. Recent advances have linked genomic stability to energetic metabolism, and alterations in metabolism were found to interfere with genome maintenance. Utilizing genome-wide transcripts profiling to identify differentially-expressed genes involved in energetic metabolism, we compared control and H2AX-deficient metastatic breast cancer cell lines, and found that H2AX loss leads to the repression of key genes regulating glycolysis, with a prominent effect on hexokinase-2 (HK2). These observations are substantiated by evidence that H2AX loss compromises glycolysis, effect which was reversed by ectopic expression of HK2. Utilizing models of experimental metastasis, we found that H2AX silencing halts progression of metastatic breast cancer cells MDA-MB-231. Most interestingly, ectopic expression of HK2 in H2AX-deficient cells restores their metastatic potential. Using multiple publicly available datasets, we found a significantly strong positive correlation between H2AX expression levels in patients with invasive breast cancer, and levels of glycolysis genes, particularly HK2. These observations are consistent with the evidence that high H2AX expression is associated with shorter distant metastasis-free survival. Our findings reveal a role for histone H2AX in controlling the metastatic ability of breast cancer cells via maintenance of HK2-driven glycolysis.

Comprehensive Metabolic Profiling of MYC-Amplified Medulloblastoma Tumors Reveals Key Dependencies on Amino Acid, Tricarboxylic Acid and Hexosamine Pathways

Simple Summary

The oncogene MYC alters cellular metabolism. Medulloblastoma is the most common malignant pediatric brain tumor. MYC-amplified medulloblastoma has a poor prognosis, and the metabolism of MYC-amplified medulloblastoma is poorly understood. We performed comprehensive metabolic profiling of MYC-amplified medulloblastoma and found increased reliance on potentially targetable pathways. We also found that the metabolism of MYC-amplified cell lines differed from orthotopic brain tumors in vitro and in flank tumors, suggesting that analyses conducted in vitro or in flank tumors may miss key vulnerabilities.

Abstract

Reprograming of cellular metabolism is a hallmark of cancer. Altering metabolism allows cancer cells to overcome unfavorable microenvironment conditions and to proliferate and invade. Medulloblastoma is the most common malignant brain tumor of children. Genomic amplification of MYC defines a subset of poor-prognosis medulloblastoma. We performed comprehensive metabolic studies of human MYC-amplified medulloblastoma by comparing the metabolic profiles of tumor cells in three different conditions—in vitro, in flank xenografts and in orthotopic xenografts in the cerebellum. Principal component analysis showed that the metabolic profiles of brain and flank high-MYC medulloblastoma tumors clustered closely together and separated away from normal brain and in vitro MYC-amplified cells. Compared to normal brain, MYC-amplified medulloblastoma orthotopic xenograft tumors showed upregulation of the TCA cycle as well as the synthesis of nucleotides, hexosamines, amino acids and glutathione. There was significantly higher glucose uptake and usage in orthotopic xenograft tumors compared to flank xenograft tumors and cells in culture. In orthotopic tumors, glucose was the main carbon source for the de novo synthesis of glutamate, glutamine and glutathione through the TCA cycle. In vivo, the glutaminase II pathway was the main pathway utilizing glutamine. Glutathione was the most abundant upregulated metabolite in orthotopic tumors compared to normal brain. Glutamine-derived glutathione was synthesized through the glutamine transaminase K (GTK) enzyme in vivo. In conclusion, high MYC medulloblastoma cells have different metabolic profiles in vitro compared to in vivo, and key vulnerabilities may be missed by not performing in vivo metabolic analyses.

The critical function of metabolic reprogramming in cancer metastasis

Cancer metastasis is the leading cause of cancer‐related death. It is a complex, inefficient, and multistep process related to poor prognosis and high mortality of patients. Increasing evidence has shown that metabolic programming is a recognized hallmarker of cancer, plays a critical role in cancer metastasis. Metabolism alterations of glucose, lipid, and amino acid provide cancer cells with energy and substances for biosynthesis, maintain biofunctions and significantly affect proliferation, invasion, and metastasis of cancer cells. Tumor microenvironment (TME) is a complex system formed by varieties of cellular and noncellular elements. Nontumor cells in TME also undergo metabolic reprogramming or respond to metabolites to promote migration and invasion of cancer cells. A comprehensive understanding of the regulatory mechanism in metastasis from the metabolic reprogramming aspect is required to develop new therapeutic strategies combatting cancer metastasis. This review illustrates the metabolic reprogramming and interaction of cancer cells and nontumor cells in the TME, and the development of treatment strategies targeting metabolism alterations.

Targeting the mitochondrial permeability transition pore for drug discovery: Challenges and opportunities

Several drug targets have been amenable to drug discovery pursuit not until the characterization of the mitochondrial permeability transition pore (MPTP), a pore with an undefined molecular identity that forms on the inner mitochondrial membrane upon mitochondrial permeability transition (MPT) under the influence of calcium overload and oxidative stress. The opening of the pore which is presumed to cause cell death in certain human diseases also has implications under physiological parlance. Different models for this pore have been postulated following its first identification in the last six decades. The mitochondrial community has witnessed many protein candidates such as; voltage-dependent anion channel (VDAC), adenine nucleotide translocase (ANT), Mitochondrial phosphate carrier (PiC), Spastic Paralegin (SPG7), disordered proteins, and F1Fo ATPase. However, genetic studies have cast out most of these candidates with only F1Fo ATPase currently under intense argument. Cyclophilin D (CyPD) remains the widely accepted positive regulator of the MPTP known to date, but no drug candidate has emerged as its inhibitor, raising concern issues for therapeutics. Thus, in this review, we discuss various models of MPTP reported with the hope of stimulating further research in this field. We went beyond the classical description of the MPTP to ascribe a 'two-edged sword property' to the pore for therapeutic function in human disease because its inhibition and activation have pharmacological relevance. We suggested putative proteins upstream to CyPD that can regulate its activity and prevent cell deaths in neurodegenerative disease and ischemia-reperfusion injury.

Transcriptomic and Metabolomic Analyses Provide Insights into the Growth and Development Advantages of Triploid Apostichopus japonicus

Polyploid breeding is widely used in aquaculture as an important area of new research. We have previously grown Apostichopus japonicus triploids with a growth advantage. The body length, body weight, and aestivation time of triploid and diploid A. japonicus were measured in this study, and the transcriptome and metabolome were used to examine the growth advantage of triploids A. japonicus. The results showed that the proportion of triploid A. japonicus with a body length of 6-12 cm and 12-18 cm was significantly higher than that of diploid A. japonicus, and triploid A. japonicus had a shorter aestivation time (39 days) than diploid (63 days). We discovered 3296 differentially expressed genes (DEGs); 13 DEGs (for example, cyclin-dependent kinase 2) related to growth advantage, immune regulation, and energy storage were screened as potential candidates. According to Gene Ontology (GO) enrichment analysis, DEGs were significantly enriched in the cytoplasm (cellular component), ATP binding process (molecular function), oxidation-reduction process (biological process), and other pathways. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment data, DEGs were significantly enriched in ribosome production and other areas. We discovered 414 significant differential metabolites (SDMs), with 11 important SDMs (for example, nocodazole) linked to a growth advantage. SDMs are significantly enriched in metabolic pathways, as well as other pathways, according to the KEGG enrichment results. According to a combined transcriptome and metabolome analysis, 6 DEGs have regulatory relationships with 11 SDMs, which act on 11 metabolic pathways together. Our results further enrich the biological data of triploid A. japonicus and provide useful resources for genetic improvement of this species.

The Correlation of HK2 Gene Expression with the Occurrence, Immune Cell Infiltration, and Prognosis of Renal Cell Carcinoma

Objectives

Hexokinase 2 (HK2) is one of the key factors involved in the development of several human cancers. However, its role in immune cell infiltration (ICI) and tumor development in renal cell carcinoma is not yet known. Thus, we aimed to explore its relationship with ICI, overall survival, and prognosis of renal cell carcinoma.

Methods

In this study, RNA-seq data from renal cancer and normal tissues were extracted from TCGA and the relationship between HK2 expression and pathological features of RCC patients was analyzed using the GEPIA and UALCAN databases. Subsequently, Western blot and qRT-PCR were performed to analyze the protein and mRNA expression of HK2 in renal cell carcinoma tissues and cell lines. Lastly, various bioinformatics tools were applied to determine the immune cell infiltration, survival, and developing prediction model.

Results

The analysis of RNA-seq data revealed a high expression of HK2 in renal cell carcinoma; furthermore, Western blot and qRT-PCR also showed high expression of HK2 in renal cancer tissues and cell lines. The high expression of HK2 showed a significant positive correlation with the advanced stage of the tumor, lymph node metastasis, and worst survival in renal carcinoma patients. The high expression of HK2 was further identified as an independent risk factor of RCC patients; it also showed a significant positive immune cell infiltration RCC tumor microenvironment including macrophages, B cells, neutrophils, dendritic cells, and CD8⁺ T cells.

Conclusion

the expression of HK2 is positively correlated with the immune cell infiltration and prognosis of renal cell carcinoma patients, thus playing an important role in renal cancer development.

PI3K-AKT Pathway Modulation by Thymoquinone Limits Tumor Growth and Glycolytic Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of death in men and the fourth in women worldwide and is characterized by deranged cellular energetics. Thymoquinone, an active component from Nigella sativa, has been extensively studied against cancer, however, its role in affecting deregulated cancer metabolism is largely unknown. Further, the phosphoinositide 3-kinase (PI3K) pathway is one of the most activated pathways in cancer and its activation is central to most deregulated metabolic pathways for supporting the anabolic needs of growing cancer cells. Herein, we provide evidence that thymoquinone inhibits glycolytic metabolism (Warburg effect) in colorectal cancer cell lines. Further, we show that such an abrogation of deranged cell metabolism was due, at least in part, to the inhibition of the rate-limiting glycolytic enzyme, Hexokinase 2 (HK2), via modulating the PI3/AKT axis. While overexpression of HK2 showed that it is essential for fueling glycolytic metabolism as well as sustaining tumorigenicity, its pharmacologic and/or genetic inhibition led to a reduction in the observed effects. The results decipher HK2 mediated inhibitory effects of thymoquinone in modulating its glycolytic metabolism and antitumor effects. In conclusion, we provide evidence of metabolic perturbation by thymoquinone in CRC cells, highlighting its potential to be used/repurposed as an antimetabolite drug, though the latter needs further validation utilizing other suitable cell and/or preclinical animal models.

High-throughput glycolytic inhibitor discovery targeting glioblastoma by graphite dots-assisted LDI mass spectrometry

Malignant tumors will become vulnerable if their uncontrolled biosynthesis and energy consumption engaged in metabolic reprogramming can be cut off. Here, we report finding a glycolytic inhibitor targeting glioblastoma with graphite dots-assisted laser desorption/ionization mass spectrometry as an integrated drug screening and pharmacokinetic platform (GLMSD). We have performed high-throughput virtual screening to narrow an initial library of 240,000 compounds down to the docking of 40 compounds and identified five previously unknown chemical scaffolds as promising hexokinase-2 inhibitors. The best inhibitor (Compd 27) can regulate the reprogrammed metabolic pathway in U87 glioma cells (median inhibitory concentration ~ 11.3 μM) for tumor suppression. Highly effective therapy against glioblastoma has been demonstrated in both subcutaneous and orthotopic brain tumors by synergizing Compd 27 and temozolomide. Our glycolytic inhibitor discovery can inspire personalized medicine targeting reprogrammed metabolisms of malignant tumors. GLMSD enables large, high-quality data for next-generation artificial intelligence-aided drug development.

A non-catalytic scaffolding activity of hexokinase 2 contributes to EMT and metastasis

Hexokinase 2 (HK2), which catalyzes the first committed step in glucose metabolism, is induced in cancer cells. HK2's role in tumorigenesis has been attributed to its glucose kinase activity. Here, we describe a kinase independent HK2 activity, which contributes to metastasis. HK2 binds and sequesters glycogen synthase kinase 3 (GSK3) and acts as a scaffold forming a ternary complex with the regulatory subunit of protein kinase A (PRKAR1a) and GSK3β to facilitate GSK3β phosphorylation and inhibition by PKA. Thus, HK2 functions as an A-kinase anchoring protein (AKAP). Phosphorylation by GSK3β targets proteins for degradation. Consistently, HK2 increases the level and stability of GSK3 targets, MCL1, NRF2, and particularly SNAIL. In addition to GSK3 inhibition, HK2 kinase activity mediates SNAIL glycosylation, which prohibits its phosphorylation by GSK3. Finally, in mouse models of breast cancer metastasis, HK2 deficiency decreases SNAIL protein levels and inhibits SNAIL-mediated epithelial mesenchymal transition and metastasis.

RAS-mediated tumor stress adaptation and the targeting opportunities it presents

Cellular stress is known to function in synergistic cooperation with oncogenic mutations during tumorigenesis to drive cancer progression. Oncogenic RAS is a strong inducer of a variety of pro-tumorigenic cellular stresses, and also enhances the ability of cells to tolerate these stresses through multiple mechanisms. Many of these oncogenic, RAS-driven, stress-adaptive mechanisms have also been implicated in tolerance and resistance to chemotherapy and to therapies that target the RAS pathway. Understanding how oncogenic RAS shapes cellular stress adaptation and how this functions in drug resistance is of vital importance for identifying new therapeutic targets and therapeutic combinations to treat RAS-driven cancers.

Methylglyoxal induces ambience for cancer promotion in HepG2 cells via Warburg effect and promotes glycation

Methylglyoxal (MGO) is a toxic, highly reactive metabolite derived mainly from glucose and amino acids degradation. MGO is also one of the prime precursors for advanced glycation end products formation. The present research was performed to check whether MGO has any role in the promotion of cancer in HepG2 cells. For this, cells were incubated with MGO (50 µM) for 24 h and subjected to various analyses. Aminoguanidine (200 µM) was positive control. The various biochemical and protein expression studies, relevant to the MGO detoxification system, oxidative stress, and glycolysis were performed. MGO caused the reduction of expression of GLO 1 (27%) and GLO 2 (11%) causing weakening of the innate detoxification system. This is followed by an increase of RAGE (95%), AGEs or methylglyoxal adducts. We also observed hypoxia via estimation of oxygen consumption rate and surplus reactive oxygen species (ROS) (24%). To investigate the off-target effect of MGO we checked its effect on glucose transport, and its associated proteins. Glucose uptake was found to increase (15%) significantly with overexpression of GLUT 1 (35%). We also found a significant increase of glycolytic enzymes such as hexokinase II, phosphofructokinase 1, and lactate dehydrogenase along with lactate production. Observation of surplus ROS and enhanced glycolysis led us to check the expression of HIF 1α which is their downstream signaling pathway. Interestingly HIF 1α was found to increase significantly (35%). It is known that enhanced glycolysis and oxidative stress are catalysts for the overexpression of HIF 1α which in turn creates an ambience for the promotion of cancer. Aminoguanidine was able to prevent the adverse effect of MGO partially. This is the first study to show the potential of MGO for the promotion of cancer in the non-tumorigenic HepG2 cells via the Warburg effect and glycation.

High Expression of Glycolytic Genes in Clinical Glioblastoma Patients Correlates With Lower Survival

Glioblastoma (GBM), the most aggressive brain tumor, is associated with a median survival at diagnosis of 16–20 months and limited treatment options. The key hallmark of GBM is altered tumor metabolism and marked increase in the rate of glycolysis. Aerobic glycolysis along with elevated glucose consumption and lactate production supports rapid cell proliferation and GBM growth. In this study, we examined the gene expression profile of metabolic targets in GBM samples from patients with lower grade glioma (LGG) and GBM. We found that gene expression of glycolytic enzymes is up-regulated in GBM samples and significantly associated with an elevated risk for developing GBM. Our findings of clinical outcomes showed that GBM patients with high expression of HK2 and PKM2 in the glycolysis related genes and low expression of genes involved in mitochondrial metabolism-SDHB and COX5A related to tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS), respectively, was associated with poor patient overall survival. Surprisingly, expression levels of genes involved in mitochondrial oxidative metabolism are markedly increased in GBM compared to LGG but was lower compared to normal brain. The fact that in GBM the expression levels of TCA cycle and OXPHOS-related genes are higher than those in LGG patients suggests the metabolic shift in GBM cells when progressing from LGG to GBM. These results are an important step forward in our understanding of the role of metabolic reprogramming in glioma as drivers of the tumor and could be potential prognostic targets in GBM therapies.

Cell demise inhibited: Unexpected liaisons between mitochondria and IκΒα

IκΒα (the protein product of NFKBIA gene) has widely been considered a pro- apoptotic factor due to its ability to inhibit the anti-apoptotic transcription factor NFκB. Our findings indicate that IκΒα also exerts a strong anti-apoptotic activity at the outer mitochondria membrane (OMM). This function we uncovered is distinct from its ability to sequester and inhibit NFκB. IκΒα instead binds to voltage dependent anion channel 1 (VDAC1) and Hexokinase 2 (HK2), stabilizes this complex and prevents mitochondria outer membrane permeabilisation (MOMP) and apoptosis.

Pathophysiological Integration of Metabolic Reprogramming in Breast Cancer

Metabolic changes that facilitate tumor growth are one of the hallmarks of cancer. The triggers of these metabolic changes are located in the tumor parenchymal cells, where oncogenic mutations induce an imperative need to proliferate and cause tumor initiation and progression. Cancer cells undergo significant metabolic reorganization during disease progression that is tailored to their energy demands and fluctuating environmental conditions. Oxidative stress plays an essential role as a trigger under such conditions. These metabolic changes are the consequence of the interaction between tumor cells and stromal myofibroblasts. The metabolic changes in tumor cells include protein anabolism and the synthesis of cell membranes and nucleic acids, which all facilitate cell proliferation. They are linked to catabolism and autophagy in stromal myofibroblasts, causing the release of nutrients for the cells of the tumor parenchyma. Metabolic changes lead to an interstitium deficient in nutrients, such as glucose and amino acids, and acidification by lactic acid. Together with hypoxia, they produce functional changes in other cells of the tumor stroma, such as many immune subpopulations and endothelial cells, which lead to tumor growth. Thus, immune cells favor tissue growth through changes in immunosuppression. This review considers some of the metabolic changes described in breast cancer.

Mannose enhances the radio-sensitivity of esophageal squamous cell carcinoma with low MPI expression by suppressing glycolysis

BACKGROUND

To investigate the effect of mannose on radio-sensitivity of human esophageal squamous cell carcinoma (ESCC) cell line and its possible mechanism.

METHODS

The expression of mannose phosphate isomerase (MPI) in human esophageal cancer cell lines were detected by Western blot. The inhibitory effect of mannose on human esophageal cancer cell lines were observed by MTT assay. Plate clone formation assay was performed to investigate the efficacy of mannose on radio-sensitivity of human esophageal cancer cells. The apoptosis rates of tumor cells treated with mannose and/or radiation therapy was calculated by flow cytometry. Furthermore, we analyzed intracellular metabolites using liquid chromatography mass spectrometry to identify selective sugar metabolites.

RESULTS

MPI expression was various in human esophageal cancer cells. KYSE70 cells was associated with the highest MPI expression whereas KYSE450 cells had the lowest MPI expression level. When administrated with 11.1 mM/L mannose, the same inhibitory effect was observed in both KYSE70 and KYSE450 cell lines. Moreover, the inhibitory effect was significant on KYSE450 cell lines with an increased mannose concentration. The application of 11.1 mM/L mannose could significantly enhance the radio-sensitivity of KYSE450 cell line; and tumor cell apoptosis rate was also increased. However, there was limited efficacy of mannose on the radio-sensitivity and apoptosis rate of KYSE70 cell line. Additionally, intracellular metabolites analyzation revealed that glycolysis could be disturbed by mannose when combined with radiation therapy in esophageal cancer cells.

CONCLUSION

In esophageal cancer cell lines with low MPI expression, the administration of mannose was associated with enhanced radio-sensitivity.

Circular RNA circ_0000592 elevates ANXA4 expression via sponging miR-1179 to facilitate tumor progression in gastric cancer

Increasing evidence indicated that dysregulated circular RNAs were implicated in the progression of multiple malignancies. However, the function of circ_0000592 in gastric cancer (GC) progression and its associated mechanism remain poorly understood. Quantitative real-time PCR and Western blot assay were performed to detect RNA and protein expression. Cell proliferation, migration and invasion were analyzed by 5-Ethynyl-2'-deoxyuridine staining assay, Transwell migration assay and Transwell invasion assay, respectively. The glucose/lactate assay kit was used to assess the rates of glucose consumption and lactate production. The interaction between microRNA-1179 (miR-1179) and circ_0000592 or Annexin A4 (ANXA4) was confirmed by dual-luciferase reporter assay and RNA pull-down assay. Xenograft tumor model was established to investigate the effect of circ_0000592 on tumor growth in vivo. Circ_0000592 expression was elevated in GC tissues and cells. Circ_0000592 knockdown hampered cell proliferation, migration, invasion and glycolysis of GC cells. MiR-1179 was a direct target of circ_0000592, and circ_0000592 silencing-mediated effects in GC cells were partly reversed by the knockdown of miR-1179. MiR-1179 interacted with the 3' untranslated region (3'UTR) of ANXA4. Circ_0000592 silencing reduced ANXA4 expression partly by upregulating miR-1179 in GC cells. ANXA4 overexpression partly overturned circ_0000592 knockdown-induced effects in GC cells. Circ_0000592 depletion markedly suppressed xenograft tumor growth in vivo. Circ_0000592 contributed to GC progression through regulating miR-1179/ANXA4 axis, which provided novel potential biomarkers and therapeutic targets for GC treatment.

Lactate-related metabolic reprogramming and immune regulation in colorectal cancer

Changes in cellular metabolism involving fuel sources are well-known mechanisms of cancer cell differentiation in the context of carcinogenesis. Metabolic reprogramming is regulated by oncogenic signaling and transcriptional networks and has been identified as an essential component of malignant transformation. Hypoxic and acidified tumor microenvironment contributes mainly to the production of glycolytic products known as lactate. Mounting evidence suggests that lactate in the tumor microenvironment of colorectal cancer(CRC) contributes to cancer therapeutic resistance and metastasis. The contents related to the regulatory effects of lactate on metabolism, immune response, and intercellular communication in the tumor microenvironment of CRC are also constantly updated. Here we summarize the latest studies about the pleiotropic effects of lactate in CRC and the clinical value of targeting lactate metabolism as treatment. Different effects of lactate on various immune cell types, microenvironment characteristics, and pathophysiological processes have also emerged. Potential specific therapeutic targeting of CRC lactate metabolism is also discussed. With increased knowledge, effective druggable targets might be identified, with the aim of improving treatment outcomes by reducing chemoresistance.

Lactate: The Mediator of Metabolism and Immunosuppression

The Warburg effect, one of the hallmarks of tumors, produces large amounts of lactate and generates an acidic tumor microenvironment via using glucose for glycolysis. As a metabolite, lactate not only serves as a substrate to provide energy for supporting cell growth and development but also acts as an important signal molecule to affect the biochemical functions of intracellular proteins and regulate the biological functions of different kinds of cells. Notably, histone lysine lactylation (Kla) is identified as a novel post-modification and carcinogenic signal, which provides the promising and potential therapeutic targets for tumors. Therefore, the metabolism and functional mechanism of lactate are becoming one of the hot fields in tumor research. Here, we review the production of lactate and its regulation on immunosuppressive cells, as well as the important role of Kla in hepatocellular carcinoma. Lactate and Kla supplement the knowledge gap in oncology and pave the way for exploring the mechanism of oncogenesis and therapeutic targets. Research is still needed in this field.

Importance of T, NK, CAR T and CAR NK Cell Metabolic Fitness for Effective Anti-Cancer Therapy: A Continuous Learning Process Allowing the Optimization of T, NK and CAR-Based Anti-Cancer Therapies

Simple Summary

Cancer treatments are evolving at a very rapid pace. Some of the most novel anti-cancer medicines under development rely on the modification of immune cells in order to transform them into potent tumor-killing cells. However, the tumor microenvironment (TME) is competing for nutrients with these harnessed immune cells and therefore paralyzes their metabolic effective and active anti-cancer activities. Here we describe strategies to overcome these hurdles imposed on immune cell activity, which lead to therapeutic approaches to enhance metabolic fitness of the patient’s immune system with the objective to improve their anti-cancer capacity.

Abstract

Chimeric antigen receptor (CAR) T and CAR NK cell therapies opened new avenues for cancer treatment. Although original successes of CAR T and CAR NK cells for the treatment of hematological malignancies were extraordinary, several obstacles have since been revealed, in particular their use for the treatment of solid cancers. The tumor microenvironment (TME) is competing for nutrients with T and NK cells and their CAR-expressing counterparts, paralyzing their metabolic effective and active states. Consequently, this can lead to alterations in their anti-tumoral capacity and persistence in vivo. High glucose uptake and the depletion of key amino acids by the TME can deprive T and NK cells of energy and building blocks, which turns them into a state of anergy, where they are unable to exert cytotoxic activity against cancer cells. This is especially true in the context of an immune-suppressive TME. In order to re-invigorate the T, NK, CAR T and CAR NK cell-mediated antitumor response, the field is now attempting to understand how metabolic pathways might change T and NK responses and functions, as well as those from their CAR-expressing partners. This revealed ways to metabolically rewire these cells by using metabolic enhancers or optimizing pre-infusion in vitro cultures of these cells. Importantly, next-generation CAR T and CAR NK products might include in the future the necessary metabolic requirements by improving their design, manufacturing process and other parameters. This will allow the overcoming of current limitations due to their interaction with the suppressive TME. In a clinical setting, this might improve their anti-cancer effector activity in synergy with immunotherapies. In this review, we discuss how the tumor cells and TME interfere with T and NK cell metabolic requirements. This may potentially lead to therapeutic approaches that enhance the metabolic fitness of CAR T and CAR NK cells, with the objective to improve their anti-cancer capacity.

Interleukin -1β Promotes Lung Adenocarcinoma Growth and Invasion Through Promoting Glycolysis via p38 Pathway

Background

There is a close relationship among inflammation, glycolysis, and tumors. The IL-1 family includes important inflammatory cytokines, among which IL-1β has been widely studied. In this study, we focused on the effect of IL-1β on glycolysis of lung adenocarcinoma (LUAD) cells in vivo and in vitro and explored its possible mechanisms.

Methods

A bioinformatic database and quantitative real-time PCR were used to analyze the expression of glycolysis-related enzyme genes and their correlations with IL1β in human LUAD samples. The human LUAD cell line A549 and Lewis lung carcinoma LLC cell line were stimulated with IL-1β. In vitro treatment effects, including glycolysis level, migration, and invasion were evaluated with a glucose assay kit, lactate assay kit, Western blotting, wound healing, and the transwell method. We established a mouse model of subcutaneous tumors using LLC cells pretreated with IL-1β and analyzed in vivo treatment effects through positron-emission tomography-computed tomography and staining. Virtual screening and molecular dynamic simulation were used to screen potential inhibitors of IL-1β.

Results

Our results showed that IL1β was positively correlated with the expression of glycolysis-related enzyme genes in LUAD. Glycolysis, migration, and invasion significantly increased in A549 and LLC stimulated with IL-1β. In vivo, IL-1β increased growth, mean standard uptake value, and pulmonary tumor metastasis, which were inhibited by the glycolysis inhibitor 2-deoxy-D-glucose and p38-pathway inhibitors. Small molecular compound ZINC14610053 was suggested being a potential inhibitor of IL-1β.

Conclusion

IL-1β promotes glycolysis of LUAD cells through p38 signaling, further enhancing tumor-cell migration and invasion. These results show that IL-1β links inflammation to glycolysis in LUAD, and targeting IL-1β and the glycolysis pathway may be a potential therapeutic strategy for lung cancer.

Targeting cancer metabolism in the era of precision oncology

One hundred years have passed since Warburg discovered alterations in cancer metabolism, more than 70 years since Sidney Farber introduced anti-folates that transformed the treatment of childhood leukaemia, and 20 years since metabolism was linked to oncogenes. However, progress in targeting cancer metabolism therapeutically in the past decade has been limited. Only a few metabolism-based drugs for cancer have been successfully developed, some of which are in - or en route to - clinical trials. Strategies for targeting the intrinsic metabolism of cancer cells often did not account for the metabolism of non-cancer stromal and immune cells, which have pivotal roles in tumour progression and maintenance. By considering immune cell metabolism and the clinical manifestations of inborn errors of metabolism, it may be possible to isolate undesirable off-tumour, on-target effects of metabolic drugs during their development. Hence, the conceptual framework for drug design must consider the metabolic vulnerabilities of non-cancer cells in the tumour immune microenvironment, as well as those of cancer cells. In this Review, we cover the recent developments, notable milestones and setbacks in targeting cancer metabolism, and discuss the way forward for the field.

Hsa_circ_0001806 promotes glycolysis and cell progression in hepatocellular carcinoma through miR-125b/HK2

OBJECTIVE

Hepatocellular carcinoma (HCC) is one of the most common malignant tumours and a leading cause of cancer death. Circular RNA (circRNA) has been demonstrated to play an important role in regulating tumour development. The current study aims to explore the specific role of hsa_circ_0001806 during HCC progression.

METHODS

The expression of hsa_circ_0001806 in HCC tissues and cells was measured through qRT-PCR. Cell proliferation, apoptosis and migration were measured using CCK-8 and Annexin V/PI staining kits, and Transwell assay. Bioinformatics prediction and dual-luciferase reporter assay were adopted to explore the mechanism underlying the cell function of hsa_circ_0001806 in HCC cells. In addition, glycolysis was assessed by measuring the glucose uptake, lactate production and ATP level using a glucose assay kit, fluorometric lactate assay kit and ATP detection assay kit.

RESULTS

Hsa_circ_0001806 was up-regulated in HCC tissues and cells and positively associated with the advanced TNM stage, metastasis and poor overall survival. The overexpression of hsa_circ_0001806 promoted HCC cell proliferation, migration and glycolysis and inhibited cell apoptosis, while the silence of hsa_circ_0001806 showed an opposite effect. Furthermore, hsa_circ_0001806 acted as a sponge of miR-125b to up-regulate hexokinase II (HK2) expression. In addition, the inhibition of miR-125b and HK2 overexpression partly reversed the inhibitory effect of hsa_circ_0001806 silencing on HCC cell proliferation, migration and glycolysis.

CONCLUSION

The inhibition of hsa_circ_0001806 suppressed HCC cell proliferation, migration and glycolysis through mediating miR-125b/HK2 axis.

Understanding the Role of Autophagy in Cancer Formation and Progression Is a Real Opportunity to Treat and Cure Human Cancers

Simple Summary

The modulation of autophagy represents a potential therapeutic strategy for cancer. More than one hundred clinical trials have been conducted or are ongoing to explore the efficacy of autophagy modulators to reduce the tumor growth and potentiate the anti-cancer effects of conventional therapy. Despite this, the effective role of autophagy during tumor initiation, growth, and metastasis remains not well understood. Depending on the cancer type and stage of cancer, autophagy may have tumor suppressor properties as well as help cancer cells to proliferate and evade cancer therapy. The current review aims to summarize the current knowledge about the autophagy implications in cancer and report the therapeutic opportunities based on the modulation of the autophagy process.

Abstract

The malignant transformation of a cell produces the accumulation of several cellular adaptions. These changes determine variations in biological processes that are necessary for a cancerous cell to survive during stressful conditions. Autophagy is the main nutrient recycling and metabolic adaptor mechanism in eukaryotic cells, represents a continuous source of energy and biomolecules, and is fundamental to preserve the correct cellular homeostasis during unfavorable conditions. In recent decades, several findings demonstrate a close relationship between autophagy, malignant transformation, and cancer progression. The evidence suggests that autophagy in the cancer context has a bipolar role (it may act as a tumor suppressor and as a mechanism of cell survival for established tumors) and demonstrates that the targeting of autophagy may represent novel therapeutic opportunities. Accordingly, the modulation of autophagy has important clinical benefits in patients affected by diverse cancer types. Currently, about 30 clinical trials are actively investigating the efficacy of autophagy modulators to enhance the efficacy of cytotoxic chemotherapy treatments. A deeper understanding of the molecular pathways regulating autophagy in the cancer context will provide new ways to target autophagy for improving the therapeutic benefits. Herein, we describe how autophagy participates during malignant transformation and cancer progression, and we report the ultimate efforts to translate this knowledge into specific therapeutic approaches to treat and cure human cancers.

Structure-based molecular networking for the target discovery of novel germicidin derivatives from the sponge-associated streptomyces sp. 18A01

Four new α-pyrone derivatives, named germicidins P-S (1-4) along with nine known analogues (5-13) were discovered from the sponge-associated Streptomyces sp. 18A01 guided by Global Natural Products Social (GNPS) molecular networking, the LC-DAD-MS profile, and hexokinase II (HK2) inhibitory activity. The structures of 1-13 were elucidated by analysis of their HRMS, optical rotation, and NMR spectroscopic data. The absolute configurations of germicidin P (1) and germicidin Q (2) were determined on the basis of comparisons of experimental and theoretically calculated ECD spectra. Bioactivities of the isolated compounds were assayed against human HK2. The bioassay results showed that compounds 1-4 and 11-13 exhibited significant inhibitory activities against HK2, with IC₅₀ values ranging from 5.1 to 11.0 μM. A molecular docking simulation demonstrated that these germicidins were docked in the inner active site tunnel of HK2. Interestingly, the amino residue Arg91 has a better binding affinity and efficacy than the amino residue Asn89 in the process of HK2 binding to the ligands, resulting in better hexokinase inhibitory activity. This result provided a valuable perspective for better understanding their HK2 inhibition activity.

PDGFRβ Modulates Aerobic Glycolysis in Osteosarcoma HOS Cells via the PI3K/AKT/mTOR/c-Myc Pathway

Osteosarcoma is a malignant tumor abundant in vascular tissue, and its rich blood supply may have a significant impact on its metabolic characteristics. PDGFRβ is a membrane receptor highly expressed in osteosarcoma cells and vascular wall cells, and its effect on osteosarcoma metabolism needs to be further studied. In this study, we discussed the effect and mechanism of PDGFRβ on the glucose metabolism of osteosarcomaHOS cells. First, GSEA, Pearson's correlation test, and PPI correlation analysis indicated the positive regulation of PDGFRβ on aerobic glycolysis in osteosarcoma. The results of qPCR and western blot further confirmed the prediction of bioinformatics. Glucose metabolism experiments proved that PDGF/PDGFRβ couldeffectively promote the aerobic glycolysis of osteosarcoma cells. In addition, the mitochondrial membrane potential experiment proved that the metabolic change triggered by PDGFRβ was not caused by mitochondrial damage. PI3K pathway inhibitor LY294002 or MEK pathway inhibitor U0126, or Warburg effect inhibitor DCA was used to carry out western blot and glucose metabolism experiments, and the results showed that PDGFBB/PDGFRβ mainly activated the PI3K/AKT/mTOR/ c-Myc pathway to promote aerobic glycolysis in osteosarcoma HOS cells. The newly elucidated role of PDGFRβ provides a novel metabolic therapeutic target for osteosarcoma.

A bioinformatics analysis of the contribution of m6A methylation to the occurrence of diabetes mellitus

N6-methyladenosine (m6A) methylation has been reported to play a role in type 2 diabetes (T2D). However, the key component of m6A methylation has not been well explored in T2D. This study investigates the biological role and the underlying mechanism of m6A methylation genes in T2D. The Gene Expression Omnibus (GEO) database combined with the m6A methylation and transcriptome data of T2D patients were used to identify m6A methylation differentially expressed genes (mMDEGs). Ingenuity pathway analysis (IPA) was used to predict T2D-related differentially expressed genes (DEGs). Gene ontology (GO) term enrichment and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to determine the biological functions of mMDEGs. Gene set enrichment analysis (GSEA) was performed to further confirm the functional enrichment of mMDEGs and determine candidate hub genes. The least absolute shrinkage and selection operator (LASSO) regression analysis was carried out to screen for the best predictors of T2D, and RT-PCR and Western blot were used to verify the expression of the predictors. A total of 194 overlapping mMDEGs were detected. GO, KEGG, and GSEA analysis showed that mMDEGs were enriched in T2D and insulin signaling pathways, where the insulin gene (INS), the type 2 membranal glycoprotein gene (MAFA), and hexokinase 2 (HK2) gene were found. The LASSO regression analysis of candidate hub genes showed that the INS gene could be invoked as a predictive hub gene for T2D. INS, MAFA,and HK2 genes participate in the T2D disease process, but INS can better predict the occurrence of T2D.

Quantitative proteomics analysis reveals novel insights into mechanisms of action of disulfiram (DSF)

PURPOSE

Disulfiram (DSF) has been proven safe and shows the promising antitumor effect in preclinical studies. However, the precise mechanism of DSF on tumor is rarely reported. This study aims to fully understand the mechanism of action of DSF with a systems perspective in anticancer effects.

EXPERIMENTAL DESIGN

SILAC-based quantitative proteomics strategy was used to systematically identify differential expression proteins (DEPs) after DSF treatment in HeLa cells. Bioinformatical analysis (PANTHER, DAVID, and STRING) were performed to characterize biological functions of DEPs. Functional studies were performed to explore underlying mechanisms of DSF in cancer cells.

RESULTS

In total, 201 proteins were dysregulated significantly after DSF exposure. Functional studies of hexokinase 2 (HK2), which catalyzed the first irreversible enzymatic step in glucose metabolism, revealed that various phenotypic effects observed after DSF treatment in cancer cells, at least partly, through the regulation of HK2 expression.

CONCLUSIONS AND CLINICAL RELEVANCE

By correlating the proteomics data with these functional studies, the current results provided novel insights into the mechanism underlying DSF function in cancer cells. Meanwhile, these provided theoretical basis for the new use of old drugs in clinical therapy.

The Warburg effect as a therapeutic target for bladder cancers and intratumoral heterogeneity in associated molecular targets

Bladder cancer is the 10th most common cancer worldwide. For muscle-invasive bladder cancer (MIBC), treatment includes radical cystectomy, radiotherapy, and chemotherapy; however, the outcome is generally poor. For non-muscle-invasive bladder cancer (NMIBC), tumor recurrence is common. There is an urgent need for more effective and less harmful therapeutic approaches. Here, bladder cancer cell metabolic reprogramming to rely on aerobic glycolysis (the Warburg effect) and expression of associated molecular therapeutic targets by bladder cancer cells of different stages and grades, and in freshly resected clinical tissue, is investigated. Importantly, analyses indicate that the Warburg effect is a feature of both NMIBCs and MIBCs. In two in vitro inducible epithelial-mesenchymal transition (EMT) bladder cancer models, EMT stimulation correlated with increased lactate production, the end product of aerobic glycolysis. Protein levels of lactate dehydrogenase A (LDH-A), which promotes pyruvate enzymatic reduction to lactate, were higher in most bladder cancer cell lines (compared with LDH-B, which catalyzes the reverse reaction), but the levels did not closely correlate with aerobic glycolysis rates. Although LDH-A is expressed in normal urothelial cells, LDH-A knockdown by RNAi selectively induced urothelial cancer cell apoptotic death, whereas normal cells were unaffected-identifying LDH-A as a cancer-selective therapeutic target for bladder cancers. LDH-A and other potential therapeutic targets (MCT4 and GLUT1) were expressed in patient clinical specimens; however, positive staining varied in different areas of sections and with distance from a blood vessel. This intratumoral heterogeneity has important therapeutic implications and indicates the possibility of tumor cell metabolic coupling.

Unraveling and targeting RAS-driven metabolic signaling for therapeutic gain

RAS mutations are among the most frequent oncogenic drivers observed in human cancers. With a lack of available treatment options, RAS-mutant cancers account for many of the deadliest cancers in the United States. Recent studies established that altered metabolic requirements are a hallmark of cancer, and many of these alterations are driven by aberrant RAS signaling. Specifically, RAS-driven cancers are characterized by upregulated glycolysis, the differential channeling of glycolytic intermediates, upregulated nutrient scavenging pathways such as autophagy and macropinocytosis, and altered glutamine utilization and mitochondrial function. This unique metabolic landscape promotes tumorigenesis, proliferation, survival in nutrient deficient environments and confers resistance to conventional cytotoxic and targeted therapies. Emerging work demonstrates how these dependencies can be therapeutically exploited in vitro and in vivo with many metabolic inhibitors currently in clinical trials. This review aims to outline the unique metabolic requirements induced by aberrant RAS signaling and how these altered dependencies present opportunities for therapeutic intervention.

Methylation-associated silencing of miR-9-1 promotes nasopharyngeal carcinoma progression and glycolysis via HK2

Characteristically, cancer cells metabolize glucose through aerobic glycolysis, known as the Warburg effect. Accumulating evidence suggest that during cancer formation, microRNAs (miRNAs) could regulate such metabolic reprogramming. In the present study, miR‐9‐1 was identified as significantly hypermethylated in nasopharyngeal carcinoma (NPC) cell lines and clinical tissues. Ectopic expression of miR‐9‐1 inhibited NPC cell growth and glycolytic metabolism, including reduced glycolysis, by reducing lactate production, glucose uptake, cellular glucose‐6‐phosphate levels, and ATP generation in vitro and tumor proliferation in vivo. HK2 (encoding hexokinase 2) was identified as a direct target of miR‐9‐1 using luciferase reporter assays and Western blotting. In NPC cells, hypermethylation regulates miR‐9‐1 expression and inhibits HK2 translation by directly targeting its 3' untranslated region. MiR‐9‐1 overexpression markedly reduced HK2 protein levels. Restoration of HK2 expression attenuated the inhibitory effect of miR‐9‐1 on NPC cell proliferation and glycolysis. Fluorescence in situ hybridization results indicated that miR‐9‐1 expression was an independent prognostic factor in NPC. Our findings revealed the role of the miR‐9‐1/HK2 axis in the metabolic reprogramming of NPC, providing a potential therapeutic strategy for NPC.

Targeting hexokinase 2 increases the sensitivity of oxaliplatin by Twist1 in colorectal cancer

Colorectal cancer (CRC) is the third most malignant tumour worldwide, with high mortality and recurrence. Chemoresistance is one of the main factors leading to metastasis and poor prognosis in advanced CRC patients. By analysing the Gene Expression Omnibus data set, we found higher hexokinase 2 (HK2) expression levels in patients with metastatic CRC than in those with primary CRC. Moreover, we observed higher enrichment in oxaliplatin resistance‐related gene sets in metastatic CRC than in primary CRC. However, the underlying relationship has not yet been elucidated. In our study, HK2 expression was significantly elevated in CRC patients. Gene set enrichment analysis (GSEA) revealed multi‐drug resistance and epithelial‐mesenchymal transition (EMT) pathways related to high HK2 expression. Our results showed that knockdown of HK2 significantly inhibited vimentin and Twist1 expression and promoted TJP1 and E‐cadherin expression in CRC cells. Additionally, transcriptional and enzymatic inhibition of HK2 by 3‐bromopyruvate (3‐bp) impaired oxaliplatin resistance in vitro and in vivo. Mechanistically, HK2 interacts with and stabilized Twist1 by preventing its ubiquitin‐mediated degradation, which is related to oxaliplatin resistance, in CRC cells. Overexpression of Twist1 reduced the apoptosis rate by HK2 knockdown in CRC cells. Collectively, we discovered that HK2 is a crucial regulator that mediates oxaliplatin resistance through Twist1. These findings identify HK2 and Twist1 as promising drug targets for CRC chemoresistance.

Novel Mitochondria-targeted Drugs for Cancer Therapy

The search for mitochondria-targeted drugs has dramatically risen over the last decade. Mitochondria are essential organelles serving not only as a powerhouse of the cell but also as a key player in cell proliferation and cell death. Their central role in the energetic metabolism, calcium homeostasis and apoptosis makes them an intriguing field of interest for cancer pharmacology. In cancer cells, many mitochondrial signaling and metabolic pathways are altered. These changes contribute to cancer development and progression. Due to changes in mitochondrial metabolism and changes in membrane potential, cancer cells are more susceptible to mitochondria-targeted therapy. The loss of functional mitochondria leads to the arrest of cancer progression and/or a cancer cell death. Identification of mitochondrial changes specific for tumor growth and progression, rational development of new mitochondria-targeted drugs and research on delivery agents led to the advance of this promising area. This review will highlight the current findings in mitochondrial biology, which are important for cancer initiation, progression and resistance, and discuss approaches of cancer pharmacology with a special focus on the anti-cancer drugs referred to as 'mitocans'.

Metabolic reprograming confers tamoxifen resistance in breast cancer

Breast cancer is the most common cancer among females and the leading cause of cancer-related deaths. Approximately 70 % of breast cancers are estrogen receptor (ER) positive. An ER antagonist such as tamoxifen is used as adjuvant therapy in ER-positive patients. The major problem with endocrine therapy is the emergence of acquired resistance in approximately 40 % of patients receiving tamoxifen. Metabolic alteration is one of the hallmarks of cancer cells. Rapidly proliferating cancer cells require increased nutritional support to fuel various functions such as proliferation, cell migration, and metastasis. Recent studies have established that the metabolic state of cancer cells influences their susceptibility to chemotherapeutic drugs and that cancer cells reprogram their metabolism to develop into resistant phenotypes. In this review, we discuss the major findings on metabolic pathway alterations in tamoxifen-resistant (TAMR) breast cancer and the molecular mechanisms known to regulate the expression and function of metabolic enzymes and the respective metabolite levels upon tamoxifen treatment. It is anticipated that this in-depth analysis of specific metabolic pathways in TAMR cancer might be exploited therapeutically.

Potential therapeutics using tumor-secreted lactate in nonsmall cell lung cancer

Targeted-therapy failure in treating nonsmall cell lung cancer (NSCLC) frequently occurs because of the emergence of drug resistance and genetic mutations. The same mutations also result in aerobic glycolysis, which further antagonizes outcomes by localized increases in lactate, an immune suppressor. Recent evidence indicates that enzymatic lowering of lactate can promote an oncolytic immune microenvironment within the tumour. Here, we review factors relating to lactate expression in NSCLC and the utility of lactate oxidase (LOX) for governing therapeutic delivery, its role in lactate oxidation and turnover, and relationships between lactate depletion and immune cell populations. The lactate-rich characteristic of NSCLC provides an exploitable property to potentially improve NSCLC outcomes and design new therapeutic strategies to integrate with conventional therapies.

Analysis of the Effects of Hexokinase 2 Detachment From Mitochondria-Associated Membranes with the Highly Selective Peptide HK2pep

The crucial role of hexokinase 2 (HK2) in the metabolic rewiring of tumors is now well established, which makes it a suitable target for the design of novel therapies. However, hexokinase activity is central to glucose utilization in all tissues; thus, enzymatic inhibition of HK2 can induce severe adverse effects. In an effort to find a selective anti-neoplastic strategy, we exploited an alternative approach based on HK2 detachment from its location on the outer mitochondrial membrane. We designed a HK2-targeting peptide named HK2pep, corresponding to the N-terminal hydrophobic domain of HK2 and armed with a metalloprotease cleavage sequence and a polycation stretch shielded by a polyanion sequence. In the tumor microenvironment, metalloproteases unleash polycations to allow selective plasma membrane permeation in neoplastic cells. HK2pep delivery induces the detachment of HK2 from mitochondria-associated membranes (MAMs) and mitochondrial Ca2+ overload caused by the opening of inositol-3-phosphate receptors on the endoplasmic reticulum (ER) and Ca2+ entry through the plasma membrane leading to Ca2+-mediated calpain activation and mitochondrial depolarization. As a result, HK2pep rapidly elicits death of diverse tumor cell types and dramatically reduces in vivo tumor mass. HK2pep does not affect hexokinase enzymatic activity, avoiding any noxious effect on non-transformed cells. Here, we make available a detailed protocol for the use of HK2pep and to investigate its biological effects, providing a comprehensive panel of assays to quantitate both HK2 enzymatic activity and changes in mitochondrial functions, Ca2+ flux, and cell viability elicited by HK2pep treatment of tumor cells. Graphical abstract: Flowchart for the analysis of the effects of HK2 detachment from MAMs.

TBC1D9: An Important Modulator of Tumorigenesis in Breast Cancer

Triple-negative breast cancer (TNBC) is a major concern among the different subtypes of breast cancer (BC) due to the lack of effective treatment. In a previous study by our group aimed at understanding the difference between TNBC and non-TNBC tumors, we identified the gene TBC1 domain family member 9 (TBC1D9), the expression of which was lower in TNBC as compared to non-TNBC tumors. In the present study, analysis of TBC1D9 expression in TNBC (n = 58) and non-TNBC (n = 25) patient tumor samples validated that TBC1D9 expression can differentiate TNBC (low) from non-TNBC (high) samples and that expression of TBC1D9 was inversely correlated with grade and proliferative index. Moreover, we found that downregulation of the TBC1D9 gene decreases the proliferation marginally in non-TNBC and was associated with increased migratory and tumorigenic potential in both TNBC and luminal BC cell lines. This increase was mediated by the upregulation of ARL8A, ARL8B, PLK1, HIF1α, STAT3, and SPP1 expression in TBC1D9 knockdown cells. Our results suggest that TBC1D9 expression might limit tumor aggressiveness and that it has a differential expression in TNBC vs. non-TNBC tumors.

MicroRNA-216b targets HK2 to potentiate autophagy and apoptosis of breast cancer cells via the mTOR signaling pathway

Patients suffering from breast cancer (BC) still have a poor response to treatments, even though early detection and improved therapy have contributed to a reduced mortality. Recent studies have been inspired on the association between microRNAs (miRs) and therapies of BC. The current study set out to investigate the role of miR-216b in BC, and further analyze the underlining mechanism. Firstly, hexokinase 2 (HK2) and miR-216b were characterized in BC tissues and cells by RT-qPCR and Western blot assay. In addition, the interaction between HK2 and miR-216b was analyzed using dual luciferase reporter assay. BC cells were further transfected with a series of miR-126b mimic or inhibitor, or siRNA targeting HK2, so as to analyze the regulatory mechanism of miR-216b, HK2 and mammalian target of rapamycin (mTOR) signaling pathway, and to further explore their regulation in BC cellular behaviors. The results demonstrated that HK2 was highly expressed and miR-216b was poorly expressed in BC cells and tissues. HK2 was also verified as a target of miR-216b with online databases and dual luciferase reporter assay. Functionally, miR-216b was found to be closely associated with BC progression via inactivating mTOR signaling pathway by targeting HK2. Moreover, cell viability, migration and invasion were reduced as a result of miR-216b upregulation or HK2 silencing, while autophagy, cell cycle arrest and apoptosis were induced. Taken together, our findings indicated that miR-216 down-regulates HK2 to inactivate the mTOR signaling pathway, thus inhibiting the progression of BC. Hence, this study highlighted a novel target for BC treatment.

Silencing of circHIPK3 Sensitizes Paclitaxel-Resistant Breast Cancer Cells to Chemotherapy by Regulating HK2 Through Targeting miR-1286

Background

Resistance development to paclitaxel (PTX) has become a major obstacle in the successful treatment of breast cancer (BC). Circular RNAs (circRNAs) have been identified as essential regulators in PTX resistance of BC. Here, we explored the precise roles of circRNA homeodomain interacting protein kinase 3 (circHIPK3, circ_0000284) in PTX resistance of BC.

Methods

The expression levels of circHIPK3, microRNA (miR)-1286, and hexokinase 2 (HK2) were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Ribonuclease R (RNase R) assay was used to confirm the stability of circHIPK3. Cellular localization of circHIPK3 was assessed by subcellular localization assay. The half maximal inhibitory concentration (IC₅₀) value for PTX was measured by Cell Counting Kit-8 (CCK-8) assay. Cell colony formation, cell cycle distribution, and apoptosis were gauged by colony formation assay and flow cytometry, respectively. Animal studies were performed to evaluate the role of circHIPK3 in vivo. The direct relationship between miR-1286 and circHIPK3 or HK2 was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

Results

Our results showed that circHIPK3 was up-regulated in PTX-resistant BC tissues and cells compared with the sensitive counterparts. The silencing of circHIPK3 promoted PTX sensitivity of PTX-resistant BC cells in vitro and in vivo. CircHIPK3 directly targeted miR-1286, and miR-1286 acted as a downstream mediator of circHIPK3 function in vitro. HK2 was a direct target of miR-1286, and circHIPK3 modulated HK2 expression through miR-1286. The increased expression of miR-1286 sensitized PTX-resistant BC cells to PTX in vitro by down-regulating HK2.

Conclusion

Our findings demonstrated that the silencing of circHIPK3 sensitized PTX-resistant BC cells to PTX therapy at least in part via the regulation of the miR-1286/HK2 axis.

Nuclear HKII-P-p53 (Ser15) Interaction is a Prognostic Biomarker for Chemoresponsiveness and Glycolytic Regulation in Epithelial Ovarian Cancer

Simple Summary

Hexokinase II (HKII) is a key glycolysis enzyme associated with tumorigenesis, but its molecular mechanism and pathophysiological role in chemoresistant ovarian cancer remain elusive. In this study, we delineate the novel mechanism showing that activated phosphorylated-p53 (P-p53 Ser15) is required for the regulation of HKII intracellular trafficking and metabolic regulation in chemosensitive ovarian cancer, but not in chemoresistant ovarian cancer harboring p53 mutation. We have observed that increased nuclear HKII-P-p53 (Ser15) interaction is likely associated with chemosensitivity and better survival outcomes in epithelial ovarian cell lines, human primary epithelial ovarian cancer cells, and tumor sections. Nuclear HKII-P-p53 (Ser15) interaction may function as a promising prognostic biomarker, enabling prediction of patients with poor prognosis for deciding better clinical strategies.

Abstract

In epithelial ovarian cancer (EOC), carboplatin/cisplatin-induced chemoresistance is a major hurdle to successful treatment. Aerobic glycolysis is a common characteristic of cancer. However, the role of glycolytic metabolism in chemoresistance and its impact on clinical outcomes in EOC are not clear. Here, we show a functional interaction between the key glycolytic enzyme hexokinase II (HKII) and activated P-p53 (Ser15) in the regulation of bioenergetics and chemosensitivity. Using translational approaches with proximity ligation assessment in cancer cells and human EOC tumor sections, we showed that nuclear HKII-P-p53 (Ser15) interaction is increased after chemotherapy, and functions as a determinant of chemoresponsiveness as a prognostic biomarker. We also demonstrated that p53 is required for the intracellular nuclear HKII trafficking in the control of glycolysis in EOC, associated with chemosensitivity. Mechanistically, cisplatin-induced P-p53 (Ser15) recruits HKII and apoptosis-inducing factor (AIF) in chemosensitive EOC cells, enabling their translocation from the mitochondria to the nucleus, eliciting AIF-induced apoptosis. Conversely, in p53-defective chemoresistant EOC cells, HKII and AIF are strongly bound in the mitochondria and, therefore, apoptosis is suppressed. Collectively, our findings implicate nuclear HKII-P-p53(Ser15) interaction in chemosensitivity and could provide an effective clinical strategy as a promising biomarker during platinum-based therapy.

Extracellular Vesicle Transmission of Chemoresistance to Ovarian Cancer Cells Is Associated with Hypoxia-Induced Expression of Glycolytic Pathway Proteins, and Prediction of Epithelial Ovarian Cancer Disease Recurrence

Simple Summary

Ovarian cancer is one of the most lethal cancers affecting women worldwide. Its high mortality rate is often attributed to the non-specific nature of early symptoms of the disease. Developing a better understanding of the disease progression and identifying clinically useful biomarkers that aid in clinical management are requisite to reducing the mortality rate of ovarian cancer. Reduced oxygen tension (i.e., hypoxia) is not only a characteristic of solid tumors but may also enhance the metastatic capacity of tumors by inducing the release of tumor growth promoting factors. Recently, it has been proposed that small tumor-derived extracellular vesicles (sEVs) facilitate cancer progression. In this study, we established that sEVs produced under low oxygen tension induce a metabolic switch in ovarian cancer cells associated with changes in glycolytic pathway proteins that promote resistance to carboplatin. Significantly, we identified a suite of sEV-associated glycolysis pathway proteins that are present in patients with ovarian cancer that can predict disease recurrence with over 90% accuracy.

Abstract

Hypoxia is a key regulator of cancer progression and chemoresistance. Ambiguity remains about how cancer cells adapt to hypoxic microenvironments and transfer oncogenic factors to surrounding cells. In this study, we determined the effects of hypoxia on the bioactivity of sEVs in a panel of ovarian cancer (OvCar) cell lines. The data obtained demonstrate a varying degree of platinum resistance induced in OvCar cells when exposed to low oxygen tension (1% oxygen). Using quantitative mass spectrometry (Sequential Window Acquisition of All Theoretical Fragment Ion Mass Spectra, SWATH) and targeted multiple reaction monitoring (MRM), we identified a suite of proteins associated with glycolysis that change under hypoxic conditions in cells and sEVs. Interestingly, we identified a differential response to hypoxia in the OvCar cell lines and their secreted sEVs, highlighting the cells’ heterogeneity. Proteins are involved in metabolic reprogramming such as glycolysis, including putative hexokinase (HK), UDP-glucuronosyltransferase 1–6 (UD16), and 6-phosphogluconolactonase (6 PGL), and their presence correlates with the induction of platinum resistance. Furthermore, when normoxic cells were exposed to sEVs from hypoxic cells, platinum-resistance increased significantly (p < 0.05). Altered chemoresistance was associated with changes in glycolysis and fatty acid synthesis. Finally, sEVs isolated from a clinical cohort (n = 31) were also found to be enriched in glycolysis-pathway proteins, especially in patients with recurrent disease. These data support the hypothesis that hypoxia induces changes in sEVs composition and bioactivity that confers carboplatin resistance on target cells. Furthermore, we propose that the expression of sEV-associated glycolysis-pathway proteins is predictive of ovarian cancer recurrence and is of clinical utility in disease management.

NR5A2 Is One of 12 Transcription Factors Predicting Prognosis in HNSCC and Regulates Cancer Cell Proliferation in a p53-Dependent Manner

Head and neck squamous cell carcinoma (HNSCC) rank seventh among the most common type of malignant tumor worldwide. Various evidences suggest that transcriptional factors (TFs) play a critical role in modulating cancer progression. However, the prognostic value of TFs in HNSCC remains unclear. Here, we identified a risk model based on a 12-TF signature to predict recurrence-free survival (RFS) in patients with HNSCC. We further analyzed the ability of the 12-TF to predict the disease-free survival time and overall survival time in HNSCC, and found that only NR5A2 down-regulation was strongly associated with shortened overall survival and disease-free survival time in HNSCC. Moreover, we systemically studied the role of NR5A2 in HNSCC and found that NR5A2 regulated HNSCC cell growth in a TP53 status-dependent manner. In p53 proficient cells, NR5A2 knockdown increased the expression of TP53 and activated the p53 pathway to enhance cancer cells proliferation. In contrast, NR5A2 silencing suppressed the growth of HNSCC cells with p53 loss/deletion by inhibiting the glycolysis process. Therefore, our results suggested that NR5A2 may serve as a promising therapeutic target in HNSCC harboring loss-of-function TP53 mutations.