Expression of hexokinase II and Glut-1 in untreated human breast cancer

Redox and metabolic reprogramming in breast cancer and cancer-associated adipose tissue

Redox and metabolic processes are tightly coupled in both physiological and pathological conditions. In cancer, their integration occurs at multiple levels and is characterized by synchronized reprogramming both in the tumor tissue and its specific but heterogeneous microenvironment. In breast cancer, the principal microenvironment is the cancer-associated adipose tissue (CAAT). Understanding how the redox-metabolic reprogramming becomes coordinated in human breast cancer is imperative both for cancer prevention and for the establishment of new therapeutic approaches. This review aims to provide an overview of the current knowledge of the redox profiles and regulation of intermediary metabolism in breast cancer while considering the tumor and CAAT of breast cancer as a unique Warburg's pseudo-organ. As cancer is now recognized as a systemic metabolic disease, we have paid particular attention to the cell-specific redox-metabolic reprogramming and the roles of estrogen receptors and circadian rhythms, as well as their crosstalk in the development, growth, progression, and prognosis of breast cancer.

MicroRNA-98 as a novel diagnostic marker and therapeutic target in cancer patients

The progress of cancer treatment methods in the last decade has significantly reduced mortality rate among these patients. Nevertheless, cancer is still recognized as one of the main causes of human deaths. One of the main reasons for the high death rate in cancer patients is the late diagnosis in the advanced tumor stages. Therefore, it is necessary to investigate the molecular biology of tumor progressions in order to introduce early diagnostic markers. MicroRNAs (miRNAs) have an important role in regulating cellular processes associated with tumor progression. Due to the high stability of miRNAs in body fluids, they are widely used as non-invasive markers in the early tumor diagnosis. Since, deregulation of miR-98 has been reported in a wide range of cancers, we investigated the molecular mechanisms of miR-98 during tumor progression. It has been reported that miR-98 mainly inhibits the tumor growth by the modulation of transcription factors and signaling pathways. Therefore, miR-98 can be introduced as a tumor marker and therapeutic target among cancer patients.

Association of 18F- fluorodeoxyglucose uptake with the expression of metabolism-related molecules in papillary thyroid cancer

OBJECTIVES

18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) is a diagnostic imaging method that is based on the Warburg effect, which is the increased uptake of glucose through aerobic glycolysis in cancer cells. The diagnostic value of 18F-FDG-PET/CT for thyroid cancer is controversial. However, uptake of 18F-FDG and the corresponding maximum standardized uptake value (SUVmax) is expected to reflect the metabolic status of cancer cells. In the present study, we sought to determine the relationship between 18F-FDG uptake and tumor metabolism- associated factors.

METHODS

This was a single-center retrospective study. In the present study, SUVmax was compared with the expression of hexokinase 2 (HK2), glucose transporter 1 (GLUT1), vascular endothelial growth factor (VEGF), and glutaminase 1 (GLS1) in 41 patients with thyroid cancer.

RESULTS

GLS1 expression was found to be moderately correlated with SUVmax (p < 0.001, r = 0.51), whereas HK2 and VEGF expression were weakly correlated (p = 0.011, r = 0.28, p = 0.008, r = 0.29, respectively) and GLUT1 did not correlate with SUVmax (p = 0.62, r = 0.06).

CONCLUSION

Our findings suggest 18F-FDG PET/CT reflects GLS1 expression in thyroid cancer and could be used to select suitable candidates for GLS1 inhibitor treatment.

DAB2IP inhibits glucose uptake by modulating HIF-1α ubiquitination under hypoxia in breast cancer

Metabolic reprogramming has become increasingly important in tumor biology research. The glucose metabolic pathway is a major energy source and is often dysregulated in breast cancer. DAB2IP is widely reported to be a tumor suppressor that acts as a scaffold protein to suppress tumor malignancy in breast cancer. Interestingly, DAB2IP has also been found to be a potential regulator of glucose uptake; however, the exact mechanism remains unclear. In this study, we found that DAB2IP inhibited glucose uptake under hypoxia conditions in breast cancer cells by suppressing HIF-1α signals. Mechanically, DAB2IP interacted with the E3 ubiquitin ligase STUB1 via its PER domain, thus triggering STUB1 mediated HIF-1α ubiquitylation and degradation, and inhibit glucose metabolism and tumor progression. Deleting the PER domain abrogated the DAB2IP-related inhibitory effects on glucose uptake, intracellular ATP production, and lactic acid production in breast cancer cells. These findings elucidate the biological roles of DAB2IP in cancer-related glucose metabolism as well as a novel mechanism by which STUB1-driven HIF-1α ubiquitylated degradation is regulated in breast cancer.

Knockdown of Glycolysis-Related LINC01070 Inhibits the Progression of Breast Cancer

Accumulative evidence confirms that glycolysis and long non-coding RNAs (lncRNAs) are closely associated with tumor development. The aim of this study was to construct a novel prognostic model based on glycolysis-related lncRNAs (GRLs) in breast cancer patients. By performing Pearson correlation analysis and Lasso regression analysis on differentially expressed genes and lncRNAs associated with glycolysis in the Cancer Genome Atlas (TCGA) and Gene Set Enrichment Analysis (GSEA) datasets, we identified nine GRLs and constructed associated prognostic risk signature. Kaplan-Meier survival analysis and univariate and multivariate Cox analysis showed that patients in the low-risk group had a better prognosis. The receiver operator characteristics (ROC) curves showed that the area under the curve (AUC) of the prognostic risk signature predicting patients' overall survival at 1-, 3- and 5- years was 0.78, 0.71, and 0.71, respectively. Moreover, the validation curves also showed that the signature had better diagnostic efficacy and clinical predictive power. Furthermore, clone formation assay, EdU assay, and Transwell assay showed that knockdown of LINC01070 inhibited breast cancer progression. We developed a prognostic risk-associated GRLs signature that can accurately predict the breast cancer patient's prognostic status, and LINC01070 can be used as a potential biomarker for the prognosis of breast cancer patients.

Targeting metabolism of breast cancer and its implications in T cell immunotherapy

Breast cancer is a prominent health issue amongst women around the world. Immunotherapies including tumor targeted antibodies, adoptive T cell therapy, vaccines, and immune checkpoint blockers have rejuvenated the clinical management of breast cancer, but the prognosis of patients remains dismal. Metabolic reprogramming and immune escape are two important mechanisms supporting the progression of breast cancer. The deprivation uptake of nutrients (such as glucose, amino acid, and lipid) by breast cancer cells has a significant impact on tumor growth and microenvironment remodeling. In recent years, in-depth researches on the mechanism of metabolic reprogramming and immune escape have been extensively conducted, and targeting metabolic reprogramming has been proposed as a new therapeutic strategy for breast cancer. This article reviews the abnormal metabolism of breast cancer cells and its impact on the anti-tumor activity of T cells, and further explores the possibility of targeting metabolism as a therapeutic strategy for breast cancer.

Patlak Reconstruction Using Dynamic 18 F-FDG PET Imaging for Evaluation of Malignant Liver Tumors : A Comparison of HCC, ICC, and Metastatic Liver Tumors

PURPOSE OF THE REPORT

The aim of this study was to explore the different patterns of dynamic whole-body (D-WB) FDG PET/CT parameters among liver malignancy types as potential diagnostic clues and investigate the association between static and dynamic PET/CT parameters for each tumor histology.

PATIENTS AND METHODS

Seventy-one patients with intrahepatic cholangiocarcinoma (ICC), metastatic liver tumor (MLT), or hepatocellular carcinoma (HCC) who underwent D-WB and static dual-time-point FDG PET/CT were enrolled. We obtained Pearson correlation coefficients between the metabolic rate of FDG (MR FDG ; mg/min/ 100ml) or distribution volume of free FDG (DV FDG , %) and static PET/CT parameters. We compared MR FDG and DV FDG values by tumor type and performed receiver operating characteristic analyses for MR FDG and static images.

RESULTS

A total of 12 ICC, 116 MLT, and 36 HCC lesions were analyzed. MR FDG and DV FDG showed excellent correlation with early (SUV e ) and delayed SUV max (SUV d ) ( r = 0.71~0.97), but DV FDG in the HCC lesions did not ( r = 0.62 and 0.69 for SUV e and SUV d , respectively) ( P < 0.001 for all). HCC lesions showed significantly lower MR FDG (2.43 ± 1.98) and DV FDG (139.95 ± 62.58) than ICC (5.02 ± 3.56, 207.06 ± 97.13) and MLT lesions (4.51 ± 2.47, 180.13 ± 75.58) ( P < 0.01 for all). The optimal MR FDG could differentiate HCC from ICC and MLT with areas under the curve of 0.84 and 0.80, respectively. Metastatic liver tumor lesions showed the widest distribution of MR FDG and DV FDG values but with no significant difference among most primary sites.

CONCLUSIONS

MR FDG was strongly correlated with SUV max in the 3 malignancies and showed utility for differentiating HCC from ICC and MLT. Each tumor type has a different glucose metabolism, and D-WB FDG PET/CT imaging has the potential to visualize those differences.

SOX4-SMARCA4 complex promotes glycolysis-dependent TNBC cell growth through transcriptional regulation of Hexokinase 2

Tumor cells rely on increased glycolytic capacity to promote cell growth and progression. While glycolysis is known to be upregulated in the majority of triple negative (TNBC) or basal-like subtype breast cancers, the mechanism remains unclear. Here, we used integrative genomic analyses to identify a subset of basal-like tumors characterized by increased expression of the oncogenic transcription factor SOX4 and its co-factor the SWI/SNF ATPase SMARCA4. These tumors are defined by unique gene expression programs that correspond with increased tumor proliferation and activation of key metabolic pathways, including glycolysis. Mechanistically, we demonstrate that the SOX4-SMARCA4 complex mediates glycolysis through direct transcriptional regulation of Hexokinase 2 (HK2) and that aberrant HK2 expression and altered glycolytic capacity are required to mediate SOX4-SMARCA4-dependent cell growth. Collectively, we have defined the SOX4-SMARCA4-HK2 signaling axis in basal-like breast tumors and established that this axis promotes metabolic reprogramming which is required to maintain tumor cell growth.

Metabolic Alterations in Canine Mammary Tumors

Canine mammary tumors (CMTs) are among the most common diseases in female dogs and share similarities with human breast cancer, which makes these animals a model for comparative oncology studies. In these tumors, metabolic reprogramming is known as a hallmark of carcinogenesis whereby cells undergo adjustments to meet the high bioenergetic and biosynthetic demands of rapidly proliferating cells. However, such alterations are also vulnerabilities that may serve as a therapeutic strategy, which has mostly been tested in human clinical trials but is poorly explored in CMTs. In this dedicated review, we compiled the metabolic changes described for CMTs, emphasizing the metabolism of carbohydrates, amino acids, lipids, and mitochondrial functions. We observed key factors associated with the presence and aggressiveness of CMTs, such as an increase in glucose uptake followed by enhanced anaerobic glycolysis via the upregulation of glycolytic enzymes, changes in glutamine catabolism due to the overexpression of glutaminases, increased fatty acid oxidation, and distinct effects depending on lipid saturation, in addition to mitochondrial DNA, which is a hotspot for mutations. Therefore, more attention should be paid to this topic given that targeting metabolic fragilities could improve the outcome of CMTs.

Glycolytic enzyme HK2 promotes PD-L1 expression and breast cancer cell immune evasion

Immune therapies targeting the PD-1/PD-L1 pathway have been employed in the treatment of breast cancer, which requires aerobic glycolysis to sustain breast cancer cells growth. However, whether PD-L1 expression is regulated by glycolysis in breast cancer cells remains to be further elucidated. Here, we demonstrate that glycolytic enzyme hexokinase 2 (HK2) plays a crucial role in upregulating PD-L1 expression. Under high glucose conditions, HK2 acts as a protein kinase and phosphorylates IκBα at T291 in breast cancer cells, leading to the rapid degradation of IκBα and activation of NF-κB, which enters the nucleus and promotes PD-L1 expression. Immunohistochemistry staining of human breast cancer specimens and bioinformatics analyses reveals a positive correlation between HK2 and PD-L1 expression levels, which are inversely correlated with immune cell infiltration and survival time of breast cancer patients. These findings uncover the intrinsic and instrumental connection between aerobic glycolysis and PD-L1 expression-mediated tumor cell immune evasion and underscore the potential to target the protein kinase activity of HK2 for breast cancer treatment.

Apoptotic proteins with non-apoptotic activity: expression and function in cancer

Apoptosis is a process of programmed cell death in which a cell commits suicide while maintaining the integrity and architecture of the tissue as a whole. Apoptosis involves activation of one of two major pathways: the extrinsic pathway, where extracellular pro-apoptotic signals, transduced through plasma membrane death receptors, activate a caspase cascade leading to apoptosis. The second, the intrinsic apoptotic pathway, where damaged DNA, oxidative stress, or chemicals, induce the release of pro-apoptotic proteins from the mitochondria, leading to the activation of caspase-dependent and independent apoptosis. However, it has recently become apparent that proteins involved in apoptosis also exhibit non-cell death-related physiological functions that are related to the cell cycle, differentiation, metabolism, inflammation or immunity. Such non-conventional activities were predominantly reported in non-cancer cells although, recently, such a dual function for pro-apoptotic proteins has also been reported in cancers where they are overexpressed. Interestingly, some apoptotic proteins translocate to the nucleus in order to perform a non-apoptotic function. In this review, we summarize the unconventional roles of the apoptotic proteins from a functional perspective, while focusing on two mitochondrial proteins: VDAC1 and SMAC/Diablo. Despite having pro-apoptotic functions, these proteins are overexpressed in cancers and this apparent paradox and the associated pathophysiological implications will be discussed. We will also present possible mechanisms underlying the switch from apoptotic to non-apoptotic activities although a deeper investigation into the process awaits further study.

Energy metabolism pathways in breast cancer progression: The reprogramming, crosstalk, and potential therapeutic targets

Breast cancer (BC) is a malignant tumor that seriously endangers health in women. BC, like other cancers, is accompanied by metabolic reprogramming. Among energy metabolism-related pathways, BC exhibits enhanced glycolysis, tricarboxylic acid (TCA) cycle, pentose phosphate pathway (PPP), glutamate metabolism, and fatty acid metabolism activities. These pathways facilitate the proliferation, growth and migration of BC cells. The progression of BC is closely related to the alterations in the activity or expression level of several metabolic enzymes, which are regulated by the intrinsic factors such as the key signaling and transcription factors. The metabolic reprogramming in the progression of BC is attributed to the aberrant expression of the signaling and transcription factors associated with the energy metabolism pathways. Understanding the metabolic mechanisms underlying the development of BC will provide a druggable potential for BC treatment and drug discovery.

Monitoring and modelling the dynamics of the cellular glycolysis pathway: A review and future perspectives

BACKGROUND

The dynamics of the cellular glycolysis pathway underpin cellular function and dysfunction, and therefore ultimately health, disease, diagnostic and therapeutic strategies. Evolving our understanding of this fundamental process and its dynamics remains critical.

SCOPE OF REVIEW

This paper reviews the medical relevance of glycolytic pathway in depth and explores the current state of the art for monitoring and modelling the dynamics of the process. The future perspectives of label free, vibrational microspectroscopic techniques to overcome the limitations of the current approaches are considered.

MAJOR CONCLUSIONS

Vibrational microspectroscopic techniques can potentially operate in the niche area of limitations of other omics technologies for non-destructive, real-time, in vivo label-free monitoring of glycolysis dynamics at a cellular and subcellular level.

Long non-coding RNAs affecting cell metabolism in cancer

Metabolic reprogramming is commonly recognized as one important hallmark of cancers. Cancer cells present significant alteration of glucose metabolism, oxidative phosphorylation, and lipid metabolism. Recent findings demonstrated that long non-coding RNAs control cancer development and progression by modulating cell metabolism. Here, we give an overview of breast cancer metabolic reprogramming and the role of long non-coding RNAs in driving cancer-specific metabolic alteration.

Hexokinase 2: The preferential target of trehalose-6-phosphate over hexokinase 1

Cancer-related metabolic features are in part maintained by hexokinase 2 upregulation, which leads to high levels of glucose-6-phosphate (G6P) and is needed to provide energy and biomass to support rapid proliferation. Using a humanized model of the yeast Saccharomyces cerevisiae, we explored how human hexokinase 2 (HK2) behaves under different nutritional conditions. At high glucose levels, yeast presents aerobic glycolysis through a regulatory mechanism known as catabolic repression, which exerts a metabolic adaptation like the Warburg effect. At high glucose concentrations, HK2 did not translocate into the nucleus and was not able to shift the metabolism toward a highly glycolytic state, in contrast to the effect of yeast hexokinase 2 (Hxk2), which is a crucial protein for the control of aerobic glycolysis in S. cerevisiae. During the stationary phase, when glucose is exhausted, Hxk2 is shuttled out of the nucleus, ceasing catabolic repression. Cells harvested at this condition display low glucose consumption rates. However, glucose-starved cells expressing HK2 had an increased capacity to consume glucose. In those cells, HK2 localized to mitochondria, becoming insensitive to G6P inhibition. We also found that the sugar trehalose-6-phosphate (T6P) is a human HK2 inhibitor, like yeast Hxk2, but was not able to inhibit human HK1, the isoform that is ubiquitously expressed in almost all mammalian tissues. In contrast to G6P, T6P inhibited HK2 even when HK2 was associated with mitochondria. The binding of HK2 to mitochondria is crucial for cancer survival and proliferation. T6P was able to reduce the cell viability of tumor cells, although its toxicity was not impressive. This was expected as cell absorption of phosphorylated sugars is low, which might be counteracted using nanotechnology. Altogether, these data suggest that T6P may offer a new paradigm for cancer treatment based on specific inhibition of HK2.

Glucose Metabolism and Glucose Transporters in Breast Cancer

Breast cancer is the most common malignancy in women worldwide and is associated with high mortality rates despite the continuously advancing treatment strategies. Glucose is essential for cancer cell metabolism owing to the Warburg effect. During the process of glucose metabolism, various glycolytic metabolites, such as serine and glycine metabolites, are produced and other metabolic pathways, such as the pentose phosphate pathway (PPP), are associated with the process. Glucose is transported into the cell by glucose transporters, such as GLUT. Breast cancer shows high expressions of glucose metabolism-related enzymes and GLUT, which are also related to breast cancer prognosis. Triple negative breast cancer (TNBC), which is a high-grade breast cancer, is especially dependent on glucose metabolism. Breast cancer also harbors various stromal cells such as cancer-associated fibroblasts and immune cells as tumor microenvironment, and there exists a metabolic interaction between these stromal cells and breast cancer cells as explained by the reverse Warburg effect. Breast cancer is heterogeneous, and, consequently, its metabolic status is also diverse, which is especially affected by the molecular subtype, progression stage, and metastatic site. In this review, we will focus on glucose metabolism and glucose transporters in breast cancer, and we will additionally discuss their potential applications as cancer imaging tracers and treatment targets.

Metabolic changes in triple negative breast cancer-focus on aerobic glycolysis

Among breast cancer subtypes, the triple negative breast cancer (TNBC) has the worst prognosis. In absence of any permitted targeted therapy, standard chemotherapy is the mainstay for TNBC treatment. Hence, there is a crucial need to identify potential druggable targets in TNBCs for its effective treatment. In recent times, metabolic reprogramming has emerged as cancer cells hallmark, wherein cancer cells display discrete metabolic phenotypes to fuel cell progression and metastasis. Altered glycolysis is one such phenotype, in which even in oxygen abundance majority of cancer cells harvest considerable amount of energy through elevated glycolytic-flux. In the present review, we attempt to summarize the role of key glycolytic enzymes i.e. HK, Hexokinase; PFK, Phosphofructokinase; PKM2, Pyruvate kinase isozyme type 2; and LDH, Lactate dehydrogenase in TNBCs, and possible therapeutic options presently available.

Regulation of Glycolysis in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) glycolysis is an important factor for the advancement of the disease and metastasis. Upregulation of glycolysis leads to decreased sensitivity to chemotherapy and radiation. HNSCC cells maintain constitutive glycolytic flux generating metabolic intermediates for the synthesis of amino acids, nucleotides, and fats for cell survival and disease progression. There are several pathways such as PI3K/Akt, EGFR, and JAK-STAT that contribute a major role in metabolic alteration in HNSCC. Recent studies have demonstrated that cancer-associated fibroblasts abundant in the HNSCC tumor microenvironment play a major role in HNSCC metabolic alteration via hepatocyte growth factor (HGF)/c-Met cross signaling. Despite therapeutic advancement, HNSCC lacks broad range of therapeutic interventions for the treatment of the disease. Thus, understanding the different key players involved in glucose metabolism and targeting them would lead to the development of novel drugs for the treatment of HNSCC.

Metabolism and immunity in breast cancer

Breast cancer is one of the most common malignancies that seriously threaten women's health. In the process of the malignant transformation of breast cancer, metabolic reprogramming and immune evasion represent the two main fascinating characteristics of cancer and facilitate cancer cell proliferation. Breast cancer cells generate energy through increased glucose metabolism. Lipid metabolism contributes to biological signal pathways and forms cell membranes except energy generation. Amino acids act as basic protein units and metabolic regulators in supporting cell growth. For tumor-associated immunity, poor immunogenicity and heightened immunosuppression cause breast cancer cells to evade the host's immune system. For the past few years, the complex mechanisms of metabolic reprogramming and immune evasion are deeply investigated, and the genes involved in these processes are used as clinical therapeutic targets for breast cancer. Here, we review the recent findings related to abnormal metabolism and immune characteristics, regulatory mechanisms, their links, and relevant therapeutic strategies.

Hexokinase inhibition using D-Mannoheptulose enhances oncolytic newcastle disease virus-mediated killing of breast cancer cells

Background

Most cancer cells exhibit increased glycolysis and use this metabolic pathway cell growth and proliferation. Targeting cancer cells' metabolism is a promising strategy in inhibiting cancer cell progression. We used D-Mannoheptulose, a specific hexokinase inhibitor, to inhibit glycolysis to enhance the Newcastle disease virus anti-tumor effect.

Methods

Human breast cancer cells were treated by NDV and/or hexokinase inhibitor. The study included cell viability, apoptosis, and study levels of hexokinase enzyme, pyruvate, ATP, and acidity. The combination index was measured to determine the synergism of NDV and hexokinase inhibitor.

Results

The results showed synergistic cytotoxicity against breast cancer cells by combination therapy but no cytotoxic effect against normal cells. The effect was accompanied by apoptotic cell death and hexokinase downregulation and inhibition to glycolysis products, pyruvate, ATP, and acidity.

Conclusions

The combination treatment showed safe significant tumor cell proliferation inhibition compared to monotherapies suggesting a novel strategy for anti-breast cancer therapy through glycolysis inhibition by hexokinase downregulation.

Cryptanshinone Inhibits the Glycolysis and Inhibits Cell Migration Through PKM2/β-Catenin Axis in Breast Cancer

Background

Breast cancer is one of the most prevalent gynecologic malignancies worldwide. Despite the high sensitivity in response to chemotherapy, drug resistance occurred frequently in clinical treatment. Cryptotanshinone (CTS) is a herbal medicine and has been identified as an anti-inflammatory and anti-oxidative drug.

Methods

In vitro assays, including the cell proliferation assay, colony formation assay, Western blot analysis, transwell migration/invasion assays, and cell scratch assay were used to explore the biological activities and working mechanism of CTS. Breast cancer cells were also transfected with PKM2 expressing vectors to define the molecular mechanisms involved in CTS-mediated anti-tumor activity.

Results

We found that CTS shows anti-proliferative effects and decreases the clonogenic ability of breast cancer cells. We also found that CTS inhibited the migration and invasion activity of MCF-7 and MDA-MB-231 cells by different analyzed methods. CTS also downregulated the levels of glycolysis-related proteins, such as PKM2, LDHA, and HK2. In addition, overexpression of PKM2 recovered CTS-mediated suppression of cell proliferation, colony formation, and cell mobility of breast cancer cells. We also found PKM2 was significantly overexpressed in tumor tissues and invasive ductal breast carcinoma compared to normal tissues and patients with high PKM2 expression had worse overall survival and metastasis-free survival outcomes.

Conclusion

CTS inhibited the proliferation, migration, and invasion of breast cancer cells. The involved mechanism may refer to the downregulation of the PKM2/β-catenin axis.

Simvastatin induces breast cancer cell death through oxidative stress up-regulating miR-140-5p

Statins, a class of hyperlipidemic drugs, are widely used cholesterol lowering drugs that selectively inhibit 3-hydroxy-3-methylglutaryl CoA reductase, which is the rate-limiting enzyme in cholesterol biosynthesis, leading to decreasing of cholesterol biosynthesis. Statins exert anti-tumoral effects on various cancer, including breast cancer. However, the molecular mechanisms for the actions were not fully elucidated. The purpose of this study was to elucidate the effects of statins on proliferation and apoptosis in the ER-negative breast cancer cell line MDA-MB-231. Our results showed that simvastatin increased the expression of miR-140-5p in a dose dependent manner via activating transcription factor NRF1, reduced cell proliferation and induced apoptosis, and we also found that SLC2A1 was a new target of miR-140-5p. In conclusion, data in this study shed light on the potential anti-tumoral effects of simvastatin in breast cancer and presents a highly promising therapeutic option, using drug and miRNA for combined treating cancers.

Energy Metabolism in Cancer: The Roles of STAT3 and STAT5 in the Regulation of Metabolism-Related Genes

A central characteristic of many types of cancer is altered energy metabolism processes such as enhanced glucose uptake and glycolysis and decreased oxidative metabolism. The regulation of energy metabolism is an elaborate process involving regulatory proteins such as HIF (pro-metastatic protein), which reduces oxidative metabolism, and some other proteins such as tumour suppressors that promote oxidative phosphorylation. In recent years, it has been demonstrated that signal transducer and activator of transcription (STAT) proteins play a pivotal role in metabolism regulation. STAT3 and STAT5 are essential regulators of cytokine- or growth factor-induced cell survival and proliferation, as well as the crosstalk between STAT signalling and oxidative metabolism. Several reports suggest that the constitutive activation of STAT proteins promotes glycolysis through the transcriptional activation of hypoxia-inducible factors and therefore, the alteration of mitochondrial activity. It seems that STAT proteins function as an integrative centre for different growth and survival signals for energy and respiratory metabolism. This review summarises the functions of STAT3 and STAT5 in the regulation of some metabolism-related genes and the importance of oxygen in the tumour microenvironment to regulate cell metabolism, particularly in the metabolic pathways that are involved in energy production in cancer cells.

Can Increased Metabolic Status be a Grading Tool for Oral Squamous Cell Carcinoma? A Glucose Transporter 1 Immunoexpression Study

Background:

Glucose transporter-1 (GLUT-1) is a GLUT protein whose expression is upregulated in malignant cells where enhanced uptake of glucose is observed.

Aim:

The aim of this study is to evaluate the expression of GLUT-1 protein in oral squamous cell carcinoma (OSCC) tissue sections using immunohistochemistry and to describe the relationship between increased metabolic status and the grades of OSCC.

Materials and Methods:

This is cross-sectional study with 76 formalin-fixed paraffin-embedded tissue blocks of OSCC, obtained from the archives of the department. All the cases were scored using Bryne's grading system by three oral pathologists independently. The tissue sections were then stained using immunohistochemistry with anti-GLUT-1 rabbit monoclonal antibody.

Results:

Staining intensity and localization of positively stained slides were evaluated. Overall, a significant correlation between Bryne's histopathological grading system for OSCC and GLUT-1 immunohistochemical expression was observed. Thus, high GLUT-1 expressions are observed with increasing grades of OSCC.

Conclusion:

This study shows that a significant positive correlation exists between GLUT-1 immunoexpression and histological grading of OSCC. Thus, GLUT-1 expression can be used as a diagnostic adjunct and prognostic marker for OSCC patients.

Metabolic crosstalk in the breast cancer microenvironment

During tumorigenesis, breast tumour cells undergo metabolic reprogramming, which generally includes enhanced glycolysis, tricarboxylic acid cycle activity, glutaminolysis and fatty acid biosynthesis. However, the extension and functional importance of these metabolic alterations may diverge not only according to breast cancer subtypes, but also depending on the interaction of cancer cells with the complex surrounding microenvironment. This microenvironment comprises a variety of non-cancerous cells, such as immune cells (e.g. macrophages, lymphocytes, natural killer cells), fibroblasts, adipocytes and endothelial cells, together with extracellular matrix components and soluble factors, which influence cancer progression and are predictive of clinical outcome. The continuous interaction between cancer and stromal cells results in metabolic competition and symbiosis, with oncogenic-driven metabolic reprogramming of cancer cells shaping the metabolism of neighbouring cells and vice versa. This review addresses current knowledge on this metabolic crosstalk within the breast tumour microenvironment (TME). Improved understanding of how metabolism in the TME modulates cancer development and evasion of tumour-suppressive mechanisms may provide clues for novel anticancer therapeutics directed to metabolic targets.

Radioisotope imaging for discriminating benign from malignant cytologically indeterminate thyroid nodules

The risk of malignancy in thyroid nodules with indeterminate cytological classification (Bethesda III-IV) ranges from 10% to 40%, and early delineation is essential as delays in diagnosis can be associated with increased mortality. Several radioisotope imaging techniques are available for discriminating benign from malignant cytologically indeterminate thyroid nodules, and for supporting clinical decision-making. These techniques include iodine-123, technetium-99m-pertechnetate, technetium-99m-methoxy-isobutyl-isonitrile (technetium-99m-MIBI), and fluorine-18-fluorodeoxyglucose (fluorine-18-FDG). This review discusses the currently available radioisotope imaging techniques for evaluation of thyroid nodules, including the mechanism of radiotracer uptake and the indications for their use.

Emerging roles of aerobic glycolysis in breast cancer

Altered aerobic glycolysis is a well-recognized characteristic of cancer cell energy metabolism, known as the Warburg effect. Even in the presence of abundant oxygen, a majority of tumor cells produce substantial amounts of energy through a high glycolytic metabolism, and breast cancer (BC) is no exception. Breast cancer continues to be the second leading cause of cancer-associated mortality in women worldwide. However, the precise role of aerobic glycolysis in the development of BC remains elusive. Therefore, the present review attempts to address the implication of key enzymes of the aerobic glycolytic pathway including hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK), glucose transporters (GLUTs), together with related signaling pathways including protein kinase B(PI3K/AKT), mammalian target of rapamycin (mTOR) and adenosine monophosphate-activated protein kinase (AMPK) and transcription factors (c-myc, p53 and HIF-1) in the research of BC. Thus, the review of aerobic glycolysis in BC may evoke novel ideas for the BC treatment.

miR‑185 regulates the growth of osteosarcoma cells via targeting Hexokinase 2

MicroRNAs (miRNAs) have been proposed as potential prognostic and diagnostic biomarkers in numerous types of cancer, including osteosarcoma (OS), which is the most common bone malignancy. The present study revealed that the expression of miR‑185 was downregulated in OS tissues and cells. Overexpression of miR‑185 significantly suppressed the proliferation and migration of OS cells. To further investigate the functional roles of miR‑185 in OS, the downstream targets of miR‑185 were predicted using the microRNA.org database. The results revealed that in cancer cells, hexokinase 2 (HK2), the rate‑limiting enzyme of glycolysis, was a potential target of miR‑185. Molecular analysis indicated that miR‑185 binds to the 3'‑untranslated region of HK2 mRNA. Overexpressed miR‑185 downregulated the mRNA and protein levels of HK2 in OS cells. In addition, an inverse correlation between the expression of miR‑185 and HK2 was reported in OS. Consistent with the downregulation of HK2 induced by miR‑185, overexpression of HK2 in OS cells significantly attenuated the inhibitory effects of miR‑185 on glucose consumption and lactate production, while depletion of miR‑185 promoted the glycolysis of OS cells. Additionally, restoration of HK2 abolished the inhibitory effects of miR‑185 on the proliferation of OS cells. In summary, these results revealed that miR‑185 suppressed the glucose metabolism of OS cells; thus, miR‑185 may be considered as a promising therapeutic target for the treatment of OS.

The CIMP-high phenotype is associated with energy metabolism alterations in colon adenocarcinoma

BACKGROUND

CpG island methylator phenotype (CIMP) is found in 15-20% of malignant colorectal tumors and is characterized by strong CpG hypermethylation over the genome. The molecular mechanisms of this phenomenon are not still fully understood. The development of CIMP is followed by global gene expression alterations and metabolic changes. In particular, CIMP-low colon adenocarcinoma (COAD), predominantly corresponded to consensus molecular subtype 3 (CMS3, "Metabolic") subgroup according to COAD molecular classification, is associated with elevated expression of genes participating in metabolic pathways.

METHODS

We performed bioinformatics analysis of RNA-Seq data from The Cancer Genome Atlas (TCGA) project for CIMP-high and non-CIMP COAD samples with DESeq2, clusterProfiler, and topGO R packages. Obtained results were validated on a set of fourteen COAD samples with matched morphologically normal tissues using quantitative PCR (qPCR).

RESULTS

Upregulation of multiple genes involved in glycolysis and related processes (ENO2, PFKP, HK3, PKM, ENO1, HK2, PGAM1, GAPDH, ALDOA, GPI, TPI1, and HK1) was revealed in CIMP-high tumors compared to non-CIMP ones. Most remarkably, the expression of the PKLR gene, encoding for pyruvate kinase participating in gluconeogenesis, was decreased approximately 20-fold. Up to 8-fold decrease in the expression of OGDHL gene involved in tricarboxylic acid (TCA) cycle was observed in CIMP-high tumors. Using qPCR, we confirmed the increase (4-fold) in the ENO2 expression and decrease (2-fold) in the OGDHL mRNA level on a set of COAD samples.

CONCLUSIONS

We demonstrated the association between CIMP-high status and the energy metabolism changes at the transcriptomic level in colorectal adenocarcinoma against the background of immune pathway activation. Differential methylation of at least nine CpG sites in OGDHL promoter region as well as decreased OGDHL mRNA level can potentially serve as an additional biomarker of the CIMP-high status in COAD.

Targeting Mitochondrial Ion Channels to Fight Cancer

In recent years, several experimental evidences have underlined a new role of ion channels in cancer development and progression. In particular, mitochondrial ion channels are arising as new oncological targets, since it has been proved that most of them show an altered expression during tumor development and the pharmacological targeting of some of them have been demonstrated to be able to modulate cancer growth and progression, both in vitro as well as in vivo in pre-clinical mouse models. In this scenario, pharmacology of mitochondrial ion channels would be in the near future a new frontier for the treatment of tumors. In this review, we discuss the new advances in the field, by focusing our attention on the improvements in new drug developments to target mitochondrial ion channels.

Cancer-associated fibroblasts enhance tumor 18F-FDG uptake and contribute to the intratumor heterogeneity of PET-CT

Purpose: Elevated glucose uptake is a hallmark of cancer. Fluorodeoxyglucose (FDG) uptake was believed to indicate the aggressiveness of tumors and the standardized uptake value (SUV) is a well-known measurement for FDG uptake in positron emission tomography-computed tomography (PET/CT). However, the SUV is variable due to the heterogeneity of tumors. Methods: 126 patients with colorectal cancer underwent ¹⁸F-FDG PET/CT scanning before surgery between Jan 2011 and April 2016. Cancer-associated fibroblast (CAF) densities were calculated with the inForm Advanced image analysis software and were comparatively analyzed between patients with high and low maximum SUV (SUVmax-high and SUVmax-low). Glucose uptake was evaluated in induced and isolated CAFs and CAF-cocultured colon cancer HCT116 cells. Moreover, micro-PET/CT was performed on xenografted tumors and autoradiography was performed in the AOM/DSS induced colon cancer model. Results: CAFs were glycolytic, evidenced by glucose uptake and upregulated HK2 expression. Compared to non-activated fibroblasts (NAFs), CAFs were more dependent on glucose and sensitive to a glycolysis inhibitor. CAFs increased the SUVmax in xenograft tumors and spontaneous colon cancers. Moreover, multivariate analysis revealed that the SUVmax was only associated with tumor size among conventional parameters in colon cancer patients (126 cases, p = 0.009). Besides tumor size, the CAF density was the critical factor associated with SUVmax and outcome, which was 2.27 ± 0.74 and 1.68 ± 0.45 in the SUVmax-high and the SUVmax-low groups, respectively (p = 0.014). Conclusion: CAFs promote tumor progression and increase SUVmax of ¹⁸F-FDG, suggesting CAFs lead to the intratumor heterogeneity of the SUV and the SUVmax is a prognostic marker for cancer patients.

Voltage-Dependent Anion Channel 1 As an Emerging Drug Target for Novel Anti-Cancer Therapeutics

Cancer cells share several properties, high proliferation potential, reprogramed metabolism, and resistance to apoptotic cues. Acquiring these hallmarks involves changes in key oncogenes and non-oncogenes essential for cancer cell survival and prosperity, and is accompanied by the increased energy requirements of proliferating cells. Mitochondria occupy a central position in cell life and death with mitochondrial bioenergetics, biosynthesis, and signaling are critical for tumorigenesis. Voltage-dependent anion channel 1 (VDAC1) is situated in the outer mitochondrial membrane (OMM) and serving as a mitochondrial gatekeeper. VDAC1 allowing the transfer of metabolites, fatty acid ions, Ca²⁺, reactive oxygen species, and cholesterol across the OMM and is a key player in mitochondrial-mediate apoptosis. Moreover, VDAC1 serves as a hub protein, interacting with diverse sets of proteins from the cytosol, endoplasmic reticulum, and mitochondria that together regulate metabolic and signaling pathways. The observation that VDAC1 is over-expressed in many cancers suggests that the protein may play a pivotal role in cancer cell survival. However, VDAC1 is also important in mitochondria-mediated apoptosis, mediating release of apoptotic proteins and interacting with anti-apoptotic proteins, such as B-cell lymphoma 2 (Bcl-2), Bcl-xL, and hexokinase (HK), which are also highly expressed in many cancers. Strategically located in a “bottleneck” position, controlling metabolic homeostasis and apoptosis, VDAC1 thus represents an emerging target for anti-cancer drugs. This review presents an overview on the multi-functional mitochondrial protein VDAC1 performing several functions and interacting with distinct sets of partners to regulate both cell life and death, and highlights the importance of the protein for cancer cell survival. We address recent results related to the mechanisms of VDAC1-mediated apoptosis and the potential of associated proteins to modulate of VDAC1 activity, with the aim of developing VDAC1-based approaches. The first strategy involves modification of cell metabolism using VDAC1-specific small interfering RNA leading to inhibition of cancer cell and tumor growth and reversed oncogenic properties. The second strategy involves activation of cancer cell death using VDAC1-based peptides that prevent cell death induction by anti-apoptotic proteins. Finally, we discuss the potential therapeutic benefits of treatments and drugs leading to enhanced VDAC1 expression or targeting VDAC1 to induce apoptosis.

Strategies to Target Glucose Metabolism in Tumor Microenvironment on Cancer by Flavonoids

The imbalance between glucose metabolism and cancer cell growth in tumor microenvironment (TME), which are closely related with the occurrence and progression of cancer. Accumulating evidence has demonstrated that flavonoids exert many biological properties, including antioxidant and anticarcinogenic activities. Recently, the roles and applications of flavonoids, particularly in relation to glucose metabolism in cancers, have been highlighted. Thus, the identification of flavonoids targeting alternative glucose metabolism pathways in TME may represent an attractive approach to the more effective therapeutic strategies for cancer. In this review, we will focus on the roles of flavonoids in regulating glucose metabolism and cancer cell growth in TME, such as proliferation advantage, cell mobility, and chemoresistance to cancer, as well as modifiers of thermal sensitivity. Not only have such large-scale endeavors been useful in providing fundamental insights into natural and synthesized flavonoids that can prevent and treat cancer, but also have led to the discovery of potential targets for cancer therapy.

MicroRNA-98 Suppress Warburg Effect by Targeting HK2 in Colon Cancer Cells

BACKGROUND

Warburg effect is a hallmark of cancer cells. Accumulating evidence suggests that microRNAs (miRs) could regulate such metabolic reprograming. Aberrant expression of miR-98 has been observed in many types of cancers. However, its functions and significance in colon cancer remain largely elusive.

AIMS

To investigate miR-98 expression and the biological functions in colon cancer progression.

METHODS

miR-98 expression levels were determined by quantitative RT-PCR in 215 cases of colon cancer samples. miR-98 mimic or inhibitor was used to test the biological functions in SW480 and HCT116 cells, followed by cell proliferation assay, lactate production, glucose uptake, and cellular ATP levels assay and extracellular acidification rates measurement. Western blot and luciferase assay were used to identify the target of miR-98.

RESULTS

miR-98 was significantly down-regulated in colon cancer tissues compared to adjacent colon tissues and acted as a suppressor for Warburg effect in cancer cells. miR-98 inhibited glycolysis by directly targeting hexokinase 2, or HK2, illustrating a novel pathway to mediate Warburg effect of cancer cells. In vitro experiments further indicated that HK2 was involved in miR-98-mediated suppression of glucose uptake, lactate production, and cell proliferation. In addition, we detected HK2 expression in colon cancer tissues and found that the expressions of miR-98 and HK2 were negatively correlated.

CONCLUSION

miR-98 acts as tumor suppressor gene and inhibits Warburg effect in colon cancer cells, which provided potential targets for clinical treatments.

The glucose transporter GLUT1 is required for ErbB2-induced mammary tumorigenesis

BACKGROUND

Altered tumor cell metabolism is an emerging hallmark of cancer; however, the precise role for glucose in tumor initiation is not known. GLUT1 (SLC2A1) is expressed in breast cancer cells and is likely responsible for avid glucose uptake observed in established tumors. We have shown that GLUT1 was necessary for xenograft tumor formation from primary mammary cells transformed with the polyomavirus middle-T antigen but that it was not necessary for growth after tumors had formed in vivo, suggesting a differential requirement for glucose depending on the stage of tumorigenesis.

METHODS

To determine whether GLUT1 is required early during mammary tumorigenesis, we crossed MMTV-NIC mice, which express activated HER2/NEU/ERBB2 and Cre recombinase, to Slc2a1 ^Flox/Flox (GLUT1^Flox/Flox) mice to generate NIC-GLUT1^+/+, NIC-GLUT1^Flox/+, and NIC-GLUT1^Flox/Flox mice. In addition, we evaluated effects of glucose restriction or GLUT1 inhibition on transformation in MCF10A-ERBB2 breast epithelial cells in three-dimensional culture. Finally, we utilized global gene expression profiling data of primary human breast tumors to determine the relationship between SLC2A1 and stage of tumorigenesis.

RESULTS

All of the NIC-GLUT1^+/+ mice developed tumors in less than 200 days. In contrast, only 1 NIC-GLUT1^Flox/Flox mouse and 1 NIC-GLUT1^Flox/+ mouse developed mammary tumors, even after 18 months. Mammary gland development was not disrupted in NIC mice lacking GLUT1; however, epithelial content of mature glands was reduced compared to NIC-GLUT1^Flox/+ mice. In MCF10A-ERBB2 cells, glucose restriction or GLUT1 inhibition blocked transformation induced by activated ERBB2 through reduced cell proliferation. In human breast cancers, SLC2A1 was higher in ductal carcinoma in situ compared to the normal breast, but lower in invasive versus in situ lesions, suggesting the requirement for GLUT1 decreases as tumors progress.

CONCLUSIONS

This study demonstrates a strict requirement for GLUT1 in the early stages of mammary tumorigenesis in vitro and in vivo. While metabolic adaptation has emerged as a hallmark of cancer, our data indicate that early tumor cells rely heavily on glucose and highlight the potential for glucose restriction as a breast cancer preventive strategy.

Identification of Keratin 19-Positive Cancer Stem Cells Associating Human Hepatocellular Carcinoma Using 18F-Fluorodeoxyglucose Positron Emission Tomography

Purpose: The current lack of tools for easy assessment of cancer stem cells (CSC) prevents the development of therapeutic strategies for hepatocellular carcinoma (HCC). We previously reported that keratin 19 (K19) is a novel HCC-CSC marker and that PET with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is an effective method for predicting postoperative outcome in hepatocellular carcinoma. Herein, we examined whether K19⁺ HCC-CSCs can be tracked using ¹⁸F-FDG-PET.Experimental Design: K19 and glucose transporter-1 (GLUT1) expression was evaluated by IHC in 98 hepatocellular carcinoma patients who underwent ¹⁸F-FDG-PET scans before primary tumor resection. Standardized uptake values (SUV) for primary tumors and tumor-to-nontumor SUV ratios (TNR) were calculated using FDG accumulation levels, and values were compared among K19⁺/K19^- patients. Using hepatocellular carcinoma cell lines encoding with a K19 promoter-driven enhanced GFP, ¹⁸F-FDG uptake and GLUT1 expression were examined in FACS-isolated K19⁺/K19^- cells.Results: In hepatocellular carcinoma patients, K19 expression was significantly correlated with GLUT1 expression and FDG accumulation. ROC analyses revealed that among preoperative clinical factors, TNR was the most sensitive indicator of K19 expression in hepatocellular carcinoma tumors. In hepatocellular carcinoma cells, FACS-isolated K19⁺ cells displayed significantly higher ¹⁸F-FDG uptake than K19^- cells. Moreover, gain/loss-of-function experiments confirmed that K19 regulates ¹⁸F-FDG uptake through TGFβ/Smad signaling, including Sp1 and its downstream target GLUT1.Conclusions:¹⁸F-FDG-PET can be used to predict K19 expression in hepatocellular carcinoma and should thereby aid in the development of novel therapeutic strategies targeting K19⁺ HCC-CSCs. Clin Cancer Res; 23(6); 1450-60. ©2016 AACR.

Exploring Tumor Biology with Fluorodeoxyglucose-Positron Emission Tomography Imaging in Breast Carcinoma

This article reviews the promising application of fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging in exploring tumor biology of breast carcinoma based upon the authors' experience and also reviews current literature on this topic. The interest in this novel aspect of breast PET imaging has gained momentum in recent years as more is understood about the molecular subtypes and heterogeneous behavior of breast cancer. With the development of newer targeted therapies, oncologists are realizing the need for a means of accurate prediction and assessment of treatment response early in the course of therapy. Hence the studies on FDG-PET imaging in exploring the tumor biology of breast carcinoma have focused on: tumor histologic subtypes, hormonal receptor expression, disease burden at diagnosis, tumor proliferation index, and other molecular parameters. The correlation of various PET tracer parameters (eg, 15O-water PET-derived blood flow measurements and 18F-FDG-PET derived glucose metabolism rate parameters) is also of considerable interest. To summarize, the utility of FDG-PET/CT imaging on this aspect of breast carcinoma imaging holds considerable promise in disease characterization, and it can be foreseen that it will soon aid in guiding and adapting newer therapeutic regimens.

Involvement of ion channels and transporters in carcinoma angiogenesis and metastasis

Angiogenesis is a finely tuned process, which is the result of the equilibrium between pro- and antiangiogenic factors. In solid tumor angiogenesis, the balance is highly in favor of the production of new, but poorly functional blood vessels, initially intended to provide growing tumors with nutrients and oxygen. Among the numerous proteins involved in tumor development, several types of ion channels are overexpressed in tumor cells, as well as in stromal and endothelial cells. Ion channels thus actively participate in the different hallmarks of cancer, especially in tumor angiogenesis and metastasis. Indeed, from their strategic localization in the plasma membrane, ion channels are key operators of cell signaling, as they sense and respond to environmental changes. This review aims to decipher how ion channels of different families are intricately involved in the fundamental angiogenesis and metastasis hallmarks, which lead from a nascent tumor to systemic dissemination. An overview of the possible use of ion channels as therapeutic targets will also be given, showing that ion channel inhibitors or specific antibodies may provide effective tools, in the near future, in the treatment of carcinomas.

Clinicopathologic Features and Molecular Characteristics of Glucose Metabolism Contributing to ¹⁸F-fluorodeoxyglucose Uptake in Gastrointestinal Stromal Tumors

Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) is useful in the preoperative diagnosis of gastrointestinal stromal tumors (GISTs); however, the molecular characteristics of glucose metabolism of GIST are unknown. We evaluated 18F-FDG uptake on preoperative PET/CT of 40 patients and analyzed the expression of glycolytic enzymes in resected GIST tissues by qRT-PCR, western blotting, and immunohistochemistry. Results of receiver operating characteristic curve analysis showed that the maximum standardized uptake value (SUVmax) cut-off value of 4.99 had a sensitivity of 89.5%, specificity was 76.2%, and accuracy of 82.5% for identifying tumors with a high risk of malignancy. We found that 18F-FDG uptake correlated positively with tumor size, risk grade, and expression levels of glucose transporter 1 (GLUT1), hexokinase 1 (HK1), and lactate dehydrogenase A (LDHA). Elevated HK and LDH activity was found in high-risk tumors. Among the isoforms of GLUT and HK, GLUT1 and HK1 expression increased with higher tumor risk grade. In addition, overexpression of glycolytic enzymes M2 isoform of pyruvate kinase (PKM2) and LDHA was observed in GISTs, especially in high-risk tumors. These results suggest that upregulation of GLUT1, HK1, PKM2, and LDHA may play an important role in GIST tumorigenesis and may be useful in the preoperative prediction of malignant potential.

Deregulation of energetic metabolism in the clear cell renal cell carcinoma: A multiple pathway analysis based on microarray profiling

Clear cell renal cell carcinoma (ccRCC) is the most frequent type of kidney cancer. In order to better understand the biology of ccRCC, we accomplished the gene profiling of fresh tissue specimens from 11 patients with the renal tumors (9 ccRCCs, 1 oncocytoma and 1 renal B-lymphoma), in which the tumor-related data were compared to the paired healthy kidney tissues from the same patients. All ccRCCs exhibited a considerably elevated transcription of the gene coding for carbonic anhydrase IX (CAIX). Moreover, the ccRCC tumors consistently displayed increased expression of genes encoding the glycolytic pathway enzymes, e.g. hexokinase II (HK2) and lactate dehydrogenase A (LDHA) and a decreased expression of genes for the mitochondrial electron transport chain components, indicating an overall reprogramming of the energetic metabolism in this tumor type. This appears to be accompanied by altered expression of the genes of the pH regulating machinery, including ion and lactate transporters. Immunohistochemical staining of tumor tissue sections confirmed the increased expression of CAIX, HK2 and LDHA in ccRCC, validating the microarray data and supporting their potential as the energetic metabolism-related biomarkers of the ccRCC.

IL4 receptor α mediates enhanced glucose and glutamine metabolism to support breast cancer growth

The type II interleukin-4 receptor (IL4R) is expressed in human breast cancer, and in murine models thereof. It is activated by interleukin-4 (IL4), a cytokine produced predominantly by immune cells. Previously, we showed that expression of IL4Rα, a signaling component of IL4R, mediates enhanced metastatic growth through promotion of tumor cell survival and proliferation. In lymphocytes, these processes are supported by increased glucose and glutamine metabolism, and B lymphocyte survival is dependent upon IL4/IL4R-induced glucose metabolism. However, it is unknown whether IL4R-mediated metabolic reprogramming could support tumor growth. Here, we show that IL4Rα expression increases proliferation thus enhancing primary mammary tumor growth. In vitro, IL4-enhanced glucose consumption and lactate production in 4T1 cells was mediated by IL4Rα. Expression of the glucose transporter GLUT1 increased in response to IL4 in vitro, and enhanced GLUT1 expression was associated with the presence of IL4Rα in 4T1 mammary tumors in vivo. Although IL4 treatment did not induce changes in glucose metabolism in MDA-MB-231 human breast cancer cells, it increased expression of the main glutamine transporter, ASCT2, and enhanced glutamine consumption in both MDA-MB-231 and 4T1 cells. Pharmacologic inhibition of glutamine metabolism with compound 968 blocked IL4/IL4Rα-increased cell number in both cell lines. Our results demonstrate that IL4R mediates enhanced glucose and glutamine metabolism in 4T1 cancer cells, and that IL4-induced growth is supported by IL4/IL4R-enhanced glutamine metabolism in both human and murine mammary cancer cells. This highlights IL4Rα as a possible target for effective breast cancer therapy.

Evidence for heightened hexokinase II immunoexpression in hepatocyte dysplasia and hepatocellular carcinoma

BACKGROUND

Normal hepatocytes exhibit low-affinity hexokinase (glucokinase [HKIV]), but during oncogenesis, there is a switch from HKIV to HKII expression. The aims of this study were to compare the immunoexpression of HKII in non-dysplastic cirrhosis (NDC), liver cell change/dysplasia in cirrhosis (LCD), HCC, and normal liver control tissues, and to correlate HKII expression with clinical and histopathological parameters.

DESIGN

Immunohistochemistry was performed on a liver cancer progression tissue array consisting of specimens from explants with cirrhosis, including 45 tissue samples with HCC, 108 without HCC, 143 with LCD, and 8 normal liver control tissues. HKII expression was quantified as positive pixel counts/square millimeter (ppc/mm(2)) by image analysis.

RESULTS

There was a stepwise increase in HKII level from normal liver tissue to NDC, to LCD, and to HCC (p = 0.001). HKII levels were significantly higher in areas of LCD versus NDC (p ≤ 0.001), and in LCD and HCC versus NDC (p = 0.007). HKII levels were similar in LCD and HCC (p = 0.124). HKII levels were higher in grade 2-4 versus grade 1 HCCs (p = 0.044), and in pleomorphic versus non-pleomorphic HCC variants (p = 0.041). Higher levels of HKII expression in LCD and HCC versus NDC and in higher tumor grade remained significant in multivariate analysis.

CONCLUSIONS

Higher levels of HKII immunoexpression in LDC and HCC compared with NDC suggest that upregulation of HKII occurs during the process of hepatocarcinogenesis in humans. In HCC, higher levels of HKII are associated with more aggressive histological features.

Oncogene pathway activation in mammary tumors dictates FDG-PET uptake

Increased glucose utilization is a hallmark of human cancer that is used to image tumors clinically. In this widely used application, glucose uptake by tumors is monitored by positron emission tomography of the labeled glucose analogue 2[(18)F]fluoro-2-deoxy-D-glucose (FDG). Despite its widespread clinical use, the cellular and molecular mechanisms that determine FDG uptake--and that underlie the heterogeneity observed across cancers-remain poorly understood. In this study, we compared FDG uptake in mammary tumors driven by the Akt1, c-MYC, HER2/neu, Wnt1, or H-Ras oncogenes in genetically engineered mice, correlating it to tumor growth, cell proliferation, and expression levels of gene involved in key steps of glycolytic metabolism. We found that FDG uptake by tumors was dictated principally by the driver oncogene and was not independently associated with tumor growth or cellular proliferation. Oncogene downregulation resulted in a rapid decrease in FDG uptake, preceding effects on tumor regression, irrespective of the baseline level of uptake. FDG uptake correlated positively with expression of hexokinase-2 (HK2) and hypoxia-inducible factor-1α (HIF1α) and associated negatively with PFK-2b expression and p-AMPK. The correlation between HK2 and FDG uptake was independent of all variables tested, including the initiating oncogene, suggesting that HK2 is an independent predictor of FDG uptake. In contrast, expression of Glut1 was correlated with FDG uptake only in tumors driven by Akt or HER2/neu. Together, these results demonstrate that the oncogenic pathway activated within a tumor is a primary determinant of its FDG uptake, mediated by key glycolytic enzymes, and provide a framework to interpret effects on this key parameter in clinical imaging.

Prolactin-Stat5 signaling in breast cancer is potently disrupted by acidosis within the tumor microenvironment

INTRODUCTION

Emerging evidence in estrogen receptor-positive breast cancer supports the notion that prolactin-Stat5 signaling promotes survival and maintenance of differentiated luminal cells, and loss of nuclear tyrosine phosphorylated Stat5 (Nuc-pYStat5) in clinical breast cancer is associated with increased risk of antiestrogen therapy failure. However, the molecular mechanisms underlying loss of Nuc-pYStat5 in breast cancer remain poorly defined.

METHODS

We investigated whether moderate extracellular acidosis of pH 6.5 to 6.9 frequently observed in breast cancer inhibits prolactin-Stat5 signaling, using in vitro and in vivo experimental approaches combined with quantitative immunofluorescence protein analyses to interrogate archival breast cancer specimens.

RESULTS

Moderate acidosis at pH 6.8 potently disrupted signaling by receptors for prolactin but not epidermal growth factor, oncostatin M, IGF1, FGF or growth hormone. In breast cancer specimens there was mutually exclusive expression of Nuc-pYStat5 and GLUT1, a glucose transporter upregulated in glycolysis-dependent carcinoma cells and an indirect marker of lactacidosis. Mutually exclusive expression of GLUT1 and Nuc-pYStat5 occurred globally or regionally within tumors, consistent with global or regional acidosis. All prolactin-induced signals and transcripts were suppressed by acidosis, and the acidosis effect was rapid and immediately reversible, supporting a mechanism of acidosis disruption of prolactin binding to receptor. T47D breast cancer xenotransplants in mice displayed variable acidosis (pH 6.5 to 6.9) and tumor regions with elevated GLUT1 displayed resistance to exogenous prolactin despite unaltered levels of prolactin receptors and Stat5.

CONCLUSIONS

Moderate extracellular acidosis effectively blocks prolactin signaling in breast cancer. We propose that acidosis-induced prolactin resistance represents a previously unrecognized mechanism by which breast cancer cells may escape homeostatic control.

Prognostic impact of body mass index in patients with squamous cell carcinoma of the esophagus

PURPOSE

To clarify the prognostic impact of body mass index (BMI) in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Two hundred forty-three patients who underwent esophagectomy for ESCC from April 2005 through December 2010 were eligible. Prognoses of the patients were compared between groups stratified according to BMI. We also analyzed the survival difference using propensity score matching to adjust differences in staging and treatment.

RESULTS

Low, normal, and high BMI groups had 35, 177, and 31 patients, respectively. The low BMI group included more advanced cases than did the normal BMI group, while tumor stage was equivalent in the normal and high BMI groups. Disease-free survival of the low and high BMI groups was significantly worse than that of the normal BMI group (P<0.0001 between the low and normal BMI groups; P = 0.0076 between the normal and high BMI groups). Disease-free survival of the high BMI group was significantly worse than that of the normal BMI group in the propensity score-matched cohort (P = 0.0020). Multivariate analysis in this cohort demonstrated that high BMI was an independent prognostic factor (hazard ratio 2.949, 95% confidence interval, 1.132-7.683).

CONCLUSIONS

High BMI was an independent prognostic factor after curative esophagectomy for ESCC. Although further analysis is required to clarify the influence of overweight on the biological features of ESCC, glucose metabolism may be a therapeutic target for ESCC.

Glucose transporter 3 and 1 may facilitate high uptake of 18F-FDG in gastric schwannoma

Recently, some gastric schwannomas have been reported to have high uptake of FDG. However, Glut-1 was reported to be negative in gastric schwannomas tested. A 64-year-old female patient received a laparoscopic partial gastrectomy for a FDG PET-positive submucosal tumor (SUVmax 6.61). The resected tumor was diagnosed as a benign gastric schwannoma. Glut family immunohistochemical examination revealed diffuse positive expression of Glut-3 and partial positive expression of Glut-1. On the other hand, Glut-2 and Glut-4 expression in the tumor were negative. This case suggested that Glut-3 and Glut-1 expression were facilitators of high FDG uptake in the benign gastric schwannoma.