Relation of hypoxia inducible factor 1 alpha and 2 alpha in operable non-small cell lung cancer to angiogenic/molecular profile of tumours and survival

Recapitulating epithelial tumor microenvironment in vitro using three dimensional tri-culture of human epithelial, endothelial, and mesenchymal cells

Background

Three-dimensional (3-D) cultures of cancer cells can potentially bridge the gap between 2-D drug screening and in vivo xenografts. The objective of this study was to characterize the cellular and extracellular matrix characteristics of spheroids composed of human lung epithelial cells (epi), pulmonary vascular endothelial (endo) cells, and human marrow-derived mesenchymal stems cells (MSCs).

Methods

Spheroids composed of epi/endo/MSCs, termed herein as synthetic tumor microenvironment mimics (STEMs), were prepared by the hanging drop method. Cellular composition and distribution in the STEMs was characterized using fluorescence microscopy. Induction of reactive oxygen species and upregulation of efflux transporters was quantified using fluorometry and PCR, respectively, and phenotypic markers were qualitatively assessed using immunohistochemistry.

Results

STEMs exhibited three unique characteristics not captured in other spheroid cultures namely, the presence of a spheroid core devoid of epithelial cells and primarily composed of MSCs, a small viable population of endothelial cells hypothesized to be closely associated with MSCs within the hypoxic core, and discrete regions with high expression for vimentin and cytokeratin-18, whose co-expression is co-related with enhanced metastasis. Although cells within STEMs show elevated levels of reactive oxygen species and mRNA for ABC-B1, an efflux transporter associated with drug resistance, they exhibited only modest resistance to paclitaxel and gemcitabine in comparison to 2-D tri-cultures.

Conclusions

The epi/endo/MSC spheroid model described herein offers a promising platform for understanding tumor biology and drug testing in vitro.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2634-1) contains supplementary material, which is available to authorized users.

Activation of Epidermal Growth Factor Receptor/p38/Hypoxia-inducible Factor-1α Is Pivotal for Angiogenesis and Tumorigenesis of Malignantly Transformed Cells Induced by Hexavalent Chromium

Hexavalent chromium (Cr(VI))-containing compounds are well established environmental carcinogens. Most mechanistic investigations of Cr(VI)-induced carcinogenesis focus on oxidative stress and various cellular responses, leading to malignant cell transformation or the first stage of metal-induced carcinogenesis. The development of malignantly transformed cells into tumors that require angiogenesis is the second stage. This study focuses on the second stage, in particular, the role of EGF receptor (EGFR) signaling in angiogenesis and tumorigenesis of Cr(VI)-transformed cells. Our preliminary studies have shown that EGFR is constitutively activated in Cr(VI)-transformed cells, in lung tissue from Cr(VI)-exposed animals, and in lung tumor tissue from a non-smoking worker occupationally exposed to Cr(VI) for 19 years. Using in vitro and in vivo models, the present study has investigated the role of EGFR in angiogenesis of Cr(VI)-transformed cells. The results show that Cr(VI)-transformed cells are angiogenic. Hypoxia-inducible factor-1α, pro-angiogenic protein matrix metalloproteinase 1, and VEGF are all highly expressed in Cr(VI)-transformed cells, in lung tissue from animals exposed to Cr(VI), and in lung tumor tissue from a non-smoking worker occupationally exposed to Cr(VI) for 19 years. p38 MAPK is also activated in Cr(VI)-transformed cells and in human lung tumor tissue. Inhibition of EGFR reduces p38 MAPK, resulting in decreased expression of hypoxia-inducible factor-1α, metalloproteinase 1, and VEGF, leading to suppressions of angiogenesis and tumorigenesis. Overall, the present study has demonstrated that EGFR plays an important role in angiogenesis and tumorigenesis of Cr(VI)-transformed cells.

Association of Hypoxia-Inducible Factor-2 Alpha Gene Polymorphisms with the Risk of Hepatitis B Virus-Related Liver Disease in Guangxi Chinese: A Case-Control Study

OBJECTIVE

Hypoxia-inducible factor-2 alpha (HIF-2a) plays a major role in the progression of disease, although the role of HIF-2α gene polymorphisms in hepatitis B virus (HBV)-related diseases remains elusive. The aim of this study is to determine whether HIF-2a rs13419896 and rs6715787 single-nucleotide polymorphisms (SNPs) are associated with susceptibility to chronic hepatitis B (CHB), liver cirrhosis (LC), or hepatocellular carcinoma (HCC).

METHOD

A case-control study of 107 patients with CHB, 83 patients with LC, 234 patients with HCC, and 224 healthy control subjects was carried out, and the HIF-2a rs13419896 and rs6715787 SNPs were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

No significant differences were observed in the genotype or allele frequency of two HIF-2a SNPs between the cases and controls (all p>0.05). However, in subgroup analysis by gender, the HIF-2a rs13419896 GA and AA genotypes were significantly associated with a risk of CHB (odds ratio [OR] = 3.565, 95% confidence interval [CI] = 1.123-11.314, p = 0.031 and OR = 12.506, 95% CI = 1.329-117.716, p = 0.027) in females, and the A allele of rs13419896 was associated with a risk of CHB (OR = 2.624, 95% CI = 1.244-5.537, p = 0.011) and LC (OR = 2.351, 95% CI = 1.002-5.518, p = 0.050) in females. The rs6715787 CG genotype polymorphism may contribute to a reduced risk of LC in the Guangxi Zhuang Chinese population (OR = 0.152, 95% CI = 0.028-0.807, p = 0.027), as determined via subgroup analysis by ethnicity. Moreover, binary logistic regression analyses that were adjusted by drinking status indicated that the AA genotype of rs13419896 may contribute to an increased risk of LC in the non-alcohol-drinking population (OR = 3.124, 95% CI = 1.091-8.947, p = 0.034). In haplotype analysis, GG haplotype was significantly associated with a reduced risk of LC (OR = 0.601, 95% CI = 0.419-0.862, p = 0.005).

CONCLUSIONS

The HIF-2a rs13419896 polymorphism is associated with an increased risk of CHB and LC in the Guangxi Chinese population, especially in females and in the non-alcohol-drinking population, while the HIF-2a gene rs6715787 polymorphism is associated with a decreased risk of LC in the Guangxi Zhuang population.

Clinicopathological and prognostic significance of hypoxia-inducible factor-1 alpha in lung cancer: a systematic review with meta-analysis

Hypoxia-inducible factor-1 alpha (HIF-1α) plays a vital role in the initiation, evaluation and prognosis in lung cancer. The prognostic value of HIF-1α reported in diverse study remains disputable. Accordingly, a meta-analysis was implemented to further understand the prognostic role of HIF-1α in lung cancer. The relationship between HIF-1α and the clinicopathological characteristics and prognosis of lung cancer were investigated by a meta-analysis. PubMed and Embase were searched from their inception to January 2015 for observational studies. Fixed-effects or random-effects meta-analyses were used to calculate odds ratios and 95% confidence intervals of different comparisons. A total of 20 studies met the criteria. The results showed that HIF-1α expression in lung cancer tissues was significantly higher than that in normal lung tissues. Expression of HIF-1α in patients with squamous cell carcinoma was significantly higher than that of patients with adenocarcinomas. Similarly, non-small cell lung cancer (NSCLC) patients had higher HIF-1α expression than small cell lung cancer (SCLC) patients. Moreover, lymph node metastasized tissues had higher HIF-1α expression than non-lymph node metastasized tissues. A high level HIF-1α expression was well correlated with the expression of vascular endothelial growth factor and epidermal growth factor receptor in the NSCLC. Notably, NSCLC or SCLC patients with positive HIF-1α expression in tumor tissues had lower overall survival rate than patients with negative HIF-1α expression. It was suggested that HIF-1α expression may be a prognostic biomarker and a potential therapeutic target for lung cancer.

Regional Emphysema of a Non-Small Cell Tumor Is Associated with Larger Tumors and Decreased Survival Rates

RATIONALE

Chronic obstructive pulmonary disease is associated with a worse overall survival in non-small cell lung cancer. Lung emphysema is one component of chronic obstructive pulmonary disease. We hypothesized that emphysema of the tumor region may result in larger tumors and a poorer overall survival.

METHODS

We evaluated 304 cases of non-small cell lung cancer from a prospectively enrolled cohort. The lung was divided into equal volumetric thirds (upper, middle, or lower region). Emphysema was defined as percentage of low-attenuation areas less than -950 Hounsfield units (%LAA-950) and measured for each region. Whole-lung %LAA-950 was defined as the emphysema score of the entire lung parenchyma, whereas regional %LAA-950 was the score within that particular region (upper, middle, or lower). The emphysema score of the region in which the tumor occurred was defined as the tumor %LAA-950. Tumor diameter was measured while blinded to characteristics of the lung parenchyma. A proportional hazards model was used to control for multiple factors associated with survival.

MEASUREMENTS AND MAIN RESULTS

Increasing tumor %LAA-950 was associated with larger tumors (P = 0.024). Survival, stratified by stage, was significantly worse in those with tumor %LAA-950 greater than or equal to the 50th percentile versus less than the 50th percentile (P = 0.046). Whole-lung %LAA-950 and regional %LAA-950 (e.g., regional emphysema without tumor occurring in the region) were not significantly associated with survival. There were no differences in presenting symptoms or locations of mediastinal or distant metastasis by emphysema score. Increasing tumor %LAA-950 was associated with an increased risk of death (adjusted hazard ratio, 1.36; confidence interval, 1.09-1.68; P = 0.006) after adjustment for age, sex, smoking status, histology, stage, performance status, chemotherapy, radiation, and surgery. Sensitivity analyses revealed no significant difference in the effect size or test of significance for each of the following conditions: (1) exclusion of cases with central tumor location, (2) exclusion of cases where surgery was performed, (3) exclusion of cases where radiation therapy was performed, (4) exclusion of cases where epidermal growth factor receptor tyrosine kinase inhibitors were administered, and (5) inclusion of only stage IV disease.

CONCLUSIONS

Increasing emphysema of the region in which a non-small cell lung cancer tumor occurs is associated with increasing tumor size and worse overall survival.

Potential Role of Epigenetic Mechanism in Manganese Induced Neurotoxicity

Manganese is a vital nutrient and is maintained at an optimal level (2.5–5 mg/day) in human body. Chronic exposure to manganese is associated with neurotoxicity and correlated with the development of various neurological disorders such as Parkinson's disease. Oxidative stress mediated apoptotic cell death has been well established mechanism in manganese induced toxicity. Oxidative stress has a potential to alter the epigenetic mechanism of gene regulation. Epigenetic insight of manganese neurotoxicity in context of its correlation with the development of parkinsonism is poorly understood. Parkinson's disease is characterized by the α-synuclein aggregation in the form of Lewy bodies in neuronal cells. Recent findings illustrate that manganese can cause overexpression of α-synuclein. α-Synuclein acts epigenetically via interaction with histone proteins in regulating apoptosis. α-Synuclein also causes global DNA hypomethylation through sequestration of DNA methyltransferase in cytoplasm. An individual genetic difference may also have an influence on epigenetic susceptibility to manganese neurotoxicity and the development of Parkinson's disease. This review presents the current state of findings in relation to role of epigenetic mechanism in manganese induced neurotoxicity, with a special emphasis on the development of Parkinson's disease.

HIF-1α and GLUT-1 Expression in Atypical Endometrial Hyperplasia, Type I and II Endometrial Carcinoma: A Potential Role in Pathogenesis

INTRODUCTION

Hypoxia-Inducible Factor 1α (HIF-1α) is one of the major adaptive responses to hypoxia, regulating the activity of glucose transporter -1 (GLUT-1), responsible for glucose uptake.

AIM

To evaluate the immunohistochemical expression of both HIF-1α and GLUT-1 in type I and II endometrial carcinoma and their correlation with the available clinicopathologic variables in each type.

MATERIALS AND METHODS

A retrospective study was conducted on archival blocks diagnosed from pathology department between April 2010 and August 2014 included 9 cases of atypical hyperplasia and 67 cases of endometrial carcinoma. Evaluation of both HIF-1α and GLUT-1 expression using standard immunohistochemical techniques performed on cut sections from selected paraffin embedded blocks.

STATISTICAL ANALYSIS

Descriptive analysis of the variables and statistical significances were calculated by non-parametric chi-square test using the Statistical Package for the Social Sciences version 12.0 (SPSS).

RESULTS

HIF-1α was expressed in epithelial (88.9%, 52.2%, 61.2% and 50%) and stromal (33.3%, 74.6%. 71.4% and 83.3%) components of hyperplasia, total cases of EC, type I and II EC, respectively. GLUT-1 was expressed in the epithelial component of 88.9%, 98.5%, 98% and 100% of hyperplasia, total EC cases, type I and II EC, respectively. The necrosis related pattern of epithelial HIF-1α expression was in favour of type II (p=0.018) and grade III (p=0.038). HIF-1α H-score was associated with high apoptosis in both type I and total cases of EC (p=0.04). GLUT-1 H-score was negatively correlated with apoptotic count (p=0.04) and associated with high grade (p=0.003) and advanced stage in total EC (p=0.004). GLUT-1 H-score was correlated with the pattern of HIF-1α staining in all cases of EC (p= 0.04).

CONCLUSION

The role of HIF-1α in epithelial cells may differ from that of stromal cells in EC; however they augment the expression of each other supporting the crosstalk between them. The stepwise increase in H- score of GLUT-1 in the studied cases implies its potential role in carcinogenesis of EC. HIF-1α may promote GLUT-1 expression in EC especially surrounding areas of necrosis. The differences between type I and type II EC regarding HIF-1α and GLUT-1 expression may confirm the differences in their aetiopathogenesis.

Therapeutic targeting of hypoxia and hypoxia-inducible factors in cancer

Insufficient tissue oxygenation, or hypoxia, contributes to tumor aggressiveness and has a profound impact on clinical outcomes in cancer patients. At decreased oxygen tensions, hypoxia-inducible factors (HIFs) 1 and 2 are stabilized and mediate a hypoxic response, primarily by acting as transcription factors. HIFs exert differential effects on tumor growth and affect important cancer hallmarks including cell proliferation, apoptosis, differentiation, vascularization/angiogenesis, genetic instability, tumor metabolism, tumor immune responses, and invasion and metastasis. As a consequence, HIFs mediate resistance to chemo- and radiotherapy and are associated with poor prognosis in cancer patients. Intriguingly, perivascular tumor cells can also express HIF-2α, thereby forming a "pseudohypoxic" phenotype that further contributes to tumor aggressiveness. Therefore, therapeutic targeting of HIFs in cancer has the potential to improve treatment efficacy. Different strategies to target hypoxic cancer cells and/or HIFs include hypoxia-activated prodrugs and inhibition of HIF dimerization, mRNA or protein expression, DNA binding capacity, and transcriptional activity. Here we review the functions of HIFs in the progression and treatment of malignant solid tumors. We also highlight how HIFs may be targeted to improve the management of patients with therapy-resistant and metastatic cancer.

Hypoxia and Hypoxia-Inducible Factors in Leukemias

Despite huge improvements in the treatment of leukemia, the percentage of patients suffering relapse still remains significant. Relapse most often results from a small number of leukemic stem cells (LSCs) within the bone marrow, which are able to self-renew, and therefore reestablish the full tumor. The marrow microenvironment contributes considerably in supporting the protection and development of leukemic cells. LSCs share specific niches with normal hematopoietic stem cells with the niche itself being composed of a variety of cell types, including mesenchymal stem/stromal cells, bone cells, immune cells, neuronal cells, and vascular cells. A hallmark of the hematopoietic niche is low oxygen partial pressure, indeed this hypoxia is necessary for the long-term maintenance of hematopoietic stem/progenitor cells. Hypoxia is a strong signal, principally maintained by members of the hypoxia-inducible factor (HIF) family. In solid tumors, it has been well established that hypoxia triggers intrinsic metabolic changes and microenvironmental modifications, such as the stimulation of angiogenesis, through activation of HIFs. As leukemia is not considered a “solid” tumor, the role of oxygen in the disease was presumed to be inconsequential and remained long overlooked. This view has now been revised since hypoxia has been shown to influence leukemic cell proliferation, differentiation, and resistance to chemotherapy. However, the role of HIF proteins remains controversial with HIFs being considered as either oncogenes or tumor suppressor genes, depending on the study and model. The purpose of this review is to highlight our knowledge of hypoxia and HIFs in leukemic development and therapeutic resistance and to discuss the recent hypoxia-based strategies proposed to eradicate leukemias.

Hypoxia inducible factor-1 mediates upregulation of urokinase-type plasminogen activator receptor gene transcription during hypoxia in cervical cancer cells

Hypoxia occurs during development of cervical cancer and is considered to correlate with its invasion. Hypoxia mediates tumor cells to have more invasive property in a variety of cancers. Urokinase plasminogen activator receptor (uPAR) which mediates invasion is considered to be induced by hypoxia. We sought to determine the regulators of uPAR expression during hypoxia in cervical cancer. We showed that cervical cancer cell lines, CaSki and CA, were more invasive under hypoxic condition (1% O2) than under normoxic condition (20% O2) by invasion assays. Using western blot analysis, hypoxia enhanced the endogenous hypoxia-inducible factor (HIF)-1α and uPAR protein expression. uPAR mRNA level was also upregulated by hypoxia using real-time RT-PCR. Overexpression of HIF-1α which is induced by hypoxia activated the transcriptional activity of the uPAR promoter by luciferase assays. HIF-1 protein bound the putative HIF-1 response element on the uPAR promoter using electrophoretic mobility shift analysis, and additional luciferase assays show that this is essential for uPAR transactivation by HIF-1. HIF-1 overexpression enhanced the endogenous uPAR expression and introduction of siRNA for HIF-1α diminishes uPAR expression during hypoxia. These results indicate the upregulation of uPAR by hypoxia in cervical cancer cells is mediated through HIF-1. In cervical cancer tissues, we also demonstrated that uPAR protein expression was detected in cervical cancer but not in normal cervix or cervical intraepithelial neoplasia (CIN) by immunohistopathological staining. Our results provide evidence that regulation of uPAR expression by HIF-1 represents a mechanism for cervical cancer invasion during hypoxia.

SENP1 desensitizes hypoxic ovarian cancer cells to cisplatin by up-regulating HIF-1α

Hypoxia-inducible factor 1 alpha (HIF-1α) is closely related to chemoresistance of ovarian cancers. Although it is reported that HIF-1α can be regulated by Sentrin/SUMO-specific protease 1 (SENP1), the effects of SENP1 on HIF-1α is still controversial. In this study, we identified that SENP1 positively regulated the expression of HIF-1α by deSUMOylation and weakened the sensitivity of hypoxic ovarian cancer cells to cisplatin. These results indicate that SENP1 is a positive regulator of HIF-1α and plays a negative role in ovarian cancer chemotherapy.

HIF-2α regulates CDCP1 to promote PKCδ-mediated migration in hepatocellular carcinoma

Overexpression of CUB domain-containing protein 1 (CDCP1), a transmembrane glycoprotein and major substrate of Src family kinases (SFKs), always indicates unfavorable outcomes in various cancers. The characteristics of CDCP1 in hepatocellular carcinoma (HCC) have not been assessed. Most recently, CDCP1 was identified as a specific target gene of HIF-2α in clear cell renal carcinoma (CC-RCC). However, considering the role of HIF-2α in the progression of HCC is highly controversial, it is necessary to figure out whether HIF-2α and CDCP1 play a significant part in the metastasis of HCC. Our results showed that HIF-2α and CDCP1 were both induced by hypoxia, and the activation of CDCP1 was HIF-2α dependent. CDCP1 was governed by HIF-2α at mRNA and protein levels in HCC cell lines. Moreover, knocking down of HIF-2α not only inhibited cell invasion but also impaired the expression of Tyr(311) phosphorylation of protein kinase Cδ (PKCδ) which is a downstream factor of CDCP1 and has been reported to induce malignant migration in various tumors. Analysis of human HCC samples showed a negative correlation of CDCP1 expression with disease-free survival, and CDCP1 was an independent prognostic factors of disease-free survival. Taken together, these data demonstrated that HIF-2α could promote HCC cell migration by regulating CDCP1, and targeting HIF-2α-CDCP1-PKCδ pathway might be effective to inhibit HCC metastasis.

Targeting Hypoxia-Inducible Factor 1α in a New Orthotopic Model of Glioblastoma Recapitulating the Hypoxic Tumor Microenvironment

Tissue hypoxia and necrosis represent pathophysiologic and histologic hallmarks of glioblastoma (GBM). Although hypoxia inducible factor 1α (HIF-1α) plays crucial roles in the malignant phenotypes of GBM, developing HIF-1α-targeted agents has been hampered by the lack of a suitable preclinical model that recapitulates the complex biology of clinical GBM. We present a new GBM model, MGG123, which was established from a recurrent human GBM. Orthotopic xenografting of stem-like MGG123 cells reproducibly generated lethal tumors that were characterized by foci of palisading necrosis, hypervascularity, and robust stem cell marker expression. Perinecrotic neoplastic cells distinctively express HIF-1α and are proliferative in both xenografts and the patient tissue. The xenografts contain scattered hypoxic foci that were consistently greater than 50 μm distant from blood vessels, indicating intratumoral heterogeneity of oxygenation. Hypoxia enhanced HIF-1α expression in cultured MGG123 cells, which was abrogated by the HIF-1α inhibitors digoxin or ouabain. In vivo, treatment of orthotopic MGG123 xenografts with digoxin decreased HIF-1α expression, vascular endothelial growth factor mRNA levels, and CD34-positive vasculature within the tumors, and extended survival of mice bearing the aggressive MGG123 GBM. This preclinical tumor model faithfully recapitulates the GBM-relevant hypoxic microenvironment and stemness and is a suitable platform for studying disease biology and developing hypoxia-targeted agents.

The A Allele at rs13419896 of EPAS1 Is Associated with Enhanced Expression and Poor Prognosis for Non-Small Cell Lung Cancer

Hypoxia-inducible factor-2α (HIF-2α, or EPAS1) is important for cancer progression, and is a putative biomarker for poor prognosis for non-small cell lung cancer (NSCLC). However, molecular mechanisms underlying the EPAS1 overexpression are not still fully understood. We explored a role of a single nucleotide polymorphism (SNP), rs13419896 located within intron 1 of the EPAS1 gene in regulation of its expression. Bioinformatic analyses suggested that a region including the rs13419896 SNP plays a role in regulation of the EPAS1 gene expression and the SNP alters the binding activity of transcription factors. In vitro analyses demonstrated that a fragment containing the SNP locus function as a regulatory region and that a fragment with A allele showed higher transactivation activity than one with G, especially in the presence of overexpressed c-Fos or c-Jun. Moreover, NSCLC patients with the A allele showed poorer prognosis than those with G at the SNP even after adjustment with various variables. In conclusion, the genetic polymorphism of the EPAS1 gene may lead to variation of its gene expression levels to drive progression of the cancer and serve as a prognostic marker for NSCLC.

Epimutagenesis: A prospective mechanism to remediate arsenic-induced toxicity

Arsenic toxicity is a global issue, addressed by the World Health Organization as one of the major natural calamities faced by humans. More than 137 million individuals in 70 nations are affected by arsenic mainly through drinking water and also through diet. Chronic arsenic exposure leads to various types of patho-physiological end points in humans including cancers. Arsenic, a xenobiotic substance, is biotransformed in the body to its methylated species by using the physiological S-adenosyl methionine (SAM). SAM dictates methylation status of the genome and arsenic metabolism leads to depletion of SAM leading to an epigenetic disequilibrium. Since epigenetics is one of the major phenomenon at the interface between the environment and human health impact, its disequilibrium by arsenic inflicts upon the chromatin compaction, gene expression, genomic stability and a host of biomolecular interactions, the interactome within the cell. Since arsenic is not mutagenic but is carcinogenic in nature, arsenic induced epimutagenesis has come to the forefront since it determines the transcriptional and genomic integrity of the cell. Arsenic toxicity brings forth several pathophysiological manifestations like dermatological non-cancerous, pre-cancerous and cancerous lesions, peripheral neuropathy, DNA damage, respiratory disorders and cancers of several internal organs. Recently, several diseases of similar manifestations have been explained with the relevant epigenetic perspectives regarding the possible molecular mechanism for their onset. Hence, in the current review, we comprehensively try to intercalate the information on arsenic-induced epigenetic alterations of DNA, histones and microRNA so as to understand whether the arsenic-induced toxic manifestations are brought about by the epigenetic changes. We highlight the need to understand the aspect of epimutagenesis and subsequent alterations in the cellular interactome due to arsenic-induced molecular changes, which may be utilized to develop putative therapeutic strategies targeting both oxidative potential and epimutagenesis in humans.

Differential regulation of HIF-1α and HIF-2α in neuroblastoma: Estrogen-related receptor alpha (ERRα) regulates HIF2A transcription and correlates to poor outcome

Hypoxia-inducible factors (HIFs) are differentially regulated in tumor cells. While the current paradigm supports post-translational regulation of the HIF-α subunits, we recently showed that hypoxic HIF-2α is also transcriptionally regulated via insulin-like growth factor (IGF)-II in the childhood tumor neuroblastoma. Here, we demonstrate that transcriptional regulation of HIF-2α seems to be restricted to neural cell-derived tumors, while HIF-1α is canonically regulated at the post-translational level uniformly across different tumor forms. Enhanced expression of HIF2A mRNA at hypoxia is due to de novo transcription rather than increased mRNA stability, and chemical stabilization of the HIF-α proteins at oxygen-rich conditions unexpectedly leads to increased HIF2A transcription. The enhanced HIF2A levels do not seem to be dependent on active HIF-1. Using a transcriptome array approach, we identified members of the Peroxisome proliferator-activated receptor gamma coactivator (PGC)/Estrogen-related receptor (ERR) complex families as potential regulators of HIF2A. Knockdown or inhibition of one of the members, ERRα, leads to decreased expression of HIF2A, and high expression of the ERRα gene ESRRA correlates with poor overall and progression-free survival in a clinical neuroblastoma material consisting of 88 tumors. Thus, targeting of ERRα and pathways regulating transcriptional HIF-2α are promising therapeutic avenues in neuroblastoma.

β-Caryophyllene potently inhibits solid tumor growth and lymph node metastasis of B16F10 melanoma cells in high-fat diet-induced obese C57BL/6N mice

We reported previously that high-fat diet (HFD) feeding stimulated solid tumor growth and lymph node (LN) metastasis in C57BL/6N mice injected with B16F10 melanoma cells. β-caryophyllene (BCP) is a natural bicyclic sesquiterpene found in many essential oils and has been shown to exert anti-inflammatory activities. To examine whether BCP inhibits HFD-induced melanoma progression, 4-weeks old, male C57BL/6N mice were fed a control diet (CD, 10 kcal% fat) or HFD (60 kcal% fat + 0, 0.15 or 0.3% BCP) for the entire experimental period. After 16 weeks of feeding, B16F10s were subcutaneously injected into mice. Three weeks later, tumors were resected, and mice were killed 2 weeks post-resection. Although HFD feeding increased body weight gain, fasting blood glucose levels, solid tumor growth, LN metastasis, tumor cell proliferation, angiogenesis and lymphangiogenesis, it decreased apoptotic cells, all of which were suppressed by dietary BCP. HFD feeding increased the number of lipid vacuoles and F4/80+ macrophage (MΦ) and macrophage mannose receptor (MMR)+ M2-MΦs in tumor tissues and adipose tissues surrounding the LN, which was suppressed by BCP. HFD feeding increased the levels of CCL19 and CCL21 in the LN and the expression of CCR7 in the tumor; these changes were blocked by dietary BCP. In vitro culture results revealed that BCP inhibited lipid accumulation in 3T3-L1 preadipocytes; monocyte migration and monocyte chemoattractant protein-1 secretion by B16F10s, adipocytes and M2-MΦs; angiogenesis and lymphangiogenesis. The suppression of adipocyte and M2-cell accumulation and the inhibition of CCL19/21-CCR7 axis may be a part of mechanisms for the BCP suppression of HFD-stimulated melanoma progression.

Clinical implications of serum hypoxia inducible factor-1α and vascular endothelial growth factor in lung cancer

AIMS AND BACKGROUND

Hypoxia inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) have been deemed as key in angiogenesis of lung cancer. The aim of this study was to investigate diagnostic and prognostic values of HIF-1α and VEGF in patients with lung cancer.

METHODS

From May 1, 2011, to April 20, 2014, blood samples and/or pleural effusions were collected from 100 patients with lung cancer, 18 patients with tuberculosis, 47 patients with community-acquired pneumonia, and 29 healthy controls. The pretreatment levels of HIF-1α and VEGF were measured by enzyme-linked immunoassays. Patients with lung cancer were followed up during the period of this study and survival times were recorded for analysis.

RESULTS

We detected that the levels of serum and pleural HIF-1α in lung cancer were significantly higher than those in the tuberculosis population, and that the VEGF expressions were not significantly different between malignancy and benign diseases. An area under the curve of pleural HIF-1α (0.877 ± 0.053) showed a high ability to differentiate lung cancer from benign diseases. The significant negative predictors of survival in the univariate analysis were performance status (gt;1), no anticancer therapy, low serum albumin, advanced stage, and serum high level of VEGF (gt;324.17 pg/mL), while in the multivariate Cox regression analysis, only the pretreatment serum level of VEGF, stage, and anticancer therapy were identified as independent prognostic factors.

CONCLUSIONS

The overexpression of HIF-1α especially in pleural effusion may be an angiogenic factor for distinguishing malignancy from tuberculosis, and the pretreatment level of serum VEGF may be an independent predictor of survival.

Methyl 3-((6-methoxy-1,4-dihydroindeno[1,2-c]pyrazol-3-yl)amino)benzoate (GN39482) as a tubulin polymerization inhibitor identified by MorphoBase and ChemProteoBase profiling methods

A series of indenopyrazoles was synthesized from the corresponding indanones and phenyl isothiocyanates in two steps. Among the compounds synthesized, methyl 3-((6-methoxy-1,4-dihydroindeno[1,2-c]pyrazol-3-yl)amino)benzoate 6m (GN39482) was found to possess a promising antiproliferative activity toward human cancer cells without affecting any antimicrobial and antimalarial activities at 100 nM. Both a methoxy group at R(1) position and a methoxycarbonyl group at R(2) position of the anilinoquinazoline framework are essential for the high cell growth inhibition. Both MorphoBase and ChemProteoBase profiling analyses suggested that compound 6m was classified as a tubulin inhibitor. Indeed, compound 6m inhibited the acetylated tubulin accumulation and the microtubule formation and induced G2/M cell cycle arrest in HeLa cells, revealing that a promising antiproliferative activity of compound 6m toward human cancer cells is probably caused by the tubulin polymerization inhibition.

Prognostic Impact of Hypoxia-Inducible miRNA-210 in Patients with Lung Adenocarcinoma

Objective. The aim of this study was to investigate the prognostic value of MicroRNA-210 (miR-210) expression in patients with non-small-cell lung cancer (NSCLC). Methods. We examined the miR-210 expression of samples of 80 patients, who underwent surgical resection at Fukushima Medical University from 2004 to 2007, by using quantitative RT-PCR. The relationship between miR-210 expression and clinicopathological factors as well as histological subtype was statistically analyzed. Results. miR-210 expression showed an inverse correlation with disease-free and overall survival in patients with NSCLC. Significant correlations were found between miR-210 expression and lymph node metastasis, late disease stages, and poor prognosis in patients with adenocarcinoma. Multivariate Cox analysis indicated that miR-210 expression was an independent prognostic factor for disease-free survival in patients with adenocarcinoma. Conclusions. We showed that miR-210 may be a prognostic biomarker for patients with NSCLC, especially for those with lung adenocarcinoma.

Pyrazine, 2-ethylpyridine, and 3-ethylpyridine are cigarette smoke components that alter the growth of normal and malignant human lung cells, and play a role in multidrug resistance development

Lung cancer is one of the few human diseases for which the primary etiological agent, cigarette smoke (CS), has been described; however, the precise role of individual cigarette smoke toxicant in tumor development and progression remains to be elusive. The purpose of this study was to assess in vitro the effects of previously identified cigarette smoke components, pyrazine, 2-ethylpyridine, and 3-ethylpyridine, on non-tumorigenic (MRC5) and adenocarcinomic (A549) human lung cell lines. Our data showed that the administration of three cigarette smoke components in combination perturbed the proliferation of both normal and adenocarcinomic cells. Study of malignant cells revealed that CS components were cytotoxic at high concentration (10(-6) M) and stimulatory in a dose-dependent manner at lower concentrations (10(-8) M to 10(-10) M). This adverse effect was enhanced when adenocarcinomic cells were maintained in hypoxia resembling intratumoral environment. Furthermore, exposure to pyrazine, 2-ethylpyridine, and 3-ethylpyridine induced oxidative stress in both normal and malignant cells. Finally, assessment of P-gp activity revealed that multidrug resistance was induced in CS component exposed adenocarcinomic lung cells and the induction was augmented in hypoxia. Taken together, pyrazine, 2-ethylpyridine, and 3-ethylpyridine adversely altered both normal and diseased lung cells in vitro and data collected from this study may help lung cancer patients to understand the importance of quitting smoking during lung cancer treatment.

Upregulated Annexin A1 promotes cellular invasion in triple-negative breast cancer

Annexin A1 (ANXA1) is a calcium-dependent phospholipid-linked protein, involved in anti-inflammatory effects, regulation of cellular differentiation, proliferation and apoptosis. While many studies have investigated the ANXA1 expression in various tumor types, the role of ANXA1 is not fully understood. Therefore, in the present study, we evaluated the ANXA1 expression in 211 breast cancer patients and compared the levels with clinicopathological factors. ANXA1 was positively expressed in 31 (14.7%) of the 211 cases in our cohort, and these positive cases were associated with triple-negative breast cancer (TNBC) (P=0.007) and venous invasion (P=0.028). The in vitro cell experiment found that the MDA-MB-231 cell line, which is a TNBC cell line, highly expressed ANXA1. Using this cell line, the functional role of ANXA1 in breast cancer was revealed and the knockdown of ANXA1 by specific siRNA demonstrated a significant reduction in cellular invasion. Further experiments indicated that ANXA1 was induced by hypoxia with hypoxia-inducible factor-1α induction. These results suggested that ANXA1, which enhanced breast cancer invasion and metastasis under hypoxia, were significantly associated with the worst patient outcome. This is particularly noted in TNBC, the group of breast cancer with the worst outcome for which new therapeutic implications are required.

Upregulation of miRNA3195 and miRNA374b Mediates the Anti-Angiogenic Properties of Melatonin in Hypoxic PC-3 Prostate Cancer Cells

Recently microRNAs (miRNAs) have been attractive targets with their key roles in biological regulation through post-transcription to control mRNA stability and protein translation. Though melatonin was known as an anti-angiogenic agent, the underlying mechanism of melatonin in PC-3 prostate cancer cells under hypoxia still remains unclear. Thus, in the current study, we elucidated the important roles of miRNAs in melatonin-induced anti-angiogenic activity in hypoxic PC-3 cells. miRNA array revealed that 33 miRNAs (>2 folds) including miRNA3195 and miRNA 374b were significantly upregulated and 16 miRNAs were downregulated in melatonin-treated PC-3 cells under hypoxia compared to untreated control. Melatonin significantly attenuated the expression of hypoxia-inducible factor (HIF)-1 alpha, HIF-2 alpha and vascular endothelial growth factor (VEGF) at mRNA level in hypoxic PC-3 cells. Consistently, melatonin enhanced the expression of miRNA3195 and miRNA 374b in hypoxic PC-3 cells by qRT-PCR analysis. Of note, overexpression of miRNA3195 and miRNA374b mimics attenuated the mRNA levels of angiogenesis related genes such as HIF-1alpha, HIF-2 alpha and VEGF in PC-3 cells under hypoxia. Furthermore, overexpression of miRNA3195 and miRNA374b suppressed typical angiogenic protein VEGF at the protein level and VEGF production induced by melatonin, while antisense oligonucleotides against miRNA 3195 or miRNA 374b did not affect VEGF production induced by melatonin. Also, overexpression of miR3195 or miR374b reduced HIF-1 alpha immunofluorescent expression in hypoxic PC-3 compared to untreated control. Overall, our findings suggest that upregulation of miRNA3195 and miRNA374b mediates anti-angiogenic property induced by melatonin in hypoxic PC-3 cells.

VEGF Splicing and the Role of VEGF Splice Variants: From Physiological-Pathological Conditions to Specific Pre-mRNA Splicing

During this past decade, the vascular endothelial growth factor (VEGF) pathway has been extensively studied. VEGF is a paradigm of molecular regulation since its expression is controlled at all possible steps including transcription, mRNA stability, translation, and pre-mRNA splicing. The latter form of molecular regulation is probably the least studied. This field has been neglected; yet different forms of VEGF with different sizes and different physiological properties issued from alternative splicing have been described a long time ago. Recently a new level of complexity was added to the field of splicing of VEGF pre-mRNA. Whereas thousands of publications have described VEGF as a pro-angiogenic factor, an alternative splicing event generates specific anti-angiogenic forms of VEGF that only differ from the others by a modification in the last six amino acids of the protein. According to the scientists who discovered these isoforms, which are indistinguishable from the pro-angiogenic ones with pan VEGF antibodies, some of the literature on VEGF is at least inexact if not completely false. Moreover, the presence of anti-angiogenic forms of VEGF may explain the disappointing efficacy of anti-VEGF therapies on the overall survival of patients with different forms of cancers and with wet age-related macular degeneration. This review focuses on the existence of the different alternative splice variants of VEGF and the molecular mechanisms associated with their expression and function.

Positron emission tomography to assess hypoxia and perfusion in lung cancer

In lung cancer, tumor hypoxia is a characteristic feature, which is associated with a poor prognosis and resistance to both radiation therapy and chemotherapy. As the development of tumor hypoxia is associated with decreased perfusion, perfusion measurements provide more insight into the relation between hypoxia and perfusion in malignant tumors. Positron emission tomography (PET) is a highly sensitive nuclear imaging technique that is suited for non-invasive in vivo monitoring of dynamic processes including hypoxia and its associated parameter perfusion. The PET technique enables quantitative assessment of hypoxia and perfusion in tumors. To this end, consecutive PET scans can be performed in one scan session. Using different hypoxia tracers, PET imaging may provide insight into the prognostic significance of hypoxia and perfusion in lung cancer. In addition, PET studies may play an important role in various stages of personalized medicine, as these may help to select patients for specific treatments including radiation therapy, hypoxia modifying therapies, and antiangiogenic strategies. In addition, specific PET tracers can be applied for monitoring therapy. The present review provides an overview of the clinical applications of PET to measure hypoxia and perfusion in lung cancer. Available PET tracers and their characteristics as well as the applications of combined hypoxia and perfusion PET imaging are discussed.

HOIL-1L functions as the PKCζ ubiquitin ligase to promote lung tumor growth

RATIONALE

Protein kinase C zeta (PKCζ) has been reported to act as a tumor suppressor. Deletion of PKCζ in experimental cancer models has been shown to increase tumor growth. However, the mechanisms of PKCζ down-regulation in cancerous cells have not been previously described.

OBJECTIVES

To determine the molecular mechanisms that lead to decreased PKCζ expression and thus increased survival in cancer cells and tumor growth.

METHODS

The levels of expression of heme-oxidized IRP2 ubiquitin ligase 1L (HOIL-1L), HOIL-1-interacting protein (HOIP), Shank-associated RH domain-interacting protein (SHARPIN), and PKCζ were analyzed by Western blot and/or quantitative real-time polymerase chain reaction in different cell lines. Coimmunoprecipitation experiments were used to demonstrate the interaction between HOIL-1L and PKCζ. Ubiquitination was measured in an in vitro ubiquitination assay and by Western blot with specific antibodies. The role of hypoxia-inducible factor (HIF) was determined by gain/loss-of-function experiments. The effect of HOIL-1L expression on cell death was investigated using RNA interference approaches in vitro and on tumor growth in mice models. Increased HOIL-1L and decreased PKCζ expression was assessed in lung adenocarcinoma and glioblastoma multiforme and documented in several other cancer types by oncogenomic analysis.

MEASUREMENTS AND MAIN RESULTS

Hypoxia is a hallmark of rapidly growing solid tumors. We found that during hypoxia, PKCζ is ubiquitinated and degraded via the ubiquitin ligase HOIL-1L, a component of the linear ubiquitin chain assembly complex (LUBAC). In vitro ubiquitination assays indicate that HOIL-1L ubiquitinates PKCζ at Lys-48, targeting it for proteasomal degradation. In a xenograft tumor model and lung cancer model, we found that silencing of HOIL-1L increased the abundance of PKCζ and decreased the size of tumors, suggesting that lower levels of HOIL-1L promote survival. Indeed, mRNA transcript levels of HOIL-1L were elevated in tumor of patients with lung adenocarcinoma, and in a lung adenocarcinoma tissue microarray the levels of HOIL-1L were associated with high-grade tumors. Moreover, we found that HOIL-1L expression was regulated by HIFs. Interestingly, the actions of HOIL-1L were independent of LUBAC.

CONCLUSIONS

These data provide first evidence of a mechanism of cancer cell adaptation to hypoxia where HIFs regulate HOIL-1L, which targets PKCζ for degradation to promote tumor survival. We provided a proof of concept that silencing of HOIL-1L impairs lung tumor growth and that HOIL-1L expression predicts survival rate in cancer patients suggesting that HOIL-1L is an attractive target for cancer therapy.

Genetic modification of hypoxia signaling in animal models and its effect on cancer

Conditions that cause hypoxemia or generalized tissue hypoxia, which can last for days, months, or even years, are very common in the human population and are among the leading causes of morbidity, disability, and mortality. Therefore, the molecular pathophysiology of hypoxia and its potential deleterious effects on human health are important issues at the forefront of biomedical research. Generalized hypoxia is a consequence of highly prevalent medical disorders that can severely reduce the capacity for O2 exchange between the air and pulmonary capillaries. In recent years, some of the key O2-dependent signaling pathways have been characterized at the molecular level. In particular, the prolyl hydroxylase (PHD)-hypoxia-inducible factor (HIF) cascade has emerged as the master regulator of a general gene expression program involved in cell/tissue/organ adaptation to hypoxia. Hypoxia has emerged as a critical factor in cancer because it can promote tumor initiation, progression, and resistance to therapy. Beyond its role in neovascularization as a mechanism of tumor adaptation to nutrient and O2 deprivation, hypoxia has been linked to prolonged cellular lifespan and immortalization, the generation of "oncometabolites", deregulation of stem cell proliferation, and inflammation, among other tumor hallmarks. Hypoxia may contribute to cancer through several independent pathways, the inter-connections of which have yet to be elucidated. Furthermore, the relevance of chronic hypoxemia in the initiation and progression of cancer has not been studied in depth in the whole organism. Therefore, we explore here the contributions of hypoxia to the whole organism by reviewing studies on genetically modified mice with alterations in the key molecular factors regulating hypoxia.

MiR-199a suppresses the hypoxia-induced proliferation of non-small cell lung cancer cells through targeting HIF1α

Deregulated microRNAs (miRNAs) are small noncoding RNAs that are involved in the carcinogenesis of various cancers, including lung cancer. HIF1a has been suggested to be a master regulator of hypoxia-induced cell proliferation. The relationship between HIF1a expression and the progression of non-small cell lung cancer (NSCLC) is not fully understood, and whether HIF1a expression is regulated by miRNAs in this process remains unclear. In this study, we found that the upregulation of HIF1a expression and the reduction in miR-199a levels were highly associated with NSCLC progression. NSCLC cells derived from cancer tissues with low miR-199a levels showed high HIF1a expression and high proliferation capacity. Moreover, HIF1a and glycolysis inhibitors suppress the proliferation of NSCLC cells. MiR-199a overexpression suppressed the hypoxia-induced proliferation of NSCLC cells through targeting elevated HIF1a and blocking the downstream upregulation of PDK1 without affecting AKT activation. Together, these results indicate that downregulation of miR-199a is essential for hypoxia-induced proliferation through derepressing the expression of HIF1a expression and affecting HIF1a mediated glycolytic pathway in NSCLC progression.

HIF1α is an independent prognostic factor for overall survival in advanced primary epithelial ovarian cancer - a study of the OVCAD Consortium

PURPOSE

Hypoxia is a common phenomenon encountered in solid cancers, leading to chemotherapy resistance and therefore to aggressiveness of the disease. The homeostatic response to hypoxia is mediated by hypoxiainducible factor-1 (HIF-1). The aim of this study was to investigate the impact of HIF1α in patients with primary epithelial ovarian cancer.

METHODS

In this multicentric study, 275 patients with advanced primary epithelial ovarian cancer were included. All patients underwent cytoreductive surgery with maximal surgical effort and adjuvant platinum-based chemotherapy. HIF1α expression was analyzed in tissue lysates, using an enzyme-linked immunosorbent assay.

RESULTS

HIF1α was detected in 79.3% of the tissue samples. Patients with increased HIF1α expression (cutoff: 80 pg/mg protein) in tumoral tissue lysates were more likely to have less favorable survival. HIF1α (P=0.009, hazard ratio [HR] 2.505, 95% confidence interval [95% CI] 1.252-5.013) together with International Federation of Gynecology and Obstetrics (III versus IV) (P=0.013, HR 0.540, 95% CI 0.332-0.878), histology (P=0.007, HR 2.748, 95% CI 1.315-5.743), presence of peritoneal carcinomatosis (P=0.014, HR 2.176, 95% CI 1.170-4.046), residual tumor mass (P=0.017, HR 1.641, 95% CI 1.091-2.468), and response to platinum-based chemotherapy (P<0.001, HR 8.131, 95% CI 5.13-12.88) were independent prognosis factors for overall survival. The independent prognostic factors for progression-free survival were International Federation of Gynecology and Obstetrics stage (P=0.01), histological subtypes (P=0.016), and presence of peritoneal carcinomatosis (P<0.05).

CONCLUSION

HIF1α overexpression in ovarian cancer is associated with poor overall survival, underlining the importance of hypoxia in this angiogenesis driven disease.

Correlations of lysyl oxidase with MMP2/MMP9 expression and its prognostic value in non-small cell lung cancer

Lysyl oxidase (LOX) has been reported to regulate tumor metastasis and has been found to involve in modification of extracellular matrix (ECM) in the context of tumorigenesis. The aim of this study is to determine the prognostic significance of LOX in non-small cell lung cancer (NSCLC) patients and to examine the correlation between LOX expression and ECM remodeling-associated MMP2/MMP9 in NSCLC tissues. The mRNA expression of LOX, MMP2 and MMP9 was investigated by quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) in 30 NSCLC patients. The protein expression of LOX was measured by immunohistochemistry (IHC) in 110 paraffin-embedded tissues with NSCLC and the protein expression of MMP2/MMP9 was measured by in 30 NSCLC patients. The correlation between LOX expression and clinical parameters and MMP2/MMP9 was analyzed by appropriate statistics. The Kaplan-Meier method, univariate and multivariate regression analysis was used to analyze the correlation between LOX expression and overall survival (OS). The relative mRNA expression or protein expression of LOX were significantly higher in NSCLC tumor tissues than in the corresponding noncancerous tissues (P < 0.05). High LOX expression was significantly associated with MMP2, MMP9, tumor size, lymph node metastasis, pathological stage and OS (P < 0.05). Univariate and multivariate analysis showed that LOX was an independent prognostic factor for OS. Our results indicate that LOX may play a role in the metastasis of NSCLC by promoting MMP2/MMP9 expression. LOX expression is an independent prognostic factor in OS in NSCLC.

Prognosis value of HIF-1α expression in patients with non-small cell lung cancer

BACKGROUND

Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that plays a critical role in the development and progression of tumors. Various studies evaluating the prognostic value of HIF-1α in patients with lung cancer (LC) remain controversial. To comprehensively and quantitatively summarize the evidence on the effect of HIF-1α expression on the survival of patients with LC, a meta-analysis was carried out.

MATERIAL AND METHODS

Electronic databases were used to identify published studies before August 31st, 2013. Studies were assessed for quality using REMARK. Data were collected comparing overall survival in patients with high HIF-1α expression with those with low expression.

RESULTS

Totally, 13 papers including 1420 patients were subjected to final analysis. The combined hazard ratio (HR) was 1.60 (95% CI: 1.14-2.25, P=0.007), suggesting that high expression of HIF-1α was an indicator of poor prognosis. Further, when stratified by LC histological type (SCLC and NSCLC), study region (Asia and Europe), cut-off values (10%), tumor stage (I-III and I-IV), antibody for IHC (H1α67 and ESEE 122), and HR estimated method (univariate/multivariate analysis), most of the results were statistically significant.

CONCLUSIONS

Taken together, this meta-analysis revealed that HIF-1α overexpression might be a predicative factor of poor prognosis for NSCLC particularly in Asia.

Molecular responses to hypoxia-inducible factor 1α and beyond

Cellular response to changes in oxygen tension during normal development or pathologic processes is, in part, regulated by hypoxia-inducible factor (HIF), an oxygen-sensitive transcription factor. HIF activity is primarily controlled through post-translational modifications and stabilization of HIF-1α and HIF-2α proteins and is regulated by a number of cellular pathways involving both oxygen-dependent and -independent mechanisms. Stabilization of HIF-1α activates transcription of genes that participate in key pathways in carcinogenesis, such as angiogenesis, dedifferentiation, and invasion. Since its discovery more than two decades ago, HIF-1α has become a hot topic in molecular research and has been implicated not only in disease pathology but also in prognosis. In this review, we will focus on recent insights into HIF-1α regulation, function, and gene expression. We will also discuss emerging data on the involvement of HIF in cancer prognosis and therapeutic interventions.

Prognostic role of hypoxic inducible factor expression in non-small cell lung cancer: a meta-analysis

INTRODUCTION

Reported prognostic roles of hypoxic inducible factor (HIF) expression in non-small cell lung cancer (NSCLC) have varied. This meta-analysis aimed to examine the relationship between HIF expression and clinical outcome in NSCLC patients.

METHODS

PubMed were used to identify relevant literature with the last report up to December 20th, 2012. After careful review, survival data were collected from eligible studies. We completed the meta-analysis using Stata statistical software (Version 11) and combined hazard ratio (HR) for overall survival (OS). Subgroup specificity, heterogeneity and publication bias were also assessed. All of the results were verified by two persons to ensure accuracy.

RESULTS

Eight studies were finally stepped into this meta-analysis in which seven had available data for HIF-1α and three for HIF-2α. Combined HRs suggested that higher expression of HIF1α had a negative impact on NSCLC patient survival (HR=1.50; 95%CI =1.07-2.10; p=0.019). The expression of HIF-2α was also relative to a poorer survival (HR=2.02; 95%CI =1.47-2.77; p=0.000). No bias existed in either of the two groups.

CONCLUSION

This study suggests that elevations of HIF-1α and HIF- 2α expression are both associated with poor outcome for patients with NSCLC. The data support further and high quality investigation of HIF expression for predicting poor outcome in patients with NSCLC.

Expression and significance of hypoxia inducible factor-1α and lysyl oxidase in non-small cell lung cancer

OBJECT

To detect expression of hypoxia inducible factor-1α (HIF-1α) and lysyl oxidase (LOX) in non-small cell lung cancer (NSCLC) and explore their roles in prognosis.

METHODS

The mRNA levels of HIF-1α and LOX were investigated by real-time reverse-transcriptase polymerase chain reaction in 40 cases of tumour and paired normal tissues. In addition, protein expression of HIF-1α and LOX was examined by immunohistochemistry in 82 cases of tumour and 45 paired normal tissues. The relationship between HIF-1α or LOX and clinicopathologic characteristics, as well as the correlation between HIF-1α and LOX, were also examined. Kaplan-Meier survival curves and the log-rank test were used to analyze progression-free survival.

RESULTS

HIF-1α or LOX mRNA levels in tumor tissues was significantly higher than those in paired normal tissues (p<0.01). Positive HIF-1α or LOX protein expression in tumor tissues was noted in 46/82 (56.1%) and 49/82 (59.8%) of the cases, respectively, being significantly higher than those in paired normal tissues (p<0.05). There was significant correlation between the expression of HIF-1α or LOX and tumor size, lymph node metastasis and pathological stage (p<0.05). The expression of HIF-1α and LOX had a significant inverse impact on survival of patients with NSCLC.

CONCLUSION

HIF-1α and LOX may play a pivotal role in the development of NSCLC, and may act in synergy to promote the progression of NSCLC.

Analysis of Expression of Vascular Endothelial Growth Factor A and Hypoxia Inducible Factor-1alpha in Patients Operated on Stage I Non-Small-Cell Lung Cancer

Objectives. Recent studies show that expression of hypoxia inducible factor-1alpha (HIF-1α) favours expression of vascular endothelial growth factor A (VEGF-A), and these biomarkers are linked to cellular proliferation, angiogenesis, and metastasis in different cancers. We analyze expression of HIF-1α and VEGF-A to clinicopathologic features and survival of patients operated on stage I non-small-cell lung cancer. Methodology. Prospective study of 52 patients operated on with stage I. Expression of VEGF-A and HIF-1α was performed through real-time quantitative polymerase chain reaction (qRT-PCR). Results. Mean age was 64.7 and 86.5% of patients were male. Stage IA represented 23.1% and stage IB 76.9%. Histology classification was 42.3% adenocarcinoma, 34.6% squamous cell carcinoma, and 23.1% others. Median survival was 81.0 months and 5-year survival 67.2%. There was correlation between HIF-1α and VEGF-A (P = 0.016). Patients with overexpression of HIF-1α had a tendency to better survival with marginal statistical significance (P = 0.062). Patients with overexpression of VEGF-A had worse survival, but not statistically significant (P = 0.133). Conclusion. The present study revealed that VEGF-A showed correlation with HIF-1α. HIF-1α had a tendency to protective effect with a P value close to statistical significance. VEGF-A showed a contrary effect but without statistical significance.

Loss of the tumor suppressor LKB1 promotes metabolic reprogramming of cancer cells via HIF-1α

One of the major metabolic changes associated with cellular transformation is enhanced nutrient utilization, which supports tumor progression by fueling both energy production and providing biosynthetic intermediates for growth. The liver kinase B1 (LKB1) is a serine/threonine kinase and tumor suppressor that couples bioenergetics to cell-growth control through regulation of mammalian target of rapamycin (mTOR) activity; however, the influence of LKB1 on tumor metabolism is not well defined. Here, we show that loss of LKB1 induces a progrowth metabolic program in proliferating cells. Cells lacking LKB1 display increased glucose and glutamine uptake and utilization, which support both cellular ATP levels and increased macromolecular biosynthesis. This LKB1-dependent reprogramming of cell metabolism is dependent on the hypoxia-inducible factor-1α (HIF-1α), which accumulates under normoxia in LKB1-deficient cells and is antagonized by inhibition of mTOR complex I signaling. Silencing HIF-1α reverses the metabolic advantages conferred by reduced LKB1 signaling and impairs the growth and survival of LKB1-deficient tumor cells under low-nutrient conditions. Together, our data implicate the tumor suppressor LKB1 as a central regulator of tumor metabolism and growth control through the regulation of HIF-1α-dependent metabolic reprogramming.

Hypoxia imaging with 18F-fluoroerythronitroimidazole integrated PET/CT and immunohistochemical studies in non-small cell lung cancer

PURPOSE

(18)F-fluoroerythronitroimidazole ((18)F-FETNIM) PET/CT allows a noninvasive assessment of tumor hypoxia. The purpose of this study was to evaluate a noninvasive and simplicity parameter for quantization of (18)F-FETNIM uptake with expectations to predict survival in non-small cell lung cancer surgical patients and investigate the relationship between (18)F-FETNIM uptake and molecular markers related to hypoxia, glucose metabolism, and angiogenesis.

PATIENTS AND METHODS

Thirty-two patients with biopsy-proven non-small cell lung cancer for surgical treatment were enrolled from March 2007 to February 2011. All patients had PET/CT studies with (18)F-FETNIM and subsequently underwent surgery. Twenty-five patients had stage II disease of surgical staging only for statistical analysis. The tumor-to-mediastinum (T/Me) ratio was calculated and correlated with survival and immunohistochemical staining of hypoxia inducible factor 1α (HIF-1α), glucose transporter 1 (GLUT-1), and vascular endothelial growth factor (VEGF).

RESULTS

The actuarial survival was worse for patients showing a high T/Me ratio, the best discriminative cutoff value being 1.9. A statistically significant worse survival was noted in patients having a tumor with a T/Me ratio of 1.9 or greater, compared with patients showing a tumor with a T/Me ratio of less than 1.9, a 3-year survival of 43.8% and 88.9%, respectively (P = 0.034). There was a positive correlation between T/Me ratio and HIF-1α (P = 0.023), GLUT-1 (P = 0.035), and VEGF (P = 0.042).

CONCLUSIONS

T/Me ratio provides a noninvasive parameter for quantization of (18)F-FETNIM uptake on PET/CT. T/Me ratio is correlated with a worse outcome and with the expression of HIF-1α, GLUT-1, and VEGF, all up-regulated under hypoxic conditions.

Factor-inhibiting hypoxia-inducible factor expression in patients with high-risk locally advanced renal cell carcinoma and its relationship with tumor progression

Hypoxia-inducible factor (HIF) plays an important role in renal cell carcinoma (RCC) associated with angiogenesis. Factor-inhibiting HIF (FIH), which is the upstream mediator protein of HIF, is receiving more attention today. In the present study, the role of FIH expression in high-risk locally advanced renal cell carcinoma (LARCC) was explored. Eighty-eight high-risk LARCC cases were divided into two groups based on their prognosis. Using immunohistochemical staining, the correlations of FIH expression along with clinicopathological factors, progression-free survival (PFS), and overall survival (OS) were analyzed. FIH was mainly located in the cytoplasm (34/88) and nucleus (31/88) of the renal tumor cell. Nuclear negative expression or cytoplasmic positive expression of FIH were associated with an increased risk of disease progression (p = 0.007 and p < 0.001, respectively) and worse OS (p = 0.020 and p = 0.008, respectively). Using the group with nuclear and cytoplasmic FIH negative expression as reference, further stratified analysis found that the exclusive nuclear FIH expression group had a better PFS and OS [hazard ratio (HR) = 0.153, p = 0.07 and HR = 0, p = 0.961, respectively], and the exclusive cytoplasmic FIH positive group experienced the worst PFS and OS (HR = 2.876, p = 0.005 and HR = 2.799, p = 0.034, respectively). In addition, nuclear negative expression of FIH was associated with a significant negative predictive value for the effect of interferon-alpha (IFN-α) on PFS (p = 0.045). The nuclear negative and cytoplasmic positive expressions of FIH were identified not only as risk factors for disease progression in high-risk LARCC postoperative patients, but also to be associated with poor OS. Furthermore, the nuclear negative expression of FIH may be a promising biomarker for postoperative adjuvant therapy.

[Advances of hypoxia and lung cancer]

肺癌是我国发病率和死亡率增长最快, 对人群健康和生命威胁最大的恶性肿瘤, 其发生发展机制尚未完全清楚。肿瘤的低氧微环境发现于1955年, 而肺癌组织低氧直至2006年才被成功检测到。随着研究的深入, 低氧对肺癌的影响不仅限于对放疗的抵抗作用, 而且还会通过一个重要的促癌分子低氧诱导因子(hypoxia inducible factor, HIF)以及其调节蛋白脯氨酸羟化酶(prolyl hydroxylase domain, PHD)和希佩尔•林道病基因产物(product of von Hippel-Lindau gene, pVHL)对肺癌的发生发展、侵袭转移、化疗耐药以及预后等产生重要的调节作用。因此, 低氧、HIF、PHD和pVHL必将成为十分有潜力的肺癌治疗靶点。

High expression of glucose transporter 1 on primary lesions of esophageal squamous cell carcinoma is associated with hematogenous recurrence

PURPOSE

Glucose transporter type 1 (Glut1) plays a crucial role in cancer-specific metabolism to adapt to the rapid growth and tumor microenvironment in diverse malignant tumors. This study examined the clinical, pathological, and prognostic features of Glut1 expression on primary lesions of esophageal squamous cell carcinoma.

METHODS

Immunohistochemical staining of Glut1 and CD34 was performed using paraffin-embedded sections of tissues obtained from 145 resectable esophageal squamous cell carcinoma patients without preoperative treatment. Microvessel density was calculated from CD34 staining.

RESULTS

Glut1 positivity was observed in 41 patients (28.2 %) and associated with depth of invasion [odds ratio (OR) 2.984; 95 % confidence interval (CI) 1.208-7.371; P = 0.018] and vascular invasion (OR 2.771; 95 % CI 1.118-6.871; P = 0.028) in multivariate analysis. Glut1 positivity was a significant disadvantage to both relapse-free survival [hazard ratio (HR) 2.021; 95 % CI 1.100-3.712; P = 0.023] and esophageal cancer-specific survival (HR 2.223; 95 % CI 1.121-4.411; P = 0.022) in univariate Cox hazard analysis, but was not independently associated with relapse-free survival or cancer-specific survival in multivariate analysis. The relationship between Glut1 expression and first relapse site was investigated. Glut1 positivity was not associated with lymph node recurrence (HR 1.009; 95 % CI 0.402-2.530; P = 0.985) but was significantly associated with hematogenous recurrence (HR 3.701; 95 % CI 1.655-8.273; P = 0.001) in univariate Cox hazard analysis. Microvessel density was calculated to evaluate angiogenesis, and it was observed that Glut1 positivity was significantly associated with high microvessel density (P < 0.001).

CONCLUSIONS

Glut1 expression was associated with hematogenous recurrence. The findings provide evidence of the significance of Glut1 expression as a biomarker.

Hypoxia-induced reactive oxygen species cause chromosomal abnormalities in endothelial cells in the tumor microenvironment

There is much evidence that hypoxia in the tumor microenvironment enhances tumor progression. In an earlier study, we reported abnormal phenotypes of tumor-associated endothelial cells such as those resistant to chemotherapy and chromosomal instability. Here we investigated the role of hypoxia in the acquisition of chromosomal abnormalities in endothelial cells. Tumor-associated endothelial cells isolated from human tumor xenografts showed chromosomal abnormalities, >30% of which were aneuploidy. Aneuploidy of the tumor-associated endothelial cells was also shown by simultaneous in-situ hybridization for chromosome 17 and by immunohistochemistry with anti-CD31 antibody for endothelial staining. The aneuploid cells were surrounded by a pimonidazole-positive area, indicating hypoxia. Human microvascular endothelial cells expressed hypoxia-inducible factor 1 and vascular endothelial growth factor A in response to either hypoxia or hypoxia-reoxygenation, and in these conditions, they acquired aneuploidy in 7 days. Induction of aneuploidy was inhibited by either inhibition of vascular endothelial growth factor signaling with vascular endothelial growth factor receptor 2 inhibitor or by inhibition of reactive oxygen species by N-acetyl-L-cysteine. These results indicate that hypoxia induces chromosomal abnormalities in endothelial cells through the induction of reactive oxygen species and excess signaling of vascular endothelial growth factor in the tumor microenvironment.

Pushing tumor cells towards a malignant phenotype: stimuli from the microenvironment, intercellular communications and alternative roads

The tumor microenvironment produces different types of stimuli capable of endowing tumor cells with an aggressive behavior that is characterized by increased motility, invasiveness and propensity to metastasize, gain of a tumor-initiating phenotype, and drug resistance. The following classes of stimuli have been reported to promote such a malignant phenotype: (i) solid- or fluid-induced stress; (ii) altered composition of the extracellular matrix; (iii) hypoxia and low pH; (iv) innate and adaptive immune responses; (v) antitumor drugs. The simultaneous presence of more than one of these stimuli, as likely occurs in vivo, may lead to synergistic interactions in the induction of malignant traits. In many cases, the gain of a malignant phenotype is not the result of a direct effect of the stimuli on tumor cells but, rather, a stimulus-promoted cross-talk between tumor cells and other cell types within the tumor microenvironment. This cross-talk is mainly mediated by two classes of molecules: paracrine factors and adhesion receptors. Stimuli that promote a malignant phenotype can promote additional outcomes in tumor cells, including autophagy and cell death. We summarize here the available evidence about the variables that induce tumor cells to take one or the other of these roads in response to the same stimuli. At the end of this review, we address some unanswered questions in this domain and indicate future directions of research.

Non-FDG-avid primary papillary thyroid carcinoma may not differ from FDG-avid papillary thyroid carcinoma

BACKGROUND

FDG (2-[(18)F]Fluoro-2-D-deoxyglucose-positron emission tomography (PET)/computed tomography (CT), which can detect a change in glucose metabolism in cancer cells, has been introduced as a diagnostic and prognostic tool in papillary thyroid carcinoma (PTC). However, differences in the clinicopathological and biological characteristics between primary PTCs with FDG uptake and those without FDG uptake are not well established.

METHODS

A total of 188 patients with PTC who had preoperative PET/CT scans were enrolled to compare the differences of clinicopathological parameters between FDG-avid (F-PTC; n = 150) and non-FDG-avid tumors (FN-PTC; n = 38). Immunohistochemical staining for glucose transporter (GLUT)-1 and hypoxia-inducible factor-1 alpha (HIF-1α) was performed.

RESULTS

FN-PTCs were smaller; had a lower incidence of lymphatic invasion, vascular invasion, multifocality, and central lymph node metastasis; and had a lower maximum standardized uptake value than F-PTCs. After exclusion of high-risk patients for recurrence, FN-PTCs remained smaller (p < 0.001) and had less lymphatic invasion (p = 0.061). Among tumors larger than the spatial resolution of the PET/CT scan, macrocalcification was more frequent in FN-PTC than in F-PTC (p = 0.043). While FN-PTC and F-PTC showed no difference in GLUT-1 expression (50% vs. 75%, p = 0.363), FN-PTC showed lower HIF-1α immunoreactivity than F-PTC (25.0% vs. 75.0%, p = 0.032).

CONCLUSION

Tumor size and macrocalcification are clinicopathological differences between FN-PTC and F-PTC. Biologically, HIF-1α may be responsible for increased FDG uptake in PTC.

Overexpression of HIF-2α, TWIST, and CXCR4 is associated with lymph node metastasis in papillary thyroid carcinoma

This study aimed to examine HIF-2α, TWIST, and CXCR4 expression in papillary thyroid carcinoma (PTC) and assesses the association of their expression with clinicopathological indicators. HIF-2α, TWIST, and CXCR4 protein expression in 129 PTCs, 61 nodular hyperplasia, and 118 normal thyroid tissue specimens was analyzed using immunohistochemistry. The protein expression levels of these three molecules were upregulated in PTCs. High protein expression of HIF-2α, TWIST, and CXCR4 was significantly correlated with lymph node metastasis (LNM) (P < 0.001). Furthermore, HIF-2α, TWIST, and CXCR4 protein expression was correlated with one another. Concomitant high expression of these molecules had stronger correlation with LNM than did each alone (P = 0.032 for HIF-2α/TWIST, P < 0.001 for HIF-2α/CXCR4, P = 0.018 for TWIST/CXCR4, and P < 0.001 for HIF-2α/TWIST/CXCR4). Additionally, HIF-2α, TWIST, and CXCR4 mRNA expression were assessed in 30 PTCs, 10 nodular hyperplasia, and 10 normal thyroid tissue specimens using real-time RT-PCR. TWIST and CXCR4 mRNA expression levels were up-regulated in PTCs, and high mRNA expression of TWIST and CXCR4 was significantly correlated with LNM (P = 0.005 and P = 0.010, resp.). These results demonstrated that the evaluation of HIF-2α, TWIST, and CXCR4 expression in PTC may be useful in predicting the risk of LNM.