Gas6 Levels Research Articles

Expression levels of serum mir-145-5p and Gas6 in women with early-onset preeclampsia and their clinical significance.

Early preeclampsia is a pregnancy-specific clinical disease, its pathogenesis is not clear, and clinical treatment is limited. Therefore, it is particularly important to study the pathogenesis of early preeclampsia, so as to provide evidence for the diagnosis and effective treatment of early preeclampsia. This research was carried out to investigate the expression levels and clinical significance of mir-145-5p and stagflation specific gene 6 (Gas6) in serum of women with early preeclampsia. For this purpose, 142 patients with preeclampsia were divided into the early-onset group (n=78) and the late-onset group (n=64) according to the onset time. Meanwhile, 70 normal pregnant women were selected as the control group. The levels of serum Gas6, mir-145-5p and inflammatory factors were detected. Logistic regression analysis showed that the expression levels of serum gas-6 and serum mir-145-5p were valuable in the diagnosis of early preeclampsia. ROC curve was established to evaluate the diagnostic efficacy of serum Gas6 level in early-onset preeclampsia. Its sensitivity and specificity were 91.23% and 64.2%, respectively, and the cutting value was 255.71pg/mL. The serum Gas6 level was negatively correlated with systolic blood pressure (r=-0.349, P<0.05) and positively correlated with platelet count (r=0.391, P<0.05). Compared with the control group, serum levels of mir-145-5p and TNF-a in women with early-onset preeclampsia were negatively correlated (r=-0.460~0.622, P<0.05). Conclusion: the serum level of Gas6 was reduced in patients with early-onset preeclampsia, and TNF-a inhibited the invasion of SVneo cells by upregulating mir-145-5p.

Association between plasma growth arrest-specific protein 6 and carotid atherosclerosis in type 2 diabetes mellitus

Background and aimsGrowth arrest-specific 6 protein (Gas6) has been established to play important roles in various biological processes, but little is currently known on the role of Gas6 signaling in humans. This research explored the association between Gas6 expression and carotid atherosclerosis (AS) in type 2 diabetes mellitus (T2DM). Methods and resultsAs many as 126 T2DM patients were recruited in this study and classified into two groups based on their carotid intima-media thickness (CIMT). Meanwhile, 50 healthy individuals were recruited for the normal control group (NC). The subgroups were compared in terms of clinical data and Gas6 expression levels. Gas6 levels were decreased in T2DM patients with or without AS compared to NC subjects (9.64 ± 1.41 ng/ml, 11.38 ± 2.08 ng/ml, and 13.64 ± 2.61 ng/ml, respectively) (p < 0.001). The interaction between Gas6 and AS in T2DM was analyzed by logistic regression model and receiver operating characteristic (ROC) curve analysis. Decreased Gas6 expression was an independent risk factor relevant to AS in T2DM (p = 0.027). The area under the ROC curve to estimate the diagnostic value of low Gas6 expression for AS in T2DM was 0.750. The correlation between Gas6 and other parameters was evaluated by Pearson correlation analysis and linear regression model. Body mass index (BMI), hemoglobin A1c (HbA1c) and tumor necrosis factor-α(TNF-α) were independently correlated with Gas6. ConclusionLow Gas6 expression is an independent risk factor for AS in T2DM. Gas6 expression is affected by BMI, HbA1c and TNF-α levels.

A new approach for the pleiotropic effect of metformin use in type 2 diabetes mellitus

Abstract Objectives Metformin is the first choice for type 2 diabetes mellitus (T2DM) treatment in the guidelines and is used in combination with many drugs. Growth arrest-specific protein 6 (Gas6)/Axl signaling plays a role in many metabolic disorders. This study aims to investigate the effects of metformin and metformin-insulin combination used in patients with T2DM on Gas6, Axl, and soluble Axl (sAxl) levels. Methods A total of 71 patients diagnosed with T2DM and 21 healthy subjects were divided into 4 groups control, diet and exercises recommended (DER), metformin, and metformin + insulin. Diabetic patients were treated with metformin only or with a metformin-insulin combination and monitored for six months. Gas6, Axl, and sAxl levels of subjects’ sera obtained from their baseline and post-therapeutic sixth month blood samples were measured by ELISA methods. Results Compared to baseline, the sixth month Gas6 and Axl levels of metformin and metformin + insulin groups significantly decreased (p&lt;0.05). However, there was no statistically significant difference in sAxl values for these two groups of patients. Conclusions The use of metformin in diabetic patients may be beneficial for inhibiting the Gas6/Axl pathway. This study presents a new aspect of the pleiotropic effects of metformin. This study will be clinically useful for designing therapeutic approaches targeting Gas6/Axl.

Baseline Plasma Gas6 Protein Elevation Predicts Adverse Outcomes in Hospitalized COVID-19 Patients.

Reliable biomarkers allowing early patients' stratification for the risk of adverse outcomes in COVID-19 are lacking. Gas6, together with its tyrosine kinase receptors named TAM, is involved in the regulation of immune homeostasis, fibrosis, and thrombosis. Our aim was to evaluate whether Gas6, sAxl, and sMerTK could represent early predictors of disease evolution either towards a negative (death or need of ICU admission) or a positive (discharge and/or clinical resolution within the first 14 days of hospitalization) outcome. To this purpose, between January and May 2021 (corresponding to third pandemic wave in Italy), 139 consecutive SARS-CoV-2 positive patients were enrolled in a prospective observational study. Plasma levels of these molecules were measured by ELISA at the time of hospitalization and after 7 and 14 days. We observed that higher plasma Gas6 concentrations at hospital admission were associated with a worsening in clinical conditions while lower sMerTK concentrations at baseline and after 7 days of hospitalization were associated with a more favorable outcome. At multivariate analysis, after correction for demographic and COVID-19 severity variables (NEWS2 and PiO2/FiO2), only Gas6 measured at baseline predicted an adverse prognosis with an odds ratio of 1.03 (C.I. 1.01-10.5). At ROC curve analysis, baseline Gas6 levels higher than 58.0 ng/ml predicted a severe disease evolution with 53.3% sensitivity and 77.6% specificity (area under the curve 0.653, p = 0.01, likelihood ratio of 2.38, IQR: 1.46-3.87). Taken together, these results support the hypothesis that a dysregulation in the Gas6/TAM axis could play a relevant role in modulating the course of COVID-19 and suggest that plasma Gas6 may represent a promising prognostic laboratory parameter for this condition.

Inhibition of Gas6 promotes crystalline silica-induced inflammatory response of macrophages via blocking autophagy flux.

Inhalation of crystalline silica (CS) can cause silicosis, which is one of the most serious interstitial lung diseases worldwide. Autophagy dysfunction is an essential step in silicosis progression. In this study, we aim to identify the effect of growth arrest-specific protein 6 (Gas6) during autophagy induction and macrophage inflammatory response caused by CS. After RAW 264.7 macrophages exposed to CS, the levels of Gas6 and autophagy markers (p62, Beclin1, and LC3-II/LC3-I) were increased, accompanied with enhanced inflammatory cytokines secretion. Using autophagy activator (rapamycin) repressed, whereas autophagy inhibitor (3-methyladenine) promoted inflammatory cytokines release. Besides, inhibition of Gas6 aggravated CS-induced inflammatory response, and autophagy inhibition facilitated the promoted effect of Gas6 silencing, resulting in elevated expression of inflammatory cytokines. These findings reveal the protective effects of Gas6 and autophagy in macrophages in response to CS exposure, and highlight the autophagy regulated by Gas6 may be a potential prevention target for CS-induced lung inflammatory response.

Are Baseline Levels of Gas6 and Soluble Mer Predictors of Mortality and Organ Damage in Patients with Sepsis? The Need-Speed Trial Database.

Soluble tyrosine kinase receptor Mer (sMer) and its ligand Growth arrest-specific protein 6 (Gas6) are predictors of mortality in patients with sepsis. Our aim is to clarify whether their measurement at emergency department (ED) presentation is useful in risk stratification. We re-analyzed data from the Need-Speed trial, evaluating mortality and the presence of organ damage according to baseline levels of sMer and Gas6. 890 patients were eligible; no association with 7- and 30-day mortality was observed for both biomarkers (p > 0.05). sMer and Gas6 levels were significantly higher in acute kidney injury (AKI) patients compared to non-AKI ones (9.8 [4.1–17.8] vs. 7.9 [3.8–12.9] ng/mL and 34.8 [26.4–47.5] vs. 29.8 [22.1–41.6] ng/mL, respectively, for sMer and Gas6), and Gas6 also emerged as an independent AKI predictor (odds ratio (OR) 1.01 [1.00–1.02]). Both sMer and Gas6 independently predicted thrombocytopenia in sepsis patients not treated with anticoagulants (OR 1.01 [1.00–1.02] and 1.04 [1.02–1.06], respectively). Moreover, sMer was an independent predictor of both prothrombin time-international normalized ratio (PT-INR) > 1.4 (OR 1.03 [1.00–1.05]) and sepsis-induced coagulopathy (SIC) (OR 1.05 [1.02–1.07]). An early measurement of the sMer and Gas6 plasma concentration could not predict mortality. However, the biomarkers were associated with AKI, thrombocytopenia, PT-INR derangement and SIC, suggesting a role in predicting sepsis-related organ damage.

The First Evaluation of Serum Levels of MGP, Gas6 and EGFR after First Dose of Chemotherapy in Lung Cancer.

Simple SummarySerum levels of MGP, Gas6, vitamin K1, and EGFR were not significantly changed in response to the first cycle of chemotherapy. We found a strong correlation between MGP and VitK1 serum values, and a moderate negative correlation between VitK1 and EGFR in pre-treatment patients. The post-treatment value of EGFR is a strong independent factor that correlates positively with the Gas6 post-treatment values.Background: Vitamin K-dependent proteins (VKDPs) and the epidermal growth factor receptor (EGFR) are involved in lung cancer progression. Therefore, we aimed to study the serum concentration of Matrix Gla protein (MGP), Growth Arrest-specific 6 (Gas6), and EGFR before and after the first cycle of chemotherapy and to investigate how MGP, Gas6, and EGFR are modified after one cycle of chemotherapy. Methods: We performed an observational study on twenty patients diagnosed with lung cancer, by assessing the serum concentration of vitaminK1 (VitK1), MGP, Gas6, and EGFR using the ELISA technique before and after three weeks of the first cycle of chemotherapy. Patients were evaluated using RECIST 1.1 criteria. Results: Serum levels of MGP, Gas6, EGFR, and VK1 before and after treatment were not changed significantly. Regarding the pre-treatment correlation of the MGP values, we found a strong positive relationship between MGP and VK1 pre-treatment values (r = 0.821, 95%CI 0.523; 0.954, p < 0.001). Furthermore, there was a moderately negative correlation between VK1 and EGFR pre-treatment values, with the relationship between them being marginally significant (r = −0.430, 95%CI −0.772; 0.001, p = 0.058). Post-treatment, we found a strong positive relationship between MGP and VK1 post-treatment values (r = 0.758, 95%CI 0.436; 0.900, p < 0.001). We also found a moderate positive relationship between Gas6 and EGFR post-treatment values, but the correlation was only marginally significant (r = 0.442, p = 0.051).

Soluble AXL is a novel blood marker for early detection of pancreatic ductal adenocarcinoma and differential diagnosis from chronic pancreatitis.

SummaryBackgroundEarly diagnosis is crucial for patients with pancreatic ductal adenocarcinoma (PDAC). The AXL receptor tyrosine kinase is proteolytically processed releasing a soluble form (sAXL) into the blood stream. Here we explore the use of sAXL as a biomarker for PDAC.MethodsAXL was analysed by immunohistochemistry in human pancreatic tissue samples. RNA expression analysis was performed using TCGA/GTEx databases. The plasma concentrations of sAXL, its ligand GAS6, and CA19-9 were studied in two independent cohorts, the HMar cohort (n = 59) and the HClinic cohort (n = 142), including healthy controls, chronic pancreatitis (CP) or PDAC patients, and in a familial PDAC cohort (n = 68). AXL expression and sAXL release were studied in PDAC cell lines and murine models.FindingsAXL is increased in PDAC and precursor lesions as compared to CP or controls. sAXL determined in plasma from two independent cohorts was significantly increased in the PDAC group as compared to healthy controls or CP patients. Patients with high levels of AXL have a lower overall survival. ROC analysis of the plasma levels of sAXL, GAS6, or CA19-9 in our cohorts revealed that sAXL outperformed CA19-9 for discriminating between CP and PDAC. Using both sAXL and CA19-9 increased the diagnostic value. These results were validated in murine models, showing increased sAXL specifically in animals developing PDAC but not those with precursor lesions or acinar tumours.InterpretationsAXL appears as a biomarker for early detection of PDAC and PDAC–CP discrimination that could accelerate treatment and improve its dismal prognosis.FundingThis work was supported by grants PI20/00625 (PN), RTI2018-095672-B-I00 (AM and PGF), PI20/01696 (MG) and PI18/01034 (AC) from MICINN-FEDER and grant 2017/SGR/225 (PN) from Generalitat de Catalunya.

Outcomes Based on Plasma Biomarkers for the Phase 3 CELESTIAL Trial of Cabozantinib versus Placebo in Advanced Hepatocellular Carcinoma

Introduction: Cabozantinib, an inhibitor of MET, AXL, and VEGF receptors, significantly improved overall survival (OS) and progression-free survival (PFS) versus placebo in patients with previously treated advanced hepatocellular carcinoma (HCC). In this exploratory analysis, outcomes were evaluated according to plasma biomarker levels. Methods: Baseline plasma levels were evaluated for MET, AXL, VEGFR2, HGF, GAS6, VEGF-A, PlGF, IL-8, EPO, ANG2, IGF-1, VEGF-C, and c-KIT for 674/707 randomized patients; and Week 4 levels were evaluated for MET, AXL, VEGFR2, HGF, GAS6, VEGF-A, PlGF, IL-8, and EPO for 614 patients. OS and PFS were analyzed by baseline levels as dichotomized or continuous variables and by on-treatment changes at Week 4 as continuous variables; biomarkers were considered potentially prognostic if p < 0.05 and predictive if p < 0.05 for the interaction between treatment and the biomarker. Multivariable analyses adjusting for clinical covariates were also performed. Results: In the placebo group, high levels of MET, HGF, GAS6, IL-8, and ANG2 and low levels of IGF-1 were associated with shorter OS in univariate and multivariable analyses; these associations were also observed for MET, IL-8, and ANG2 in the cabozantinib group. Hazard ratios for OS and PFS favored cabozantinib over the placebo at low and high baseline levels for all biomarkers. No baseline biomarkers were predictive of a treatment benefit. Cabozantinib promoted pharmacodynamic changes in several biomarkers, including increases in VEGF-A, PlGF, AXL, and GAS6 levels and decreases in VEGFR2 and HGF levels; these changes were not associated with OS or PFS. Conclusion: Cabozantinib improved OS and PFS versus placebo at high and low baseline concentrations for all biomarkers analyzed. Low baseline levels of MET, HGF, GAS6, IL-8, and ANG2 and high levels of IGF-1 were identified as potential favorable prognostic biomarkers for survival in previously treated advanced HCC. Although cabozantinib promoted pharmacodynamic changes in several biomarkers, these changes were not associated with survival.

Growth arrest-specific 6 protein in HIV-infected patients: Determination of plasma level and different antiretroviral regimens.

Growth arrest-specific 6 (Gas6) protein is involved in cell proliferation, differentiation, adhesion, migration in response to inflammatory processes. Human immunodeficiency virus (HIV) infection induces a chronic inflammatory condition and combination of antiretroviral therapy improves immune function and decreases the inflammatory state. The aim of this study was to assess the implications of Gas6 in chronic inflammation status of HIV-infected patients undergoing different third regimens of antiretroviral therapy. The Gas6 may be a marker of chronic inflammation of HIV-infected patients. A total of 356 adult males, including 258 HIV-infected patients and 98 healthy controls, were recruited. The demographic and clinical characteristics of the patients were collected. Laboratory assessment included hemogram, CD4 count, plasma HIV RNA load (PVL), hepatitis B and C viruses, and serum biochemistry. Plasma Gas6 concentrations were determined. The values of Gas6 were lower in HIV patients compared to healthy subjects (14.3±6.4 vs 21.5±15.2, p=0.01). HIV patients that received antiviral regimen with abacavir had similar Gas6 level than those who received antiviral regimens with tenofovir (14.3±6.5 vs 13.8±5.9, p=0.99). HIV patients that received antiviral regimen with protease inhibitors (PIs) had lower Gas6 level (13.1±3.5 vs 14.2±6.6 vs 14.6±6.5, p=0.03) than those who received antiviral regimens with non-nucleoside reverse transcriptase inhibitors (nNRTIs) and integrase inhibitors (INSTIs), respectively. Decreased plasma Gas6 concentrations were observed in HIV patients. Gas6 levels are associated with different third regimen of highly active antiretroviral therapy. Gas6 may represent a unique marker for assessing the chronic inflammation state difference among cART regimens in HIV patients.

Gas6/Axl signaling pathway promotes proliferation, migration and invasion and inhibits apoptosis in A549 cells.

Several studies have demonstrated that growth arrest-specific protein 6 (Gas6) and Axl are highly expressed in various tumor tissues, such as renal cell and esophageal carcinoma. However, the effect of the Gas6/Axl signaling pathway on lung adenocarcinoma is still unclear. The aim of the present study was to investigate the effect of the Gas6/Axl signaling pathway on lung adenocarcinoma cells and its mechanism of action, which may provide a novel target for the clinical treatment of lung adenocarcinoma. Human lung adenocarcinoma tissues were used to examine the activation of the Gas6/Axl signaling pathway. In addition, the human lung adenocarcinoma cell line A549 was employed to study the effects of the Gas6/Axl signaling pathway on the proliferation, migration, invasion and apoptosis of lung adenocarcinoma cells. Recombinant human Gas6 protein and inhibitor TP-0903 were used to activate and inhibit the Gas6/Axl signaling pathway, respectively. The results revealed that Gas6 and Axl expression level was increased in human lung adenocarcinoma tissues compared with adjacent healthy tissues. After inhibition of the Gas6/Axl signaling pathway with TP-0903, p21, p53, caspase 3, caspase 8 and caspase 9 exhibited higher expression level in A549 cells. The opposite effect was observed when the Gas6/Axl signaling pathway was activated. In addition, the migratory and invasive ability of A549 cells was determined via wound-healing and Transwell invasion assays. The results indicated that the migratory and invasive ability of A549 cells was significantly increased when the Gas6/Axl signaling pathway was activated and inhibition of Gas6/Axl signaling pathway caused the opposite results. Activity of Gas6/Axl signaling pathway was shown to be positively associated with cell proliferation by Cell Counting Kit 8 and clone formation assays. In conclusion, the Gas6/Axl signaling pathway was revealed to promote the proliferation, migration and invasion and inhibit the apoptosis of lung adenocarcinoma cells, which serve important roles in the progression of lung adenocarcinoma.

Gas6 drives Zika virus-induced neurological complications in humans and congenital syndrome in immunocompetent mice

Zika virus (ZIKV) has the ability to cross placental and brain barriers, causing congenital malformations in neonates and neurological disorders in adults. However, the pathogenic mechanisms of ZIKV-induced neurological complications in adults and congenital malformations are still not fully understood. Gas6 is a soluble TAM receptor ligand able to promote flavivirus internalization and downregulation of immune responses. Here we demonstrate that there is a correlation between ZIKV neurological complications with higher Gas6 levels and the downregulation of genes associated with anti-viral response, as type I IFN due to Socs1 upregulation. Also, Gas6 gamma-carboxylation is essential for ZIKV invasion and replication in monocytes, the main source of this protein, which was inhibited by warfarin. Conversely, Gas6 facilitates ZIKV replication in adult immunocompetent mice and enabled susceptibility to transplacental infection. Our data indicate that ZIKV promotes the upregulation of its ligand Gas6, which contributes to viral infectivity and drives the development of severe adverse outcomes during ZIKV infection.

Evolution of NETosis markers and DAMPs have prognostic value in critically ill COVID-19 patients

Coronavirus disease 19 (COVID-19) presents with disease severities of varying degree. In its most severe form, infection may lead to respiratory failure and multi-organ dysfunction. Here we study the levels and evolution of the damage associated molecular patterns (DAMPS) cell free DNA (cfDNA), extracellular histone H3 (H3) and neutrophil elastase (NE), and the immune modulators GAS6 and AXL in relation to clinical parameters, ICU scoring systems and mortality in patients (n = 100) with severe COVID-19. cfDNA, H3, NE, GAS6 and AXL were increased in COVID-19 patients compared to controls. These measures associated with occurrence of clinical events and intensive care unit acquired weakness (ICUAW). cfDNA and GAS6 decreased in time in patients surviving to 30 days post ICU admission. A decrease of 27.2 ng/mL cfDNA during ICU stay associated with patient survival, whereas levels of GAS6 decreasing more than 4.0 ng/mL associated with survival. The presence of H3 in plasma was a common feature of COVID-19 patients, detected in 38% of the patients at ICU admission. NETosis markers cfDNA, H3 and NE correlated well with parameters of tissue damage and neutrophil counts. Furthermore, cfDNA correlated with lowest p/f ratio and a lowering in cfDNA was observed in patients with ventilator-free days.

An epigenetic switch regulates the ontogeny of AXL-positive/EGFR-TKi-resistant cells by modulating miR-335 expression.

Despite current advancements in research and therapeutics, lung cancer remains the leading cause of cancer-related mortality worldwide. This is mainly due to the resistance that patients develop against chemotherapeutic agents over the course of treatment. In the context of non-small cell lung cancers (NSCLC) harboring EGFR-oncogenic mutations, augmented levels of AXL and GAS6 have been found to drive resistance to EGFR tyrosine kinase inhibitors such as Erlotinib and Osimertinib in certain tumors with mesenchymal-like features. By studying the ontogeny of AXL-positive cells, we have identified a novel non-genetic mechanism of drug resistance based on cell-state transition. We demonstrate that AXL-positive cells are already present as a subpopulation of cancer cells in Erlotinib-naïve tumors and tumor-derived cell lines and that the expression of AXL is regulated through a stochastic mechanism centered on the epigenetic regulation of miR-335. The existence of a cell-intrinsic program through which AXL-positive/Erlotinib-resistant cells emerge infers the need of treating tumors harboring EGFR-oncogenic mutations upfront with combinatorial treatments targeting both AXL-negative and AXL-positive cancer cells.

Electrochemical immunosensing of Growth arrest‐specific 6 in human plasma and tumor cell secretomes

AbstractGrowth arrest‐specific 6 (GAS6) protein plays a key role in processes related to proliferation, inflammation, angiogenesis, and atherosclerotic plaque formation. In addition, it has been reported that plasma levels of GAS6 are related to cancer prognosis and other relevant pathologies, such as heart failure or sepsis. We report here the first electrochemical immunoplatform for the determination of GAS6, which has demonstrated to be competitive with other available methodologies in terms of cost, simplicity, and decentralized application. The developed immunoplatform involves a sandwich immunoassay using magnetic microparticles (MBs) and uses amperometric detection at disposable screen‐printed carbon electrodes (SPCEs). The MBs were modified with an antibody specific to GAS6 for its selective capture, which is further recognized by a biotinylated secondary antibody subsequently labeled with a streptavidin‐horseradish peroxidase (Strep‐HRP) conjugate. The electrochemical detection was carried out using the hydroquinone (HQ)/H2O2 system. The developed bioplatform exhibits a great selectivity and low limit of detection (27 pg/mL) that allowed the determination of the GAS6 circulating level in plasma samples from patients suffering heart failure (HF) and diagnosed with pancreatic ductal adenocarcinoma (PDAC), as well as the determination of the target protein in raw secretomes of human colorectal cancer cell lines.

Abstract 951: Evolution of antibody titers, growth factor levels and in vitro activity in the sera of patients enrolled in the EPICAL trial of afatinib combined with anti-EGF vaccination

Abstract Background: We have recently demonstrated that antibodies generated by vaccination (anti-EGFVacAbs) potentiate the effects of EGFR TKIs in epidermal growth factor receptor mutant (EGFR-mut) non-small cell lung cancer (NSCLC) cells growing in vitro and prevent the emergence of resistance to EGFRTKIs (1). Based on these preclinical results we have started the Epical Phase Ib clinical trial(NCT03623750), testing anti-EGF vaccination in combination with EGFR TKI in advanced EGFR-mut NSCLC patients. Methods: The EPICAL trial is a Multicenter, Open-Label, Exploratory Phase Ib Clinical Study in which 23 patients have been enrolled. Anti-EGF VacAbs is a vaccine for intramuscular administration that is designed to be used in conjunction with standard of care treatment which, in this study, is afatinib. Blood samples have been collected at baseline and every three months and sent to a central laboratory. The presence of EGFR mutations has been determined on purified DNA by 5′-nuclease real-time PCR (Taqman®) assay in presence of PNA. All the serum samples have been analyzed by ELISA to determine the levels of EGF, TGFα, HGF and GAS6, together with anti-EGF antibody titers. Sera of patients were added to EGFR-mutant cell lines growing in vitro and Western blot was used to analyze EGFR, AKT andERK activation. Results: Median EGF levels in the sera of enrolled patients was 179.5 pg/mL at baseline and no anti-EGFantibodies were detected. Three months after first immunization, median serum EGF levels decreased to30.8 pg/mL (p=0.0008) while the anti-EGF vaccination titers increased to 1:6000 (p=0.0012). Anti-EGF titers remained high and EGF levels low in the patient's sera for the duration of the trial. Regarding serum TGFα and HGF levels baseline were 19.4 pg/mL and 861.2 pg/mL, respectively, and after three months dropped to 7.9 pg/mL (p=0.0037) and 341.3 pg/mL (p=0.0259). In EGFR-mutant cell lines in culture, the activation of the EGFR, AKT or ERK was abrogated by the sera of immunized patients. Conclusions: Anti-EGF vaccination induces high anti-EGF antibody titers and effectively reducing the levels of EGF and other growth factors in the blood of advanced NSCLC patients. 1J Thorac Oncol. 2018 Sep;13(9):1324-1337. Citation Format: Silvia Garcia-Roman, Jordi Codony, Miguel Angel Molina-Vila, Nuria Jordana-Ariza, Beatriz Garcia, Monica Garzon, Clara Mayo de las Casas, Maria Jose Catalan, Andres Aguilar, Santiago Viteri, Andres F. Cardona, Delvys Rodríguez, Manuel Cobo, Noemi Reguart, Erik d'Hondt, Rafael Rosell. Evolution of antibody titers, growth factor levels and in vitro activity in the sera of patients enrolled in the EPICAL trial of afatinib combined with anti-EGF vaccination [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 951.

Elevated Gas6 Plasma Level As a Predictor of Venous Thromboembolism Recurrence and Mortality in a Prospective Multicenter Cohort of Elderly Patients with Venous Thromboembolism

Introduction:Venous thromboembolism (VTE) represents a worldwide major health issue and is a leading cause of cardiovascular death. Its incidence rises with age and in the elderly population, VTE not only carries a higher mortality but also a higher rate of VTE recurrence and major bleeding than in younger patients. An elevated D-dimer level after cessation of anticoagulant treatment is associated with a high rate of VTE recurrence, and might indicate the need for prolonged anticoagulation in unclear situations. However, since D-dimer plasma levels decline under anticoagulation therapy, their use to guide the duration of anticoagulation requires that patients stop their antithrombotic medication before the D-dimer testing assessment, thereby risking VTE recurrence in the meantime. Growth arrest-specific gene 6 (Gas6) is a pro-hemostatic protein with multiple functions, including an effect on coagulation and platelet function, enhancing platelet aggregation and expression of tissue factor in endothelial cells as well as promoting the recruitment of platelets and leukocytes to the endothelial cell membrane. The goal of this study was the assessment of the predictive ability of Gas6 levels for recurrent venous VTE and mortality, as well as the comparison to D-Dimer levels.Methods:The study was conducted between September 2009 and December 2013 as part of the Swiss Cohort of Elderly Patients with VTE (SWITCO65+), a prospective multicenter cohort study to assess medical outcomes and quality of life in elderly patients with acute VTE from all five universities and four high-volume non-university hospitals in Switzerland. For the present study, the clinical outcomes were VTE recurrence and mortality, which were assessed over a 3 year period. Blood-samples for assessment of Gas6 levels and D-Dimer levels were drawn at diagnosis of the index VTE and at 12 month follow-up.Results:The study included 864 patients. During the 3-years follow-up period, 100(11.6%) patients developed recurrent VTE and 170 (19.7%) died. At the time of index VTE diagnosis, median Gas6 level was 129.3% (IQR 108.9,156.6) and was significantly lower (93%, IQR 77.1, 111.7) at 12-months follow-up. Median D-dimer was 2493 ng/mL (IQR 1572.5, 3819.3) at time of index VTE diagnosis and was 644.5 ng/mL (IQR 399.3, 1153.5) 12 months after the index VTE. Correlation between Gas6 and D-dimer was weak, both at time of the index VTE (Spearman correlation, rs = 0.06) and 12 months later (rs = 0.24). Based on the C-Statistics, Gas6 (95% confidence interval [CI], 0.56, 0.51-0.62, p=0.031) and D-dimer (95% CI, 0.56, 0.50-0.62, p=0.043) levels at the time of the index event were predictive of VTE recurrence up to 36 months. Gas6 (95%CI, 0.69, 0.65 - 0.73, p<0.001) but not D-dimer (95%CI, 0.56, 0.50 - 0.62, p=0.043) levels at the diagnosis of the index VTE were predictive of mortality up to 36 months (p<0.001). VTE recurrence up to 24 months was predicted by Gas6 (95%CI, 0.62, 0.54-0.71, p=0.003) and D-dimer (95%CI, 0.59, 0.51-0.67, p=0.036) levels at 12-month follow-up. However, mortality up to 24 months was predicted by D-dimer (95%CI, 0.71, 0.65-0.78, p<0.001) but not Gas6 (95%CI, 0.52, 0.44-0.61, p=0.566) levels at 12-month follow-up. Continuous Gas6 levels at diagnosis of the index event were associated with VTE recurrence up to 6 months (adjusted hazard ratio [HR] 5.04, 95% CI, 2.14-11.88, p<0.001) and death up to 36 months (adjusted HR 5.00, 95%CI, 3.16-7.92, p<0.001). Changes in Gas6 levels from time of the index VTE diagnosis to 12 months later were predictive of VTE recurrence up to 24 months (95%CI, 0.59, 0.51-0.67, p=0.036) but not overall mortality (95%CI, 0.52, 0.44-0.61, p=0.566).Conclusion:Gas6 levels measured at diagnosis of acute VTE were associated with higher risk of VTE recurrence and mortality in an elderly population. In addition, 12 month after the first VTE episode, only Gas6 levels were associated with higher risk of VTE-recurrence, whereas higher D-Dimer levels were associated with higher mortality. Our findings suggest that a clinical decision to avoid prolonged anticoagulation could be made based on Gas6 plasma level in the elderly. DisclosuresNo relevant conflicts of interest to declare.

The Orally Available Selective Axl Inhibitor BGB324 Induces Diversification of the Immune Repertoire and Specific Changes in Plasma Biomarker Profiles

Introduction: The RTK Axl represents a novel therapeutic target in AML promoting proliferation and therapy resistance. In addition, Axl suppresses immune responses by decreasing antigen presentation and inhibiting NK cells. BGB324 is a first-in-class, orally available, selective Axl kinase inhibitor which is being explored as a therapy for solid tumours and myeloid malignancies. Selective blockade of Axl by BGB324 in AML is currently being explored in the Phase 1/2 trial BGBC003 (NCT02488408). Until now, n=25 patients have been treated in a classical 3+3 dose escalation design and treatment was generally well-tolerated (n=22 with AML and n=3 with MDS). Steady-state levels of BGB324 were achieved between three and six days after initiation of treatment. One AML patient achieved a CRi of five months, a second achieved a PR and another achieved clearance of circulating blasts accompanied by peripheral blood count recovery > three months (ORR 10%). Four additional AML patients (25%) experienced disease stabilisation for more than four months. Two MDS patients experienced a PR.Here, we report the spectrum of plasma proteins modulated by BGB324 in patients with AML/MDS and their relationship to treatment outcome and compound exposure. Furthermore, we analysed the B- and T- cell repertoire in order to assess potential effects of BGB324 on the immune response in AML patients.Methods: We used the DiscoveryMap panel (Myriad RBM) to measure plasma protein biomarker levels in a selection of patients pre-dose and at C2D1 and performed a cross-comparison with samples from an ongoing NSCLC study with BGB324 (BGBC004, NCT02424617) to identify candidates specifically modulated in AML. The TCRß repertoire was quantified by Next Generation Sequencing of DNA isolated from peripheral blood MNCs using an Illumina MiSeq sequencer. TCRß gene containing the entire Vß, Dß and Jß segments were amplified with BIOMED2-TCRß-A and -B primer pools. The IGH repertoire was analysed using BIOMED2-FR1/-FR3 primer pools. Using genomic DNA as template, the amplicons were tagged with Illumina adapters and indices in two consecutive PCR reactions. Demultiplexing and FastQ formated data output was generated by the MiSeq reporter. Analysis of TCRß and IGH data was performed on a Microsoft Cloud using our in-house analysis pipeline Pippa, which relies on MiXCR analysis tools.Results: Treatment with BGB324 significantly modulated Gas6, soluble Axl (sAxl), Angpt2, CXCL1 (GROalpha), SCGB1A1 (uteroglobin, club cell 10kDa protein) and PLAU (uPAR) levels in patient plasma. Of these, Gas6 was modulated after treatment with BGB324 in AML but not in lung cancer patients while CXCL1 and SCGB1A1 were only influenced in lung cancer patients. sAxl levels correlated with BGB324 exposure indicating that the shed Axl receptor represents a novel biomarker of Axl kinase inhibition.Furthermore, we studied the effects of BGB324 on the T- and B- cell receptor repertoire in n=5 available matched PB samples. We could demonstrate diversification of the TCR repertoire in PB by higher abundance of small T-cell clones at C2D1 with BGB324 compared to pre-treatment levels in three out of five analysed patients.The analyses of the IGH repertoire in the PB indicates higher diversity at C2D1 in two out of five available patients.Thus, treatment with BGB324 can increase the diversity of the IGH and TCRb repertoire in the PB of AML patients.Conclusion: BGB324 is well tolerated in AML patients, exhibits anti-leukemic activity and induces exposure-related modulation of biomarker candidates. Furthermore, BGB324 can induce a diversification of the TCR repertoire in AML patients and might hold potential as an immune-activating drug. DisclosuresLoges:BerGenBio ASA: Research Funding. Ben-Batalla:BerGenBio ASA: Research Funding. Micklem:BerGenBio ASA: Employment, Equity Ownership, Patents & Royalties. Brown:BerGenBIo ASA: Employment. Lorens:BerGenBIo ASA: Employment, Equity Ownership, Patents & Royalties, Research Funding. Yule:BerGenBIo ASA: Employment. Fiedler:Amgen: Patents & Royalties; Amgen, ARIAD/Incyte: Membership on an entity's Board of Directors or advisory committees; Amgen, Pfizer: Research Funding; Amgen, Gilead, GSO, Teva, Jazz Pharmaceuticals: Other: Support for meeting attendance. Cortes:ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Sun Pharma: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; ImmunoGen: Consultancy, Research Funding; Teva: Research Funding.

Axl is related to inflammation in hemodialysis patients

BackgroundHemodialysis (HD) patients often develop chronic inflammation, which is associated with an increased risk of cardiovascular complications and mortality. Axl and its ligand, growth arrest 6 (Gas6), have been reported to play key roles in regulating the immune response. However, the function of Axl in HD patients has not been clarified. MethodsIn the present study, we enrolled 130 HD patients and 117 normal controls (NCs) and evaluated the levels of inflammatory markers, soluble Axl (sAxl), membrane Axl (mAxl), and Gas6 in all participants. The potential downstream cascades of Gas6-Axl signaling in HD patients were identified by quantitative real time polymerase chain reaction and western blotting. ResultsThe levels of inflammatory cytokines—tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ)—plasma sAxl, and Gas6, were significantly increased in HD patients compared to NCs. Additionally, sAxl was positively associated with the inflammatory factor, interleukin-6 (IL-6), in HD patients. Moreover, we found that mAxl in CD14+ mononuclear cells and CD19+ B cells was increased upon HD. Furthermore, we discovered that the metalloproteinase ADAM17, also called TACE, contributed to the cleavage of mAxl into sAxl, and not ADAM10, in the peripheral blood mononuclear cells (PBMCs) of HD patients. The upregulation of Gas6-mAxl signaling caused the activation of the STAT1-SOCS3 pathway in the PBMCs of HD patients. After two years follow-up, patients with lower sAxl levels had longer survival time than those with higher sAxl levels. ConclusionOur results suggest that Axl may play a significant role in systemic inflammation in HD patients.

Growth arrest-specific 6 as a predictor of gastroesophageal varices in patients with liver cirrhosis

Background and aim Early detection of patients with gastroesophageal varices at high risk of bleeding is crucial. Nevertheless, sparing endoscopy to low-risk patients would be of value. Therefore, noninvasive methods have been proposed. Our study aimed to verify whether plasma GAS6 concentrations are related to the presence and/or degree of esophageal varices in patients with LC. Patients and methods This cross-sectional study included 100 patients with LC who underwent upper gastrointestinal endoscopy. Results Mean level of GAS6 was 77.70±21.31 among enrolled patients. Patients with varices had significantly higher level of GAS6 in comparison with those without varices (82.93±18.12 vs. 45.57±4.18 ng/ml; P&lt;0.001). Level of serum GAS6 was also increased with advancement in the variceal grade. Conclusion Plasma level of GAS6 was higher among patients having varices in comparison with those without, and its level was increased with advancement in the grade of varices. GAS6 is reported to have a good predictive value for hepatic fibrosis in patients with chronic liver disease.