The Impact of TP53 Mutations and Use of the TP53-Mutation-Reactivating Agent APR-246 on Metastatic Castrate-Sensitive Prostate Cancer

PURPOSE/OBJECTIVE(S)

TP53 mutations appear to be enriched over the spectrum of metastatic castration-sensitive prostate cancer (mCSPC) and are associated with worse survival outcomes. We chose to further explore the impact of dominant negative (DN) TP53 mutations on mCSPC progression and pro-metastatic behaviors in addition to studying the ability of APR-246, a small molecule targeting TP53 mutants, to blunt pro-metastatic behaviors.

MATERIALS/METHODS

We retrospectively analyzed 531 mCSPC patients who underwent next-generation sequencing. Patients were stratified by metastasis timing (synchronous if metastasis present at diagnosis or metachronous if arising after definitive treatment of localized disease) and the number of metastatic lesions (oligometastatic ≤5 or polymetastatic >5 lesions). Tumors were classified based on TP53 mutation status (missense, truncating, or wild-type [WT]) and dominant negativity, which was defined as the production of a mutant protein that reduces the residual WT protein's transcriptional activity according to the World Health Organization TP53 database. Clinical outcomes were radiographic progression-free survival (rPFS) and overall survival (OS), evaluated with Kaplan-Meier and multivariable Cox regression. To verify the impact of TP53 mutation on metastasis, we created isogenic 22Rv1 prostate cancer cell lines that carried either TP53 WT or TP53 R175H and tested this mutation for migration, invasion, and anchorage-independent growth. APR-246 (25-80 µM) was tested for anti-metastatic properties in vitro and anti-tumor growth in 22Rv1 xenografted nude mice.

RESULTS

In our cohort, 155 (29.2%) had a TP53 mutation, which mostly occurred in the DNA-binding domain (85.16%). DN TP53 mutations were associated with more aggressive disease states: DN TP53 mutations were enriched in patients with synchronous (vs. metachronous: 20.7% vs. 6.3%, p < 0.01) and polymetastatic disease (vs. oligometastatic: 14.4% vs. 7.9%, p < 0.01). On multivariable analysis, DN TP53 mutations were correlated with shorter rPFS (HR = 1.97, 95% CI: 1.31-2.98, p < 0.01) and OS (HR = 2.05, 95% CI: 1.14-3.68, p = 0.02) compared to those with TP53 WT. In vitro, 22Rv1 cells with DN TP53 R175H mutation had increased abilities to migrate, invade, and form colonies compared to TP53 WT. APR-246 treatment of TP53 R175H mutants blunted the pro-metastatic effects of the cell line in vitro (p < 0.01 for all assays by unpaired t-test). Interestingly, APR-246 also inhibited xenograft tumor growth of 22Rv1 TP53 R175H mutants (p < 0.0001 by two-way ANOVA).

CONCLUSION

DN TP53 mutations were associated with poorer survival outcomes for mCSPC patients. DN TP53 mutations also promoted prostate cancer pro-metastatic behaviors in vitro, which was effectively counteracted by APR-246, making it a promising treatment option that should be explored further in early-phase clinical studies.

Identification of a Predictive Genomic Biomarker for Prostate Directed Therapy in Synchronous Low-Volume Metastatic Castration Sensitive Prostate Cancer

PURPOSE/OBJECTIVE(S)

Standard of care management for metastatic castration sensitive prostate cancer (mCSPC) includes androgen deprivation therapy (ADT) with docetaxel or second-generation anti-androgen therapy. Recently, randomized data has demonstrated radiotherapy to the prostate is associated with an improvement in overall survival among patients with low-volume metastatic disease. Tumor genomics represents an additional dimension to understand the clinical trajectory of patients with mCSPC. Herein we aim to evaluate a high-risk genomic signature for its ability to predict response to prostate directed therapy (PDT).

MATERIALS/METHODS

We performed a single institution retrospective review of men with low-volume mCSPC who underwent next-generation sequencing of their tumor. Patients were classified according to the presence of high-risk (HiRi) mutation including pathogenic mutations in either TP53, ATM, BRCA1/2, or Rb1. Our primary endpoint was to determine the effect of PDT on overall survival (OS) in patients with and without a HiRi mutation. Survival analysis was performed with the Kaplan-Meier method compared with log-rank test and multivariable cox regression. Interaction between HiRi mutation and PDT was evaluated.

RESULTS

A total of 101 patients with synchronous low-volume CSPC were included in our analysis with a median follow-up of 44 months. Approximately half of patients were found to have a HiRi pathogenic mutation (48.5%) with TP53 mutations accounting for 75.5% of HiRi mutations. On multivariable cox regression PDT was associated with improvement in OS (HR = 0.37, 95% CI 0.16-0.88; p = 0.03). When stratified by presence of HiRi mutation, PDT was not associated with any clinical outcome. Patients with HiRi mutations demonstrated a median OS of 73 vs 66.8 months (p = 0.28) for no PDT and PDT, respectively. Conversely, patients without a HiRi mutation demonstrated a significant improvement in median OS of 60 vs 105.3 months (p<0.01) for no PDT and PDT, respectively. The p-value for interaction for OS between PDT and HiRi mutation was statistically significant (p<0.01).

CONCLUSION

Here we have identified a high-risk genomic biomarker that appears predictive for response to PDT in men with synchronous low-volume mCSPC. Further work validating these results with prospective randomized data is warranted.

A143 PEDIATRIC EOSINOPHILIC ESOPHAGITIS IN CANADA: A MULTI-CENTER COHORT WITH FOCUS ON THE STRICTURING PHENOTYPE

Background

Eosinophilic esophagitis (EoE) is a chronic eosinophil-predominant esophageal inflammatory condition, and is now recognized as one of the most common organic causes of dysphagia in pediatrics. While fibrostenotic esophageal strictures are a common complication of adult EoE, characterization of the stricturing phenotype in pediatric EoE remains at an early stage.

Purpose

Describe the Canadian pediatric EoE experience, with focus on the stricturing phenotype.

Method

New pediatric EoE diagnoses from 2015-2018 were retrospectively identified in Vancouver (BC), Northern Alberta (AB), Hamilton (ON) and Nova Scotia (NS). Incidence rates were calculated using 2016 Federal census data. Clinical, endoscopic and histologic data were gathered for each patient’s initial clinical encounter and for any esophagogastroduodenoscopies (EGD) until the end of the follow-up period (fall 2019).

Result(s)

332 new EoE cases were identified during the study period across all 4 sites. The incidence of EoE in patients less than 15 years old was 9.1 (AB), 6.5 (NS), 3.1 (BC) and 5.4 (combined) per 100,000 person-years. Incidence was not calculated for Hamilton due to risk of ascertainment bias given their catchment area overlaps with multiple other centers. Of identified cases, 40 (12.0%) had endoscopically-identified esophageal strictures at diagnosis or during the follow-up period, with a subset of 11 (3.3%) of these patients undergoing mechanical esophageal dilation. Another 11 (3.3%) patients had more subtle signs of esophageal narrowing (ex. mucosal rents), while the majority had no evidence of esophageal narrowing (281, 84.6%). The median age at diagnosis was higher in the cohort with strictures (12.4 years, IQR 8.9-14.1) than those without (10.3 years, IQR 6.1-13.6) but with wide IQR's. A similar trend was seen for the median duration of symptoms at diagnosis (1.5 years, IQR 0.5-3 versus 1.0 years, IQR 0.6-2.8). Patient reported food bolus impaction (OR 9.8, 95% CI 3.9-19.9) and dysphagia (OR 3.3, 95% CI 1.3-7.8) were associated with stricturing disease, with other symptoms less clearly linked. Trachealization was the endoscopic finding most closely associated with esophageal strictures (OR 5.7, 95% CI 2.8-11.5). Esophageal stricture(s) were noted on 72 EGDs, including 27 endoscopic esophageal dilations, but excluding 10 esophageal dilations by interventional radiology. Of the 65 EGDs done in follow-up of a known esophageal stricture (see Table), 4 of 31 had resolution of this finding post mechanical dilation, and 19 of 39 had resolution of the stricture after initiation of new medical or dietary treatments (without dilation).

Conclusion(s)

EoE is common in Canadian children, with esophageal strictures within a few years of diagnosis in 12% of cases. Interestingly, a large portion of strictures resolved without mechanical dilation, which seems to point away from fibrosis as the primary driver of esophageal strictures in this patient population.

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CAG, Other

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Women and Children's Health Research Institute

Disclosure of Interest

None Declared

A175 REAL-WORLD EXPERIENCE ON SWITCHING FROM ADALIMUMAB TO BIOSIMILARS IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE – AN OBSERVATIONAL STUDY FROM THREE TERTIARY CARE CENTRES

Background

Inflammatory Bowel Disease (IBD) is a chronic inflammatory condition of the bowel which includes ulcerative colitis (UC), Crohn’s disease (CD) or unspecific IBD (IBDu). Adalimumab (ADA), a humanized monoclonal IgG antibody against tumour necrosis factor-alpha (TNFa), is an effective treatment for IBD. Humira^TM is an anti-TNFa agent that was approved by Health Canada for the treatment of IBD. In May of 2019, the British Columbia government pharmaceutical benefit plan implemented a biosimilar initiative in May 2019, mandating a non-medical switch from Humira^TM to one of the biosimilar drugs.

Purpose

We aimed to evaluate the real-world experience on the comparative safety and effectiveness of adalimumab biosimilar therapy after a mandatory, non-medical switch.

Method

We performed a retrospective chart review of all patients with IBD who either remained on Humira^TM or were switched to an adalimumab biosimilar agent, Idacio, at three tertiary care centres. Patients’ demographic data, disease status including CRP and fecal calprotectin before and after switch, and hospital visits or admission after switch were collected. Statistical analysis was performed using ANOVA and t-test.

Result(s)

Of the 191 patients included in the study, 145 patients underwent the provincial mandated switch from Humira^TM to a biosimilar agent, Idacio® , whereas 46 patients remained on Humira^TM. The median age at IBD diagnosis was 27 years (range 3-76 years), and at biosimilar switch was 43.5 years (15-78 years). Median disease duration prior to biosimilar switch was 13.5 years (range 0-69 years). 55.1% of patients were male, and 12.9% of patients were active smokers. CD was found in 78.9% of patients, and 19.9% of patients had UC. After biosimilar switch, adverse events, such as rash, nausea, or vomiting, were noted in 10 patients in the biosimilar group, and 7 patients required switch back to Humira^TM. All patients in the Humira^TM group stayed on that therapy. One patient stopped the biosimilar agent due to development of a new cancer requiring chemotherapy. None of the patients required IBD-related emergency department visit or hospital admission. Additionally, there was no difference in CRP or fecal calprotectin values measured before and after the biosimilar switch, and when compared to the patients who stayed on Humira^TM (p=0.48, and p=0.142, respectively).

Conclusion(s)

We conclude that the clinical benefit of Humira^TM was sustained after a non-medical switch to an adalimumab biosimilar. There was no risk of relapse, emergency visit, or hospital admission seen in this study. This is the first Canadian study to establish the safety and efficacy of switch to non-medical switch to an adalimumab biosimilar agent.

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None

Disclosure of Interest

None Declared

CS014 is a novel HDAC inhibitor regulating the platelet activity, fibrinolysis and clot stability for prevention of thrombosis without increased risk of bleeding

Background

Cardiovascular disease is the leading cause of morbidity and mortality. A major challenge with current antithrombotic treatments is the increased risk of bleeding associated with effective inhibition of clot formation. We have developed a novel histone deacetylase inhibitor (HDACi) that effectively prevents occlusive thrombosis following vascular injury without increasing bleeding diathesis commonly associated with antithrombotic drugs.

Purpose

Develop an HDACi and antiplatelet drug, CS014, with an improved efficacy/safety profile and reduced bleeding risk compared with current anticoagulant and antiplatelet therapeutic approaches used to prevent thrombosis.

Methods

We assessed thrombosis and bleeding in mouse models by labelling platelets and fibrin and measuring accumulation at the site of injury using intravital microscopy. Drug was administered IP for 5 days prior to the experiments. Degree of clot formation in the vessel was assessed in the 1) laser-induced cremaster thrombosis assay, 2) carotid artery FeCl3 thrombosis assay, and 3) saphenous vein rebleeding laser-induced puncture wound assay. Bleeding was assessed in the tail vein bleeding assay. Potential off-target effects were studied using thromboelastography (TEG).

Results

CS014 treatment significantly reduced clot formation and fibrin formation at the site of injury in the laser-induced cremaster arteriole thrombosis assay (Fig. 1). FeCl3-induced injury of the carotid artery resulted in full occlusion of the carotid artery within 12–15 minutes. Treatment with CS014 was able to prevent full occlusion of the carotid artery, supporting its benefit in arterial injury conditions. In the saphenous vein rebleeding assay, fibrin and platelet accumulation at the site of injury wound was significantly inhibited, suggesting that CS014 functions in both arterial and venous systems to attenuate clot and thrombosis. The tail vein bleeding assay confirmed that while the thrombus formation and stability was decreased based on the cremaster and carotid artery assays, no significant change was observed in bleeding time under these conditions. Finally, TEG experiments in mouse blood treated with or without CS014 demonstrated no delay or decrease in clot strength confirming the prevention of a bleeding diathesis observed in the tail vein bleeding assay experiments.

Conclusions

We have shown for the first time that the HDACi CS014 results in inhibition of mouse thrombosis and decreased time to clot resolution without an increased risk of bleeding. This discovery represents a new class of inhibitors for prevention of platelet activation and thrombosis with the potential to protect from myocardial infarction and stroke while increasing fibrinolytic ability in the blood to limit the risk of thromboembolism on the venous side, with no signs of increased bleeding risk.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Cereno Scientific

Enrichment in procoagulant microparticles in calcified human aortic valve – role in valvular endothelium alterations and enhanced thrombogenicity

Background

Aortic stenosis (AS) is characterized by endothelial dysfunction (ED), inflammatory cell infiltration, myofibroblastic and osteoblastic differentiation. Subclinical leaflet thrombosis was recently linked to higher rates of stroke and transient ischemic attack after transcatheter aortic valve implantation (TAVI). Procoagulant microparticles (MPs) are associated with ED, inflammation and clot formation. There is limited evidence regarding intra-valvular MPs content and their potential biological effects. This question is particularly relevant in TAVI in which the residing native valve could constitute a source of thrombotic activity enhancing leaflet thrombosis and valve dysfunction.

Purpose

Therefore, we hypothesized that MPs trapped within the native aortic valve contribute to valvular dysfunction including enhanced thrombogenicity.

Methods

Human valves were collected from patients undergoing surgical valve replacement for AS or aortic insufficiency (AI). Pro-thrombotic, pro-inflammatory, and ED markers were identified in the calcified vs non-calcified part of the valves by Western-blot. Calcium content was measured through colorimetric method. MPs were extracted from human pathological valves, and quantified through their prothrombinase activity. Primary cultures of porcine valvular endothelial cells (VEC) were treated with the MPs (10 nmol/L) or thrombin (1U/ml) for 24hrs. Phenotypic change was appreciated through gene expression pattern assessed by RT-qPCR. IL-8 secretion was measured by ELISA.

Results

The phenotype of the AS valve was characterized through increased expression of thrombogenic (tissue factor, thrombomodulin, PAI-1), adhesive (VCAM-1, ICAM-1) and inflammatory (COX-1, COX-2) molecules in the calcified part of the valve. Moreover, MPs content was increased in the calcified vs non-calcified part of the valve or AI valves. MPs levels was correlated with valvular calcium content (R=0.3862: p&lt;0.001). Tissue factor was increased in MPs extracted from AS vs AI. The biological effect of MPs was tested on VEC in-vitro. Results showed dramatic increase in expression of inflammatory cytokines (CXCL10, CCL11, CXCL8, MCP1) adhesion molecules (VCAM-1, ICAM-1, SELP, SELE) and proangiogenic factors (VEGFR2, ANGPTL4) in VEC exposed to MPs (24h) from AS vs AI. Enhanced secretory phenotype was evidenced through IL-8 determination in the supernatant of VEC stimulated with MPs from AS valve.

Conclusion

Calcified aortic valve is a potent reservoir of MPs, acting as a pro-thrombogenic source per se and promoting a switch of VEC phenotype toward prothrombotic, proinflammatory and proangiogenic pattern. These data suggest that MPs released from the native valve constitute an important source of mediators involved in enhanced thrombogenicity and valvular remodeling.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): GERCA-Groupe Etudes Reali Commercia Avignon

P12.09.B Extracellular vesicle derived-miR-146a increases melanoma brain metastasis progression via Notch signalling pathway dysregulation

Background

Melanoma has the highest tropism of any cancer to metastasize to the brain, and 40% of late-stage patients develop brain metastasis. Invasion, survival, and progression of tumors is dependent on the support of the surrounding microenvironment; therefore, modulation of neighboring cells is a key factor in metastasis. Extracellular vesicles (EVs) are important in cell-to-cell signalling, shuttling proteins, RNA and DNA to alter the surroundings into a favorable tumor microenvironment. Our aims were to investigate the role of melanoma brain metastasis (MBM) derived EVs in MBM development to find possible contributing mechanisms to cancer progression for eventual therapeutic targeting.

Material and Methods

MBM-EVs isolated via sequential ultracentrifugation were injected into mice as a pre-treatment prior to intracardial injection of MBM cells. EVs were co-cultured with normal human astrocytes (NHA) to investigate phenotypic changes. MiRNA sequencing was performed on EVs collected from MBM cells and compared to NHA and melanocytes to determine a candidate miRNA for targeting. In situ hybridization was utilized to evaluate the level of miRNA in clinical patient MBM samples. Functional in vivo validation was performed by injecting miRNA knockout MBM cells into mice. Sequencing of NHA in the presence or absence of target miRNA mimic was used to determine downstream targets.

Results

Mice primed with EVs had a significant increase in MBM tumor burden, compared to non-primed mice. Co-culture with MBM-EVs resulted in NHA activation in vitro, with increased proliferation, invasion, cytokine production, and upregulation of GFAP. MiR-146a was highly upregulated in MBM EVs, and miR-146a mimics activated NHA. Patient samples had a significant increase in miR-146a expression, compared to healthy brain controls. MiR-146a knockdown in MBM mice models reduced MBM burden and prolonged animal survival. Sequencing of NHA determined NUMB, an inhibitor of the Notch signalling pathway, as a target of miR-146a. Numb and other downstream Notch proteins expression was significantly altered in NHA in the presence of both MBM-EVs and miR-146a.

Conclusion

In conclusion, EVs are important regulators of MBM and establish tumor-supporting reactive astrocytes by delivery of miR-146a. MiR-146a alters Notch signalling in astrocytes via inhibition of the tumor suppressor gene NUMB. Elevated miR-146a levels in patients suggests a potential clinical intervention is possible via miR-146a targeting.

Soft wetting with (a)symmetric Shuttleworth effect

The wetting of soft polymer substrates brings in multiple complexities when compared with the wetting on rigid substrates. The contact angle of the liquid is no longer governed by Young’s Law, but is affected by the substrate’s bulk and surface deformations. On top of that, elastic interfaces exhibit a surface energy that depends on how much they are stretched—a feature known as the Shuttleworth effect (or as surface-elasticity). Here, we present two models through which we explore the wetting of drops in the presence of a strong Shuttleworth effect. The first model is macroscopic in character and consistently accounts for large deformations via a neo-Hookean elasticity. The second model is based on a mesoscopic description of wetting, using a reduced description of the substrate’s elasticity. While the second model is more empirical in terms of the elasticity, it enables a gradient dynamics formulation for soft wetting dynamics. We provide a detailed comparison between the equilibrium states predicted by the two models, from which we deduce robust features of soft wetting in the presence of a strong Shuttleworth effect. Specifically, we show that the (a)symmetry of the Shuttleworth effect between the ‘dry’ and ‘wet’ states governs horizontal deformations in the substrate. Our results are discussed in the light of recent experiments on the wettability of stretched substrates.

A Cough-based deep learning framework for detecting COVID-19

This paper presents a deep learning framework for detecting COVID-19 positive subjects from their cough sounds. In particular, the proposed approach comprises two main steps. In the first step, we generate a feature representing the cough sound by combining an embedding extracted from a pre-trained model and handcrafted features extracted from draw audio recording, referred to as the front-end feature extraction. Then, the combined features are fed into different back-end classification models for detecting COVID-19 positive subjects in the second step. Our experiments on the Track-2 dataset of the Second 2021 DiCOVA Challenge achieved the second top ranking with an AUC score of 81.21 and the top F1 score of 53.21 on a Blind Test set, improving the challenge baseline by 8.43% and 23.4% respectively and showing deployability, robustness and competitiveness with the state-of-the-art systems.

An Ensemble of Deep Learning Frameworks for Predicting Respiratory Anomalies

This paper evaluates a range of deep learning frameworks for detecting respiratory anomalies from input audio. Audio recordings of respiratory cycles collected from patients are transformed into time-frequency spectrograms to serve as front-end two-dimensional features. Cropped spectrogram segments are then used to train a range of back-end deep learning networks to classify respiratory cycles into predefined medically-relevant categories. A set of those trained high-performance deep learning frameworks are then fused to obtain the best score. Our experiments on the ICBHI benchmark dataset achieve the highest ICBHI score to date of 57.3%. This is derived from a late fusion of inception based and transfer learning based deep learning frameworks, easily outperforming other state-of-the-art systems. Clinical relevance--- Respiratory disease, wheeze, crackle, inception, convolutional neural network, transfer learning.

POS0746 MEASUREMENT OF ANTI-SUPRABASIN ANTIBODIES, MULTIPLE CYTOKINES AND CHEMOKINES AS POTENTIAL PREDICTIVE BIOMARKERS FOR NEUROPSYCHIATRIC SYSTEMIC LUPUS ERYTHEMATOSUS

Background

The pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) is multifactorial and involves diverse cytokines, autoantibodies and immune complexes inducing blood-brain barrier (BBB) dysfunction, neuroendocrine-immune imbalance, vascular occlusion, tissue, and neuronal damage. Several pro-inflammatory cytokines have been implicated in the pathogenesis of NPSLE [1]. Previously we have shown that the titer of anti-suprabasin (SBSN) antibodies in cerebrospinal fluid (CSF) of NPSLE patients was significantly higher than in SLE, MS and NPH groups [2]. However, distinguishing NPSLE from other neuropsychiatric conditions with different etiologies is challenging.

Objectives

This study determined the most critical serum biomarkers for the development of NPSLE as they may have clinical utility prior to the onset of neuropsychiatric symptoms.

Methods

We retrospectively analyzed 35 NPSLE patients, 34 SLE patients, 20 viral meningitis (VM) patients, and 16 relapsing-remitting multiple sclerosis (MS) patients. We measured anti-SBSN antibodies concentrations in serum by using Luciferase immunoprecipitation system (LIPS) assay. The serum concentrations of cytokines/chemokines were measured by using multiplex bead-based assay. All the clinical information and laboratory tests were collected at the time of admission.

Results

The Bayesian posterior mean and 95% HPDI of the cut-off of AI and its PPV and 1-NPV values were 5.26 (3.68;7.17), 0.87, (0.72; 1.0) and 0.44, (0.36; 0.5), respectively (Figure 1).

Figure 1.

Summary of the posterior distribution of the cutoff of AI and its predictive value (1-NPV and PPV). The 95% HPDI is shown as the thick black horizontal line with the boundaries written above the line

Among analyzed biomarkers, VEGF had the highest sparsity-oriented important learning (SOIL) importance, followed by AI, sCD40L, IL-10, GRO, MDC, IL-8, IL-9, TNFα, MIP-1α (Figure 2).

Figure 2.

Top 10 biomarkers having highest SOIL importance in prediction of NPSLE.

Abbreviations

• AI: anti-SBSN antibody index

• PPV: positive predictive

• NPV: negative predictive value

• SOIL: sparsity-oriented important learning

• IL: interleukin

•MIP: macrophage inflammatory protein

• sCD40L: soluble CD40 ligand

• MDC: macrophage-derived chemokine

• VEGF: vascular endothelial growth factor

• MDC: macrophage-derived chemokine

• TNF: Tumor necrosis factor

Conclusion

Our data demonstrated the ranking of serum biomarkers for the prediction of NPSLE. The most essential biomarkers are VEGF, anti-SBSN antibodies, sCD40L, IL-10, GRO, MDC, IL-8, IL-9, TNFα, MIP-1α.

References

[1]Govoni M, Hanly JG: Rheumatology (Oxford), 2020: 59(Suppl5):v52-v62.

[2]Ichinose K, et al: Clinical immunology, 2018; 193:123-130.

Disclosure of Interests

None declared

P16.08 Inhibition of melanoma brain metastasis by targeting miR-146a

BACKGROUND

Melanoma has the highest propensity of any cancer to metastasize to the brain, with late-stage patients developing brain metastasis (MBM) in 40% of cases. Survival of patients with MBM is around 8 months with current therapies, illustrating the need for new treatments. MBM development is likely caused by molecular interactions between tumor cells and the brain, constituting the brain metastatic niche. miRNAs delivered by exosomes released from the primary tumor cells may play a role in niche establishment, yet the mechanisms are poorly understood. Here, the aim was to identify miRNAs released by exosomes from melanomas, which may be important in niche establishment and MBM progression.

MATERIAL AND METHODS

miRNAs in exosomes collected from human astrocytes, melanocytes, and MBM cell lines were profiled to determine differential expression. Functional in vitro validation was performed by cell growth and migration assays, cytokine arrays, qPCR and Western blots. Functional in vivo studies were performed after miR knockdown in MBM cell lines. An in silico docking study was performed to determine drugs that potentially inhibit transcription of miR-146a to impede MBM development.

RESULTS

miR-146a was the most upregulated miRNA in exosomes from MBM cells and was highly expressed in human and animal MBM samples. miR-146a mimics activated human astrocytes, shown by increased proliferation and migration, elevated expression of GFAP in vitro and in mouse brain tumor samples, and increased cytokine production. In animal studies, knockdown of miR-146 in MBM cells injected intracardially into mice reduced BM burden and increased animal survival. Based on the docking studies, deserpidine was found to be an effective inhibitor of MBM growth in vitro and in vivo.

CONCLUSION

miR-146a may play an important role in MBM development, and deserpidine is a promising candidate for clinical use.

Odderon Exchange from Elastic Scattering Differences between pp and pp[over ¯] Data at 1.96 TeV and from pp Forward Scattering Measurements

We describe an analysis comparing the pp[over ¯] elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96 TeV to that in pp collisions as measured by the TOTEM Collaboration at 2.76, 7, 8, and 13 TeV using a model-independent approach. The TOTEM cross sections, extrapolated to a center-of-mass energy of sqrt[s]=1.96  TeV, are compared with the D0 measurement in the region of the diffractive minimum and the second maximum of the pp cross section. The two data sets disagree at the 3.4σ level and thus provide evidence for the t-channel exchange of a colorless, C-odd gluonic compound, also known as the odderon. We combine these results with a TOTEM analysis of the same C-odd exchange based on the total cross section and the ratio of the real to imaginary parts of the forward elastic strong interaction scattering amplitude in pp scattering for which the significance is between 3.4σ and 4.6σ. The combined significance is larger than 5σ and is interpreted as the first observation of the exchange of a colorless, C-odd gluonic compound.

A241 A REVIEW OF 101 CHILDREN WITH GASTRO-JEJUNAL FEEDING TUBES INCLUDING THEIR COMPLICATIONS AT BC CHILDREN’S HOSPITAL

Background

The use of GastroJejunal Tubes (GJTs) is an increasingly common method for providing post-pyloric enteral nutrition in pediatric patients.

Aims

To describe the patients with GJT including the indication, comorbidities including by system, as well as tube related complications.

Methods

The charts of 101 patients who had a GJT over a one-year period (2019–20) were retrospectively reviewed including demographics, medical diagnoses, information about tube placement, maintenance, and complications including malposition, balloon failure, blockages, and leakages / breaks.

Results

The top indications for GJT are aspiration and GERD. 73.3% have &gt;3 system comorbidities (ie CNS, GI, Resp). Mean age of GJT placement was 43 months. 78% remain on a PPI and 24% are on a prokinetic. 24% continue to eat some amount orally. Over this one-year period, 92% continue with a GJT (mean duration 4 years, max 15), 4% have reverted back to a G-tube, 1% had a surgical J tube placed, and 3% died (not due to the GJT). Following initial placement, these 101 patients underwent 1194 GJT related procedures, (417 urgent changes, 777 routine changes) with 98.3% technical success. Patients needed an average of one urgent repair per year (3.2/1000 GJT days) and the majority of patients required &gt;1 emergency visit. Those with routine GJT changes seem to have fewer urgent repairs (Figure 1).

Conclusions

Children with GJT represent a growing complex patient population. GJT are being used for the longer term. Routine maintenance seems supported by our data although doesn’t prevent the need for urgent repairs or other complications. Frameworks and guidelines are needed for this essential technology to improve clinical care.

Funding Agencies

None

Measurement of the Effective Weak Mixing Angle in pp[over ¯]→Z/γ^{*}→ℓ^{+}ℓ^{-} Events

We present a measurement of the effective weak mixing angle parameter sin^{2}θ_{eff}^{ℓ} in pp[over ¯]→Z/γ^{*}→μ^{+}μ^{-} events at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider and corresponding to 8.6  fb^{-1} of integrated luminosity. The measured value of sin^{2}θ_{eff}^{ℓ}[μμ]=0.23016±0.00064 is further combined with the result from the D0 measurement in pp[over ¯]→Z/γ^{*}→e^{+}e^{-} events, resulting in sin^{2}θ_{eff}^{ℓ}[comb]=0.23095±0.00040. This combined result is the most precise measurement from a single experiment at a hadron collider and is the most precise determination using the coupling of the Z/γ^{*} to light quarks.

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is A_{FB}^{tt[over ¯]}=0.128±0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions.

VOC exposures in California early childhood education environments

Little information exists about exposures to volatile organic compounds (VOCs) in early childhood education (ECE) environments. We measured 38 VOCs in single-day air samples collected in 2010-2011 from 34 ECE facilities serving California children and evaluated potential health risks. We also examined unknown peaks in the GC/MS chromatographs for indoor samples and identified 119 of these compounds using mass spectral libraries. VOCs found in cleaning and personal care products had the highest indoor concentrations (d-limonene and decamethylcyclopentasiloxane [D5] medians: 33.1 and 51.4 μg/m³, respectively). If reflective of long-term averages, child exposures to benzene, chloroform, ethylbenzene, and naphthalene exceeded age-adjusted "safe harbor levels" based on California's Proposition 65 guidelines (10^-5 lifetime cancer risk) in 71%, 38%, 56%, and 97% of facilities, respectively. For VOCs without health benchmarks, we used information from toxicological databases and quantitative structure-activity relationship models to assess potential health concerns and identified 12 VOCs that warrant additional evaluation, including a number of terpenes and fragrance compounds. While VOC levels in ECE facilities resemble those in school and home environments, mitigation strategies are warranted to reduce exposures. More research is needed to identify sources and health risks of many VOCs and to support outreach to improve air quality in ECE facilities.

Formaldehyde and acetaldehyde exposure and risk characterization in California early childhood education environments

Little information is available about air quality in early childhood education (ECE) facilities. We collected single-day air samples in 2010-2011 from 40 ECE facilities serving children ≤6 years old in California and applied new methods to evaluate cancer risk in young children. Formaldehyde and acetaldehyde were detected in 100% of samples. The median (max) indoor formaldehyde and acetaldehyde levels (μg/m³ ) were 17.8 (48.8) and 7.5 (23.3), respectively, and were comparable to other California schools and homes. Formaldehyde and acetaldehyde concentrations were inversely associated with air exchange rates (Pearson r = -0.54 and -0.63, respectively; P < 0.001). The buildings and furnishings were generally >5 years old, suggesting other indoor sources. Formaldehyde levels exceeded California 8-h and chronic Reference Exposure Levels (both 9 μg/m³ ) for non-cancer effects in 87.5% of facilities. Acetaldehyde levels exceeded the U.S. EPA Reference Concentration in 30% of facilities. If reflective of long-term averages, estimated exposures would exceed age-adjusted 'safe harbor levels' based on California's Proposition 65 guidelines (10^-5 lifetime cancer risk). Additional research is needed to identify sources of formaldehyde and acetaldehyde and strategies to reduce indoor air levels. The impact of recent California and proposed U.S. EPA regulations to reduce formaldehyde levels in future construction should be assessed.

Evidence for a B_{s}^{0}π^{±} State

We report evidence for a narrow structure, X(5568), in the decay sequence X(5568)→B_{s}^{0}π^{±}, B_{s}^{0}→J/ψϕ, J/ψ→μ^{+}μ^{-}, ϕ→K^{+}K^{-}. This is evidence for the first instance of a hadronic state with valence quarks of four different flavors. The mass and natural width of this state are measured to be m=5567.8±2.9(stat)_{-1.9}^{+0.9}(syst)  MeV/c^{2} and Γ=21.9±6.4(stat)_{-2.5}^{+5.0}(syst)  MeV/c^{2}. If the decay is X(5568)→B_{s}^{*}π^{±}→B_{s}^{0}γπ^{±} with an unseen γ, m(X(5568)) will be shifted up by m(B_{s}^{*})-m(B_{s}^{0})∼49  MeV/c^{2}. This measurement is based on 10.4  fb^{-1} of pp[over ¯] collision data at sqrt[s]=1.96  TeV collected by the D0 experiment at the Fermilab Tevatron collider.

Evidence for Simultaneous Production of J/ψ and ϒ Mesons

We report evidence for the simultaneous production of J/ψ and ϒ mesons in 8.1  fb^{-1} of data collected at sqrt[s]=1.96  TeV by the D0 experiment at the Fermilab pp[over ¯] Tevatron Collider. Events with these characteristics are expected to be produced predominantly by gluon-gluon interactions. In this analysis, we extract the effective cross section characterizing the initial parton spatial distribution, σ_{eff}=2.2±0.7(stat)±0.9(syst)  mb.

SCL/TAL1 in Hematopoiesis and Cellular Reprogramming

SCL, a transcription factor of the basic helix-loop-helix family, is a master regulator of hematopoiesis. Scl specifies lateral plate mesoderm to a hematopoietic fate and establishes boundaries by inhibiting the cardiac lineage. A combinatorial interaction between Scl and Vegfa/Flk1 sets in motion the first wave of primitive hematopoiesis. Subsequently, definitive hematopoietic stem cells (HSCs) emerge from the embryo proper via an endothelial-to-hematopoietic transition controlled by Runx1, acting with Scl and Gata2. Past this stage, Scl in steady state HSCs is redundant with Lyl1, a highly homologous factor. However, Scl is haploinsufficient in stress response, when a rare subpopulation of HSCs with very long term repopulating capacity is called into action. SCL activates transcription by recruiting a core complex on DNA that necessarily includes E2A/HEB, GATA1-3, LIM-only proteins LMO1/2, LDB1, and an extended complex comprising ETO2, RUNX1, ERG, or FLI1. These interactions confer multifunctionality to a complex that can control cell proliferation in erythroid progenitors or commitment to terminal differentiation through variations in single component. Ectopic SCL and LMO1/2 expression in immature thymocytes activates of a stem cell gene network and reprogram cells with a finite lifespan into self-renewing preleukemic stem cells (pre-LSCs), an initiating event in T-cell acute lymphoblastic leukemias. Interestingly, fate conversion of fibroblasts to hematoendothelial cells requires not only Scl and Lmo2 but also Gata2, Runx1, and Erg, indicating a necessary collaboration between these transcription factors for hematopoietic reprogramming. Nonetheless, full reprogramming into self-renewing multipotent HSCs may require additional factors and most likely, a permissive microenvironment.

Inclusive Production of the X(4140) State in pp[over ¯] Collisions at D0

We present a study of the inclusive production of the X(4140) state with the decay to the J/ψϕ final state in hadronic collisions. Based on 10.4  fb^{-1} of pp[over ¯] collision data collected by the D0 experiment at the Fermilab Tevatron collider, we report the first evidence for the prompt production of an X(4140) state and find the fraction of X(4140) events originating from b hadrons to be f_{b}=0.39±0.07(stat)±0.10(syst). The ratio of the nonprompt X(4140) production rate to the B_{s}^{0} yield in the same channel is R=0.19±0.05(stat)±0.07(syst). The values of the mass M=4152.5±1.7(stat)_{-5.4}^{+6.2}(syst)  MeV and width Γ=16.3±5.6(stat)±11.4(syst)  MeV are consistent with previous measurements.

Search for Violation of CPT and Lorentz Invariance in Bs(0) Meson Oscillations

We present the first search for CPT-violating effects in the mixing of Bs(0) mesons using the full Run II data set with an integrated luminosity of 10.4  fb(-1) of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the CPT-violating asymmetry in the decay Bs(0)→μ(±)Ds(±) as a function of celestial direction and sidereal phase. We find no evidence for CPT-violating effects and place limits on the direction and magnitude of flavor-dependent CPT- and Lorentz-invariance violating coupling coefficients. We find 95% confidence intervals of Δa⊥<1.2×10(-12)  GeV and (-0.8<ΔaT-0.396ΔaZ<3.9)×10(-13)  GeV.

Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element V_{tb}

We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb^{-1} per experiment. The t-channel cross section is measured to be σ_{t}=2.25_{-0.31}^{+0.29} pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in σ_{s+t}=3.30_{-0.40}^{+0.52} pb, without assuming the standard model value for the ratio σ_{s}/σ_{t}. The resulting value of the magnitude of the top-to-bottom quark coupling is |V_{tb}|=1.02_{-0.05}^{+0.06}, corresponding to |V_{tb}|>0.92 at the 95% C.L.

Measurement of the Effective Weak Mixing Angle in pp[over ¯]→Z/γ^{*}→e^{+}e^{-} Events

We present a measurement of the fundamental parameter of the standard model, the weak mixing angle sin^{2}θ_{eff}^{ℓ} which determines the relative strength of weak and electromagnetic interactions, in pp[over ¯]→Z/γ^{*}→e^{+}e^{-} events at a center of mass energy of 1.96 TeV, using data corresponding to 9.7 fb^{-1} of integrated luminosity collected by the D0 detector at the Fermilab Tevatron. The effective weak mixing angle is extracted from the forward-backward charge asymmetry as a function of the invariant mass around the Z boson pole. The measured value of sin^{2}θ_{eff}^{ℓ}=0.23147±0.00047 is the most precise measurement from light quark interactions to date, with a precision close to the best LEP and SLD results.

Tevatron constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quark pairs

Combined constraints from the CDF and D0 Collaborations on models of the Higgs boson with exotic spin J and parity P are presented and compared with results obtained assuming the standard model value JP=0+. Both collaborations analyzed approximately 10  fb(-) of proton-antiproton collisions with a center-of-mass energy of 1.96 TeV collected at the Fermilab Tevatron. Two models predicting exotic Higgs bosons with JP=0- and JP=2+ are tested. The kinematic properties of exotic Higgs boson production in association with a vector boson differ from those predicted for the standard model Higgs boson. Upper limits at the 95% credibility level on the production rates of the exotic Higgs bosons, expressed as fractions of the standard model Higgs boson production rate, are set at 0.36 for both the JP=0- hypothesis and the JP=2+ hypothesis. If the production rate times the branching ratio to a bottom-antibottom pair is the same as that predicted for the standard model Higgs boson, then the exotic bosons are excluded with significances of 5.0 standard deviations and 4.9 standard deviations for the JP=0- and JP=2+ hypotheses, respectively.

Measurement of the B(s)(0) lifetime in the flavor-specific decay channel B(s)(0)→D(s)(-)μ(+)νX

We present an updated measurement of the B(s)(0) lifetime using the semileptonic decays B(s)(0)→D(s)(-)μ(+)νX, with D(s)(-)→ϕπ(-) and ϕ→K(+)K(-) (and the charge conjugate process). This measurement uses the full Tevatron Run II sample of proton-antiproton collisions at √[s]=1.96  TeV, comprising an integrated luminosity of 10.4  fb(-1). We find a flavor-specific lifetime τ(fs)(B(s)(0))=1.479±0.010(stat)±0.021(syst)  ps. This technique is also used to determine the B(0) lifetime using the analogous B(0)→D(-)μ(+)νX decay with D(-)→ϕπ(-) and ϕ→K(+)K(-), yielding τ(B(0))=1.534±0.019(stat)±0.021(syst)  ps. Both measurements are consistent with the current world averages, and the B(s)(0) lifetime measurement is one of the most precise to date. Taking advantage of the cancellation of systematic uncertainties, we determine the lifetime ratio τ(fs)(B(s)(0))/τ(B(0))=0.964±0.013(stat)±0.007(syst).