Epidermal Growth Factor Receptor–Mediated Signal Transduction in the Development and Therapy of Gliomas

A Multicenter, Phase II, Randomized, Noncomparative Clinical Trial of Radiation and Temozolomide with or without Vandetanib in Newly Diagnosed Glioblastoma Patients

PURPOSE

Vandetanib, a tyrosine kinase inhibitor of KDR (VEGFR2), EGFR, and RET, may enhance sensitivity to chemotherapy and radiation. We conducted a randomized, noncomparative, phase II study of radiation (RT) and temozolomide with or without vandetanib in patients with newly diagnosed glioblastoma (GBM).

EXPERIMENTAL DESIGN

We planned to randomize a total of 114 newly diagnosed GBM patients in a ratio of 2:1 to standard RT and temozolomide with (76 patients) or without (38 patients) vandetanib 100 mg daily. Patients with age ≥ 18 years, Karnofsky performance status (KPS) ≥ 60, and not on enzyme-inducing antiepileptics were eligible. Primary endpoint was median overall survival (OS) from the date of randomization. Secondary endpoints included median progression-free survival (PFS), 12-month PFS, and safety. Correlative studies included pharmacokinetics as well as tissue and serum biomarker analysis.

RESULTS

The study was terminated early for futility based on the results of an interim analysis. We enrolled 106 patients (36 in the RT/temozolomide arm and 70 in the vandetanib/RT/temozolomide arm). Median OS was 15.9 months [95% confidence interval (CI), 11.0-22.5 months] in the RT/temozolomide arm and 16.6 months (95% CI, 14.9-20.1 months) in the vandetanib/RT/temozolomide (log-rank P = 0.75).

CONCLUSIONS

The addition of vandetanib at a dose of 100 mg daily to standard chemoradiation in patients with newly diagnosed GBM or gliosarcoma was associated with potential pharmacodynamic biomarker changes and was reasonably well tolerated. However, the regimen did not significantly prolong OS compared with the parallel control arm, leading to early termination of the study.

Proteomic profiling of patient-derived glioblastoma xenografts identifies a subset with activated EGFR: implications for drug development

The development of drugs to inhibit glioblastoma (GBM) growth requires reliable pre-clinical models. To date, proteomic level validation of widely used patient-derived glioblastoma xenografts (PDGX) has not been performed. In the present study, we characterized 20 PDGX models according to subtype classification based on The Cancer Genome Atlas criteria, TP53, PTEN, IDH 1/2, and TERT promoter genetic analysis, EGFR amplification status, and examined their proteomic profiles against those of their parent tumors. The 20 PDGXs belonged to three of four The Cancer Genome Atlas subtypes: eight classical, eight mesenchymal, and four proneural; none neural. Amplification of EGFR gene was observed in 9 of 20 xenografts, and of these, 3 harbored the EGFRvIII mutation. We then performed proteomic profiling of PDGX, analyzing expression/activity of several proteins including EGFR. Levels of EGFR phosphorylated at Y1068 vary considerably between PDGX samples, and this pattern was also seen in primary GBM. Partitioning of 20 PDGX into high (n = 5) and low (n = 15) groups identified a panel of proteins associated with high EGFR activity. Thus, PDGX with high EGFR activity represent an excellent pre-clinical model to develop therapies for a subset of GBM patients whose tumors are characterized by high EGFR activity. Further, the proteins found to be associated with high EGFR activity can be monitored to assess the effectiveness of targeting EGFR. The development of drugs to inhibit glioblastoma (GBM) growth requires reliable pre-clinical models. We validated proteomic profiles using patient-derived glioblastoma xenografts (PDGX), characterizing 20 PDGX models according to subtype classification based on The Cancer Genome Atlas (TCGA) criteria, TP53, PTEN, IDH 1/2, and TERT promoter genetic analysis, EGFR amplification status, and examined their proteomic profiles against those of their parent tumors. Proteins found to be associated with high EGFR activity represent potential biomarkers for GBM monitoring.

Loss of PHD3 allows tumours to overcome hypoxic growth inhibition and sustain proliferation through EGFR

Solid tumours are exposed to microenvironmental factors such as hypoxia that normally inhibit cell growth. However, tumour cells are capable of counteracting these signals through mechanisms that are largely unknown. Here we show that the prolyl hydroxylase PHD3 restrains tumour growth in response to microenvironmental cues through the control of EGFR. PHD3 silencing in human gliomas or genetic deletion in a murine high-grade astrocytoma model markedly promotes tumour growth and the ability of tumours to continue growing under unfavourable conditions. The growth-suppressive function of PHD3 is independent of the established PHD3 targets HIF and NF-κB and its hydroxylase activity. Instead, loss of PHD3 results in hyperphosphorylation of epidermal growth factor receptor (EGFR). Importantly, epigenetic/genetic silencing of PHD3 preferentially occurs in gliomas without EGFR amplification. Our findings reveal that PHD3 inactivation provides an alternative route of EGFR activation through which tumour cells sustain proliferative signalling even under conditions of limited oxygen availability.

Little is known on how solid tumours overcome growth inhibitory signals within its hypoxic microenvironment. Here Henze et al. show that oxygen sensor PHD3 is frequently lost in gliomas, and that this loss hyperactivates EGFR signaling to sustain tumour cell proliferation and survival in hypoxia.

PHD3 regulates EGFR internalization and signalling in tumours

Tumours exploit their hypoxic microenvironment to induce a more aggressive phenotype, while curtailing the growth-inhibitory effects of hypoxia through mechanisms that are poorly understood. The prolyl hydroxylase PHD3 is regulated by hypoxia and plays an important role in tumour progression. Here we identify PHD3 as a central regulator of epidermal growth factor receptor (EGFR) activity through the control of EGFR internalization to restrain tumour growth. PHD3 controls EGFR activity by acting as a scaffolding protein that associates with the endocytic adaptor Eps15 and promotes the internalization of EGFR. In consequence, loss of PHD3 in tumour cells suppresses EGFR internalization and hyperactivates EGFR signalling to enhance cell proliferation and survival. Our findings reveal that PHD3 inactivation provides a novel route of EGFR activation to sustain proliferative signalling in the hypoxic microenvironment.

Rare occurrence of EGFRvIII deletion in head and neck squamous cell carcinoma

BACKGROUND

The epidermal growth factor receptor (EGFR) is a transmembrane tyrosine kinase receptor and is overexpressed in up to 90% of head and neck squamous cell carcinoma (HNSCC) cases. The EGFR truncation mutation, EGFR variant III (EGFRvIII), harbors an in-frame deletion of exons 2-7 (801 bp) that leads to the constitutive activation of downstream signaling. EGFRvIII has been reported in ∼40% of glioblastomas (GBM), but its presence in HNSCC remains controversial.

METHODS

EGFRvIII deletion in 638 HNSCC samples was analyzed using: (i) quantitative Real-Time polymerase chain reaction (qRT-PCR) on 108 HNSCC samples with direct detection of the EGFRvIII breakpoint, (ii) RNA-Seq analysis on 7 HNSCC tumor tissues and 425 The Cancer Genome Atlas (TCGA) HNSCC samples, and (iii) immunohistochemistry (IHC) for EGFRvIII using an established antibody (L8A4) on a tissue microarray of 105 HNSCC samples.

RESULTS

qRT-PCR did not show the presence of EGFRvIII in any of the samples analyzed. Furthermore, we could not detect any EGFRvIII transcripts in the RNA-Seq data of the seven HNSCC samples. However, 2 samples out of 425 TCGA HNSCC samples had EGFRvIII specific reads. EGFRvIII IHC results were assessed as negative for all samples.

CONCLUSION

Our results firmly establish that EGFRvIII is very rare in HNSCC as only 2 out of 638 (0.31%) samples we analyzed overall, or 2 out of 540 (0.37%) using mRNA based approaches, were positive for EGFRvIII. EGFRvIII is extremely rare in HNSCC and the clinical significance remains unclear. We propose not to include EGFRvIII testing in regular diagnostic tests for HNSCC.

EGFR-dependent mechanisms in glioblastoma: towards a better therapeutic strategy

Glioblastoma is a particularly resilient cancer, and while therapies may be able to reach the brain by crossing the blood-brain barrier, they then have to deal with a highly invasive tumor that is very resistant to DNA damage. It seems clear that in order to kill aggressive glioma cells more efficiently and with fewer side effects on normal tissue, there must be a shift from classical cytotoxic chemotherapy to more targeted therapies. Since the epidermal growth factor receptor (EGFR) is altered in almost 50% of glioblastomas, it currently represents one of the most promising therapeutic targets. In fact, it has been associated with several distinct steps in tumorigenesis, from tumor initiation to tumor growth and survival, and also with the regulation of cell migration and angiogenesis. However, inhibitors of the EGFR kinase have produced poor results with this type of cancer in clinical trials, with no clear explanation for the tumor resistance observed. Here we will review what we know about the expression and function of EGFR in cancer and in particular in gliomas. We will also evaluate which are the possible molecular and cellular escape mechanisms. As a result, we hope that this review will help improve the design of future EGFR-targeted therapies for glioblastomas.

Taking advantage of neural development to treat glioblastoma

Glioblastoma (GBM) is by far the most common and most malignant primary adult brain tumor (World Health Organization grade IV), containing a fraction of stem-like cells that are highly tumorigenic and multipotent. Recent research has revealed that GBM stem-like cells play important roles in GBM pathogenesis. GBM is thought to arise from genetic anomalies in glial development. Over the past decade, a wide range of studies have shown that several signaling pathways involved in neural development, including basic helix-loop-helix, Wnt-β-catenin, bone morphogenetic proteins-Smads, epidermal growth factor-epidermal growth factor receptor, and Notch, play important roles in GBM pathogenesis. In this review, we highlight the significance of these pathways in the context of developing treatments for GBM. Extrapolating knowledge and concepts from neural development will have significant implications for designing better strategies with which to treat GBM.

Quantitative assessment of intragenic receptor tyrosine kinase deletions in primary glioblastomas: their prevalence and molecular correlates

Intragenic deletion is the most common form of activating mutation among receptor tyrosine kinases (RTK) in glioblastoma. However, these events are not detected by conventional DNA sequencing methods commonly utilized for tumor genotyping. To comprehensively assess the frequency, distribution, and expression levels of common RTK deletion mutants in glioblastoma, we analyzed RNA from a set of 192 glioblastoma samples from The Cancer Genome Atlas for the expression of EGFRvIII, EGFRvII, EGFRvV (carboxyl-terminal deletion), and PDGFRAΔ8,9. These mutations were detected in 24, 1.6, 4.7, and 1.6 % of cases, respectively. Overall, 29 % (55/189) of glioblastomas expressed at least one RTK intragenic deletion transcript in this panel. For EGFRvIII, samples were analyzed by both quantitative real-time PCR (QRT-PCR) and single mRNA molecule counting on the Nanostring nCounter platform. Nanostring proved to be highly sensitive, specific, and linear, with sensitivity comparable or exceeding that of RNA seq. We evaluated the prognostic significance and molecular correlates of RTK rearrangements. EGFRvIII was only detectable in tumors with focal amplification of the gene. Moreover, we found that EGFRvIII expression was not prognostic of poor outcome and that neither recurrent copy number alterations nor global changes in gene expression differentiate EGFRvIII-positive tumors from tumors with amplification of wild-type EGFR. The wide range of expression of mutant alleles and co-expression of multiple EGFR variants suggests that quantitative RNA-based clinical assays will be important for assessing the relative expression of intragenic deletions as therapeutic targets and/or candidate biomarkers. To this end, we demonstrate the performance of the Nanostring assay in RNA derived from routinely collected formalin-fixed paraffin-embedded tissue.

Association between the epidermal growth factor +61 G/A polymorphism and glioma risk: a meta-analysis

Background

Gliomas account for almost 80% of primary malignant brain tumors. Epidermal growth factor (EGF) is an interesting research candidate in which to look for genetic polymorphisms because of its role in mitogenesis and proliferation. Extensive studies have found that a single nucleotide polymorphism (SNP) +61G/A (rs4444903) in the EGF gene is associated with the susceptibility of glioma, however, the results have been controversial. Furthermore, the association between EGF +61G/A polymorphism with the development and grade progress of glioma has not been established.

Methods

We examined the association of EGF +61G/A polymorphism and glioma by performing a meta-analysis. Nine studies testing the associations between EGF +61G/A polymorphism and risk of glioma with 1758 cases and 2823 controls were retrieved. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association. The pooled ORs were performed for the allele model, codominant model, dominant model, and recessive model, respectively.

Results

Overall, this meta-analysis showed significant associations between the EGF +61G/A polymorphism and glioma susceptibility in all four genetic models. However, in the stratified analysis by the grade of glioma, we only found this association existed in patients with Grade IV glioblastoma, but not in patients with Grade I-III glioma. We further compared EGF +61G/A polymorphism in patients with glioblastoma and Grade I-III glioma accordingly, the stronger association between the EGF +61G/A polymorphism and the malignancy of glioma was found.

Conclusions

The results of this meta-analysis suggested that the EGF +61G/A polymorphism is associated with both the susceptibility of glioma and the malignance of glioma.

Targeting class IA PI3K isoforms selectively impairs cell growth, survival, and migration in glioblastoma

The phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is frequently activated in human cancer and plays a crucial role in glioblastoma biology. We were interested in gaining further insight into the potential of targeting PI3K isoforms as a novel anti-tumor approach in glioblastoma. Consistent expression of the PI3K catalytic isoform PI3K p110α was detected in a panel of glioblastoma patient samples. In contrast, PI3K p110β expression was only rarely detected in glioblastoma patient samples. The expression of a module comprising the epidermal growth factor receptor (EGFR)/PI3K p110α/phosphorylated ribosomal S6 protein (p-S6) was correlated with shorter patient survival. Inhibition of PI3K p110α activity impaired the anchorage-dependent growth of glioblastoma cells and induced tumor regression in vivo. Inhibition of PI3K p110α or PI3K p110β also led to impaired anchorage-independent growth, a decreased migratory capacity of glioblastoma cells, and reduced the activation of the Akt/mTOR pathway. These effects were selective, because targeting of PI3K p110δ did not result in a comparable impairment of glioblastoma tumorigenic properties. Together, our data reveal that drugs targeting PI3K p110α can reduce growth in a subset of glioblastoma tumors characterized by the expression of EGFR/PI3K p110α/p-S6.

Phase I/II study of erlotinib and temsirolimus for patients with recurrent malignant gliomas: North American Brain Tumor Consortium trial 04-02

BACKGROUND

Inhibition of epidermal growth factor receptor (EGFR) and the mechanistic target of rapamycin (mTOR) may have synergistic antitumor effects in high-grade glioma patients.

METHODS

We conducted a phase I/II study of the EGFR inhibitor erlotinib (150 mg/day) and the mTOR inhibitor temsirolimus. Patients initially received temsirolimus 50 mg weekly, and the dose adjusted based on toxicities. In the phase II component, the primary endpoint was 6-month progression-free survival (PFS6) among glioblastoma patients.

RESULTS

Twenty-two patients enrolled in phase I, 47 in phase II. Twelve phase I patients treated at the maximum tolerated dosage were included in the phase II cohort for analysis. The maximum tolerated dosage was 15 mg temsirolimus weekly with erlotinib 150 mg daily. Dose-limiting toxicities were rash and mucositis. Among 42 evaluable glioblastoma patients, 12 (29%) achieved stable disease, but there were no responses, and PFS6 was 13%. Among 16 anaplastic glioma patients, 1 (6%) achieved complete response, 1 (6%) partial response, and 2 (12.5%) stable disease, with PFS6 of 8%. Tumor levels of both drugs were low, and posttreatment tissue in 3 patients showed no reduction in the mTOR target phosphorylated (phospho-)S6(S235/236) but possible compensatory increase in phospho-Akt(S473). Presence of EGFR variant III, phospho-EGFR, and EGFR amplification did not correlate with survival, but patients with elevated phospho-extracellular signal-regulated kinase or reduced phosphatase and tensin homolog protein expression had decreased progression-free survival at 4 months.

CONCLUSION

Because of increased toxicity, the maximum tolerated dosage of temsirolimus in combination with erlotinib proved lower than expected. Insufficient tumor drug levels and redundant signaling pathways may partly explain the minimal antitumor activity noted.

LIN28 is involved in glioma carcinogenesis and predicts outcomes of glioblastoma multiforme patients

LIN28, an evolutionarily conversed RNA binding protein which can bind to the terminal loops of let-7 family microRNA precursors and block their processing to maturation, is highly expressed in several subsets of tumors that carry poor prognoses, such as ovarian carcinoma, hepatocellular carcinoma, colon carcinoma and germ cell carcinoma. However, there has been no study on the expression of LIN28 in glioma tissues or their importance as a prognostic predictor of glioma patients. This study aimed to examine the expression of LIN28 in glioma and correlate the results to patient outcome. We found that LIN28 expression was significantly higher in the group of patients with a poor prognosis compared to patients with a good prognosis by gene microarray. Log-rank analysis showed patients with higher LIN28 expression level in tumor had a shorter progression-free survival and overall survival times compared to those with lower LIN28 expression level. Similar results were also obtained from the tissue microarray analysis. Univariate and multivariate analyses showed high LIN28 expression was an independent prognostic factor for a shorter progression-free survival and overall survival in GBM patients. Furthermore in vitro experiments showed that down-regulation of LIN28 in U251 and U373 cells caused cell cycle arrest in the G1 phase, delayed cell proliferation, increased apoptosis, and resulted in fewer colonies compared to controls. Summarily, our data provides a potential target for cancer therapy as an approach to overcome the poor options currently available for GBM patients.

[Modern molecular approaches to diagnosis and treatment of high-grade brain gliomas]

The review analyzes the current state of the problem of diagnosis and therapy of high-grade gliomas on the basis of the most promising present-day approaches. The diagnostic and treatment perspectives of the molecular genetic analysis of glioblastoma markers located on the tumor cell surface are considered. Gene therapy and the use of dendritic cells and oncolytic viruses are considered as the most interesting approaches to therapy of high-grade gliomas.

A novel EGFR isoform confers increased invasiveness to cancer cells

As a validated therapeutic target in several human cancers, the EGF receptor (EGFR) provides a focus to gain deeper insights into cancer pathophysiology. In this study, we report the identification of a naturally occurring and widely expressed EGFR isoform termed EGFRvA, which substitutes a Ser/Thr-rich peptide for part of the carboxyl-terminal regulatory domain of the receptor. Intriguingly, EGFRvA expression relates more closely to histopathologic grade and poor prognosis in patients with glioma. Ectopic expression of EGFRvA in cancer cells conferred a higher invasive capacity than EGFR in vitro and in vivo. Mechanistically, EGFRvA stimulated expression of STAT3, which upregulated heparin-binding EGF (HB-EGF). Reciprocally, HB-EGF stimulated phosphorylation of EGFRvA at Y845 along with STAT3, generating a positive feedback loop that may reinforce invasive function. The significance of EGFRvA expression was reinforced by findings that it is attenuated by miR-542-5p, a microRNA that is a known tumor suppressor. Taken together, our findings define this newfound EGFR isoform as a key theranostic molecule.

Imaging EGFR and HER2 by PET and SPECT: a review

In an effort to discover a noninvasive method for predicting which cancer patients will benefit from therapy targeting the EGFR and HER2 proteins, a large body of the research has been conducted toward the development of PET and SPECT imaging agents, which selectively target these receptors. We provide a general overview of the advances made toward imaging EGFR and HER2, detailing the investigation of PET and SPECT imaging agents ranging in size from small molecules to monoclonal antibodies.

Correlation of Nrf2 and HIF-1α in glioblastoma and their relationships to clinicopathologic features and survival

OBJECTIVES

Glioblastoma (GB) is the most common, aggressive, and proliferative among all brain tumors. The prognosis of GB is still far from satisfactory currently, thus demanding great modification and enhancement, which may be acquired by the help of the molecular target therapy. Nuclear factor E2-related factor 2 (Nrf2), a pivotal transcriptional factor of cellular responses to oxidative stress, was observed to function remarkably in cancer pathobiology. In the current study, we analyzed the correlation between Nrf2 and Hypoxia-inducible factor-1alpha (HIF-1alpha) in GB, together with their association to the features and survival of clinicopathology.

METHODS

We examined the expression of Nrf2 and HIF-1alpha in 68 specimens of GB by tissue microarray and immunohistochemistry, and correlated this investigation to the outcome of GB patients.

RESULTS

Nrf2 and HIF-1alpha were overexpressed in GB tissues. There was significant correlation between the high level of Nrf2 and tumor necrosis on MRI and 1-year survival. There was significant correlation between HIF-1alpha level and Nrf2 status (r = 0·294, P = 0·015). Kaplan-Meier analysis showed that high Nrf2 expression was significantly associated with shorter overall survival (OS) (log-rank test, P = 0·006), and was identified as an independent prognostic factor in multivariate analysis (P = 0·034). HIF-1alpha was another independent factor for both OS and progression-free survival by Cox regression analysis (P = 0·048 and P = 0·032, respectively).

DISCUSSION

Mutual association between Nrf2 and HIF-1alpha was found in GB: higher Nrf2 expression and poorer outcome of GB patients. Nrf2 would therefore be a new molecular marker for the targeted treatment of GB.

Cells with intense EGFR staining and a high nuclear to cytoplasmic ratio are specific for infiltrative glioma: a useful marker in neuropathological practice

BACKGROUND

The differential diagnosis between infiltrative glioma (IG) and benign or curable glial lesions, such as gliosis, pilocytic astrocytoma, dysembryoplastic neuroepithelial tumor, ganglioglioma, or demyelinating disease, may be challenging for the pathologist because specific markers are lacking. Recently, we described a strong EGFR immunolabelling pattern in cells with a high nuclear to cytoplasmic ratio that enables the discrimination of low-grade IG from gliosis. The aim of this study was to extend our observation to high-grade glioma to assess whether EGFR expression pattern is of value in the discrimination of all IG from noninfiltrative glial lesions (NIG), including gliosis, benign tumors, and demyelinating disease.

METHODS

One hundred one IG and 58 NIG were compared for immunohistochemical expression of EGFR with use of an antibody that recognizes an epitope in the extracellular domain of both EGFRwt and EGFRvIII. Highly EGFR-positive cells with a high nuclear to cytoplasmic ratio were isolated and further characterized.

RESULTS

Cells with intense EGFR staining and a high nuclear to cytoplasmic ratio were significantly associated with the diagnosis of IG (P < .0001). The sensitivity and specificity of this staining pattern for the diagnosis of IG were 95% and 100%, respectively. EGFR expression was independent of IDH1 mutations and EGFR amplification. Finally, we showed that these particular cells displayed the phenotype and properties of glial progenitors and coexpressed CXCR4, a marker of invasiveness.

CONCLUSIONS

We demonstrate that cells with intense EGFR staining and a high nuclear to cytoplasmic ratio are specific criteria for the diagnosis of IG, irrespective of grade, histological subtype, and progression pathway, and their identification represents a tool to discriminate IG from benign or curable glial lesions.

Therapeutic targeting of EGFR-activated metabolic pathways in glioblastoma

INTRODUCTION

The highly divergent histological heterogeneities, aggressive invasion and extremely poor response to treatment make glioblastoma (GBM) one of the most lethal and difficult cancers in humans. Among key elements driving its behavior is epidermal growth factor receptor (EGFR), however, neither traditional therapy including neurosurgery, radiation, temozolomide, nor targeted EGFR therapeutics in clinic has generated promising results to date. Strategies are now focusing on blocking the downstream EGFR-activated metabolic pathways and the key phosphorylated kinases.

AREAS COVERED

Here, we review two major EGFR-activated downstream metabolic pathways including the PI3K/AKT/mTOR and RAS/RAF/MAPK pathways and their key phosphorylated kinase alterations in GBMs. This review also discusses potential pharmacological progress from bench work to clinical trials in order to evaluate specific inhibitors as well as therapeutics targeting PI3K and RAS signaling pathways.

EXPERT OPINION

Several factors impede clinical progress in targeting GBM, including the high rates of acquired resistance, heterogeneity within and across the tumors, complexity of signaling pathways and difficulty in traversing the blood-brain barrier (BBB). Substantial insight into genetic and molecular pathways and strategies to better tap the potential of these agents include rational combinatorial regimens and molecular phenotype-based patient enrichment, each of which will undoubtedly generate new therapeutic approaches to combat these devastating disabilities in the near future.

Epidermal growth factor receptor variant type III markedly accelerates angiogenesis and tumor growth via inducing c-myc mediated angiopoietin-like 4 expression in malignant glioma

Background

Expression of the constitutively activated mutant EGFR variant III (EGFRvIII), the most common mutation in glioblastoma multiforme (GBMs), has been clinically correlated with tumor proliferation, invasion, and angiogenesis. In this study, we examined the role of EGFRvIII on the tumor microenvironment, especially on angiogenesis.

Methods

To study the role of EGFRvIII in tumor angiogenesis, we prepared LN229 glioblastoma transfected with enhanced green fluorescent protein (EGFP), wild-type EGFR, or EGFRvIII (LN229-WT or -vIII), and examined tumor growth and microvessel density in the tumors. Additionally, the potential angiogenic factors were identified by real-time PCR analysis, and the functions in LN229-vIII cells were examined.

Results

LN229-vIII cells showed more aggressive tumor growth and higher vascularity as compared to LN229-WT cells in vivo, although there was no significant difference in the cell growth rates in vitro. We next investigated the expression of 60 angiogenesis-related factors to clarify the mechanisms underlying the difference in vascularity between tumor xenografts of LN229-vIII and LN229-WT. We found that the mRNA and protein expressions of angiopoietin-like 4 (Angptl4), a secreted protein involved in angiogenesis and metabolism regulation, were significantly induced by EGFRvIII overexpression, both in vitro and in vivo. Constitutive knockdown of Angptl4 in LN229-vIII using shRNA significantly decreased the microvessel density in the tumor xenografts and suppressed tumor growth. To clarify the regulatory mechanisms of Angptl4 by EGFRvIII, we analyzed the signaling pathways and transcription factors by pharmacological inhibition and RNA interference. U0126, an ERK signal inhibitor dramatically suppressed Angptl4 expression. The transcription factor c-Myc, which is regulated by ERK, was activated in the LN229-vIII cells and knockdown of c-Myc using siRNA also attenuated Angptl4 expression in the LN229-vIII cells. Furthermore, chromatin immunoprecipitation (ChIP) assay revealed increased recruitment of c-Myc to the promoter region of Angptl4 in the LN229-vIII cells.

Conclusions

In summary, we demonstrated that EGFRvIII induces Angptl4 expression through the ERK/c-Myc pathway and promotes tumor angiogenesis in malignant gliomas.

Expression of p53, epidermal growth factor receptor, Ki-67 and O6-methylguanine-DNA methyltransferase in human gliomas

The present study aimed to evaluate the expression of p53, Ki-67, epidermal growth factor receptor (EGFR) and O⁶-methylguanine-DNA methyltransferase (MGMT), and to analyze the correlation between their expression and the histological grade of the tumors in 152 patients with gliomas. The tumors were classified according to the recommendations of the World Health Organization (WHO; 2007) into grade I (n=9), grade II (n=56), grade III (n=52) and grade IV (n=35). The expression of p53, Ki-67, EGFR and MGMT was analyzed using immunohistochemistry. The frequency of p53 immunopositivity was significantly lower in grade I gliomas than in grades II, III and IV. The frequency of EGFR immunopositivity was significantly higher in grade III and IV gliomas compared with grades I and II. The mean Ki-67 labelling index (LI) significantly increased in the higher glioma grades. The expression of MGMT in grade I and II tumors was not significantly different from that of grade III and IV tumors. The present data indicate that the expression of EGFR and Ki-67 is significantly correlated with the histological grade of the glioma, but that the expression of p53 and MGMT is not associated with the tumor grade.

Combined RNAi-mediated suppression of Rictor and EGFR resulted in complete tumor regression in an orthotopic glioblastoma tumor model

The PI3K/AKT/mTOR pathway is commonly over activated in glioblastoma (GBM), and Rictor was shown to be an important regulator downstream of this pathway. EGFR overexpression is also frequently found in GBM tumors, and both EGFR and Rictor are associated with increased proliferation, invasion, metastasis and poor prognosis. This research evaluated in vitro and in vivo whether the combined silencing of EGFR and Rictor would result in therapeutic benefits. The therapeutic potential of targeting these proteins in combination with conventional agents with proven activity in GBM patients was also assessed. In vitro validation studies were carried out using siRNA-based gene silencing methods in a panel of three commercially available human GBM cell lines, including two PTEN mutant lines (U251MG and U118MG) and one PTEN-wild type line (LN229). The impact of EGFR and/or Rictor silencing on cell migration and sensitivity to chemotherapeutic drugs in vitro was determined. In vivo validation of these studies was focused on EGFR and/or Rictor silencing achieved using doxycycline-inducible shRNA-expressing U251MG cells implanted orthotopically in Rag2M mice brains. Target silencing, tumor size and tumor cell proliferation were assessed by quantification of immunohistofluorescence-stained markers. siRNA-mediated silencing of EGFR and Rictor reduced U251MG cell migration and increased sensitivity of the cells to irinotecan, temozolomide and vincristine. In LN229, co-silencing of EGFR and Rictor resulted in reduced cell migration, and increased sensitivity to vincristine and temozolomide. In U118MG, silencing of Rictor alone was sufficient to increase this line’s sensitivity to vincristine and temozolomide. In vivo, while the silencing of EGFR or Rictor alone had no significant effect on U251MG tumor growth, silencing of EGFR and Rictor together resulted in a complete eradication of tumors. These data suggest that the combined silencing of EGFR and Rictor should be an effective means of treating GBM.

Array CGH in brain tumors

Alterations in the copy number of the cancer genome are frequently observed in brain tumors especially gliomas. Some pertinent examples include amplification of the EGFR locus in chromosome 7p and loss of the PTEN locus in 10q in glioblastoma. Meningiomas are often associated with loss of the NF2 locus in 22q. Array CGH or aCGH probes provide a reliable, consistent, and economical method of profiling genome-wide copy number alterations (CNAs) of cancer specimens at fairly robust resolution. This has allowed for the systematic assessment of brain tumors for recurrent genomic CNAs. In addition, recent technical advancements have increased the robustness of this technique to accommodate DNA derived from formalin-fixed paraffin-embedded (FFPE) tissue. Lastly, novel technologies such as next-generation sequencing and multiplex digital gene counting technology such as NanoString will expand the -repertoire of techniques for assessing CNAs in brain tumors.

Epidermal growth factor receptor is related to poor survival in glioblastomas: single-institution experience

PURPOSE

There are conflicting results surrounding the prognostic significance of epidermal growth factor receptor (EGFR) status in glioblastoma (GBM) patients. Accordingly, we attempted to assess the influence of EGFR expression on the survival of GBM patients receiving postoperative radiotherapy.

MATERIALS AND METHODS

Thirty three GBM patients who had received surgery and postoperative radiotherapy at our institute, between March 1997 and February 2006, were included. The evaluation of EGFR expression with immunohistochemistry was available for 30 patients. Kaplan-Meier survival analysis and Cox regression were used for statistical analysis.

RESULTS

EGFR was expressed in 23 patients (76.7%), and not expressed in seven (23.3%). Survival in EGFR expressing GBM patients was significantly less than that in non-expressing patients (median survival: 12.5 versus 17.5 months, p=0.013). Patients who received more than 60 Gy showed improved survival over those who received up to 60 Gy (median survival: 17.0 versus 9.0 months, p=0.000). Negative EGFR expression and a higher radiation dose were significantly correlated with improved survival on multivariate analysis. Survival rates showed no differences according to age, sex, and surgical extent.

CONCLUSION

The expression of EGFR demonstrated a significantly deleterious effect on the survival of GBM patients. Therefore, approaches targeting EGFR should be considered in potential treatment methods for GBM patients, in addition to current management strategies.

Overexpression of Golgi phosphoprotein-3 (GOLPH3) in glioblastoma multiforme is associated with worse prognosis

Golgi phosphoprotein-3 (GOLPH3), an important protein in mammalian target of rapamycin (mTOR) signaling, is overexpressed in and correlates with the pathological grade of glioma. However, the potential correlation between GOLPH3 and clinical outcome in patients with glioblastoma multiforme (GBM) remains unknown. In this study, we examined GOLPH3 expression in GBM by tissue microarray and correlated this measure to patient outcome. GOLPH3 expression in tumor tissue from 97 primary GBM patients was examined by tissue microarray and immunohistochemistry. Potential effects of GOLPH3 on tumor growth were also examined in representative cell lines (U251 and U87) by downregulating GOLPH3 with RNA interference. For this cohort, the median overall survival (OS) was 12 months [95 % confidence interval (CI): 10.31-13.69 months], and the median progression-free survival (PFS) was 10 months (95 % CI: 7.33-12.67 months). Tissue microarray analysis revealed high GOLPH3 expression in 40 patients (40/97, 41.2 %) and low GOLPH3 expression in the remaining 57 patients (57/97, 58.8 %). Log-rank test showed that patients with low GOLPH3 expression had significantly longer median OS (15 versus 10 months in patients with high GOLPH3 expression, p = 0.009) and median PFS (12 versus 7 months, p = 0.015). Univariate and Cox analysis indicated that GOLPH3 was an independent prognostic factor for OS and PFS. In in vitro experiments, GOLPH3 downregulation by small interfering RNA (siRNA) suppressed proliferation and clonogenic growth in cultured cell lines. These findings demonstrate that high GOLPH3 expression is associated with poor outcome of GBM patients.

Overexpression of CARMA3 in non-small-cell lung cancer is linked for tumor progression

We aimed to investigate the clinical significance of the expression of novel scaffold protein CARMA3 in non-small-cell lung cancer (NSCLC) and the biological function of CARMA3 in NSCLC cell lines. We observed moderate to high CARMA3 staining in 68.8% of 141 NSCLC specimens compared to corresponding normal tissues. The overexpression of CARMA3 was significantly correlated with TNM stage (P = 0.022) and tumor status (P = 0.013). CARMA3 upregulation also correlated with a shorter survival rate of patients of nodal status N0 (P = 0.042)as well as the expression of epidermal growth factor receptor (EGFR) (P = 0.009). In EGFR mutation positive cases, CARMA3 expression was much higher (87.5%) compared to non-mutation cases (66.1%). In addition, we observed that knockdown of CARMA3 inhibits tumor cell proliferation and invasion, and induces cell cycle arrest at the boundary between the G1 and S phase. We further demonstrated a direct link between CARMA3 and NF-κB activation. The change of biological behavior in CARMA3 knockdown cells may be NF-κB-related. Our findings demonstrated, for the first time, that CARMA3 was overexpressed in NSCLC and correlated with lung cancer progression, EGFR expression, and EGFR mutation. CARMA3 could serve as a potential companion drug target, along with NF-kB and EGFR in EGFR-mutant lung cancers.

Insights into pediatric diffuse intrinsic pontine glioma through proteomic analysis of cerebrospinal fluid

Diffuse intrinsic pontine glioma (DIPG) is a leading cause of brain tumor-related death in children. DIPG is not surgically resectable, resulting in a paucity of tissue available for molecular studies. As such, tumor biology is poorly understood, and, currently, there are no effective treatments. In the absence of frozen tumor specimens, body fluids--such as cerebrospinal fluid (CSF), serum, and urine--can serve as more readily accessible vehicles for detecting tumor-secreted proteins. We analyzed a total of 76 specimens, including CSF, serum, urine, and normal and tumor brainstem tissue. Protein profiling of CSF from patients with DIPG was generated by mass spectrometry using an LTQ-Orbitrap-XL and database search using the Sequest algorithm. Quantitative and statistical analyses were performed with ProteoIQ and Partek Genomics Suite. A total of 528 unique proteins were identified, 71% of which are known secreted proteins. CSF proteomic analysis revealed selective upregulation of Cyclophillin A (CypA) and dimethylarginase 1 (DDAH1) in DIPG (n = 10), compared with controls (n = 4). Protein expression was further validated with Western blot analysis and immunohistochemical assays using CSF, brain tissue, serum, and urine from DIPG and control specimens. Immunohistochemical staining showed selective upregulation of secreted but not cytosolic CypA and DDAH1 in patients with DIPG. In this study, we present the first comprehensive protein profile of CSF specimens from patients with DIPG to demonstrate selective expression of tumor proteins potentially involved in brainstem gliomagenesis. Detection of secreted CypA and DDAH1 in serum and urine has potential clinical application, with implications for assessing treatment response and detecting tumor recurrence in patients with DIPG.

Towards personalized therapy for patients with glioblastoma

Combined therapy with temozolomide and radiotherapy is a standard treatment and improves the survival for patients with newly diagnosed glioblastoma. However, the prognosis remains poor, with a median survival time of 12-15 months. Currently, several clinical trials of dose-dense temozolomide regimen or molecular-targeting therapies have been performed to overcome the resistance of glioblastoma. In these therapies, rational prognostic biomarkers have also been investigated to predict their outcome and response to treatment. This advanced understanding of the biological markers can help to develop personalized therapies for glioblastoma patients. Generally, due to a reduced tolerance, elderly patients do not seem to benefit from intensive treatment. This population needs individual treatments depended on their age or performance status. In this article, we review the recent studies that can provide personalized therapy for glioblastoma, based on molecular tumor profiling or patients' physical status.

Molecular pathology of lung cancer: key to personalized medicine

The majority of lung adenocarcinoma patients with epidermal growth factor receptor- (EGFR) mutated or EML4-ALK rearrangement-positive tumors are sensitive to tyrosine kinase inhibitors. Both primary and acquired resistance in a significant number of those patients to these therapies remains a major clinical problem. The specific molecular mechanisms associated with tyrosine kinase inhibitor resistance are not fully understood. Clinicopathological observations suggest that molecular alterations involving so-called 'driver mutations' could be used as markers that aid in the selection of patients most likely to benefit from targeted therapies. In this review, we summarize recent developments involving the specific molecular mechanisms and markers that have been associated with primary and acquired resistance to EGFR-targeted therapy in lung adenocarcinomas. Understanding these mechanisms may provide new treatment avenues and improve current treatment algorithms.

Sendai virus-based liposomes enable targeted cytosolic delivery of nanoparticles in brain tumor-derived cells

Background

Nanotechnology-based bioassays that detect the presence and/or absence of a combination of cell markers are increasingly used to identify stem or progenitor cells, assess cell heterogeneity, and evaluate tumor malignancy and/or chemoresistance. Delivery methods that enable nanoparticles to rapidly detect emerging, intracellular markers within cell clusters of biopsies will greatly aid in tumor characterization, analysis of functional state and development of treatment regimens.

Results

Experiments utilized the Sendai virus to achieve in vitro, cytosolic delivery of Quantum dots in cells cultured from Human brain tumors. Using fluorescence microscopy and Transmission Electron Microscopy, in vitro experiments illustrated that these virus-based liposomes decreased the amount of non-specifically endocytosed nanoparticles by 50% in the Human glioblastoma and medulloblastoma samples studied. Significantly, virus-based liposome delivery also facilitated targeted binding of Quantum dots to cytosolic Epidermal Growth Factor Receptor within cultured cells, focal to the early detection and characterization of malignant brain tumors.

Conclusions

These findings are the first to utilize the Sendai virus to achieve cytosolic, targeted intracellular binding of Qdots within Human brain tumor cells. The results are significant to the continued applicability of nanoparticles used for the molecular labeling of cancer cells to determine tumor heterogeneity, grade, and chemotherapeutic resistivity.

Overcoming molecular mechanisms of resistance to first-generation epidermal growth factor receptor tyrosine kinase inhibitors

The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib have provided substantial benefits to patients with advanced non-small cell lung cancer (NSCLC). However resistance to these agents has emerged as a significant clinical issue; most patients who initially respond to treatment eventually experience relapse. The mechanisms underlying gefitinib and erlotinib resistance are multifactorial and several have been described. Clearly there is a need for novel and more effective therapies that can overcome resistance to the currently available TKIs. Several agents are in clinical development, including irreversible EGFR TKIs, inhibitors of the MET pathway, and others. In this review we discuss the various underlying mechanisms of gefitinib and erlotinib resistance and highlight the agents currently in clinical development that may have potential for overcoming this resistance.

Gene-protein correlation in single cells

We present a novel methodology combining traditional fluorescent in situ hybridization with an in situ protein detection technology called proximity ligation assay. This method has potential to perform a detailed analysis of the relationship between gene status and corresponding protein expression in cells and tissues. We demonstrate that the fluorescent in situ gene protein assay methodology is capable of resolving gene and protein patterns simultaneously on a cell-by-cell basis.

Chemopreventive effect of a mixture of Chinese Herbs (antitumor B) on chemically induced oral carcinogenesis

In this study, we evaluated chemopreventive efficacy of Antitumor B, a Chinese herbal mixture of six plants (Sophora tonkinensis, Polygonum bistorta, Prunella vulgaris, Sonchus arvensis L., Dictamnus dasycarpus, and Dioscorea bulbifera) on the development of 4-nitroquinoline-1-oxide (4NQO) induced oral squamous cell carcinomas in A/J mice. Antitumor B, delivered through diet, inhibited 4NQO-induced oral cancer development by 59.19%. The reduction of cell proliferation appears to be associated with efficacy of Antitumor B against 4NQO-induced oral cancer in A/J mice. The expression of epidermal growth factor receptor (EGFR) and phosphorylated EGFR (Tyr1173) were down-regulated by Antitumor B. Tissue distribution of Antitumor B was determined using obacunone, matrine, and maackiain as marker chemicals. We found significant amounts of obacunone, matrine, and maackiain in the blood after 1-wk treatment. The concentrations of these three compounds did not increase further at 18  wk, suggesting that plasma concentrations had reached a steady-state level at 1  wk. There was no significant body weight loss and there was no other obvious sign of toxicity in Antitumor B-treated mice. These results suggest that Antitumor B is a promising agent for human oral cancer chemoprevention.

Cetuximab induces mitochondrial translocalization of EGFRvIII, but not EGFR: involvement of mitochondria in tumor drug resistance?

Dysregulation of growth factor receptors such as the epidermal growth factor receptor (EGFR) and of its truncated form EGFRvIII is frequently found in human tumors. EGFRvIII is a promising target for selective molecular tumor therapy because it is exclusively expressed by tumor cells. Cetuximab/Erbitux is a monoclonal antibody which targets EGFR and EGFRvIII. The effects of cetuximab on EGFRvIII but still the exact function and mechanism of cetuximab in relation to EGFR and EGFRvIII are incompletely understood. Therefore, we investigated the influence of cetuximab on EGFRvIII signaling and cellular survival. We found that cetuximab leads to increased internalization of EGFRvIII in NR6M cells but is unable to inhibit neither the activation of EGFRvIII nor its downstream signaling pathways. Incubation with cetuximab also did not alter the survival and proliferation of EGFRvIII-expressing cells. However, it caused increased mitochondrial activity and an increase in co-localization of EGFRvIII with mitochondria. These results demonstrate that interaction of EGFRvIII with mitochondria could play a role in survival of cetuximab-treated NR6M cells. Thus, a role of mitochondria in resistance to cetuximab has to be considered.

Downregulation of GRIM-19 promotes growth and migration of human glioma cells

It has become increasingly clear that there are notable parallels between normal development and tumorigenesis. Glioma is a classic model that links between tumorigenesis and development. We evaluated the expression of GRIM-19, a novel gene essential for normal development, in various grades of gliomas and several human glioma cell lines. We showed that GRIM-19 mRNA and protein expression were markedly lower in gliomas than in control brain tissues and negatively correlated with the malignancy of gliomas. Downregulation of GRIM-19 in glioma cells significantly enhanced cell proliferation and migration, whereas overexpression of GRIM-19 showed the opposite effects. We also showed that the activation of signal transducer and activator of transcription 3 (STAT3) and the expression of many STAT3-dependent genes were regulated by the expression of GRIM-19. In addition, GRIM-19 exerted its role probably through the non-STAT3 signaling pathway. Collectively, our data suggest that most gliomas expressed GRIM-19 at low levels, which may play a major role in tumorigenesis in the brain.

Detailed characterization of alterations of chromosomes 7, 9, and 10 in glioblastomas as assessed by single-nucleotide polymorphism arrays

Glioblastomas are cytogenetically heterogeneous tumors that frequently display alterations of chromosomes 7, 9p, and 10q. We used high-density (500K) single-nucleotide polymorphism arrays to investigate genome-wide copy number alterations and loss of heterozygosity in 35 primary glioblastomas. We focused on the identification and detailed characterization of alterations involving the most frequently altered chromosomes (chromosomes 7, 9, and 10), the identification of distinct prognostic subgroups of glioblastomas based on the cytogenetic patterns of alteration for these chromosomes, and validation of their prognostic impact in a larger series of tumors from public databases. Gains of chromosome 7 (97%), with or without epidermal growth factor receptor (EGFR) amplification, and losses of chromosomes 9p (83%) and 10 (91%) were the most frequent alterations. Such alterations defined five different cytogenetic groups with a significant effect on patient survival; notably, EGFR amplification (29%) was associated with a better survival among older patients, as confirmed by multivariate analysis of a larger series of glioblastomas from the literature. In addition, our results provide further evidence about the relevance of other genes (eg, EGFR, CDKN2A/B, MTAP) in the pathogenesis of glioblastomas. Altogether, our results confirm the cytogenetic heterogeneity of glioblastomas and suggest that their stratification based on combined assessment of cytogenetic alterations involving chromosomes 7, 9, and 10 may contribute to the prognostic evaluation of glioblastomas.

Innovative Therapies against Human Glioblastoma Multiforme

Glioblastoma multiforme is the most invasive and aggressive brain tumor in humans, and despite the latest chemical and radiative therapeutic approaches, it is still scarcely sensitive to these treatments and is generally considered an incurable disease. This paper will focus on the latest approaches to the treatment of this cancer, including the new chemicals such as proautophagic drugs and kinases inhibitors, and differentiating agents. In this field, there have been opening new perspectives as the discovery of possible specific targets such as the EGFRvIII, a truncated form of the EGF receptor. Antibodies against these targets can be used as proapoptotic agents and as possible carriers for chemicals, drugs, radioisotopes, and toxins. In this paper, we review the possible mechanism of action of these therapies, with particular attention to the combined use of toxic substances (for example, immunotoxins) and antiproliferative/differentiating compounds (i.e., ATRA, PPARγ agonists). All these aspects will be discussed in the view of progress clinical trials and of possible new approaches for directed drug formulations.

EGFR-mutated lung cancer: a paradigm of molecular oncology

The development of EGFR tyrosine kinase inhibitors for clinical use in non-small cell lung cancer and the subsequent discovery of activating EGFR mutations have led to an explosion of knowledge in the fields of EGFR biology, targeted therapeutics and lung cancer research. EGFR-mutated adenocarcinoma of the lung has clearly emerged as a unique clinical entity necessitating the routine introduction of molecular diagnostics into our current diagnostic algorithms and leading to the evidence-based preferential usage of EGFR-targeted agents for patients with EGFR-mutant lung cancers. This review will summarize our current understanding of the functional role of activating mutations, key downstream signaling pathways and regulatory mechanisms, pivotal primary and acquired resistance mechanisms, structure-function relationships and ultimately the incorporation of molecular diagnostics and small molecule EGFR tyrosine kinase inhibitors into our current treatment paradigms.

Molecular heterogeneity in glioblastoma: therapeutic opportunities and challenges

Glioblastoma (GBM) has been recognized as a clinical and pathologic entity for more than a century. Throughout its history, its cells of origin have been in question. Its behavior is aggressive and despite decades of effort, median survival is just beginning to improve. Surgical techniques and radiotherapy schemas continue to be refined, but the most recent progress has been achieved through improved medical therapies. These are the result of both pharmacological advances and a deeper understanding of the biological characteristics of GBM. Due to a combination of its complex phenotype and organ-specific clinical manifestations, efforts to refine GBM treatment with targeted therapies largely have been frustrated. In this review, we discuss recent attempts to exploit new molecular insights, consider the reasons for slow progress in developing better treatments, and examine future therapeutic options.

Molecular mechanisms of epidermal growth factor receptor overexpression in patients with cervical cancer

The epidermal growth factor receptor is overexpressed in 70-90% of cervical cancers. Previously, we have shown that epidermal growth factor receptor overexpression independently predicts poor prognosis in cervical cancer patients, which makes it a potential therapeutic target. The aim of this study was to systematically analyze the molecular mechanism leading to epidermal growth factor receptor overexpression in cervical cancer. All experiments were performed on archival paraffin-embedded material. In 166 cervical cancer patients, cytoplasmic, membrane and phosphorylated epidermal growth factor receptor protein expression were studied in association with patient survival. Membrane epidermal growth factor receptor overexpression was associated with poor disease-specific survival (P=0.027). This association was particularly present in human papillomavirus 16-positive patients (P=0.029). We analyzed whether epidermal growth factor receptor overexpression was caused by gene amplification using fluorescence in situ hybridization. Epidermal growth factor receptor gene copy number was linked to chromosome 7 ploidy, as no gene amplification could be detected when corrected for chromosome 7 centromeric signals. Chromosome 7 aneuploidy was associated with membrane epidermal growth factor receptor overexpression (P=0.013). Additional mutation analysis was performed by sequencing pure, flow-sorted tumor cells, but no mutations were detected. Furthermore, human papillomavirus 16 E5 and E6 oncogene mRNA expression was measured, using quantitative real-time polymerase chain reaction, to determine the association between the human papillomavirus and epidermal growth factor receptor overexpression. High human papillomavirus 16 E5 and E6 mRNA expression were associated with decreased survival (P=0.045 and 0.047, respectively). High human papillomavirus 16 E6 mRNA expression was associated with membrane epidermal growth factor receptor overexpression (P=0.013). This is the first study performed on cancer patient material showing that chromosome 7 aneuploidy and high human papillomavirus 16 E6 mRNA expression lead to membrane epidermal growth factor receptor overexpression in cervical cancer.

HMGN5: a potential oncogene in gliomas

Gliomas are the most common primary brain tumors in the central nervous system and a leading cause of tumor-related death. High-mobility group nucleosome binding domain 5 (HMGN5/NSBP1), which is highly expressed in breast cancer and in hormone-induced mouse uterine adenocarcinoma, acts as a potential oncogene in gliomas. In this study, the role of HMGN5 in the proliferation of human glioma cells was investigated by lentivirus-mediated RNA interference (RNAi). The decrease in HMGN5 expression in human glioma U251 and U87 cells caused cell cycle arrest in the G1 phase and a delay in cell proliferation, as well as resulting in more apoptosis and an inhibition of clonogenic growth in soft agar in U251 cells; these results suggest that HMGN5 is required for tumorigenesis in vitro. Furthermore, HMGN5 was highly expressed in both high-grade and low-grade glioma tissue samples compared with normal brain tissues. Collectively, our data suggest that HMGN5 may play a critical role in the development of gliomas.

Prognostic significance of kappaB-Ras1 expression in gliomas

Nuclear factor (NF)-kappa-B is a pleiotropic transcriptional regulator that plays important roles in cell differentiation, growth, tumorigenesis, and apoptosis. Constitutive NF-kappa-B is overexpressed and activated in various tumors, including gliomas. Here, we investigated the expression of NF-kappa-B inhibitor interacting ras-like protein 1 (κB-Ras1), which is one of the most important negative modulators of NF-kappa-B, and a well-known proliferation biomarker survivin protein. We performed immunohistochemistry and western blot analysis on 154 glioma specimens and 3 non-neoplastic brain parenchyma specimens. Immunohistochemistry showed a strong-to-weak range of κB-Ras1 staining with increasing pathologic grade of glioma (P = 0.000). Immunoreactivity scores of κB-Ras1 were 8.15 ± 0.72 in non-neoplastic brain parenchyma, 5.00 ± 0.29 in low-grade gliomas, 3.89 ± 0.30 in anaplasia astrocytomas, and 2.78 ± 0.25 in glioblastomas. In contrast, the immunoreactivity of survivin increased with pathological grade in gliomas. The immunohistochemical data were in line with the results from western blot analysis. Moreover, a non-parametric analysis revealed that the attenuated κB-Ras1 expression was correlated with elevated survivin expression, large tumor diameter, frequent intra-tumor necrosis, and worse overall survival. These results indicated that κB-Ras1 was down-regulated in gliomas compared to non-neoplastic brain parenchyma, and the expression was even lower in glioblastomas. In addition, multivariate analysis showed that κB-Ras1 expression and intra-tumor necrosis were two important prognostic factors identified by the Cox proportional hazards model. Taken together, our study suggests that glioma patients with lower κB-Ras1 expression have a worse prognosis, which is partly due to NF-kappa-B pathway-mediated aberrant proliferation of tumor cells.