Cediranib: profile of a novel anti-angiogenic agent in patients with glioblastoma

Efficacy of tumour-treating fields therapy in recurrent glioblastoma: A narrative review of current evidence

Recurrent Glioblastoma presents a formidable challenge in oncology due to its aggressive nature and limited treatment options. Tumour-Treating Fields (TTFields) Therapy, a novel therapeutic modality, has emerged as a promising approach to address this clinical conundrum. This review synthesizes the current evidence surrounding the efficacy of TTFields Therapy in the context of recurrent Glioblastoma. Diverse academic databases were explored to identify relevant studies published within the last decade. Strategic keyword selection facilitated the inclusion of studies focusing on TTFields Therapy's efficacy, treatment outcomes, and patient-specific factors. The review reveals a growing body of evidence suggesting the potential clinical benefits of TTFields Therapy for patients with recurrent Glioblastoma. Studies consistently demonstrate its positive impact on overall survival (OS) and progression-free survival (PFS). The therapy's safety profile remains favorable, with mild to moderate skin reactions being the most commonly reported adverse events. Our analysis highlights the importance of patient selection criteria, with emerging biomarkers such as PTEN mutation status influencing therapy response. Additionally, investigations into combining TTFields Therapy with other treatments, including surgical interventions and novel approaches, offer promising avenues for enhancing therapeutic outcomes. The synthesis of diverse studies underscores the potential of TTFields Therapy as a valuable addition to the armamentarium against recurrent Glioblastoma. The narrative review comprehensively explains the therapy's mechanisms, clinical benefits, adverse events, and future directions. The insights gathered herein serve as a foundation for clinicians and researchers striving to optimize treatment strategies for patients facing the challenging landscape of recurrent Glioblastoma.

A patent perspective of antiangiogenic agents

INTRODUCTION

Angiogenesis plays a crucial role in the development of numerous vascular structures and is involved in a variety of physiologic and pathologic processes, including psoriasis, diabetic retinopathy, and especially cancer. By obstructing the process of angiogenesis, these therapies effectively inhibit the progression of the disease. Consequently, anti-angiogenic agents were subsequently developed.

AREAS COVERED

This review provides a comprehensive summary of the anti-angiogenic inhibitors developed in the past five years in terms of chemical structure, biochemical/pharmacological activity and potential clinical applications. A literature search was conducted using utilizing the databases Web of Science, SciFinder and PubMed with the key word 'anti-angiogenic agents' and 'angiogenesis inhibitor.'

EXPERT OPINION

This is despite the fact that the concept of antiangiogenesis has been proposed for more than 50 years and angiogenesis inhibitors are extensively employed in clinical practice. However, significant challenges continue to confront them. In recent years, there has been a significant increase in the number of patents focusing on angiogenesis inhibitors. These patents aim to enhance the selectivity of drugs against VEGF/VEGFR, explore new targets to overcome drug resistance, and explore potential drug combinations, thereby expanding the therapeutic possibilities in this field.

Exploring the Past, Present, and Future of Anti-Angiogenic Therapy in Glioblastoma

Glioblastoma, a WHO grade IV astrocytoma, constitutes approximately half of malignant tumors of the central nervous system. Despite technological advancements and aggressive multimodal treatment, prognosis remains dismal. The highly vascularized nature of glioblastoma enables the tumor cells to grow and invade the surrounding tissue, and vascular endothelial growth factor-A (VEGF-A) is a critical mediator of this process. Therefore, over the past decade, angiogenesis, and more specifically, the VEGF signaling pathway, has emerged as a therapeutic target for glioblastoma therapy. This led to the FDA approval of bevacizumab, a monoclonal antibody designed against VEGF-A, for treatment of recurrent glioblastoma. Despite the promising preclinical data and its theoretical effectiveness, bevacizumab has failed to improve patients' overall survival. Furthermore, several other anti-angiogenic agents that target the VEGF signaling pathway have also not demonstrated survival improvement. This suggests the presence of other compensatory angiogenic signaling pathways that surpass the anti-angiogenic effects of these agents and facilitate vascularization despite ongoing VEGF signaling inhibition. Herein, we review the current state of anti-angiogenic agents, discuss potential mechanisms of anti-angiogenic resistance, and suggest potential avenues to increase the efficacy of this therapeutic approach.

Cystic Glioblastoma: A Mimicker of Infection? A Case Report and Literature Review

Glioblastoma multiforme (GBM) is the most frequent malignant and aggressive type of glioma. Most cases of GBM present as a single solitary solid tumor; however, there are rare instances in which it may present as a cystic lesion. Here, we report an even rarer case of GBM presenting as bilateral multicystic lesions, mimicking infectious etiology. Our case highlights the importance of identifying clinical features of cystic GBM to ensure early diagnosis and treatment. A literature review was conducted in PubMed, looking at the common characteristics and treatment options for cystic GBM.

Rh(III)-Catalyzed Tandem Reaction Access to (Quinazolin-2-yl)methanone Derivatives from 2,1-Benzisoxazoles and α-Azido Ketones

A Rh(III)-catalyzed tandem reaction for the synthesis of (quinazolin-2-yl)methanone derivatives has been explored from 2,1-benzisoxazoles and α-azido ketones. The transformation involves Rh(III)-catalyzed denitrogenation of α-azido ketones, aza-[4 + 2] cycloaddition, ring opening, and dehydration aromatization processes. Notably, the aza-[4 + 2] cycloaddition of an imine rhodium complex intermediate with 2,1-benzisoxazoles is the key to this reaction.

Repurposing therapeutics for malignant pleural mesothelioma (MPM) - Updates on clinical translations and future outlook

INTRODUCTION

Malignant pleural mesothelioma (MPM) is a rare malignancy affecting the mesothelial cells in the pleural lining surrounding the lungs. First approved chemotherapy against MPM was a platinum/antifolate (cisplatin/pemetrexed) (2003). Since then, no USFDA approvals have gone through for small molecules as these molecules have not been proven to be therapeutically able in later stages of clinical studies. An alternative to conventional chemotherapy can be utilization of monoclonal antibodies, which are proven to improve patient survival significantly as compared to conventional chemotherapy (Nivolumab + Ipilimumab, 2020).

AREA COVERED

Drug repurposing has been instrumental in drug discovery for rare diseases such as MPM and multiple repositioned small molecule therapies and immunotherapies are currently being tested for its applicability in MPM management. This article summarizes essential breakthroughs along the pre-clinical and clinical developmental stages of small molecules and monoclonal antibodies for MPM management.

EXPERT OPINION

For rare diseases such as malignant pleural mesothelioma, a drug repurposing strategy can be adapted as it eases the financial burden on pharmaceutical companies along with fast-tracking development. With the rise of multiple small molecule repurposed therapies and innovations in localized treatment, MPM therapeutics are bound to be more effective in this decade.

Topical noninvasive retinal drug delivery of a tyrosine kinase inhibitor: 3% cediranib maleate cyclodextrin nanoparticle eye drops in the rabbit eye

PURPOSE

Tyrosine kinase inhibitors inhibit VEGF receptors. If delivered to the retina, they might inhibit oedema and neovascularization such as in age-related macular degeneration and diabetic retinopathy. The aim of this study was to formulate cediranib maleate, a potent VEGF inhibitor, as γ-cyclodextrin nanoparticle eye drops and measure the retinal delivery and overall ocular pharmacokinetics after a single-dose administration in rabbits.

METHODS

A novel formulation technology with 3% cediranib maleate as γ-cyclodextrin micro-suspension was prepared by autoclaving method. Suitable stabilizers were tested for heat-stable eye drops. The ophthalmic formulation was topically applied to one eye in rabbits. The pharmacokinetics in ocular tissues, tear film and blood samples were studied at 1, 3 and 6 hr after administration.

RESULTS

γ-cyclodextrin formed complex with cediranib maleate. The formation of γ-cyclodextrin nanoparticles occurred in concentrated complexing media. Combined stabilizers prevented the degradation of drug during the autoclaving process. Three hours after administration of the eye drops, treated eyes showed cediranib levels of 737 ± 460 nM (mean ± SD) in the retina and 10 ± 6 nM in the vitreous humour.

CONCLUSIONS

Cediranib maleate in γ-cyclodextrin nanoparticles were stable to heat in presence of stabilizers. The drug as eye drops reached the retina in concentrations that are more than 100 times higher than the 0.4 nM IC₅₀ value reported for the VEGF type-II receptor and thus, presumably, above therapeutic level. These results suggest that γ-cyclodextrin-based cediranib maleate eye drops deliver effective drug concentrations to the retina in rabbits after a single-dose administration.

Addressing the obstacles of CAR T cell migration in solid tumors: wishing a heavy traffic

Chimeric antigen receptor T cell (CAR-T) therapy has been recognized as one of the most prosperous treatment options against certain blood-based malignancies. However, the same clinical and commercial success have been out of range in the case of solid tumors. The main contributing factor in this regard is the hostile environment the tumor cells impose that results in the exhaustion of immune effector cells alongside the abrogation of their infiltration capacity. The discovery of the underlying mechanisms and the development of reliable counterstrategies to overcome the inaccessibility of CAR-Ts to their target cells might correlate with encouraging clinical outcomes in advanced solid tumors. Here, we highlight the successive physical and metabolic barriers that systemically administered CAR-Ts face on their journey toward their target cells. Moreover, we propose meticulously-devised countertactics and combination therapies that can be applied to maximize the therapeutic benefits of CAR-T therapies against solid tumors.

Glioblastoma pharmacotherapy: A multifaceted perspective of conventional and emerging treatments (Review)

Due to its localisation, rapid onset, high relapse rate and resistance to most currently available treatment methods, glioblastoma multiforme (GBM) is considered to be the deadliest type of all gliomas. Although surgical resection, chemotherapy and radiotherapy are among the therapeutic strategies used for the treatment of GBM, the survival rates achieved are not satisfactory, and there is an urgent need for novel effective therapeutic options. In addition to single-target therapy, multi-target therapies are currently under development. Furthermore, drugs are being optimised to improve their ability to cross the blood-brain barrier. In the present review, the main strategies applied for GBM treatment in terms of the most recent therapeutic agents and approaches that are currently under pre-clinical and clinical testing were discussed. In addition, the most recently reported experimental data following the testing of novel therapies, including stem cell therapy, immunotherapy, gene therapy, genomic correction and precision medicine, were reviewed, and their advantages and drawbacks were also summarised.

Cediranib, a pan-inhibitor of vascular endothelial growth factor receptors, inhibits proliferation and enhances therapeutic sensitivity in glioblastoma cells

AIMS

Glioblastoma (GB) is the most aggressive type of brain tumor. Rapid progression, active angiogenesis, and therapy resistance are major reasons for its high mortality. Elevated expression of members of the vascular endothelial growth factor (VEGF) family suggests that anti-VEGF therapies may be potent anti-glioma therapeutic approaches. Here, we evaluated the anti-tumor activity of cediranib, a pan inhibitor of the VEGF receptors, on GB cells.

MATERIALS AND METHODS

Anti-proliferative effects of cediranib were determined using MTT, crystal-violet staining, clonogenic and anoikis resistance assays. Apoptosis induction was assessed by Annexin V/PI staining and Western blot analysis and aggressive abilities of GB cells were investigated using cell migration/invasion assays and zymography. Small-interfering RNA (siRNA)-mediated Knockdown was used to study resistance mechanisms. The anti-proliferative and apoptotic effects of cediranib in combination with radiotherapy, temozolomide, bevacizumab were also evaluated using MTT, Annexin V/PI staining and Western blot analysis for cleaved PARP-1.

KEY FINDINGS

Cediranib reduced GB cell proliferation, induced apoptotic cell death and inhibited the aggressive abilities of GB cells. Cediranib synergistically increased the anti-proliferative and apoptotic effects of radiotherapy and bevacizumab and augmented the sensitivity of GB cells to temozolomide chemotherapy. In addition, knockdown of MET and AKT potentiated cediranib sensitivity in cediranib-resistant GB cells.

SIGNIFICANCE

These findings suggest that cediranib, alone or in combination with other therapeutics, is a promising strategy for the treatment of GB and provide a rationale for further investigation of the therapeutic potential of cediranib for the treatment of this fatal malignancy.

Therapeutic targeting of membrane-associated proteins in central nervous system tumors

The activity of the most complex system, the central nervous system (CNS) is profoundly regulated by a huge number of membrane-associated proteins (MAP). A minor change stimulates immense chemical changes and the elicited response is organized by MAP, which acts as a receptor of that chemical or channel enabling the flow of ions. Slight changes in the activity or expression of these MAPs lead to severe consequences such as cognitive disorders, memory loss, or cancer. CNS tumors are heterogeneous in nature and hard-to-treat due to random mutations in MAPs; like as overexpression of EGFRvIII/TGFβR/VEGFR, change in adhesion molecules α5β3 integrin/SEMA3A, imbalance in ion channel proteins, etc. Extensive research is under process for developing new therapeutic approaches using these proteins such as targeted cytotoxic radiotherapy, drug-delivery, and prodrug activation, blocking of receptors like GluA1, developing viral vector against cell surface receptor. The combinatorial approach of these strategies along with the conventional one might be more potential. Henceforth, our review focuses on in-depth analysis regarding MAPs aiming for a better understanding for developing an efficient therapeutic approach for targeting CNS tumors.

A Drug Screening Pipeline Using 2D and 3D Patient-Derived In Vitro Models for Pre-Clinical Analysis of Therapy Response in Glioblastoma

Glioblastoma is one of the most common and lethal types of primary brain tumor. Despite aggressive treatment with chemotherapy and radiotherapy, tumor recurrence within 6-9 months is common. To overcome this, more effective therapies targeting cancer cell stemness, invasion, metabolism, cell death resistance and the interactions of tumor cells with their surrounding microenvironment are required. In this study, we performed a systematic review of the molecular mechanisms that drive glioblastoma progression, which led to the identification of 65 drugs/inhibitors that we screened for their efficacy to kill patient-derived glioma stem cells in two dimensional (2D) cultures and patient-derived three dimensional (3D) glioblastoma explant organoids (GBOs). From the screening, we found a group of drugs that presented different selectivity on different patient-derived in vitro models. Moreover, we found that Costunolide, a TERT inhibitor, was effective in reducing the cell viability in vitro of both primary tumor models as well as tumor models pre-treated with chemotherapy and radiotherapy. These results present a novel workflow for screening a relatively large groups of drugs, whose results could lead to the identification of more personalized and effective treatment for recurrent glioblastoma.

Lessons learned from contemporary glioblastoma randomized clinical trials through systematic review and network meta-analysis: part 2 recurrent glioblastoma

BACKGROUND

There exists no consensus standard of treatment for patients with recurrent glioblastoma (GB). Here we used a network meta-analysis on treatments from randomized control trials (RCTs) to assess the effect on overall survival (OS) and progression-free survival (PFS) to determine if any consensus treatment can be determined for recurrent GB.

METHODS

We included all recurrent GB RCTs with at least 20 patients in each arm, and for whom patients underwent standard of care at the time of their GB initial diagnosis. Our primary outcome was OS, with secondary outcomes including PFS and adverse reactions. Hazard ratio (HR) and its 95% confidence interval (CI) of the comparison of study arms regarding OS and PFS were extracted from each paper. For comparative efficacy analysis, we utilized a frequentist network meta-analysis, an extension of the classic pair-wise meta-analysis. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses.

RESULTS

Fifteen studies were included representing 29 separate treatment arms and 2194 patients. In our network meta-analysis, combination treatment with tumor-treating field and Vascular endothelial growth factor (VEGF) inhibitor ranked first in improving OS (P = .80). Concomitant anti-VEGF and Lomustine treatment was superior to Lomustine alone for extending PFS (HR 0.57, 95% CI 0.41-0.79) and ranked first in improving PFS compared to other included treatments (P = .86).

CONCLUSIONS

Our analysis highlights the numerous studies performed on recurrent GB, with no proven consensus treatment that is superior to the current SOC. Intertrial heterogeneity precludes drawing strong conclusions, and confidence analysis was low to very low. Further confirmation by future trials is recommended for our exploratory results.

Increased epithelial membrane protein 2 expression in glioblastoma after treatment with bevacizumab

Background

Antiangiogenic therapy with bevacizumab has failed to provide substantial gains in overall survival. Epithelial membrane protein 2 (EMP2) is a cell surface protein that has been previously shown to be expressed in glioblastoma, correlate with poor survival, and regulate neoangiogenesis in cell lines. Thus, the relationship between bevacizumab and EMP2 was investigated.

Methods

Tumor samples were obtained from 12 patients with newly diagnosed glioblastoma at 2 time points: (1) during the initial surgery and (2) during a subsequent surgery following disease recurrence post-bevacizumab treatment. Clinical characteristics and survival data from these patients were collected, and tumor samples were stained for EMP2 expression. The IVY Glioblastoma Atlas Project database was used to evaluate EMP2 expression levels in 270 samples by differing histological areas of the tumor.

Results

Patients with high EMP2 staining at initial diagnosis had decreased progression-free and overall survival after bevacizumab (median progression-free survival 4.6 months vs 5.9 months; log-rank P = .076 and overall survival 7.7 months vs 14.4 months; log-rank P = .011). There was increased EMP2 staining in samples obtained after bevacizumab treatment in both unpaired (mean H-score 2.31 vs 1.76; P = .006) and paired analyses (mean difference 0.571; P = .019). This expression increase correlated with length of bevacizumab therapy (R ²  = 0.449; Pearson P = .024).

Conclusions

Bevacizumab treatment increased EMP2 protein expression. This increase in EMP2 correlated with reduced mean survival time post-bevacizumab therapy. We hypothesize a role of EMP2 in clinical bevacizumab resistance and as a potential antiangiogenic therapeutic target in glioblastoma.

Cediranib, an inhibitor of vascular endothelial growth factor receptor kinases, inhibits proliferation and invasion of prostate adenocarcinoma cells

Prostate Cancer is the second cause of cancer-related death in men and development of metastatic castration-resistant prostate cancer (mCRPC) is the major reason for its high mortality rate. Despite various treatments, all patients succumb to resistant disease, suggesting that there is a pressing need for novel and more efficacious treatments. Members of the vascular endothelial growth factor (VEGF) family play key roles in the tumorigenesis of mCRPC, indicating that VEGF-targeted therapies may have potential anti-tumor efficacy in this malignancy. However, due to compensatory activation of other family members, clinical trials with single-targeted VEGF inhibitors were discouraging. Here, we determined the anti-neoplastic activity of Cediranib, a pan-VEGF receptor inhibitor, in the mCRPC cell lines. Anti-growth effects of Cediranib were studied by MTT and BrdU cell proliferation assays and crystal violet staining. Annexin V/PI, radiation therapy and cell motility assays were carried out to examine the effects of Cediranib on apoptosis, radio-sensitivity and cell motility. Quantitative reverse transcription-PCR (qRT-PCR) and Western blot analyses were conducted to determine the molecular mechanisms underlying the anti-tumor activity of Cediranib. Cediranib decreased cell viability and induced apoptosis via inhibition of the anti-apoptotic proteins. Combination with Cediranib synergistically increased Docetaxel sensitivity and potentiated the effects of radiation therapy. Furthermore, Cediranib impaired cell motility via decrease in the expression of the epithelial-to-mesenchymal transition markers. These findings suggest that Cediranib may have anti-tumor activity in mCRPC cells and warrant further investigation on the therapeutic activity of this pan-VEGF receptor inhibitor in mCRPC.

Overcoming the Blood-Brain Barrier: Successes and Challenges in Developing Nanoparticle-Mediated Drug Delivery Systems for the Treatment of Brain Tumours

High-grade gliomas are still characterized by a poor prognosis, despite recent advances in surgical treatment. Chemotherapy is currently practiced after surgery, but its efficacy is limited by aspecific toxicity on healthy cells, tumour cell chemoresistance, poor selectivity, and especially by the blood–brain barrier (BBB). Thus, despite the large number of potential drug candidates, the choice of effective chemotherapeutics is still limited to few compounds. Malignant gliomas are characterized by high infiltration and neovascularization, and leaky BBB (the so-called blood–brain tumour barrier); surgical resection is often incomplete, leaving residual cells that are able to migrate and proliferate. Nanocarriers can favour delivery of chemotherapeutics to brain tumours owing to different strategies, including chemical stabilization of the drug in the bloodstream; passive targeting (because of the leaky vascularization at the tumour site); inhibition of drug efflux mechanisms in endothelial and cancer cells; and active targeting by exploiting carriers and receptors overexpressed at the blood–brain tumour barrier. Within this concern, a suitable nanomedicine-based therapy for gliomas should not be limited to cytotoxic agents, but also target the most important pathogenetic mechanisms, including cell differentiation pathways and angiogenesis. Moreover, the combinatorial approach of cell therapy plus nanomedicine strategies can open new therapeutical opportunities. The major part of attempted preclinical approaches on animal models involves active targeting with protein ligands, but, despite encouraging results, a few number of nanomedicines reached clinical trials, and most of them include drug-loaded nanocarriers free of targeting ligands, also because of safety and scalability concerns.

Clinical Pharmacokinetics and Pharmacodynamics of Cediranib

Cediranib potently and selectively inhibits all three vascular endothelial growth factor receptors (VEGFR-1, -2 and -3), and clinical studies have shown that it is effective in patients with ovarian cancer at a dose of 20 mg/day. Cediranib is absorbed moderately slowly; a high-fat meal reduced the cediranib area under the plasma concentration-time curve (AUC) by 24% and maximum plasma concentration (C _max) by 33%. Cediranib binds to serum albumin and α1-acid glycoprotein; protein binding in human plasma is approximately 95%. The cediranib AUC and C _max increase proportionally with dose from 0.5 to 60 mg, and cediranib has linear pharmacokinetics (PK) over time. Cediranib is metabolized via flavin-containing monooxygenase 1 and 3 (FMO1, FMO3) and uridine 5'-diphospho-glucuronosyltransferase (UGT) 1A4. Cediranib and its metabolites are mainly excreted in faeces (59%), with <1% of unchanged drug being excreted in urine. The apparent oral clearance is moderate and the mean terminal half-life is 22 h. Cediranib is a substrate of multidrug resistance-1 (MDR1) protein (also known as P-glycoprotein [P-gp]). Coadministration with ketoconazole, a potent P-gp inhibitor, increases cediranib AUC at steady-state (AUC_ss) in patients by 21%, while coadministration with rifampicin, a potent inducer of P-gp, decreases cediranib AUC_ss by 39%. Administration of cediranib with chemotherapies demonstrated minimal PK impact on each other. No dose adjustment is recommended for patients with mild or moderate hepatic or renal impairment, and no dose adjustment is needed on the basis of age and body weight. A pooled analysis at doses of 0.5-60 mg showed no significant increase in QTc intervals. Increases in blood pressure and the incidence of diarrhoea were associated with increased cediranib dose and systemic exposure.

High-Dose Compound Heat Map for 3D-Cultured Glioblastoma Multiforme Cells in a Micropillar and Microwell Chip Platform

Glioblastoma multiforme (GBM) is recognized as the most common and lethal form of central nervous system cancer. To cure GBM patients, many target-specific chemotherapeutic agents have been developing. However, 2D monolayer cell-based toxicity and efficacy tests did not efficiently screen agents due to the pool reflection of in vivo microenvironments (cell-to-cell and cell-to-extracellular matrix interaction). In this study, we used a 3D cell-based, high-throughput screening method reflecting the microenvironments using a micropillar and microwell chip platform to draw a high-dose heat map of the cytotoxicity and efficacy of 70 compounds, with two DMSO controls. Moreover, the high-dose heat map model compared the responses of four 3D-cultured patient-derived GBM cells and astrocytes to high dosages of compounds with respect to efficacy and cytotoxicity, respectively, to discern the most efficacious drug for GBM. Among the 70 compounds tested, cediranib (a potent inhibitor of vascular endothelial growth factor (VEGF) receptor tyrosine kinases) exhibited the lowest cytotoxicity to astrocytes and high efficacy to GBM cells in a high-dose heat map model.

Recombinant interleukin-1 receptor antagonist conjugated to superparamagnetic iron oxide nanoparticles for theranostic targeting of experimental glioblastoma

Cerebral edema commonly accompanies brain tumors and contributes to neurologic symptoms. The role of the interleukin-1 receptor antagonist conjugated to superparamagnetic iron oxide nanoparticles (SPION-IL-1Ra) was assessed to analyze its anti-edemal effect and its possible application as a negative contrast enhancing agent for magnetic resonance imaging (MRI). Rats with intracranial C6 glioma were intravenously administered at various concentrations of IL-1Ra or SPION-IL-1Ra. Brain peritumoral edema following treatment with receptor antagonist was assessed with high-field MRI. IL-1Ra administered at later stages of tumor progression significantly reduced peritumoral edema (as measured by MRI) and prolonged two-fold the life span of comorbid animals in a dose-dependent manner in comparison to control and corticosteroid-treated animals (P < .001). Synthesized SPION-IL-1Ra conjugates had the properties of negative contrast agent with high coefficients of relaxation efficiency. In vitro studies of SPION-IL-1Ra nanoparticles demonstrated high intracellular incorporation and absence of toxic influence on C6 cells and lymphocyte viability and proliferation. Retention of the nanoparticles in the tumor resulted in enhanced hypotensive T2-weighted images of glioma, proving the application of the conjugates as negative magnetic resonance contrast agents. Moreover, nanoparticles reduced the peritumoral edema confirming the therapeutic potency of synthesized conjugates. SPION-IL-1Ra nanoparticles have an anti-edemal effect when administered through a clinically relevant route in animals with glioma. The SPION-IL-1Ra could be a candidate for theranostic approach in neuro-oncology both for diagnosis of brain tumors and management of peritumoral edema.

Acute vascular response to cediranib treatment in human non-small-cell lung cancer xenografts with different tumour stromal architecture

•

We studied cediranib, a VEGFR tyrosine kinase inhibitor in lung cancer xenografts.

•

Gadolinium-enhanced DCE-MRI was used to study acute vascular responses.

•

Acute vascular response was associated with tumour stromal architecture.

•

Tumour growth inhibition by cediranib was linked to acute vascular response.

•

Acute vascular changes are a potential predictive marker of response to cediranib.

Objectives

Tumours can be categorised based on their stromal architecture into tumour vessel and stromal vessel phenotypes, and the phenotypes have been suggested to define tumour response to chronic treatment with a VEGFR2 antibody. However, it is unclear whether the vascular phenotypes of tumours associate with acute vascular response to VEGFR tyrosine kinase inhibitors (TKI), or whether the early changes in vascular function are associated with subsequent changes in tumour size. This study was sought to address these questions by using xenograft models of human non-small cell lung cancer (NSCLC) representing stromal vessel phenotype (Calu-3) and tumour vessel phenotype (Calu-6), respectively.

Methods

For dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), nude mice bearing established Calu-3 or Calu-6 xenografts were treated with a potent pan-VEGFR TKI, cediranib (6 mg/kg), at 0 h and 22 h. DCE-MRI was performed 2 h before the first dose and 2 h after the second dose of cediranib to examine acute changes in tumour vessel perfusion. Tumours were harvested for hypoxia detection by CA9 immunohistochemistry. For tumour growth study, mice carrying established Calu-3 or Calu-6 tumours were treated with cediranib once daily for 5 days.

Results

Twenty-four hours after cediranib administration, the perfusion of Calu-3 tumours was markedly reduced, with a significant increase in hypoxia. In contrast, neither perfusion nor hypoxia was significantly affected in Calu-6 tumours. Tumour regressions were induced in Calu-3 xenografts, but not in Calu-6 xenografts, although there was a trend towards tumour growth inhibition after 5 days of cediranib treatment.

Conclusion

These findings suggest that tumour stromal architecture may associate with acute tumour vascular response to VEGFR TKI, and this acute tumour vascular response may be a promising early predictive marker of response to VEGFR TKI in NSCLC.

Contributions to drug resistance in glioblastoma derived from malignant cells in the sub-ependymal zone

Glioblastoma, the most common and aggressive adult brain tumor, is characterized by extreme phenotypic diversity and treatment failure. Through fluorescence-guided resection, we identified fluorescent tissue in the sub-ependymal zone (SEZ) of patients with glioblastoma. Histologic analysis and genomic characterization revealed that the SEZ harbors malignant cells with tumor-initiating capacity, analogous to cells isolated from the fluorescent tumor mass (T). We observed resistance to supramaximal chemotherapy doses along with differential patterns of drug response between T and SEZ in the same tumor. Our results reveal novel insights into glioblastoma growth dynamics, with implications for understanding and limiting treatment resistance.

Efficacy of motesanib diphosphate in non-small-cell lung cancer

INTRODUCTION

Angiogenesis plays a crucial role in the proliferation and in the metastatic spread of tumour cells. Several agents with anti-angiogenic activity have been tested in advanced non-small-cell lung cancer (NSCLC) patients. Motesanib (AMG 706) is a promising anti-angiogenic multi-targeted tyrosine kinase inhibitor (TKI), which has been investigated as a monotherapy or in combination with chemotherapy, in several types of cancer.

AREAS COVERED

We have reviewed the literature, and we have presented the results of clinical trials that have investigated the administration of motesanib in advanced NSCLC patients.

EXPERT OPINION

Encouraging results have been described with the administration of motesanib as first-line treatment in combination with carboplatin and paclitaxel in Asian patients with non-squamous advanced NSCLC. Further studies are needed in order to identify the predictive biomarkers of response and to select patients who may benefit from this anti-angiogenic treatment.

Essential role of AKT in tumor cells addicted to FGFR

Tumor cells with genetic amplifications or mutations in the fibroblast growth factor receptor (FGFR) family are often addicted to FGFR and heavily dependent on its signaling to survive. Although it is critical to understand which signaling pathway downstream of FGFR plays an essential role to guide the research and development of FGFR inhibitors, it has remained unclear partly because the tool compounds used in the literature also hit many other kinases, making the results difficult to interpret. With the development of a potent FGFR-specific inhibitor, BGJ398, we are now able to dissect various pathways with low drug concentrations to minimize multiple-target effects. Importantly, here, we show that inhibition of FGFR signaling by BGJ398 leads to only transient inhibition of ERK1/2 phosphorylation, whereas the inhibitory effect on AKT phosphorylation is sustainable, indicating that AKT, not ERK as commonly believed, serves as an appropriate pharmacodynamic biomarker for BGJ398. Although AKT inhibition by a pan-PI3K inhibitor alone has almost no effect on cell growth, heterologous expression of myr-AKT, an active form of AKT, rescues BGJ398-mediated suppression of tumor cell proliferation. These results indicate that AKT is an essential component downstream of FGFR. Finally, combination of the FGFR inhibitor BGJ398 with rapamycin significantly inhibits AKT phosphorylation and enhances their antiproliferative effects in FGFR-addicted cells, suggesting an effective combination strategy for clinical development of FGFR inhibitors.

Distinct phenotypic differences associated with differential amplification of receptor tyrosine kinase genes at 4q12 in glioblastoma

Gene amplification at chromosome 4q12 is a common alteration in human high grade gliomas including glioblastoma, a CNS tumour with consistently poor prognosis. This locus harbours the known oncogenes encoding the receptor tyrosine kinases PDGFRA, KIT, and VEGFR2. These receptors are potential targets for novel therapeutic intervention in these diseases, with expression noted in tumour cells and/or associated vasculature. Despite this, a detailed assessment of their relative contributions to different high grade glioma histologies and the underlying heterogeneity within glioblastoma has been lacking. We studied 342 primary high grade gliomas for individual gene amplification using specific FISH probes, as well as receptor expression in the tumour and endothelial cells by immunohistochemistry, and correlated our findings with specific tumour cell morphological types and patterns of vasculature. We identified amplicons which encompassed PDGFRA only, PDGFRA/KIT, and PDGFRA/KIT/VEGFR2, with distinct phenotypic correlates. Within glioblastoma specimens, PDGFRA amplification alone was linked to oligodendroglial, small cell and sarcomatous tumour cell morphologies, and rare MGMT promoter methylation. A younger age at diagnosis and better clinical outcome in glioblastoma patients is only seen when PDGFRA and KIT are co-amplified. IDH1 mutation was only found when all three genes are amplified; this is a subgroup which also harbours extensive MGMT promoter methylation. Whilst PDGFRA amplification was tightly linked to tumour expression of the receptor, this was not the case for KIT or VEGFR2. Thus we have identified differential patterns of gene amplification and expression of RTKs at the 4q12 locus to be associated with specific phenotypes which may reflect their distinct underlying mechanisms.

Current strategies for inhibiting FGFR activities in clinical applications: opportunities, challenges and toxicological considerations

Aberrations in fibroblast growth factor receptor (FGFR) signaling are instrumental to the pathophysiology of several malignancies and disorders. Hence, FGFR inhibitors are explored in therapeutics with early candidates developed as competitors for the ATP-binding pocket in the kinase domain. More recent programs yielded compounds of diverse scaffolds with alternative binding modes. Concurrently, monoclonal antibodies and peptide-based agents provide independent options for clinical development. Notwithstanding this rapid progress, we contemplate the toxicological impact of FGFR inhibition based on the defined role of FGFR family members in physiology and homeostasis. The high homology among FGFR1-4 and also with other kinase subfamilies creates an additional challenge in developing selective inhibitors. It orchestrates an ongoing conundrum of moderating a balance between synergism through multitargeting kinase inhibition and minimizing off-target toxicities.

Phase II clinical trial of cediranib in patients with metastatic castration-resistant prostate cancer

OBJECTIVE

To assess the efficacy and toxicity of cediranib, a highly potent inhibitor of vascular endothelial growth factor receptor tyrosine kinases, in patients with metastatic castration-resistant prostate cancer (CRPC) previously treated with docetaxel-based therapy.

PATIENTS AND METHODS

The study used a Simon two-stage trial design, which required at least two of 12 patients in the first cohort to be progression-free at 6 months. We enrolled a total of 35 evaluable patients who all received cediranib 20 mg orally daily. In a second cohort, 23 additional patients received prednisone 10 mg daily with cediranib. Endpoints included tumour response, progression-free survival (PFS), overall survival (OS), vascular permeability via dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and toxicity.

RESULTS

A total of 59 patients were enrolled, of whom 67% had received two or more previous chemotherapy regimens. Six of 39 patients with measurable disease had confirmed partial responses and one had an unconfirmed partial response. At 6 months, 43.9% of patients were progression-free; the median PFS and OS periods for all patients were 3.7 months and 10.1 months, respectively. We found that the DCE-MRI variables baseline transport constant (Ktrans ) and rate constant at day 28 were significantly associated with PFS in univariate analyses, but only baseline Ktrans remained significant when considered jointly. The most frequent toxicities were hypertension, fatigue, anorexia and weight loss; the addition of prednisone reduced the incidence of constitutional toxicities.

CONCLUSION

This study demonstrated that cediranib was generally well tolerated with some anti-tumour activity in highly pretreated patients with metastatic CRPC who had progressive disease after docetaxel-based therapy.

Response of HT29 colorectal xenograft model to cediranib assessed with 18 F-fluoromisonidazole positron emission tomography, dynamic contrast-enhanced and diffusion-weighted MRI

Cediranib is a small-molecule pan-vascular endothelial growth factor receptor inhibitor. The tumor response to short-term cediranib treatment was studied using dynamic contrast-enhanced and diffusion-weighted MRI at 7 T, as well as (18) F-fluoromisonidazole positron emission tomography and histological markers. Rats bearing subcutaneous HT29 human colorectal tumors were imaged at baseline; they then received three doses of cediranib (3 mg/kg per dose daily) or vehicle (dosed daily), with follow-up imaging performed 2 h after the final cediranib or vehicle dose. Tumors were excised and evaluated for the perfusion marker Hoechst 33342, the endothelial cell marker CD31, smooth muscle actin, intercapillary distance and tumor necrosis. Dynamic contrast-enhanced MRI-derived parameters decreased significantly in cediranib-treated tumors relative to pretreatment values [the muscle-normalized initial area under the gadolinium concentration curve decreased by 48% (p=0.002), the enhancing fraction by 43% (p=0.003) and K(trans) by 57% (p=0.003)], but remained unchanged in controls. No change between the pre- and post-treatment tumor apparent diffusion coefficients in either the cediranib- or vehicle-treated group was observed over the course of this study. The (18) F-fluoromisonidazole mean standardized uptake value decreased by 33% (p=0.008) in the cediranib group, but showed no significant change in the control group. Histological analysis showed that the number of CD31-positive vessels (59 per mm(2) ), the fraction of smooth muscle actin-positive vessels (80-87%) and the intercapillary distance (0.17 mm) were similar in cediranib- and vehicle-treated groups. The fraction of perfused blood vessels in cediranib-treated tumors (81 ± 7%) was lower than that in vehicle controls (91 ± 3%, p=0.02). The necrotic fraction was slightly higher in cediranib-treated rats (34 ± 12%) than in controls (26 ± 10%, p=0.23). These findings suggest that short-term treatment with cediranib causes a decrease in tumor perfusion/permeability across the tumor cross-section, but changes in vascular morphology, vessel density or tumor cellularity are not manifested at this early time point.

Overcoming resistance to antiangiogenic therapies

The concept of targeting new blood vessel formation, or angiogenesis, in tumors is an important advancement in cancer therapy, resulting, in part, from the development of such biologic agents as bevacizumab, a monoclonal antibody directed against vascular endothelial growth factor (VEGF)-A. The rationale for antiangiogenic therapy is based on the hypothesis that if tumors are limited in their capacity to obtain a new blood supply, so too is their capacity for growth and metastasis. Additional evidence suggests that pruning and/or "normalization" of irregular tumor vasculature and reduction of hypoxia may facilitate greater access of cytotoxic chemotherapy (CT) to the tumor. Indeed, for metastatic colorectal cancer, bevacizumab in combination with established CT regimens has efficacy superior to that of CT alone. Despite ~2-month longer progression-free and overall survival times than with CT alone, patients still progress, possibly because of alternative angiogenic "escape" pathways that emerge independent of VEGF-A, or are driven by hypoxic stress on the tumor. Other VEGF family members may contribute to resistance, and many factors that contribute to the regulation of tumor angiogenesis function as part of a complex network, existing in different concentrations and spatiotemporal gradients and producing a wide range of biologic responses. Integrating these concepts into the design and evaluation of new antiangiogenic therapies may help overcome resistance mechanisms and allow for greater efficacy over longer treatment periods.

Glioblastoma: therapeutic challenges, what lies ahead

Glioblastoma (GBM) is one of the most aggressive human cancers. Despite current advances in multimodality therapies, such as surgery, radiotherapy and chemotherapy, the outcome for patients with high grade glioma remains fatal. The knowledge of how glioma cells develop and depend on the tumor environment might open opportunities for new therapies. There is now a growing awareness that the main limitations in understanding and successfully treating GBM might be bypassed by the identification of a distinct cell type that has defining properties of somatic stem cells, as well as cancer-initiating capacity - brain tumor stem cells, which could represent a therapeutic target. In addition, experimental studies have demonstrated that the combination of antiangiogenic therapy, based on the disruption of tumor blood vessels, with conventional chemotherapy generates encouraging results. Emerging reports have also shown that microglial cells can be used as therapeutic vectors to transport genes and/or substances to the tumor site, which opens up new perspectives for the development of GBM therapies targeting microglial cells. Finally, recent studies have shown that natural toxins can be conjugated to drugs that bind to overexpressed receptors in cancer cells, generating targeted-toxins to selectively kill cancer cells. These targeted-toxins are highly effective against radiation- and chemotherapy-resistant cancer cells, making them good candidates for clinical trials in GBM patients. In this review, we discuss recent studies that reveal new possibilities of GBM treatment taking into account cancer stem cells, angiogenesis, microglial cells and drug delivery in the development of new targeted-therapies.

Towards tailored therapy of glioblastoma multiforme

Gliobastoma multiform (GBM) is the most common and aggressive brain tumor, which is characterized by its infiltrative nature. Current standard therapy for GBMs consists of surgery followed by radiotherapy combined with the alkylating agent temozolomide (TMZ). Recent clinical trials have demonstrated that this chemo-irradiation approach results in a significant increase in survival compared to radiotherapy alone. Nevertheless, due to tumor recurrence, the median survival time is still limited to approximately 15 months. Recently, several studies have focused on aberrant signal transduction in GBM, resistance mechanisms of GBM to TMZ and to radiotherapy. Attention has been focused on molecular targets including phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, protein kinase C (pKC) pathway, Ras/mitogen-activated protein kinase pathway (MAPK), Wnt pathway and intrinsic or extrinsic apoptosis pathways. In addition, research has been directed to radiotherapy and radiosensitizing agents, and cancer gene therapy as well. This article will address several resistance mechanisms of GBM to chemotherapy and radiotherapy and the recent preclinical and clinical studies on targeted therapy.

Cell surface receptors in malignant glioma

Despite advances in surgery, radiation, and chemotherapy, malignant gliomas are still highly lethal tumors. Traditional treatments that rely on nonspecific, cytotoxic approaches have a marginal impact on patient survival. However, recent advances in the molecular cancer biology underlying glioma pathogenesis have revealed that abnormalities in common cell surface receptors, including receptor tyrosine kinase and other cytokines, mediate the abnormal cellular signal pathways and aggressive biological behavior among the majority of these tumors. Some cell surface receptors have been targeted by novel agents in preclinical and clinical development. Such cancer-specific targeted agents might offer the promise of improved cancer control without substantial toxicity. Here, we review these common cell surface receptors with clinical significance for malignant glioma and discuss the molecular characteristics, pathological significance, and potential therapeutic application of these cell surface receptors. We also summarize the clinical trials of drugs targeting these cell surface receptors in malignant glioma patients.

Advances in the design and synthesis of prazosin derivatives over the last ten years

INTRODUCTION

Mechanistic, translational and pharmacological studies led to the identification and discovery of the preferred localization, binding characteristics, structure and functional properties of α1-adrenoceptor (α1-AR) subtypes in the bladder neck, bladder and prostate gland. The evidence gathered on α1-ARs, provided a molecular platform for the development of subtype-selective antagonists, resulting in more effective approaches targeting those receptors for the treatment of outlet bladder obstruction and benign prostate hyperplasia.

AREAS COVERED

Advances over the last decade in the design and optimization of Prazosin, Doxazosin and Terazosin quinazoline-based derivatives as α1-AR antagonists. Evidence on the metabolic and growth interference action by these agents, in addition to their smooth-muscle-relaxing effects. The new action recognition emerges from data on the inhibitory effect of quinazoline-based antagonists on primary tumor growth and progression to metastasis. In addition to the cellular findings in the prostate, functional validation and therapeutic effects of selected lead pharmaceutically optimized derivatives in the context of impairing vascularity and triggering tumor apoptosis.

EXPERT OPINION

Knowledge on targeting intracellular signalling pathways driving the cellular response via an α1-AR-dependent and independent antagonistic action, must be invested towards the optimization of new agents that while bypassing AR, exhibit improved pharmacological efficacy against human cancer.

Determination of cediranib in mouse plasma and brain tissue using high-performance liquid chromatography-mass spectrometry

A new high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) assay for cediranib, a tyrosine kinase inhibitor for VEGFRs, was developed and validated, for the determination of plasma and brain levels of cediranib in small specimen volumes. Tyrphostin (AG1478) was used as internal standard. Mouse plasma and brain homogenate samples were prepared using liquid-liquid extraction. The assay was validated for a 2.5-2500 ng/mL concentration range for plasma, and for 1-2000 ng/mL range for brain homogenate. For these calibration ranges, within-assay variabilities were 1.1-14.3% for plasma and 1.5-9.4% for brain homogenate; between-assay variabilities were 2.4-9.2% for plasma, and 4.9-10.2% for brain homogenate. Overall accuracy ranged from 101.5 to 107.0% for plasma and 96.5 to 100.2% for brain homogenate, for all target concentrations. The developed assay has been successfully applied for a brain distribution study in mice at an oral dose of 5 mg/kg.

Glioblastoma. Part II: Future directions

Although uncommon, "brain cancer" is one of the most feared diseases that afflict human beings. While still regarded as one of the most deadly forms of primary malignant brain neoplasm, recent advances in the treatment of Glioblastoma Multiforme (GBM) have offered new hope for patients, families and clinicians. In the first part of this two-part evidence-based review, we focused on the multidisciplinary advances that have established the current standard of care practice in the management of GBM. The second part discusses ongoing research efforts, both ongoing clinical trial efforts as well as some of the newer technologies that are forming the promise of the future.

Novel angiogenesis inhibitors: addressing the issue of redundancy in the angiogenic signaling pathway

Angiogenesis, the formation of new blood vessels from established vasculature, is a fundamental process in the growth and metastasis of solid tumours. It is a complex, tightly regulated process that requires the coordinated action of antiangiogenic and proangiogenic factors, the balance of which becomes disturbed during tumour development. Vascular endothelial growth factor (VEGF) and its receptor are the key mediators of angiogenesis and targets for multiple pharmacologic agents. Many patients treated with VEGF inhibitors survive for a longer period; however, eventual resistance is associated with progressive disease and death. Multiple approaches to overcome resistance have been investigated with varying success, including the use of agents that target multiple angiogenic factors or co-administration of angiogenesis inhibitors with standard chemotherapy or radiotherapy. It would appear that the future of angiogenic inhibitors lies in the intelligent combination of multiple targeted agents with other angiogenic inhibitors, as well as more conventional therapies to maximise therapeutic effect.

Current and emerging molecular targets in glioma

Gliomas are the most common and lethal neurological cancers. Despite research efforts, the prognosis for patients with malignant gliomas remains poor. Advances in the understanding of cellular and molecular alterations in gliomas have led to the emergence of experimental molecularly targeted therapies. This article summarizes recent progress in the development of targeted therapies for glioma, focusing on emerging molecular targets, including neuropeptide and neurotrophin pathways, glutamate receptors, epigenetic mechanisms and glioma stem cell targets. Recent clinical trials of small molecules and antibodies targeted at growth factor pathways and intracellular signaling cascades are also discussed.

Experimental approaches for the treatment of malignant gliomas

Malignant gliomas, which include glioblastomas and anaplastic astrocytomas, are the most common primary tumors of the brain. Over the past 30 years, the standard treatment for these tumors has evolved to include maximal safe surgical resection, radiation therapy and temozolomide chemotherapy. While the median survival of patients with glioblastomas has improved from 6 months to 14.6 months, these tumors continue to be lethal for the vast majority of patients. There has, however, been recent substantial progress in our mechanistic understanding of tumor development and growth. The translation of these genetic, epigenetic and biochemical findings into therapies that have been tested in clinical trials is the subject of this review.

Differentiating and apoptotic dose-dependent effects in (-)-alpha-bisabolol-treated human endothelial cells

The effect on angiogenesis of (-)-alpha-bisabolol [(-)-6-methyl-2-(4-methyl-3-cyclohexen-1-yl)-5-hepten-2-ol] (1), a widely distributed plant sesquiterpene alcohol, was investigated for the first time. Human endothelial cells treated with 1 were analyzed for their ability to differentiate and organize in microvessels and for their sensitivity to this compound in terms of cytotoxicity and cell growth inhibition. Within 24 h of the treatment with 5 microM 1, cells underwent massive death. Apoptosis induction was responsible for cytotoxicity triggered by 1 as revealed by the release of cytochrome c from the mitochondria, reduction of the Bcl-2/Bax ratio, and caspase 3 activation. At a lower, non-apoptotic concentration (0.25 microM), 1 showed a differentiating effect resulting in growth inhibition, invasiveness reduction, and tubule stabilization.

Rapid development of hypertension and proteinuria with cediranib, an oral vascular endothelial growth factor receptor inhibitor

BACKGROUND AND OBJECTIVES

Hypertension and proteinuria are common but poorly understood renal toxicities of vascular endothelial growth factor (VEGF) receptor signaling pathway inhibitors. In this phase II study of cediranib (AZD2171) for recurrent epithelial ovarian cancer, the time course and severity of BP changes and proteinuria were characterized.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

46 women ages 41 to 77 years were treated with cediranib. 26% had baseline hypertension. Twice-daily BP was recorded. Urinalyses were performed every 2 weeks, and in some patients proteinuria was further quantified.

RESULTS

31 women (67%) developed hypertension by day 3; 87% by the end of the study. 43% developed grade > or =3 hypertension. Mean systolic BP increase over 3 days was 18 mmHg. Women above the mean age (> or =57 years) had a larger rise in systolic BP by day 3 (15.9 versus 7.0 mmHg). 14 women developed proteinuria. There was a dose response (45 versus 30 mg daily). Proteinuria also developed rapidly, with 7 of 14 women developing proteinuria within 2 weeks. Only 7 of 20 women who developed grade 3 hypertension developed proteinuria.

CONCLUSIONS

Cediranib induced a rapid but variable rise in BP within 3 days of initiation in most patients. Proteinuria was common and also developed rapidly. The rapid development of hypertension suggests that acute inhibition of VEGF-dependent vasodilation might explain the BP rise with VEGF inhibitors. Clinicians must be vigilant in early detection and management of toxicities of this expanding drug class, especially in older patients.