GLUT-1 expression in ovarian carcinoma: association with survival and response to chemotherapy

GLUT and HK: Two primary and essential key players in tumor glycolysis

Cancer cells reprogram their metabolism to become "glycolysis-dominant," which enables them to meet their energy and macromolecule needs and enhancing their rate of survival. This glycolytic-dominancy is known as the "Warburg effect", a significant factor in the growth and invasion of malignant tumors. Many studies confirmed that members of the GLUT family, specifically HK-II from the HK family play a pivotal role in the Warburg effect, and are closely associated with glucose transportation followed by glucose metabolism in cancer cells. Overexpression of GLUTs and HK-II correlates with aggressive tumor behaviour and tumor microenvironment making them attractive therapeutic targets. Several studies have proven that the regulation of GLUTs and HK-II expression improves the treatment outcome for various tumors. Therefore, small molecule inhibitors targeting GLUT and HK-II show promise in sensitizing cancer cells to treatment, either alone or in combination with existing therapies including chemotherapy, radiotherapy, immunotherapy, and photodynamic therapy. Despite existing therapies, viable methods to target the glycolysis of cancer cells are currently lacking to increase the effectiveness of cancer treatment. This review explores the current understanding of GLUT and HK-II in cancer metabolism, recent inhibitor developments, and strategies for future drug development, offering insights into improving cancer treatment efficacy.

Alteration of glucose metabolism and expression of glucose transporters in ovarian cancer

Aerobic glycolysis also known as the Warburg effect, remains a hallmark of various cancers, including ovarian cancer. Cancer cells undergo metabolic changes to sustain their tumorigenic properties and adapt to environmental conditions, such as hypoxia and nutrient starvation. Altered metabolic pathways not only facilitate ovarian cancer cells' survival and proliferation but also endow them to metastasize, develop resistance to chemotherapy, maintain cancer stem cell phenotype, and escape anti-tumor immune responses. Glucose transporters (GLUTs), which play a pivotal role as the rate-limiting step in glycolysis, are frequently overexpressed in a variety of tumors, including ovarian cancer. Multiple oncoproteins can regulate GLUT proteins, promoting tumor proliferation, migration, and metastasis, either dependent or independent of glycolysis. This review examines the alteration of GLUT proteins, particularly GLUT1, in ovarian cancer and its impact on cancer initiation, progression, and resistance to treatment. Additionally, it highlights the role of these proteins as biomarkers for diagnosis and prognosis in ovarian cancer, and delves into novel therapeutic strategies currently under development that target GLUT isoforms.

Metabolic reprogramming of three major nutrients in platinum-resistant ovarian cancer

Metabolic reprogramming is a phenomenon in which cancer cells alter their metabolic pathways to support their uncontrolled growth and survival. Platinum-based chemotherapy resistance is associated with changes in glucose metabolism, amino acid metabolism, fatty acid metabolism, and tricarboxylic acid cycle. These changes lead to the creation of metabolic intermediates that can provide precursors for the biosynthesis of cellular components and help maintain cellular energy homeostasis. This article reviews the research progress of the metabolic reprogramming mechanism of platinumbased chemotherapy resistance caused by three major nutrients in ovarian cancer.

The Role of Genetic Mutations in Mitochondrial-Driven Cancer Growth in Selected Tumors: Breast and Gynecological Malignancies

There is an increasing understanding of the molecular and cytogenetic background of various tumors that helps us better conceptualize the pathogenesis of specific diseases. Additionally, in many cases, these molecular and cytogenetic alterations have diagnostic, prognostic, and/or therapeutic applications that are heavily used in clinical practice. Given that there is always room for improvement in cancer treatments and in cancer patient management, it is important to discover new therapeutic targets for affected individuals. In this review, we discuss mitochondrial changes in breast and gynecological (endometrial and ovarian) cancers. In addition, we review how the frequently altered genes in these diseases (BRCA1/2, HER2, PTEN, PIK3CA, CTNNB1, RAS, CTNNB1, FGFR, TP53, ARID1A, and TERT) affect the mitochondria, highlighting the possible associated individual therapeutic targets. With this approach, drugs targeting mitochondrial glucose or fatty acid metabolism, reactive oxygen species production, mitochondrial biogenesis, mtDNA transcription, mitophagy, or cell death pathways could provide further tailored treatment.

Biomimetic Approach to Promote Cellular Uptake and Enhance Photoacoustic Properties of Tumor-Seeking Dyes

The attachment of glucose to drugs and imaging agents enables cancer cell targeting via interactions with GLUT1 overexpressed on the cell surface. While an added benefit of this modification is the solubilizing effect of carbohydrates, in the context of imaging agents, aqueous solubility does not guarantee decreased π-stacking or aggregation. The resulting broadening of the absorbance spectrum is a detriment to photoacoustic (PA) imaging since the signal intensity, accuracy, and image quality all rely on reliable spectral unmixing. To address this major limitation and further enhance the tumor-targeting ability of imaging agents, we have taken a biomimetic approach to design a multivalent glucose moiety (mvGlu). We showcase the utility of this new group by developing aza-BODIPY-based contrast agents boasting a significant PA signal enhancement greater than 11-fold after spectral unmixing. Moreover, when applied to targeting cancer cells, effective staining could be achieved with ultra-low dye concentrations (50 nM) and compared to a non-targeted analogue, the signal intensity was >1000-fold higher. Lastly, we employed the mvGlu technology to develop a logic-gated acoustogenic probe to detect intratumoral copper (i.e., Cu(I)), which is an emerging cancer biomarker, in a murine model of breast cancer. This exciting application was not possible using other acoustogenic probes previously developed for copper sensing.

Glycolysis Inhibition of Autophagy Drives Malignancy in Ovarian Cancer: Exacerbation by IL-6 and Attenuation by Resveratrol

Cancer cells drive the glycolytic process towards the fermentation of pyruvate into lactate even in the presence of oxygen and functioning mitochondria, a phenomenon known as the "Warburg effect". Although not energetically efficient, glycolysis allows the cancer cell to synthesize the metabolites needed for cell duplication. Autophagy, a macromolecular degradation process, limits cell mass accumulation and opposes to cell proliferation as well as to cell migration. Cancer cells corrupt cancer-associated fibroblasts to release pro-inflammatory cytokines, which in turn promote glycolysis and support the metastatic dissemination of cancer cells. In mimicking in vitro this condition, we show that IL-6 promotes ovarian cancer cell migration only in the presence of glycolysis. The nutraceutical resveratrol (RV) counteracts glucose uptake and metabolism, reduces the production of reactive oxygen species consequent to excessive glycolysis, rescues the mitochondrial functional activity, and stimulates autophagy. Consistently, the lack of glucose as well as its metabolically inert analogue 2-deoxy-D-glucose (2-DG), which inhibits hexokinase 2 (HK2), trigger autophagy through mTOR inhibition, and prevents IL-6-induced cell migration. Of clinical relevance, bioinformatic analysis of The Cancer Genome Atlas dataset revealed that ovarian cancer patients bearing mutated TP53 with low expression of glycolytic markers and IL-6 receptor, together with markers of active autophagy, display a longer overall survival and are more responsive to platinum therapy. Taken together, our findings demonstrate that RV can counteract IL-6-promoted ovarian cancer progression by rescuing glycolysis-mediated inhibition of autophagy and support the view that targeting Warburg metabolism can be an effective strategy to limit the risk for cancer metastasis.

Knock down of TIMP-2 by siRNA and CRISPR/Cas9 mediates diverse cellular reprogramming of metastasis and chemosensitivity in ovarian cancer

BACKGROUND

The endogenous tissue inhibitor of metalloproteinase-2 (TIMP-2), through its homeostatic action on certain metalloproteinases, plays a vital role in remodelling extracellular matrix (ECM) to facilitate cancer progression. This study investigated the role of TIMP-2 in an ovarian cancer cell line in which the expression of TIMP-2 was reduced by either siRNA or CRISPR/Cas9.

METHODS

OVCAR5 cells were transiently and stably transfected with either single or pooled TIMP-2 siRNAs (T2-KD cells) or by CRISPR/Cas9 under the influence of two distinct guide RNAs (gRNA1 and gRNA2 cell lines). The expression of different genes was analysed at the mRNA level by quantitative real time PCR (qRT-PCR) and at the protein level by immunofluorescence (IF) and western blot. Proliferation of cells was investigated by 5-Ethynyl-2'-deoxyuridine (EdU) assay or staining with Ki67. Cell migration/invasion was determined by xCELLigence. Cell growth in vitro was determined by 3D spheroid cultures and in vivo by a mouse xenograft model.

RESULTS

Approximately 70-90% knock down of TIMP-2 expression were confirmed in T2-KD, gRNA1 and gRNA2 OVCAR5 ovarian cancer cells at the protein level. T2-KD, gRNA1 and gRNA2 cells exhibited a significant downregulation of MMP-2 expression, but concurrently a significant upregulation in the expression of membrane bound MMP-14 compared to control and parental cells. Enhanced proliferation and invasion were exhibited in all TIMP-2 knocked down cells but differences in sensitivity to paclitaxel (PTX) treatment were observed, with T2-KD cells and gRNA2 cell line being sensitive, while the gRNA1 cell line was resistant to PTX treatment. In addition, significant differences in the growth of gRNA1 and gRNA2 cell lines were observed in in vitro 3D cultures as well as in an in vivo mouse xenograft model.

CONCLUSIONS

Our results suggest that the inhibition of TIMP-2 by siRNA and CRISPR/Cas-9 modulate the expression of MMP-2 and MMP-14 and reprogram ovarian cancer cells to facilitate proliferation and invasion. Distinct disparities in in vitro chemosensitivity and growth in 3D culture, and differences in tumour burden and invasion to proximal organs in a mouse model imply that selective suppression of TIMP-2 expression by siRNA or CRISPR/Cas-9 alters important aspects of metastasis and chemosensitivity in ovarian cancer.

The “Sweet Spot” of Targeting Tumor Metabolism in Ovarian Cancers

The objective of this review is to explore the metabolomic environment of epithelial ovarian cancer that contributes to chemoresistance and to use this knowledge to identify possible targets for therapeutic intervention. The Warburg effect describes increased glucose uptake and lactate production in cancer cells. In ovarian cancer, we require a better understanding of how cancer cells reprogram their glycogen metabolism to overcome their nutrient deficient environment and become chemoresistant. Glucose metabolism in ovarian cancer cells has been proposed to be influenced by altered fatty acid metabolism, oxidative phosphorylation, and acidification of the tumor microenvironment. We investigate several markers of altered metabolism in ovarian cancer including hypoxia-induced factor 1, VEGF, leptin, insulin-like growth factors, and glucose transporters. We also discuss the signaling pathways involved with these biomarkers including PI3K/AKT/mTOR, JAK/STAT and OXPHOS. This review outlines potential metabolic targets to overcome chemoresistance in ovarian cancer. Continued research of the metabolic changes in ovarian cancer is needed to identify and target these alterations to improve treatment approaches.

Importance of GLUT Transporters in Disease Diagnosis and Treatment

Facilitative sugar transporters (GLUTs) are the primary method of sugar uptake in all mammalian cells. There are 14 different types of those transmembrane proteins, but they transport only a handful of substrates, mainly glucose and fructose. This overlap and redundancy contradict the natural tendency of cells to conserve energy and resources, and has led researchers to hypothesize that different GLUTs partake in more metabolic roles than just sugar transport into cells. Understanding those roles will lead to better therapeutics for a wide variety of diseases and disorders. In this review we highlight recent discoveries of the role GLUTs play in different diseases and disease treatments.

Metabolic profile of the Warburg effect as a tool for molecular prognosis and diagnosis of cancer

INTRODUCTION

Adaptations of eukaryotic cells to environmental changes are important for their survival. However, under some circumstances, microenvironmental changes promote that eukaryotic cells utilize a metabolic signature resembling a unicellular organism named the Warburg effect. Most cancer cells share the Warburg effect displaying lactic fermentation and high glucose uptake. The Warburg effect also induces a metabolic rewiring stimulating glutamine consumption and lipid synthesis, also considered cancer hallmarks. Amino acid metabolism alteration due to the Warburg effect increases plasma levels of proline and branched-chain amino acids in several cancer types. Proline and lipids are probably used as electron transfer molecules in carcinogenic cells. In addition, branched-chain amino acids fuel the Krebs cycle, protein synthesis, and signaling in cancer cells.

AREAS COVERED

This review covers how metabolomics studies describe changes in some metabolites and proteins associated with the Warburg effect and related metabolic pathways.

EXPERT OPINION

In this review, we analyze the metabolic signature of the Warburg effect and related phenotypes and propose some Warburg effect-related metabolites and proteins (lactate, glucose uptake, glucose transporters, glutamine, branched-chain amino acids, proline, and some lipogenic enzymes) as promising cancer biomarkers.

Glucose transporters as markers of diagnosis and prognosis in cancer diseases

The primary metabolic substrate for cells is glucose, which acts as both a source of energy and a substrate in several processes. However, being lipophilic, the cell membrane is impermeable to glucose and specific carrier proteins are needed to allow transport. In contrast to normal cells, cancer cells are more likely to generate energy by glycolysis; as this process generates fewer molecules of adenosine triphosphate (ATP) than complete oxidative breakdown, more glucose molecules are needed. The increased demand for glucose in cancer cells is satisfied by overexpression of a number of glucose transporters, and decreased levels of others. As specific correlations have been observed between the occurrence of cancer and the expression of glucose carrier proteins, the presence of changes in expression of glucose transporters may be treated as a marker of diagnosis and/or prognosis for cancer patients.

Targeting of PFKFB3 with miR-206 but not mir-26b inhibits ovarian cancer cell proliferation and migration involving FAK downregulation

Few studies explored the role of microRNAs (miRNAs) in the post-transcriptional regulation of glycolytic proteins and downstream effectors in ovarian cancer cells. We recently showed that the functional activation of the cytoskeletal regulator FAK in endothelial cells is fostered by the glycolytic enhancer 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3). We tested the hypothesis that miR-206 and mir-26b, emerging onco-suppressors targeting PFKFB3 in estrogen-dependent tumors, would regulate proliferation and migration of serous epithelial ovarian cancer (EOC) cells via common glycolytic proteins, i.e., GLUT1 and PFKFB3, and downstream FAK. PFKFB3 was overexpressed in SKOV3, and its pharmacological inhibition with 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO) significantly reduced cell proliferation and motility. Both miR-206 and miR-26b directly targeted PFKFB3 as evaluated by a luciferase reporter assay. However, endogenous levels of miR-26b were higher than those of miR-206, which was barely detectable in SKOV3 as well as OVCAR5 and CAOV3 cells. Accordingly, only the anti-miR-26b inhibitor concentration-dependently increased PFKFB3 levels. While miR-206 overexpression impaired proliferation and migration by downregulating PFKFB3 levels, the decreased PFKFB3 protein levels related to miR-26 overexpression had no functional consequences in all EOC cell lines. Finally, consistent with the migration outcome, exogenous miR-206 and miR-26b induced opposite effects on the levels of total FAK and of its phosphorylated form at Tyr576/577. 3PO did not prevent miR-26b-induced SKOV3 migration. Overall, these results support the inverse relation between endogenous miRNA levels and their tumor-suppressive effects and suggest that restoring miR-206 expression represents a potential dual anti-PFKFB3/FAK strategy to control ovarian cancer progression.

Vitamin C and cancer risk and treatment

Vitamin C (L-ascorbic acid) works as a strong reductant, radical scavenger, and protector of cell membranes against primary peroxidative damage in tissues and in the extracellular fluid. L-ascorbic acid is involved in the synthesis of collagen and many other biologically relevant substances, enzyme activity, xenobiotic detoxification, and prevention of forming carcinogenic nitrosamines. It also plays a role in the immune system. Numerous data indicate that cancer patients suffer from vitamin C deficiency. Studies show that people with a low vitamin C intake have an increased risk of head and neck cancers as well as lung, gastric, pancreatic, cervical, rectal, or breast cancer. On the other hand, there is no clinical evidence to support the thesis that antioxidant supplements (including vitamin C) prevent cancer. Observational trials investigating high doses of intravenous L-ascorbic acid in previously treated cancer patients have shown that it allows an increase in quality of life and may improve physical, mental, and emotional functions, as well as reducing adverse effects of standard anticancer treatment, including fatigue, nausea, vomiting, and appetite loss. So far, there were a few randomized controlled trials and they have not reported any statistically significant improvements in the overall or progression-free survival with vitamin C, as compared to the control arm. However, preclinical data indicating a role of L-ascorbic acid in modulation of immune response and its involvement in epigenome remodeling suggest its new potential clinical applications in cancer patients, especially in combination with immunotherapy. It seems reasonable to further investigate the value of vitamin C as a supportive treatment or in combination with anticancer targeted therapy.

Glucose deprivation enhances resistance to paclitaxel via ELAVL2/4-mediated modification of glycolysis in ovarian cancer cells

The dysregulation of glycolysis regardless of oxygen availability is one of the major characteristics of cancer cells. While the drug resistance of ovarian cancer cells has been extensively studied, the molecular mechanism of anticancer drug resistance under low-glucose conditions remains unknown. In this study, we investigated the pathway mediating drug resistance under low-glucose conditions by examining the relationship between embryonic lethal abnormal vision Drosophila homolog-like (ELAVL) protein and glycolysis-related enzymes. Ovarian cancer cells resistant to 2.5 nM paclitaxel were exposed to low-glucose media for 2 weeks, and the expression levels of ELAVL2, ELAVL4, glycolytic enzymes, and drug resistance-related proteins were elevated to levels comparable to those in cells resistant to 100 nM paclitaxel. Gene silencing of ELAVL2/4 using small interfering RNA prevented the upregulation of glycolysis-related enzymes, reduced lactate production, and sensitized 2.5 nM paclitaxel-resistant ovarian cancer cells to anticancer agents under hypoglycemic conditions. Furthermore, pharmacological inhibition of glycolytic enzymes with 2-deoxyglucose, a specific inhibitor of glycolysis, triggered caspase-dependent apoptosis, reduced lactate generation, and blocked the expression of drug resistance-related proteins under low-glucose conditions. These results suggest that the level of ELAVL2/4 is responsible for the development of chemoresistance through activation of the glycolysis pathway under glucose deprivation conditions.

Effect of the structure of ginsenosides on the in vivo fate of their liposomes

To utilize the multiple functions and give full play of ginsenosides, a variety of ginsenosides with different structures were prepared into liposomes and evaluated for their effect on the stability, pharmacokinetics and tumor targeting capability of liposomes. The results showed that the position and number of glycosyl groups of ginsenosides have significant effect on the in vitro and in vivo properties of their liposomes. The pharmacokinetics of ginsenosides liposomes indicated that the C-3 sugar group of ginsenosides is beneficial to their liposomes for longer circulation in vivo. The C-3 and C-6 glycosyls can enhance the uptake of their liposomes by 4T1 cells, and the glycosyls at C-3 position can enhance the tumor active targeting ability significantly, based on the specific binding capacity to Glut 1 expressed on the surface of 4T1 cells. According to the results in the study, ginsenoside Rg3 and ginsenoside Rh2 are potential for exploiting novel liposomes because of their cholesterol substitution, long blood circulation and tumor targeting capabilities. The results provide a theoretical basis for further development of ginsenoside based liposome delivery systems.

The Sustainability of Energy Conversion Inhibition for Tumor Ferroptosis Therapy and Chemotherapy

The hyperactive energy metabolism mostly contributes the tumor cells growth and proliferation. Herein, the intelligent nanoparticles (P-B-D NPs) obtained by loading BAY-876 and doxorubicin (Dox)-Duplex into nanoparticles composed of disulfide bond (SS) containing polymer are reported, which provide an efficient resistance of tumor cells energy metabolism and tumor growth to conquer malignant tumor. In response to the reducing microenvironment of tumor tissue, the SS bond can be disintegrated by intracellular glutathione to block the synthesis of lipid repair enzyme-glutathione peroxidase 4 for ferroptosis therapy. More importantly, the released BAY-876 can inhibit the functionality of glucose transporter 1, restricting the glucose uptake of tumor cells to a low energy metabolism status. Meanwhile, Dox-Duplex can interact with ATP to reduce intracellular ATP content and release Dox to kill tumor cells. Collectively, this work offers a new idea for restricting tumor cells energy metabolism to inhibit their proliferation.

Determining the immunohistochemical expression of GLUT1 in renal cell carcinoma using the HSCORE method

The aim of the present study was to compare the immunohistochemical expression of glucose transporter 1 (GLUT1) between the most common histological types of renal cell carcinoma (RCC), and to determine whether a correlation between GLUT1 expression and nuclear grade or tumor size exists. A total of 19 RCC samples were selected for the study, consisting of 8 clear cell (cc)RCC and 11 non-ccRCC tissues. Immunohistochemistry for GLUT1 was performed on formalin-fixed and paraffin-embedded sections using GLUT1 antibodies. All data analyses were performed using the MedCalc software. There was a higher immunohistochemical expression of GLUT1 in the ccRCC group compared with the non-cc group, but there was no difference in GLUT1 expression between groups of RCCs with differing nuclear grades. No significant correlation between GLUT1 expression and tumor size was found. The higher immunohistochemical expression of GLUT1 in ccRCC may be a contributing factor to the clinical characteristics and behavior of that group of carcinomas. These results suggest that GLUT1 expression cannot be used as a prognostic factor for RCC, but it may be used as a predictive factor in the future.

The Role of Glucose Transporters in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a prevalent malignancy associated with a poor prognosis. The Warburg effect can be observed in OSCCs, with tumours requiring a robust glucose supply. Glucose transporters (GLUTs) and sodium-glucose co-transporters (SGLTs) are overexpressed in multiple malignancies, and are correlated with treatment resistance, clinical factors, and poor overall survival (OS). We conducted a systematic review to evaluate the differences in GLUT/SGLT expression between OSCC and normal oral keratinocytes (NOK), as well as their role in the pathophysiology and prognosis of OSCC. A total of 85 studies were included after screening 781 papers. GLUT-1 is regularly expressed in OSCC and was found to be overexpressed in comparison to NOK, with high expression correlated to tumour stage, treatment resistance, and poor prognosis. No clear association was found between GLUT-1 and tumour grade, metastasis, and fluorodeoxyglucose (FDG) uptake. GLUT-3 was less thoroughly studied but could be detected in most samples and is generally overexpressed compared to NOK. GLUT-3 negatively correlated with overall survival (OS), but there was insufficient data for correlations with other clinical factors. Expression of GLUT-2/GLUT-4/GLUT-8/GLUT-13/SGLT-1/SGLT-2 was only evaluated in a small number of studies with no significant differences detected. GLUTs 7 and 14 have never been evaluated in OSCC. In conclusion, the data demonstrates that GLUT-1 and GLUT-3 have a role in the pathophysiology of OSCC and represent valuable biomarkers to aid OSCC diagnosis and prognostication. Other GLUTs are comparatively understudied and should be further analysed because they may hold promise to improve patient care.

A pancancer overview of FBN1, asprosin and its cognate receptor OR4M1 with detailed expression profiling in ovarian cancer

Ovarian cancer affects >295,000 women worldwide and is the most lethal of gynaecological malignancies. Often diagnosed at a late stage, current research efforts seek to further the molecular understanding of its aetiopathogenesis and the development of novel biomarkers. The present study investigated the expression levels of the glucogenic hormone asprosin [encoded by fibrillin-1 (FBN1)], and its cognate receptor, olfactory receptor 4M1 (OR4M1), in ovarian cancer. A blend of in silico open access The Cancer Genome Atlas data, as well as in vitro reverse transcription-quantitative PCR (RT-qPCR), immunohistochemistry and immunofluorescence data were used. RT-qPCR revealed expression levels of OR4M1 and FBN1 in clinical samples and in ovarian cancer cell lines (SKOV-3, PEO1, PEO4 and MDAH-2774), as well as the normal human ovarian surface epithelial cell line (HOSEpiC). Immunohistochemical staining of a tissue microarray was used to identify the expression levels of OR4M1 and asprosin in ovarian cancer samples of varying histological subtype and grade, including clear cell carcinoma, serous ovarian cancer and mucinous adenocarcinoma. Immunofluorescence analysis revealed asprosin expression in SKOV-3 and HOSEpiC cells. These results demonstrated the expression of both asprosin and OR4M1 in normal and malignant human ovarian tissues. This research invokes further investigation to advance the understanding of the role of asprosin and OR4M1 within the ovarian tumour microenvironment.

Recent advancements in therapeutic targeting of the Warburg effect in refractory ovarian cancer: A promise towards disease remission

Epithelial ovarian cancer, the most lethal gynecological malignancy, is diagnosed at advanced stage, recurs and displays chemoresistance to standard chemotherapeutic regimen of taxane/platinum drugs. Despite development of recent therapeutic approaches including poly-ADP ribose polymerase inhibitors, this fatal disease is diagnosed at advanced stage and heralds strategies for early detection and improved treatment. Recent literature suggests that high propensity of ovarian cancer cells to consume and metabolize glucose via glycolysis even in the presence of oxygen (the 'Warburg effect') can significantly contribute to disease progression and chemoresistance and hence, it has been exploited as novel drug target. This review focuses on the molecular cues of aberrant glycolysis as drivers of chemo-resistance and aggressiveness of recurrent ovarian cancer. Furthermore, we discuss the status quo of small molecule inhibition of aerobic glycolysis and significance of metabolic coupling between cancer cells and tumor microenvironment as novel therapeutic interventions against this lethal pathology.

Comparing prognostic factors of Glut-1 expression and maximum standardized uptake value by FDG-PET in patients with resectable pancreatic cancer

BACKGROUND

This study aimed to assess the prognostic values of preoperative maximum standardized uptake value (SUVmax) of primary pancreatic tumors and Glut-1 expression in patients with resectable pancreatic ductal adenocarcinoma (R-PDAC), and to investigate whether Glut-1 expression is more effective than SUVmax in predicting survival in patients with R-PDAC.

METHODS

We investigated 101 R-PDAC patients who underwent pancreatectomy for pancreatic cancer treatment. SUVmax analyzed through ¹⁸F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT), and Glut-1 expression, were assessed for predicting the prognosis of patients with R-PDAC.

RESULTS

In patients with R-PDAC, the high SUVmax group (≥4.25) had significantly shorter overall survival (OS) and disease-free survival (DFS) than the low SUVmax group (＜4.25). Surprisingly, Glut-1 expression was not significantly correlated with SUVmax. Moreover, the high Glut-1 expression group, which was related to higher levels of CA 19-9, had significantly shorter OS and DFS than the low Glut-1 expression group. Furthermore, among the high SUVmax group, OS and DFS were significantly shorter in the high Glut-1 expression group. Multivariate analyses revealed that Glut-1 overexpression was an independent prognostic factor in patients with R-PDAC. Glut-1 knockdown also induced cell cycle arrest in PDAC cells in vitro.

CONCLUSIONS

The study determined that Glut-1 overexpression is a more powerful prognostic factor than SUVmax for predicting OS and higher risk of recurrence in R-PDAC patients. Glut-1 overexpression is also more likely to be associated with malignant activity in PDAC patients.

Regulators of glucose uptake in thyroid cancer cell lines

Abstract

Thyroid cancer is the most common sort of endocrine-related cancer with more prevalent in women and elderly individuals which has quickly widespread expansion in worldwide over the recent decades. Common features of malignant thyroid cells are to have accelerated metabolism and increased glucose uptake to optimize their energy supply which provides a fundamental advantage for growth. In tumor cells the retaining of required energy charge for cell survival is imperative, indeed glucose transporters are enable of promoting of this task. According to this relation it has been reported the upregulation of glucose transporters in various types of cancers. Human studies indicated that poor survival can be occurred following the high levels of GLUT1 expression in tumors. GLUT-1 and GLUT3 are the glucose transporters which seems to be mainly engaged with the oncogenesis of thyroid cancer and their expression in malignant tissues is much more than in the normal one. They are promising targets for the advancement of anticancer strategies. The lack of oncosuppressors have dominant effect on the membrane expression of GLUT1 and glucose uptake. Overexpression of hypoxia inducible factors have been additionally connected with distant metastasis in thyroid cancers which mediates transcriptional regulation of glycolytic genes including GLUT1 and GLUT3. Though the physiological role of the thyroid gland is well illustrated, but the metabolic regulations in thyroid cancer remain evasive. In this study we discuss proliferation pathways of the key regulators and signaling molecules such as PI3K-Akt, HIF-1, MicroRNA, PTEN, AMPK, BRAF, c-Myc, TSH, Iodide and p53 which includes in the regulation of GLUTs in thyroid cancer cells. Incidence of deregulations in cellular energetics and metabolism are the most serious signs of cancers. In conclusion, understanding the mechanisms of glucose transportation in normal and pathologic thyroid tissues is critically important and could provide significant insights in science of diagnosis and treatment of thyroid disease.

KDM4B facilitates colorectal cancer growth and glucose metabolism by stimulating TRAF6-mediated AKT activation

Background

Histone lysine demethylase 4B (KDM4B) has been implicated in various pathological processes and human diseases. Glucose metabolism is the main pattern of energy supply in cells and its dysfunction is closely related to tumorigenesis. Recent study shows that KDM4B protects against obesity and metabolic dysfunction. We realized the significant role of KDM4B in metabolism. However, the role of KDM4B in glucose metabolism remains unclear. Here, we sought to delineate the role and mechanism of KDM4B in glucose metabolism in colorectal cancer (CRC).

Methods

We first analyzed the role of KDM4B in glucose uptake and CRC growth. We then investigated the consequences of KDM4B inhibition on the expression of GLUT1 and AKT signaling, also explored the underlying mechanism. Finally, we detected the mechanism in vivo and assessed the potential correlation between the expression of KDM4B and CRC prognosis.

Results

We found that KDM4B promoted glucose uptake and ATP production by regulating the expression of GLUT1 via the AKT signaling pathway. KDM4B could interact with TRAF6 and promote TRAF6-mediated ubiquitination of AKT for AKT activation. Furthermore, we demonstrated that KDM4B was overexpressed in CRC specimens and high level of KDM4B was associated with a poor survival rate in CRC patients.

Conclusions

These findings reveal that KDM4B plays an important role in promoting CRC progression by enhancing glucose metabolism.

Sugar Modification Enhances Cytotoxic Activity of PAMAM-Doxorubicin Conjugate in Glucose-Deprived MCF-7 Cells - Possible Role of GLUT1 Transporter

Purpose

In order to overcome the obstacles and side effects of classical chemotherapy, numerous studies have been performed to develop the treatment based on targeted transport of active compounds directly to the site of action. Since tumor cells are featured with intensified glucose metabolism, we set out to develop innovative, glucose-modified PAMAM dendrimer for the delivery of doxorubicin to breast cancer cells.

Methods

PAMAM-dox-glc conjugate was synthesized and characterized by ¹H NMR, FT-IR, size and zeta potential measurements. The drug release rate from conjugate was evaluated by dialysis under different pH conditions. The expression level of GLUT family receptors in cells cultured in full and glucose-deprived medium was evaluated by quantitative real-time RT-PCR and flow cytometry. The cytotoxicity of conjugate in presence or absence of GLUT1 inhibitors was determined by MTT assay.

Results

We showed that PAMAM-dox-glc conjugate exhibits pH-dependent drug release and increased cytotoxic activity compared to free drug in cells cultured in medium without glucose. Further, we proved that these cells overexpress transporters of GLUT family. The toxic effect of conjugate was eliminated by the application of specific GLUT1 inhibitors.

Conclusion

Our findings revealed that the glucose moiety plays a crucial role in the recognition of cells with high expression of GLUT receptors. By selectively blocking GLUT1 transporter we showed its importance for the cytotoxic activity of PAMAM-dox-glc conjugate. These results suggest that PAMAM-glucose formulations may constitute an efficient platform for the specific delivery of anticancer drugs to tumor cells overexpressing transporters of GLUT family.

Electronic supplementary material

The online version of this article (10.1007/s11095-019-2673-9) contains supplementary material, which is available to authorized users.

Glut 1 in Cancer Cells and the Inhibitory Action of Resveratrol as A Potential Therapeutic Strategy

An important hallmark in cancer cells is the increase in glucose uptake. GLUT1 is an important target in cancer treatment because cancer cells upregulate GLUT1, a membrane protein that facilitates the basal uptake of glucose in most cell types, to ensure the flux of sugar into metabolic pathways. The dysregulation of GLUT1 is associated with numerous disorders, including cancer and metabolic diseases. There are natural products emerging as a source for inhibitors of glucose uptake, and resveratrol is a molecule of natural origin with many properties that acts as antioxidant and antiproliferative in malignant cells. In the present review, we discuss how GLUT1 is involved in the general scheme of cancer cell metabolism, the mechanism of glucose transport, and the importance of GLUT1 structure to understand the inhibition process. Then, we review the current state-of-the-art of resveratrol and other natural products as GLUT1 inhibitors, focusing on those directed at treating different types of cancer. Targeting GLUT1 activity is a promising strategy for the development of drugs aimed at treating neoplastic growth.

Performance of pre-treatment ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography for detecting metastasis in ovarian cancer: a systematic review and meta-analysis

OBJECTIVE

We describe a systematic review and meta-analysis of the performance of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for detecting metastasis in ovarian cancer.

METHODS

MEDLINE and Embase were searched for diagnostic accuracy studies that used ¹⁸F-FDG PET or PET/CT for pre-treatment staging, using surgical findings as the reference standard. Sensitivities and specificities were pooled and plotted in a hierarchic summary receiver operating characteristic plot. Potential causes of heterogeneity were explored through sensitivity analyses.

RESULTS

Eight studies with 594 patients were included. The overall pooled sensitivity and specificity for metastasis were 0.72 (95% confidence interval [CI]=0.61-0.81) and 0.93 (95% CI=0.85-0.97), respectively. There was considerable heterogeneity in sensitivity (I²=97.57%) and specificity (I²=96.74%). In sensitivity analyses, studies that used laparotomy as the reference standard showed significantly higher sensitivity and specificity (0.77; 95% CI=0.67-0.87 and 0.96; 95% CI=0.92-0.99, respectively) than those including diagnostic laparoscopy (0.62; 95% CI=0.46-0.77 and 0.84; 95% CI=0.69-0.99, respectively). Higher specificity was shown in studies that confirmed surgical findings by pathologic evaluation (0.95; 95% CI=0.90-0.99) than in a study without pathologic confirmation (0.69; 95% CI=0.24-1.00). Studies with a lower prevalence of the FDG-avid subtype showed higher specificity (0.97; 95% CI=0.94-1.00) than those with a greater prevalence (0.89; 95% CI=0.80-0.97).

CONCLUSION

Pre-treatment ¹⁸F-FDG PET/CT shows moderate sensitivity and high specificity for detecting metastasis in ovarian cancer. With its low false-positive rate, it can help select surgical approaches or alternative treatment options.

Tumour expressions of hypoxic markers predict the response to neo-adjuvant chemotherapy in children with inoperable rhabdomyosarcoma

Objective: The study was to assess whether tumour expressions of hypoxia-inducible factor (HIF)-1α, glucose transporter (GLUT)-1, carbonic anhydrase (CA) IX and vascular endothelial growth factor (VEGF) predict response to neo-adjuvant chemotherapy (naCHT) in children with inoperable rhabdomyosarcoma (RMS). Methods: Immunohistochemical expressions of hypoxia markers were determined semi-quantitatively in tumour tissue microarray of 46 patients with embryonal RMS (RME) and 20 with alveolar (RMA), treated with CWS protocols (1992-2013). Results: In paediatric RME, response to naCHT was influenced significantly by tumour expression of CA IX and GLUT-1. Patients with RMA with low expressions of analysed markers responded well to naCHT, while all poor-responders expressed highly hypoxia markers. Only 5.88% of RMA and 11.11% of RME tumours did not express any of the proteins. In both RME and RMA subgroups, most poor-responders demonstrated simultaneous high expression of ≥3 markers, while most patients expressing ≤2 markers responded well to naCHT. In the whole cohort, co-expression of ≥3 markers, was the only independent factor predicting poor-response to chemotherapy (odds ratio 14.706; 95% CI 1.72-125.75; p = 0.014). Conclusions: Immunohistochemical expression pattern of four endogenous markers of hypoxia, in tumour tissue at diagnosis, emerges as a promising tool to predict response to naCHT in children with inoperable RMS.

Anti-tumor effect of aloe-emodin on cervical cancer cells was associated with human papillomavirus E6/E7 and glucose metabolism

Background：Aloe-emodin, an anthraquinone present in aloe latex, has been shown to have anti-proliferative properties in cervical cancer disease, all cases of which are almost caused by human papillomavirus (HPV), with the products of E6/E7. It is suggested that aloe-emodin may play an important role in HPV-induced cervical cancer cells.

Methods：Hela and SiHa cells were treated with various concentrations of aloe-emodin. MTT assay and flow cytometry were used to identify the cell growth and apoptosis. The expressions of HPV E6, E7 and GLUT1 (glucose transporter-1) were detected by real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot (WB). The glucose uptake, lactate production and ATP production in HeLa and SiHa cells were also investigated.

Result：The results indicate that aloe-emodin promoted the apoptosis of HeLa and SiHa cells and decreased the expressions of HPV-related protein E6 and E7. Furthermore, aloe-emodin inhibited glucose metabolism by reducing GLUT1 expression. Overexpression of GLUT1 significantly weakened the apoptosis induced by aloe-emodin in HeLa cells.

Conclusion：In this study, we found that aloe-emodin induce apoptosis of cervical cancer cells, which was associated with HPV E6 and E7 and glucose metabolism.

Diurnal profile of interstitial glucose following dexamethasone prophylaxis for chemotherapy treatment of gynaecological cancer

AIMS

Hyperglycaemia, a side-effect of acute glucocorticoid exposure, is associated with poor outcome in those undergoing chemotherapy. The incidence, risk factors and diurnal profile of glucocorticoid-induced glucose dysregulation in the context of chemotherapy treatment remain incompletely understood.

METHODS

Blinded continuous interstitial glucose monitoring was performed on 16 women without diabetes for 24 h prior to and 5 days following carboplatin/paclitaxel chemotherapy combined with dexamethasone treatment for gynaecological cancer. At the end of the treatment period, glucose data were analysed and integrated with baseline metabolic and anthropomorphic variables.

RESULTS

15/16 (94%) women exhibited elevated glucose levels (> 11.1 mmol/l). Peak glucose levels were highest on the day of treatment (median 14.45 mmol/l, range 10.2-22.2 mmol/l) and total time spent with an elevated interstitial glucose level was highly variable (median 3.6 h, range 0.0-55.1 h). Peak interstitial glucose levels occurred predominantly, but not exclusively, in the afternoon (13.00-15.00) and evening (19.00-22.00); however elevated levels were noted throughout the 24-h period. Baseline HbA_1c was independently associated with severity and duration of elevated glucose levels in a regression adjusted for baseline BMI.

CONCLUSIONS

These data report for the first time that high glucose levels are encountered by nearly all women following this regimen, the severity and duration of which are independently associated with HbA_1c . Further work is required to determine if controlling glucose levels during treatment influences outcome.

MiR-1204 promotes ovarian squamous cell carcinoma growth by increasing glucose uptake

MiR-1204 has been recently identified as an oncogenic miRNA in breast cancer. Our study aims to investigate the role of miR-1204 in ovarian squamous cell carcinoma. Expression of miR-1204 and glucose transporter 1 in ovarian biopsies and plasma of both OC patients and healthy controls was detected by qRT-PCR. Correlations between patients' clinicopathological data were analyzed by Chi-square test. MiR-1204 overexpression OC cell lines were established. Expression of GLUT-1 protein was detected by western blot. Glucose uptake was measured by glucose uptake assay. Cell proliferation was detected by CCK-8 assay. We found that miR-1204 expression was significantly correlated with tumor size. Expression levels of miR-1204 and GLUT-1 were significantly high in OC patients. Expression levels of miR-1204 were positively correlated with expression levels of GLUT-1 in OC patients. MiR-1204 overexpression significantly promoted GLUT-1 expression, glucose uptake and cell proliferation. MiR-1204 may promote ovarian squamous cell carcinoma growth by increasing glucose uptake.

Expression of glycolytic enzymes in ovarian cancers and evaluation of the glycolytic pathway as a strategy for ovarian cancer treatment

BACKGROUND

Novel therapeutic approaches are required to treat ovarian cancer and dependency on glycolysis may provide new targets for treatment. This study sought to investigate the variation of expression of molecular components (GLUT1, HKII, PKM2, LDHA) of the glycolytic pathway in ovarian cancers and the effectiveness of targeting this pathway in ovarian cancer cell lines with inhibitors.

METHODS

Expression of GLUT1, HKII, PKM2, LDHA were analysed by quantitative immunofluorescence in a tissue microarray (TMA) analysis of 380 ovarian cancers and associations with clinicopathological features were sought. The effect of glycolysis pathway inhibitors on the growth of a panel of ovarian cancer cell lines was assessed by use of the SRB proliferation assay. Combination studies were undertaken combining these inhibitors with cytotoxic agents.

RESULTS

Mean expression levels of GLUT1 and HKII were higher in high grade serous ovarian cancer (HGSOC), the most frequently occurring subtype, than in non-HGSOC. GLUT1 expression was also significantly higher in advanced stage (III/IV) ovarian cancer than early stage (I/II) disease. Growth dependency of ovarian cancer cells on glucose was demonstrated in a panel of ovarian cancer cell lines. Inhibitors of the glycolytic pathway (STF31, IOM-1190, 3PO and oxamic acid) attenuated cell proliferation in platinum-sensitive and platinum-resistant HGSOC cell line models in a concentration dependent manner. In combination with either cisplatin or paclitaxel, 3PO (a novel PFKFB3 inhibitor) enhanced the cytotoxic effect in both platinum sensitive and platinum resistant ovarian cancer cells. Furthermore, synergy was identified between STF31 (a novel GLUT1 inhibitor) or oxamic acid (an LDH inhibitor) when combined with metformin, an inhibitor of oxidative phosphorylation, resulting in marked inhibition of ovarian cancer cell growth.

CONCLUSIONS

The findings of this study provide further support for targeting the glycolytic pathway in ovarian cancer and several useful combinations were identified.

PTEN dephosphorylates AKT to prevent the expression of GLUT1 on plasmamembrane and to limit glucose consumption in cancer cells

GLUT1 is the facilitative transporter playing the major role in the internalization of glucose. Basally, GLUT1 resides on vesicles located in a para-golgian area, and is translocated onto the plasmamembrane upon activation of the PI3KC1-AKT pathway. In proliferating cancer cells, which demand a high quantity of glucose for their metabolism, GLUT1 is permanently expressed on the plasmamembrane. This is associated with the abnormal activation of the PI3KC1-AKT pathway, consequent to the mutational activation of PI3KC1 and/or the loss of PTEN. The latter, in fact, could antagonize the phosphorylation of AKT by limiting the availability of Phosphatidylinositol (3,4,5)-trisphosphate. Here, we asked whether PTEN could control the plasmamembrane expression of GLUT1 also through its protein-phosphatase activity on AKT. Experiments of co-immunoprecipitation and in vitro de-phosphorylation assay with homogenates of cells transgenically expressing the wild type or knocked-down mutants (lipid-phosphatase, protein-phosphatase, or both) isoforms demonstrated that indeed PTEN physically interacts with AKT and drives its dephosphorylation, and so limiting the expression of GLUT1 at the plasmamembrane. We also show that growth factors limit the ability of PTEN to dephosphorylate AKT. Our data emphasize the fact that PTEN acts in two distinct steps of the PI3k/AKT pathway to control the expression of GLUT1 at the plasmamembrane and, further, add AKT to the list of the protein substrates of PTEN.

Glucose transporter-1 as an independent prognostic marker for cancer: a meta-analysis

Objective

Glucose transporter-1 (GLUT-1) as the major glucose transporter present in human cells is found overexpressed in a proportion of human malignancies. This meta-analysis is attempted to assess the prognostic significance of GLUT-1 for survival in various cancers.

Materials and Methods

We conducted an electronic search using the databases PubMed, Embase and Web of Science, from inception to Oct 20th, 2016. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

Results

Fourty-one studies with a total of 4794 patients were included. High GLUT-1 expression was significantly associated with poorer prognosis [overall survival: HR = 1.833 (95% CI: 1.597–2.069, P < 0.0001); disease-free survival: HR = 1.838 (95% CI: 1.264–2.673, P < 0.0001); progression-free survival: HR = 2.451 (95% CI: 1.668–3.233, P < 0.0001); disease specific survival: HR = 1.96 (95% CI: 1.05–2.871, P < 0.0001)].

Conclusions

High GLUT-1 expression may be an independent prognostic marker to predict poor survival in various types of cancers. Further clinical trials with high quality need to be conducted to confirm our conclusion.

Implications of Resveratrol on Glucose Uptake and Metabolism

Resveratrol—a polyphenol of natural origin—has been the object of massive research in the past decade because of its potential use in cancer therapy. However, resveratrol has shown an extensive range of cellular targets and effects, which hinders the use of the molecule for medical applications including cancer and type 2 diabetes. Here, we review the latest advances in understanding how resveratrol modulates glucose uptake, regulates cellular metabolism, and how this may be useful to improve current therapies. We discuss challenges and findings regarding the inhibition of glucose uptake by resveratrol and other polyphenols of similar chemical structure. We review alternatives that can be exploited to improve cancer therapies, including the use of other polyphenols, or the combination of resveratrol with other molecules and their impact on glucose homeostasis in cancer and diabetes.

Validity and clinical impact of glucose transporter 1 expression in colorectal cancer

BACKGROUND/AIM

There is no doubt that colorectal cancer (CRC) poses a major threat to public health worldwide, and despite improvement in managements, prognosis still remains an irritating question with no definite answer. Being a fundamental player in cancer metabolism, glucose transporter 1 (GLUT1) could be utilized as a prognostic biomarker that could fuel development of new treatment strategies. The aim of this study was to assess the validity of GLUT1 expression as a prognostic biomarker and to elucidate to what extent it is immersed in poor clinical outcome among CRC patients.

PATIENTS AND METHODS

GLUT1 expression in peripheral blood specimens was analyzed by quantitative real-time polymerase chain reaction in 47 CRC patients and 20 healthy controls.

RESULTS

There was significantly elevated GLUT1 expression in peripheral blood of CRC patients than in controls (P < 0.001). The cutoff value of 0.605 provided 98% sensitivity and 100% specificity. There were significantly higher values of GLUT1 expression in patients under 50 years (P = 0.003), performance status 2 (P = 0.009), stage IV (P < 0.001), and presence of metastasis (P < 0.001). GLUT1 expression showed nonsignificant association with overall survival (P = 0.068), while tumor stage (P = 0.01) and metastasis (P = 0.009) were significantly associated with lower overall survival.

CONCLUSION

GLUT1 is sensitive and specific marker for CRC. It is overexpressed in young age patients, poor performance status, and stage IV patients. Although this was not statistically significant, GLUT 1 showed higher expression level in patients with lesser survival.

Expression of Glut-1 in Normal Endometrium and Endometrial Lesions: Analysis of 336 Cases

Background: Glucose transporter-1 (Glut-1) is a membrane glycoprotein that is, together with other glucose transporters, responsible for the regulation of glucose uptake. An increased expression of this protein seems to be a general feature of several malignant tumors that are able to reprogram their metabolism and switch from oxidative phosphorylation to aerobic glycolysis. Methods: We performed comprehensive immunohistochemical analysis of Glut-1 expression in 336 endometrial samples, including tumors, nontumor lesions, and normal tissues. Results: Expression of Glut-1 was found in 87% of endometrioid carcinomas (160/184 cases), 100% of serous carcinomas (29/29 cases), 100% of clear cell carcinomas (17/17 cases), 50% of polyps with atypical hyperplasia (8/16 cases), 12.5% of polyps with non-atypical hyperplasia (3/24 cases), 77% of hyperplasias with atypias (10/13 cases), 9% of hyperplasias without atypias (1/11 cases), 87% of secretory endometrium samples (13/15 cases), and in none of the nonsecretory endometrium samples (0/27 cases). In endometrioid carcinomas, Glut-1 was expressed in a marked geographical pattern. In nontumor lesions, its expression was more common in atypical hyperplasia and polyps with atypical hyperplasia compared with polyps with non-atypical hyperplasia and hyperplasias without atypia ( P = .00032). Conclusion: Our study confirms the high expression of Glut-1 not only in endometrioid carcinomas but also in other carcinomas of endometrium including clear cell and serous types. Glut-1 expression can be used as a surrogate marker in differential diagnosis between hyperplasia with and without atypia. Because of common Glut-1 expression in malignant tumors, therapeutic strategies influencing this protein or its signaling pathways can be beneficial.

Nanomedicine based curcumin and doxorubicin combination treatment of glioblastoma with scFv-targeted micelles: In vitro evaluation on 2D and 3D tumor models

NF-κB is strongly associated with poor prognosis of different cancer types and an important factor responsible for the malignant phenotype of glioblastoma. Overcoming chemotherapy-induced resistance caused by activation of PI3K/Akt and NF-κB pathways is crucial for successful glioblastoma therapy. We developed an all-in-one nanomedicine formulation for co-delivery of a chemotherapeutic agent (topoisomerase II inhibitor, doxorubicin) and a multidrug resistance modulator (NF-κB inhibitor, curcumin) for treatment of glioblastoma due to their synergism. Both agents were incorporated into PEG-PE-based polymeric micelles. The glucose transporter-1 (GLUT1) is overexpressed in many tumors including glioblastoma. The micellar system was decorated with GLUT1 antibody single chain fragment variable (scFv) as the ligand to promote blood brain barrier transport and glioblastoma targeting. The combination treatment was synergistic (combination index, CI of 0.73) against U87MG glioblastoma cells. This synergism was improved by micellar encapsulation (CI: 0.63) and further so with GLUT1 targeting (CI: 0.46). Compared to non-targeted micelles, GLUT1 scFv surface modification increased the association of micelles (>20%, P<0.01) and the nuclear localization of doxorubicin (∼3-fold) in U87MGcells, which also translated into enhanced cytotoxicity. The increased caspase 3/7 activation by targeted micelles indicates successful apoptosis enhancement by combinatory treatment. Moreover, GLUT1 targeted micelles resulted in deeper penetration into the 3D spheroid model. The increased efficacy of combination nanoformulations on the spheroids compared to a single agent loaded, or to non-targeted formulations, reinforces the rationale for selection of this combination and successful utilization of GLUT1 scFv as a targeting agent for glioblastoma treatment.

Facilitative glucose transporters: Implications for cancer detection, prognosis and treatment

It is long recognized that cancer cells display increased glucose uptake and metabolism. In a rate-limiting step for glucose metabolism, the glucose transporter (GLUT) proteins facilitate glucose uptake across the plasma membrane. Fourteen members of the GLUT protein family have been identified in humans. This review describes the major characteristics of each member of the GLUT family and highlights evidence of abnormal expression in tumors and cancer cells. The regulation of GLUTs by key proliferation and pro-survival pathways including the phosphatidylinositol 3-kinase (PI3K)-Akt, hypoxia-inducible factor-1 (HIF-1), Ras, c-Myc and p53 pathways is discussed. The clinical utility of GLUT expression in cancer has been recognized and evidence regarding the use of GLUTs as prognostic or predictive biomarkers is presented. GLUTs represent attractive targets for cancer therapy and this review summarizes recent studies in which GLUT1, GLUT3, GLUT5 and others are inhibited to decrease cancer growth.

Initial Standardized Uptake Value of Positron Emission Tomography Influences the Prognosis of Patients with Localized Gastric Adenocarcinoma Treated Preoperatively

BACKGROUND

In patients with localized gastric adenocarcinoma (LGAC) who receive preoperative therapy, tools to predict response or prognosticate outcome before therapy are lacking. We used initial standardized uptake value (iSUV) of positron emission tomography (PET) to evaluate its association with overall survival (OS).

METHODS

We identified 60 patients with confirmed LGAC who were treated with preoperative chemoradiation and had a baseline PET in addition to other routine staging. Fisher's exact test and Wilcoxon's rank sum test were used to determine the association between iSUV and other variables, and the log-rank test and Cox proportional hazards model were used for survival analysis.

RESULTS

The median iSUV was 6 (range, 0-28). The presence of signet ring cells in pretreatment biopsies correlated highly with low iSUV (≤ 6; p = 0.0017). Patients with a high iSUV (> 6) had a longer OS compared to those with a low iSUV (≤ 6; p = 0.0344). iSUV was not an independent predictor (p = 0.12); however, the risk of death was reduced for patients with an iSUV > 6 (hazard ratio = 0.26).

CONCLUSION

Our novel findings show that among LGAC patients treated with preoperative chemoradiation and surgery, those with a high iSUV have longer OS than patients with a low iSUV. iSUV appears to have a predictive role in patients with LGAC when treated with preoperative chemoradiation.

A comparative analysis of inhibitors of the glycolysis pathway in breast and ovarian cancer cell line models

Many cancer cells rely on aerobic glycolysis for energy production and targeting of this pathway is a potential strategy to inhibit cancer cell growth. In this study, inhibition of five glycolysis pathway molecules (GLUT1, HKII, PFKFB3, PDHK1 and LDH) using 9 inhibitors (Phloretin, Quercetin, STF31, WZB117, 3PO, 3-bromopyruvate, Dichloroacetate, Oxamic acid, NHI-1) was investigated in panels of breast and ovarian cancer cell line models. All compounds tested blocked glycolysis as indicated by increased extracellular glucose and decreased lactate production and also increased apoptosis. Sensitivity to several inhibitors correlated with the proliferation rate of the cell lines. Seven compounds had IC50 values that were associated with each other consistent with a shared mechanism of action. A synergistic interaction was revealed between STF31 and Oxamic acid when combined with the antidiabetic drug metformin. Sensitivity to glycolysis inhibition was also examined under a range of O2 levels (21% O2, 7% O2, 2% O2 and 0.5% O2) and greater resistance to the inhibitors was found at low oxygen conditions (7% O2, 2% O2 and 0.5% O2) relative to 21% O2 conditions. These results indicate growth of breast and ovarian cancer cell lines is dependent on all the targets examined in the glycolytic pathway with increased sensitivity to the inhibitors under normoxic conditions.

Additional Prognostic Value of SUVmax Measured by F-18 FDG PET/CT over Biological Marker Expressions in Surgically Resected Cervical Cancer Patients

PURPOSE

We compared the prognostic ability of the maximum standardized uptake value (SUVmax) and various biological marker expressions to predict recurrence in patients with surgically resected cervical cancer.

METHODS

A retrospective review identified 60 patients with cervical cancer who received [18F]fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) at the time of the diagnosis of cancer. The SUVmax, expressions of carbonic anhydrase-IX (CA-IX), glucose transporter 1 (GLUT-1), and vascular endothelial growth factor (VEGF), and known prognostic factors were investigated.

RESULTS

The median follow-up time was 22.2 months (range 3.4-43.1 months). Using univariate analyses, the stage (stage II, p = 0.0066), SUVmax (> 6, p = 0.027), parametrial involvement (p < 0.0001), and positivity for CA-IX (p = 0.0191) were associated with recurrences of cervical cancer. With the Cox proportional hazard regression model, the SUVmax was a potent predictor for disease-free survival (DFS).

CONCLUSION

Although CA-IX expression was related to DFS in the current study, the potent predictor for DFS was SUVmax. Therefore, SUVmax is of greater prognostic value than biological marker expression in patients with surgically resected cervical cancer.

Both GLUT-1 and GLUT-14 are Independent Prognostic Factors in Gastric Adenocarcinoma

BACKGROUND

The role of glucose transporter 14 (GLUT-14/SLC2A14) in tumor biology is entirely unknown, and the significance of hypoxia inducible factor 1-alpha (HIF1-α) for gastric adenocarcinoma is controversial. The impact of GLUT-1/SLC2A1 has never been confirmed in a Caucasian cohort.

METHODS

Between 1996 and 2007, 124 patients underwent gastrectomy for gastric adenocarcinoma. Tumor sections were incubated with GLUT-1, GLUT-14, and HIF1-α antibodies. Expression was analyzed for correlations with histopathology, marker coexpression, and patient survival by uni- and multivariate analyses.

RESULTS

Expressions of GLUT-1, GLUT-14, and HIF1-α were detectable in 50, 77.4, and 27.1 %, respectively. Expression of GLUT-1 was associated with pT-category (p = 0.019), pN-category (p = 0.019), tubular (WHO, p = 0.008), and intestinal (Lauren classification; p = 0.002) histologic subtypes. Expression of GLUT-14 was correlated with pT category (p = 0.043), whereas HIF1-α did not show any correlation with histopathology or survival. The median survival period was 14 months (95 % confidence interval [CI] 9.2-18.8 months) for GLUT-1-positive patients and 55 months (95 % CI 25.8-84.2; p = 0.01) for GLUT-1-negative patients. An inferior prognosis also was seen for GLUT-14-positive cases compared with GLUT-14-negative cases (p = 0.004). Thus, worst survival was seen with both GLUT-1- and GLUT-14-positive expression followed by single-positive and then double-negative cases (p = 0.004). In multivariate analysis including International Union Against Cancer (UICC) stages, R category, Lauren classification, surgery alone versus neoadjuvant/perioperative chemotherapy, and marker expression as covariates, GLUT-1 (p = 0.011) and GLUT-14 (p = 0.025) kept their prognostic independence.

CONCLUSIONS

The study findings suggest that detection of GLUT-1 and GLUT-14 is of high prognostic value. It gives additional information to UICC stages and identifies patients with inferior prognosis. If confirmed in prospective studies, these markers need to be considered for future classification systems.

Expression of glucose transporter protein 1 and p63 in serous ovarian tumor

AIM

It has been shown that glycolytic metabolism is increased in malignant cells. Cancer cell growth is an energy-related process supported by an increased glucose metabolism. In addition, p63, a known homolog of p53, is expressed predominantly in basal cell and squamous cell carcinomas. The purpose of this study was to evaluate the expression of glucose transporter protein 1 (GLUT1) and p63 in patients with serous ovarian tumor (benign, borderline and malignant) and study their close relationship with the malignant transformation of serous ovarian tumors.

METHODS

Two hundred formalin-fixed, paraffin-embedded sections were immunostained with rabbit anti-GLUT1 polyclonal antibody and mouse anti-p63 monoclonal antibody using the streptavidin-biotin method. The samples were as follows: 40 normal ovarian tissues, 40 serous cystadenomas, 40 borderline serous cystadenomas and 80 serous cystadenocarcinomas were stained.

RESULT

Normal ovarian tissues showed completely negative staining for GLUT1 and p63. However, from benign serious cystadenomas, borderline cystadenomas to cystadenocarcinomas, the expression of GLUT1 and p63 grew stronger (P < 0.05). Moreover, the intensity staining of GLUT1 maintained a significant association with the expression of p63 (P < 0.05). In χ²-test analysis, expression of borderline cystadenomas and cystadenocarcinomas, intraperitoneal implants, ascites, lymph node status and International Federation of Gynecology and Obstetrics (FIGO) stage and GLUT1 expression levels have an appalling significance (P < 0.05), while FIGO stage, intraperitoneal implants and lymph node status except patient age and ascites have a statistical significance with the expression of p63 levels (P < 0.05).

CONCLUSION

Our findings show a progressive increase in the expression of GLUT1 and p63 from the benign serous cystadenomas, borderline cystadenomas to cystadenocarcinomas. Overexpression of GLUT1 and p63 are associated with the histology FIGO stage and metastasis of the tumors. These data suggested that the expression of GLUT1 and p63 may be closely related to the malignant transformation of serous ovarian tumors. However, the relative importance of GLUT1 and p63 in ovarian serous tumor development and tumorigenesis remains mostly unclear and awaits further investigation.