Epidermal growth factor receptor, protein kinase B/Akt, and glioma response to erlotinib

Application of EGFR-TKIs in brain tumors, a breakthrough in future?

Brain tumors, both primary and secondary, represent a significant clinical challenge due to their high mortality and limited treatment options. Primary brain tumors, such as gliomas and meningiomas, and brain metastases from cancers such as non-small cell lung cancer and breast cancer require innovative therapeutic strategies. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR -TKIs) have emerged as a promising treatment option, particularly for tumors harboring EGFR mutations. This review examines the use of EGFR-TKIs in brain tumors, highlighting both laboratory and clinical research findings. In primary brain tumors and brain metastases, EGFR-TKIs have shown potential in controlling tumor growth and improving patient outcomes. Advanced applications, such as nano-formulated EGFR-TKIs and combination therapies with other pathway inhibitors, are being investigated to improve efficacy and overcome resistance. Challenges such as treatment-related events, resistance mechanisms and blood-brain barrier penetration remain significant hurdles. Addressing tumor heterogeneity through personalized medicine approaches is critical to optimizing EGFR-TKI therapies. This review highlights the need for continued research to refine these therapies and improve survival for patients with brain tumors.

Opportunities and Challenges of Small Molecule Inhibitors in Glioblastoma Treatment: Lessons Learned from Clinical Trials

Glioblastoma (GBM) is the most prevalent central nervous system tumour (CNS). Patients with GBM have a dismal prognosis of 15 months, despite an intensive treatment schedule consisting of surgery, chemoradiation and concurrent chemotherapy. In the last decades, many trials have been performed investigating small molecule inhibitors, which target specific genes involved in tumorigenesis. So far, these trials have been unsuccessful, and standard of care for GBM patients has remained the same since 2005. This review gives an overview of trials investigating small molecule inhibitors on their own, combined with chemotherapy or other small molecule inhibitors. We discuss possible resistance mechanisms in GBM, focussing on intra- and intertumoral heterogeneity, bypass mechanisms and the influence of the tumour microenvironment. Moreover, we emphasise how combining inhibitors can help overcome these resistance mechanisms. We also address strategies for improving trial outcomes through modifications to their design. In summary, this review aims to elucidate different resistance mechanisms against small molecule inhibitors, highlighting their significance in the search for novel therapeutic combinations to improve the overall survival of GBM patients.

Analysis of IDH and EGFR as biomarkers in glioblastoma multiforme: A case-control study

Background

Glioblastoma multiforme (GBM) is a very aggressive primary central nervous system (CNS) tumor with limited therapeutic options and poor prognosis. This study aimed to analyze the association between single nucleotide polymorphisms (SNPs), including IDH1 rs121913500C > T, IDH2 rs11540478G > A, and EGFR rs1468727C > T, and their association on the risk and overall survival of GBM patients in Jordan.

Methods

Using a case-control study design involving 63 GBM patients and 226 healthy controls was conducted at King Abdullah University Hospital in Jordan. DNA extraction was performed using formalin-fixed and paraffin-embedded tissue for GBM samples and blood samples for controls. SNPs analysis was performed using the Sequenom iPLEX assay sequencing technique. Survival outcomes were assessed using Cox models and hazard ratios (HR), and single-cell RNA (scRNA) analysis was performed from GSE70630.

Results

The study showed a significant association between genotype frequency in GBM cases and controls for specific SNPs, including IDH1 rs121913500C > T, and EGFR rs1468727C > T. The G/G genotype of rs11540478 (IDH2) was associated with better prognostic outcomes in GBM patients. The scRNA analysis demonstrated the differential expression of IDH1, IDH2, and EGFR in GBM, with enrichment in central carbon metabolism in cancer.

Conclusion

Our findings suggest that SNPs, particularly in IDH1 and IDH2 genes and EGFR, may serve as diagnostic and prognostic biomarkers for GBM. While the study underscores the clinical relevance of these genetic variants, further investigations with larger and more diverse populations are essential to validate and extend these associations.

Strategies to Improve Drug Delivery Across the Blood-Brain Barrier for Glioblastoma

PURPOSE OF REVIEW

Glioblastoma remains resistant to most conventional treatments. Despite scientific advances in the past three decades, there has been a dearth of effective new treatments. New approaches to drug delivery and clinical trial design are needed.

RECENT FINDINGS

We discuss how the blood-brain barrier and tumor microenvironment pose challenges for development of effective therapies for glioblastoma. Next, we discuss treatments in development that aim to overcome these barriers, including novel drug designs such as nanoparticles and antibody-drug conjugates, novel methods of drug delivery, including convection-enhanced and intra-arterial delivery, and novel methods to enhance drug penetration, such as blood-brain barrier disruption by focused ultrasound and laser interstitial thermal therapy. Lastly, we address future opportunities, positing combination therapy as the best strategy for effective treatment, neoadjuvant and window-of-opportunity approaches to simultaneously enhance therapeutic effectiveness with interrogation of on-treatment biologic endpoints, and adaptive platform and basket trials as imperative for future trial design. New approaches to GBM treatment should account for the blood-brain barrier and immunosuppression by improving drug delivery, combining treatments, and integrating novel clinical trial designs.

An Overview of EGFR Mechanisms and Their Implications in Targeted Therapies for Glioblastoma

Despite all of the progress in understanding its molecular biology and pathogenesis, glioblastoma (GBM) is one of the most aggressive types of cancers, and without an efficient treatment modality at the moment, it remains largely incurable. Nowadays, one of the most frequently studied molecules with important implications in the pathogenesis of the classical subtype of GBM is the epidermal growth factor receptor (EGFR). Although many clinical trials aiming to study EGFR targeted therapies have been performed, none of them have reported promising clinical results when used in glioma patients. The resistance of GBM to these therapies was proven to be both acquired and innate, and it seems to be influenced by a cumulus of factors such as ineffective blood-brain barrier penetration, mutations, heterogeneity and compensatory signaling pathways. Recently, it was shown that EGFR possesses kinase-independent (KID) pro-survival functions in cancer cells. It seems imperative to understand how the EGFR signaling pathways function and how they interconnect with other pathways. Furthermore, it is important to identify the mechanisms of drug resistance and to develop better tailored therapeutic agents.

Genomic and Epigenomic Features of Glioblastoma Multiforme and its Biomarkers

Glioblastoma multiforme is a serious and life-threatening tumor of central nervous system, characterized by aggressive behavior, poor prognosis, and low survival rate. Despite of the availability of aggressive antitumor therapeutic regimen for glioblastoma (radiotherapy followed by chemotherapeutic dose), recovery rate, and patients' survival ratio is attributed to the lack of selectivity of therapeutic drugs and less advancement in cancer therapeutics over last decade. Moreover, tools employed in conventional diagnosis of glioblastoma are more invasive and painful, making the process excruciating for the patients. These challenges urge for the need of novel biomarkers for diagnosis, prognosis, and prediction purpose with less invasiveness and more patient compliance. This article will explore the genetic biomarkers isocitrate dehydrogenase mutation, MGMT mutations, and EGFR that can be deployed as an analytical tool in diagnosis of disease and prognosis of a therapeutic course. The review also highlights the importance of employing novel microRNAs as prognostic biomarkers. Recent clinical advancements to treat GBM and to prevent relapse of the disease are also discussed in this article in the hope of finding a robust and effective method to treat GBM.

Luteolin enhances erlotinib’s cell proliferation inhibitory and apoptotic effects in glioblastoma cell lines

The epidermal growth factor (EGFR) receptor is frequently overexpressed in glioblastoma multiforme IV (GBM). Increased expression of EGFR leads to increased proliferation, decreased apoptosis, and increased resistance to chemotherapeutic agents. A small molecule called erlotinib inhibits EGFR receptors by binding to their adenosine triphosphate (ATP) binding sites. It is FDA approved to treat a variety of EGFR-mediated cancers. Several clinical trials have explored a combination of erlotinib with other agents to treat glioblastoma since it is believed that erlotinib would benefit patients with GBM with EGFR mutations or expression. Luteolin, a natural flavonoid, inhibits cell growth and induces apoptosis in cancer cells. We investigated the combined effects of erlotinib and luteolin on proliferation and apoptosis on glioblastoma cell lines overexpressing EGFR or glioma cells expressing truncated EGFR (ΔEGFR). In a concentration-dependent fashion, the combination of luteolin and erlotinib reduced cell proliferation (p < 0.05) and induced apoptosis by cleaving PARP and increasing caspase expression. In addition, the combination of luteolin and erlotinib reduced the phosphorylation of downstream EGFR cell signaling molecules such as Akt, NF kappa B, and STAT3 in a concentration-dependent manner. These findings suggest that combining luteolin with erlotinib offers a potential treatment strategy for glioblastoma multiforme IV.

Cancer cell heterogeneity & plasticity in glioblastoma and brain tumors

Brain tumors remain one of the most difficult tumors to treat and, depending on the diagnosis, have a poor prognosis. Of brain tumors, glioblastoma (GBM) is the most common malignant glioma and has a dismal prognosis, with only about 5% of patients alive five years after diagnosis. While advances in targeted therapies and immunotherapies are rapidly improving outcomes in a variety of other cancers, the standard of care for GBM has largely remained unaltered since 2005. There are many well-studied challenges that are either unique to brain tumors (i.e., blood-brain barrier and immunosuppressive environment) or amplified within GBM (i.e., tumor heterogeneity at the cellular and molecular levels, plasticity, and cancer stem cells) that make this disease particularly difficult to treat. While we touch on all these concepts, the focus of this review is to discuss the immense inter- and intra-tumoral heterogeneity and advances in our understanding of tumor cell plasticity and epigenetics in GBM. With each improvement in technology, our understanding of the complexity of tumoral heterogeneity and plasticity improves and we gain more clarity on the causes underlying previous therapeutic failures. However, these advances are unlocking new therapeutic opportunities that scientists and physicians are currently exploiting and have the potential for new breakthroughs.

Cytotoxic Nitrobenzoyl Sesquiterpenoids from an Antarctica Sponge-Derived Aspergillus insulicola

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive neoplastic diseases of the pancreas with fatal proliferation and metastasis and no medicine available for treatment. From an Antarctica sponge-derived fungus, Aspergillus insulicola HDN151418, four new nitrobenzoyl sesquiterpenoids, namely, insulicolides D-G (1-4), were isolated. Compounds 3 and 4 exhibited selective inhibition against human PDAC cell lines. Further studies indicated that compound 4 could significantly suppress cell proliferation to induce apoptosis and blocked migration and invasion of PDAC cells. Compound 4 could also avoid resistance and improved the therapeutic effect of the chemotherapy drug gemcitabine. A preliminary mechanism study showed that compound 4 can significantly inhibit the expression of EGFR and XIAP in PDAC cells. Altogether, 4 is a potential lead compound for anti-PDAC drug research.

Novel Biomarker Genes for Prognosis of Survival and Treatment of Glioma

Glioblastoma multiforme (GBM) is the most aggressive malignant primary central nervous system tumor. Although surgery, radiotherapy, and chemotherapy treatments are available, the 5-year survival rate of GBM is only 5.8%. Therefore, it is imperative to find novel biomarker for the prognosis and treatment of GBM. In this study, a total of 141 differentially expressed genes (DEGs) in GBM were identified by analyzing the GSE12657, GSE90886, and GSE90598 datasets. After reducing the data dimensionality, Kaplan-Meier survival analysis indicated that expression of PTPRN and RIM-BP2 were downregulated in GBM tissues when compared with that of normal tissues and that the expression of these genes was a good prognostic biomarker for GBM (p<0.05). Then, the GSE46531 dataset and the Genomics of Drug Sensitivity in Cancer (GDSC) database were used to examine the relationship between sensitivity radiotherapy (RT) and chemotherapy for GBM and expression of PTPRN and RIM-BP2. The expression of PTPRN was significantly high in RT-resistant patients (p<0.05) but it was not related to temozolomide (TMZ) resistance. The expression level of RIM-BP2 was not associated with RT or TMZ treatment. Among the chemotherapeutic drugs, cisplatin and erlotinib had a significantly good treatment effect for glioma with expression of PTPRN or RIM-BP2 and in lower-grade glioma (LGG) with IDH mutation. (p < 0.05). The tumor mutational burden (TMB) score in the low PTPRN expression group was significantly higher than that in the high PTPRN expression group (p=0.013), with a large degree of tumor immune cell infiltration. In conclusion, these findings contributed to the discovery process of potential biomarkers and therapeutic targets for glioma patients.

Novel Ion Channel Targets and Drug Delivery Tools for Controlling Glioblastoma Cell Invasiveness

Comprising more than half of all brain tumors, glioblastoma multiforme (GBM) is a leading cause of brain cancer-related deaths worldwide. A major clinical challenge is presented by the capacity of glioma cells to rapidly infiltrate healthy brain parenchyma, allowing the cancer to escape control by localized surgical resections and radiotherapies, and promoting recurrence in other brain regions. We propose that therapies which target cellular motility pathways could be used to slow tumor dispersal, providing a longer time window for administration of frontline treatments needed to directly eradicate the primary tumors. An array of signal transduction pathways are known to be involved in controlling cellular motility. Aquaporins (AQPs) and voltage-gated ion channels are prime candidates as pharmacological targets to restrain cell migration in glioblastoma. Published work has demonstrated AQPs 1, 4 and 9, as well as voltage-gated potassium, sodium and calcium channels, chloride channels, and acid-sensing ion channels are expressed in GBM and can influence processes of cell volume change, extracellular matrix degradation, cytoskeletal reorganization, lamellipodial and filopodial extension, and turnover of cell-cell adhesions and focal assembly sites. The current gap in knowledge is the identification of optimal combinations of targets, inhibitory agents, and drug delivery systems that will allow effective intervention with minimal side effects in the complex environment of the brain, without disrupting finely tuned activities of neuro-glial networks. Based on published literature, we propose that co-treatments using AQP inhibitors in addition to other therapies could increase effectiveness, overcoming some limitations inherent in current strategies that are focused on single mechanisms. An emerging interest in nanobodies as drug delivery systems could be instrumental for achieving the selective delivery of combinations of agents aimed at multiple key targets, which could enhance success in vivo.

Machine Learning Analytics of Resting-State Functional Connectivity Predicts Survival Outcomes of Glioblastoma Multiforme Patients

Glioblastoma multiforme (GBM) is the most frequently occurring brain malignancy. Due to its poor prognosis with currently available treatments, there is a pressing need for easily accessible, non-invasive techniques to help inform pre-treatment planning, patient counseling, and improve outcomes. In this study we determined the feasibility of resting-state functional connectivity (rsFC) to classify GBM patients into short-term and long-term survival groups with respect to reported median survival (14.6 months). We used a support vector machine with rsFC between regions of interest as predictive features. We employed a novel hybrid feature selection method whereby features were first filtered using correlations between rsFC and OS, and then using the established method of recursive feature elimination (RFE) to select the optimal feature subset. Leave-one-subject-out cross-validation evaluated the performance of models. Classification between short- and long-term survival accuracy was 71.9%. Sensitivity and specificity were 77.1 and 65.5%, respectively. The area under the receiver operating characteristic curve was 0.752 (95% CI, 0.62–0.88). These findings suggest that highly specific features of rsFC may predict GBM survival. Taken together, the findings of this study support that resting-state fMRI and machine learning analytics could enable a radiomic biomarker for GBM, augmenting care and planning for individual patients.

Efficacy of osimertinib against EGFRvIII+ glioblastoma

Epidermal Growth Factor Receptor variant III (EGFRvIII) is an active mutant form of EGFR that drives tumor growth in a subset of glioblastoma (GBM). It occurs in over 20% of GBMs, making it a promising receptor for small molecule targeted therapy. We hypothesize that poor penetration of the blood-brain barrier by previously tested EGFR-tyrosine kinase inhibitors (EGFR-TKIs) such as afateninb, erlotinib, gefitinib, and lapatinib played a role in their limited efficacy. The present study examined the effects of osimertinib (previously known as AZD9291) on EGFRvIII+ GBM models, both in vitro and in vivo. Therefore, a panel of six GBM stem cells (GSCs) expressing EGFRvIII+ was evaluated. The EGFRvIII+ GSC differed in the expression of EGFRvIII and other key genes. The GSC line D317, which expresses high levels of EGFRvIII and has robust tyrosine kinase activity, was selected for assessing osimertinib’s efficacy. Herein, we report that osimertinib inhibits the constitutive activity of EGFRvIII tyrosine kinase with high potency (<100 nM) while also inhibiting its downstream signaling. Further, osimertinib inhibited D317’s growth in vitro and in both heterotopic and orthotopic xenograft models. Additional preclinical studies are warranted to identify EGFRvIII+ GBM’s molecular signature most responsive to osimertinib.

Breast Cancer Patient with Li-Fraumeni Syndrome: A Case Report Highlighting the Importance of Multidisciplinary Management

Germline mutations in TP53, a tumor suppressor gene, are involved in the development of Li-Fraumeni syndrome, a rare disorder that predisposes carriers to multiple tumors. TP53 mutations have been associated with resistance to treatment and poor prognosis. A young female with the pathogenic germline TP53 mutation c.844C > T (p.R282W) was diagnosed with two metachronous breast tumors, one HER2-negative and the other HER2-positive. She was later diagnosed with synchronous glioblastoma, epidermal growth factor receptor-mutated lung adenocarcinoma, and HER2-negative breast cancer metastases. The patient was treated with local therapies, including brain surgery and radiotherapy, lung surgery, and a bilateral mastectomy, as well as with targeted systemic treatment. She proved to be highly sensitive to systemic therapy, and 13 years after the initial diagnosis of breast cancer and 6 years after the diagnosis of the two new primary tumors and recurrence of a prior cancer, she is alive with an excellent performance status. This surprising positive evolution may well be partly due to the pronged multidisciplinary approach to managing her disease and her extraordinary response to treatment: the lung adenocarcinoma showed excellent response to erlotinib; the breast cancer responded extremely well to eribulin and pegylated liposomal doxorubicin; and the glioblastoma has remained in response to surgery and radiotherapy. Despite harboring a TP53 mutation and having multiple tumors, this patient has shown an unexpectedly favorable evolution. The coordinated participation of a multidisciplinary team and the patient's own extraordinarily high sensitivity to systemic treatment played a major role in this evolution.

Heme Oxygenase-1 and Carbon Monoxide Regulate Growth and Progression in Glioblastoma Cells

In human glioma tumours, heme oxygenase-1 (HO-1) is overexpressed when compared with normal brain tissues and during oligodendroglioma progression. However, the molecular mechanisms mediated by HO-1 to promote glioblastoma remain unknown. We therefore aimed at investigating the effect of HO-1 expression and its selective enzymatic inhibition in two different cell lines (i.e. A172 and U87-MG). HO-1 was induced by hemin treatment (10 μM), and VP13/47 (100 μM) was used as a specific non-competitive inhibitor of HO-1 activity. Cell proliferation was measured by cell index measurement (xCelligence technology) and clonogenic assay, whereas cell migration was assessed by wound healing assay. Carbon monoxide-releasing molecules (CORMs) (i.e. CORM-3 and CORM-A1) were also used in a separate set of experiments to confirm the effect of HO-1 by-product in glioblastoma progression further. Our results were further validated using GSE4412 microarray dataset analysis and comparing biopsies overexpressing HO-1 with the rest of the cases. Our results showed that hemin was able to induce both HO-1 gene and protein expression in a cell-dependent manner being A172 more responsive to pharmacological upregulation of HO-1. Hemin, but not CORMs treatment, resulted in a significant increase of cell proliferation following 24 h of treatment as measured by increased cell index and colony formation capacity and such effect was abolished by VP13/47. Interestingly, both hemin and CORMs showed a significant effect on the wound healing assay also exhibiting cell specificity. Finally, our dataset analysis showed a positive correlation of HO-1 gene expression with ITGBI and ITGBII which are membrane receptors involved in cell adhesion, embryogenesis, tissue repair, immune response and metastatic diffusion of tumour cells. In conclusion, our data suggest that HO-1 and its by-product CO exhibit a cell-specific effect on various aspects of disease progression and are associated with a complex series of molecular mechanisms driving cell proliferation, survival and metastasis.

Receptor Tyrosine Kinases: Principles and Functions in Glioma Invasion

Protein tyrosine kinases are enzymes that are capable of adding a phosphate group to specific tyrosines on target proteins. A receptor tyrosine kinase (RTK) is a tyrosine kinase located at the cellular membrane and is activated by binding of a ligand via its extracellular domain. Protein phosphorylation by kinases is an important mechanism for communicating signals within a cell and regulating cellular activity; furthermore, this mechanism functions as an "on" or "off" switch in many cellular functions. Ninety unique tyrosine kinase genes, including 58 RTKs, were identified in the human genome; the products of these genes regulate cellular proliferation, survival, differentiation, function, and motility. Tyrosine kinases play a critical role in the development and progression of many types of cancer, in addition to their roles as key regulators of normal cellular processes. Recent studies have revealed that RTKs such as epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), c-Met, Tie, Axl, discoidin domain receptor 1 (DDR1), and erythropoietin-producing human hepatocellular carcinoma (Eph) play a major role in glioma invasion. Herein, we summarize recent advances in understanding the role of RTKs in glioma pathobiology, especially the invasive phenotype, and present the perspective that RTKs are a potential target of glioma therapy.

Role of 17β-Estradiol on Cell Proliferation and Mitochondrial Fitness in Glioblastoma Cells

Gliomas are the most common primary tumors of the central nervous system (CNS) in the adult. Previous data showed that estrogen affects cancer cells, but its effect is cell-type-dependent and controversial. The present study aimed to analyze the effects of estradiol (E2, 5 nM) in human glioblastoma multiforme U87-MG cells and how it may impact on cell proliferation and mitochondrial fitness. We monitored cell proliferation by xCELLigence technology and mitochondrial fitness by assessing the expression of genes involved in mitochondrial biogenesis (PGC1α, SIRT1, and TFAM), oxidative phosphorylation (ND4, Cytb, COX-II, COX IV, NDUFA6, and ATP synthase), and dynamics (OPA1, MNF2, MNF1, and FIS1). Finally, we evaluated Nrf2 nuclear translocation by immunocytochemical analysis. Our results showed that E2 resulted in a significant increase in cell proliferation, with a significant increase in the expression of genes involved in various mechanisms of mitochondrial fitness. Finally, E2 treatment resulted in a significant increase of Nrf2 nuclear translocation with a significant increase in the expression of one of its target genes (i.e., heme oxygenase-1). Our results suggest that E2 promotes proliferation in glioblastoma cells and regulate the expression of genes involved in mitochondrial fitness and chemoresistance pathway.

Origins and clinical relevance of proteoforms in pediatric malignancies

INTRODUCTION

Cancer changes the proteome in complex ways that reach well beyond simple changes in protein abundance. Genomic and transcriptional variations and post-translational protein modification create functional variants of a protein, known as proteoforms. Childhood cancers have fewer genomic alterations but show equally dramatic phenotypic changes as malignant cells in adults. Therefore, unraveling the complexities of the proteome is even more important in pediatric malignancies. Areas covered: In this review, the biological origins of proteoforms and technological advancements in the study of proteoforms are discussed. Particular emphasis is given to their implication in childhood malignancies and the critical role of cancer-specific proteoforms for the next generation of cancer therapies and diagnostics. Expert opinion: Recent advancements in technology have led to a better understanding of the underlying mechanisms of tumorigenesis. This has been critical for the development of more effective and less harmful treatments that are based on direct targeting of altered proteins and deregulated pathways. As proteome coverage and the ability to detect complex proteoforms increase, the most need for change is in data compilation and database availability to mediate high-level data analysis and allow for better functional annotation of proteoforms.

Genetically distinct glioma stem-like cell xenografts established from paired glioblastoma samples harvested before and after molecularly targeted therapy

Intratumoural heterogeneity underlies tumour escape from molecularly targeted therapy in glioblastoma. A cell-based model preserving the evolving molecular profiles of a tumour during treatment is key to understanding the recurrence mechanisms and development of strategies to overcome resistance. In this study, we established a matched pair of glioblastoma stem-like cell (GSC) cultures from patient glioblastoma samples before and after epidermal growth factor receptor (EGFR)-targeted therapy. A patient with recurrent glioblastoma (MGG70R) harboring focal, high-level EGFR amplification received the irreversible EGFR tyrosine kinase inhibitor dacomitinib. The tumour that subsequently recurred (MGG70RR) showed diploid EGFR, suggesting inhibitor-mediated elimination of EGFR-amplified tumour cells and propagation of EGFR non-amplified cell subpopulations. The MGG70R-GSC line established from MGG70R formed xenografts retaining EGFR amplification and EGFR overexpression, while MGG70RR-GSC established from MGG70RR generated tumours that lacked EGFR amplification and EGFR overexpression. MGG70R-GSC-derived intracranial xenografts were more proliferative than MGG70RR-GSC xenografts, which had upregulated mesenchymal markers, mirroring the pathological observation in the corresponding patient tumours. In vitro MGG70R-GSC was more sensitive to EGFR inhibitors than MGG70RR-GSC. Thus, these molecularly distinct GSC lines recapitulated the subpopulation alteration that occurred during glioblastoma evasion of targeted therapy, and offer a valuable model facilitating therapeutic development for recurrent glioblastoma.

Prognostic implications of epidermal growth factor receptor variant III expression and nuclear translocation in Chinese human gliomas

Objective

To determine the prognostic implications and clinical significance of epidermal growth factor receptor variant III (EGFRvIII) expression and EGFRvIII nuclear translocation in Chinese human gliomas.

Methods

We retrospectively examined EGFRvIII expression and EGFRvIII nuclear translocation using immunohistochemistry in specimens of 240 Chinese patients with glioma, including 84 World Health Organization (WHO) II gliomas, 84 WHO III gliomas and 72 glioblastomas (WHO IV). Factors that correlated with EGFRvIII and EGFRvIII nuclear translocation expression were analyzed by the Chi-square test. Kaplan-Meier methodology and Cox regression were used for the survival analysis.

Results

Log-rank tests showed that patient age, Karnofsky performance scale (KPS) score, tumor grade, EGFRvIII expression, EGFRvIII nuclear translocation, 1p/19q codeletion, isocitrate dehydrogenase (IDH) mutation, Ki-67 labeling index and O6-methylguanine-DNA methyltransferase (MGMT) status (P<0.05) were significantly correlated with overall survival (OS) time. Multivariate Cox regression analysis revealed that patient age, tumor grade, EGFRvIII nuclear translocation, 1p/19q codeletion, and IDH mutation (P<0.05) were significantly correlated with OS. Patients with a high level of EGFRvIII nuclear translocation (≥7%) had both significantly shorter OS [hazard ratio (HR): 1.920, 95% confidence interval (95% CI): 1.228−3.003, P=0.004] and progression-free survival (PFS) times (HR: 1.661, 95% CI: 1.116−2.471, P=0.012) than those with a low level of EGFRvIII nuclear translocation (<7%).

Conclusions

A high level of EGFRvIII nuclear translocation in glioma is an independent factor indicating a poor prognosis, but EGFRvIII expression is not an independent clinical prognostic factor. The level of EGFRvIII nuclear translocation maybe a novel and crucial prognostic biomarker in glioma.

Dacomitinib: an investigational drug for the treatment of glioblastoma

INTRODUCTION

Standard treatment of newly diagnosed glioblastoma (GB) is surgery with radiotherapy and temozolomide, but tumors will recur with a median overall survival of only 15 months. It seems imperative to explore new possibilities of treatment based on targetable alterations known to be present in GB. Among others, Epidermal Growth Factor Receptor or EGFR (HER1) mutations or amplifications are the most prevalent alterations in GB. In fact, around 40% of GB cases show amplification of EGFR gene, and half of these patients carry the EGFRvIII mutation, a deletion that generates a continuous activation of the tyrosine kinase domain of the receptor. Areas covered: We review the current knowledge about Dacomitinib, an oral, irreversible, second-generation, pan-HER tyrosine kinase inhibitor, in the treatment of glioblastoma. Dacomitinib has noteworthy antiglioma activity in preclinical models and has been tested in one phase II trial in patients with recurrent GB with EGFR amplification. Expert opinion: Despite the poor global results of Dacomitinib in recurrent GB shown in a phase II trial, some patients had a significant benefit. Therefore, it is necessary to improve the knowledge about the mechanisms of failure or resistance to EGFR inhibitors in GB.

Using genomics to guide treatment for glioblastoma

Glioblastoma has been shown to have many different genetic mutations found both within and between tumor samples. Molecular testing and genomic sequencing has helped to classify diagnoses and clarify difficult to interpret histopathological specimens. Genomic information also plays a critical role in prognostication for patients, with IDH mutations and MGMT methylation having significant impact of the response to chemotherapy and overall survival of patients. Unfortunately, personalized medicine and targeted therapy against specific mutations have not been shown to improve patient outcomes. As technology continues to improve, exome and RNA sequencing will play a role in the design of clinical trials, classification of patient subgroups and identification of rare mutations that can be targeted by small-molecule inhibitors and biologic agents.

EGFR as a clinical marker in glioblastomas and other gliomas

Epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein and a member of the tyrosine kinase superfamily receptor. Gliomas are tumors originating from glial cells, which show a range of aggressiveness depending on grade and stage. Many EGFR gene alterations have been identified in gliomas, especially glioblastomas, including amplifications, deletions and single nucleotide polymorphisms (SNPs). Glioblastomas are discussed as a separate entity due to their high correlation with EGFR mutants and the reported association of the latter with survival and response to treatment in this glioma subgroup. This review is a comprehensive report of EGFR gene alterations and their relations with several clinical factors in glioblastomas and other gliomas. It covers all EGFR gene alterations including point mutations, SNPs, methylations, copy number variations and amplifications, assessed with regard to different clinical variables, including response to therapy and survival. This review also discusses the current prognostic status of EGFR in glioblastomas and other gliomas, and highlights gaps in previous studies. This serves as an update for the medical community about the role of EGFR gene alterations in gliomas and specifically glioblastomas, as a means for targeted treatment and prognosis.

Activation of ERBB4 in Glioblastoma Can Contribute to Increased Tumorigenicity and Influence Therapeutic Response

Glioblastoma (GBM) is often resistant to conventional and targeted therapeutics. ErbB2 Receptor Tyrosine Kinase 4 (ERBB4) is expressed throughout normal brain and is an oncogene in several pediatric brain cancers; therefore, we investigated ERBB4 as a prognostic marker and therapeutic target in GBM. Using RT-qPCR, we quantified mRNA encoding total ERBB4 and known ERBB4 variants in GBM and non-neoplastic normal brain (NNB) samples. Using immunohistochemistry, we characterized the localization of total and phosphorylated ERBB4 (p-ERBB4) and EGFR protein in archived GBM samples and assessed their association with patient survival. Furthermore, we evaluated the effect of ERBB4 phosphorylation on angiogenesis and tumorigenicity in GBM xenograft models. Total ERBB4 mRNA was significantly lower in GBM than NNB samples, with the juxtamembrane JM-a and cytoplasmic CYT-2 variants predominating. ERBB4 protein was ubiquitously expressed in GBM but was not associated with patient survival. However, high p-ERBB4 in 11% of archived GBM samples, independent of p-EGFR, was associated with shorter patient survival (12.0 ± 3.2 months) than was no p-ERBB4 (22.5 ± 9.5 months). Increased ERBB4 activation was also associated with increased proliferation, angiogenesis, tumorigenicity and reduced sensitivity to anti-EGFR treatment in xenograft models. Despite low ERBB4 mRNA in GBM, the functional effects of increased ERBB4 activation identify ERBB4 as a potential prognostic and therapeutic target.

Connexin 43 C-terminus directly inhibits the hyperphosphorylation of Akt/ERK through protein-protein interactions in glioblastoma

Although the deregulation of epidermal growth factor receptor (EGFR) is one of the most common molecular mechanisms of glioblastoma (GBM) pathogenesis, the efficacy of anti-EGFR therapy is limited. Additionally, response to anti-EGFR therapy is not solely dependent on EGFR expression and is more promising in patients with reduced activity of EGFR downstream signaling pathways. Thus, there is considerable interest in identifying the compensatory regulatory factors of the EGFR signaling pathway to improve the efficacy of anti-EGFR therapies for GBM. In this study, we confirmed the low efficacy of EGFR inhibitors in GBM patients by meta-analysis. We then identified a negative correlation between connexin 43 (Cx43) expression and Akt/ERK activation, which was caused by the direct interactions between Akt/ERK and Cx43. By comparing the interactions between Akt/ERK and Cx43 using a series of truncated and mutated Cx43 variants, we revealed that the residues T286/A305/Q308/Y313 and S272/S273 at the carboxy terminus of Cx43 are critical for its binding with Akt and ERK, respectively. In addition, Kaplan-Meier survival analysis using data from The Cancer Genome Atlas datasets indicated that the expression of Cx43 significantly improved the prognosis of GBM patients who express EGFR. Together, our results suggested that Cx43 acts as an inhibitory regulator of the activation of growth factor receptor downstream signaling pathways, indicating the potential of Cx43 as a marker for predicting the efficacy of EGFR inhibitor treatments for GBM. Targeting the interaction between the carboxy terminus of Cx43 and Akt/ERK could be an effective therapeutic strategy against GBM.

Next generation sequencing and molecular imaging identify EGFR mutation and amplification in a glioblastoma multiforme patient treated with an EGFR inhibitor: a case report

Epidermal growth factor receptor (EGFR) mutations and amplifications are frequently reported in glioblastoma multiforme (GBM) patients. In this case report, we utilize next-generation sequencing (NGS) and EGFR molecular imaging to investigate intratumoral heterogeneity in a male patient presenting with GBM. Further, we describe the patient's clinical course as well as outcomes of targeted EGFR therapy with erlotinib, an EGFR tyrosine kinase inhibitor (TKI). NGS demonstrated the presence of an EGFR mutation and amplification in our patient. Molecular imaging revealed a heterogeneous expression pattern of EGFR in the frontal and temporal lobes. This patient briefly responded to erlotinib therapy. However, the patient relapsed and died from progressive neurological deterioration. Partial response and acquired secondary resistance may be attributed to intratumoral heterogeneity. Combination of NGS and EGFR molecular imaging may be helpful in understanding intratumoral molecular heterogeneity and may aid in developing individualized GBM treatments, thereby improving outcomes.

Genome-Scale Signatures of Gene Interaction from Compound Screens Predict Clinical Efficacy of Targeted Cancer Therapies

Identifying reliable drug response biomarkers is a significant challenge in cancer research. We present computational analysis of resistance (CARE), a computational method focused on targeted therapies, to infer genome-wide transcriptomic signatures of drug efficacy from cell line compound screens. CARE outputs genome-scale scores to measure how the drug target gene interacts with other genes to affect the inhibitor efficacy in the compound screens. Such statistical interactions between drug targets and other genes were not considered in previous studies but are critical in identifying predictive biomarkers. When evaluated using transcriptome data from clinical studies, CARE can predict the therapy outcome better than signatures from other computational methods and genomics experiments. Moreover, the CARE signatures for the PLX4720 BRAF inhibitor are associated with an anti-programmed death 1 clinical response, suggesting a common efficacy signature between a targeted therapy and immunotherapy. When searching for genes related to lapatinib resistance, CARE identified PRKD3 as the top candidate. PRKD3 inhibition, by both small interfering RNA and compounds, significantly sensitized breast cancer cells to lapatinib. Thus, CARE should enable large-scale inference of response biomarkers and drug combinations for targeted therapies using compound screen data.

Treatment of Glioblastoma in Elderly Patients: An Overview of Current Treatments and Future Perspective

Current treatment of glioblastoma in the elderly includes surgery, radiotherapy and chemotherapy, but the prognosis remains extremely poor, and its optimal management is still debated. Longer survival after extensive resection compared with biopsy only has been reported, although the survival advantage remains modest. Radiation in the form of standard (60 Gy in 30 fractions over 6 weeks) and abbreviated courses of radiotherapy (30–50 Gy in 6–20 fractions over 2–4 weeks) has been employed in elderly patients with glioblastoma, showing survival benefits compared with supportive care alone. Temozolomide is an alkylating agent recently employed in older patients with newly diagnosed glioblastoma. The addition of concomitant and/or adjuvant chemotherapy with temozolomide to radiotherapy, which is currently the standard treatment in adults with glioblastoma, is emerging as an effective therapeutic option for older patients with favorable prognostic factors. The potential benefits on survival, improvement in quality of life and toxicity of different schedules of radiotherapy plus temozolomide need to be addressed in future randomized studies. Free full text available at www.tumorionline.it

Significant Effect of Anti-tyrosine Kinase Inhibitor (Gefitinib) on Overall Survival of the Glioblastoma Multiforme Patients in the Backdrop of Mutational Status of Epidermal Growth Factor Receptor and PTEN Genes

Introduction:

We aimed to assess the effect of anti-tyrosine kinase inhibitors (TKIs) (gefitinib) in overall survival (OS) of the glioblastoma multiforme (GBM) patients in the backdrop of mutational status of epidermal growth factor receptor (EGFR) and PTEN genes.

Materials and Methods:

All the patients subjected to resection or biopsies were put on gefitinib, and radiotherapy was delivered as per the hospital protocol. EGFR and PTEN mutational spectrum was performed by single-strand conformation polymorphism followed by DNA sequencing.

Results:

In total, 50% GBM tumors had mutation either in EGFR or PTEN. Median progression-free survival (PFS) and OS observed in patients with EGFR +ve/PTEN −ve were significantly favorable (P < 0.05) which aggregated to 9(7, 11) months and 20 (16, 24) months, respectively, than 6 (4, 8) months and 13 (7, 19) months in patients with PTEN +ve/EGFR −ve. Patients positive for both EGFR/PTEN had lower disease-free survival and OS of 6 and 9 months as compared to 6 (5, 7) and 14 (12, 24) months for those negative for both EGFR/PTEN.

Conclusions:

We conclude that EGFR gene alterations with wild-type PTEN are associated with significantly better PFS and OS in patients treated with anti-TKIs (gefitinib). Combined EGFR and PTEN gene mutation is associated with significantly poor response to gefitinib in terms of median OS.

PI3K/Akt/mTOR signaling pathway and targeted therapy for glioblastoma

Glioblastoma multiform (GBM) is the most common malignant glioma of all the brain tumors and currently effective treatment options are still lacking. GBM is frequently accompanied with overexpression and/or mutation of epidermal growth factor receptor (EGFR), which subsequently leads to activation of many downstream signal pathways such as phosphatidylinositol 3-kinase (PI3K)/Akt/rapamycin-sensitive mTOR-complex (mTOR) pathway. Here we explored the reason why inhibition of the pathway may serve as a compelling therapeutic target for the disease, and provided an update data of EFGR and PI3K/Akt/mTOR inhibitors in clinical trials.

An EGFR and AKT Signaling Pathway was Identified with Mediation Model in Osteosarcomas Clinical Study

Identification of correlation pattern and signal pathway among biomarkers in patients has become increasingly interesting for its potential values in diagnosis, treatment and prognosis. EGFR and p-AKT signaling in osteosarcoma (OS) patients were analyzed for its relationship with cancer cell proliferation maker, Ki-67, using causal procedures and statistical tests. A total of 69 patients were collected who present to Vanderbilt University Medical Center with newly diagnosed, previously untreated osteosarcomas during the clinical study period 1994 through 2003. Tissue microarrays were constructed for EGFR, p-AKT and Ki-67. The mediation model was constructed with structural equation model (SEM) for the causal analysis of the three biomarkers in osteosarcoma patients. The results suggested a mediating effect of p-AKT for the causal relationship between EGFR and Ki-67. The study also found significant associations between EGFR and Ki-67 (p = 0.002), EGFR and p-AKT (p = 0.027), and p-AKT and Ki-67 controlling EGFR (p = 0.004). After the impact of EGFR on Ki-67 was accounted for by p-AKT, the relation between EGFR and Ki-67 was no longer significant (p = 0.381). The mediating effect was confirmed with Sobel test (p < 0.001) and Goodman (I) test (p < 0.001). The study indicated that a mediation model could be an approach to exploring the correlation pattern of EGFR and AKT signal pathway for cancer cell proliferation in OS patients in clinical study.

Glioblastoma update: molecular biology, diagnosis, treatment, response assessment, and translational clinical trials

This is an exciting time in neuro-oncology. Discoveries elucidating the molecular mechanisms of oncogenesis and the molecular subtypes of glioblastoma multiforme (GBM) have led to new diagnostic and classification schemes with more prognostic power than histology alone. Molecular profiling has become part of the standard neuropathological evaluation of GBM. Chemoradiation followed by adjuvant temozolomide remains the standard therapy for newly diagnosed GBM, but survival remains unsatisfactory. Patients with recurrent GBM continue to have a dismal prognosis, but neuro-oncology centers with active clinical trial programs are seeing a small but increasing cadre of patients with longer survival. Molecularly targeted therapeutics, personalized therapy based on molecular profiling of individual tumors, and immunotherapeutic strategies are all being evaluated and refined in clinical trials. Understanding of the molecular mechanisms of tumor-mediated immunosuppression, and specifically interactions between tumor cells and immune effector cells in the tumor microenvironment, has led to a new generation of immunotherapies, including vaccine and immunomodulatory strategies as well as T-cell-based treatments. Molecularly targeted therapies, chemoradiation, immunotherapies, and anti-angiogenic therapies have created the need to develop more reliable neuroimaging criteria for differentiating the effects of therapy from tumor progression and changes in blood–brain barrier physiology from treatment response. Translational clinical trials for patients with GBM now incorporate quantitative imaging using both magnetic resonance imaging and positron emission tomography techniques. This update presents a summary of the current standards for therapy for newly diagnosed and recurrent GBM and highlights promising translational research.

A Rational Approach to Target the Epidermal Growth Factor Receptor in Glioblastoma

Glioblastoma (GBM) is a deadly brain cancer, and all attempts to control it have failed so far. However, the future looks bright, as we now know the molecular landscape of GBM through the work of The Cancer Genome Atlas (TCGA) program. GBMs exhibit significant inter- and intratumoral heterogeneity, and to control this type of tumor, a personalized approach is required. One target, whose gene is amplified and mutated in a large number of GBMs, is the epidermal growth factor receptor (EGFR). But all attempts to target it have been unsuccessful. We attribute the reason for this failure to the molecular heterogeneity of EGFR in GBM, as well as to the poor brain penetration of previously tested EGFR-Tyrosine Kinase Inhibitors (EGFR-TKIs). In this review, we discuss the molecular heterogeneity of EGFR and provide rational preclinical and clinical guidelines for testing AZD9291, a third generation, irreversible EGFR-TKI with both a high affinity for EGFRvIII and excellent brain penetration.

[Analysis of contribution of protein phosphorylation in the development of the diseases]

In recent decades, studies in the molecular origins of socially significant diseases have made a big step forward with the development and using of high-performance methods in genomics and proteomics. Numerous studies in the framework of the global program "Human Proteome" were aimed at the identification of all possible proteins in various cell cultures and tissues, including cancer. One of the objectives was to identify biomarkers - proteins with high specificity to certain pathologies. However, in many cases, it is shown that the development of the disease is not associated with the appearance of new proteins, but depends on the level of gene expression or forming of proteoforms - splice variants, single amino acid substitutions (SAP variants), and post-translational modifications (PTM) of proteins. PTM may play a key role in the development of pathology because they activate a variety of regulatory or structural proteins in the majority of cell physiological processes. Phosphorylation is among the most significant of these protein modifications.This review will describe methods for analysis of protein phosphorylation used in the studies of such diseases as cancer and neurodegenerative diseases, as well as examples of cases when the modified proteins are involved directly to their development, and screening such significant PTM is used for the diagnosis and choice of treatment.

The Effect of Molecular Diagnostics on the Treatment of Glioma

PURPOSE OF REVIEW

This review summarizes the use of molecular diagnostics in glioma and its effect on the development of novel therapeutics and management decisions.

RECENT FINDINGS

Genomic and proteomic profiling of brain tumors has provided significant expansion of our understanding of oncogenesis, characterization, and prognostication of brain tumors. Molecular markers such as MGMT, EGFR, IDH, 1p19q, ATRX, TERT, FGFR-TACC, and BRAF are now being used to classify brain tumors as well as influence management decisions. Several of these markers are also being used as therapeutic targets. We review the use of several molecular diagnostics in gliomas and discuss their impact on drug development and clinical trial design. In the future, molecular characterization based on a specific genomic, proteomic as well as transcriptomes for bioformatics analysis will provide clinicians the ability to rationally select drugs with actionable targets for each patient.

Glioblastoma targeted therapy: updated approaches from recent biological insights

Glioblastoma (WHO grade IV astrocytoma) is the most frequent primary brain tumor in adults, representing a highly heterogeneous group of neoplasms that are among the most aggressive and challenging cancers to treat. An improved understanding of the molecular pathways that drive malignancy in glioblastoma has led to the development of various biomarkers and the evaluation of several agents specifically targeting tumor cells and the tumor microenvironment. A number of rational approaches are being investigated, including therapies targeting tumor growth factor receptors and downstream pathways, cell cycle and epigenetic regulation, angiogenesis and antitumor immune response. Moreover, recent identification and validation of prognostic and predictive biomarkers have allowed implementation of modern trial designs based on matching molecular features of tumors to targeted therapeutics. However, while occasional targeted therapy responses have been documented in patients, to date no targeted therapy has been formally validated as effective in clinical trials. The lack of knowledge about relevant molecular drivers in vivo combined with a lack of highly bioactive and brain penetrant-targeted therapies remain significant challenges. In this article, we review the most promising biological insights that have opened the way for the development of targeted therapies in glioblastoma, and examine recent data from clinical trials evaluating targeted therapies and immunotherapies. We discuss challenges and opportunities for the development of these agents in glioblastoma.

Diagnostic and Therapeutic Biomarkers in Glioblastoma: Current Status and Future Perspectives

Glioblastoma (GBM) is a primary neuroepithelial tumor of the central nervous system, characterized by an extremely aggressive clinical phenotype. Patients with GBM have a poor prognosis and only 3–5% of them survive for more than 5 years. The current GBM treatment standards include maximal resection followed by radiotherapy with concomitant and adjuvant therapies. Despite these aggressive therapeutic regimens, the majority of patients suffer recurrence due to molecular heterogeneity of GBM. Consequently, a number of potential diagnostic, prognostic, and predictive biomarkers have been investigated. Some of them, such as IDH mutations, 1p19q deletion, MGMT promoter methylation, and EGFRvIII amplification are frequently tested in routine clinical practice. With the development of sequencing technology, detailed characterization of GBM molecular signatures has facilitated a more personalized therapeutic approach and contributed to the development of a new generation of anti-GBM therapies such as molecular inhibitors targeting growth factor receptors, vaccines, antibody-based drug conjugates, and more recently inhibitors blocking the immune checkpoints. In this article, we review the exciting progress towards elucidating the potential of current and novel GBM biomarkers and discuss their implications for clinical practice.

Advances in Molecular Imaging of Locally Delivered Targeted Therapeutics for Central Nervous System Tumors

Thanks to the recent advances in the development of chemotherapeutics, the morbidity and mortality of many cancers has decreased significantly. However, compared to oncology in general, the field of neuro-oncology has lagged behind. While new molecularly targeted chemotherapeutics have emerged, the impermeability of the blood–brain barrier (BBB) renders systemic delivery of these clinical agents suboptimal. To circumvent the BBB, novel routes of administration are being applied in the clinic, ranging from intra-arterial infusion and direct infusion into the target tissue (convection enhanced delivery (CED)) to the use of focused ultrasound to temporarily disrupt the BBB. However, the current system depends on a “wait-and-see” approach, whereby drug delivery is deemed successful only when a specific clinical outcome is observed. The shortcomings of this approach are evident, as a failed delivery that needs immediate refinement cannot be observed and corrected. In response to this problem, new theranostic agents, compounds with both imaging and therapeutic potential, are being developed, paving the way for improved and monitored delivery to central nervous system (CNS) malignancies. In this review, we focus on the advances and the challenges to improve early cancer detection, selection of targeted therapy, and evaluation of therapeutic efficacy, brought forth by the development of these new agents.

Cerebral Gluconeogenesis and Diseases

The gluconeogenesis pathway, which has been known to normally present in the liver, kidney, intestine, or muscle, has four irreversible steps catalyzed by the enzymes: pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, and glucose 6-phosphatase. Studies have also demonstrated evidence that gluconeogenesis exists in brain astrocytes but no convincing data have yet been found in neurons. Astrocytes exhibit significant 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 activity, a key mechanism for regulating glycolysis and gluconeogenesis. Astrocytes are unique in that they use glycolysis to produce lactate, which is then shuttled into neurons and used as gluconeogenic precursors for reduction. This gluconeogenesis pathway found in astrocytes is becoming more recognized as an important alternative glucose source for neurons, specifically in ischemic stroke and brain tumor. Further studies are needed to discover how the gluconeogenesis pathway is controlled in the brain, which may lead to the development of therapeutic targets to control energy levels and cellular survival in ischemic stroke patients, or inhibit gluconeogenesis in brain tumors to promote malignant cell death and tumor regression. While there are extensive studies on the mechanisms of cerebral glycolysis in ischemic stroke and brain tumors, studies on cerebral gluconeogenesis are limited. Here, we review studies done to date regarding gluconeogenesis to evaluate whether this metabolic pathway is beneficial or detrimental to the brain under these pathological conditions.

The strange connection between epidermal growth factor receptor tyrosine kinase inhibitors and dapsone: from rash mitigation to the increase in anti-tumor activity

The presence of an aberrantly activated epidermal growth factor receptor (EGFR) in many epithelial tumors, due to its overexpression, activating mutations, gene amplification and/or overexpression of receptor ligands, represent the fundamental basis underlying the use of EGFR tyrosine kinase inhibitors (EGFR-TKIs). Drugs inhibiting the EGFR have different mechanisms of action; while erlotinib and gefitinib inhibit the intracellular tyrosine kinase, monoclonal antibodies like cetuximab and panitumumab bind the extracellular domain of the EGFR both activating immunomediated anti-cancer effect and inhibiting receptor function. On the other hand, interleukin-8 has tumor promoting as well as neo-angiogenesis enhancing effects and several attempts have been made to inhibit its activity. One of these is based on the use of the old sulfone antibiotic dapsone that has demonstrated several interleukin-8 system inhibiting actions. Erlotinib typically gives a rash that has recently been proven to come out via up-regulated keratinocyte interleukin-8 synthesis with histological features reminiscent of typical neutrophilic dermatoses. In this review, we report experimental evidence that shows the use of dapsone to improve quality of life in erlotinib-treated patients by ameliorating rash as well as short-circuiting a growth-enhancing aspect of erlotinib based on increased interleukin-8 secretion.

A phase II study of bevacizumab and erlotinib after radiation and temozolomide in MGMT unmethylated GBM patients

Survival for glioblastoma (GBM) patients with an unmethyated MGMT promoter in their tumor is generally worse than methylated MGMT tumors, as temozolomide (TMZ) response is limited. How to better treat patients with unmethylated MGMT is unknown. We performed a trial combining erlotinib and bevacizumab in unmethylated GBM patients after completion of radiation (RT) and TMZ. GBM patients with an unmethylated MGMT promoter were trial eligible. Patient received standard RT (60 Gy) and TMZ (75 mg/m2 × 6 weeks) after surgical resection of their tumor. After completion of RT they started erlotinib 150 mg daily and bevacizumab 10 mg/kg every 2 weeks until progression. Imaging evaluations occurred every 8 weeks. The primary endpoint was overall survival. Of the 48 unmethylated patients enrolled, 46 were evaluable (29 men and 17 women); median age was 55.5 years (29-75) and median KPS was 90 (70-100). All patients completed RT with TMZ. The median number of cycles (1 cycle was 4 weeks) was 8 (2-47). Forty-one patients either progressed or died with a median progression free survival of 9.2 months. At a follow up of 33 months the median overall survival was 13.2 months. There were no unexpected toxicities and most observed toxicities were categorized as CTC grade 1 or 2. The combination of erlotinib and bevacizumab is tolerable but did not meet our primary endpoint of increasing survival. Importantly, more trials are needed to find better therapies for GBM patients with an unmethylated MGMT promoter.

Magnetic resonance image features identify glioblastoma phenotypic subtypes with distinct molecular pathway activities

Glioblastoma (GBM) is the most common and highly lethal primary malignant brain tumor in adults. There is a dire need for easily accessible, noninvasive biomarkers that can delineate underlying molecular activities and predict response to therapy. To this end, we sought to identify subtypes of GBM, differentiated solely by quantitative magnetic resonance (MR) imaging features, that could be used for better management of GBM patients. Quantitative image features capturing the shape, texture, and edge sharpness of each lesion were extracted from MR images of 121 single-institution patients with de novo, solitary, unilateral GBM. Three distinct phenotypic "clusters" emerged in the development cohort using consensus clustering with 10,000 iterations on these image features. These three clusters--pre-multifocal, spherical, and rim-enhancing, names reflecting their image features--were validated in an independent cohort consisting of 144 multi-institution patients with similar tumor characteristics from The Cancer Genome Atlas (TCGA). Each cluster mapped to a unique set of molecular signaling pathways using pathway activity estimates derived from the analysis of TCGA tumor copy number and gene expression data with the PARADIGM (Pathway Recognition Algorithm Using Data Integration on Genomic Models) algorithm. Distinct pathways, such as c-Kit and FOXA, were enriched in each cluster, indicating differential molecular activities as determined by the image features. Each cluster also demonstrated differential probabilities of survival, indicating prognostic importance. Our imaging method offers a noninvasive approach to stratify GBM patients and also provides unique sets of molecular signatures to inform targeted therapy and personalized treatment of GBM.

ReACT Phase II trial: a critical evaluation of the use of rindopepimut plus bevacizumab to treat EGFRvIII-positive recurrent glioblastoma

Glioblastoma is the most deadly primary brain tumor in adults and has long represented a therapeutic challenge. Disease recurrence is inevitable, and the management of recurrent disease is complicated by spontaneous or induced tumor heterogeneity which confers resistance to therapy and increased oncogenicity. EGFR and the tumor-specific mutation EGFRvIII is commonly altered in glioblastoma making it an appealing therapeutic target. Immunotherapy is an emerging and promising therapeutic approach to glioma and the EGFRvIII vaccine, rindopepimut, is the first immunotherapeutic drug to enter Phase III clinical trials for glioblastoma. Rindopepimut activates a specific immune response against tumor cells harboring the EGFRvIII protein. This review evaluates the recently completed ReACT Phase II trial using rindopepimut plus bevacizumab in the setting of EGFRvIII-positive recurrent glioblastoma (Clinical Trials identifier: NCT01498328).

Broad targeting of resistance to apoptosis in cancer

Apoptosis or programmed cell death is natural way of removing aged cells from the body. Most of the anti-cancer therapies trigger apoptosis induction and related cell death networks to eliminate malignant cells. However, in cancer, de-regulated apoptotic signaling, particularly the activation of an anti-apoptotic systems, allows cancer cells to escape this program leading to uncontrolled proliferation resulting in tumor survival, therapeutic resistance and recurrence of cancer. This resistance is a complicated phenomenon that emanates from the interactions of various molecules and signaling pathways. In this comprehensive review we discuss the various factors contributing to apoptosis resistance in cancers. The key resistance targets that are discussed include (1) Bcl-2 and Mcl-1 proteins; (2) autophagy processes; (3) necrosis and necroptosis; (4) heat shock protein signaling; (5) the proteasome pathway; (6) epigenetic mechanisms; and (7) aberrant nuclear export signaling. The shortcomings of current therapeutic modalities are highlighted and a broad spectrum strategy using approaches including (a) gossypol; (b) epigallocatechin-3-gallate; (c) UMI-77 (d) triptolide and (e) selinexor that can be used to overcome cell death resistance is presented. This review provides a roadmap for the design of successful anti-cancer strategies that overcome resistance to apoptosis for better therapeutic outcome in patients with cancer.

Prognostic value of epidermal growth factor receptor amplification and EGFRvIII in glioblastoma: meta-analysis

OBJECTIVES

Epidermal growth factor receptor (EGFR) gene amplification and the EGFRvIII mutation may have prognostic value in patients with glioblastoma. This meta-analysis was to determine whether EGFR gene amplification or the EGFRvIII mutation are predictors of survival in patients with glioblastoma and anaplastic astrocytoma.

MATERIALS AND METHODS

Medline, the Cochrane Central Register of Controlled Trials, EMBASE, and Google Scholar databases were searched until July 31, 2014. Studies were selected for inclusion in the analysis if they included patients with anaplastic astrocytoma and/or glioblastoma, EGFR and/or EGFRvIII mutation status was reported, and overall survival (OS) data were reported.

RESULTS

Of 113 articles initially identified, only eight contained data with respect to the outcome of interest and were included in the meta-analysis. The number of cases ranged from 14 to 268, and the majority of patients were 60 or more years of age. There was no significant difference in OS between EGFR amplification-positive and EGFR amplification-negative glioblastoma patients (pooled hazard ratio [HR] = 1.101, 95% confidence interval [CI] 0.845, 1.434, P = 0.475) or anaplastic astrocytoma patients (pooled HR = 1.455, 95% CI 0.852, 2.482, P = 0.169). There was no significant difference in OS between EGFRvIII-positive and EGFRvIII-negative glioblastoma patients (pooled HR = 1.321, 95% CI: 0.881-1.981, P = 0.178). Significant heterogeneity existed between the studies, and the significance changed when the analysis was performed with studies removed in turn.

CONCLUSIONS

There is insufficient evidence that either EGFR amplification or the EGFRvIII mutation has prognostic value in patients with glioblastoma.

Recurrent Glioblastoma: Where we stand

Current first-line treatment regimens combine surgical resection and chemoradiation for Glioblastoma that provides a slight increase in overall survival. Age on its own should not be used as an exclusion criterion of glioblastoma multiforme (GBM) treatment, but performance should be factored heavily into the decision-making process for treatment planning. Despite aggressive initial treatment, most patients develop recurrent diseases which can be treated with re-resection, systemic treatment with targeted agents or cytotoxic chemotherapy, reirradiation, or radiosurgery. Research into novel therapies is investigating alternative temozolomide regimens, convection-enhanced delivery, immunotherapy, gene therapy, antiangiogenic agents, poly ADP ribose polymerase inhibitors, or cancer stem cell signaling pathways. Given the aggressive and resilient nature of GBM, continued efforts to better understand GBM pathophysiology are required to discover novel targets for future therapy.

Molecular Biology in Pediatric High-Grade Glioma: Impact on Prognosis and Treatment

High-grade gliomas are the main cause of death in children with brain tumours. Despite recent advances in cancer therapy, their prognosis remains poor and the treatment is still challenging. To date, surgery followed by radiotherapy and temozolomide is the standard therapy. However, increasing knowledge of glioma biology is starting to impact drug development towards targeted therapies. The identification of agents directed against molecular targets aims at going beyond the traditional therapeutic approach in order to develop a personalized therapy and improve the outcome of pediatric high-grade gliomas. In this paper, we critically review the literature regarding the genetic abnormalities implicated in the pathogenesis of pediatric malignant gliomas and the current development of molecularly targeted therapies. In particular, we analyse the impact of molecular biology on the prognosis and treatment of pediatric high-grade glioma, comparing it to that of adult gliomas.