Integrin Inhibitor Cilengitide Research Articles

Cancer-associated fibroblasts confer ALK inhibitor resistance in EML4-ALK -driven lung cancer via concurrent integrin and MET signaling.

Cancer-associated fibroblasts (CAFs) are associated with tumor progression and modulate drug sensitivity of cancer cells. However, the underlying mechanisms are often incompletely understood and crosstalk between tumor cells and CAFs involves soluble secreted as well as adhesion proteins. Interrogating a panel of non-small cell lung cancer (NSCLC) cell lines driven by EML4-ALK fusions, we observed substantial CAF-mediated drug resistance to clinical ALK tyrosine kinase inhibitors (TKIs). Array-based cytokine profiling of fibroblast-derived conditioned- media identified HGF-MET signaling as a major contributor to CAF-mediated paracrine resistance that can be overcome by MET TKIs. However, 'Cell Type specific labeling using Amino acid Precursors' (CTAP)-based expression and phosphoproteomics in direct coculture also highlighted a critical role for the fibronectin-integrin pathway. Flow cytometry analysis confirmed activation of integrin β1 (ITGB1) in lung cancer cells by CAF coculture. Treatment with pharmacological inhibitors, cancer cell-specific silencing or CRISPR-Cas9-mediated knockout of ITGB1 overcame adhesion protein-mediated resistance. Concurrent targeting of MET and integrin signaling effectively abrogated CAF-mediated resistance of EML4-ALK -driven NSCLC cells to ALK TKIs in vitro . Consistently, combination of the ALK TKI alectinib with the MET TKI capmatinib and/or the integrin inhibitor cilengitide was significantly more efficacious than single agent treatment in suppressing tumor growth using an in vivo EML4-ALK -dependent allograft mouse model of NSCLC. In summary, these findings emphasize the complexity of resistance-associated crosstalk between CAFs and cancer cells, which can involve multiple concurrent signaling pathways, and illustrate how comprehensive elucidation of paracrine and juxtacrine resistance mechanisms can inform on more effective therapeutic approaches.

Abstract 2022: AlphaV Integrins Inhibition Downregulates Pro-fibrotic Events In Human Aortic Smooth Muscle Cells And Limits Thoracic Aortic Aneurysm Progression In Marfan Mice

Aortic dilation can often lead to lethal events, such as aortic dissection and/or vessel rupture. The aneurysms occurring in the thoracic aortic trait (TAA) may depend on comorbidities, such as hypertension, or on genetically determined conditions, such as Marfan syndrome (MFS). To date, the surgical replacement of aorta represents the most effective therapeutic approach in all TAA patients, since an etiologic pharmacological treatment is still lacking. Integrin receptors are key players in cellular mechanotransduction responses and the role of integrins containing αV subunit have been described as responsible for pro-fibrotic molecular events. Recently, it has been reported the effectiveness of a pan αV integrin inhibitor ( i.e. , GLPG0187) in limiting the TAA progression in MFS in vivo model. However, the specific αV integrin subgroup directly involved in this detrimental process is yet not known. We evaluated the effectiveness of the specific αVβ3 and αVβ5 integrin inhibitor cilengitide in downregulating pro-fibrotic in vitro events on MFS patients’ vascular smooth muscle cells (MFS-VSMC), and in limiting in vivo thoracic aortic dilation on a MFS mice model. By comparison with healthy control (HC)-VSMC, MFS-VSMC showed higher levels of αVβ3 and αVβ5 integrins as well as pro-fibrotic collagen I. When compared with GLPG0187, the cilengitide-mediated in vitro inhibition of these integrins determined a more effective downregulation of TGF-β downstream pathways (SMAD2/3 and ERK1/2) as well as a statistical tempered expression of pro-fibrotic mechanotransduction mediators, such as RhoA GTPase. The 2D-echocardiographic results on MFS mice (Fbn1 C1039G/+ ) treated with cilengitide confirmed the greater effectiveness of this drug in limiting the TAA progression, not only in comparison with vehicle but also with the broad pan αV integrin inhibitor GLPG0187. Altogether, our results improve the know-how on αV integrin involvement in MFS-TAA scenario, unveiling the specific detrimental role of αVβ3 and αVβ5 in this pathological context. The selective inhibition of these integrins exerted by cilengitide highlights the role of this compound as a potential and more targeted tool for future therapeutic approaches to limit TAA progression in MFS patients.

Treatment-associated imaging changes in newly diagnosed MGMT promoter-methylated glioblastoma undergoing chemoradiation with or without cilengitide.

Radiological progression may originate from progressive disease (PD) or pseudoprogression/treatment-associated changes. We assessed radiological progression in O6-methylguanine-DNA methyltransferase (MGMT) promoter-methylated glioblastoma treated with standard-of-care chemoradiotherapy with or without the integrin inhibitor cilengitide according to the modified response assessment in neuro-oncology (RANO) criteria of 2017. Patients with ≥ 3 follow-up MRIs were included. Preliminary PD was defined as a ≥ 25% increase of the sum of products of perpendicular diameters (SPD) of a new or increasing lesion compared to baseline. PD required a second ≥25% increase of the SPD. Treatment-associated changes require stable or regressing disease after preliminary PD. Of the 424 evaluable patients, 221 patients (52%) were randomized into the cilengitide and 203 patients (48%) into the control arm. After chemoradiation with or without cilengitide, preliminary PD occurred in 274 patients (65%) during available follow-up, and 88 of these patients (32%) had treatment-associated changes, whereas 67 patients (25%) had PD. The remaining 119 patients (43%) had no further follow-up after preliminary PD. Treatment-associated changes were more common in the cilengitide arm than in the standard-of-care arm (24% vs. 17%; relative risk, 1.3; 95% CI, 1.004-1.795; P = .047). Treatment-associated changes occurred mainly during the first 6 months after RT (54% after 3 months vs. 13% after 6 months). With the modified RANO criteria, the rate of treatment-associated changes was low compared to previous studies in MGMT promoter-methylated glioblastoma. This rate was higher after cilengitide compared to standard-of-care treatment. Confirmatory scans, as recommended in the modified RANO criteria, were not always available reflecting current clinical practice.

The Integrin Inhibitor Cilengitide and Bleomycin-Induced Pulmonary Fibrosis : Cilengitide and Bleomycin-Induced Pulmonary Fibrosis.

Fibroproliferation and excess deposition of extracellular matrix (ECM) are the pathologic hallmarks of idiopathic pulmonary fibrosis (IPF), a chronic progressive disorder with high mortality and suboptimal treatment options. Although the etiologic mechanisms responsible for the development and progression of IPF remain unclear, cell-ECM interactions and growth factors are considered important. Cilengitide is a cyclic RGD pentapeptide with anti-angiogenic activity that targets αvβ3, αvβ5 and α5β1, integrins known to mediate cell-ECM interactions and activate the pro-fibrotic growth factor Transforming Growth Factor beta (TGF-β). Cilengitide was studied in vitro with the use of NIH/3T3 cells and primary lung fibroblasts, and in vivo in the well-characterized bleomycin-induced lung injury model. The extent of ECM deposition was determined by RT-PCR, Western blot, histologic analysis and hydroxyproline assay of lung tissue. Bronchoalveolar lavage analysis was used to determine cell counts. Cilengitide treatment of cultured fibroblasts showed decreased adhesion to vitronectin and fibronectin, both integrin-dependent events. Cilengitide also inhibited TGF-β-induced fibronectin gene expression and reduced the accumulation of mRNAs and protein for fibronectin and collagen type I. Both preventive and treatment effects of daily injections of cilengitide (20mg/kg) failed to inhibit the development of pulmonary fibrosis as determined by histological analysis (Ashcroft scoring), bronchoalveolar lavage (BAL) fluid cell counts, and hydroxyproline content. Overall, our data suggest that, despite its in vitro activity in fibroblasts, daily injections of cilengitide (20mg/kg) did not inhibit the development of or ameliorate bleomycin-induced pulmonary fibrosis in mice.

A comparative assessment of the effects of integrin inhibitor cilengitide on primary culture of head and neck squamous cell carcinoma (HNSCC) and HNSCC cell lines

Integrins are highly attractive targets in oncology due to their involvement in angiogenesis in a wide spectrum of cancer entities. Among several integrin inhibitors, cilengitide is suggested to be one of the most promising inhibitors. However, little is known about the cellular processes induced during cilengitide chemotherapy in head and neck squamous cell carcinoma (HNSCC). For the current study, 3 HNSCC cell lines, SCC4, SCC15 and SCC25; and 3 primary culture cells, TU53, TU57, and TU63 were used. CD90, cytokeratin, and vimentin were stained immunohistochemically to identify the biological characteristics of these cell lines and primary culture cells and the cytostatic effect of cilengitide was evaluated. Quantitative polymerase chain reaction (qPCR) arrays were applied to evaluate target protein genes ITGAV, ITGB3, and ITGB5 of integrin αvβ3 and αvβ5 at respective concentrations of 50 and 100μM cilengitide for 72h. Cilengitide has significantly inhibited the proliferation of HNSCC cells in a dose-dependent way. At the same concentration, cilengitide suppressed the proliferation of primary culture cells even more strongly than it did that of cell lines, suggesting that primary culture cells retain more of their internal biological characteristics than do cell lines. qPCR assay detected downregulation of ITGAV, ITGB3, and ITGB5 gene expression after exposure to 50μM of cilengitide. However, after exposure to 100-μM cilengitide, expression of these genes significantly increased both in cell lines and primary culture cells. RGD-containing small-molecule synthetic peptides might be considered in tumor chemotherapy in the near future. The different reactions of primary culture cells and cell lines demonstrated that individualized chemotherapy plans may be a feasible option. However, research on the role of cilengitide in HNSCC therapy is still in its early stages, and further investigations are required.

CD44 drives aggressiveness and chemoresistance of a metastatic human osteosarcoma xenograft model.

BackgroundOsteosarcoma is the most common primary malignant bone tumor with a 5 year survival rate of up to 70%. However, patients with metastatic disease have still a very poor prognosis. Osteosarcoma metastasis models are essential to develop novel treatment strategies for advanced disease.MethodsBased on a serial transplantation approach, we have established a U-2 OS osteosarcoma xenograft model with increased metastatic potential and compared it to other metastatic osteosarcoma models from international sources. Subclones with differing invasive potential were compared for genomic gains and losses as well as gene expression changes by several bioinformatic approaches. Based on the acquired results, the effects of a shRNA-mediated CD44 mRNA knockdown on migration, invasion and chemosensitivity were evaluated.ResultsThe CD44 gene was part of an amplified region at chromosome 11p found in both U-2 OS subclones with enhanced metastatic potential but not in parental U-2 OS cells, corresponding with distinct CD44 overexpression. Accordingly, shRNA-mediated CD44 knockdown significantly attenuated osteosarcoma cell migration, invasion, and viability especially in the metastatic subclones of U-2 OS and Saos-2 cells. Metastatic subclones generally were hypersensitive against the integrin inhibitor cilengitide paralleled by alterations in integrin expression pattern following CD44 knock-down. Additionally, attenuation of CD44 expression sensitized these cell models against osteosarcoma chemotherapy with doxorubicin but not methotrexate and cisplatin.ConclusionsThe osteosarcoma xenograft models with increased metastatic potential developed in this study can be useful for identification of mechanisms driving metastasis and resistance towards clinically used and novel therapeutic regimens.

Continuous Infusion of Cilengitide Plus Chemoradiotherapy for Patients With Stage III Non–Small-cell Lung Cancer: A Phase I Study

IntroductionBecause of our previous preclinical results, we conducted a phase I study associating the specific αvβ3/αvβ5 integrin inhibitor cilengitide, given as a continuous infusion, with exclusive chemoradiotherapy for patients with stage III non–small-cell lung cancer. Patients and MethodsA standard 3+3 dose escalation design was used. Cilengitide was given as a continuous infusion (dose levels of 12, 18, 27, and 40 mg/h), starting 2 weeks before and continuing for the whole course of chemoradiotherapy (66 Gy combined with platinum/vinorelbine), and then at a dose of 2000 mg twice weekly in association with chemotherapy. 2-Deoxy-2-[fluorine-18]fluoro-d-glucose positron emission tomography (PET) and computed tomography scans were performed before and after the first 2 weeks of cilengitide administration and then every 3 months. ResultsOf the 14 patients included, 11 were evaluable for evaluation of the dose-limiting toxicities (DLTs). One DLT, a tracheobronchial fistula, was reported with the 40 mg/h dose. No relevant adverse events related to cilengitide were observed overall. At the PET evaluation 2 months after chemoradiotherapy, 4 of 9 patients had a complete response and 4 had a partial response. The median progression-free and overall survival was 14.4 months (95% confidence interval [CI], 8.4 to not reached) and 29.4 months (95% CI, 11.73 to not reached), respectively. ConclusionCilengitide, given continuously with chemoradiotherapy, showed acceptable toxicity and gave encouraging clinical results.

Periostin promotes migration, proliferation, and differentiation of human periodontal ligament mesenchymal stem cells

ABSTRACTOverview: Periostin (POSTN) is critical to bone and dental tissue morphogenesis, postnatal development, and maintenance; however, its roles in tissue repair and regeneration mediated by human periodontal ligament mesenchymal stem cells (PDLSCs) remain unclear. The present study was designed to evaluate the effects of POSTN on hPDLSCs in vitro. Materials and Methods: hPDLSCs were isolated and characterized by their expression of the cell surface markers CD44, CD90, CD105, CD34, and CD45. Next, 100 ng/mL recombinant human POSTN protein (rhPOSTN) was used to stimulate the hPDLSCs. Lentiviral POSTN shRNA was used to knockdown POSTN. The cell counting kit-8 (CCK8) and scratch assay were used to analyze cell proliferation and migration, respectively. Osteogenic differentiation was investigated using an alkaline phosphatase (ALP) activity assay, alizarin staining, and quantitative calcium analysis and related genes/protein expression assays. Results: Isolated hPDLSCs were positive for CD44, CD90, and CD105 and negative for CD34 and CD45. In addition, 100 ng/mL rhPOSTN significantly accelerated scratch closure, and POSTN-knockdown cells presented slower closure at 24 h and 48 h. Furthermore, the integrin inhibitor Cilengitide depressed the scratch closure that was enhanced by POSTN at 24 h. The CCK8 assay showed that 100 ng/mL rhPOSTN promoted hPDLSC proliferation. Moreover, 100 ng/mL rhPOSTN increased the expression of RUNX2, OSX, OPN, OCN, and VEGF and enhanced ALP activity and mineralization. POSTN silencing decreased the expression of RUNX2, OSX, OPN, OCN, and VEGF and inhibited ALP activity and mineralization. Conclusions: POSTN accelerated the migration, proliferation, and osteogenic differentiation of hPDLSCs.

Complement-activated vitronectin enhances the invasion of nonphagocytic cells by bacterial pathogens Burkholderia and Klebsiella.

Burkholderia pseudomallei is a serum-resistant Gram-negative bacterium capable of causing disseminated infections with metastatic complications. However, its interaction with nonphagocytic cells is poorly understood. We observed that exposure of B. pseudomallei and the closely related yet avirulent B. thailandensis to human plasma increased epithelial cell invasion by >20 fold. Enhanced invasion was primarily driven by a plasma factor, which required a functional complement cascade, but surprisingly, was downstream of C3 mediated opsonisation. Receptor blocking studies with RGD-domain containing peptide and αV β3 blocking antibody identified complement-activated vitronectin as the factor facilitating this invasion. Plasma treatment led to the recruitment of vitronectin onto the bacterial surface, and its conversion into the active conformation. Activation of vitronectin, as well as increased invasion, required the complement pathway and was not observed in C3 or C5 depleted serum. The integrin inhibitor cilengitide, currently in clinical trials as an anti-angiogenesis agent, suppresses plasma-mediated Burkholderia invasion by ~95%, along with a downstream reduction in intracellular bacterial replication. We extend these findings to serum-resistant Klebsiella pneumoniae as well. Thus, the potential use of commercially available integrin inhibitors as anti-infective agents during selective bacterial infections should be explored.

Small-molecule inhibitors of FGFR, integrins and FAK selectively decrease L1CAM-stimulated glioblastoma cell motility and proliferation.

The cell adhesion/recognition protein L1CAM (L1; CD171) has previously been shown to act through integrin, focal adhesion kinase (FAK) and fibroblast growth factor receptor (FGFR) signaling pathways to increase the motility and proliferation of glioblastoma cells in an autocrine/paracrine manner. Here, we investigated the effects of clinically relevant small-molecule inhibitors of the integrin, FAK and FGFR signaling pathways on glioblastoma-derived cells to determine their effectiveness and selectivity for diminishing L1-mediated stimulation. The effects of the FGFR inhibitor PD173074, the FAK inhibitors PF431396 and Y15 and the αvβ3/αvβ5 integrin inhibitor cilengitide were assessedin L1-positive and L1-negative variants of the human glioblastoma-derived cell lines T98G and U-118 MG. Their motility and proliferation were quantified using time-lapse microscopy and DNA content/cell cycle analyses, respectively. The application of all four inhibitors resulted in reductions in L1-mediated motility and proliferation rates of L1-positive glioblastoma-derived cells, down to the level of L1-negative cells when used at nanomolar concentrations, whereas no or much smaller reductions in these rates were obtained in L1-negative cells. In addition, we found that single inhibitor treatment resulted in maximum effects (i.e., combinations of FAK or integrin inhibitors with the FGFR inhibitor were rarely more effective). These results suggest that FAK may act as a point of convergence between the integrin and FGFR signaling pathways stimulated by L1 in these cells. We here show for the first time that small-molecule inhibitors of FGFR, integrins and FAK effectively and selectively abolish L1-stimulated migration and proliferation of glioblastoma-derived cells. Our results suggest that these inhibitors have the potential to reduce the aggressiveness of high-grade gliomas expressing L1.

The role of integrins in glioma biology and anti-glioma therapies.

Integrins are a group of molecules expressed by various cells including glioma cells and endothelial cells within the tumor. There are 18 known alpha and beta integrin subunits which form a heterodimer. Integrins regulate different cellular processes such as proliferation, adhesion, motility and survival as shown in numerous preclinical models. Furthermore, integrins control the activity of the transforming growth factor (TGF)-beta pathway and are involved in the process of angiogenesis which is indispensable for continued tumor growth. Because of the high expression levels of some integrins on glioma cells and their numerous functions, inhibition of integrin signaling has been considered a promising strategy for the treatment of glioma patients. Besides blocking antibodies which are currently under clinical investigation in other cancer entities, the integrin inhibitor cilengitide has been tested within several trials in glioblastoma patients over the last years. Cilengitide is a cyclic RDG peptide which targets integrins alphvbeta3 and alphavbeta5. Based on the results of smaller, initial trials suggesting an activity of cilengitide against glioblastoma, 2 larger trials were subsequently performed. However, both trials, which combined temozolomide-based chemoradiation with cilengitide failed to demonstrate an improved outcome with the addition of cilengitide. Ongoing translational analyses suggest that integrin levels in the tumor tissue are neither prognostic nor predict response to cilengitide. While the clinical development of cilengitide has been stopped, integrin inhibition with more effective agents may still be a promising approach in clinical neurooncology.

Cilengitide downmodulates invasiveness and vasculogenic mimicry of neuropilin 1 expressing melanoma cells through the inhibition of αvβ5 integrin.

During melanoma progression, tumour cells show increased adhesiveness to the vascular wall, invade the extracellular matrix (ECM) and frequently form functional channels similar to vascular vessels (vasculogenic mimicry). These properties are mainly mediated by the interaction of integrins with ECM components. Since we had previously identified neuropilin 1 (NRP-1), a coreceptor of vascular endothelial growth factor A (VEGF-A), as an important determinant of melanoma aggressiveness, aims of this study were to identify the specific integrins involved in the highly invasive phenotype of NRP-1 expressing cells and to investigate their role as targets to counteract melanoma progression. Melanoma aggressiveness was evaluated in vitro as cell ability to migrate through an ECM layer and to form tubule-like structures using transfected cells. Integrins relevant to these processes were identified using specific blocking antibodies. The αvβ5 integrin was found to be responsible for about 80% of the capability of NRP-1 expressing cells to adhere on vitronectin. In these cells αvβ5 expression level was twice higher than in low-invasive control cells and contributed to the ability of melanoma cells to form tubule-like structures on matrigel. Cilengitide, a potent inhibitor of αν integrins activation, reduced ECM invasion, vasculogenic mimicry and secretion of VEGF-A and metalloproteinase 9 by melanoma cells. In conclusion, we demonstrated that ανβ5 integrin is involved in the highly aggressive phenotype of melanoma cells expressing NRP-1. Moreover, we identified a novel mechanism that contributes to the antimelanoma activity of the αv integrin inhibitor cilengitide based on the inhibition of vasculogenic mimicry.

Continuous Infusion of Cilengitide with Radio-Chemotherapy in Stage III Nsclc: a Phase I Study

ABSTRACT Aim: We have shown that avb3 integrins control radioresistance, hypoxia and angiogenesis and that co-expression of FGF-2 and avb3 integrins in the tumors of patients treated with exclusive radio-chemotherapy for stage III non-small lung carcinoma (NSCLC), was associated with a worse local control, suggesting that inhibition of avb3 integrin could induce a radiosensitization of such tumours. We designed a phase I trial associating the specific avb3/avb5 integrin inhibitor cilengitide with radio-chemotherapy in patients with stage III NSCLC. Methods: A standard 3 + 3 dose escalation design was used. Cilengitide was given in continuous infusion starting 2 weeks before and then during the whole course of the radio-chemotherapy (66 Gy combined with a Platine-Navelbine regimen), and then at a dose of 2000 mg twice a week in association with chemotherapy. Planed Cilengitide continuous infusion dose levels were 12, 18, 27 and 40 mg/h. PET-FDG and CT scan were performed before and then after the first two weeks of Cilengitide administration and then 2 months after the end of radio-chemotherapy. Patients were followed by CT scan. Toxicity for DLT was assessed during combined treatment and until 1 month after. Clinical response on CT scan and TEP was evaluated according to RECIST and PERCIST criteria. Results: Fourteen patients were included between March 2010 and July 2013. Eleven patients were evaluable for DLT. No DLT was observed at level 0, 1 and 2. One DLT, a tracheo-bronchial fistula was reported at the 40 mg/h dose. No relevant adverse event related to Cilengitide (7 grade 1 and one grade 2) was observed on the whole population. Among 11 patients evaluable for efficacy, 9 patients presented a partial response and 2 a stable disease. At 6 months after the end of radio-chemotherapy, 2 patients presented a progressive disease. At PET evaluation 2 months after radio-chemotherapy, 4 patients had a complete response and 4 patients had a partial response. Conclusions: Cilengitide given continuously with radio-chemotherapy was well tolerated and shows encouraging clinical results, suggesting that targeting avb3 integrin continuously during radio-chemotherapy in NSCLC is a promising approach to treat this disease. Disclosure: E.L. Cohen-Jonathan Moyal: E Moyal has been member of an advisory board for Merck KGaA and received a funding grant from Merck KGaA for research. All other authors have declared no conflicts of interest.

Radiotherapy (RT), temozolomide (TMZ), procarbazine (PCB), and the integrin inhibitor cilengitide in patients (pts) with glioblastoma (GBM) without methylation of the MGMT gene promoter (ExCentric): Results of an Australian phase II clinical trial.

2050^ Background: Building on our preclinical data, we proposed that combination of low dose TMZ and PCB may overcome TMZ chemoresistance in MGMT unmethylated GBM. We proposed adding Cilengitide, a...

The Integrin Inhibitor Cilengitide Affects Meningioma Cell Motility and Invasion

Meningiomas are frequent intracranial or spinal neoplasms, which recur frequently and can show aggressive clinical behaviour. We elucidated the impact of the integrin inhibitor cilengitide on migration, proliferation, and radiosensitization of meningioma cells. We analyzed integrin expression in tissue microarrays of human meningiomas and the antimeningioma properties of cilengitide in cell cultures, subcutaneous and intracranial nude mouse models by measuring tumor volumes and survival times. αvβ5 was the predominantly expressed integrin heterodimer in meningiomas, whereas αvβ3 was mainly detected in tumor blood vessels. Application of up to 100 μg/mL cilengitide resulted in only mildly reduced proliferation/survival of meningioma cell lines. Effects on cell survival could be enhanced by irradiation. One μg/mL cilengitide was sufficient to significantly inhibit meningioma cell migration and invasion in vitro. A daily dosage of 75 mg/kg did neither affect tumor volumes nor overall survival (P = 0.813, log-rank test), but suppressed brain invasion in a significant fraction of treated animals. A combination of 75 mg/kg cilengitide daily and irradiation (2 × 5 Gy) led to a 67% reduction of MRI-estimated tumor volumes in the intracranial model (P < 0.01), whereas the corresponding reduction reached by irradiation alone was only 55% (P < 0.05). These data show that a monotherapy with cilengitide is not likely to achieve major responses in rapidly growing malignant meningiomas, although brain invasion may be reduced because of the strong antimigratory properties of the drug. The combination with radiotherapy warrants further attention.

Update on neurooncology Annual meeting of the American Society of Clinical Oncology (ASCO) 2013

At this yearʼs American society of clinical oncology (ASCO) meeting (2013) a number of recently completed randomized Phase II and III trials regarding the treatment of high- and low-grade glioma were reported. The RTOG 0825 trial and the AVAglio trial, both double-blinded, placebo-controlled Phase III trials, addressed the benefits of bevacizumab in newly diagnosed glioblastoma (GBM) alongside to the standard of care (SOC). In the randomized Phase II GLARIUS trial, bevacizumab and irinotecan was compared to the SOC in GBM with a nonmethylated O6-Methylguanine-DNA Methyltransferase (MGMT) promoter. In the recurrent setting results from the Dutch BELOB randomized three arm phase II trial were presented: Bevacizumab alone vs. lomustine alone vs. the combination in recurrent GBM. The CENTRIC trial tested the integrin inhibitor cilengitide in newly diagnosed and MGMT promoter methylated GBM. Two trials on low-grade glioma (LGG) were presented: the single arm RTOG 0424 phase II trial for LGG with at least three risk factors and first results from the randomized phase III EORTC 22033-26033 trial, including LGG patients with one or more risk factors treated either with irradiation alone or temozolomide alone. Translational research results of these trials will be expected at a later point of time.

Combining molecular targeted agents with radiation therapy for malignant gliomas

The expansion in understanding the molecular biology that characterizes cancer cells has led to the rapid development of new agents to target important molecular pathways associated with aberrant activation or suppression of cellular signal transduction pathways involved in gliomagenesis, including epidermal growth factor receptor, vascular endothelial growth factor receptor, mammalian target of rapamycin, and integrins signaling pathways. The use of antiangiogenic agent bevacizumab, epidermal growth factor receptor tyrosine kinase inhibitors gefitinib and erlotinib, mammalian target of rapamycin inhibitors temsirolimus and everolimus, and integrin inhibitor cilengitide, in combination with radiation therapy, has been supported by encouraging preclinical data, resulting in a rapid translation into clinical trials. Currently, the majority of published clinical studies on the use of these agents in combination with radiation and cytotoxic therapies have shown only modest survival benefits at best. Tumor heterogeneity and genetic instability may, at least in part, explain the poor results observed with a single-target approach. Much remains to be learned regarding the optimal combination of targeted agents with conventional chemoradiation, including the use of multipathways-targeted therapies, the selection of patients who may benefit from combined treatments based on molecular biomarkers, and the verification of effective blockade of signaling pathways.

The integrin inhibitor cilengitide enhances the anti-glioma efficacy of vasculostatin-expressing oncolytic virus

Oncolytic viral (OV) therapy has been considered as a promising treatment modality for brain tumors. Vasculostatin, the fragment of brain-specific angiogenesis inhibitor-1, shows anti-angiogenic activity against malignant gliomas. Previously, a vasculostatin-expressing oncolytic herpes simplex virus-1, Rapid Antiangiogenesis Mediated By Oncolytic virus (RAMBO), was reported to have a potent antitumor effect. Here, we investigated the therapeutic efficacy of RAMBO and cilengitide, an integrin inhibitor, combination therapy for malignant glioma. In vitro, tube formation was significantly decreased in RAMBO and cilengitide combination treatment compared with RAMBO or cilengitide monotherapy. Moreover, combination treatment induced a synergistic suppressive effect on endothelial cell migration compared with the control virus. RAMBO, combined with cilengitide, induced synergistic cytotoxicity on glioma cells. In the caspase-8 and -9 assays, the relative absorption of U87ΔEGFR cell clusters treated with cilengitide and with RAMBO was significantly higher than that of those treated with control. In addition, the activity of caspase 3/7 was significantly increased with combination therapy. In vivo, there was a significant increase in the survival of mice treated with combination therapy compared with RAMBO or cilengitide monotherapy. These results indicate that cilengitide enhanced vasculostatin-expressing OV therapy for malignant glioma and provide a rationale for designing future clinical trials combining these two agents.

Primary glioblastoma cell lines as source for analysis of the relationship between molecular phenotype and in-vitro drug sensitivity.

e13053 Background: Glioblastoma multiforma (GBM) still has a very poor prognosis even with today’s multimodal combination therapy of resection followed by radio-chemotherapy with temozolomide. Both new molecular inhibitors and immunotherapy may represent future therapeutical tools but due to the variability of the molecular composition in individual GBM, they probably depend on better response prediction. Methods: Based on a close cooperation and logistics between surgery, pathology, laboratory researchers and animal care facilities, we established and analysed cell lines of about 30 primary brain tumors, most of them GBM. Tumors and cell lines were characterised by morphology, growth behaviour, numerous extra- and intracellular antigens, and particularly regarding molecular features. Further, tumors were established in a subcutaneous xenograft mouse model, and growth characteristics were described. These in vitro and in vivo models represent an ideal tool for response analysis of single agent or combined treatment in early cell passages in order to predict response. Besides, relevant antigens and possible shifts of antigen-presentation in tumors can be assessed. Numerous analyses using established and new antitumor compounds – e.g. the integrin inhibitor cilengitide – were performed. Results: We found that although the specific integrin expression is individually different in the tumors analysed, cilengitide sensitivity was similar in most. Addition of temozolomide led to additional, yet not over-additive cytotoxicity. In our panel of GBM specimens we found a very heterogenous pattern of molecular alterations, going along with variations of drug sensitivity. Conclusions: This indicates that, in the future field of individualized approaches, such models are required, in order to enable future strategies to predict the efficacy of immunological, small molecular, biological-based, cytotoxic or other therapeutic strategies. The project was supported by the Förderkreis für krebskranke Kinder Rostock e.V., by a Mecklenburg-Vorpommern graduate scholarship, and by a cooperation with Merck-Serono Research and Development (gift of drug).

The αVβ3/αVβ5 integrin inhibitor cilengitide augments tumor response to melphalan isolated limb perfusion in a sarcoma model

Isolated limb perfusion (ILP) with melphalan and tumor necrosis factor (TNF)-α is used to treat bulky, locally advanced melanoma and sarcoma. However, TNF toxicity suggests a need for better-tolerated drugs. Cilengitide (EMD 121974), a novel cyclic inhibitor of alpha-V integrins, has both anti-angiogenic and direct anti-tumor effects and is a possible alternative to TNF in ILP. In this study, rats bearing a hind limb soft tissue sarcoma underwent ILP using different combinations of melphalan, TNF and cilengitide in the perfusate. Further groups had intra-peritoneal (i.p.) injections of cilengitide or saline 2 hr before and 3 hr after ILP. A 77% response rate (RR) was seen in animals treated i.p. with cilengitide and perfused with melphalan plus cilengitide. The RR was 85% in animals treated i.p. with cilengitide and ILP using melphalan plus both TNF and cilengitide. Both RRs were significantly greater than those seen with melphalan or cilengitide alone. Histopathology showed that high RRs were accompanied by disruption of tumor vascular endothelium and tumor necrosis. Compared with ILP using melphalan alone, the addition of cilengitide resulted in a three to sevenfold increase in melphalan concentration in tumor but not in muscle in the perfused limb. Supportive in vitro studies indicate that cilengitide both inhibits tumor cell attachment and increases endothelial permeability. Since cilengitide has low toxicity, these data suggest the agent is a good alternative to TNF in the ILP setting.