YY1 mutations disrupt corticogenesis through a cell-type specific rewiring of cell-autonomous and non-cell-autonomous transcriptional programs

Germline mutations of YY1 cause Gabriele-de Vries syndrome (GADEVS), a neurodevelopmental disorder featuring intellectual disability and a wide range of systemic manifestations. To dissect the cellular and molecular mechanisms underlying GADEVS, we combined large-scale imaging, single-cell multiomics and gene regulatory network reconstruction in 2D and 3D patient-derived physiopathologically relevant cell lineages. YY1 haploinsufficiency causes a pervasive alteration of cell type specific transcriptional networks, disrupting corticogenesis at the level of neural progenitors and terminally differentiated neurons, including cytoarchitectural defects reminiscent of GADEVS clinical features. Transcriptional alterations in neurons propagated to neighboring astrocytes through a major non-cell autonomous pro-inflammatory effect that grounds the rationale for modulatory interventions. Together, neurodevelopmental trajectories, synaptic formation and neuronal-astrocyte cross talk emerged as salient domains of YY1 dosage-dependent vulnerability. Mechanistically, cell-type resolved reconstruction of gene regulatory networks uncovered the regulatory interplay between YY1, NEUROG2 and ETV5 and its aberrant rewiring in GADEVS. Our findings underscore the reach of advanced in vitro models in capturing developmental antecedents of clinical features and exposing their underlying mechanisms to guide the search for targeted interventions.

Reassessment of the NF1 variants of unknown significance found during the 20-year activity of a genetics diagnostic laboratory

The finding of variants of uncertain significance (VUS) in the activity of a diagnostic genetic laboratory is a common issue, which is however provisional and needs to be periodically re-evaluated, due to the continuous advancements in our knowledge of the genetic diseases. Neurofibromatosis type 1, caused by the occurrence of heterozygous pathogenic NF1 variants, is a good model for studying the evolution of VUS, due to the widespread use of genetic testing for the disease, the constant enrichment of the international databases with NF1 variants and the full adult penetrance of the disease, which makes genotyping the parents a crucial step in the diagnostic workflow. The present study retrospectively reviewed and reinterpreted the genetic test results of NF1 in a diagnostic genetic laboratory in the period from January 1, 2000 to December 31, 2020. All the VUS were reinterpreted using the 2015 consensus standards and guidelines for the interpretation. Out of 589 NF1 genetic tests which were performed in the period, a total of 85 VUS were found and reinterpreted in 72 cases (84.7%): 21 (29.2%) were reclassified as benign/likely benign, whereas 51 (70.8%) were recoded as pathogenic/likely pathogenic with a significant trend distribution (Chi square test for trend p = 0.005). Synonymous VUS have mainly been reclassified as class 1 and 2 (7/8, 87.5%), whereas missense variants have been attributed to class 4 and 5 in 38 out of the 58 cases (65.5%). These findings underline an improvement in the classification of variants over time, suggesting that a reinterpretation of the genetic tests should be routinely performed to support the physicians in the clinical diagnosis of genetic diseases.

Toward more accurate preclinical glioblastoma modeling: Reverse translation of clinical standard of care in a glioblastoma mouse model

Glioblastoma (GBM) is the deadliest of all brain cancers. GBM patients receive an intensive treatment schedule consisting of surgery, radiotherapy and chemotherapy, which only modestly extends patient survival. Therefore, preclinical studies are testing novel experimental treatments. In such preclinical studies, these treatments are administered as monotherapy in the majority of cases; conversely, in patients the new treatments are always combined with the standard of care. Most likely, this difference contributes to the failure of clinical trials despite the successes of the preclinical studies. In this methodological study, we show in detail how to implement the full clinical standard of care in preclinical GBM research. Systematically testing new treatments, including cellular immunotherapies, in combination with the clinical standard of care can result in a better translation of preclinical results to the clinic and ultimately increase patient survival.

Preclinical studies performed in appropriate models could help identify optimal timing of combined chemotherapy and immunotherapy

Immune checkpoint inhibitors (ICI) have been revolutionary in the field of cancer therapy. However, their success is limited to specific indications and cancer types. Recently, the combination treatment of ICI and chemotherapy has gained more attention to overcome this limitation. Unfortunately, many clinical trials testing these combinations have provided limited success. This can partly be attributed to an inadequate choice of preclinical models and the lack of scientific rationale to select the most effective immune-oncological combination. In this review, we have analyzed the existing preclinical evidence on this topic, which is only limitedly available. Furthermore, this preclinical data indicates that besides the selection of a specific drug and dose, also the sequence or order of the combination treatment influences the study outcome. Therefore, we conclude that the success of clinical combination trials could be enhanced by improving the preclinical set up, in order to identify the optimal treatment combination and schedule to enhance the anti-tumor immunity.

Radiation dose-escalation and dose-fractionation modulate the immune microenvironment, cancer stem cells and vasculature in experimental high-grade gliomas

BACKGROUND

In the context of high-grade gliomas (HGGs), very little evidence is available concerning the optimal radiotherapy (RT) schedule to be used in radioimmunotherapy combinations. This studied was aimed at shedding new light in this field by analyzing the effects of RT dose escalation and dose fractionation on the tumor microenvironment of experimental HGGs.

METHODS

Neurospheres (NS) CT-2A HGG-bearing C57BL/6 mice were treated with stereotactic RT. For dose-escalation experiments, mice received 2, 4 or 8 Gy as single administrations. For dose-fractionation experiments, mice received 4 Gy as a single fraction or multiple (1.33x3 Gy) fractions. The impact of the RT schedule on murine survival and tumor immunity was evaluated. Modifications of glioma stem cells (GSCs), tumor vasculature and tumor cell replication were also assessed.

RESULTS

RT dose-escalation was associated with an improved immune profile, with higher CD8⁺ T cells and CD8⁺ T cells/regulatory T cells (Tregs) ratio (P=0.0003 and P=0.0022, respectively) and lower total tumor associated microglia/macrophages (TAMs), M2 TAMs and monocytic myeloid derived suppressor cells (mMDSCs) (P=0.0011, P=0.0024 and P<0.0001, respectively). The progressive increase of RT dosages prolonged survival (P<0.0001) and reduced tumor vasculature (P=0.069), tumor cell proliferation (P<0.0001) and the amount of GSCs (P=0.0132 or lower). Compared to the unfractionated regimen, RT dose-fractionation negatively affected tumor immunity by inducing higher total TAMs, M2 TAMs and mMDSCs (P=0.0051, P=0.0036 and P=0.0436, respectively). Fractionation also induced a shorter survival (P=0.0078), a higher amount of GSCs (P=0.0015 or lower) and a higher degree of tumor cell proliferation (P=0.0003).

CONCLUSIONS

This study demonstrates that RT dosage and fractionation significantly influence survival, tumor immunity and GSCs in experimental HGGs. These findings should be taken into account when aiming at designing more synergistic and effective radio-immunotherapy combinations.

Intraperitoneal alpha therapy with 224Ra-labeled microparticles combined with chemotherapy in an ovarian cancer mouse model

A novel alpha-therapy consisting of ²²⁴Ra-labeled calcium carbonate microparticles (²²⁴Ra-CaCO₃-MP) has been designed to treat micrometastatic peritoneal disease via intraperitoneal (IP) administration. This preclinical study aimed to evaluate its efficacy and tolerability when given as a single treatment or in combination with standard of care chemotherapy regimens, in a syngeneic model of ovarian cancer in immune competent mice. Female C57BL/6 mice bearing ID8-fLuc ovarian cancer were treated with ²²⁴Ra-CaCO₃-MP 1 day after IP tumor cell inoculation. The activity dosages of ²²⁴Ra ranged from 14 to 39 kBq/mouse. Additionally, ²²⁴Ra-CaCO₃-MP treatment was followed by either carboplatin (80 mg/kg)-pegylated liposomal doxorubicin (PLD, 1.6 mg/kg) or carboplatin (60 mg/kg)-paclitaxel (10 mg/kg) on day 14 post tumor cell inoculation. All treatments were administered via IP injections. Readouts included survival, clinical signs, and body weight development over time. There was a slight therapeutic benefit after single treatment with ²²⁴Ra-CaCO₃-MP compared to the vehicle control, with median survival ratios (MSRs) ranging between 1.1 and 1.3. The sequential administration of ²²⁴Ra-CaCO₃-MP with either carboplatin-paclitaxel or carboplatin-PLD indicated a synergistic effect on overall survival at certain ²²⁴Ra activities. Moreover, the combinations tested appeared well tolerated in terms of weight assessment in the first 4 weeks after treatment. Overall, this research supports the further evaluation of ²²⁴Ra-CaCO₃-MP in patients with ovarian cancer. However, the most optimal chemotherapy regimen to combine with ²²⁴Ra-CaCO₃-MP should be identified to fully exploit its therapeutic potential.

Selective Cerebrospinal Fluid Hypothermia: Bioengineering Development and In Vivo Study of an Intraventricular Cooling Device (V-COOL)

Hypothermia is a promising therapeutic strategy for severe vasospasm and other types of non-thrombotic cerebral ischemia, but its clinical application is limited by significant systemic side effects. We aimed to develop an intraventricular device for the controlled cooling of the cerebrospinal fluid, to produce a targeted hypothermia in the affected cerebral hemisphere with a minimal effect on systemic temperature. An intraventricular cooling device (acronym: V-COOL) was developed by in silico modelling, in vitro testing, and in vivo proof-of-concept application in healthy Wistar rats (n = 42). Cerebral cortical temperature, rectal temperature, and intracranial pressure were monitored at increasing flow rate (0.2 to 0.8 mL/min) and duration of application (10 to 60 min). Survival, neurological outcome, and MRI volumetric analysis of the ventricular system were assessed during the first 24 h. The V-COOL prototyping was designed to minimize extra-cranial heat transfer and intra-cranial pressure load. In vivo application of the V-COOL device produced a flow rate-dependent decrease in cerebral cortical temperature, without affecting systemic temperature. The target degree of cerebral cooling (- 3.0 °C) was obtained in 4.48 min at the flow rate of 0.4 mL/min, without significant changes in intracranial pressure. Survival and neurological outcome at 24 h showed no significant difference compared to sham-treated rats. MRI study showed a transient dilation of the ventricular system (+ 38%) in a subset of animals. The V-COOL technology provides an effective, rapid, selective, and safe cerebral cooling to a clinically relevant degree of - 3.0 °C.

Artificial intelligence-based radiomics on computed tomography of lumbar spine in subjects with fragility vertebral fractures

PURPOSE

There is emerging evidence that radiomics analyses can improve detection of skeletal fragility. In this cross-sectional study, we evaluated radiomics features (RFs) on computed tomography (CT) images of the lumbar spine in subjects with or without fragility vertebral fractures (VFs).

METHODS

Two-hundred-forty consecutive individuals (mean age 60.4 ± 15.4, 130 males) were evaluated by radiomics analyses on opportunistic lumbar spine CT. VFs were diagnosed in 58 subjects by morphometric approach on CT or XR-ray spine (D4-L4) images. DXA measurement of bone mineral density (BMD) was performed on 17 subjects with VFs.

RESULTS

Twenty RFs were used to develop the machine learning model reaching 0.839 and 0.789 of AUROC in the train and test datasets, respectively. After correction for age, VFs were significantly associated with RFs obtained from non-fractured vertebrae indicating altered trabecular microarchitecture, such as low-gray level zone emphasis (LGLZE) [odds ratio (OR) 1.675, 95% confidence interval (CI) 1.215-2.310], gray level non-uniformity (GLN) (OR 1.403, 95% CI 1.023-1.924) and neighboring gray-tone difference matrix (NGTDM) contrast (OR 0.692, 95% CI 0.493-0.971). Noteworthy, no significant differences in LGLZE (p = 0.94), GLN (p = 0.40) and NGDTM contrast (p = 0.54) were found between fractured subjects with BMD T score < - 2.5 SD and those in whom VFs developed in absence of densitometric diagnosis of osteoporosis.

CONCLUSIONS

Artificial intelligence-based analyses on spine CT images identified RFs associated with fragility VFs. Future studies are needed to test the predictive value of RFs on opportunistic CT scans in identifying subjects with primary and secondary osteoporosis at high risk of fracture.

Overexpressed beta cell CART increases insulin secretion in mouse models of insulin resistance and diabetes

Impaired beta cell function and beta cell death are key features of type 2 diabetes (T2D). Cocaine- and amphetamine-regulated transcript (CART) is necessary for normal islet function in mice. CART increases glucose-stimulated insulin secretion in vivo in mice and in vitro in human islets and CART protects beta cells against glucotoxicity-induced cell death in vitro in rats. Furthermore, beta cell CART is upregulated in T2D patients and in diabetic rodent models as a consequence of hyperglycaemia. The aim of this study was to assess the impact of upregulated beta cell CART on islet hormone secretion and glucose homeostasis in a transgenic mouse model. To this end, mice with beta cell-specific overexpression of CART (CARTtg mice) were generated. CARTtg mice challenged by aging, high fat diet feeding or streptozotocin treatment were phenotyped with respect to in vivo and in vitro insulin and glucagon secretion, glucose homeostasis, and beta cell mass. In addition, the impact of adenoviral overexpression of CART on insulin secretion was studied in INS-1 832/13 cells. CARTtg mice had a normal metabolic phenotype under basal conditions. On the other hand, with age CARTtg mice displayed increased insulin secretion and improved glucose elimination, compared with age-matched WT mice. Furthermore, compared with WT controls, CARTtg mice had increased insulin secretion after feeding a high fat diet, as well as lower glucose levels and higher insulin secretion after streptozotocin treatment. Viral overexpression of CART in INS-1 832/13 cells resulted in increased glucose-stimulated insulin secretion. Together, these results imply that beta cell CART acts to increase insulin secretion when beta cell function is challenged. We propose that the increase in beta cell CART is part of a compensatory mechanisms trying to counteract the hyperglycaemia in T2D.

Internal medicine inpatients' prevalence of misdiagnosed severe osteoporosis

Vertebral fractures (VF) related to osteoporosis (i.e., severe OP) increase the risk of disability and mortality, but they are often neglected. We observed a severe OP misdiagnosis in 28.9% of inpatients with previous spinal imaging positive for VFs. Diagnosing severe OP is crucial to reduce the health care costs of inpatients.

INTRODUCTION

Vertebral fractures (VFs) related to osteoporosis (OP) increase the risk of additional fractures and death. In inpatients, VFs are often neglected with consequent delay in OP treatments, prolongation of hospitalization, and reduction of life expectancy. The aim of this study was to evaluate the prevalence of a misdiagnosed severe OP (i.e., with VF) in general medicine inpatients.

METHODS

We evaluated inpatients of a Medicine Unit between January 2019 and December 2019 without severe OP diagnosis, who had spinal imaging. For each patient, we collected demographic data, previous or current OP treatment, and presence/number of VFs. Descriptive data were presented by medians (interquartile range [IQR]) for continuous data or as numbers (percentages) for categorical data. Differences between subgroups were analyzed with chi-square or Kruskal-Wallis tests as appropriate. p-values <0.05 were considered statistically significant.

RESULTS

793 subjects were admitted to inpatient's clinic: 235 (135 females and 100 males with a median age of 76.0 [64.0-83.0] years) were enrolled. One or more vertebral fractures were present in 28.9% (68/235) subjects; 47% (32/68) had two or more vertebral fractures. The majority of patients (55/68) with VFs had not previously received a severe OP diagnosis.

CONCLUSIONS

Severe OP was misdiagnosed in at least 8.6% of inpatients. The prevalence dramatically increases (about 29%) in subjects with previous spinal imaging showing one or more VFs. More attention should be given to this co-morbidity, which is known to be an additional risk factor for disability and mortality.

Filgotinib as rheumatoid arthritis therapy

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint inflammation and progressive disability when inflammation cannot be sufficiently controlled. Despite treatment with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and biological DMARDs (bDMARDs), up to 30% of RA patients do not reach or fail to maintain a good response over time. The recent introduction of Janus kinase inhibitors (JAKis) has widened the rheumatologist's armamentarium. Filgotinib, a selective JAK1 inhibitor, has been approved by the European Medicines Agency (EMA) for treatment of RA. Phase II and III studies highlighted filgotinib safety and efficacy in RA patients naive to DMARDs or with inadequate response to csDMARDs and bDMARDs. Filgotinib is administered orally at 200 mg every day. For patients older than 75 years or with moderate to severe renal impairment, a dose of filgotinib 100 mg every day is recommended.

Recurrent NF1 gene variants and their genotype/phenotype correlations in patients with Neurofibromatosis type I

Neurofibromatosis type I, a genetic condition due to pathogenic variants in the NF1 gene, is burdened by a high rate of complications, including neoplasms, which increase morbidity and mortality for the disease. We retrospectively re-evaluated the NF1 gene variants found in the period 2000-2019 and we studied for genotype/phenotype correlations of disease complications and neoplasms 34 variants, which were shared by at least two unrelated families (range 2-11) for a total 141 of probands and 21 relatives affected by Neurofibromatosis type I. Recurrent variants could be ascribed to the most common mutational mechanisms (C to T transition, microsatellite slippage, non-homologous recombination). In genotype/phenotype correlations, the variants p.Arg440*, p.Tyr489Cys, and p.Arg1947*, together with the gross gene deletions, displayed the highest rates of complications. When considering neoplasms, carriers of variants falling in the extradomain region at the 5' end of NF1 had a lower age-related cancer frequency than the rest of the gene sequence, showing a borderline significance (p = 0.045), which was not conserved after correction with covariates. We conclude that (1) hotspots in NF1 occur via different mutational mechanisms, (2) several variants are associated with high rates of complications and cancers, and (3) there is an initial evidence toward a lower cancer risk for carriers of variants in the 5' end of the NF1 gene although not significant at the multivariate analysis.

Abstract 1797: Preclinical characterization of Sym024, a novel anti-CD73 antibody

Tumor cells are surrounded by a complex microenvironment (the tumor microenvironment, or TME) that influences each step of tumorigenesis. In the TME, increased concentrations of immune modulating factors such as adenosine help tumor cells evade host anti-tumor immune responses. Adenosine binds to adenosine receptors (ARs) expressed on various immune cells such as CD4+ and CD8+ T cells, myeloid cells and natural killer (NK) cells. These receptors exhibit distinct properties and cell and tissue distribution. Binding of adenosine to a subset of ARs suppresses the anti-tumor responses of T cells and NK cells and augments the activity of immunosuppressive cells such as regulatory T cells and myeloid-derived suppressor cells, thus promoting tumor progression. The generation of adenosine in the TME is mediated by a group of ectonucleotidases, including CD39 and CD73, which work in a common pathway converting extracellular ATP to adenosine. CD73 is frequently overexpressed on human tumor cells and mediates the hydrolysis of AMP to adenosine, particularly under hypoxic conditions. Importantly, CD73 overexpression correlates with poorer prognosis in various cancers, including lung, gastric, head and neck, pancreatic, cholangiocarcinoma, colorectal, bladder, triple negative breast, ovarian, and kidney cancer, and melanoma. Inhibition of the enzymatic activity of CD73 therefore represents an attractive way of relieving the immune suppressive activity of adenosine in the TME.Sym024 is an Fc-attenuated human monoclonal antibody that binds to human and cynomolgus monkey CD73 with sub-nanomolar avidity. Sym024 binds to a distinct epitope on the enzyme on the opposite side relative to the catalytic center and potently inhibits the activity of soluble CD73 as well as CD73 expressed on numerous cancer cell lines and primary lymphocytes. Importantly, CD73 inhibition by Sym024 alleviates AMP-mediated inhibition of T cell proliferation and activation. In vitro one-way mixed lymphocyte reaction results demonstrate the utility of combining CD73 inhibition with PD-1 blockade, as Sym024 acts to reverse the immune suppressive effect of adenosine production, thereby allowing effective T cell activation by an anti-PD-1 antibody (Sym021). Mechanistically, Sym024 inhibits cellular CD73 by direct enzymatic inhibition with moderate shedding or degradation of CD73 in vitro. In preclinical in vivo tumor models, Sym024 effectively inhibits CD73 activity and tumor growth. Sym024 was well tolerated with no observed toxicity in repeat dose studies in monkeys at dose levels up to 100 mg/kg. Dose-proportional and linear pharmacokinetics (PK) was observed at high dose levels while nonlinear PK became evident at lower exposure levels. Sym024 is currently under clinical investigation.

Citation Format: Janus S. Jakobsen, Matteo Riva, Maria C. Melander, Randi W. Hansen, Klaus Kofoed, Mikkel W. Pedersen, Jutta Deckert, Lene Hansen, Niels Jorgen Skartved, Johan Lantto, Camilla Frohlich, Michael Monrad Grandal. Preclinical characterization of Sym024, a novel anti-CD73 antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1797.

CryptoCEST: A promising tool for spatially resolved identification of fungal brain lesions and their differentiation from brain tumors with MRI

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The fungal disaccharide trehalose generates a concentration-dependent CEST MRI contrast.

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CEST MRI can detect endogenous trehalose in Cryptococcus neoformans and C. gattii cells.

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This enables spatially resolved identification of fungal lesions in the mouse brain.

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The CryptoCEST contrast can differentiate cryptococcal brain lesions from gliomas.

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CryptoCEST holds potential for non-invasive differential diagnosis of cryptococcomas.

Infectious brain lesions caused by the pathogenic fungi Cryptococcus neoformans and C. gattii, also referred to as cryptococcomas, could be diagnosed incorrectly as cystic brain tumors if only based on conventional magnetic resonance (MR) images. Previous MR spectroscopy (MRS) studies showed high local concentrations of the fungal disaccharide trehalose in cryptococcomas. The aim of this study was to detect and localize fungal brain lesions caused by Cryptococcus species based on Chemical Exchange Saturation Transfer (CEST) MR imaging of endogenous trehalose, and hereby to distinguish cryptococcomas from gliomas. In phantoms, trehalose and cryptococcal cells generated a concentration-dependent CEST contrast in the 0.2 – 2 ppm chemical shift range, similar to glucose, but approximately twice as strong. In vivo single voxel MRS of a murine cryptococcoma model confirmed the presence of trehalose in cryptococcomas, but mainly for lesions that were large enough compared to the size of the MRS voxel. With CEST MRI, combining the more specific CEST signal at 0.7 ppm with the higher signal-to-noise ratio signal at 4 ppm in the CryptoCEST contrast enabled localization and distinction of cryptococcomas from the normal brain and from gliomas, even for lesions smaller than 1 mm³. Thanks to the high endogenous concentration of the fungal biomarker trehalose in cryptococcal cells, the CryptoCEST contrast allowed identification of cryptococcomas with high spatial resolution and differentiation from gliomas in mice. Furthermore, the CryptoCEST contrast was tested to follow up antifungal treatment of cryptococcomas. Translation of this non-invasive method to the clinic holds potential for improving the differential diagnosis and follow-up of cryptococcal infections in the brain.

Type of chemotherapy has substantial effects on the immune system in ovarian cancer

Chemotherapy induces a variety of immunological changes. Studying these effects can reveal opportunities for successful combining chemotherapy and immunotherapy. Immuno-chemotherapeutic combinations in ovarian cancer are currently not generating the anticipated positive effects. To date, only scattered and inconsistent information is available about the immune-induced changes by chemotherapy in ovarian cancer. In this study, we compared six common chemotherapeutics used in ovarian cancer patients (carboplatin, paclitaxel, pegylated liposomal doxorubicin, gemcitabine, carboplatin-paclitaxel and carboplatin-gemcitabine) and studied their effects on the immune system in an ovarian cancer mouse model. Mice received a single chemotherapy or vehicle injection 21 days after tumor inoculation with ID8-fluc cells. One week after therapy administration, we collected peritoneal washings for flow cytometry, serum for cytokine analysis with cytometric bead array and tumor biopsies for immunohistochemistry. Carboplatin-paclitaxel showed the most favorable profile with a decrease in immunosuppressive cells in the peritoneal cavity and an increase of interferon-gamma in serum. In contrast, carboplatin-gemcitabine seemed to promote a hostile immune environment with an increase in regulatory T-cells in tumor tissue and an increase of macrophage-inflammatory-protein-1-beta in the serum.

AB0578 SUBCLINICAL ENTHESITIS IN PSORIASIS patiEntS AS prediCtor OF ARTHRITIS (EPESCA STUDY): PRELIMINARY RESULTS

Background:

Enthesitis is one of the typical pathological signs of spondyloarthritis such as psoriatic arthritis (PsA) and it seems to be the Primum movens of the disease. Clinical assessment of enthesitis showed to be less sensitive, compared to ultrasound (US) evaluation, in identifying enthesitis in patients with PsA [1].

OMERACT defined US enthesitis as: “hypoechoic and/or thickened insertion of the tendon close to the bone (within 2 mm from the bony cortex), which exhibits Doppler signal if active and that may show erosions, enthesophytes/calcifications as a sign of structural damage” [3]

The reported prevalence of subclinical enthesitis in psoriasis (PsO) patients in different countries ranges between 7% and 20% [2].

Objectives:

The main objective of this study was to estimate, by US evaluation, the prevalence of subclinical enthesitis in PsO patients without any clinical signs of enthesitis. Secondary objectives were to analyze differences, in terms of age, sex, BMI, PsO onset and diagnosis, among patients with enthesitis (active or not active), enthesopathy and without any alteration of enthesis.

According to the OMERACT definition of ultrasound enthesitis, patients were divided into 4 groups: patients with active enthesitis (AE) defined as the presence of power-Doppler signal in a hypoechoic and/or thickened insertion of the tendon close to the bone; patient with enthesitis (En) defined as hypoechoic and/or thickened insertion of the tendon close to the bone without PD signal; patients with enthesopathy (Ep) defined as the presence of structural damage (erosions, enthesophytes/calcifications); patients without any alteration of enthesis (WE).

Methods:

Patients with at least 18 years and a diagnosis of PsO made by a Dermatologist were included. Exclusion criteria were the presence of clinical symptoms or signs of articular or entheseal involvement, diagnosis of arthritis and therapy with bDMARDs or tsDMARDs.

All patients underwent US examination on grey scale and Power Doppler (PD) ultrasonography of 6 sites (Achilles, quadriceps, distal and proximal patellar, plantar fascia and triceps enthesis) bilaterally. Ultrasound was performed by an experienced sonographer, using a Logiq P9 equipped with 6-12 MHz broad band linear transducer. Data were reported as frequencies and median with interquartile range. To check differences among these four groups, we used chi-square test or Kruskall-Wallis test. P-value ≤ 0.05 is considered statistically significant.

Results:

We enrolled 124 consecutive psoriasis patients (47 [37.9%] female) with median age 57.7 (45.3-66.5) years, median disease duration 20.4 (10.1-30.8) years, median BMI 27 [24-29]. Patients with AE, En, Ep were 20.2% (25/124), 49.2% (61/124) and 18.5% (23/124), respectively.

Patients WE (12.1%, 15/124) showed significantly lower BMI, younger age and shorter diagnostic delay compared to the other patients.

All signs of enthesopathy/enthesitis were more frequently observed at Achilles (33.1%, 41/124), triceps (23.4%, 29/124), quadriceps (20.2%, 25/124), distal patellar (18.5%, 23/124) and proximal patellar (4.8%, 6/124) enthesis.

Conclusion:

Subclinical enthesitis is quite common in PsO patients, and about 20% showed active enthesitis. The enthesopathy seems to be more frequent in patients with increased delay in PsO diagnosis, older age and higher BMI.

References:

[1]Bandinelli F. et al. Ultrasound detects occult entheseal involvement in early psoriatic arthritis independently of clinical features and psoriasis severity. Clin Exp Rheumatology. Mar-Apr 2013;31(2):219-24.

[2]Zuliani F. et al. Ultrasonographic detection of subclinical enthesitis and synovitis: a possible stratification of psoriatic patients without clinical musculoskeletal involvement. Clin Exp Rheumatol Jul-Aug 2019;37(4):593-599.

[3]Balint P. V. et al. Reliability of a consensus-based ultrasound definition and scoring for enthesitis in spondyloarthritis and psoriatic arthritis: an OMERACT US initiative. Ann Rheum Dis 2018 Dec;77(12):1730-1735.

Disclosure of Interests:

None declared.

Radiotherapy, Temozolomide, and Antiprogrammed Cell Death Protein 1 Treatments Modulate the Immune Microenvironment in Experimental High-Grade Glioma

BACKGROUND

The lack of immune synergy with conventional chemoradiation could explain the failure of checkpoint inhibitors in current clinical trials for high-grade gliomas (HGGs).

OBJECTIVE

To analyze the impact of radiotherapy (RT), Temozolomide (TMZ) and antiprogrammed cell death protein 1 (αPD1) (as single or combined treatments) on the immune microenvironment of experimental HGGs.

METHODS

Mice harboring neurosphere /CT-2A HGGs received RT (4 Gy, single dose), TMZ (50 mg/kg, 4 doses) and αPD1 (100 μg, 3 doses) as monotherapies or combinations. The influence on survival, tumor volume, and tumor-infiltrating immune cells was analyzed.

RESULTS

RT increased total T cells (P = .0159) and cluster of differentiation (CD)8+ T cells (P = .0078) compared to TMZ. Lymphocyte subpopulations resulting from TMZ or αPD1 treatment were comparable with those of controls. RT reduced M2 tumor-associated macrophages/microglia (P = .0019) and monocytic myeloid derived suppressor cells (mMDSCs, P = .0003) compared to controls. The effect on mMDSC was also seen following TMZ and αPD1 treatment, although less pronounced (P = .0439 and P = .0538, respectively). Combining RT with TMZ reduced CD8+ T cells (P = .0145) compared to RT alone. Adding αPD1 partially mitigated this effect as shown by the increased CD8+ T cells/Tregs ratio, even if this result failed to reach statistical significance (P = .0973). Changing the combination sequence of RT, TMZ, and αPD1 did not alter survival nor the immune effects.

CONCLUSION

RT, TMZ, and αPD1 modify the immune microenvironment of HGG. The combination of RT with TMZ induces a strong immune suppression which cannot be effectively counteracted by αPD1.

Free-hand stereotactic ventricular catheter insertion technique based on radio-anatomical landmarks. How I do it

BACKGROUND

Accurate ventricular catheter (VC) placement plays an important role in reducing the risk of ventriculoperitoneal shunt failure. Free-hand VC insertion is associated with a significant misplacement rate. Consequently, several expensive alternative methods that are unfortunately not available worldwide have been used. To overcome these limitations, we developed a simple surgical technique based on radio-anatomical landmarks aimed at reducing VC's misplacements.

METHOD

We reproduce the preoperative imaging on the patient's head using common anatomical landmarks. This allows defining stereotactic VC coordinates to be followed during the surgical procedure.

CONCLUSION

This simple and cost-effective method improves VC insertion accuracy.

Decrease in sulfate aerosol light backscattering by reactive uptake of isoprene epoxydiols

Sulfate aerosol is responsible for a net cooling of the Earth's atmosphere due to its ability to backscatter light. Through atmospheric multiphase chemistry, it reacts with isoprene epoxydiols leading to the formation of aerosol and organic compounds, including organosulfates and high-molecular weight compounds. In this study, we evaluate how sulfate aerosol light backscattering is modified in the presence of such organic compounds. Our laboratory experiments show that reactive uptake of isoprene epoxydiols on sulfate aerosol is responsible for a decrease in light backscattering compared to pure inorganic sulfate particles of up to - 12% at 355 nm wavelength and - 21% at 532 nm wavelength. Moreover, while such chemistry is known to yield a core-shell structure, the observed reduction in the backscattered light intensity is discussed with Mie core-shell light backscattering numerical simulations. We showed that the observed decrease can only be explained by considering effects from the complex optical refractive index. Since isoprene is the most abundant hydrocarbon emitted into the atmosphere, and isoprene epoxydiols are the most important isoprene secondary organic aerosol precursors, our laboratory findings can aid in quantifying the direct radiative forcing of sulfates in the presence of organic compounds, thus more clearly resolving the impact of such aerosol particles on the Earth's climate.

How I do it: anterior interhemispheric approach to tuberculum sellae meningiomas

BACKGROUND

Tuberculum sellae meningiomas are deep-seated tumors difficult to access, located in close relation with important neurovascular structures. While the transsphenoidal approach is linked to specific complications, the different reported transcranial approaches are associated with advantages and drawbacks due to the respective angle of attack, with some areas adequately exposed and others partially hidden.

METHOD

We report the technical aspects of the anterior interhemispheric approach we practice.

CONCLUSION

This approach has the advantage of providing full control over all the vasculo-nervous structures involved and of allowing access to the medial aspect of both optic canals tangentially to the dorsum sellae.

Bringing the Ca2+ sensitivity of myristoylated recoverin into the physiological range

The prototypical Ca²⁺-sensor protein recoverin (Rec) is thought to regulate the activity of rhodopsin kinase (GRK1) in photoreceptors by switching from a relaxed (R) disc membrane-bound conformation in the dark to a more compact, cytosol-diffusing tense (T) conformation upon cell illumination. However, the apparent affinity for Ca²⁺ of its physiologically relevant form (myristoylated recoverin) is almost two orders of magnitude too low to support this mechanism in vivo. In this work, we compared the individual and synergistic roles of the myristic moiety, the GRK1 target and the disc membrane in modulating the calcium sensitivity of Rec. We show that the sole presence of the target or the disc membrane alone are not sufficient to achieve a physiological response to changes in intracellular [Ca²⁺]. Instead, the simultaneous presence of GRK1 and membrane allows the T to R transition to occur in a physiological range of [Ca²⁺] with high cooperativity via a conformational selection mechanism that drives the structural transitions of Rec in the presence of multiple ligands. Our conclusions may apply to other sensory transduction systems involving protein complexes and biological membranes.

Deciphering the pathogenesis of the COL4-related hematuric nephritis: A genotype/phenotype study

Background

Alport syndrome (ATS) is a hereditary progressive hematuric nephropathy associated with sensorineural deafness and ocular abnormalities, which is caused by mutations in the COL4A5 gene (X‐linked ATS) and in two autosomal genes, COL4A4 and COL4A3, responsible of both recessive ATS and, when present in heterozygosity, of a spectrum of phenotypes ranging from isolated hematuria to frank renal disease.

Methods

Retrospective analysis of the clinical and genetic features of 76 patients from 34 unrelated ATS families (11 with mutations in COL4A5, 11 in COL4A3, and 12 in COL4A4) and genotype/phenotype correlation for the COL4A3/COL4A4 heterozygotes (34 patients from 14 families).

Results

Eight (24%) of the 34 heterozygous COL4A3 and COL4A4 carriers developed renal failure at a mean age of 57 years, with a significantly lower risk than hemizygous COL4A5 or double heterozygous COL4A3/COL4A4 carriers (p < 0.01), but not different from that of the heterozygous COL4A5 females (p = 0.6). Heterozygous carriers of frameshift/splicing variants in COL4A3/COL4A4 presented a higher risk of developing renal failure than those with missense variants in the glycine domains (p = 0.015).

Conclusion

The renal functional prognosis of patients with COL4A3/COL4A4‐positive ATS recapitulates that of the X‐linked ATS forms, with differences between heterozygous vs. double heterozygous patients and between carriers of loss‐of‐function vs. missense variants.

Immunocompetent Mouse Models in the Search for Effective Immunotherapy in Glioblastoma

Glioblastoma (GBM) is the most aggressive intrinsic brain tumor in adults. Despite maximal therapy consisting of surgery and radio/chemotherapy, GBM remains largely incurable with a median survival of less than 15 months. GBM has a strong immunosuppressive nature with a multitude of tumor and microenvironment (TME) derived factors that prohibit an effective immune response. To date, all clinical trials failed to provide lasting clinical efficacy, despite the relatively high success rates of preclinical studies to show effectivity of immunotherapy. Various factors may explain this discrepancy, including the inability of a single mouse model to fully recapitulate the complexity and heterogeneity of GBM. It is therefore critical to understand the features and limitations of each model, which should probably be combined to grab the full spectrum of the disease. In this review, we summarize the available knowledge concerning immune composition, stem cell characteristics and response to standard-of-care and immunotherapeutics for the most commonly available immunocompetent mouse models of GBM.

Head down tilt 15° in experimental intracerebral hemorrhage: a randomized noninferiority safety trial

BACKGROUND AND PURPOSE

Head down tilt 15° (HDT15°), applied before recanalization, increases collateral flow and improves outcome in experimental ischemic stroke. For its simplicity and low cost, HDT15° holds considerable potential to be developed as an emergency treatment of acute stroke in the prehospital setting, where hemorrhagic stroke is the major mimic of ischemic stroke. In this study, we assessed safety of HDT15° in the acute phase of experimental intracerebral hemorrhage.

METHODS

Intracerebral hemorrhage was produced by stereotaxic injection of collagenase in Wistar rats. A randomized noninferiority trial design was used to assign rats to HDT15° or flat position (n = 64). HDT15° was applied for 1 h during the time window of hematoma expansion. The primary outcome was hematoma volume at 24 h. Secondary outcomes were mass effect, mortality, and functional deficit in the main study and acute changes of intracranial pressure, hematoma growth, and cardiorespiratory parameters in separate sets of randomized animals (n = 32).

RESULTS

HDT15° achieved the specified criteria of noninferiority for hematoma volume at 24 h. Mass effect, mortality, and functional deficit at 24 h showed no difference in the two groups. HDT15° induced a mild increase in intracranial pressure with respect to the pretreatment values (+2.91 ± 1.76 mmHg). HDT15° had a neutral effect on MRI-based analysis of hematoma growth and cardiorespiratory parameters.

CONCLUSIONS

Application of HDT15° in the hyperacute phase of experimental intracerebral hemorrhage does not worsen early outcome. Further research is needed to implement HDT15° as an emergency collateral therapeutic for acute stroke.

The Pathway Study: Commonalities Across New Food Bank Users in Rural, Suburban and Urban Areas

Background

Few studies investigate long-term effects of food donation programs on food insecurity, diet, social integration or health. We describe household food insecurity (HFI), health, social integration and sociodemographic characteristics of 1003 new food banks users in rural, suburban and urban areas in Quebec, Canada.

Methods

Adults requesting food aid for the first time in the past 6 months were recruited in 117 food aid organizations (32 in rural, 35 in suburban, 50 in urban areas) using a nested sampling technique. Baseline data were collected from Sept 2018 to Jan 2020 in computer-assisted face-to-face interviews. Participants will be followed biennially. HFI was assessed with the 18-item Household Food Security Survey Module. Perceived physical and mental health scores were assessed with the SF12V2 module. Psychological distress and social integration were assessed with the Kessler scale K6+ and a modified version of MSPSS Scale. Differences across groups were tested with Chi square, ANOVA and post-hoc tests.

Results

Most participants reported high levels of materiel deprivation, with some variability across settings. Severe HFI was more prevalent in rural (51%) and urban (47%) areas than in suburbs (38%). More urban participants reported &lt;20000 CAN$/yr (79% vs 74% in suburbs and 69% in rural) although low education level was more prevalent in rural areas (82% reported &lt;12th grade education vs. 67% in suburban and 64% in urban areas). Psychological distress was higher in the suburbs (28%) compared to urban (21%) or rural areas (22%). No differences were detected across settings in social integration or physical or mental health scores.

Conclusions

New users of food banks report markedly high levels of material, social and health-related deprivation. In-depth analyses will permit more meaningful interpretation of these differences. The Pathways Study will permit better understanding of the life experience of persons requesting food assistance.

Key messages

People demanding food aid for the first time reported high levels of materiel deprivation, with some variability across settings. Severe housefold insecurity is around 50% among new food aid demanders in rural and urban settings.

Clinical, radiological and molecular characterization of intramedullary astrocytomas

Intramedullary astrocytomas (IMAs) are rare tumors, and few studies specific to the molecular alterations of IMAs have been performed. Recently, KIAA1549-BRAF fusions and the H3F3A p.K27M mutation have been described in low-grade (LG) and high-grade (HG) IMAs, respectively. In the present study, we collected clinico-radiological data and performed targeted next-generation sequencing for 61 IMAs (26 grade I pilocytic, 17 grade II diffuse, 3 LG, 3 grade III and 12 grade IV) to identify KIAA1549-BRAF fusions and mutations in 33 genes commonly implicated in gliomas and the 1p/19q regions. One hundred seventeen brain astrocytomas were analyzed for comparison. While we did not observe a difference in clinico-radiological features between LG and HG IMAs, we observed significantly different overall survival (OS) and event-free survival (EFS). Multivariate analysis showed that the tumor grade was associated with better OS while EFS was strongly impacted by tumor grade and surgery, with higher rates of disease progression in cases in which only biopsy could be performed. For LG IMAs, EFS was only impacted by surgery and not by grade. The most common mutations found in IMAs involved TP53, H3F3A p.K27M and ATRX. As in the brain, grade I pilocytic IMAs frequently harbored KIAA1549-BRAF fusions but with different fusion types. Non-canonical IDH mutations were observed in only 2 grade II diffuse IMAs. No EGFR or TERT promoter alterations were found in IDH wild-type grade II diffuse IMAs. These latter tumors seem to have a good prognosis, and only 2 cases underwent anaplastic evolution. All of the HG IMAs presented at least one molecular alteration, with the most frequent one being the H3F3A p.K27M mutation. The H3F3A p.K27M mutation showed significant associations with OS and EFS after multivariate analysis. This study emphasizes that IMAs have distinct clinico-radiological, natural evolution and molecular landscapes from brain astrocytomas.

AB0316 MULTIPLE SWITCH BETWEEN BIOSIMILARS DMARDs (BSDMARDS) IN PATIENTS WITH INFLAMMATORY ARTHRITIDES: EXPERIENCE OF A SINGLE ITALIAN CENTRE

Background:

The availability of bsDMARDs since some years represents an opportunity to improve patient access to effective biologic therapy, to better accommodate restraints within healthcare budgets and to improve overall patient outcomes. Different policies are followed in different countries to implement the use of bsDMARDs. Although the latest position paper of AIFA (Agenzia Italiana del Farmaco) envisions the automatic sostitution between the originator and biosimilar, until now the prescriber decision and the patient consent are strongly advised. The question around biosimilar to biosimilar switching is overlooked. Nevertheless different rules are established at regional level and in our Hospital automatic switching between originator/biosimilar and biosimilar/biosimilar was applied.

Objectives:

To analyze the efficacy and safety of switch from originator to biosimilar (O/B) and/or biosimilar to biosimilar (B/B) in patients with RA, PsA and SpA.

Methods:

We retrospectively analyzed in 63 patients (30 F, mean age 58.3 yr, 21 RA, 26 PsA, 16 SpA), treated with Infliximab, Etanercept and Adalimumab, disease activity (DAS28 CRP for RA, Tender/Swollen joint count for PsA, BASDAI for SpA, CRP for all) and adverse events/infections (AE). The time points considered were 3rdmonth before the switch and 3rdand 6thmonth after.

Results:

45 patients underwent sigle switch (35 O/B, 9 B/B) and 18 (28.5%) double switch (O/B/B). 27 B/B switch were done. No differences in disease activity were observed before and after switch (8 RA patients: mDAS28 CRP 2.86>3.23, 11 PsA patients: mTJ count 2.5 > 3.43, 8 SpA patients: BASDAI 2.88 > 2.84). The mean number of swollen joints was very low in PsA group and we decided to exclude this variable. The CRP level was low and stable along all period examined in the three groups. No increase in steroid daily dose, nor in concomitant DMARDs therapy was reported. In the Etanercept B/B switch (14 pts) the number of infections was the same before (3) and after (3). In Infliximab B/B switch (13 pts) 3 infections were reported only before the switch. The severity was mild/moderate with prevalence of respiratory infections (57%). No remarkable variation of transaminases and blood counts were observed.

Conclusion:

Althoug the population we examined was eterogeneous and quite small, we observed that the efficay and safety of Infliximab and Etanercept are maintained with biosimilar to biosimilar switch, also after double switch (originator>biosimilar>biosimilar). We also can confirm that the switch from originator to biosimilar Infliximab, Etanercept and Adalimumab is safe in our experience.

Disclosure of Interests:

None declared

THU0616-HPR EXPIRATORY FLOW ACCELERATOR (EFA) IN SYSTEMIC SCLEROSIS PATIENTS WITH MUCUS HYPERSECRETION, PRODUCTIVE COUGH AND DYSPNOEA: PRELIMINARY RESULTS FROM A HOME-BASED AIRWAY CLEARANCE TECHNIQUE DAILY PROGRAM

Background:

Systemic sclerosis (SSc) is a chronic disease with frequent lung involvement. As mucociliary clearance is impaired, mucus retention and frequent pulmonary infections, increase morbidity and mortality (1).

Airway clearance techniques (ACT) enhance removal of mucus from the airways. Expiratory flow accelerator (EFA) is a new technology that promotes deep and gentle drainage of the bronchial secretions, through the Venturi effect. No respiratory effort is required and no negative pressure is generated, avoiding risk of bronchial collapse (2).

Objectives:

The aim of this study was to describe the effectiveness of EFA in improving pulmonary symptoms in SSc patients.

Methods:

SSc patients with daily productive cough, frequent pulmonary exacerbations, exertional dyspnea and/or reduced physical activity were selected. All of them underwent a home-based ACT program with EFA. A Respiratory Physiotherapist (RT) trained each patient to use the device 3 times a day, 15 minutes each session. Every subject compiled the Saint George’s Respiratory Questionnaire (SGRQ) and scleroderma Health Assessment Questionnaire (SHAQ) at baseline, 30, 90 and 180 days from the beginning. Statistical analysis has been carried out with General linear model for repeated measures. A value of p<0.05 was considered statistically significant.

Results:

8 patients were enrolled (M:F=1:7), median age 54 (IC95% 46-69) years. Interstitial lung disease affected the majority of them (7/8). SGRQ total score and SHAQ domain for respiratory symptoms decreased over time (p= 0.003 and p= 0.005). In particular, there was an improvement in two SGRQ domains: activities (p= 0.013) and symptoms (p= 0.005) (fig.1).

Figure 1

Conclusion:

This is the first study to investigate the effect of EFA technology on airway clearance in SSc patients. The observations suggest the importance of a daily ACT program with EFA in improving respiratory symptoms. This technology appear to be extremely promising in SS patient management as it is well tolerated and it has the potential to slow down the pulmonary disease progression by limiting bronchial infections.

References:

[1]Tyndall AJ et al. Causes and risk factors for death in systemic sclerosis: a study from the EULAR Scleroderma Trials and Research (EUSTAR) database. Ann Rheum Dis 2010;69:1809–15.

[2]Zampogna E, et al. Expiratory Flow Accelerator (EFA) technique on mucus hypersecretion of COPD patients with reduced cough efficiency after a severe exacerbation. Int Clin Med 2019;3:1-6.

Disclosure of Interests:

Silvia faverzani: None declared, Andrea Becciolini Speakers bureau: Sanofi-Genzyme, UCB and AbbVie, ernesto crisafulli: None declared, filippo nocera: None declared, eleonora di donato: None declared, Flavio Mozzani: None declared, michele riva: None declared, Daniele Santilli: None declared, lorenza monica: None declared, annalisa barbieri: None declared, lissette barone: None declared, maurizio marvisi: None declared, veronica alfieri: None declared, annalisa frizzelli: None declared, Alfredo Chetta: None declared, ALARICO ARIANI: None declared

Long-lived tumor-associated macrophages in glioma

BACKGROUND

The tumor microenvironment plays a major tumor-supportive role in glioma. In particular, tumor-associated macrophages (TAMs), which can make up to one-third of the tumor mass, actively support tumor growth, invasion, and angiogenesis. Predominantly alternatively activated (M2-polarized) TAMs are found in late-stage glioma in both human and mouse tumors, as well as in relapse samples from patients. However, whether tumor-educated M2 TAMs can actively contribute to the emergence and growth of relapse is currently debated.

METHODS

To investigate whether tumor-educated stromal cells remaining in the brain after surgical removal of the primary tumor can be long-lived and retain their tumor-supporting function, we developed a transplantation mouse model and performed lineage-tracing.

RESULTS

We discovered that macrophages can survive transplantation and stay present in the tumor much longer than previously suggested, while sustaining an M2-polarized protumorigenic phenotype. Transplanted tumors showed a more aggressive growth and faster polarization of the TAMs toward an M2 phenotype compared with primary tumors, a process dependent on the presence of few cotransplanted macrophages.

CONCLUSIONS

Overall, we propose a new way for tumor-educated TAMs to contribute to glioma aggressiveness by long survival and stable protumorigenic features. These properties could have a relapse-supporting effect.

CT-2A neurospheres-derived high-grade glioma in mice: a new model to address tumor stem cells and immunosuppression

Recently, several promising treatments for high-grade gliomas (HGGs) failed to provide significant benefit when translated from the preclinical setting to patients. Improving the animal models is fundamental to overcoming this translational gap. To address this need, we developed and comprehensively characterized a new in vivo model based on the orthotopic implantation of CT-2A cells cultured in neurospheres (NS/CT-2A). Murine CT-2A methylcholanthrene-induced HGG cells (C57BL/6 background) were cultured in monolayers (ML) or NS and orthotopically inoculated in syngeneic animals. ML/CT-2A and NS/CT-2A tumors' characterization included the analysis of tumor growth, immune microenvironment, glioma stem cells (GSCs), vascularization and metabolites. The immuno-modulating properties of NS/CT-2A and ML/CT-2A cells on splenocytes were tested in vitro. Mice harboring NS/CT-2A tumors had a shorter survival than those harboring ML/CT-2A tumors (P=0.0033). Compared to standard ML/CT-2A tumors, NS/CT-2A tumors showed more abundant GSCs (P=0.0002 and 0.0770 for Nestin and CD133, respectively) and regulatory T cells (Tregs, P=0.0074), and a strong tendency towards an increased vascularization (P=0.0503). There were no significant differences in metabolites' composition between NS/ and ML/CT-2A tumors. In vitro, NS were able to drive splenocytes towards a more immunosuppressive status by reducing CD8⁺ T cells (P=0.0354) and by promoting Tregs (P=0.0082), macrophages (MF, P=0.0019) and their M2 subset (P=0.0536). Compared to standard ML/CT-2A tumors, NS/CT-2A tumors show a more aggressive phenotype with increased immunosuppression and GSCs proliferation. Because of these specific features, the NS/CT-2A model represents a clinically relevant platform in the search for new HGG treatments aimed at reducing immunosuppression and eliminating GSCs.

Summary: The NS/CT-2A tumor model represents a valuable research platform for the study of innovative treatments aimed at eliminating GSCs and reversing the tumor-induced immunosuppression in HGGs.

Myeloid Derived Suppressor Cells: Key Drivers of Immunosuppression in Ovarian Cancer

The presence of tumor infiltrating lymphocytes (TILs) is associated with a longer overall survival in advanced stage epithelial ovarian cancer. Despite the prognostic impact of TILs, response to checkpoint-inhibitors and antigen-specific active immunotherapy is limited in ovarian cancer. The goal of our study was to investigate the interaction between ovarian cancer and the innate and adaptive immune system in the ID8-fLuc syngeneic ovarian cancer mouse model. For the in vivo experiments C57BL/6, B6.129S7-Rag1^tm1Mom/J, and B6.129P2(SJL)-Myd88^tm1.1Defr/J mice were inoculated with ID8-fLuc. In vivo depletion experiments were performed using clodronate liposomes (CL), anti-CD8a, anti-GR1, anti-colony stimulating factor 1 (anti-CSF1), and TMβ1 (anti-CD122). Immune read out was performed by fluorescent activated cell sorting analysis for effector T cells, regulatory T cells, natural killer cells, B cells, macrophages, and myeloid derived suppressor cells (MDSC), immunohistochemistry for MDSC and tumor-associated macrophages (TAM) and immunofluorescence for M1 and M2 TAM in the vascular context. The effect of MDSC on T cell proliferation and phenotype were studied in vitro. We discovered that the absence of T and B cells did not influence tumor growth or survival of B6.129S7-Rag1^tm1Mom/J mice compared to immunocompetent C57BL/6 mice. CL-induced macrophage depletion promoted tumor proliferation and shortened survival in C57BL/6 mice (p = 0.004) and in B6.129S7-Rag1^tm1Mom/J mice (p = 0.0005). During CL treatment, we observed a clear increase of pro-inflammatory cytokines (p ≤ 0.02) and monocytic MDSC (p ≤ 0.01). Selective depletion of MDSC by anti-GR1 improved survival, certainly in comparison to mice treated with anti-CSF1 (p = 0.01-median survival 91 vs. 67.5 days). B6.129P2(SJL)-Myd88^tm1.1Defr/J mice displayed to a longer median survival compared to C57BL/6 mice (90 vs. 76 days). MDSC activated by ID8-fLuc conditioned medium or ascites of tumor-bearing mice showed T cell suppressive functions in vitro. Based on these findings, we conclude that the adaptive immune system does not efficiently control tumor growth in the ID8-fLuc model. In addition, we discovered a prominent role for MDSC as the driver of immunosuppression in the ID8-fLuc ovarian cancer mouse model.

RPC10 encodes a new mini subunit shared by yeast nuclear RNA polymerases

Yeast RNA polymerases A, B, and C share five small subunits, two of which, ABC10 alpha and ABC10 beta, comigrate on SDS polyacrylamide gels. The gene encoding ABC10 alpha, RPC10, was isolated based on microsequence data. RPC10 is a single copy gene localized on chromosome VIII. It codes for a very basic protein of only 70 amino acids, which contains a zinc binding domain of the form CX2CX13CX2C. Deletion of its gene indicated that, despite its very small size, the ABC10 alpha subunit is essential for yeast cell viability. ABC10 alpha and ABC10 beta have little sequence similarity.

Abstract 1769: Antibody blockade of IL1RAP signaling reduces metastasis in a breast cancer model

Blockade of tumor inflammation has potential for cancer therapy, both as a primary mechanism to counter tumor growth but also in combination with other therapeutics. IL-1 signaling has been shown preclinically to be involved in tumor development and chemoresistance of pancreatic cancer, and blockade of IL-1 was recently shown to have a significant clinical impact on development of lung cancer. IL-1 receptor associated protein (IL1RAP) is a coreceptor for the IL-1 receptor (IL1R1) and is required for IL-1 signaling. IL1RAP is expressed in a number of tumor tissues, including lung and pancreatic cancer, both on tumor cells and on infiltrating immune cells. We have, using antibodies directed against IL1RAP, shown the ability to target and kill IL1RAP-expressing tumor cells by ADCC, to inhibit IL-1 signaling in those cells and to reduce growth of transplanted human tumors in vivo. To study effects of IL1RAP targeting on the tumor microenvironment and in an immune competent setting, an antibody towards mouse IL1RAP was generated. This antibody potently blocks mouse IL-1 (IC50 = 13 nM), binds to IL1RAP protein with high affinity (Kd = 4,2 nM), labels IL1RAP-expressing cells and can be administered to mice with good pharmacokinetics. In vivo imaging shows that the antibody is not generally distributed in tissues but localizes to tumor sites after injection. Treatment of mice with orthotopically implanted 4T1 breast cancer cells did not reduce primary tumor growth significantly but reduced both the number of (47% reduction, p=0.02) and size of lung metastases. Interestingly, 4T1 tumor cells express low levels of IL1RAP and are not responsive to IL1RAP blockade, but the effects instead relate to effects on the tumor microenvironment. We conclude that targeting of IL1RAP can, in addition to induce ADCC of tumor cells and block their response to IL-1, also inhibit metastasis by affecting the tumor microenvironment.

Citation Format: David Liberg, Per-Ola Önnervik, Matteo Riva, Liselotte Larsson, Göran Forsberg, Karin von Wachenfeldt. Antibody blockade of IL1RAP signaling reduces metastasis in a breast cancer model [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 1769.

Intracerebral hemorrhage in Intensive Care Unit: early prognostication fallacies. A single center retrospective study

BACKGROUND

Intracerebral hemorrhage (ICH) admitted to Intensive Care is deem of poor prognosis. The aim of this study was to compare observed and predicted 30-day mortality and to evaluate long term functional outcome in a consecutive ICH cohort.

METHODS

Retrospective analysis of prospectively collected data of ICH patients managed in a Neuro-ICU from 2012 to 2015.

RESULTS

Out of 136 consecutive patients, 34 (25%) had "withholding of life-sustaining treatment" (WLST) order and 102 (75%) received a "full treatment" (FT). WLST cohort: median (IQR): 72 (70-77) years old, Glasgow Coma Scale (GCS) 4 (3-4) at admission, ICH volume 114 cm3 (68-152); all patients died during neuro-ICU recovery, 28 (82%) patients had brain death diagnosis and 15 (54%) of these were organ donors. FT cohort: 67 (51-73) years old, GCS 9 (6-12) at admission, ICH volume 46 (24-90) cm3, neurosurgery for clot removal in 65 (64%) (P<0.05 vs. WLST cohort for each of previously listed variables); 13 (13%) patients died during neuro-ICU recovery, of these 11 (85%) patients had brain death diagnosis and 4 (36%) of them were organ donors. Overall 30-day observed mortality for FT group was 18% (95% CI: 11-26%). Patients with ICH Score 1, 2, 3, 4+ had 0%, 10%, 16% and 26% 30-day mortality, respectively (P<0.01 vs. ICH Score). Full treatment group 180-day mortality was 32% (95% CI: 24-42%). Modified Rankin Scale (mRS) after one year was ≤3 in 35 (35%), i.e. good recovery, and >3 in 64 (65%). Neurosurgery for clot removal was associated with a lower 30 and 180-day mortality (P=0.01 and P=0.03, respectively) and along with GCS at admission it was an independent significant prognostic factor.

CONCLUSIONS

Mortality and functional outcome is less severe than predicted in patients with ICH receiving a full medical and/or surgical treatment.

Cerebral collateral therapeutics in acute ischemic stroke: A randomized preclinical trial of four modulation strategies

Cerebral collaterals are dynamically recruited after arterial occlusion and highly affect tissue outcome in acute ischemic stroke. We investigated the efficacy and safety of four pathophysiologically distinct strategies for acute modulation of collateral flow (collateral therapeutics) in the rat stroke model of transient middle cerebral artery (MCA) occlusion. A composed randomization design was used to assign rats (n = 118) to receive phenylephrine (induced hypertension), polygeline (intravascular volume load), acetazolamide (cerebral arteriolar vasodilation), head down tilt (HDT) 15° (cerebral blood flow diversion), or no treatment, starting 30 min after MCA occlusion. Compared to untreated animals, treatment with collateral therapeutics was associated with lower infarct volumes (62% relative mean difference; 51.57 mm³ absolute mean difference; p < 0.001) and higher chance of good functional outcome (OR 4.58, p < 0.001). Collateral therapeutics acutely increased cerebral perfusion in the medial (+40.8%; p < 0.001) and lateral (+19.2%; p = 0.016) MCA territory compared to pretreatment during MCA occlusion. Safety indicators were treatment-related mortality and cardiorespiratory effects. The highest efficacy and safety profile was observed for HDT. Our findings suggest that acute modulation of cerebral collaterals is feasible and provides a tissue-saving effect in the hyperacute phase of ischemic stroke prior to recanalization therapy.

Indocyanine Green Videoangiography in Aneurysm Surgery: Systematic Review and Meta-Analysis

BACKGROUND

Although digital subtraction angiography (DSA) may be considered the gold standard for intraoperative vascular imaging, many neurosurgical centers rely only on indocyanine green videoangiography (ICG-VA) for the evaluation of clipping accuracy. Many studies have compared the results of ICG-VA with those of intraoperative DSA; however, a systematic review summarizing these results is still lacking.

OBJECTIVE

To analyze the literature in order to evaluate ICG-VA accuracy in the identification of aneurysm remnants and vessel stenosis after aneurysm clipping.

METHODS

We performed a systematic literature review of ICG-VA accuracy during aneurysm clipping as compared to microscopic visual observation (primary endpoint 1) and DSA (primary endpoint 2). Quality of studies was assessed with the QUADAS-2 tool. Meta-analysis was performed using a random effects model.

RESULTS

The initial PubMed search resulted in 2871 records from January 2003 to April 2016; of these, 20 articles were eligible for primary endpoint 1 and 11 for primary endpoint 2. The rate of mis-clippings that eluded microscopic visual observation and were identified at ICG-VA was 6.1% (95% CI: 4.2-8.2), and the rate of mis-clippings that eluded ICG-VA and were identified at DSA was 4.5% (95% CI: 1.8-8.3).

CONCLUSION

Because a proportion of mis-clippings cannot be identified with ICG-VA, this technique should still be considered complementary rather than a replacement to DSA during aneurysm surgery. Incorporating other intraoperative tools, such as flowmetry or electrophysiological monitoring, can obviate the need for intraoperative DSA for the identification of vessel stenosis. Nevertheless, DSA likely remains the best tool for the detection of aneurysm remnants.