Annemiek M.E. Walenkamp

Single-agent bevacizumab or lomustine versus a combination of bevacizumab plus lomustine in patients with recurrent glioblastoma (BELOB trial): a randomised controlled phase 2 trial

BACKGROUND Treatment options for recurrent glioblastoma are scarce, with second-line chemotherapy showing only modest activity against the tumour. Despite the absence of well controlled trials, bevacizumab is widely used in the treatment of recurrent glioblastoma. Nonetheless, whether the high response rates reported after treatment with this drug translate into an overall survival benefit remains unclear. We report the results of the first randomised controlled phase 2 trial of bevacizumab in recurrent glioblastoma. METHODS The BELOB trial was an open-label, three-group, multicentre phase 2 study undertaken in 14 hospitals in the Netherlands. Adult patients (≥18 years of age) with a first recurrence of a glioblastoma after temozolomide chemoradiotherapy were randomly allocated by a web-based program to treatment with oral lomustine 110 mg/m(2) once every 6 weeks, intravenous bevacizumab 10 mg/kg once every 2 weeks, or combination treatment with lomustine 110 mg/m(2) every 6 weeks and bevacizumab 10 mg/kg every 2 weeks. Randomisation of patients was stratified with a minimisation procedure, in which the stratification factors were centre, Eastern Cooperative Oncology Group performance status, and age. The primary outcome was overall survival at 9 months, analysed by intention to treat. A safety analysis was planned after the first ten patients completed two cycles of 6 weeks in the combination treatment group. This trial is registered with the Nederlands Trial Register (www.trialregister.nl, number NTR1929). FINDINGS Between Dec 11, 2009, and Nov 10, 2011, 153 patients were enrolled. The preplanned safety analysis was done after eight patients had been treated, because of haematological adverse events (three patients had grade 3 thrombocytopenia and two had grade 4 thrombocytopenia) which reduced bevacizumab dose intensity; the lomustine dose in the combination treatment group was thereafter reduced to 90 mg/m(2). Thus, in addition to the eight patients who were randomly assigned to receive bevacizumab plus lomustine 110 mg/m(2), 51 patients were assigned to receive bevacizumab alone, 47 to receive lomustine alone, and 47 to receive bevacizumab plus lomustine 90 mg/m(2). Of these patients, 50 in the bevacizumab alone group, 46 in the lomustine alone group, and 44 in the bevacizumab and lomustine 90 mg/m(2) group were eligible for analyses. 9-month overall survival was 43% (95% CI 29-57) in the lomustine group, 38% (25-51) in the bevacizumab group, 59% (43-72) in the bevacizumab and lomustine 90 mg/m(2) group, 87% (39-98) in the bevacizumab and lomustine 110 mg/m(2) group, and 63% (49-75) for the combined bevacizumab and lomustine groups. After the reduction in lomustine dose in the combination group, the combined treatment was well tolerated. The most frequent grade 3 or worse toxicities were hypertension (13 [26%] of 50 patients in the bevacizumab group, three [7%] of 46 in the lomustine group, and 11 [25%] of 44 in the bevacizumab and lomustine 90 mg/m(2) group), fatigue (two [4%], four [9%], and eight [18%]), and infections (three [6%], two [4%], and five [11%]). At the time of this analysis, 144/148 (97%) of patients had died and three (2%) were still on treatment. INTERPRETATION The combination of bevacizumab and lomustine met prespecified criteria for assessment of this treatment in further phase 3 studies. However, the results in the bevacizumab alone group do not justify further studies of this treatment. FUNDING Roche Nederland and KWF Kankerbestrijding.

A review on CXCR4/CXCL12 axis in oncology : No place to hide

Classical chemotherapeutic anti-cancer treatments induce cell death through DNA damage by taking advantage of the proliferative behaviour of cancer cells. The more recent approach of targeted therapy (usually protein-targeted) has led to many treatments that are currently available or are under development, all of which are designed to strike at the critical driving forces of cancer cells. The interaction of the cancer cells with their microenvironment is one of these fundamental features of neoplasms that could be targeted in such cancer treatments. Haematological and solid tumour cells interact with their microenvironment through membrane chemokine receptors and their corresponding ligands, which are expressed in the tumour microenvironment. Important representatives of this system are the chemokine ligand CXCL12 and its receptor chemokine receptor 4 (CXCR4). This interaction can be disrupted by CXCR4 antagonists, and this concept is being used clinically to harvest haematopoietic stem/progenitor cells from bone marrow. CXCR4 and CXCL12 also have roles in tumour growth and metastasis, and more recently their roles in cancer cell-tumour microenvironment interaction and angiogenesis have been studied. Our review focuses on these roles and summarises strategies for treating cancer by disrupting this interaction with special emphasis on the CXCR4/CXCL12 axis. Finally, we discuss ongoing clinical trials with several classes of CXCR4 inhibitors, and their potential additive value for patients with a (therapy resistant) malignancy by sensitising cancer cells to conventional therapy.

Clinical and therapeutic aspects of extrapulmonary small cell carcinoma

Extrapulmonary small cell carcinoma (EPSCC) is usually treated similarly to small cell lung cancer. Differences in aetiology, clinical course, frequency of brain metastases, and survival, however, warrant a differential therapeutic approach. In this review, we focus on the treatment of the most predominant sites of origin of EPSCC; the gastrointestinal tract, the genitourinary tract, the head and neck region, and small cell carcinoma of unknown primary. Furthermore we review the available data concerning the controversial issue of prophylactic cranial irradiation (PCI) after optimal treatment of EPSCC. We found in the literature a significant lower incidence of brain metastases in EPSCC as compared to pulmonary small cell carcinoma when PCI is omitted and therefore we do not recommend PCI. An exception is EPSCC originating from the head and neck region which is associated with a higher incidence of brain metastasis, justifying addition of PCI.

Value of 11C-methionine PET in imaging brain tumours and metastases

Abstract11C-methionine (MET) is the most popular amino acid tracer used in PET imaging of brain tumours. Because of its characteristics, MET PET provides a high detection rate of brain tumours and good lesion delineation. This review focuses on the role of MET PET in imaging cerebral gliomas. The Introduction provides a clinical overview of what is important in primary brain tumours, recurrent brain tumours and brain metastases. The indications for radiotherapy and the results and problems arising after chemoradiotherapy in relation to imaging (pseudoprogression or radionecrosis) are discussed. The working mechanism, scan interpretation and quantification possibilities of MET PET are then explained. A literature overview is given of the role of MET PET in primary gliomas (diagnostic accuracy, grading, prognosis, assessment of tumour extent, biopsy and radiotherapy planning), in brain metastases, and in the differentiation between tumour recurrence and radiation necrosis. Finally, MET PET is compared to other nuclear imaging possibilities in brain tumour imaging.

TGF-β as a therapeutic target in high grade gliomas – Promises and challenges ☆

Transforming growth factor-β (TGF-β) is a cytokine with a key role in tissue homeostasis and cancer. TGF-β elicits both tumor suppressive and tumor promoting functions during cancer progression, in a wide range of cancers. Here, we review the tumor promoting function of TGF-β and its possible promise as a therapeutic target in high grade gliomas, including glioblastoma multiforme (GBM), a disease with very poor prognosis. TGF-β signaling is highly active in high grade gliomas and elevated TGF-β activity has been associated with poor clinical outcome in this deadly disease. Common features of GBMs include fast cell proliferation, invasion into normal brain parenchyma, hypoxia, high angiogenic - and immunosuppressive activity, characteristics that all have been linked to activation of the TGF-β pathway. TGF-β signaling has also been connected with the cancer stem cell (CSC) phenotype in GBM. CSCs represent a subset of GBM cells thought to be responsible for tumor initiation, progression and relapse of disease. Following the description of these different properties of TGF-β signaling and the underlying mechanisms identified thus far, the promise of TGF-β targeted therapy in malignant gliomas is discussed. Several drugs targeting TGF-β signaling have been developed that showed potent antitumor activity in preclinical models. A number of agents are currently evaluated in early clinical studies in glioma patients. Available results of these studies are highlighted and a perspective on the promise of TGF-β-targeted therapy is given.

Staphylococcal SSL5 inhibits leukocyte activation by chemokines and anaphylatoxins

Staphylococcus aureus secretes several virulence factors modulating immune responses. Staphylococcal superantigen-like (SSL) proteins are a family of 14 exotoxins with homology to superantigens, but with generally unknown function. Recently, we showed that SSL5 binds to P-selectin glycoprotein ligand 1 dependently of sialyl Lewis X and inhibits P-selectin-dependent neutrophil rolling. Here, we show that SSL5 potently and specifically inhibits leukocyte activation by anaphylatoxins and all classes of chemokines. SSL5 inhibited calcium mobilization, actin polymerization, and chemotaxis induced by chemokines and anaphylatoxins but not by other chemoattractants. Antibody competition experiments showed that SSL5 targets several chemokine and anaphylatoxin receptors. In addition, transfection studies showed that SSL5 binds glycosylated N-termini of all G protein-coupled receptors (GPCRs) but only inhibits stimuli of protein nature that require the receptor N-terminus for activation. Furthermore, SSL5 increased binding of chemokines to cells independent of chemokine receptors through their common glycosaminoglycan-binding site. Importance of glycans was shown for both GPCR and chemokine binding. Thus, SSL5 is an important immunomodulatory protein of S aureus that targets several crucial, initial stages of leukocyte extravasation. It is therefore a potential new antiinflammatory compound for diseases associated with chemoattractants and their receptors and disorders characterized by excessive recruitment of leukocytes.

Translating TRAIL-receptor targeting agents to the clinic

The extrinsic apoptotic pathway can be activated by the endogenous ligand TRAIL (Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand) by binding to the death receptors TRAIL-R1 and TRAIL-R2 on the cell surface. This pathway is currently evaluated as an anticancer treatment strategy. Both recombinant human TRAIL and several agonistic antibodies against TRAIL-R1 and R2 have been studied in single agent and combination studies and proved to be safe and well tolerated. In this article, the clinical studies published to date will be reviewed. Also, future perspectives and biomarker studies for selecting patients that will benefit from these agents will be discussed.

Potent Inhibition of Neutrophil Migration by Cryptococcal Mannoprotein-4-Induced Desensitization

Cryptococcal capsular Ags induce the production of proinflammatory cytokines in patients with cryptococcal meningitis. Despite this, their cerebrospinal fluid typically contains few neutrophils. Capsular glucuronoxylomannan is generally considered to mediate the inhibition of neutrophil extravasation. In the current study, culture supernatant harvested from the nonglucuronoxylomannan-producing strain CAP67 was found to be as potent as supernatant from wild-type strains in preventing migration. We identified capsular mannoprotein (MP)-4 as the causative agent. Purified MP-4 inhibited migration of neutrophils toward platelet-activating factor, IL-8, and fMLP, probably via a mechanism involving chemoattractant receptor cross-desensitization, as suggested by its direct chemotactic activity. Supporting this hypothesis, MP-4 elicited Ca2+ transients that were inhibited by preincubation with either fMLP, IL-8, or C5a, but not platelet-activating factor, and vice versa. Moreover, MP-4 strongly decreased the neutrophil surface expression of L-selectin and induced shedding of TNF receptors p55/p75, whereas CD11b/18 increased. Finally, MP-4 was clearly detectable in both serum and cerebrospinal fluid of patients suffering from cryptococcal meningitis. These findings identify MP-4 as a novel capsular Ag prematurely activating neutrophils and desensitizing them toward a chemoattractant challenge.

TGF- β is an inducer of ZEB1-dependent mesenchymal transdifferentiation in glioblastoma that is associated with tumor invasion

Different molecular subtypes of glioblastoma (GBM) have been recently identified, of which the mesenchymal subtype is associated with worst prognoses. Here, we report that transforming growth factor-β (TGF-β) is able to induce a mesenchymal phenotype in GBM that involves activation of SMAD2 and ZEB1, a known transcriptional inducer of mesenchymal transition in epithelial cancers. TGF-β exposure of established and newly generated GBM cell lines was associated with morphological changes, enhanced mesenchymal marker expression, migration and invasion in vitro and in an orthotopic mouse model. TGF-β-induced mesenchymal differentiation and invasive behavior was prevented by chemical inhibition of TGF-β signaling as well as small interfering RNA (siRNA)-dependent silencing of ZEB1. Furthermore, TGF-β-responding and -nonresponding GBM neurospheres were identified in vitro. Interestingly, nonresponding cells displayed already high levels of pSMAD2 and ZEB1 that could not be suppressed by inhibition of TGF-β signaling, suggesting the involvement of yet unknown mechanisms. These different GBM neurospheres formed invasive tumors in mice as well as revealed mesenchymal marker expression in immunohistochemical analyses. Moreover, we also detected distinct zones with overlapping pSMAD2, elevated ZEB1 and mesenchymal marker expression in GBM patient material, suggestive of the induction of local, microenvironment-dependent mesenchymal differentiation. Overall, our findings indicate that GBM cells can acquire mesenchymal features associated with enhanced invasive potential following stimulation by secretory cytokines, such as TGF-β. This property of GBM contributes to heterogeneity in this tumor type and may blur the boundaries between the proposed transcriptional subtypes. Targeting TGF-β or downstream targets like ZEB1 might be of potential benefit in reducing the invasive phenotype of GBM in a subpopulation of patients.

Rectal and colon cancer : Not just a different anatomic site

Due to differences in anatomy, primary rectal and colon cancer require different staging procedures, different neo-adjuvant treatment and different surgical approaches. For example, neoadjuvant radiotherapy or chemoradiotherapy is administered solely for rectal cancer. Neoadjuvant therapy and total mesorectal excision for rectal cancer might be responsible in part for the differing effect of adjuvant systemic treatment on overall survival, which is more evident in colon cancer than in rectal cancer. Apart from anatomic divergences, rectal and colon cancer also differ in their embryological origin and metastatic patterns. Moreover, they harbor a different composition of drug targets, such as v-raf murine sarcoma viral oncogene homolog B (BRAF), which is preferentially mutated in proximal colon cancers, and the epidermal growth factor receptor (EGFR), which is prevalently amplified or overexpressed in distal colorectal cancers. Despite their differences in metastatic pattern, composition of drug targets and earlier local treatment, metastatic rectal and colon cancer are, however, commonly regarded as one entity and are treated alike. In this review, we focused on rectal cancer and its biological and clinical differences and similarities relative to colon cancer. These aspects are crucial because they influence the current staging and treatment of these cancers, and might influence the design of future trials with targeted drugs.