Cilengitide with metronomic temozolomide, procarbazine, and standard radiotherapy in patients with glioblastoma and unmethylated MGMT gene promoter in ExCentric, an open-label phase II trial

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Progress in Glioma Stem Cell Research

Glioblastoma multiforme (GBM) represents a diverse spectrum of primary tumors notorious for their resistance to established therapeutic modalities. Despite aggressive interventions like surgery, radiation, and chemotherapy, these tumors, due to factors such as the blood-brain barrier, tumor heterogeneity, glioma stem cells (GSCs), drug efflux pumps, and DNA damage repair mechanisms, persist beyond complete isolation, resulting in dismal outcomes for glioma patients. Presently, the standard initial approach comprises surgical excision followed by concurrent chemotherapy, where temozolomide (TMZ) serves as the foremost option in managing GBM patients. Subsequent adjuvant chemotherapy follows this regimen. Emerging therapeutic approaches encompass immunotherapy, including checkpoint inhibitors, and targeted treatments, such as bevacizumab, aiming to exploit vulnerabilities within GBM cells. Nevertheless, there exists a pressing imperative to devise innovative strategies for both diagnosing and treating GBM. This review emphasizes the current knowledge of GSC biology, molecular mechanisms, and associations with various signals and/or pathways, such as the epidermal growth factor receptor, PI3K/AKT/mTOR, HGFR/c-MET, NF-κB, Wnt, Notch, and STAT3 pathways. Metabolic reprogramming in GSCs has also been reported with the prominent activation of the glycolytic pathway, comprising aldehyde dehydrogenase family genes. We also discuss potential therapeutic approaches to GSC targets and currently used inhibitors, as well as their mode of action on GSC targets.

Leptomeningeal neuraxis relapse in glioblastoma is an uncommon but not rare event associated with poor outcome

BACKGROUND

Spinal neuraxis leptomeningeal metastasis (LM) relapse in glioblastoma is an uncommon event that is challenging to manage. This study aims to determine the incidence, associated factors, and outcome of LM relapse in patients with glioblastoma managed with radical intent.

METHODS

Patients managed for glioblastoma using the EORTC-NCIC (Stupp) Protocol from 2007 to 2019 were entered into a prospective ethics-approved database. Follow-up included routine cranial MRI surveillance with further imaging as clinically indicated. LM relapse was determined by MRI findings and/or cerebrospinal fluid analysis. The chi-square test of independence was used to evaluate clinico-pathologic factors associated with increased risk of subsequent LM relapse. Median survival post-LM relapse was calculated using Kaplan-Meier technique.

RESULTS

Four-hundred-and-seven patients were eligible, with median follow-up of 60 months for surviving patients. Eleven (2.7%) had LM at first relapse and in total 21 (5.1%) experienced LM in the entire follow-up period. Sites of LM relapse were 8 (38%) focal spinal, 2 (10%) focal brainstem medulla and 11 (52%) diffuse spinal. Median overall survival from initial diagnosis for the entire cohort was 17.6 months (95% CI 16.7-19.0). Median survival from LM relapse to death was 39 days (95% CI: 19-107). Factors associated with LM relapse were age less than 50 years (p < 0.01), initial disease located in the temporal lobe (p < 0.01) and tumours lacking MGMT promoter methylation (p < 0.01).

CONCLUSIONS

LM relapse is an uncommon but not rare event in patients managed radically for glioblastoma. It is associated with poor outcome with the majority of patients deceased within two months of recognition.

Advances in Treatment of Isocitrate Dehydrogenase (IDH)-Wildtype Glioblastomas

PURPOSE OF REVIEW

The management of isocitrate dehydrogenase (IDH)-wildtype glioblastomas is an area of unmet need. Despite multimodal therapy incorporating maximal safe resection, radiotherapy, and temozolomide, clinical outcomes remain poor. At disease progression or relapse, available systemic agents such as temozolomide, lomustine, and bevacizumab have limited efficacy. We review the recent advances in the treatment of IDH-wildtype glioblastomas.

RECENT FINDINGS

A broad repertoire of systemic agents is in the early stages of development, encompassing the areas of precision medicine, immunotherapy, and repurposed medications. The use of medical devices may present opportunities to bypass the blood-brain barrier. Novel clinical trial designs aim to efficiently test treatment options to advance the field. There are a number of emerging treatment options for IDH-wildtype glioblastomas which are undergoing evaluation in clinical trials. Advances in our scientific understanding of IDH-wildtype glioblastomas offer hope and the prospect of incremental improvements in clinical outcomes.

Peptide modulators of cell migration: Overview, applications and future development

Cell migration is a key physiological process in the development and homeostasis of multicellular organisms; errors in this complex system can trigger the development of cancer or inflammatory disorders. Therefore, modulating cell migration provides opportunities for drug discovery. Peptides are gaining importance on the global therapeutics market, given their unique properties compared with established small-molecule drugs or biologics. In this review, we identified over 470 peptides modulating cell migration and analyzed their characteristics. Over 95% of these peptides are in the discovery or preclinical stage, because the transition of peptide hits into drug leads often results in a bottleneck in the development process. We summarize chemical strategies in (pre-)clinical development to enhance drug-like properties of bioactive peptides.

TGF-beta signal transduction: biology, function and therapy for diseases

The transforming growth factor beta (TGF-β) is a crucial cytokine that get increasing concern in recent years to treat human diseases. This signal controls multiple cellular responses during embryonic development and tissue homeostasis through canonical and/or noncanonical signaling pathways. Dysregulated TGF-β signal plays an essential role in contributing to fibrosis via promoting the extracellular matrix deposition, and tumor progression via inducing the epithelial-to-mesenchymal transition, immunosuppression, and neovascularization at the advanced stage of cancer. Besides, the dysregulation of TGF-beta signal also involves in other human diseases including anemia, inflammatory disease, wound healing and cardiovascular disease et al. Therefore, this signal is proposed to be a promising therapeutic target in these diseases. Recently, multiple strategies targeting TGF-β signals including neutralizing antibodies, ligand traps, small-molecule receptor kinase inhibitors targeting ligand-receptor signaling pathways, antisense oligonucleotides to disrupt the production of TGF-β at the transcriptional level, and vaccine are under evaluation of safety and efficacy for the forementioned diseases in clinical trials. Here, in this review, we firstly summarized the biology and function of TGF-β in physiological and pathological conditions, elaborated TGF-β associated signal transduction. And then, we analyzed the current advances in preclinical studies and clinical strategies targeting TGF-β signal transduction to treat diseases.

A molecular interactome of the glioblastoma perivascular niche reveals integrin binding sialoprotein as a mediator of tumor cell migration

Glioblastoma (GBM) is characterized by extensive microvascular hyperproliferation. In addition to supplying blood to the tumor, GBM vessels also provide trophic support to glioma cells and serve as conduits for migration into the surrounding brain, promoting recurrence. Here, we enrich CD31-expressing glioma vascular cells (GVCs) and A2B5-expressing glioma tumor cells (GTCs) from primary GBM and use RNA sequencing to create a comprehensive molecular interaction map of the secreted and extracellular factors elaborated by GVCs that can interact with receptors and membrane molecules on GTCs. To validate our findings, we utilize functional assays, including a hydrogel-based migration assay and in vivo mouse models to demonstrate that one identified factor, the little-studied integrin binding sialoprotein (IBSP), enhances tumor growth and promotes the migration of GTCs along the vasculature. This perivascular niche interactome will serve as a resource to the research community in defining the potential functions of the GBM vasculature.

Comparative analysis of cancer cell responses to targeted radionuclide therapy (TRT) and external beam radiotherapy (EBRT)

The vast majority of our knowledge regarding cancer radiobiology and the activation of radioresistance mechanisms emerged from studies using external beam radiation therapy (EBRT). Yet, less is known about the cancer response to internal targeted radionuclide therapy (TRT). Our comparative phosphoproteomics analyzed cellular responses to TRT with lutetium-177-labeled minigastrin analogue [¹⁷⁷Lu]Lu-PP-F11N (β-emitter) and EBRT (ɣ-rays) in CCKBR-positive cancer cells. Activation of DNA damage response by p53 was induced by both types of radiotherapy, whereas TRT robustly increased activation of signaling pathways including epidermal growth factor receptor (EGFR), mitogen-activated protein kinases (MAPKs) or integrin receptor. Inhibition of EGFR or integrin signaling sensitized cancer cells to radiolabeled minigastrin. In vivo, EGFR inhibitor erlotinib increased therapeutic response to [¹⁷⁷Lu]Lu-PP-F11N and median survival of A431/CCKBR-tumor bearing nude mice. In summary, our study explores a complex scenario of cancer responses to different types of irradiation and pinpoints the radiosensitizing strategy, based on the targeting survival pathways, which are activated by TRT.

Glioma targeted therapy: insight into future of molecular approaches

Gliomas are the common type of brain tumors originating from glial cells. Epidemiologically, gliomas occur among all ages, more often seen in adults, which males are more susceptible than females. According to the fifth edition of the WHO Classification of Tumors of the Central Nervous System (WHO CNS5), standard of care and prognosis of gliomas can be dramatically different. Generally, circumscribed gliomas are usually benign and recommended to early complete resection, with chemotherapy if necessary. Diffuse gliomas and other high-grade gliomas according to their molecule subtype are slightly intractable, with necessity of chemotherapy. However, for glioblastoma, feasible resection followed by radiotherapy plus temozolomide chemotherapy define the current standard of care. Here, we discuss novel feasible or potential targets for treatment of gliomas, especially IDH-wild type glioblastoma. Classic targets such as the p53 and retinoblastoma (RB) pathway and epidermal growth factor receptor (EGFR) gene alteration have met failure due to complex regulatory network. There is ever-increasing interest in immunotherapy (immune checkpoint molecule, tumor associated macrophage, dendritic cell vaccine, CAR-T), tumor microenvironment, and combination of several efficacious methods. With many targeted therapy options emerging, biomarkers guiding the prescription of a particular targeted therapy are also attractive. More pre-clinical and clinical trials are urgently needed to explore and evaluate the feasibility of targeted therapy with the corresponding biomarkers for effective personalized treatment options.

Clinical strategies to manage adult glioblastoma patients without MGMT hypermethylation

Glioblastoma (GBM) is a highly malignant brain tumor with a dismal prognosis. Standard therapy for GBM comprises surgical resection, followed by radiotherapy plus concomitant and adjuvant temozolomide (TMZ) therapy. The methylation status of the O6-methylguanine DNA methyltransferase (MGMT) promoter is one of the most essential predictive biomarkers for patients with GBM treated with TMZ. Patients with an unmethylated MGMT promoter (umMGMT), who comprise 60% of patients with GBM, present an even worse prognosis because of TMZ resistance. Radiotherapy with various fractionation, chemotherapy compensating for TMZ, targeted therapy against diverse oncogenic pathways, immunotherapy of vaccine or immune checkpoint inhibitor, and tumor treating fields have been studied in umMGMT GBM patients. However, most efforts have yielded negative results or merely minimal improvements. Therefore, effective patient subgroup selection concerning precision medicine has become the focus. By assigning different treatments to the corresponding patient subgroups, a better curative effect and subsequently prolonged survival can be achieved. In this review, we re-evaluate the value of standard TMZ therapy and summarize the new clinical strategies and attempts to treat patients with umMGMT, which yielded positive and negative results, to provide alternative treatment options and discuss future directions of umMGMT GBM treatment.

The immune landscape of common CNS malignancies: implications for immunotherapy

Immunotherapy has enabled remarkable therapeutic responses across cancers of various lineages, albeit with some notable exceptions such as glioblastoma. Several previous misconceptions, which have impaired progress in the past, including the presence and role of the blood-brain barrier and a lack of lymphatic drainage, have been refuted. Nonetheless, a subset of patients with brain metastases but, paradoxically, not the vast majority of those with gliomas are able to respond to immune-checkpoint inhibitors. Immune profiling of samples obtained from patients with central nervous system malignancies using techniques such as mass cytometry and single-cell sequencing along with experimental data from genetically engineered mouse models have revealed fundamental differences in immune composition and immunobiology that not only explain the differences in responsiveness to these agents but also lay the foundations for immunotherapeutic strategies that are applicable to gliomas. Herein, we review the emerging data on the differences in immune cell composition, function and interactions within central nervous system tumours and provide guidance on the development of novel immunotherapies for these historically difficult-to-treat cancers.

High-dose radiotherapy in newly diagnosed low-grade gliomas with nonmethylated O(6)-methylguanine-DNA methyltransferase

Background

Patients with low-grade gliomas (LGGs) harboring O⁶-methylguanine-DNA methyltransferase promoter nonmethylation (MGMT-non-pM) have a particularly short survival and are great resistance to chemotherapy. The objective of this study was to assess the efficacy of high-dose radiotherapy (RT) for LGGs with MGMT-non-pM.

Methods

268 patients with newly diagnosed adult supratentorial LGGs from the multicenter Chinese Glioma Cooperative Group (CGCG) received postoperative RT during 2005–2018. MGMT promoter methylation analysis was conducted by pyrosequencing in all patients. Univariate and multivariate analysis were performed using the Cox regression to determine the prognostic factors for overall survival (OS) and progression-free survival (PFS). RT dose–response on MGMT status defined subtypes was analyzed.

Results

On univariate analysis, the following were statistically significant favorable factors for both PFS and OS: oligodendrogliomas(p = 0.002 and p = 0.005), high-dose RT (> 54 Gy) (p = 0.021 and p = 0.029) and 1p/19q codeletion (p < 0.001 and p = 0.001). On multivariate analysis, RT dose (> 54 Gy vs. ≤ 54 Gy) and IDH mutation were independently prognostic markers for OS (HR, 0.47; 95%CI, 0.22–0.98; p = 0.045; and HR, 0.44; 95%CI, 0.21–0.96; p = 0.038, respectively) and PFS (HR, 0.48; 95%CI, 0.26–0.90; p = 0.022; and HR, 0.51; 95%CI, 0.26–0.98; p = 0.044, respectively). High-dose RT was associated with longer OS (HR, 0.56; 95%CI, 0.32–0.96; p = 0.036) and PFS (HR, 0.58; 95%CI, 0.35–0.96; p = 0.033) than low-dose RT in MGMT-non-pM subtype. In contrast, no significant difference in either OS (p = 0.240) or PFS (p = 0.395) was observed with high-dose RT in the MGMT-pM subtype.

Conclusions

High-dose RT (> 54 Gy) is an independently protective factor for LGGs and is associated with improved survival in patients with MGMT-non-pM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01878-3.

Comprehensive understanding of anchorage-independent survival and its implication in cancer metastasis

Detachment is the initial and critical step for cancer metastasis. Only the cells that survive from detachment can develop metastases. Following the disruption of cell-extracellular matrix (ECM) interactions, cells are exposed to a totally different chemical and mechanical environment. During which, cells inevitably suffer from multiple stresses, including loss of growth stimuli from ECM, altered mechanical force, cytoskeletal reorganization, reduced nutrient uptake, and increased reactive oxygen species generation. Here we review the impact of these stresses on the anchorage-independent survival and the underlying molecular signaling pathways. Furthermore, its implications in cancer metastasis and treatment are also discussed.

Cyr61 from adipose-derived stem cells promotes colorectal cancer metastasis and vasculogenic mimicry formation via integrin αV β5

Adipose‐derived stem cells (ADSCs) play a vital role in colorectal cancer (CRC) progression, but the mechanism remains largely unknown. Herein, we found that ADSCs isolated from CRC patients produced more cysteine‐rich 61 (Cyr61) than those from healthy donors, and the elevated serum Cyr61 levels were associated with advanced TNM stages. Moreover, serum Cyr61 displayed a better diagnostic value for CRC compared to carcinoembryonic antigen (CEA) and carbohydrate antigen (CA19‐9). Mechanistically, integrin α_Vβ₅ was identified as the functional receptor by which Cyr61 promotes CRC cell metastasis in vitro and in vivo by activating the α_Vβ₅/FAK/NF‐κB signaling pathway. In addition, Cyr61 promotes vasculogenic mimicry (VM) formation, thereby promoting tumor growth and metastasis through a α_Vβ₅/FAK/HIF‐1α/STAT3/MMP2 signaling cascade. Histologically, xenografts and clinical samples of CRC both exhibited VM, which was correlated with HIF‐1α and MMP2 activation. Notably, we demonstrated the synergistic effect of combined anti‐VM therapy (integrin α_Vβ₅ inhibitor) and anti‐VEGF therapy (bevacizumab) in patient‐derived xenograft models. Further investigation showed that CRC cell‐derived exosomal STAT3 promoted Cyr61 transcription in ADSCs. These findings indicate that Cyr61 derived from ADSCs plays a critical role in promoting CRC progression via integrin α_Vβ₅ and provides a novel antitumor strategy by targeting Cyr61/α_Vβ₅.

Brain-invasive meningiomas: molecular mechanisms and potential therapeutic options

Meningiomas are the most commonly diagnosed benign intracranial adult tumors. Subsets of meningiomas that present with extensive invasion into surrounding brain areas have high recurrence rates, resulting in difficulties for complete resection, substantially increased mortality of patients, and are therapeutically challenging for neurosurgeons. Exciting new data have provided insights into the understanding of the molecular machinery of invasion. Moreover, clinical trials for several novel approaches have been launched. Here, we will highlight the mechanisms which govern brain invasion and new promising therapeutic approaches for brain-invasive meningiomas, including pharmacological approaches targeting three major aspects of tumor cell invasion: extracellular matrix degradation, cell adhesion, and growth factors, as well as other innovative treatments such as immunotherapy, hormone therapy, Tumor Treating Fields, and biodegradable copolymers (wafers), impregnated chemotherapy. Those ongoing studies can offer more diversified possibilities of potential treatments for brain-invasive meningiomas, and help to increase the survival benefits for patients.

Extracellular Matrix Proteins Confer Cell Adhesion-Mediated Drug Resistance Through Integrin α v in Glioblastoma Cells

Chemotherapy resistance to glioblastoma (GBM) remains an obstacle that is difficult to overcome, leading to poor prognosis of GBM patients. Many previous studies have focused on resistance mechanisms intrinsic to cancer cells; the microenvironment surrounding tumor cells has been found more recently to have significant impacts on the response to chemotherapeutic agents. Extracellular matrix (ECM) proteins may confer cell adhesion-mediated drug resistance (CAMDR). Here, expression of the ECM proteins laminin, vitronectin, and fibronectin was assessed in clinical GBM tumors using immunohistochemistry. Then, patient-derived GBM cells grown in monolayers on precoated laminin, vitronectin, or fibronectin substrates were treated with cilengitide, an integrin inhibitor, and/or carmustine, an alkylating chemotherapy. Cell adhesion and viability were quantified. Transcription factor (TF) activities were assessed over time using a bioluminescent assay in which GBM cells were transduced with lentiviruses containing consensus binding sites for specific TFs linked to expression a firefly luciferase reporter. Apoptosis, mediated by p53, was analyzed by Western blotting and immunocytofluorescence. Integrin α_v activation of the FAK/paxillin/AKT signaling pathway and effects on expression of the proliferative marker Ki67 were investigated. To assess effects of integrin α_v activation of AKT and ERK pathways, which are typically deregulated in GBM, and expression of epidermal growth factor receptor (EGFR), which is amplified and/or mutated in many GBM tumors, shRNA knockdown was used. Laminin, vitronectin, and fibronectin were abundant in clinical GBM tumors and promoted CAMDR in GBM cells cultured on precoated substrates. Cilengitide treatment induced cell detachment, which was most pronounced for cells cultured on vitronectin. Cilengitide treatment increased cytotoxicity of carmustine, reversing CAMDR. ECM adhesion increased activity of NFκB and decreased that of p53, leading to suppression of p53-mediated apoptosis and upregulation of multidrug resistance gene 1 (MDR1; also known as ABCB1 or P-glycoprotein). Expression of Ki67 was correlative with activation of the integrin α_v-mediated FAK/paxillin/AKT signaling pathway. EGFR expression increased with integrin α_v knockdown GBM cells and may represent a compensatory survival mechanism. These results indicate that ECM proteins confer CAMDR through integrin α_v in GBM cells.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of emerging developments in the management of newly diagnosed glioblastoma

TARGET POPULATION

These recommendations apply to adult patients with newly diagnosed or suspected glioblastoma.

IMAGING

Question What imaging modalities are in development that may be able to provide improvements in diagnosis, and therapeutic guidance for individuals with newly diagnosed glioblastoma?

RECOMMENDATION

Level III: It is suggested that techniques utilizing magnetic resonance imaging for diffusion weighted imaging, and to measure cerebral blood and magnetic spectroscopic resonance imaging of N-acetyl aspartate, choline and the choline to N-acetyl aspartate index to assist in diagnosis and treatment planning in patients with newly diagnosed or suspected glioblastoma.

SURGERY

Question What new surgical techniques can be used to provide improved tumor definition and resectability to yield better tumor control and prognosis for individuals with newly diagnosed glioblastoma?

RECOMMENDATIONS

Level II: The use of 5-aminolevulinic acid is recommended to improve extent of tumor resection in patients with newly diagnosed glioblastoma. Level II: The use of 5-aminolevulinic acid is recommended to improve median survival and 2 year survival in newly diagnosed glioblastoma patients with clinical characteristics suggesting poor prognosis. Level III: It is suggested that, when available, patients be enrolled in properly designed clinical trials assessing the value of diffusion tensor imaging in improving the safety of patients with newly diagnosed glioblastoma undergoing surgery.

NEUROPATHOLOGY

Question What new pathology techniques and measurement of biomarkers in tumor tissue can be used to provide improved diagnostic ability, and determination of therapeutic responsiveness and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level II: Assessment of tumor MGMT promoter methylation status is recommended as a significant predictor of a longer progression free survival and overall survival in patients with newly diagnosed with glioblastoma. Level II: Measurement of tumor expression of neuron-glia-2, neurofilament protein, glutamine synthetase and phosphorylated STAT3 is recommended as a predictor of overall survival in patients with newly diagnosed with glioblastoma. Level III: Assessment of tumor IDH1 mutation status is suggested as a predictor of longer progression free survival and overall survival in patients with newly diagnosed with glioblastoma. Level III: Evaluation of tumor expression of Phosphorylated Mitogen-Activated Protein Kinase protein, EGFR protein, and Insulin-like Growth Factor-Binding Protein-3 is suggested as a predictor of overall survival in patients with newly diagnosed with glioblastoma.

RADIATION

Question What radiation therapy techniques are in development that may be used to provide improved tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level III: It is suggested that patients with newly diagnosed glioblastoma undergo pretreatment radio-labeled amino acid tracer positron emission tomography to assess areas at risk for tumor recurrence to assist in radiation treatment planning. Level III: It is suggested that, when available, patients be with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of radiation dose escalation, altered fractionation, or new radiation delivery techniques.

CHEMOTHERAPY

Question What emerging chemotherapeutic agents or techniques are available to provide better tumor control and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no emerging chemotherapeutic agents or techniques were identified in this review that improved tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of chemotherapy.

MOLECULAR AND TARGETED THERAPY

Question What new targeted therapy agents are available to provide better tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no new molecular and targeted therapies have clearly provided better tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of molecular and targeted therapies IMMUNOTHERAPY: Question What emerging immunotherapeutic agents or techniques are available to provide better tumor control and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no immunotherapeutic agents have clearly provided better tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of immunologically-based therapies.

NOVEL THERAPIES

Question What novel therapies or techniques are in development to provide better tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level II: The use of tumor-treating fields is recommended for patients with newly diagnosed glioblastoma who have undergone surgical debulking and completed concurrent chemoradiation without progression of disease at the time of tumor-treating field therapy initiation. Level II: It is suggested that, when available, enrollment in properly designed studies of vector containing herpes simplex thymidine kinase gene and prodrug therapies be considered in patients with newly diagnosed glioblastoma.

Recent clinical evidence on metronomic dosing in controlled clinical trials: a systematic literature review

Introduction: Metronomic dosing is used to give continuous chemotherapy at low doses. The low doses have minimal side effects and may enable cancer treatment to be remodeled toward the management of chronic disease.Methods: We searched PubMed database to obtain relevant clinical trials studying metronomic chemotherapy (MCT). Our main focus was to find controlled phase II and phase III trials.Results: This systematic review summarizes the results of 91 clinical reports focusing on randomized phase II and phase III clinical studies between 2012 and 2018. During that time, nine randomized phase II and 10 randomized phase III studies were published. In the majority of the studies, MCT was well tolerated, and major side effects were rarely seen. Altogether, 4 phase III studies and 4 randomized phase II studies presented positive results and some clinical benefit.Discussion: Most of the studies did not show significantly improved overall survival or progression-free survival. Typically, the metronomic dosing was explored in a maintenance setup and was added to other agents given within normal high doses, whereas no trial was performed challenging metronomic dosing and best supportive care in later treatment lines. Therefore, there is no definite evidence on the efficacy of single metronomic dosing and firm evidence of metronomic dosing is still missing. There is a need for further confirmation of the usefulness of this approach in clinical practice.

Anti-epidermal growth factor receptor therapy for glioblastoma in adults

BACKGROUND

Glioblastoma is an uncommon but highly aggressive type of brain tumour. Significant gains have been achieved in the molecular understanding and the pathogenesis of glioblastomas, however clinical improvements are difficult to obtain for many reasons. The current standard of care involves maximal safe surgical resection followed by chemoradiation and then adjuvant chemotherapy European Organisation for Research and Treatment of Cancer and the NCIC Clinical Trials Group (EORTC-NCIC) protocol with a median survival of 14.6 months. Successive phase III international randomised controlled studies have failed to significantly demonstrate survival advantage with newer drugs. Epidermal growth factor receptor (EGFR) is observed to be aberrant in 30% to 60% of glioblastomas. The receptor aberrancy is driven by abnormal gene amplification, receptor mutation, or both, in particular the extracellular vIII domain. EGFR abnormalities are common in solid tumours, and the advent of anti-EGFR therapies in non-small cell lung cancer and colorectal adenocarcinomas have greatly improved clinical outcomes. Anti-EGFR therapies have been investigated amongst glioblastomas, however questions remain about its ongoing role in glioblastoma management. This review aimed to report on the available evidence to date and perform a systematic analysis on the risks and benefits of use of anti-EGFR therapies in glioblastomas.

OBJECTIVES

To evaluate the efficacy and harms of anti-EGFR therapies for glioblastoma in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, EBM Reviews databases, with supplementary handsearches to identify all available and relevant studies to 20 April 2020.

SELECTION CRITERIA

All randomised controlled trials (RCTs) using anti-EGFR therapies in adults with glioblastoma were eligible for inclusion. Anti-EGFR therapies included tyrosine kinase inhibitors, monoclonal antibodies, or vaccines. The comparison included investigational product added to standard of care versus standard of care or placebo, or investigational product against standard of care or placebo.

DATA COLLECTION AND ANALYSIS

The authorship team screened the search results and recorded the extracted data for analysis. We used standard Cochrane methodology to performed quantitative meta-analysis if two or more studies had appropriate and available data. Otherwise, we conducted a qualitative and descriptive analysis. We used the GRADE system to rate the certainty of the evidence. The analysis was performed along the two clinical settings: first-line (after surgery) and recurrent disease (after failure of first line treatment). Where information was available, we documented overall survival, progression-free survival, adverse events, and quality of life data from eligible studies.

MAIN RESULTS

The combined searches initially identified 912 records (after removal of duplicates), and further screening resulted in 19 records for full consideration. We identified nine eligible studies for inclusion in the review. There were three first-line studies and six recurrent studies. Five studies used tyrosine kinase inhibitors (TKIs); two studies used monoclonal antibodies; and two studies used targeted vaccines. More recent studies presented greater detail in the conduct of their studies and thus had a lower risk of bias. We observed no evidence benefit in overall survival with the use of anti-EGFR therapy in the first-line or recurrent setting (hazard ratio (HR) 0.89, 95% confidence interval (CI) 0.76 to 1.04; 3 RCTs, 1000 participants, moderate-certainty evidence; and HR 0.79, 95% CI 0.51 to 1.21, 4 RCTs, 489 participants, low-certainty evidence, respectively). All the interventions were generally well tolerated with low-certainty evidence for lymphopenia (odds ratio (OR) 0.97, 95% CI 0.19 to 4.81; 4 RCTs, 1146 participants), neutropenia (OR 1.29, 95% CI 0.82 to 2.03; 4 RCTs, 1146 participants), and thrombocytopenia (OR 3.69, 95% CI 0.51 to 26.51; 4 RCTs, 1146 participants). A notable toxicity relates to ABT-414, where significant ocular issues were detected. The addition of anti-EGFR therapy showed no evidence of an increase in progression-free survival (PFS) in the first-line setting (HR 0.94, 95% CI 0.81 to 1.10; 2 RCTs, 894 participants, low-certainty evidence). In the recurrent setting, there was an increase in PFS with the use of anti-EGFR therapy (HR 0.75, 95% CI 0.58 to 0.96, 3 RCTs, 275 participants, low-certainty evidence). The available quality of life assessment data showed that anti-EGFR therapies were neither detrimental or beneficial when compared to standard care (not estimable).

AUTHORS' CONCLUSIONS

In summary, there is no evidence of a demonstrable overall survival benefit with the addition of anti-EGFR therapy in first-line and recurrent glioblastomas. Newer drugs that are specially designed for glioblastoma targets may raise the possibility of success in this population, but data are lacking at present. Future studies should be more selective in pursuing people displaying specific EGFR targets.

The Role of miRNA for the Treatment of MGMT Unmethylated Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common high-grade intracranial tumor in adults. It is characterized by uncontrolled proliferation, diffuse infiltration due to high invasive and migratory capacities, as well as intense resistance to chemo- and radiotherapy. With a five-year survival of less than 3% and an average survival rate of 12 months after diagnosis, GBM has become a focus of current research to urgently develop new therapeutic approaches in order to prolong survival of GBM patients. The methylation status of the promoter region of the O⁶-methylguanine–DNA methyltransferase (MGMT) is nowadays routinely analyzed since a methylated promoter region is beneficial for an effective response to temozolomide-based chemotherapy. Furthermore, several miRNAs were identified regulating MGMT expression, apart from promoter methylation, by degrading MGMT mRNA before protein translation. These miRNAs could be a promising innovative treatment approach to enhance Temozolomide (TMZ) sensitivity in MGMT unmethylated patients and to increase progression-free survival as well as long-term survival. In this review, the relevant miRNAs are systematically reviewed.

The influence of patient sex on clinical approaches to malignant glioma

Gliomas are tumors that originate from the glial tissue, thus involving the central nervous system with varying degrees of malignancy. The most aggressive and frequent form is glioblastoma multiforme, a disease characterized by resistance to therapies, frequent recurrences, and extremely poor median survival time. Data on overall glioma case studies demonstrate clear sex disparities regarding incidence, prognosis, drug toxicity, clinical outcome, and, recently, prediction of therapeutic response. In this study, we analyze data in the literature regarding malignant glioma, mainly glioblastoma multiforme, focusing on epidemiological and clinical evaluations. Less discussed issues, such as the role of viral infections, energy metabolism, and predictive aspects concerning the possible use of dedicated therapeutic approaches for male or female patients, will be reported together with different estimated pathogenetic mechanisms underlying astrocyte transformation and glioma chemosensitivity. In this era, where personalized/precision medicine is the most important driver for targeted cancer therapies, the lines of evidence discussed herein strongly suggest that clinical approaches to malignant glioma should consider the patient's sex. Furthermore, retrospectively revising previous clinical studies considering patient sex as a crucial variable is recommended.

Long-term trends in glioblastoma survival: implications for historical control groups in clinical trials

Background

Historical controls continue to be used in early-phase brain tumor trials. We aim to show that historical changes in survival trends for glioblastoma (GBM) call into question the use of noncontemporary controls.

Methods

We analyzed data from 46 106 primary GBM cases from the SEER database (1998-2016). We performed trend analysis on survival outcomes (2-year survival probability, median survival, and hazard ratios) and patient characteristics (age, sex, resection extent, and treatment type).

Results

In 2005-2016 (ie, the post-Stupp protocol era), fitting a parameter independently to each year, there was a demonstrable increase in median survival (R² = 0.81, P < .001) and 2-year survival probability (R² = 0.55, P = .006) for GBM. Trend analysis of the hazard ratio showed a significant time-dependent downward trend (R² = 0.62, P = .002). When controlling, via multivariable Cox regression modeling, for age, sex, resection extent, and treatment type, there was a persistent downward trend in hazard ratios with increases in calendar time, especially in the most recent data.

Conclusion

Contemporary GBM patients face a different overall hazard profile from their historical counterparts, which is evident in changes in measures of patient survival and parametric hazard modeling. Though there was a plateau in these measures before 2005 (pre-Stupp protocol), there is no evidence of a new plateau in recent years even when controlling for known prognostic factors (age, sex, resection extent, and treatment type), suggesting that it may be insufficient to match contemporary patients and noncontemporary controls on the basis of these factors.

Cell Adhesion Molecules and Their Roles and Regulation in the Immune and Tumor Microenvironment

The immune system and cancer have a complex relationship with the immune system playing a dual role in tumor development. The effector cells of the immune system can recognize and kill malignant cells while immune system-mediated inflammation can also promote tumor growth and regulatory cells suppress the anti-tumor responses. In the center of all anti-tumor responses is the ability of the immune cells to migrate to the tumor site and to interact with each other and with the malignant cells. Cell adhesion molecules including receptors of the immunoglobulin superfamily and integrins are of crucial importance in mediating these processes. Particularly integrins play a vital role in regulating all aspects of immune cell function including immune cell trafficking into tissues, effector cell activation and proliferation and the formation of the immunological synapse between immune cells or between immune cell and the target cell both during homeostasis and during inflammation and cancer. In this review we discuss the molecular mechanisms regulating integrin function and the role of integrins and other cell adhesion molecules in immune responses and in the tumor microenvironment. We also describe how malignant cells can utilize cell adhesion molecules to promote tumor growth and metastases and how these molecules could be targeted in cancer immunotherapy.

Role of Integrins in Resistance to Therapies Targeting Growth Factor Receptors in Cancer

Integrins contribute to cancer progression and aggressiveness by activating intracellular signal transduction pathways and transducing mechanical tension forces. Remarkably, these adhesion receptors share common signaling networks with receptor tyrosine kinases (RTKs) and support their oncogenic activity, thereby promoting cancer cell proliferation, survival and invasion. During the last decade, preclinical studies have revealed that integrins play an important role in resistance to therapies targeting RTKs and their downstream pathways. A remarkable feature of integrins is their wide-ranging interconnection with RTKs, which helps cancer cells to adapt and better survive therapeutic treatments. In this context, we should consider not only the integrins expressed in cancer cells but also those expressed in stromal cells, since these can mechanically increase the rigidity of the tumor microenvironment and confer resistance to treatment. This review presents some of these mechanisms and outlines new treatment options for improving the efficacy of therapies targeting RTK signaling.

A framework for the development of effective anti-metastatic agents

Most cancer-related deaths are a result of metastasis, and thus the importance of this process as a target of therapy cannot be understated. By asking 'how can we effectively treat cancer?', we do not capture the complexity of a disease encompassing >200 different cancer types - many consisting of multiple subtypes - with considerable intratumoural heterogeneity, which can result in variable responses to a specific therapy. Moreover, we have much less information on the pathophysiological characteristics of metastases than is available for the primary tumour. Most disseminated tumour cells that arrive in distant tissues, surrounded by unfamiliar cells and a foreign microenvironment, are likely to die; however, those that survive can generate metastatic tumours with a markedly different biology from that of the primary tumour. To treat metastasis effectively, we must inhibit fundamental metastatic processes and develop specific preclinical and clinical strategies that do not rely on primary tumour responses. To address this crucial issue, Cancer Research UK and Cancer Therapeutics CRC Australia formed a Metastasis Working Group with representatives from not-for-profit, academic, government, industry and regulatory bodies in order to develop recommendations on how to tackle the challenges associated with treating (micro)metastatic disease. Herein, we describe the challenges identified as well as the proposed approaches for discovering and developing anticancer agents designed specifically to prevent or delay the metastatic outgrowth of cancer.

Optimising Outcomes for Glioblastoma through Subspecialisation in a Regional Cancer Centre

Delivery of highly sophisticated, and subspecialised, management protocols for glioblastoma in low volume rural and regional areas creates potential issues for equivalent quality of care. This study aims to demonstrate the impact on clinical quality indicators through the development of a novel model of care delivering an outsourced subspecialised neuro-oncology service in a regional centre compared with the large volume metropolitan centre. Three hundred and fifty-two patients with glioblastoma were managed under the European Organisation for Research and Treatment of Cancer and National Cancer Institute of Canada Clinical Trials Group (EORTC-NCIC) Protocol, and survival outcome was assessed in relation to potential prognostic factors and the geographical site of treatment, before and after opening of a regional cancer centre. The median overall survival was 17 months (95% CI: 15.5–18.5), with more favourable outcome with age less than 50 years (p < 0.001), near-total resection (p < 0.001), Eastern Cooperative Oncology Group (ECOG) Performance status 0, 1 (p < 0.001), and presence of O-6 methylguanine DNA methyltransferase (MGMT) methylation (p = 0.001). There was no difference in survival outcome for patients managed at the regional centre, compared with metropolitan centre (p = 0.35). Similarly, no difference was seen with clinical quality process indicators of clinical trial involvement, rates of repeat craniotomy, use of bevacizumab and re-irradiation. This model of neuro-oncology subspecialisation allowed equivalent outcomes to be achieved within a regional cancer centre compared to large volume metropolitan centre.

Adaptive adhesion systems mediate glioma cell invasion in complex environments

Diffuse brain invasion by glioma cells prevents effective surgical or molecular-targeted therapy and underlies a detrimental outcome. Migrating glioma cells are guided by complex anatomical brain structures but the exact mechanisms remain poorly defined. To identify adhesion receptor systems and matrix structures supporting glioma cell invasion into brain-like environments we used 2D and 3D organotypic invasion assays in combination with antibody-, peptide- and RNA-based interference. Combined interference with β1 and αV integrins abolished the migration of U-251 and E-98 glioma cells on reconstituted basement membrane; however, invasion into primary brain slices or 3D astrocyte-based scaffolds and migration on astrocyte-deposited matrix was only partly inhibited. Any residual invasion was supported by vascular structures, as well as laminin 511, a central constituent of basement membrane of brain blood vessels. Multi-targeted interference against β1, αV and α6 integrins expressed by U-251 and E-98 cells proved insufficient to achieve complete migration arrest. These data suggest that mechanocoupling by integrins is relatively resistant to antibody- or peptide-based targeting, and cooperates with additional, as yet unidentified adhesion systems in mediating glioma cell invasion in complex brain stroma.

Pharmacological Targeting of Cell Cycle, Apoptotic and Cell Adhesion Signaling Pathways Implicated in Chemoresistance of Cancer Cells

Chemotherapeutic drugs target a physiological differentiating feature of cancer cells as they tend to actively proliferate more than normal cells. They have well-known side-effects resulting from the death of highly proliferative normal cells in the gut and immune system. Cancer treatment has changed dramatically over the years owing to rapid advances in oncology research. Developments in cancer therapies, namely surgery, radiotherapy, cytotoxic chemotherapy and selective treatment methods due to better understanding of tumor characteristics, have significantly increased cancer survival. However, many chemotherapeutic regimes still fail, with 90% of the drug failures in metastatic cancer treatment due to chemoresistance, as cancer cells eventually develop resistance to chemotherapeutic drugs. Chemoresistance is caused through genetic mutations in various proteins involved in cellular mechanisms such as cell cycle, apoptosis and cell adhesion, and targeting those mechanisms could improve outcomes of cancer therapy. Recent developments in cancer treatment are focused on combination therapy, whereby cells are sensitized to chemotherapeutic agents using inhibitors of target pathways inducing chemoresistance thus, hopefully, overcoming the problems of drug resistance. In this review, we discuss the role of cell cycle, apoptosis and cell adhesion in cancer chemoresistance mechanisms, possible drugs to target these pathways and, thus, novel therapeutic approaches for cancer treatment.

Integrins as Therapeutic Targets: Successes and Cancers

Integrins are transmembrane receptors that are central to the biology of many human pathologies. Classically mediating cell-extracellular matrix and cell-cell interaction, and with an emerging role as local activators of TGFβ, they influence cancer, fibrosis, thrombosis and inflammation. Their ligand binding and some regulatory sites are extracellular and sensitive to pharmacological intervention, as proven by the clinical success of seven drugs targeting them. The six drugs on the market in 2016 generated revenues of some US$3.5 billion, mainly from inhibitors of α4-series integrins. In this review we examine the current developments in integrin therapeutics, especially in cancer, and comment on the health economic implications of these developments.

Interest of integrins targeting in glioblastoma according to tumor heterogeneity and cancer stem cell paradigm: an update

Glioblastomas are malignant brain tumors with dismal prognosis despite standard treatment with surgery and radio/chemotherapy. These tumors are defined by an important cellular heterogeneity and notably contain a particular subpopulation of Glioblastoma-initiating cells, which recapitulate the heterogeneity of the original Glioblastoma. In order to classify these heterogeneous tumors, genomic profiling has also been undertaken to classify these heterogeneous tumors into several subtypes. Current research focuses on developing therapies, which could take into account this cellular and genomic heterogeneity. Among these targets, integrins are the subject of numerous studies since these extracellular matrix transmembrane receptors notably controls tumor invasion and progression. Moreover, some of these integrins are considered as membrane markers for the Glioblastoma-initiating cells subpopulation. We reviewed here integrin expression according to glioblastoma molecular subtypes and cell heterogeneity. We discussed their roles in glioblastoma invasion, angiogenesis, therapeutic resistance, stemness and microenvironment modulations, and provide an overview of clinical trials investigating integrins in glioblastomas. This review highlights that specific integrins could be identified as selective glioblastoma cells markers and that their targeting represents new diagnostic and/or therapeutic strategies.

The cancer cell adhesion resistome: mechanisms, targeting and translational approaches

Cell adhesion-mediated resistance limits the success of cancer therapies and is a great obstacle to overcome in the clinic. Since the 1990s, where it became clear that adhesion of tumor cells to the extracellular matrix is an important mediator of therapy resistance, a lot of work has been conducted to understand the fundamental underlying mechanisms and two paradigms were deduced: cell adhesion-mediated radioresistance (CAM-RR) and cell adhesion-mediated drug resistance (CAM-DR). Preclinical work has evidently demonstrated that targeting of integrins, adapter proteins and associated kinases comprising the cell adhesion resistome is a promising strategy to sensitize cancer cells to both radiotherapy and chemotherapy. Moreover, the cell adhesion resistome fundamentally contributes to adaptation mechanisms induced by radiochemotherapy as well as molecular drugs to secure a balanced homeostasis of cancer cells for survival and growth. Intriguingly, this phenomenon provides a basis for synthetic lethal targeted therapies simultaneously administered to standard radiochemotherapy. In this review, we summarize current knowledge about the cell adhesion resistome and highlight targeting strategies to override CAM-RR and CAM-DR.

Peptidomimetic therapeutics: scientific approaches and opportunities

Natural endogenously occurring peptides exhibit desirable medicinal properties, but are often limited in application by rapid proteolysis and inadequate membrane permeability. However, editing naturally occurring peptide sequences to develop peptidomimetic analogs created a promising class of therapeutics that can augment or inhibit molecular interactions. Here, we discuss a variety of chemical modifications, including l to d isomerization, cyclization, and unnatural amino acid substitution, as well as design strategies, such as attachment to cell-penetrating peptides, which are used to develop peptidomimetics. We also provide examples of approved peptidomimetics and discuss several compounds in clinical trials.

Emerging targeted therapies for glioma

INTRODUCTION

Gliomas are the most common malignant primary brain tumors in adults. Despite aggressive treatment with surgery, radiation and chemotherapy, these tumors are incurable and invariably recur. Molecular characterization of these tumors in recent years has advanced our understanding of gliomagenesis and offered an array of pathways that can be specifically targeted. Areas covered: The most commonly dysregulated signaling pathways found in gliomas will be discussed, as well as the biologic importance of these disrupted pathways and how each may contribute to tumor development. Our knowledge regarding these pathways are most relevant to Grade IV glioma/glioblastoma, but we will also discuss genomic categorization of low grade glioma. Further, drugs targeting single pathways, which have undergone early phase clinical trials will be reviewed, followed by an in depth discussion of emerging treatments on the horizon, which will include inhibitors of Epidermal Growth Factor Receptor (EGFR) and receptor tyrosine kinases, Phosphoinositide-3-Kinase (PI3K), angiogenesis, cell cycle and mutant Isocitrate Dehydrogenase (IDH) mutations. Expert opinion: Results from single agent targeted therapy trials have been modest. Lack of efficacy may stem from a combination of poor blood brain barrier penetration, the genetically heterogeneous make-up of the tumors and the emergence of resistance mechanisms. These factors can be overcome by rational drug design that capitalizes on ways to target critical pathways and limits upregulation of redundant pathways.

The role of integrins in TGFβ activation in the tumour stroma

TGFβ1 is the most pleiotropic of all known cytokines and thus, to avoid uncontrolled TGFβ-activated processes, its activity is tightly regulated. Studies in fibrosis have led to the discovery that αv integrins are the major regulators of the local activation of latent TGFβ in our tissues. Since all cells can express one or more types of αv integrins, this raises the possibility that, in the complex milieu of a developing cancer, multiple cell types including both cancer cells and stromal cells activate TGFβ. In normal tissues, TGFβ1 is a tumour suppressor through its ability to suppress epithelial cell division, whereas in cancer, in which tumour cells develop genetic escape mechanisms to become resistant to TGFβ growth suppression, TGFβ signalling creates a tumour-permissive environment by activating fibroblast-to-myofibroblast transition, by promoting angiogenesis, by suppressing immune cell populations and by promoting the secretion of both matrix proteins and proteases. In addition, TGFβ drives epithelial-to-mesenchymal transition (EMT) increasing the potential for metastasis. Since αv integrins activate TGFβ, they almost certainly drive TGFβ-dependent cancer progression. In this review, we discuss the data that are helping to develop this hypothesis and describe the evidence that αv integrins regulate the TGFβ promotion of cancer. Graphical Abstract Mechanisms of integrin-mediated transforming growth factor beta (TGFβ) activation and its effect on stromal processes. 1 Matrix-bound latent LAP-TGFβ1 binds αv integrins expressed by epithelial cells or fibroblasts (LAP latency-associated peptide). TGFβ1 becomes exposed. 2 Active TGFβ1 binds the TGFβ receptor in an autocrine or paracrine fashion. 3 TGFβ1 signalling increases integrin expression, LAP-TGFβ1 secretion and trans-differentiation of fibroblasts into contractile cells that secrete collagens and collagen cross-linking proteins. By contracting the matrix, latent TGFβ1 is stretched making the activation of latent TGFβ1 easier and creating a continuous cycle of TGFβ1 signalling. TGFβ1 promotes cancer progression by promoting angiogenesis, immune suppression and epithelial-to-mesenchymal transition (EMT).