Fares Nigim

Targeting Hypoxia-Inducible Factor 1α in a New Orthotopic Model of Glioblastoma Recapitulating the Hypoxic Tumor Microenvironment

Abstract Tissue hypoxia and necrosis represent pathophysiologic and histologic hallmarks of glioblastoma (GBM). Although hypoxia inducible factor 1&agr; (HIF-1&agr;) plays crucial roles in the malignant phenotypes of GBM, developing HIF-1&agr;-targeted agents has been hampered by the lack of a suitable preclinical model that recapitulates the complex biology of clinical GBM. We present a new GBM model, MGG123, which was established from a recurrent human GBM. Orthotopic xenografting of stem-like MGG123 cells reproducibly generated lethal tumors that were characterized by foci of palisading necrosis, hypervascularity, and robust stem cell marker expression. Perinecrotic neoplastic cells distinctively express HIF-1&agr; and are proliferative in both xenografts and the patient tissue. The xenografts contain scattered hypoxic foci that were consistently greater than 50 &mgr;m distant from blood vessels, indicating intratumoral heterogeneity of oxygenation. Hypoxia enhanced HIF-1&agr; expression in cultured MGG123 cells, which was abrogated by the HIF-1&agr; inhibitors digoxin or ouabain. In vivo, treatment of orthotopic MGG123 xenografts with digoxin decreased HIF-1&agr; expression, vascular endothelial growth factor mRNA levels, and CD34-positive vasculature within the tumors, and extended survival of mice bearing the aggressive MGG123 GBM. This preclinical tumor model faithfully recapitulates the GBM-relevant hypoxic microenvironment and stemness and is a suitable platform for studying disease biology and developing hypoxia-targeted agents.

Diagnostic Accuracy of PET, SPECT, and Arterial Spin-Labeling in Differentiating Tumor Recurrence from Necrosis in Cerebral Metastasis after Stereotactic Radiosurgery

The authors retrospectively reviewed patients treated between 2007–2010 and identified 14 patients with cerebral metastasis who had clinical or radiographic progression following stereotactic radiosurgery and were imaged with arterial spin-labeling (ASL), FDG-PET, and thallium SPECT before stereotactic biopsy. FDG-PET and ASL were equally sensitive in detecting tumor progression (83%). The specificity of ASL was superior to that of the other modalities (100%, 75%, and 50%, respectively). A combination of modalities did not augment the sensitivity, specificity, positive predictive value, or negative predictive value of ASL. BACKGROUND AND PURPOSE: Radiographic assessment of cerebral metastasis after stereotactic radiosurgery remains a major challenge in neuro-oncology. It is often difficult to distinguish tumor progression from radiation necrosis in this setting using conventional MR imaging. The objective of this study was to compare the diagnostic sensitivity and specificity of different functional imaging modalities for detecting tumor recurrence after stereotactic radiosurgery. MATERIALS AND METHODS: We retrospectively reviewed patients treated between 2007 and 2010 and identified 14 patients with cerebral metastasis who had clinical or radiographic progression following stereotactic radiosurgery and were imaged with arterial spin-labeling, FDG-PET, and thallium SPECT before stereotactic biopsy. Diagnostic accuracy, specificity, sensitivity, positive predictive value, and negative predictive value were calculated for each imaging technique by using the pathologic diagnosis as the criterion standard. RESULTS: Six patients (42%) had tumor progression, while 8 (58%) developed radiation necrosis. FDG-PET and arterial spin-labeling were equally sensitive in detecting tumor progression (83%). However, the specificity of arterial spin-labeling was superior to that of the other modalities (100%, 75%, and 50%, respectively). A combination of modalities did not augment the sensitivity, specificity, positive predictive value, or negative predictive value of arterial spin-labeling. CONCLUSIONS: In our series, arterial spin-labeling positivity was closely associated with the pathologic diagnosis of tumor progression after stereotactic radiosurgery. Validation of this finding in a large series is warranted.

Ventriculoperitoneal shunting: Laparoscopically assisted versus conventional open surgical approaches.

Objectives: Ventriculoperitoneal shunting (VPS) is a mainstay of hydrocephalus therapy, but carries a significant risk of device malfunctioning. This study aims to compare the outcomes of laparoscopic ventriculoperitoneal shunting versus open ventriculoperitoneal shunting (OVPS) VPS-placement and reviews our findings in the pertinent context of the literature from 1993 to 2012. Materials and Methods: Between 2003 and 2012, a total of 232 patients underwent first time VPS placement at Beth Israel Deaconess Medical Center. Of those, 155 were laparoscopically guided and 77 were done conventionally. We analyzed independent variables (age, gender, medical history, clinical presentation, indication for surgery and surgical technique) and dependent variables (operative time, post-operative complications, length of stay in the hospital) and occurrence of shunt failure. Results: Mean operative time was 43.7 min (18.0-102.0) in the laparoscopic group versus 63.0 min (30.0-151.0) in the open group, (P < 0.05). Length of stay was similar, 5 days in the laparoscopic and in the open group, (P = 0.945). The incidence of shunt failure during the entire follow-up period was not statistically different between the two groups, occurring in 14.1% in the laparoscopic group and 16.9% in the open group, (P = 0.601). Kaplan-Meier analysis demonstrated no difference in shunt survival between the two groups (P = 0.868), with functionality in 85% at 6-months and 78.5% at 1-year. Conclusion: According to our study, LVPS-placement results compare similarly to OVPS placement in most aspects. Since laparoscopic placement is not routinely indicated, we suggest a prospective study to assess its value as an alternate technique especially suitable in obese patients and patients with previous abdominal operations.

Oncolytic viruses on the cusp of success?: proceedings of the 9th International Conference on Oncolytic Virus Therapeutics

Boston, Massachusetts, was the site of the 9th International Conference on Oncolytic Virus Therapeutics held 13–16 June 2015. An overarching theme of the meeting was the continued development of combinatorial treatment regimens to bolster the therapeutic potential of oncolytic viruses (OVs). Several talks focused on combining OVs with immune checkpoint inhibitors in a wide array of tumors, signaling an experimental and thematic shift toward driving immune activation to clear a tumor versus relying on direct viral oncolysis. An important aspect of the meeting was the variety of ongoing OV clinical trials. Topics ranged from basic virology to clinical trials and from academic research to intellectual property and biotechnology. There was much excitement due to the US Food and Drug Administration’s recent consideration of talimogene laherparepvec (T-VEC) for the treatment of advanced melanoma (T-VEC was approved in October, following the conference). Here, we summarize the meeting’s primary themes, which reflect the current state of the field.

A new patient-derived orthotopic malignant meningioma model treated with oncolytic herpes simplex virus

BACKGROUND Higher-grade meningiomas (HGMs; World Health Organization grades II and III) pose a clinical problem due to high recurrence rates and the absence of effective therapy. Preclinical development of novel therapeutics requires a disease model that recapitulates the genotype and phenotype of patient HGM. Oncolytic herpes simplex virus (oHSV) has shown efficacy and safety in cancers in preclinical and clinical studies, but its utility for HGM has not been well characterized. METHODS Tumorsphere cultures and serial orthotopic xenografting in immunodeficient mice were used to establish a patient-derived HGM model. The model was pathologically and molecularly characterized by immunohistochemistry, western blot, and genomic DNA sequencing and compared with the patient tumor. Anti-HGM effects of oHSV G47Δ were assessed using cell viability and virus replication assays in vitro and animal survival analysis following intralesional injections of G47Δ. RESULTS We established a serially transplantable orthotopic malignant meningioma model, MN3, which was lethal within 3 months after tumorsphere implantation. MN3 xenografts exhibited the pathological hallmarks of malignant meningioma such as high Ki67 and vimentin expression. Both the patient tumor and xenografts were negative for neurofibromin 2 (merlin) and had the identical NF2 mutation. Oncolytic HSV G47Δ efficiently spread and killed MN3 cells, as well as other patient-derived HGM lines in vitro. Treatment with G47Δ significantly extended the survival of mice bearing subdural MN3 tumors. CONCLUSIONS We established a new patient-derived meningioma model that will enable the study of targeted therapeutic approaches for HGM. Based on these studies, it is reasonable to consider a clinical trial of G47Δ for HGM.

Blockade of transforming growth factor-β signaling enhances oncolytic herpes simplex virus efficacy in patient-derived recurrent glioblastoma models

Despite the current standard of multimodal management, glioblastoma (GBM) inevitably recurs and effective therapy is not available for recurrent disease. A subset of tumor cells with stem‐like properties, termed GBM stem‐like cells (GSCs), are considered to play a role in tumor relapse. Although oncolytic herpes simplex virus (oHSV) is a promising therapeutic for GBM, its efficacy against recurrent GBM is incompletely characterized. Transforming growth factor beta (TGF‐β) plays vital roles in maintaining GSC stemness and GBM pathogenesis. We hypothesized that oHSV and TGF‐β inhibitors would synergistically exert antitumor effects for recurrent GBM. Here we established a panel of patient‐derived recurrent tumor models from GBMs that relapsed after postsurgical radiation and chemotherapy, based on GSC‐enriched tumor sphere cultures. These GSCs are resistant to the standard‐of‐care temozolomide but susceptible to oHSVs G47Δ and MG18L. Inhibition of TGF‐β receptor kinase with selective targeted small molecules reduced clonogenic sphere formation in all tested recurrent GSCs. The combination of oHSV and TGF‐βR inhibitor was synergistic in killing recurrent GSCs through, in part, an inhibitor‐induced JNK‐MAPK blockade and increase in oHSV replication. In vivo, systemic treatment with TGF‐βR inhibitor greatly enhanced the antitumor effects of single intratumoral oHSV injections, resulting in cures in 60% of mice bearing orthotopic recurrent GBM. These results reveal a novel synergistic interaction of oHSV therapy and TGF‐β signaling blockade, and warrant further investigations aimed at clinical translation of this combination strategy for GBM patients.

Multidisciplinary management improves survival at 1 year after surgical treatment for non-small-cell lung cancer: a propensity score-matched study†

OBJECTIVES The management of patients affected by lung cancer requires the expertise of specialists from different disciplines. Although the advantages of multidisciplinary team discussions seem obvious, there are limited studies evaluating the influence of this approach on postoperative outcomes in non-small-cell lung cancer (NSCLC). The aim of this study is to examine the impact of a multidisciplinary approach on survival of patients undergoing surgery for NSCLC. METHODS A retrospective analysis was performed on consecutive patients who underwent surgery for NSCLC between January 2008 and December 2015. Data were compared between patients treated before the implementation of a multidisciplinary tumour board (MTB), between 2008 and 2012, and those who received treatment after the implementation of the MTB, between 2012 and 2015. Patients were matched one to one according to the discussion of the MTB and on the basis of a propensity score built using several patient characteristics. A propensity score-matched analysis was performed to compare patient outcomes. RESULTS A total of 246 patients were treated prior to the initiation of the MTB and 231 patients after the initiation of the MTB. Based on the propensity score, 2 well-matched groups of 170 patients were identified. Patients who were discussed at the MTB were noted to have better outcomes when compared with those who were not discussed at the MTB on different terms including complete staging evaluation, early tumour, node and metastasis (TNM) stages and 1-year survival rate. CONCLUSIONS Implementation of a multidisciplinary thoracic malignancy conference increased the 1-year survival rate of patients who underwent a surgical resection for NSCLC.

AS1411-Induced Growth Inhibition of Glioma Cells by Up-Regulation of p53 and Down-Regulation of Bcl-2 and Akt1 via Nucleolin.

AS1411 binds nucleolin (NCL) and is the first oligodeoxynucleotide aptamer to reach phase I and II clinical trials for the treatment of several cancers. However, the mechanisms by which AS1411 targets and kills glioma cells and tissues remain unclear. Here we report that AS1411 induces cell apoptosis and cycle arrest, and inhibits cell viability by up-regulation of p53 and down-regulation of Bcl-2 and Akt1 in human glioma cells. NCL was overexpressed in both nucleus and cytoplasm in human glioma U87, U251 and SHG44 cells compared to normal human astrocytes (NHA). AS1411 bound NCL and inhibited the proliferation of glioma cells but not NHA, which was accompanied with up-regulation of p53 and down-regulation of Bcl-2 and Akt1. Moreover, AS1411 treatment resulted in the G2/M cell cycle arrest in glioma cells, which was however abolished by overexpression of NCL. Further, AS1411 induced cell apoptosis, which was prevented by silencing of p53 and overexpression of Bcl-2. In addition, AS1411 inhibited the migration and invasion of glioma cells in an Akt1-dependent manner. Importantly, AS1411 inhibited the growth of glioma xenograft and prolonged the survival time of glioma tumor-bearing mice. These results revealed a promising treatment of glioma by oligodeoxynucleotide aptamer.

Granular cell tumor of the infundibulum: a systematic review of MR-radiography, pathology, and clinical findings

IntroductionGranular cell tumors (GCTs) of the infundibulum are rare in practice and literature, resulting in a lack of evidence-based standard of care. We present two characteristic cases from our institution and perform a systematic review of the existing literature to further elucidate the presentation of this tumor and guide management.MethodsA systematic literature search was conducted according to PRISMA guidelines, yielding 42 total individual reported GCTs suitable for evaluation. Available clinical presentation, magnetic resonance imaging (MRI) characteristics, pathology, surgical approaches, and outcomes were charted. We measured frequencies of clinical characteristics and performed an outcome comparison of open versus endoscopic surgical treatment.ResultsIn this pooled dataset, GCT incidence was higher in females than males (3:1). Clinical presentation peaked in the fourth decade with tumor-related symptoms. MRI appearance was characterized by T1 isointensity (50%) and T2 hypointensity or isointensity (52%) with gadolinium contrast enhancement (74%). Histopathology demonstrated positive staining for PAS, PAS-D, S100, CD68, and TTF1. In a simple uncontrolled analysis, patients who underwent endoscopic surgery experienced more symptom improvement (p = 0.006) and lower incidence of new diabetes insipidus postoperatively (p = 0.047) versus patients who underwent open microsurgery.ConclusionsThis first comprehensive review of GCTs of the infundibulum corroborates existing data and adds significant new MR-radiological information to the literature, notably a typical tumor appearance of T1 isointensity, T2 iso- to hypointensity, and gadolinium contrast enhancement. Future prospective studies should be conducted to validate our findings.

Emerging Medical Treatments for Meningioma in the Molecular Era

Meningiomas are the most common type of primary central nervous system tumors. Approximately, 80% of meningiomas are classified by the World Health Organization (WHO) as grade I, and 20% of these tumors are grade II and III, considered high-grade meningiomas (HGMs). Clinical control of HGMs, as well as meningiomas that relapse after surgery, and radiation therapy is difficult, and novel therapeutic approaches are necessary. However, traditional chemotherapies, interferons, hormonal therapies, and other targeted therapies have so far failed to provide clinical benefit. During the last several years, next generation sequencing has dissected the genetic heterogeneity of meningioma and enriched our knowledge about distinct oncogenic pathways driving different subtypes of meningiomas, opening up a door to new personalized targeted therapies. Molecular classification of meningioma allows a new design of clinical trials that assign patients to corresponding targeted agents based on the tumor genetic subtypes. In this review, we will shed light on emerging medical treatments of meningiomas with a particular focus on the new targets identified with genomic sequencing that have led to clinical trials testing novel compounds. Moreover, we present recent development of patient-derived preclinical models that provide platforms for assessing targeted therapies as well as strategies with novel mechanism of action such as oncolytic viruses.