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Concurrent PD-1 blockade and thoracic radiotherapy is being investigated in clinical trials for locally advanced, non–small cell lung cancer and small cell lung cancer, despite a potential overlapping risk of cardiotoxicity. Our prior studies demonstrate that cardiotoxicity from concurrent cardiac irradiation and anti–PD-1 administration in a mouse model is CD8+ T-cell dependent. The objective of this study was to determine whether humoral immunity contributed to the observed cardiac tissue damage, as measured by creatine kinase MB and cardiac troponin 1 release and decline in cardiac function. In the current study, we demonstrate the presence of cardiac autoantibodies, which were essential for the occurrence of cardiotoxicity from the combined therapy. Mice subjected to cardiac irradiation, while being treated with anti–PD-1, developed high levels of antibodies that reacted with cardiac tissues in vivo and cardiac antigens in vitro. Moreover, mice deficient in B cells were protected against cardiotoxicity, whereas the transfer of autoantibody-containing sera from mice that had received combined treatment reproduced the same pathologic phenotype in mice exposed to cardiac irradiation but was not observed in normal recipients. The cardiotoxic effect of the sera, which associated with CD8+ T-cell accumulation in cardiac tissue, was limited by IgG depletion. In conclusion, concurrent cardiac irradiation and PD-1 blockade leads to production of cardiac autoantibodies, likely due to antigen exposure within the irradiated cardiac tissues, which play a key role in the resulting cardiotoxicity.

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Concurrent PD-1 blockade and thoracic radiotherapy is being investigated in clinical trials for locally advanced, non–small cell lung cancer and small cell lung cancer, despite a potential overlapping risk of cardiotoxicity. Our prior studies demonstrate that cardiotoxicity from concurrent cardiac irradiation and anti–PD-1 administration in a mouse model is CD8+ T-cell dependent. The objective of this study was to determine whether humoral immunity contributed to the observed cardiac tissue damage, as measured by creatine kinase MB and cardiac troponin 1 release and decline in cardiac function. In the current study, we demonstrate the presence of cardiac autoantibodies, which were essential for the occurrence of cardiotoxicity from the combined therapy. Mice subjected to cardiac irradiation, while being treated with anti–PD-1, developed high levels of antibodies that reacted with cardiac tissues in vivo and cardiac antigens in vitro. Moreover, mice deficient in B cells were protected against cardiotoxicity, whereas the transfer of autoantibody-containing sera from mice that had received combined treatment reproduced the same pathologic phenotype in mice exposed to cardiac irradiation but was not observed in normal recipients. The cardiotoxic effect of the sera, which associated with CD8+ T-cell accumulation in cardiac tissue, was limited by IgG depletion. In conclusion, concurrent cardiac irradiation and PD-1 blockade leads to production of cardiac autoantibodies, likely due to antigen exposure within the irradiated cardiac tissues, which play a key role in the resulting cardiotoxicity.

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PDF - 72K, Expression of monocyte phenotype markers and IL-10 in malignant gliomas.

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PDF - 69K, Gene-specific primers and probes for QRT-PCR.

PDF - 102K, Assessment of the expression of mRNAs specific for the Treg marker FoxP3 and CMV IL-10 in glioma tissues and epilepsy specimens.

Purpose:Despite standard of care (SOC) established by Stupp, glioblastoma remains a uniformly poor prognosis. We evaluated IGV-001, which combines autologous glioblastoma tumor cells and an antisense oligonucleotide against IGF type 1 receptor (IMV-001), in newly diagnosed glioblastoma.Patients and Methods:This open-label protocol was approved by the Institutional Review Board at Thomas Jefferson University. Tumor cells collected during resection were treated ex vivo with IMV-001, encapsulated in biodiffusion chambers with additional IMV-001, irradiated, then implanted in abdominal acceptor sites. Patients were randomized to four exposure levels, and SOC was initiated 4–6 weeks later. On the basis of clinical improvements, randomization was halted after patient 23, and subsequent patients received only the highest exposure. Safety and tumor progression were primary and secondary objectives, respectively. Time-to-event outcomes were compared with the SOC arms of published studies.Results:Thirty-three patients were enrolled, and median follow-up was 3.1 years. Six patients had adverse events (grade ≤3) possibly related to IGV-001. Median progression-free survival (PFS) was 9.8 months in the intent-to-treat population (vs. SOC, 6.5 months; P = 0.0003). In IGV-001–treated patients who met Stupp-eligible criteria, PFS was 11.6 months overall (n = 22; P = 0.001) and 17.1 months at the highest exposure (n = 10; P = 0.0025). The greatest overall survival was observed in Stupp-eligible patients receiving the highest exposure (median, 38.2 months; P = 0.044). Stupp-eligible patients with methylated O6-methylguanine–DNA methyltransferase promoter (n = 10) demonstrated median PFS of 38.4 months (P = 0.0008). Evidence of immune activation was noted.Conclusions:IGV-001 was well tolerated, PFS compared favorably with SOC, and evidence suggested an immune-mediated mechanism (ClinicalTrials.gov: NCT02507583).

PDF - 66K, Co-staining of GBM specimens for the astrocyte/glioma cell marker GFAP and IL-10.

PDF - 47K, Heat map representation of the expression of select genes associated with M1-M2 monocyte polarization.

Purpose: This study is directed at identifying the cell source(s) of immunomodulatory cytokines in high-grade gliomas and establishing whether the analysis of associated markers has implications for tumor grading.Experimental Design: Glioma specimens classified as WHO grade II–IV by histopathology were assessed by gene expression analysis and immunohistochemistry to identify the cells producing interleukin (IL)-10, which was confirmed by flow cytometry and factor secretion in culture. Finally, principal component analysis (PCA) and mixture discriminant analysis (MDA) were used to investigate associations between expressed genes and glioma grade.Results: The principle source of glioma-associated IL-10 is a cell type that bears phenotype markers consistent with M2 monocytes but does not express all M2-associated genes. Measures of expression of the M2 cell markers CD14, CD68, CD163, and CD204, which are elevated in high-grade gliomas, and the neutrophil/myeloid-derived suppressor cell (MDSC) subset marker CD15, which is reduced, provide the best index of glioma grade.Conclusions: Grade II and IV astrocytomas can be clearly differentiated on the basis of the expression of certain M2 markers in tumor tissues, whereas grade III astrocytomas exhibit a range of expression between the lower and higher grade specimens. The content of CD163+ cells distinguishes grade III astrocytoma subsets with different prognosis. Clin Cancer Res; 19(14); 3776–86. ©2013 AACR.

Determination of severity for adverse events

PDF - 45K, Summary of clinical characteristics from archived tissues analyzed

PDF - 73K, Correlation between expression levels of IL-10, TGF-beta1, TGF-beta2 and GBM-assorted genes in primary GBM tissues.

Pan-Cancer Immunity Panel for advanced analysis of T cell activation scores

Purpose: Despite standard of care (SOC) established by Stupp, glioblastoma remains a uniformly poor prognosis. We evaluated IGV-001, which combines autologous glioblastoma tumor cells and an antisense oligonucleotide against IGF type 1 receptor (IMV-001), in newly diagnosed glioblastoma. Patients and Methods: This open-label protocol was approved by the Institutional Review Board at Thomas Jefferson University. Tumor cells collected during resection were treated ex vivo with IMV-001, encapsulated in biodiffusion chambers with additional IMV-001, irradiated, then implanted in abdominal acceptor sites. Patients were randomized to four exposure levels, and SOC was initiated 4–6 weeks later. On the basis of clinical improvements, randomization was halted after patient 23, and subsequent patients received only the highest exposure. Safety and tumor progression were primary and secondary objectives, respectively. Time-to-event outcomes were compared with the SOC arms of published studies. Results: Thirty-three patients were enrolled, and median follow-up was 3.1 years. Six patients had adverse events (grade ≤3) possibly related to IGV-001. Median progression-free survival (PFS) was 9.8 months in the intent-to-treat population (vs. SOC, 6.5 months; P = 0.0003). In IGV-001–treated patients who met Stupp-eligible criteria, PFS was 11.6 months overall (n = 22; P = 0.001) and 17.1 months at the highest exposure (n = 10; P = 0.0025). The greatest overall survival was observed in Stupp-eligible patients receiving the highest exposure (median, 38.2 months; P = 0.044). Stupp-eligible patients with methylated O6-methylguanine–DNA methyltransferase promoter (n = 10) demonstrated median PFS of 38.4 months (P = 0.0008). Evidence of immune activation was noted. Conclusions: IGV-001 was well tolerated, PFS compared favorably with SOC, and evidence suggested an immune-mediated mechanism (ClinicalTrials.gov: NCT02507583).

Immune memory cells residing in previously infected, nonlymphoid tissues play a role in immune surveillance. In the event that circulating antibodies fail to prevent virus spread to the tissues in a secondary infection, these memory cells provide an essential defense against tissue reinfection. CNS tissues are isolated from circulating immune cells and antibodies by the blood–brain barrier, making the presence of tissue-resident immune memory cells particularly needed to combat recurrent infection by neurotropic viruses. Wild-type and laboratory-engineered rabies viruses are neurotropic, differ in pathogenicity, and have varying effects on BBB functions. These viruses have proven invaluable tools in demonstrating the importance of tissue-resident immune memory cells in the reinfection of CNS tissues. Only Type 1 immune memory is effective at therapeutically clearing a secondary infection with wild-type rabies viruses from the CNS and does so despite the maintenance of blood–brain barrier integrity.

The sphenopalatine ganglion (SPG) is a vasoactive mediator of the anterior intracranial circulation in mammals. SPG stimulation has been demonstrated to alter blood-brain barrier (BBB) permeability, although this phenomenon is not well characterized.To determine the effect of SPG stimulation on the BBB using rat models.Extravasation of fluorescent tracer 70 kDa FITC-dextran into rat brain specimens was measured across a range of stimulation parameters to assess BBB permeability. Tight junction (TJ) morphology was compared by assessing differences in the staining of proteins occludin and ZO-1 and analyzing ultrastructural changes on transmission electron microscopy (TEM) between stimulated and unstimulated specimens.SPG stimulation at 10 Hz maximally increased BBB permeability, exhibiting a 6-fold increase in fluorescent traceruptake (1.66% vs 0.28%, p 0.0001). This effect was reversed 4-hours after stimulation (0.36% uptake, p = 0.99). High-frequency stimulation at 20 Hz and 200 Hz did not increase tracer extravasation, (0.26% and 0.28% uptake, p = 0.999 and p = 0.998, respectively). Stimulation was associated a significant decrease in the colocalization of occludin and ZO-1 with endothelial markers in stimulated brains compared to control (74.6% vs. 39.7% and 67.2% vs. 60.4% colocalization, respectively, p 0.0001), and ultrastructural changes in TJ morphology associated with increased BBB permeability were observed on TEM.This study is the first to show a reversible, frequency-dependent increase in BBB permeability with SPG stimulation and introduces a putative mechanism of action through TJ disruption. Bypassing the BBB with SPG stimulation could enable new paradigms in delivering therapeutics to the CNS. Further study of this technology is needed.

The difficulty in treatment of glioblastoma is a consequence of its natural infiltrative growth and the existence of a population of therapy-resistant glioma cells that contribute to growth and recurrence. To identify cells more likely to have these properties, we examined the expression in tumor specimens of several protein markers important for glioma progression including the intermediate filament protein, Nestin (NES), a glucose transporter (Glut1/SLC2A1), the glial lineage marker, glial fibrillary acidic protein, and the proliferative indicator, Ki-67. We also examined the expression of von Willebrand factor, a marker for endothelial cells as well as the macrophage/myeloid markers CD163 and CD15. Using a multicolor immunofluorescence and hematoxylin and eosin staining approach with archival formalin-fixed, paraffin embedded tissue from primary, recurrent, and autopsy IDH1 wildtype specimens combined with high-resolution tissue image analysis, we have identified highly proliferative NES(+)/Glut1(-) cells that are preferentially perivascular. In contrast, Glut1(+)/NES(-) cells are distant from blood vessels, show low proliferation, and are preferentially located at the borders of pseudopalisading necrosis. We hypothesize that Glut1(+)/NES(-) cells would be naturally resistant to conventional chemotherapy and radiation due to their low proliferative capacity and may act as a reservoir for tumor recurrence.

Patients with grade III anaplastic astrocytomas (AA) separate into survival cohorts based on the presence or absence of mutations in isocitrate dehydrogenase (IDH). Progression to glioblastoma (GBM), morphologically distinguishable by elevated microvascular proliferation, necrosis, and cell division in tumor tissues, is considerably more rapid in IDH wild-type tumors such that their diagnosis as AA is relatively rare. More often initially presenting as GBM, these contain higher numbers of tumor-associated macrophages (TAMs) than most AA, and GBM patients also have higher levels of circulating M2 monocytes. TAM and M2 monocytes share functional properties inhibitory for antitumor immunity. Yet, although there is a wealth of data implicating TAM in tumor-immune evasion, there has been limited analysis of the impact of the circulating M2 monocytes. In the current study, immune parameters in sera, circulating cells, and tumor tissues from patients with primary gliomas morphologically diagnosed as AA were assessed. Profound differences in serum cytokines, glioma extracellular vesicle cross-reactive Abs, and gene expression by circulating cells identified two distinct patient cohorts. Evidence of type 2–immune bias was most often seen in patients with IDH wild-type AA, whereas a type 1 bias was common in patients with tumors expressing the IDH1R132H mutation. Nevertheless, a patient’s immune profile was better correlated with the extent of tumor vascular enhancement on magnetic resonance imaging than IDH mutational status. Regardless of IDH genotype, AA progression appears to be associated with a switch in systemic immune bias from type 1 to type 2 and the loss of tumor vasculature integrity.

Rabies, caused by rabies virus (RABV), is a fatal encephalitis in humans and other mammals, which continues to present a public health threat in most parts of the world. Our previous study demonstrated that Toll-like receptor 7 (TLR7) is essential in the induction of anti-RABV antibodies via the facilitation of germinal center formation. In the present study, we investigated the role of TLR7 in the pathogenicity of RABV in a mouse model. Using isolated plasmacytoid dendritic cells (pDCs), we demonstrated that TLR7 is an innate recognition receptor for RABV. When RABV invaded from the periphery, TLR7 detected viral single-stranded RNA and triggered immune responses that limited the virus’s entry into the central nervous system (CNS). When RABV had invaded the CNS, its detection by TLR7 led to the production of cytokines and chemokines and an increase the permeability of the blood-brain barrier. Consequently, peripheral immune cells, including pDCs, macrophages, neutrophils, and B cells infiltrated the CNS. While this immune response, triggered by TLR7, helped to clear viruses, it also increased neuroinflammation and caused immunopathology in the mouse brain. Our results demonstrate that TLR7 is an innate recognition receptor for RABV, which restricts RABV invasion into the CNS in the early stage of viral infection but also contributes to immunopathology by inducing neuroinflammation. IMPORTANCE Developing targeted treatment for RABV requires understanding the innate immune response to the virus because early virus clearance is essential for preventing the fatality when the infection has progressed to the CNS. Previous studies have revealed that TLR7 is involved in the immune response to RABV. Here, we establish that TLR7 recognizes RABV and facilitates the production of some interferon-stimulated genes. We also demonstrated that when RABV invades into the CNS, TLR7 enhances the production of inflammatory cytokines which contribute to immunopathology in the mouse brain. Taken together, our findings suggest that treatments for RABV must consider the balance between the beneficial and harmful effects of TLR7-triggered immune responses.

A recent study by Genschmer et al. (Cell 2019;176:113–126) presents provocative new evidence that extracellular vesicles/exosomes released by activated neutrophils can degrade extracellular proteins. Elastase that is produced by neutrophils both coats the exosomes and is protected by the exosomes from inactivation by α1 antitrypsin, ultimately causing the pathological degradation of extracellular protein fibrils in lung alveoli.

9051 Background: Patients (pts) with resectable stage IB (≥4cm)-IIIA non-small-cell lung cancer (NSCLC) derive modest overall survival benefit with neoadjuvant or postoperative adjuvant chemotherapy. Neoadjuvant therapy can speed the discovery of promising regimens by using pathologic response as a surrogate for OS. Major pathologic response (MPR), defined as < 10% viable tumor, was strongly associated with improved OS. PD-(L)1 checkpoint inhibitors in combination with chemotherapy are standard of care in advanced NSCLC. We hypothesize that the addition of N to neoadjuvant CP or CG will increase the MPR rate compared to historical controls. Methods: This is an investigator-initiated trial for pts with newly diagnosed AJCC 8th stage IB (≥4cm)-IIIA squamous or non-squamous EGFR/ALK WT NSCLC with a plan to have surgery. Pts receive 3 courses of N 360mg IV q 3w added to C 75mg/m2 IV q 3w plus P 500 mg/m2 IV q 3wks or G 1250mg/m2 IV d1, d8 with surgery 3 wks after the last dose. The primary objective is MPR. To estimate pathologic response, the resected pathology specimens are cut >1 section/cm. Using the Aperio Digital scanning system©, slides were imaged, and then annotated by at least 2 pathologists for viable tumor vs. treatment effect with respective areas then automatically calculated and percentage of viable tumor calculated. Our primary endpoint will be reached if 10/34 (29%) planned pts have at least an MPR. Results: From 6/2018-8/2019, 13 pts were enrolled all of whom had surgery. Median age was 69 (49-80), 38% women, 31% nonsquamous, 54% stage IIIA, and 77% PD-L1 positive (≥1%, SP263). Pre-surgical grade 3 toxicity occurred in 2/13 pts, one of whom was changed to carboplatin for courses 2 and 3. Grade 3 toxicities were neutropenia (2/13), anemia (1/13), and renal (1/13). One pt. developed hypothyroidism 4 mos after surgery. One pt died 6 weeks after surgery from complications unrelated to study drugs. Our primary endpoint was met; 11/13 (85%), had at least an MPR with 6/13 (46%) and 5/13 (38%) having an MPR and pCR respectively. Radiologic response rate was 46% (PR 5, CR 1). Pts with either PD-L1+ or PD-L1- had MPRs. With a median follow-up of 10 months there are no recurrences. Conclusions: The combination of nivolumab added to platinum doublets was well tolerated. The primary endpoint of MPR in at least 10/34 pts was surpassed with MPR or pCR in 11/13 pts post-surgery. MPR was seen independent of PD-L1 score. Exploratory outcomes assessing markers of immune bias in tumor tissue and plasma are in process. Clinical trial information: NCT03366766.

Introduction: We present a novel autologous cell vaccine therapy designed to treat patients with newly diagnosed glioblastoma (Trial Registration: IND 14379, NCT01550523). Methods: This phase 1b trial has a phase 2 design with 4 randomized vaccine dose cohorts in 33 patients with the objective being safety assessment but also including clinical, radiographic, and immune analyses. Eligibility criteria included age > 18 and Karnofsky score of > 60; neither bihemispheric disease nor extent of resection were exclusion criteria but autoimmune diseases were. During craniotomy for tumor resection, if frozen section confirmed GBM, incisions were made in the lower abdomen through the rectus sheath and pockets created between the sheath and the muscle and the wounds closed with a temporary three-layer closure. Tumor resection involved an aspirator that collected morselized viable tumor tissue in sterile traps. The tissue was processed by overnight culture with 0.2 mg of an IGF-1R antisense oligodeoxynucleotide/gm. The next (first postoperative) day, treated tumor cells were harvested, encapsulated in either ten or twenty small biodiffusion chambers along with 4 micrograms of the IGF-1R antisense, irradiated and then implanted at bedside in the abdominal acceptor sites as previously described (1). Chambers were explanted 24 or 48 hours later, depending on randomization. Standard of care according to Stupp (2) was initiated at 6 weeks. Studies included 3T MRI imaging and analysis of serial blood samples for T cell function and cytokine levels. Disease progression was assessed using RANO (3) and iRANO (4) criteria with a data cutoff of March 1 (N=30) used for this analysis. Results: The trial opened September 1, 2015 and completed accrual on March 1, 2018. A midpoint interim analysis revealed significantly more robust cytokine responses at the highest vaccine dose. Randomization was therefore stopped at subject 23 and amended to treat using only the highest dose. Progression-free survival (PFS) was compared to three historic SOC comparators (Stupp [2], Kong [5], and an antecedent cohort of 37 consecutive patients treated with SOC at our institution [TJUH]). PFS was significantly improved at 10.5 mo v. SOC comparators: 6.9 mo (Stupp, p = .003), 5.3 mo (Kong, p = .002) and 7 mo (TJUH, p = .013). Seventy-five percent of the 14 patients in the highest-dose cohort had robust proinflammatory and early evidence of sustained immune reactivity associated with tumor regression or no recurrence after surgery. Conclusion: These data reflect a therapeutic benefit defined as significant improvement in PFS without increased safety risk compared to three different SOC cohorts. Since GBM remains one of the most challenging solid tumors, this treatment design invites investigator collaboration in a multicenter phase 2 trial. References: 1. Andrew et al. J Clin Oncol 19:2189-2200; 2. Stupp et al. NEJM 352:987-96; 3. Wen et al. J Clin. Oncol 28:1963-72; 4. Okada et al. Lancet Oncol 16:534-42; 5. Kong et al. Oncotarget 8:7003-13. Citation Format: Kevin D. Judy, David W. Andrews, Larry Harshyne, Lawrence Kenyon, Kiran Talekar, Kofi-Buaku Atsina, Lyndon Kim, Wenyin Shi, Maria Werner-Wasik, Rhonda Kean, Samantha Garcia, Kara Pigott, Charles B. Scott, D. Craig Hooper. Phase 1b/2 prospective randomized trial of four autologous cell vaccine dose cohorts for initial treatment of glioblastoma [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B71.

We describe here a novel process for the production by glioma cells of cell-free, tumor-specific antigens that supplant the need for intact tumor cells in the induction of immunity against autologous tumor antigen. Radiation is thought to trigger the release of potentially immunostimulatory tumor antigens. However, a variety of tumor cells, including human glioblastoma multiforme (GBM) and mouse GL261 glioma cells, express high levels of insulin-like growth factor-1 receptor (IGF-1R), which has been associated with radioresistance. To determine if the combination of targeting IGF-1R with an antisense oligodeoxynucleotide (AS) and radiation causes the release of glioma antigens, we encapsulated GL261 cells in biodiffusion chambers with different doses of IGF-1R AS, subjected the chambers to 5Gy radiation, and cultured the chambers for approximately 18 hours. Bone marrow-derived dendritic cells (BMDCs) from naive mice were pulsed with the cell-free chamber contents and cultured with CD4 T cells from mice protected against the growth of GL261 cells implanted in the cerebral cortex by immunization with a GL261 cell-based vaccine. The numbers of T cells producing IFNγ in an ELISPOT assay were used as an index of antigen recognition. The contents of chambers that were incubated with viable GL261 or were irradiated but cultured without IGF-1R AS stimulated only weak T-cell responses. Substantial T-cell reactivity was only seen with BMDCs pulsed with the cell-free contents of irradiated chambers containing GL261 cells and IGF-1R AS. Overnight treatment of GL261 cells with IGF-1R AS prior to encapsulation and irradiation also promoted antigen release but was most effective only when a small amount of IGF-1R AS was also added to the chambers. Fully formulated chambers contained tumor tissues that had been cultured overnight with the IGF1-R antisense, encapsulated with additional antisense and irradiated. Chambers were incubated in PBS or implanted in the flanks of naive C57BL/6 mice overnight, then contents were retrieved and used to pulse naive BMDCs. CD4 T cells recovered from GL261-immune C57BL/6 mice were used to detect tumor antigenic determinants presented by the BMDCs with the readout being the number of cells producing IFNγ. We conclude that the treatment of IGF-1R-positive glioma cells with IGF-1R AS and sublethal irradiation stimulates the cells to release antigens capable of stimulating the IFNγ-producing CD4 Th1 cells that have been associated with therapeutic immunity against glioma cells in the GL261 model. When performed in a biodiffusion chamber, this process leads to the accumulation of immunostimulatory antigens in the absence of tumor cell products known to have inhibitory properties for Th1 cells. Immunization via the implantation of irradiated biodiffusion chambers containing autologous tumor cells recovered at surgery and IGF-1R AS is currently under investigation in a clinical trial for patients with GBM (IND 14379; ClinicalTrials.gov, NCT01550523). Citation Format: Samantha Garcia, Rhonda Kean, Aurore Lebrun, Emily Bongiorno, David W. Andrews, D. Craig Hooper. Treatment of glioma cells with IGF-1R antisense and irradiation induces the production of antigens that stimulate IFNγ production by tumor-specific CD4 T cells [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B86.

Rabies virus is a neurotropic lyssavirus which is 100% fatal in its pathogenic form when reaching unprotected CNS tissues. Death can be prevented by mechanisms delivering appropriate immune effectors across the blood-brain barrier which normally remains intact during pathogenic rabies virus infection. One therapeutic approach is to superinfect CNS tissues with attenuated rabies virus which induces blood-brain barrier permeability and immune cell entry. Current thinking is that peripheral rabies immunization is sufficient to protect against a challenge with pathogenic rabies virus. While this is undoubtedly the case if the virus is confined to the periphery, what happens if the virus reaches the CNS is less well-understood. In the current study, we find that peripheral immunization does not fully protect mice long-term against an intranasal challenge with pathogenic rabies virus. Protection is significantly better in mice that have cleared attenuated virus from the CNS and is associated with a more robust CNS recall response evidently due to the presence in CNS tissues of elevated numbers of lymphocytes phenotypically resembling long-term resident immune cells. Adoptive transfer of cells from rabies-immune mice fails to protect against CNS challenge with pathogenic rabies virus further supporting the concept that long-term resident immune cell populations must be established in brain tissues to protect against a subsequent CNS challenge with pathogenic rabies virus.

Therapeutic approaches aimed at curing prostate cancer are only partially successful given the occurrence of highly metastatic resistant phenotypes that frequently develop in response to therapies. Recently, we have described α(v)β(6), a surface receptor of the integrin family as a novel therapeutic target for prostate cancer; this epithelial-specific molecule is an ideal target since, unlike other integrins, it is found in different types of cancer but not in normal tissues. We describe a novel α(v)β(6)-mediated signaling pathway that has profound effects on the microenvironment. We show that α(v)β(6) is transferred from cancer cells to monocytes, including β(6)-/- monocytes, by exosomes and that monocytes from prostate cancer patients, but not from healthy volunteers, express α(v)β(6). Cancer cell exosomes, purified via density gradients, promote M2 polarization, whereas α(v)β(6) down-regulation in exosomes inhibits M2 polarization in recipient monocytes. Also, as evaluated by our proteomic analysis, α(v)β(6) down-regulation causes a significant increase in donor cancer cells, and their exosomes, of two molecules that have a tumor suppressive role, STAT1 and MX1/2. Finally, using the Pten(pc-/-) prostate cancer mouse model, which carries a prostate epithelial-specific Pten deletion, we demonstrate that α(v)β(6) inhibition in vivo causes up-regulation of STAT1 in cancer cells. Our results provide evidence of a novel mechanism that regulates M2 polarization and prostate cancer progression through transfer of α(v)β(6) from cancer cells to monocytes through exosomes.

Glioblastoma (GBM), the most aggressive primary brain malignancy, consists of diverse cell subpopulations expressing a variety of cell lineage markers. Improvements in GBM therapy and survival require a deeper knowledge of the shifting subpopulations of tumorigenic cells within typical GBMs and their relative vulnerabilities. GBM development is associated with the appearance of highly proliferative tumor cells that lead to a hypoxic, metabolically reprogrammed, immunosuppressive microenvironment that favors tumor progression. In addition, GBM contains self-renewing, tumorigenic cancer stem cells (CSC) that contribute to tumor initiation and therapeutic resistance. Using a combined multicolor immunofluorescent and Hematoxylin and Eosin (H&E) staining approach with archival formalin-fixed, paraffin embedded tissue from primary, recurrent, and autopsy glioblastoma specimens, we have investigated the complex topology of the GBM microenvironment with particular focus on the association and distribution of several important functional and metabolic markers. High-resolution tissue image analysis permitted precise colocalization and quantification of four biomarkers (Ki-67, GLUT1, Nestin, Hif-1a) of the entire specimen image and at the single cell level. Our results demonstrate discrete subpopulations with specific regional localization with respect to blood vessels and to each other. In particular, highly proliferative Nestin-positive cells are preferentially located near blood vessels. These cells do not express GLUT1 and are Hif-1a positive. In contrast, GLUT1-positive cells are negative for Nestin, demonstrate low proliferation, and are preferentially located at the zones of pseudopalisading necrosis, furthest from blood vessels. In addition, GLUT1-positive cells show reduced Hif-1a expression compared to Nestin-positive cells. Our novel approach provides a means to identify, characterize, and monitor the changing nature of GBM before and after various treatment modalities with the ultimate aim of revealing selective vulnerabilities in order to retard or cure this neoplasm.

Much of our understanding of CNS immunity has been gained from models involving pathological inflammation. Attenuated rabies viruses (RABV) are unique tools to study CNS immunity in the absence of conventional inflammatory mechanisms, as they spread from the site of inoculation to the CNS transaxonally, thereby bypassing the blood–brain barrier (BBB), and are cleared without neutrophil or monocyte infiltration. To better understand the role of CD4 T cell subsets in the clearance of the virus from CNS tissues, we examined the development of antiviral immunity in wild-type (WT) and T-bet knockout mice (T-bet−/−), which lack Th1 cells. Early control of RABV replication in the CNS tissues of WT mice is associated with the production of IFN-γ, with antiviral effects likely mediated through the enhanced expression of type I IFNs. Of interest, IFN-α and -γ are overexpressed in the infected T-bet−/− by comparison with WT CNS tissues, and the initial control of RABV infection is similar. Ultimately, attenuated RABV are cleared from the CNS tissues of WT mice by Ab locally produced by the activities of infiltrating T and B cells. Although T and B cell infiltration into the CNS of infected T-bet−/− mice is comparable, their activities are not, the consequence being delayed, low-level Ab production and prolonged RABV replication. More importantly, neither T-bet−/− mice immunized with an attenuated virus, nor WT mice with Th2 RABV-specific immunity induced by immunization with inactivated virus, are protected in the long term against challenge with a pathogenic RABV.

Rabies remains a major public health issue worldwide, especially in developing countries where access to medical care can represent a real challenge. While there is still no cure for rabies, it is a vaccine-preventable disease with pre- and post-exposure prophylaxis regimens approved by the World Health Organization (WHO). However, many rabies-exposed individuals have limited access to vaccines and virus-neutralizing antibodies approved for post-exposure prophylaxis. Unfortunately, any delay in the administration of these reagents can have lethal consequences. This highlights the need to develop cost-effective immunological reagents with a greater window of efficacy. Live-attenuated vaccine strains of rabies virus presents a potential treatment in filling this gap. We show here that immunization with live-attenuated vaccines provide long-lasting rabies immunity, superior to the protection induced by inactivated vaccines. In the absence of an immunostimulatory adjuvant, vaccination with multiple doses of inactivated rabies virus induces a type-2 immune response. This type of immunity is highly effective at inducing neutralizing antibody but has limited efficacy in clearing the virus from central nervous system (CNS) tissues. In contrast, a single infection with live-attenuated rabies vaccine safely drives a type-1 immune response, associated with both the production of a neutralizing antibody and the clearance of wild-type rabies virus from CNS tissues. These results indicate that live-attenuated rabies strains have the potential to be more effective in post-exposure prophylaxis than conventional inactivated vaccines.

Background: We evaluated an autologous cell vaccine, a combination of GBM tumor cells and an antisense molecule against insulin-like growth factor type 1 receptor DNA/mRNA (IGF-1R AS ODN), in adults with newly diagnosed GBM (NCT02507583). Methods: Tumor cells collected during resection were treated ex vivo with IGF-1R AS ODN, encapsulated in biodiffusion chambers with IGF-1R AS ODN, irradiated, then implanted in an abdominal acceptor site on the first post-operative day. Four vaccine exposures were evaluated: lowest (10 chambers implanted for 24 hours); lower (10 / 48 hours); higher (20 / 24 hours); and highest (20 / 48 hours). Standard of care (SOC; ie, radiotherapy and temozolomide) was initiated after 4-6 weeks. Randomization was halted after patient 23 and subsequent patients received the highest exposure. Evaluation of safety and tumor responses were the primary and secondary objectives, respectively. Exploratory objectives included assessment of progression-free survival (PFS) and overall survival (OS). The SOC comparator group was an antecedent cohort of 35 newly diagnosed, GBM patients treated at the same center. Results: Thirty-three patients were enrolled between September 1, 2015 and March 1, 2018. Six, 5, 5, and 17 patients received the lowest, lower, higher, and highest exposures. Median (range) follow-up was 13 (4-39) months. As of the January 1, 2019 cutoff, no vaccine-related adverse events were observed. Seventeen of 33 (51.5%) remained progression-free, 12 of whom are alive and functioning well. The autologous cell vaccine significantly prolonged PFS and OS vs. SOC (Table). Survival advantages were conferred by the highest exposure to the autologous cell vaccine and good T cell function prior to surgery. Conclusions: This vaccine was well-tolerated and prolonged PFS and OS when compared with SOC alone. Table.Survival outcomes in patients receiving vaccine vs. SOC aloneTreatment group2 yr OS estimateMedian OS (mo)p-value v. SOC for OS1 yr PFS estimateMedian PFS estimatep-value v. SOC for PFSVaccine highest dose (N=17)34%21.9.04141%10.4.031Vaccine all (ITT, N=33)31%17.3.01642%9.8.018SOC (n=35)14%12.128%6.9 Citation Format: David W. Andrews, Samantha Garcia, Kevin D. Judy, Larry A. Harshyne, Sanjana Govindarajan, Lawrence Kenyon, Kiran Talekar, Adam Flanders, Kofi-Buaku Atsina, Lyndon Kim, Nina L. Martinez, Wenyin Shi, Maria Werner-Wasik, Mikhail Prosniak, Mark T. Curtis, Rhonda Kean, Emily Bongiorno, Sami Sauma, Kara Pigott, Charles B. Scott, D Craig Hooper. Results of a Phase Ib trial of an autologous cell vaccine for newly diagnosed glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT038.

Purpose: This study is directed at identifying the cell source(s) of immunomodulatory cytokines in high-grade gliomas and establishing whether the analysis of associated markers has implications for tumor grading. Experimental Design: Glioma specimens classified as WHO grade II–IV by histopathology were assessed by gene expression analysis and immunohistochemistry to identify the cells producing interleukin (IL)-10, which was confirmed by flow cytometry and factor secretion in culture. Finally, principal component analysis (PCA) and mixture discriminant analysis (MDA) were used to investigate associations between expressed genes and glioma grade. Results: The principle source of glioma-associated IL-10 is a cell type that bears phenotype markers consistent with M2 monocytes but does not express all M2-associated genes. Measures of expression of the M2 cell markers CD14, CD68, CD163, and CD204, which are elevated in high-grade gliomas, and the neutrophil/myeloid-derived suppressor cell (MDSC) subset marker CD15, which is reduced, provide the best index of glioma grade. Conclusions: Grade II and IV astrocytomas can be clearly differentiated on the basis of the expression of certain M2 markers in tumor tissues, whereas grade III astrocytomas exhibit a range of expression between the lower and higher grade specimens. The content of CD163+ cells distinguishes grade III astrocytoma subsets with different prognosis. Clin Cancer Res; 19(14); 3776–86. ©2013 AACR.

Immunotherapeutic strategies for malignant glioma have to overcome the immunomodulatory activities of M2 monocytes that appear in the circulation and as tumor-associated macrophages (TAMs). M2 cell products contribute to the growth-promoting attributes of the tumor microenvironment (TME) and bias immunity toward type 2, away from the type 1 mechanisms with antitumor properties. To drive type 1 immunity in CNS tissues, we infected GL261 tumor–bearing mice with attenuated rabies virus (RABV). These neurotropic viruses spread to CNS tissues trans-axonally, where they induce a strong type 1 immune response that involves Th1, CD8, and B cell entry across the blood–brain barrier and virus clearance in the absence of overt sequelae. Intranasal infection with attenuated RABV prolonged the survival of mice bearing established GL261 brain tumors. Despite the failure of virus spread to the tumor, infection resulted in significantly enhanced tumor necrosis, extensive CD4 T cell accumulation, and high levels of the proinflammatory factors IFN-γ, TNF-α, and inducible NO synthase in the TME merely 4 d postinfection, before significant virus spread or the appearance of RABV-specific immune mechanisms in CNS tissues. Although the majority of infiltrating CD4 cells appeared functionally inactive, the proinflammatory changes in the TME later resulted in the loss of accumulating M2 and increased M1 TAMs. Mice deficient in the Th1 transcription factor T-bet did not gain any survival advantage from RABV infection, exhibiting only limited tumor necrosis and no change in TME cytokines or TAM phenotype and highlighting the importance of type 1 mechanisms in this process.

Tumor-associated macrophages (TAMs) are the most abundant inflammatory cells in the breast cancer (BC) tumor microenvironment (TME) and suppress antitumor immune function, contributing to treatment resistance. These M2-polarized macrophages are characterized by fatty acid oxidation as opposed to the glycolytic pathways associated with M1-polarization. MiR-21 is known to affect several metabolic pathways relevant to macrophage polarization. We have previously shown that caloric restriction (CR) can decrease miR-21 expression and increase response to radiation therapy (RT). We propose CR as a means of metabolically reprogramming TAMs toward M1 phenotype to increase efficacy of radiation therapy (RT). To assess the effects of CR in vivo on the composition of the TME in breast cancer, 40 female Balb/c mice were orthotopically injected at 12 weeks old with 4T1 cells and assigned to one of four cohorts: ad lib (AL) fed, 8 Gy RT to the primary tumor (RT), 30% reduction in caloric intake (CR) or CR+RT. MiR-21 levels were significantly decreased in both the CR and CR+RT arms; however, miR-21 was increased in the RT arm. Increased expression of M2 markers was noted in tumors in the RT group as compared to the CR and CR+RT groups, which favored M1 markers. On microarray analysis, the top pathways affected by CR discovered by gene ontology pathway analysis were: inflammation mediated by chemokine and cytokine signaling (31/509 hits), Wnt signaling (21/509 hits) and apoptotic signaling (18/509 hits). Multiple genes related to macrophage polarization were altered by CR including Ccl2 and IL12A. IL-12 is a known target of miR-21, and CR decreases miR-21 expression, therefore we sought to determine if miR-21 may be the mechanism behind the shift in chemokine and cytokine expression in the TME. Cohorts of MMTV-PyMT mice with spontaneously developed breast tumors were bred with a miR-21-/- mouse to generate breast tumors that lack expression of miR-21. These tumors exhibited high levels of IL-12 as well as IL-23 and Cxcl10, all of which are associated with M1 phenotype. MiR-21+/+ tumors exhibited high levels of IL-4 and TGF-β, both associated with M2 phenotype. In addition, peripheral monocytes (PBMCs) were co-cultured with sera from each of the following mice: miR-21-/-, miR-21+/+, AL, RT, CR and CR+RT. M1-polarization was induced by sera from miR-21-/- mice as well as mice receiving CR alone and CR+RT. Ionizing radiation seemed to induce M2-polarization in this manner, as did the miR-21+/+ serum. Taken together, these data suggest that CR can counteract the M2-polarization caused by RT in the TME. This is likely due, in part, to miR-21 downregulation leading to enhanced M1 response. By increasing M1-polarized macrophages and enhancing antitumor immunity, we believe CR is a viable adjunct to standard cytotoxic therapies that could help overcome resistance to chemotherapy and immunotherapy. Citation Format: Brittany A. Simone, Tiziana DeAngelis, Ajay Palagani, Kevin Ko, Larry Harshyne, D. Craig Hooper, Adam P. Dicker, Nicole L. Simone. Caloric restriction promotes antitumor immunity through polarization of intratumoral macrophages to M1 phenotype via downregulation of miR-21 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 71.

TPS8582Background: For patients (pts) with stage IB (≥4cm)-IIIA Non-small-cell lung cancer (NSCLC), multi-modality therapy yields a modest improvement in 5 year post-surgical overall survival (OS),...

Globoid cell leukodystrophy (GLD) or Krabbe disease is a neurodegenerative disorder caused by the deficiency of the lysosomal enzyme galactocerebrosidase (GALC). GALC deficiency results in a progressive demyelination of the central and peripheral nervous systems. Inflammatory cells and increased levels of cytokines and chemokines are present in the CNS of GLD mice and may play a significant role in the pathogenesis of the disease. In this study we evaluate the effect of non-steroidal anti-inflammatory drugs, such as indomethacin and ibuprofen, and minocycline, a tetracycline analog with neuroprotective and anti-apoptotic properties, on the progression of the disease using a transgenic mouse model of GLD. Real-time quantitative PCR was used to analyze the expression of several markers of the immune/inflammatory response. IL-6, TNF-alpha, MIP-1beta, MCP-1, iNOS/NOS2, CD11b, CD68, CD4 and CD8 mRNA levels were measured in cortex, cerebellum and spinal cord of untreated and treated affected mice at different ages. In addition, the pharmacological treatments were compared to bone marrow transplantation (BMT). The pharmacological treatments significantly extended the life-span of the treated mice and reduced the levels of several of the immuno-related factors studied. However, BMT produced the most dramatic improvements. In BMT-treated mice, factors in the spinal cord were normalized faster than the cerebellum, with the exception of CD68. There was a decrease in the number of apoptotic cells in the cerebellum of mice receiving anti-inflammatory drugs and BMT. These studies indicate a possible role for combined therapy in the treatment of GLD.

The objective of this study is to evaluate the safety and tolerability of inosine in patients with relapsing-remitting multiple sclerosis (RRMS). The secondary objectives are to assess the effects of inosine administration on serum urate (UA) levels, the progression of neurologic disability, the cumulative number of new, active lesions on magnetic resonance imaging (MRI), and changes in serum levels for markers of inflammation.Oral administration of inosine was used to raise serum levels of the natural peroxynitrite scavenger UA in 16 patients with RRMS during a 1-year randomized, double-blind trial.The endpoints studied were relapse rate, disability assessed by the Kurtzke Expanded Disability Status Scale (EDSS), MRI, and analysis of serum levels of nitrotyrosine, and oxidative and pro-inflammatory makers.Increased serum UA levels correlated with a significant decrease in the number of gadolinium-enhanced lesions and improved EDSS. A number of MRI intensity-based parameters were altered by inosine treatment, in certain cases correlating with changes in serum UA levels. In a patient with low serum UA and high lesion activity, raising UA levels by inosine treatment decreased serum nitrotyrosine while increasing the ratio of Th2 to Th1 cytokines in circulating cells. The only side-effect correlated with inosine treatment was kidney stone formation in 4/16 subjects.These data suggest that the use of inosine to raise serum UA levels may have benefits for at least some MS patients. The effect of this treatment is likely to be a consequence of inactivation of peroxynitrite-dependent free radicals. Close monitoring of serum UA levels as well as other measures are required to avoid the potential development of kidney stones.