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Background: TOPACIO was a phase I/II study evaluating the PARP inhibitor (PARPi) niraparib in combination with the anti-PD-1 antibody pembrolizumab in patients with locally advanced and metastatic triple-negative breast cancer (TNBC, n=55) and ovarian cancer irrespective of BRCA mutation status. In the efficacy-evaluable population (n=47) the objective response rate (ORR) was 21% and disease control rate (DCR) 49%. Although activity was greater in patients with BRCA mutations (7/15, ORR=47% and 12/15, DCR=80%), durable clinical benefit was seen in patients with wild-type BRCA tumors (3/27, ORR=11% and 9/27, DCR=33%). In a limited cohort of 20 patients with durable clinical benefit, there were 8 BRCA wildtype patients, four of whom had mutations in genes associated with the homologous recombination repair and other DNA damage repair pathways. Pre-treatment tissues were collected and evaluated for tumor PD-L1 status. Patients with PD-L1 positive tumors (28/47, 60%) had a higher response rate (9/28, ORR=32%) than those with PD-L1 negative tumors (1/13, ORR=8%; 6 tumors had unknown PD-L1 status). It remains unstudied whether the tumor’s gene expression profile or immune status in baseline biospecimens is predictive of treatment response. In this study we conducted exploratory biomarker analyses to test the hypothesis that gene expression patterns and immune status are associated with treatment response. Methods: Transcriptional profiling of baseline samples was performed using the BC360 (n=41) and PanCancer IO360 (n=42) panels (Nanostring) and multigene signatures were used to measure tumor and immune activities as well as relative immune cell abundance. Transcriptional analysis was paired with high-dimensional, single-cell cyclic immunofluorescence (CyCIF) of samples that had adequate tissue for analysis (n=19) to characterize the composition and topology of the immune microenvironment at single-cell resolution. Results: Nanostring transcriptional analysis revealed that PAM50 genes stratified tumor samples into 4 subgroups with distinct histology as determined by CyCIF. Each subgroup was capable of responding to niraparib plus pembrolizumab. Multiple genes involved in WNT signaling (WNT5B, TANKS1, TANKS2, PARP4, and NET02) were associated with favorable clinical responses. Low neuropilin and tolloid-like protein 2 (NETO2) gene expression was strongly correlated with favorable progression free survival (PFS; R=-0.61, p=0.0008, Spearman’s correlation), suggesting it may be a predictive biomarker of therapeutic response. Nanostring gene expression signatures for tumor inflammation, apoptosis, and inflammatory chemokines also distinguished responders from non-responders (p Citation Format: Jennifer L Guerriero, Gregory J Baker, Jia-Ren Lin, Yu-An Chen, Ricardo Pastorello, Tuulia Vallius, Janae Davis, Clarence Yapp, Sarah E Church, Eric Miller, Anniina Färkkilä, Shaveta Vinayak, Melinda L Telli, Giulia Fulci, Alan D'Andrea, Geoffrey I Shapiro, Sara M Tolaney, Sandro Santagata, Peter K Sorger, Elizabeth A Mittendorf. High-dimensional, single-cell analysis and transcriptional profiling reveal novel correlatives of response to PARP inhibition plus PD-1 blockade in triple-negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-07-13. more...

Background There is a critical need to identify patient characteristics associated with long-term ovarian cancer survival. Methods Quality of life (QOL), measured by the Functional Assessment of Cancer Therapy-Ovarian-Trial Outcome Index (FACT-O-TOI), including physical, functional, and ovarian-specific subscales, was compared between long-term survivors (LTS) (8+ years) and short-term survivors (STS) ( Results QOL differed statistically significantly between STS (N = 1115) and LTS (N = 260) (P Conclusions Baseline and longitudinal QOL change scores distinguished LTS vs STS and are robust prognosticators for long-term survival. Results have trial design and supportive care implications, providing meaningful prognostic value in this understudied population. more...

BT8009 is a Bicycle® Toxin Conjugate (BTC™), a novel class of chemically synthesized molecules, comprising a bicyclic peptide targeting Nectin-4 tumor antigen, linked to cytotoxin (monomethyl auristatin E [MMAE]) via a valine-citrulline (val-cit) cleavable linker. Due to their small size, BTCs represent a unique therapeutic class, combining the pharmacology normally associated with a biologic with the pharmacokinetic properties of a small molecule. Here, we describe the preliminary monotherapy dose escalation results of the ongoing multicenter Phase I/II clinical trial (NCT04561362) that assesses the safety and tolerability of BT8009 administration in patients with advanced solid tumors associated with Nectin-4 expression, not exposed to enfortumab vedotin. Patients were treated until disease progression or intolerable toxicity, with tumor assessments for response per RECIST taken every two months. Nectin-4 expression levels were measured in tumor tissue. Thirty-four patients were initiated on weekly BT8009 (7 patients at 2.5 mg/m2, 20 patients at 5.0 mg/m2, and 4 patients at 7.5 mg/m2) or biweekly BT8009 (3 patient at 7.5 mg/m2). Baseline demographics were 62% patients were male, 44% and 56% were ECOG 0 and ECOG 1, respectively, median age was 65.5 years. BT8009 exhibits linear pharmacokinetics. The most common treatment-related adverse events were nausea (14 patients, 41%; ≥ G3 1 patient, 3%), fatigue (13 patients, 38%; ≥ G3 2 patients, 6%), anorexia (11 patients, 32%; ≥ G3 0 patients), constipation (10 patients, 29%; ≥ G3 1 patient, 3%) and anemia (10 patients, 29%; ≥ G3 3 patients, 9%). To date, BT8009 had low incidences of ocular disorders (3%), hyperglycemia (6%), neuropathy (6%), and rash (18%). There was 1 dose-limiting toxicity (G3 asthenia) reported at the 7.5 mg/m2 weekly dose level. Six patients (18%) experienced an SAE, with only 1 related SAE (vomiting). Treatment-emergent AEs resulting in treatment discontinuation, dose interruption, or reductions were observed in 2 patients (6%), 11 patients (32%), and 5 patients (15%), respectively. Preliminary confirmed responses observed in patients with urothelial carcinoma (UC) enrolled in the 5 mg/m2 cohort show 4/8 patients with a complete response (CR) or partial response (PR), including 1/8 patients with a CR and 3/8 patients with a PR, and 2/8 patients (25%) with stable disease (SD), reflecting a 50% overall response rate and a 75% disease control rate in UC patients for this cohort. BT8009 exhibits a promising preliminary tolerability profile and preliminary antitumor activity. The molecule will continue to be explored in the current dose-escalation/dose-expansion study of BT8009 monotherapy and in combination with nivolumab. Citation Format: Meredith McKean, Capucine Baldini, Loic Verlingue, Bernard Doger, Gerald Falchook, Antoine Italiano, Julia Lostes, Oscar Reig, Roshawn Watson, Sebastien Hazard, Dominic Smethurst, Giulia Fulci, Hongmei Xu, Phil Jeffery, Kevin Lee, Irene Braña, Sophie Cousin, Elisa Fontana, Hendrik-Tobias Arkenau. BT8009-100 phase I/II study of novel bi-cyclic peptide and MMAE conjugate BT8009 in patients with advanced malignancies associated with nectin-4 expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT025. more...

Background We evaluated apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) as a schwannoma tumor suppressor and explored its utilization in a schwannoma gene therapy strategy that may be translated to clinical use. Methods ASC protein expression and mRNA level were assessed in human schwannoma by immunohistochemistry and quantitative PCR, respectively. Methylation- specific PCR was used to assess ASC promoter methylation. The effect of ASC overexpression in schwannoma cells was evaluated through ATP-based viability, lactate dehydrogenase release, and apoptosis staining. Western blotting and colorimetric assay were used to test the effect of ASC overexpression on endogenous pro-apoptotic pathways. Bioluminescence imaging, behavioral testing, and immunohistochemistry in human xenograft and murine allograft schwannoma models were used to examine the efficacy and toxicity of intratumoral injection of adeno-associated virus (AAV) vector encoding ASC. Results ASC expression was suppressed via promoter methylation in over 80% of the human schwannomas tested. ASC overexpression in schwannoma cells results in cell death and is associated with activation of endogenous caspase-9, caspase-3, and upregulation of BH3 interacting-domain death agonist. In a human xenograft schwannoma model, AAV1-mediated ASC delivery reduced tumor growth and resolved tumor-associated pain without detectable toxicity, and tumor control was associated with reduced Ki67 mitotic index and increased tumor-cell apoptosis. Efficacy of this schwannoma gene therapy strategy was confirmed in a murine schwannoma model. Conclusion We have identified ASC as a putative schwannoma tumor suppressor with high potential clinical utility for schwannoma gene therapy and generated a vector that treats schwannomas via a novel mechanism that does not overlap with current treatments. more...

e15066 Background: Cancer therapies that effectively cross the blood-brain barrier (BBB) to treat primary and metastatic brain tumors represent a critical unmet medical need. Brain metastasis are diagnosed in 10-40% of solid tumors and are associated with poor outcomes1. Preclinical data showed that niraparib has shown higher brain penetration as compared to other PARP inhibitors in an intact BBB setting2,3; however limited data is available to understand the penetration and residence of PARP inhibitors in a disrupted BBB setting. We conducted studies to assess the brain penetration of niraparib and olaparib in a disrupted BBB setting in an orthotopic animal tumor model. Additionally, we report tissue biodistribution of niraparib in a xenograft tumor mouse model. Methods: Brain penetration of niraparib and olaparib was assessed in GL261 orthotopic glioblastoma models. Niraparib and olaparib were dosed at 35 and 50 mg/kg once daily for 3-days, respectively. Brain tumor and contralateral normal brain region were excised following 3-day dosing. In a separate study niraparib tissue distribution in various organs was monitored in an ovarian (A2780) xenograft tumor mouse model. Several organs including tumors were excised following 5-day oral dosing of niraparib at 35mg/kg. Tissue samples were processed by homogenization followed by analysis using LC-MS/MS. Data were analyzed using non-compartmental analysis. Results: Mean drug concentrations at 2h post last dose in brain tumor region and normal contralateral brain region were 24µM and 2.15µM for niraparib compared with 0.7µM and 0.18µM for olaparib. Mean drug concentration at 24h post last dose in brain tumor region and normal contralateral region were 1.36µM and 0.53µM for niraparib compared with 0.17µM and 0.01µM for olaparib. In a A2780 xenograft tumor model tissue distribution study, niraparib demonstrated high levels of tissue penetration and retention in most perfused (lung, liver, kidney) and non-perfused tissues (tumor, ovary, pancreas). In most cases, tissues had at least 2-fold higher exposure than plasma at steady state following repeat oral dosing. Conclusions: Niraparib brain tumor tissue concentration was at least 25-fold greater than olaparib at 2h post dose. Data also suggests niraparib had better retention in brain tumor over olaparib with mean exposure as high as 1.4µM at 24h post dose (terminal phase) with just 3-days of dosing. These findings demonstrated that a favorable pharmacokinetic profile of niraparib was achieved in the disrupted BBB setting of the glioblastoma model. High penetration of niraparib in brain and other tissues along with a strong correlation with systemic exposures support the future investigation of niraparib in cancers with high incidence of brain metastasis. References: 1. Epidemiology, Biology, and Therapy; Chapter 1; 2015, Pages 3-29. 2. Oncotarget . 2018 Dec 14; 9(98): 37080–37096. 3. AACR 2019, Poster 3888. more...

Currently, there is no stable and flexible method to label and track cytotoxic T-lymphocytes (CTLs) in vivo in CTL immunotherapy. We aimed to evaluate whether the sulfo-hydroxysuccinimide (NHS)-biotin-streptavidin (SA) platform could chemically modify the cell surface of CTLs for in vivo tracking. CD8+ T lymphocytes were labeled with sulfo-NHS-biotin under different conditions and then incubated with SA-Alexa647. Labeling efficiency was proportional to sulfo-NHS-biotin concentration. CD8+ T lymphocytes could be labeled with higher efficiency with sulfo-NHS-biotin in DPBS than in RPMI (P more...

In 2019 there will be 22,500 new cases of ovarian cancer, resulting in approximately 14,000 deaths. Ovarian cancer remains the highest case fatality rate of any gynecologic cancer. Despite significant improvement in the surgical and chemotherapeutic managements of ovarian cancer patients, the overall survival has not changed in 30 years. However, these new therapies have resulted in a significant improvement in median survival, resulting in increasing numbers of patients surviving greater than 10 years with disease. The clinical and molecular features of these unique patients remain uncharacterized. The Department of Defense Ovarian Cancer Research Program (DOD OCRP) funded the creation of our interdisciplinary Long-term Survivor Consortium (LTSC), composed of 6 research sites including MDACC, UAB, IU, UCI, Ludwig Cancer Research, and University Hospitals of Canton Vaud (CHUV) and INOVA, a bioinformatic center at DFCI, and administrative centers at UCI and UAB. The purpose of the consortium is to identify characteristics and predictors of long-term survival in advanced ovarian cancer patients. The consortium is overseen by both a scientific and advocacy advisory board to guide direction and efforts. 285 specimens of advanced-stage high-grade serous ovarian cancers with full clinical annotation including greater than 12 years of follow-up were analyzed for this project. In addition, 340 early-stage high-grade ovarian cancers were available for one of the AIMs of the project. These latter samples were obtained through the creation of an international consortium funded by the DOD OCRP. All specimens were first reviewed for tumor context by H&E staining to determine percentage of tumor. The scientific platforms include whole transcriptome, microRNAs, global proteomics, immune profiling, and methylation. All specimens were analyzed on each individual platform and the results will be integrated in a global process. In parallel with these efforts, a systematic analysis of quality of life of patients at the time of diagnosis and later during the course of their disease based upon patient-reported outcome surveys has been undertaken. These data will also be integrated with genomic results to produce signatures that can further characterize long-term survivors of ovarian cancer. Citation Format: Michael J. Birrer, Lari Wenzel, Austin Miller, Heather Lankes, Nilsa Ramirez, Giovanni Parmigiani, Samuel Mok, Kenneth Nephew, Thomas Conrads, George Coukos, George L. Maxwell, Giulia Fulci, Mary Scroggins. The Long-Term Ovarian Cancer Survivor Project: A Department of Defense initiative [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr IA06. more...

Clinical trials have proven oncolytic virotherapy to be safe but not effective. We have shown that oncolytic viruses (OV) injected into intracranial gliomas established in rodents are rapidly cleared, and this is associated with up-regulation of markers (CD68 and CD163) of cells of monocytic lineage (monocytes/microglia/macrophages). However, it is unclear whether these cells directly impede intratumoral persistence of OV through phagocytosis and whether they infiltrate the tumor from the blood or the brain parenchyma. To investigate this, we depleted phagocytes with clodronate liposomes (CL) in vivo through systemic delivery and ex vivo in brain slice models with gliomas. Interestingly, systemic CL depleted over 80% of peripheral CD163+ macrophages in animal spleen and peripheral blood, thereby decreasing intratumoral infiltration of these cells, but CD68+ cells were unchanged. Intratumoral viral titers increased 5-fold. In contrast, ex vivo CL depleted only CD68+ cells from brain slices, and intratumoral viral titers increased 10-fold. These data indicate that phagocytosis by both peripheral CD163+ and brain-resident CD68+ cells infiltrating tumor directly affects viral clearance from tumor. Thus, improved therapeutic efficacy may require modulation of these innate immune cells. In support of this new therapeutic paradigm, we observed intratumoral up-regulation of CD68+ and CD163+ cells following treatment with OV in a patient with glioblastoma. [Cancer Res 2007;67(19):9398–406] more...

e17061 Background: Ovarian cancer (OC) is the fifth leading cause of cancer-related death among women in the United States. Standard treatment includes debulking surgery followed by platinum based chemotherapy. While most tumors respond to this treatment, 70% of the tumors recur and develop into a chemo-resistant disease. There is a need for new therapies targeting recurrent chemoresistant OC. To address this need, Mirvetuximab Soravtansine (ImmunoGen, Waltham, MA) has developed an antigen-drug conjugate (ADC) containing DM4, a highly potent maytansinoid derivative that induces the cell cycle arrest, conjugated to an antibody targeting folate receptor alpha (FRα). Mirvetuximab Soravtansine (IMGN853), was tested in Phase I clinical trials on women with recurrent OC and showed low grade toxicity profile and activity in platinum-resistant disease. The goal of this study is to characterize the mechanism(s) leading to IMGN853 resistance in OC and test whether anticancer drugs targeting these mechanisms could be used in combination with IMGN853 for an additive/synergistic therapeutic effect. Methods: In vitro experiments were performed to detect and modulate FRα expression. Results: We show that sensitivity of OC cell lines to IMGN853 correlates with the expression levels of FRα (R = 0.82). Long-term exposure of sensitive cells to sublethal doses of IMGN853 induces drug resistance which correlates with decreased FRα expression. Anti-cancer drugs such as dexamethasone (Dex), which induces glucocorticoid receptors, or epigenetic modulators (Trichostatin A and 5-Azacytidine) induce FRα expression in SKOV3 and OVCAR8 OC cells, suggesting the possibility to use these drugs to maintain sensitivity of OC cells to IMGN853 and increase its therapeutic window. The therapeutic benefits of combining each of these drugs with IMGN853 will be further tested in mice using ovarian cancer patients’ derived xenografts with different FRα expression levels. Conclusions: These findings have clinical implications as they indicate that OC sensitivity to IMGN853 is modulated in part by changes in FRα levels. Resistance to this drug may be overcome by simultaneous treatment with Dex or other anti-cancer drugs such as TSA or AZA. more...

The oncolytic adenovirus Delta24-RGD represents a new promising therapeutic agent for patients with a malignant glioma and is currently under investigation in clinical phase I/II trials. Earlier preclinical studies showed that Delta24-RGD is able to effectively lyse tumor cells, yielding promising results in various immune-deficient glioma models. However, the role of the immune response in oncolytic adenovirus therapy for glioma has never been explored. To this end, we assessed Delta24-RGD treatment in an immune-competent orthotopic mouse model for glioma and evaluated immune responses against tumor and virus. Delta24-RGD treatment led to long-term survival in 50% of mice and this effect was completely lost upon administration of the immunosuppressive agent dexamethasone. Delta24-RGD enhanced intra-tumoral infiltration of F4/80+ macrophages, CD4+ and CD8+ T-cells, and increased the local production of pro-inflammatory cytokines and chemokines. In treated mice, T cell responses were directed to the virus as well as to the tumor cells, which was reflected in the presence of protective immunological memory in mice that underwent tumor rechallenge. Together, these data provide evidence that the immune system plays a vital role in the therapeutic efficacy of oncolytic adenovirus therapy of glioma, and may provide angles to future improvements on Delta24-RGD therapy. more...

TP53 is the most frequently mutated gene in cancer and about 40% of glioblastoma express mutated p53 protein. The effects of many anti-cancer agents are largely dependent on p53-mediated apoptosis at the G1/S cell cycle checkpoint subsequent to DNA damage. Therefore, TP53 status may help stratifying patients into subsets that may respond differently to treatments such as chemo- and radiotherapy.1,2 Since an inverse relationship between TP53 mutation and radiosensitivity has been observed in glioblastomas,3 it has been hypothesized that inactivation of TP53 may confer resistance to radio- and possibly chemotherapeutic agents.4,5 Clearly it is important to better understand the role of physiologic responses of p53 in these processes for developing optimal therapeutic strategies for glioma patients. For studying the role of p53 in these mechanisms, wild-type (WT) p53 function was restored in various glioblastoma cell lines by several gene transfer methods, including stable transfection of p53 constructs inducible by dexamethasone6 or tetracycline,7 an exogenous murine p53 Val 135 temperature-sensitive (ts) mutant,8 p53 expression from retroviruses9 and adenoviruses.10 Expression of p53 in glioblastoma cells from stably transfected clones or retrovirally transduced genes induced growth arrest or senescence, whereas expression from adenoviruses induced apoptosis. Reversibility of the growth arrest was not determined. The reasons for these uneven responses are unclear but may be linked to variable levels of p53 expression driven by the exogenous promoters used in all these constructs, perturbation of cellular status by the large difference of culture temperature (6°C) for the exogenous ts mutant, incomplete function of murine p53 in human cells, variation in p53 responses in different cell lines and synergy of p53 action with cellular responses to viral infection. To reassess glioblastoma cell responses to restoration of WT p53 activity close to physiologic levels, we have taken advantage of our discovery of a glioblastoma cell line (LN382) expressing a p53 mutant with ts properties in yeast.11 Here we demonstrate that this endogenous p53 mutant switches from mutant to WT activity over a narrow 3°C temperature range (37–34°C) in LN382 cells, using several assays for p53 activity. Using this cell line, we have subsequently analyzed changes in cell proliferation and apoptosis in response to p53 activation in the absence of genotoxic stress. The absolute advantage of using the intrinsic ts mutant over artificially transfected TP53 genes is that because the ts mutant is under the control of endogenous TP53 gene regulatory elements its expression level is expected to be in the physiologic range. Also, the results are not influenced by the selection of a particular clone resistant to cell-cycle arrest, senescence or apoptosis induced by p53, and does not undergo counterselection of mutant p53, which occurs rapidly after transfection of WT TP53 alleles.9,12 This cell line thus will be invaluable in permitting biochemical analyses of the molecular mechanisms underlying p53 action in a variety of situations. more...

e21570Background: A consortium of multi-disciplinary investigators and patient advocates was assembled to address key questions related to outcomes of long-term (LT) survivors with ovarian cancer (... more...

Purpose: Inflammation occurs routinely when managing gliomas and is not easily distinguishable from tumor regrowth by current MRI methods. The lack of noninvasive technologies that monitor inflammation prevents us to understand whether it is beneficial or detrimental for the patient, and current therapies do not take this host response in consideration. We aim to establish whether a gadolinium (Gd)-based agent targeting the inflammatory enzyme myeloperoxidase (MPO) can selectively detect intra- and peritumoral inflammation as well as glioma response to treatment by MRI. Methods: We carried out serial Gd-bis-5-HT-DTPA (MPO-Gd) MRI before and after treating rodent gliomas with different doses of oncolytic virus (OV) and analyzed animal survival. The imaging results were compared with histopathologic and molecular analyses of the tumors for macrophage/microglia infiltration, virus persistence, and MPO levels. Results: Elevated MPO activity was observed by MRI inside the tumor and in the peritumoral cerebrum at day 1 post–OV injection, which corresponded with activation/infiltration of myeloid cells inhibiting OV intratumoral persistence. MPO activity decreased, whereas tumor size increased, as the virus and the immune cells were cleared (days 1–7 post–OV injection). A 10-fold increase in viral dose temporally decreased tumor size, but augmented MPO activity, thus preventing extension of viral intratumoral persistence. Conclusions: MPO-Gd MRI can distinguish enhancement patterns that reflect treatment-induced spatiotemporal changes of intratumoral and intracerebral inflammation from those indicating tumor and peritumoral edema. This technology improves the posttreatment diagnosis of gliomas and will increase our understanding of the role of inflammation in cancer therapy. Clin Cancer Res; 17(13); 4484–93. ©2011 AACR. more...

The tumor microenvironment is being increasingly recognized as an important determinant of tumor progression as well as of therapeutic response. We investigated oncolytic virus (OV) therapy-induced changes in tumor blood vessels and the impact of modulating tumor vasculature on the efficacy of oncolytic virus therapy.Rat glioma cells (D74/HveC) were implanted intracranially in immune-competent rats. Seven days later, the rats (groups of 3-7 rats) were treated with oncolytic virus (hrR3), and, 3 days later, brains were harvested for evaluation. Some rats were treated with angiostatic cRGD peptide 4 days before oncolytic virus treatment. Some rats were treated with cyclophosphamide (CPA), an immunosuppressant, 2 days before oncolytic virus treatment. Changes in tumor vascular perfusion were evaluated by magnetic resonance imaging of live rats and by fluorescence microscopy of tumor sections from rats perfused with Texas red-conjugated lectin immediately before euthanasia. Leukocyte infiltration in tumors was evaluated by anti-CD45 immunohistochemistry, and the presence of oncolytic virus in tumors was evaluated by viral titration. Changes in cytokine gene expression in tumors were measured by quantitative real-time polymerase chain reaction-based microarrays. Survival was analyzed by the Kaplan-Meier method. All statistical tests were two-sided.Oncolytic virus treatment of experimental rat gliomas increased tumor vascular permeability, host leukocyte infiltration into tumors, and intratumoral expression of inflammatory cytokine genes, including interferon gamma (IFN-gamma). The increase in vascular permeability was suppressed in rats pretreated with cyclophosphamide. Compared with rats treated with hrR3 alone, rats pretreated with a single dose of cRGD peptide before hrR3 treatment had reduced tumor vascular permeability, leukocyte infiltration, and IFN-gamma protein levels (mean IFN-gamma level for hrR3 versus hrR3 + cRGD = 203 versus 65.6 microg/mg, difference = 137 microg/mg, 95% confidence interval = 72.7 to 202.9 microg/mg, P = .006); increased viral titers in tumor tissue; and longer median survival (21 days versus 17 days, P.001).A single dose of angiostatic cRGD peptide treatment before oncolytic virus treatment enhanced the antitumor efficacy of oncolytic virus. more...

Oncolytic viruses are genetically altered replication-competent viruses that infect, and reproduce in, cancer cells but do not harm normal cells. On lysis of the infected cells, the newly formed viruses burst out and infect other tumor cells. Experiments with injecting mutant herpes simplex virus 1 (hrR3) into glioma implanted in brains of rats show lack of efficacy in eradicating the cancer. This failure is attributed to interference by the immune system. Initial pretreatment with immunosuppressive agent cyclophosphamide reduces the percentage of immune cells. We introduce a mathematical model and use it to determine how different protocols of cyclophosphamide treatment and how increased burst size of the mutated virus will affect the growth of the cancer. One of our conclusions is that the diameter of the cancer will decrease from 4 mm to eventually 1 mm if the burst size of the virus is triple that which is currently available. The effect of repeated cyclophosphamide treatment is to maintain a low density of uninfected cells in the tumor, thus reducing the probability of migration of tumor cells to other locations in the brain. (Cancer Res 2006; 66(4): 2314-9) more...

Malignant gliomas remain amongst the most difficult cancer to treat. Viral-based gene therapies have been employed for the last decade in preclinical and clinical modes as a novel treatment modality. In this review, such therapies are summarized. The overwhelming majority of clinical studies point one to conclude that methodologies that will increase tumor infection/transduction will lead to enhanced therapeutic results. more...

In spite of significant advances in the understanding of molecular processes in tumor biology that have led to the development of oncologic therapeutic strategies, the prognosis for several types of tumors (such as brain, pancreas, or hepatic malignancies) remains dismal. Without question, a strong need exists for continued investigations in new agents and new therapeutic regimens. The realization that several genes used by viruses in their lytic life cycle interact and/or complement the function of genes employed by cells in cellular events linked to cell cycle progression, apoptosis, and/or metabolism immediately suggests the development of treatment strategies wherein viral mutants could be employed as selective anticancer agents. Such viruses (designated as oncolytic viruses) can selectively grow in tumor cells, produce viral progeny in those cells, lyse them and release this progeny that can then infect additional cells in the tumor mass. A theoretical advantage of oncolytic viruses (OV) is that their numbers should augment within the tumor mass, a property that is lacking with drugs or radiation treatments. Additionally, Ovs' mode of tumor killing differs from standard anticancer agents, providing the possibility for synergistic interactions in multimodal tumor therapies. In this review, we will describe the development of OVs and briefly review the life cycle of their wild-type (wt) counterparts. We will also summarize published results from OV clinical trials and attempt to provide a perspective on research in this area. more...

Oncolytic viruses selectively lyse tumor cells, making these agents a promising treatment modality for glioma. Accumulating data suggest that the immune system plays an important role in the anti-glioma activity of oncolytic viruses. In an immune competent glioma model, the therapeutic effect of the oncolytic adenovirus Delta24-RGD was found to depend primarily on antitumor immune responses. more...

Background: Bevacizumab (Avastin), a monoclonal antibody that inactivates VEGF, was approved by US Food and Drug Administration as a single agent for treatment of recurrent glioblastomas (GBM). It prolongs progression-free survival and controls peritumoral edema. However, its effect on prognosis and overall survival remains to be determined. Angiostatin is a naturally occurring inhibitor of angiogenesis that was shown to inhibit growth of primary and metastatic tumors, but can not be delivered efficiently to GBM. Oncolytic viruses (OV) are promising agents for the treatment of GBM, whose therapeutic potential is not fully exploited due to infiltration of anti-viral macrophages. Treatment with anti-angiogenic factors was shown to increase replication and therapeutic capacity of OV. We hypothesized that combination of Avastin with an HSV OV (G47Δ) coding for angiostatin (G47Δ-angio) would enhance GBM treatment due to increased viral spread and delivery of angiostatin. Materials & Methods: G47Δ-angio was constructed using the “flip-flop” HSV-BAC system. Expression of angiostatin was confirmed by western blot; in vitro matrigel endothelial tube formation assay was performed to test its anti-angiogenic potential. We confirmed the capacity of this virus to infect cancer cells and inhibit tumor angiogenesis in vivo, and determined therapeutic efficacy using both a subcutaneous and an intracerebral glioma model in mice. A control virus not carrying the angiostatin gene (G47Δ-empty) served as the negative control for all experiments. Avastin (5mg/kg) was delivered by i.v injection in intracerebral glioma model, started at Day 5 and followed by twice a week for consecutive 4 weeks. Tumor angiogenesis was determined by CD31 and VEGF staining, macrophages infiltration was detected by F4/80 staining. The overall survival of intracerebral glioma mice was followed up in G47Δ-angio, Avastin and combination (G47Δ-angio + Avastin) treatments. Results: G47Δ-angio decreased endothelial tube formation in vitro and demonstrated potent antiangiogenic effects in vivo. In our subcutaneous tumor model, G47Δ inhibited tumor growth (n=7/group, P Conclusion: Our results demonstrate that G47Δ-angio could significantly enhance antitumor and antiangiogenic efficacy. Moreover, the combination treatment could further improve the antitumor and antiangiogenic efficacy in intracerebral glioma model in vivo. Hence, “Arming” HSV with an antiangiogenic gene that targets both the tumor cells and tumor vasculature is a promising therapy for use with Avastin treatment in clinical translation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2568. doi:10.1158/1538-7445.AM2011-2568 more...