Clinicopathological significance and linkage of the distribution of HIF-1alpha and GLUT-1 in human primary colorectal cancer

Arginine ADP-ribosyltransferase 1 Regulates Glycolysis in Colorectal Cancer via the PI3K/AKT/HIF1α Pathway

Objective

Arginine ADP-ribosyltransferase 1 (ART1) is involved in the regulation of a diverse array of pathophysiological processes, including proliferation, invasion, apoptosis, autophagy and angiogenesis of colorectal cancer (CRC) cells. However, how ART1 regulates glycolysis in CRC remains elusive.

Methods

To elucidate the role of ART1 in glycolysis in CRC, we assessed the protein level of ART1, hypoxia-inducible factor 1α (HIF1α), and glucose transporter type 1 (GLUT1) in 61 CRC tumor tissue specimens obtained from patients with different 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) uptake as analyzed by PET/CT before surgery. Colon adenocarcinoma CT26 cells with ART1 knockdown and overexpression were established, respectively, and the molecular mechanism underlying the effect of ART1 on glycolysis in CRC was determined both in vivo and in vitro.

Results

The expression of ART1 and GLUT1 was significantly associated with FDG uptake (P=0.037 and P=0.022, respectively) in CRC tissues. Furthermore, the expression of hexokinase 2 (HK2) and lactate dehydrogenase (LDH) was upregulated in ART1-overexpressed CT26 cells, but was downregulated in ART1-knockdown CT26 cells. The volume and weight of subcutaneously transplanted tumors were markedly increased in the ART1-overexpressed BALB/c mice group and decreased in the ART1-knockdown group. In CT26 cells, the overexpression of ART1 promoted the expression levels of HK2 and LDH, and knockdown of ART1 suppressed them in the CT26 tumors. In both normal and hypoxic conditions, ART1 expression was associated with the protein level of phospho-serine/threonine kinase (p-AKT), HIF1α, and GLUT1 but not with that of AKT in CT26 cells and subcutaneous transplanted tumors.

Conclusion

ART1 plays a crucial role in the elevation of glucose consumption in CT26 cells and may regulate GLUT1-dependent glycolysis in CRC via the PI3K/AKT/HIF1α pathway.

Immunohistochemical Analysis of the Metabolic Phenotype of Adrenal Cortical Carcinoma

Metabolic reprogramming is a cellular process contributing to carcinogenesis. However, it remains poorly understood in adrenal cortical carcinoma (ACC), an aggressive malignancy with overall poor prognosis and limited therapeutic options. We characterized the metabolic phenotype of ACC, by examining the immunoprofile of key proteins involved in glucose metabolism, hexokinase (HK1), pyruvate kinase (PKM1, PKM2), succinate dehydrogenase (SDHB), and phospho-S6 ribosomal protein (pS6), in a tissue microarray of 137 adrenal cortical tissue samples. Protein expression was compared between ACC (n = 42), adrenal cortical adenoma (ACA; n = 50), and normal adrenal cortical tissue samples (n = 45). Cytoplasmic expression of HK1 and PKM2 was significantly higher in ACC than in ACA (p < 0.001 and p = 0.014, respectively) or normal adrenal cortical tissue samples (p < 0.001 and p < 0.001, respectively). Expression of HK1 and PKM2 was also higher in ACA than in normal adrenal cortical tissue samples (p < 0.001 and p < 0.001, respectively). PKM1 expression was overall low in ACC, ACA, and normal samples, although expression of PKM1 was higher in ACC than in ACA (p = 0.027). There was no loss of cytoplasmic granular SDHB expression in our cohort of adrenal cortical tumors, and cytoplasmic expression of pS6 was lower in ACC than in ACA (p = 0.003) or normal adrenal cortical tissue samples (p = 0.008). Significantly, HK1 expression correlated with pyruvate kinase isoform (PKM2 and PKM1) expression (p < 0.001 and p = 0.007, respectively). Although functional validation was not performed, this study provides further evidence that metabolic reprogramming and altered glucose metabolism may occur in a subset of ACC through overexpression of intracellular glycolytic enzymes, notably HK1 and PKM2. The possibility of utilizing the reprogrammed glucose metabolism in ACC for novel therapeutic strategies should be explored in future studies.

The progress and development of GLUT1 inhibitors targeting cancer energy metabolism

A major difference between glucose metabolism in cancer cells and normal cells is that glucose in cancer cells is preferably converted to lactate in aerobic conditions rather than oxidized in mitochondria. This process is called aerobic glycolysis, known as the 'Warburg effect'. In this review, we focus on the energy-metabolism characteristics between tumor and normal cells, analyzing the regulation mechanism of energy metabolism based on glycolysis, and summarizing two targets on the upstream proteins of glycolysis, including glucose transporter (GLUT) and hexokinase. In addition, we proposed the risks and limitations of GLUT1-based drug research and summarized the current research progress of representative drugs, including natural and synthetic GLUT1 inhibitors. This will provide guidance for designing and synthesizing small molecule drugs targeting GLUT1 in glycolysis.

Biomarkers for Pancreatic Neuroendocrine Neoplasms (PanNENs) Management-An Updated Review

Pancreatic neuroendocrine tumors (PanNENs) are rare sporadic cancers or develop as part of hereditary syndromes. PanNENs can be both functioning and non-functioning based on whether they produce bioactive peptides. Some PanNENs are well differentiated while others-poorly. Symptoms, thus, depend on both oncological and hormonal causes. PanNEN diagnosis and treatment benefit from and in some instances are guided by biomarker monitoring. However, plasmatic monoanalytes are only suggestive of PanNEN pathological status and their positivity is typically followed by deepen diagnostic analyses through imaging techniques. There is a strong need for new biomarkers and follow-up modalities aimed to improve the outcome of PanNEN patients. Liquid biopsy follow-up, i.e., sequential analysis on tumor biomarkers in body fluids offers a great potential, that need to be substantiated by additional studies focusing on the specific markers and the timing of the analyses. This review provides the most updated panorama on PanNEN biomarkers.

Metabolic Heterogeneity of Cancer Cells: An Interplay between HIF-1, GLUTs, and AMPK

It has been long recognized that cancer cells reprogram their metabolism under hypoxia conditions due to a shift from oxidative phosphorylation (OXPHOS) to glycolysis in order to meet elevated requirements in energy and nutrients for proliferation, migration, and survival. However, data accumulated over recent years has increasingly provided evidence that cancer cells can revert from glycolysis to OXPHOS and maintain both reprogrammed and oxidative metabolism, even in the same tumor. This phenomenon, denoted as cancer cell metabolic plasticity or hybrid metabolism, depends on a tumor micro-environment that is highly heterogeneous and influenced by an intensity of vasculature and blood flow, oxygen concentration, and nutrient and energy supply, and requires regulatory interplay between multiple oncogenes, transcription factors, growth factors, and reactive oxygen species (ROS), among others. Hypoxia-inducible factor-1 (HIF-1) and AMP-activated protein kinase (AMPK) represent key modulators of a switch between reprogrammed and oxidative metabolism. The present review focuses on cross-talks between HIF-1, glucose transporters (GLUTs), and AMPK with other regulatory proteins including oncogenes such as c-Myc, p53, and KRAS; growth factor-initiated protein kinase B (PKB)/Akt, phosphatydyl-3-kinase (PI3K), and mTOR signaling pathways; and tumor suppressors such as liver kinase B1 (LKB1) and TSC1 in controlling cancer cell metabolism. The multiple switches between metabolic pathways can underlie chemo-resistance to conventional anti-cancer therapy and should be taken into account in choosing molecular targets to discover novel anti-cancer drugs.

Ligand-based design of GLUT inhibitors as potential antitumor agents

Glucose transporters (GLUTs) regulate glucose uptake and are often overexpressed in several human tumors. To identify new chemotypes targeting GLUT1, we built a pharmacophore model and searched against a NCI compound database. Sixteen hit molecules with good docking scores were screened for GLUT1 inhibition and antiproliferative activities. From these, we identified that compounds 2, 5, 6 and 13 inhibited the cell viability in a dose-dependent manner and that the IC₅₀s of 2 and 6 are<10 µM concentration in the HCT116 colon cancer cell line. Lead compound 13 (NSC295720) was a GLUT1 inhibitor. Docking studies show that GLUT1 residues Phe291, Phe379, Glu380, Trp388, and Trp412 were important for inhibitor binding.

Conformational Studies of Glucose Transporter 1 (GLUT1) as an Anticancer Drug Target

Glucose transporter 1 (GLUT1) is a facilitative glucose transporter overexpressed in various types of tumors; thus, it has been considered as an important target for cancer therapy. GLUT1 works through conformational switching from an outward-open (OOP) to an inward-open (IOP) conformation passing through an occluded conformation. It is critical to determine which conformation is preferred by bound ligands because the success of structure-based drug design depends on the appropriate starting conformation of the target protein. To find out the most favorable GLUT 1 conformation for ligand binding, we ran systemic molecular docking studies for different conformations of GLUT1 using known GLUT1 inhibitors. Our data revealed that the IOP is the preferred conformation and that residues Phe291, Phe379, Glu380, Trp388, and Trp412 may play critical roles in ligand binding to GLUT1. Our data suggests that conformational differences in these five amino acids in the different conformers of GLUT1 may be used to design ligands that inhibit GLUT1.

Obesity and gastrointestinal cancer: the interrelationship of adipose and tumour microenvironments

Increasing recognition of an association between obesity and many cancer types exists, but how the myriad of local and systemic effects of obesity affect key cellular and non-cellular processes within the tumour microenvironment (TME) relevant to carcinogenesis, tumour progression and response to therapies remains poorly understood. The TME is a complex cellular environment in which the tumour exists along with blood vessels, immune cells, fibroblasts, bone marrow-derived inflammatory cells, signalling molecules and the extracellular matrix. Obesity, in particular visceral obesity, might fuel the dysregulation of key pathways relevant to both the adipose microenvironment and the TME, which interact to promote carcinogenesis in at-risk epithelium. The tumour-promoting effects of obesity can occur at the local level as well as systemically via circulating inflammatory, growth factor and metabolic mediators associated with adipose tissue inflammation, as well as paracrine and autocrine effects. This Review explores key pathways linking visceral obesity and gastrointestinal cancer, including inflammation, hypoxia, altered stromal and immune cell function, energy metabolism and angiogenesis.

The Role of HIF-1alpha in Regional Lymph Nodes Metastasis in Colorectal Adenocarcinoma

Colorectal carcinoma has high morbidity and mortality rate worldwide, in which over 90% are adenocarcinoma. Colorectal carcinoma is one of the most cancer that metastasize to the lymph node. Angiogenesis have an important role in tumor growth and metastasis. Hypoxia is the trigger factor for angiogenesis. Hypoxia induced factor-1 (HIF-1) is one critical protein directly reacting to hypoxia. HIF-1alpha, a HIF-1 subunit, is an important regulator of angiogenesis. This study analyzed HIF-1a expression in colorectal adenocarcinoma with and without regional lymph node metastasis. This study was to prove that HIF-1a has a role in regional lymph node metastasis in colorectal adenocarcinoma. An analytical observational study was conducted on thirty formalin fixed paraffin-embedded colorectal adenocarcinoma tissues from Anatomic Pathology Laboratory of Dr. Soetomo Hospital. Detection of HIF-1alpha expressions were performed with immunohistochemistry method, using HIF-1alpha antibody. It were statistically analyzed using Mann-Whitney and Kruskal- Wallis methods. There were no significant differences in the expression of HIF-1alpha in colorectal adenocarcinoma with or without lymph node (LN) metastasis (p>0.05). As a conclusion, this study showed that HIF-1alpha has no role in LN metastasis in colorectal adenocarcinoma.

GLUT-1 overexpression as an unfavorable prognostic biomarker in patients with colorectal cancer

Background

Glucose transporter-1 (GLUT-1) exhibits altered expression in colorectal cancer (CRC). The aim of this study was to explore the association between GLUT-1 and survival conditions, as well as clinical features in CRC by meta-analysis.

Materials and Methods

Relevant studies were searched through predefined strategies, hazard ratios (HRs), odds ratios (ORs), and their 95% confidence intervals (CIs) were used as effective measures.

Results

A total of 14 studies with 2,077 patients were included in this meta-analysis. The results showed that GLUT-1 was not significantly associated with overall survival (OS) (HR=1.28, 95% CI=0.86–1.91, p=0.22) or disease-free survival (DFS) (HR=1.71, 95% CI=0.78–3.72, p=0.179). However, subgroup analysis indicated that GLUT-1 was a significant biomarker for poor DFS in rectal cancer (HR=2.47, 95% CI=1.21–5.05, p=0.013). GLUT-1 expression was also found to be significantly correlated with the presence of lymph node metastasis (n=8, OR=2.14, 95% CI=1.66–2.75, p<0.001), T stage (n=6, OR=1.73, 95% CI=1.17–2.58, p=0.007), higher Dukes stage (n=5, OR=2.92, 95% CI=2.16–3.95, p<0.001), female sex (n=4, OR=2.92, 95% CI=2.16–3.95, p<0.001), and presence of liver metastasis (n=3, OR=1.82, 95% CI=1.06–3.12, p=0.03).

Conclusion

In conclusion, this meta-analysis showed that GLUT-1 was associated with poor DFS in rectal cancer (RC). Furthermore, GLUT-1 was also an indicator of aggressive clinical features in CRC.

Evaluation of Hypoxia Inducible Factor-1α and Glucose Transporter-1 Expression in Non Melanoma Skin Cancer: An Immunohistochemical Study

INTRODUCTION

Hypoxia Inducible Factor-1 (HIF-1) is a mediator enabling cell adaptation to hypoxia. It plays its role mainly through transcription of many target genes including Glucose Transporter-1 (GLUT-1) gene.

AIM

The present work aimed at evaluating the pattern and distribution of HIF-1α and GLUT-1 in each case and control.

MATERIALS AND METHODS

A case-control and retrospective study was conducted on archival blocks diagnosed from pathology department as, Basal Cell Carcinoma (BCC, 20 cases), cutaneous Squamous Cell Carcinoma (SCC, 20 cases) and 20 normal site-matched skin biopsies from age and gender-matched healthy subjects as a control. Evaluation of both HIF-1α and GLUT1 expression using standard immunohistochemical techniques was performed on cut sections from selected paraffin embedded blocks.

RESULTS

HIF-1α was expressed in 90%, 35% and 100% of normal skin, BCC and SCC tumour islands respectively. It was up regulated in both BCC and SCC compared with normal skin (p= 0.001, p<0.001 respectively). GLUT-1 was expressed in 100%, 70% and 100% of normal skin, BCC and SCC tumour islands respectively. It was down regulated in Non Melanoma Skin Cancer (NMSC) cases compared with normal skin (p=0.004). HIF-1α and GLUT-1 localization in tumour nests was central, peripheral or central and peripheral. Both HIF-1α and GLUT-1 showed variable expression in stroma, adnexa and inflammatory cells. No significant correlation was found between Histo (H) score or expression percentage values of HIF-1α and those of GLUT-1 in tumour islands or in overlying epidermis either in BCC or SCC.

CONCLUSION

HIF-1α may have a role in NMSC pathogenesis through adaptation to hypoxia which results from excessive proliferation. GLUT-1 down regulation in NMSC may be explained by its consumption by proliferating tumour cells. The expression of HIF-1α and GLUT-1 in normal epidermis, stromal and adnexal structures needs further research.

Expression of glucose transporter-1 is correlated with hypoxia-inducible factor 1α and malignant potential in pancreatic neuroendocrine tumors

The present study aimed to investigate the prognostic usefulness of the expression of glucose transporter type 1 (GLUT-1) and GLUT-2, hypoxia-inducible factor 1α (HIF-1α) and insulin-like growth factor II messenger RNA-binding protein 3 (IMP3) in pancreatic neuroendocrine tumors (pNETs). Immunohistochemical staining for GLUT-1, GLUT-2, HIF-1α and IMP3 was performed in 70 pNET specimens. The expression of GLUT-1 and HIF-1α was significantly higher in the World Health Organization grade 2 (G2), neuroendocrine carcinoma cases and mixed-type pNETs compared with the G1 cases. Vessel invasion, a high Ki-67 labeling index and a high mitotic count were significantly more frequent in the GLUT-1- and HIF-1α-positive cases compared with the negative cases. Lymph node metastasis was significantly higher in the GLUT-1-positive cases than in the negative cases. Insulin expression was significantly higher in the IMP3-positive cases than the negative cases. The GLUT-1 expression group experienced a significantly poor disease-free survival rate compared with the negative GLUT-1 expression group. HIF-1α expression was significantly correlated with poor disease-free survival and overall survival rates. A multivariate analysis revealed that lymph node metastasis was an independent risk factor for disease-free survival in all cases. In the G1/G2 group, tumor size and lymph node metastasis were independent risk factors for disease-free survival. Overall, the results suggested that GLUT-1 is a useful prognostic biomarker for pNETs.

Identification and Optimization of the First Highly Selective GLUT1 Inhibitor BAY-876

Despite the long‐known fact that the facilitative glucose transporter GLUT1 is one of the key players safeguarding the increase in glucose consumption of many tumor entities even under conditions of normal oxygen supply (known as the Warburg effect), only few endeavors have been undertaken to find a GLUT1‐selective small‐molecule inhibitor. Because other transporters of the GLUT1 family are involved in crucial processes, these transporters should not be addressed by such an inhibitor. A high‐throughput screen against a library of ∼3 million compounds was performed to find a small molecule with this challenging potency and selectivity profile. The N‐(1H‐pyrazol‐4‐yl)quinoline‐4‐carboxamides were identified as an excellent starting point for further compound optimization. After extensive structure–activity relationship explorations, single‐digit nanomolar inhibitors with a selectivity factor of >100 against GLUT2, GLUT3, and GLUT4 were obtained. The most promising compound, BAY‐876 [N⁴‐[1‐(4‐cyanobenzyl)‐5‐methyl‐3‐(trifluoromethyl)‐1H‐pyrazol‐4‐yl]‐7‐fluoroquinoline‐2,4‐dicarboxamide], showed good metabolic stability in vitro and high oral bioavailability in vivo.

MUC16-mediated activation of mTOR and c-Myc reprograms pancreatic cancer metabolism

MUC16, a transmembrane mucin, facilitates pancreatic adenocarcinoma progression and metastasis. In the current studies, we observed that MUC16 knockdown pancreatic cancer cells exhibit reduced glucose uptake and lactate secretion along with reduced migration and invasion potential, which can be restored by supplementing the culture media with lactate, an end product of aerobic glycolysis. MUC16 knockdown leads to inhibition of mTOR activity and reduced expression of its downstream target c-MYC, a key player in cellular growth, proliferation and metabolism. Ectopic expression of c-MYC in MUC16 knockdown pancreatic cancer cells restores the altered cellular physiology. Our LC-MS/MS based metabolomics studies indicate global metabolic alterations in MUC16 knockdown pancreatic cancer cells, as compared to the controls. Specifically, glycolytic and nucleotide metabolite pools were significantly decreased. We observed similar metabolic alterations that correlated with MUC16 expression in primary tumor tissue specimens from human pancreatic adenocarcinoma cancer patients. Overall, our results demonstrate that MUC16 plays an important role in metabolic reprogramming of pancreatic cancer cells by increasing glycolysis and enhancing motility and invasiveness.

The recent progress of the mechanism and regulation of tumor necrosis in colorectal cancer

In colorectal cancer (CRC), despite the complex inducing and regulating mechanism in necrosis progress, the prognostic value of tumor necrosis has been reported. It is generally recognized that necrosis is associated with many process involving severe hypoxia, inflammatory responses and angiogenesis, all of which contribute to promote tumor growth and poor prognosis. In addition to local hypoxia, regulation by RIP kinase and the conversion from apoptosis to necrosis can result in necrosis also. Recent studies showed necrosis can be a histopathologic characteristic for special molecular phenotype of CRC. A novel and attractive complementary treatment, tumor necrosis therapy, using radiolabelled compounds avid for necrosis has emerged. However, the complicated regulatory mechanisms of tumor necrosis were rarely reported in CRC, and we collected and reviewed these effect and relevance in CRC.

An "imaging-biopsy" strategy for colorectal tumor reconfirmation by multipurpose paramagnetic quantum dots

Glucose transporter1 (Glut1) plays important roles in treatment of colorectal cancer (CRC) involving early-stage diagnosis, subtype, TNM stage, and therapeutic schedule. Currently, in situ marking and tracking of the tumor biomarkers via clinical imaging remains great challenges in early stage CRC diagnosis. In this study, we have developed a unique cell-targeted, paramagnetic-fluorescent double-signal molecular nanoprobe for CRC in vivo magnetic resonance imaging (MRI) diagnosis and subsequent biopsy. The unique molecular nanoprobe is composed of a fluorescent quantum dot (QD) core; a coating layer of paramagnetic DTPA-Gd coupled BSA ((Gd)DTPA∙BSA), and a surface targeting moiety of anti-Glut1 polyclonal antibody. The engineered (Gd)DTPA∙BSA@QDs-PcAb is 35 nm in diameter and colloidally stable under both basic and acidic conditions. It exhibits strong fluorescent intensities and high relaxivity (r1 and r2: 16.561 and 27.702 s(-1) per mM of Gd(3+)). Distribution and expression of Glut1 of CRC cells are investigated by in vitro cellular confocal fluorescent imaging and MR scanning upon treating with the (Gd)DTPA∙BSA@QDs-PcAb nanoprobes. In vivo MRI shows real-time imaging of CRC tumor on nude mice after intravenously injection of the (Gd)DTPA∙BSA@QDs-PcAb nanoprobes. Ex vivo biopsy is subsequently conducted for expression of Glut1 on tumor tissues. These nanoprobes are found biocompatible in vitro and in vivo. (Gd)DTPA∙BSA@QDs-PcAb targeted nanoprobe is shown to be a promising agent for CRC cancer in vivo MRI diagnosis and ex vivo biopsy analysis. The "imaging-biopsy" is a viable strategy for tumor reconfirmation with improved diagnostic accuracy and biopsy in personalized treatment.

Glucose-lactate metabolic cooperation in cancer: insights from a spatial mathematical model and implications for targeted therapy

A recent study has hypothesised a glucose-lactate metabolic symbiosis between adjacent hypoxic and oxygenated regions of a developing tumour, and proposed a treatment strategy to target this symbiosis. However, in vivo experimental support remains inconclusive. Here we develop a minimal spatial mathematical model of glucose-lactate metabolism to examine, in principle, whether metabolic symbiosis is plausible in human tumours, and to assess the potential impact of inhibiting it. We find that symbiosis is a robust feature of our model system-although on the length scale at which oxygen supply is diffusion-limited, its occurrence requires very high cellular metabolic activity-and that necrosis in the tumour core is reduced in the presence of symbiosis. Upon simulating therapeutic inhibition of lactate uptake, we predict that targeted treatment increases the extent of tissue oxygenation without increasing core necrosis. The oxygenation effect is correlated strongly with the extent of wild-type hypoxia and only weakly with wild-type symbiotic behaviour, and therefore may be promising for radiosensitisation of hypoxic, lactate-consuming tumours even if they do not exhibit a spatially well-defined symbiosis. Finally, we conduct in vitro experiments on the U87 glioblastoma cell line to facilitate preliminary speculation as to where highly malignant tumours might fall in our parameter space, and find that these experiments suggest a weakly symbiotic regime for U87 cells, thus raising the new question of what relationship might exist between symbiosis and tumour malignancy.

Expression and significance of hypoxia-inducible factor-1α and glucose transporter-1 in laryngeal carcinoma

Malignant cells show increased glucose uptake in vitro and in vivo. This process is considered to be mediated by glucose transporters (GLUTs). Hypoxia-inducible factor-1α (HIF-1α) may upregulate GLUT-1 expression. Little is known about the correlation between HIF-1α and GLUT-1 expression in laryngeal carcinoma. The current study investigated this correlation immunohistochemically, according to various clinical and pathological features, in 49 paraffin-embedded archival tissue blocks from patients with laryngeal squamous cell carcinoma. HIF-1α and GLUT-1 expression was detected in 63.3 (31/49) and 55.1% (27/49) of the tumour samples, respectively. HIF-1α expression was significantly correlated with lymph node classification (P=0.018), recurrence (P=0.02) and metastasis (P=0.031). GLUT-1A expression was significantly associated with recurrence (P=0.02) and metastasis (P=0.01). Univariate analyses revealed that HIF-1α (χ(2)=8.2; P=0.004) and GLUT-1 expression (χ(2)=9.0; P=0.003) were significantly associated with a poorer survival rate. In a multivariate analysis, GLUT-1 expression (P=0.006) was a significant predictor of poor survival rate, as well as the primary tumour site, lymph node invasion and distant metastasis. Based on Spearman's analysis, GLUT-1 expression and phosphatidylinositol 3-kinase (PI3K) expression were significantly correlated (r=0.504; P=0.000). This is the first study to demonstrate a significant correlation between GLUT-1 and HIF-1α expression in laryngeal carcinoma and to show increased GLUT-1 expression as an independent survival rate predictor. These results suggest that GLUT-1 is a potential new therapeutic target for laryngeal carcinoma.

Hypoxia-related proteins in patients with rectal cancer undergoing neoadjuvant combined modality therapy

BACKGROUND

We have previously demonstrated the prognostic significance of rectal cancer pathologic response to neoadjuvant chemoradiation. Recent studies in other cancers have reported that hypoxia influences response to neoadjuvant chemoradiation.

OBJECTIVE

This study aimed to 1) characterize hypoxia-related protein expression in locally advanced rectal cancer before neoadjuvant chemoradiation, 2) determine the comodulation of hypoxia-related protein expression, and 3) evaluate the relationship between hypoxia-related protein expression and overall survival, time to recurrence, and tumor regression grade.

DESIGN

Immunohistochemical analysis of 4 hypoxia-related proteins (HIF-1α, CA-IX, VEGF, and GLUT-1) was performed on archival pretreatment rectal cancer biopsies.

PATIENTS

: Eighty-five patients with locally advanced rectal cancer treated with neoadjuvant radiation and 5-fluorouracil-based chemotherapy were included.

MAIN OUTCOME MEASURES

The impact of hypoxia-related protein expression on outcome was evaluated by use of Cox proportional hazards model. Hypoxia-related protein expression was correlated with tumor regression grade by use of Spearman correlation coefficients.

RESULTS

Median follow-up was 54 months. CA-IX expression was associated with overall survival (p = 0.01). HIF-1α expression was weakly correlated with VEGF (r = 0.26, p = 0.02) and GLUT-1 (r = 0.35, p = 0.001). Hypoxia-related protein expression was not associated with time to recurrence or Mandard tumor regression grade.

CONCLUSIONS

Elevated CA-IX expression may be associated with poorer overall survival in locally advanced rectal cancer treated by neoadjuvant chemoradiation and resection. The expression of the hypoxia-related proteins HIF-1α, VEGF, and GLUT-1 may be comodulated in locally advanced rectal cancer. Further studies are needed to evaluate the mechanisms governing hypoxia regulation and the role of hypoxia in rectal cancer response to neoadjuvant chemoradiation.

Correlations between SUVmax and expression of GLUT1 and growth factors inducing lymphangiogenesis

RATIONALE AND OBJECTIVES

The purpose of this study was to assess the correlations between the maximum standardized uptake value (SUVmax) of colorectal carcinoma and hepatocyte growth factor (HGF), vascular endothelial growth factor C (VEGF-C), and their respective receptors using (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT).

METHODS

Fluorine-18-FDG PET/CT scans were performed on 33 patients with colorectal carcinoma before any treatment. The SUVmax of colorectal carcinoma and the clinicopathologic data associated with lymphatic metastases were analyzed. The expression of glucose transporter 1 (GLUT1), HGF, c-Met, VEGF-C, and vascular endothelial growth factor receptor 3 (VEGFR-3) in tumor tissues was analyzed using immunohistochemical methods. Lymphatic endothelial cells were marked with D2-40, and lymphatic vessel density (LVD) was recorded. The correlations were analyzed among the SUVmax of colorectal carcinoma, LVD, and the expression of GLUT1, HGF, c-Met, VEGF-C, and VEGFR-3 in tumor tissues.

RESULTS

SUVmax and LVD in 15 patients with lymphatic metastases were 13.00 ± 4.51 and 6.25 ± 1.54, respectively, whereas in 18 patients with nonmetastatic nodes, SUVmax and LVD were 9.66 ± 4.82 and 4.54 ± 1.02, respectively. The differences of SUVmax and LVD between metastatic and nonmetastatic patients were statistically significant (F = 4.153, P = .025, and F = 14.501, P = .001, respectively). There were no statistical differences of SUVmax and LVD in variably differentiated colorectal carcinoma (F = 0.708, P = .502, and F = 0.311, P = .735, respectively). The expression rates of GLUT1 in neoplastic and normal tissue were 72.7% (24 of 33) and 21.2% (seven of 33), respectively (P = .001). Moreover, the expression rates of GLUT1 in metastatic and nonmetastatic tissue were 93.33% (14 of 15) and 61.11% (11 of 18), respectively (P = .038). LVD and the integrated optical density of GLUT1 were 5.31 ± 1.53 and 8.21 × 10(4) ± 4.30 × 10(4), respectively, in tumor tissue, and there were linear correlations between SUVmax and LVD (r = 0.373, P = .033) and between SUVmax and expression of GLUT1 (r = 0.428, P = .013). The differences of SUVmax in HGF, c-Met, and VEGF-C groups with different expressions were statistically significant (P = .007, P = .009, and P = .030, respectively). No correlation was found between the expression of VEGFR-3 and SUVmax. The expression of GLUT1 and HGF as well as of GLUT1 and VEGF-C was rank correlated (r = 0.521, P = .002, and r = 0.505, P = .003, respectively). No rank correlations were found between the expression of GLUT1 and c-Met, GLUT1, and VEGFR-3.

CONCLUSIONS

The SUVmax of colorectal carcinoma was significantly higher in metastatic patients; the uptake of colorectal carcinoma was associated with LVD and the expression of HGF and VEGF-C but not with the expression of VEGFR-3.

Experimental study on the therapeutic effect of positron emission tomography agent [¹⁸F]-labeled 2-deoxy-2-fluoro-d-glucose in a colon cancer mouse model

The purpose of this study was to assess the therapeutic effect of positron emission tomography agent [¹⁸F]-labeled 2-deoxy-2-fluoro-d-glucose (¹⁸F-FDG) in a colorectal cancer mouse model. Three (3) tumor-bearing mice groups were treated with different doses of ¹⁸F-FDG. Mice were imaged by positron emission tomography with ¹⁸F-FDG before and after treatment weekly and the tumor growth rate was calculated. Tumor, brain, heart, and kidney of mice were analyzed for expression of glucose transporters and vascular endothelial growth factor (VEGF) by immunofluorescent staining, and the presence of apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) method. All 3 treated groups showed significant ¹⁸F-FDG reduction compared with the control group (p < 0.05). With higher treatment dose, better treatment response was observed. The tumor growth rate of all 3 treated groups was also significantly decreased after treatment (p < 0.05). Immunohistochemistry showed that tumors expressed more glucose transporters than in brain, heart, and kidney. The ¹⁸F-FDG treatment of mice resulted in apoptotic cell death in all 3 treated groups, which showed significant higher apoptotic cells than the control group (p < 0.05). The study suggests that ¹⁸F-FDG has a therapeutic effect in colonic cancer animal model, which indicates the potential for the development of positron therapy for colonic cancer and other cancers.

Comparison of beta-catenin with TGF-beta1, HIF-1alpha and patients' disease-free survival in human colorectal cancer

Beta-catenin accumulation is suppressed by TGF-beta1 (transforming growth factor beta1) in intestinal epithelium suggesting negative feedback between these two factors. Besides that, beta-catenin interacts with HIF-1alpha (hypoxia-inducible factor-1alpha) at the promoter region of HIF-1 target genes. Our study was aimed at comparison of beta-catenin with HIF-1alpha, TGF-beta1, Ki67 and survival of sporadic colorectal cancer patients. Expressions of beta-catenin, TGF-beta1, HIF-1alpha, Ki67 were evaluated in triads of specimens of each primary tumor of 72 sporadic colorectal cancers with immunohistochemistry due to limited availability of tissue material. Disease-free survival was analyzed in case of all 100 beta-catenin stained tumors, in 85 cancers stained for HIF-1 and in 72 neoplasms with TGFbeta1 staining. Beta-catenin, TGF-beta1 and HIF-1alpha accumulated in 72 colorectal cancer cells. Beta-catenin correlated both with HIF-1alpha and TGF-beta1 in all colorectal cancers (p < 0.009, r = 0.307 and p = 0.003, r = 0.342, respectively) and in subgroups of different clinico-pathological profile. Beta-catenin failed to correlate with Ki67. In case of beta-catenin, TGF-beta1 and HIF-1alpha, disease-free survival curves failed to show any statistically significant differences between groups of marker negative tumors, cancers with low expression and neoplasms with higher protein expression. Positive correlations between beta-catenin and TGF-beta1 may indicate ineffective attempts of TGF-beta1 to reduce intracellular level of beta-catenin in colorectal cancer. Associations between beta-catenin and HIF-1alpha reflect previously detected interactions between HIF-1alpha with beta-catenin and are confirmative for presence of such reactions in human colorectal cancer.

Relations of TGF-beta1 with HIF-1 alpha, GLUT-1 and longer survival of colorectal cancer patients

AIMS AND METHODS

During colorectal carcinogenesis, transforming growth factor beta 1 (TGF-beta1) undergoes a functional change from suppression of cancer cell proliferation to inhibition of T cell mediated anti-cancer immunity. We aimed to evaluate relations among TGF-beta1 and cancer cell survival factors hypoxia inducible factor-1 alpha (HIF-1 alpha) and glucose transporter 1 (GLUT-1) by immunohistochemistry in 108 colorectal cancers.

RESULTS

TGF-beta1 was detected in 87% (94/108), HIF-1 alpha in 85% (92/108), and GLUT-1 in 65% (70/108) of colorectal cancers. Not only did TGF-beta1 accumulate in cytoplasm of cancer cells but also there was strong immunoreactivity to TGF-beta1 in adjacent inflammatory cells. GLUT-1 was visualised in a membranous fashion while HIF-1 was expressed in a paranuclear pattern and occasionally in nuclei of malignant cells. Cancer immunoreactivities to TGF-beta1 correlated with HIF-1 alpha (p < 0.001, r = 0.516) and GLUT-1 (p < [corrected] 0.001, r = 0.355) in general and subgroups of different clinicopathological traits. TGF-beta1 expressions of inflammatory infiltrates correlated with longer patient survival (p = 0.05, r = 0.449) and immunoreactivities to HIF-1 alpha of cancer cells (p = 0.008, r = 0.254) particularly in node positive and deeply invading cancers but failed to associate significantly with GLUT-1.

CONCLUSIONS

HIF-1 alpha and GLUT-1 could cooperate with TGF-beta1, and TGF-beta1 might mediate cross-talk between the inflammatory environment and tumour with a favourable impact on patient survival.

Glucose transporter-1 in pulmonary neuroendocrine carcinomas: expression and survival analysis

Glucose transporter-1 (GLUT-1) mediates the transport of glucose across the cellular membrane. Its elevated levels and/or activation have been shown to be associated with malignancy. The aim of this study was to investigate GLUT-1 expression in pulmonary neuroendocrine carcinomas. Tissue microarray-based samples of 178 neuroendocrine carcinomas, including 48 typical carcinoids, 31 atypical carcinoids, 27 large cell neuroendocrine carcinomas and 72 small cell carcinomas from different patients, were studied immunohistochemically for GLUT-1 expression. Forty-seven percent (75/161) of pulmonary neuroendocrine carcinomas were immunoreactive with GLUT-1. GLUT-1 was observed in 7% (3/46) of typical carcinoid, 21% (6/29) of atypical carcinoid, 74% (17/23) of large cell neuroendocrine carcinoma and 78% (49/63) of small cell carcinoma. GLUT-1 expression correlated with increasing patient age (P=0.01) and with neuroendocrine differentiation/tumor type (P<0.001), but not with gender, tumor size or stage. GLUT-1 expression was seen in a characteristic membranous pattern of staining along the luminal borders or adjacent to necrotic areas. GLUT-1 expression was associated with an increased risk of death for neuroendocrine carcinomas as a group (risk ratio=2.519; 95% confidence interval=1.519-4.178; P<0.001) and carcinoids (risk ratio=4.262; 95% confidence interval=1.472-12.343; P=0.01). In conclusion, GLUT-1 is expressed in approximately half of the pulmonary neuroendocrine carcinomas and shows a strong correlation with neuroendocrine differentiation/grade, but not with other clinicopathologic variables. Further studies appear plausible to elucidate the prognostic significance of GLUT-1 expression in pulmonary carcinoids.

Hypoxia-inducible factor 1 alpha expression increases during colorectal carcinogenesis and tumor progression

BACKGROUND

Hypoxia-inducible factor 1 alpha (HIF-1alpha) is involved in processes promoting carcinogenesis of many tumors. However, its role in the development of colorectal cancer is unknown. To investigate the significance of HIF-1alpha during colorectal carcinogenesis and progression we examined its expression in precursor lesions constituting the conventional and serrated pathways, as well as in non-metastatic and metastatic adenocarcinomas.

METHODS

Immunohistochemistry and Western blot is used to analyse HIF-1alpha expression in normal colonic mucosa, hyperplastic polyps (HPP), sessile serrated adenomas (SSA), low-grade (TA-LGD) and high-grade (TA-HGD) traditional adenomas as well as in non-metastatic and metastatic colorectal adenocarcinomas. Eight colorectal carcinoma cell lines are tested for their HIF-1alpha inducibility after lipopolysaccharide (LPS) stimulation using western blot and immunocytochemistry.

RESULTS

In normal mucosa, HPP and TA-LGD HIF-1alpha was not expressed. In contast, perinuclear protein accumulation and nuclear expression of HIF-1alpha were shown in half of the examined SSA and TA-HGD. In all investigated colorectal carcinomas a significant nuclear HIF-1alpha overexpression compared to the premalignant lesions was observed but a significant correlation with the metastatic status was not found. Nuclear HIF-1alpha expression was strongly accumulated in perinecrotic regions. In these cases HIF-1alpha activation was seen in viable cohesive tumor epithelia surrounding necrosis and in dissociated tumor cells, which subsequently die. Enhanced distribution of HIF-1alpha was also seen in periinflammatory regions. In additional in vitro studies, treatment of diverse colorectal carcinoma cell lines with the potent pro-inflammatory factor lipopolysaccharide (LPS) led to HIF-1alpha expression and nuclear translocation.

CONCLUSION

We conclude that HIF-1alpha expression occurs in early stages of colorectal carcinogenesis and achieves a maximum in the invasive stage independent of the metastatic status. Perinecrotic activation of HIF-1alpha in invasive tumors underlines a dual role of HIF-1alpha by regulating both pro-survival and pro-death processes. HIF-1alpha up-regulation in response to LPS-mediated stimulation and periinflammatory expression in invasive carcinomas suggest its involvement in inflammatory events. These patterns of HIF-1alpha inducibility could contribute indirectly to the acquisition of a metastatic phenotype.

Immunohistochemical expression of the glucose transporters Glut-1 and Glut-3 in human malignant melanomas and benign melanocytic lesions

Background

Reported data indicate that cancer cells have increased rates of glucose metabolism, as determined by 18FDG-PET imaging in patients with malignancies. The results of many studies have demonstrated that the expression of glucose transporters, especially Glut-1, is increased in a variety of malignancies. This study was undertaken to assess the differential expression of Glut-1 and Glut-3 by benign and malignant melanocytic lesions.

Methods

Immunohistochemical staining for Glut-1 and Glut-3 was performed on paraffin-embedded tissue sections prepared from melanocytic nevi (12 cases), Spitz nevi (12 cases) and primary cutaneous malignant melanomas (20 cases).

Results

We observed immunoreactivity for Glut-1 in all melanocytic nevi, 9 of the 12 Spitz nevi and in 9 of the 20 malignant melanomas, whereas Glut-3 was expressed in all the melanocytic lesions, both benign and malignant.

Conclusion

These findings indicate that the glucose transporters Glut-1 and Glut-3 play a role in the glucose metabolism of melanocytic cells. Glut-1 was present in the majority of benign nevi, whereas its expression was downregulated in 55% of malignant melanomas. Our results suggest that glucose transporter Glut-1 expression can significantly discriminate between human malignant melanoma and benign melanocytic nevi, and support the idea that additional mechanisms other than Glut-1 may contribute to glucose uptake in melanomas.

High-fat, high-sucrose, and high-cholesterol diets accelerate tumor growth and metastasis in tumor-bearing mice

Epidemiological studies indicate that the risk factors for the development of various cancers are closely associated with metabolic symptoms such as obesity, hyperlipidemia, and insulin resistance caused by the excess consumption of high-calorie diets. However, the mechanisms of tumor growth and metastasis caused by feeding a high-calorie diet have not been clarified yet in tumor-bearing mice. In this study, we examined the effects of a high-fat (HF), a high-sucrose (HS), a high-cholesterol (HC) or a low-fat/low-sucrose (LF/LS) diet on tumor growth and metastasis in tumor-bearing mice. Angiogenic factors such as plasma leptin and monocyte chemoattractant protein-1 (MCP-1) were increased after the implantation of tumors, whereas conversely, an antiangiogenic factor, adiponectin, was reduced after the implantation of tumors in mice fed the HF, the HS, or the HC diet compared to LF/LS diet. Furthermore, we found that vascular endothelial growth factor, hypoxia inducible factor-1alpha and MCP-1 expression levels in tumors of mice fed the HF, the HS, or the HC diet were increased compared to those of mice fed the LF/LS diet. These findings suggest that the acceleration of tumor growth and metastasis by feeding the 3 diets may be due to the increase of angiogenic factors and the reduction of antiangiogenic factors.