Secreted Embryonic Alkaline Phosphatase Research Articles

A synthetic notch (synNotch) system linking intratumoral immune-cancer cell communication to a synthetic blood biomarker assay.

Introduction: Cellular immunotherapy has greatly improved cancer treatment in recent years. For instance, chimeric antigen receptor (CAR) T cell therapy has been proven highly effective in treating hematological malignancies, and many CAR cell designs are being explored for solid tumors. However, many questions remain why responses differ across patients and some tumor types are resistant. Improved and relatively inexpensive ways to monitor these cells could provide some answers. Clinically, blood tests are regularly used to monitor these therapies, but blood signals often do not reflect the activity of immune cells within the tumor(s). Here, using the synthetic Notch (synNotch) receptor that tethers antigen binding to customized transgene expression, we linked intratumoral immune-cancer cell communication to a simple secreted reporter blood test. Specifically, we engineered immune cells with a CD19-targeted synNotch receptor and demonstrated that binding to CD19 on cancer cells in vivo resulted in the production of secreted embryonic alkaline phosphatase (SEAP) at levels that are readily detected in the blood. Methods and Results: Jurkat T cells were engineered via sequential lentiviral transduction of two components: an anti-CD19 synNotch receptor and a synNotch response element encoding SEAP. Co-culture of engineered cells with CD19+, but not CD19-, Nalm6 cells, resulted in significantly elevated SEAP in media. Nod-scid-gamma (NSG) mice were subcutaneously injected with either CD19+ or CD19- Nalm6 cells. Intratumoral injection of engineered T cells (1x107) resulted in significantly elevated blood SEAP activity in mice bearing CD19+ tumors (n = 7), but not CD19- tumors (n = 5). Discussion: Our synNotch reporter system allows for the monitoring of antigen-dependent intratumoral immune-cancer cell interactions through a simple and convenient blood test. Continued development of this system for different target antigens of interest should provide a broadly applicable platform for improved monitoring of many cell-based immunotherapies during their initial development and clinical translation, ultimately improving our understanding of design considerations and patient-specific responses.

Comparison of the Enzymatic and Cellular Profiles of Clinical JAK2 Inhibitors for the Treatment of Myelofibrosis

Introduction: Three Janus kinase 2 (JAK2) inhibitors (JAKinibs) have been approved by the FDA for the treatment of myelofibrosis (MF): ruxolitinib, fedratinib, and pacritinib; a fourth one, momelotinib, is currently under FDA review. In addition to JAK2, these drugs also inhibit other kinases with distinct profiles with potential implications in their observed pharmacology. Published data on kinase inhibitory profiles of the four JAKinibs are limited and were determined under differing assay conditions (Wernig G et al. Cancer Cell 2008; Pardanani A et al. Leukemia 2009; Quintás-Cardama A et al. Blood 2010; Singer J et al. J Exp Pharm 2016), which limits head-to-head comparisons and understanding of their JAK2 inhibition unrelated effects. Here, we present full kinome profiling data for these four JAKinibs. Additionally, we have compared their effects on signaling and proliferation in myeloid cells and other human cells. Methods and Results: Enzymatic assays performed in the presence of 1 mM ATP showed that ruxolitinib is the most potent JAK2 inhibitor (IC 50 4 nM) followed by fedratinib (14 nM), momelotinib (51 nM), and pacritinib (53 nM). Inhibition of other JAK family proteins such as JAK1 and TYK2 were also observed to varying degrees with each drug, and these enzymatic activities were consistent with inhibition of STAT signaling in response to different cytokines in secreted embryonic alkaline phosphatase (SEAP) cellular reporter assays (HEK-Blue Detection, InvivoGen, San Diego, CA). Full kinome analyses (372 activity assays of 356 unique wild-type protein kinases) were conducted (Reaction Biology, Malvern, PA) with determination of percentage inhibition at 100 nM of each drug with 10 μM ATP. Kinases exhibiting >50% inhibition with any of the drugs were then evaluated for dose-response to each drug with 100 μM ATP. The results shown in the Figure demonstrate that fedratinib, momelotinib, and pacritinib inhibited additional kinases outside of the JAK family with similar potency to JAK2 inhibition, whereas ruxolitinib was relatively selective for JAK2 inhibition. In contrast to published reports on the inhibitory activities of pacritinib and momelotinib against ALK2 ( ACVR1), the inhibition of ALK2 observed here was 5-10 times weaker than JAK2 inhibition. Furthermore, pacritinib and momelotinib were both weaker inhibitors of ALK2 activity when compared with their potency towards more than 30 other kinases screened. Fedratinib, pacritinib, and momelotinib, but not ruxolitinib, exhibited high inhibitory potencies against FLT3 and/or KIT kinases, both of which are critical for the self-renewal and differentiation of normal hematopoietic stem cells. In cellular assays monitoring JAK2 signaling (pSTAT5 level in SET2 cells), ruxolitinib was the most potent agent (IC 50 14 nM), followed by momelotinib (205 nM), pacritinib (429 nM), and fedratinib (672 nM). Similar trends were observed in other cellular assays assessing antiproliferative effects in JAK2-dependent myeloid cell lines. In cells not dependent on JAK pathway signaling for growth in culture, such as primary human fibroblasts and endothelial cells, ruxolitinib showed weak or no inhibition at 5 μM, while fedratinib, pacritinib and momelotinib showed anti-proliferative effects with low micromolar IC 50s. Similar trends were observed in human HEK293 and HepG2 cell lines, which are commonly used to assess drug effects on general cell health. We analyzed the effects of the JAKinibs on the differentiation of CD34 + hematopoietic stem and progenitor cells (HSPCs) derived from healthy donors at concentrations observed in the plasma of MF patients enrolled in clinical trials. Consistent with their activity on multiple kinases, including FLT3 and KIT, fedratinib and pacritinib elicited the most pronounced decrease in overall viability, affecting HSPCs and megakaryocytes. In contrast, ruxolitinib as a more selective JAK2 inhibitor, showed the least effect on the differentiation of normal CD34 + HSPCs. Conclusion: JAKinibs clinically evaluated for treatment of MF exhibit distinct kinase inhibition profiles and cellular activities. Amongst the agents tested in this study, ruxolitinib was the most potent and selective JAK2 inhibitor. At concentrations several fold above clinically relevant concentrations, ruxolitinib had no observable effects on the health of cells not reliant on JAK/STAT mediated signaling.

Preclinical Activity of Novel TGF Beta Receptor I Kinase Inhibitors IOA-359 and IOA-360 for Treatment of Anemia in MDS/AML

Background: Overactivation of the Transforming growth factor beta (TGF-β) superfamily has been associated with bone marrow failure in MDS. TGF-β binds to set of receptors that include the TGF-β receptor I kinase (also known as ALK5), that in turn phosphorylates and activates the downstream SMAD2/3 proteins. Activation of SMAD2/3 transcription factors has been shown to occur in MDS and is associated with anemia. Thus, we wanted to evaluate the preclinical efficacy of novel, clinic-ready, TGF-b receptor I kinase small molecule inhibitors IOA-359 and IOA-360 in MDS models. Results: Using the TREEspot™ SCAN Max Kinase Panel of 403 kinases, IOA-359 and IOA-360 were found to be highly selective for ALK5. Both, IOA-359 and IOA-360 have a blocking activity against ALK5 similar to clinical stage ALK5 inhibitors. To evaluate the efficacy of IOA-359 and IOA-360, we first used HEK 293- Blue-TGF-β cells that stably overexpresses a SMAD inducible secreted embryonic alkaline phosphatase (SEAP) reporter. Both IOA-359 and IOA-360 were able to significantly inhibit TGF-β driven reporter at nanomolar doses ( Fig1A). Next, we showed that both ALK5 inhibitors were able to block TGF-β-mediated SMAD2/3 downstream phosphorylation/activation in a dose dependent manner in MDS and leukemic cell lines. Functionally, the ALK5 inhibitors did not lead to any increase in viability or proliferation in leukemic cell lines. We next tested the efficacy of the novel ALK5 inhibitors in primary patient samples from MDS and AML (N=8). Treatment with both ALK5 inhibitors led to increase in erythroid colony formation in majority of MDS samples in clonogenic assays. Colonies were picked up and examined for erythroid and myeloid differentiation by FACS analysis. We observed that ALK5 inhibition led to increase in Glycophorin A and CD71 expression suggesting enhanced erythroid differentiation ( Fig1B). Myeloid differentiation effects were modest in comparison. Furthermore, in selected samples, addition of Luspatercept led to greater maturation of erythrocytes. Treatment of healthy CD34 + hematopoietic stem and progenitors did not lead to significant changes in differentiation. Lastly, to evaluate downstream effects of ALK5 inhibition, we performed RNAseq analysis in MDS cells. Inhibition with ALK5 inhibitors led to numerous changes in genes affecting cellular differentiation, validating functional changes observed by us. Conclusion: Our current results support the preclinical in vitro efficacy of ALK5 inhibitors IOA-359 and IOA-360 alone and in combination with Luspartercept, highlighting their potential for further development and clinical testing in MDS/AML.

Antioxidant and Anti-Inflammatory Activities of Phenolic Acid-Rich Extract from Hairy Roots of Dracocephalum moldavica.

This study evaluates the antioxidant properties and anti-inflammatory potential of polyphenolic acid-rich fractions of 80% methanolic extract from the hairy roots of Dracocephalum moldavica. The fractionation of the crude extract yielded the following: a diethyl ether fraction rich in caffeic acid (DM1) (25.85 mg/g DWE), an n-butyl fraction rich in rosmarinic acid (DM3) (43.94 mg/g DWE) and a water residue rich in salvianolic acid B (DM4) (51.46 mg/g DWE). The content of these compounds was determined using high-performance liquid chromatography (HPLC). Their antioxidant activity was evaluated based on DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt) and FRAP assays. The anti-inflammatory activity of the fractions was determined by their effect on nuclear factor kappa-B (NF-κB) activation and interleukin-1β (IL-1β) production in LPS E. coli stimulated monocytes. The level of pro-inflammatory IL-1β in cells was measured using ELISA. The activation of NF-κB in THP1-Blue™ cells, resulting in the secretion of SEAP (secreted embryonic alkaline phosphatase), was detected spectrophotometrically using Quanti-Blue reagent. Among the tested fractions, the diethyl ether fraction (DM1) showed the highest antioxidant potential, with an EC50 value of 15.41 µg/mL in the DPPH assay and 11.47 µg/mL in ABTS and a reduction potential of 10.9 mM Fe(II)/g DWE in FRAP. DM1 at a concentration of 10 mg/mL also efficiently reduced LPS-induced SEAP secretion (53% inhibition) and IL-1β production (47% inhibition) without affecting the normal growth of L929 fibroblast cells.

The combination of hexagonal microfluidic devices and cell-based reporter cells allows detection of cytokine-producing cells at the single-cell level

Cytokine production analysis at the single-cell level, such as detection of type I interferon (IFN-I), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) producing cells, is beneficial in clinical diagnostics and drug discovery. In this work, we developed a microfluidic device with hexagonal microchambers capable of generating single-cell/multicellular systems, oil-droplet compartmentalization, and performing functional assays based on green fluorescent protein (GFP) expression or secreted embryonic alkaline phosphatase (SEAP) secretion for cytokine secretion detection at single-cell level. Since the droplets are stationary, cell/cell-pairs are identified, and real-time monitoring and end-point analysis can be performed. At optimized conditions, up to 60% single-cell chamber occupancy can be achieved. Cytokines such as IFN-I, TNF-α, and IL-6 secreted by human immune cells (THP1 cells, plasmacytoid dendritic cells (pDCs), T-cells, B-cells, and monocytes) can be detected at the single-cell level upon pairing with GFP and SEAP expressing Human Embryonic Kidney (HEK)− 293 reporter cells. This proof-of-concept device has the potential to evaluate single-cell behaviors and could benefit the field of single-cell cytokine secretion monitoring.

Tocilizumab suppresses NF-kappa B activation via toll-like receptor 9 signaling by reducing cell-free DNA in rheumatoid arthritis.

Endogenous DNA is released into the bloodstream as cell-free DNA (cfDNA) following cell death and is associated with various pathological conditions. However, their association with therapeutic drugs against rheumatoid arthritis (RA) remains unknown. Therefore, we investigated the significance of cfDNA in RA treated with tocilizumab and tumour necrosis factor inhibitor (TNF-I). Biological DMARDs (bDMARDs), including tocilizumab and TNF-I, were administered to 77 and 59 RA patients, respectively. Plasma cfDNA levels were measured at weeks 0, 4, and 12 by quantitative polymerase chain reaction. Disease activity was evaluated at the same time point using DAS28ESR. cfDNA levels from RA synovial cells treated with tocilizumab or etanercept for 24 h were measured. Human toll-like receptor 9 (hTLR9)-expressing HEK293 cells, which release secreted embryonic alkaline phosphatase (SEAP) upon NF-κB activation, were stimulated by cfDNA from RA patients, and subsequently, SEAP levels were determined. NF-κB translocation was evaluated by immunofluorescence staining with or without tocilizumab. The DAS28ESR significantly improved in both bDMARD groups at week 12. However, plasma cfDNA levels significantly decreased in the tocilizumab group at week 12 compared to that in week 0. cfDNA levels correlated with DAS28ESR in biological treatment-naïve patients administered tocilizumab. cfDNA levels in synovial cells were significantly suppressed by tocilizumab treatment and unaltered with etanercept. HEK293 cells released SEAP upon cfDNA stimulation, and the observed NF-κB nuclear translocation was suppressed by tocilizumab. Tocilizumab suppressed inflammation via the TLR9 pathway by decreasing cfDNA levels. Regulation of cfDNA may be a therapeutic target for RA.

A Straightforward Method for the Development of Positively Charged Gold Nanoparticle-Based Vectors for Effective siRNA Delivery.

The therapeutic potential of short interfering RNA (siRNA) to treat many diseases that are incurable with traditional preparations is limited by the extensive metabolism of serum nucleases, low permeability through biological membrane barriers because of a negative charge, and endosomal trapping. Effective delivery vectors are required to overcome these challenges without causing unwanted side effects. Here, we present a relatively simple synthetic protocol to obtain positively charged gold nanoparticles (AuNPs) with narrow size distribution and the surface modified with Tat-related cell-penetrating peptide. The AuNPs were characterized using TEM and the localized surface plasmon resonance technique. The synthesized AuNPs showed low toxicity in experiments in vitro and were able to effectively form complexes with double-stranded siRNA. The obtained delivery vehicles were used for intracellular delivery of siRNA in an ARPE-19 cell line transfected with secreted embryonic alkaline phosphatase (SEAP). The delivered oligonucleotide remained intact and caused a significant knockdown effect on SEAP cell production. The developed material could be useful for delivery of negatively charged macromolecules, such as antisense oligonucleotides and various RNAs, particularly for retinal pigment epithelial cell drug delivery.

BacSp222 bacteriocin as a novel ligand for TLR2/TLR6 heterodimer

Objective and designBacSp222 bacteriocin is a bactericidal and proinflammatory peptide stimulating immune cells to produce selected cytokines and NO in NF-ĸB dependent manner. This study aims to identify the receptor which mediates this activity.MethodsWe applied fluorescently labeled BacSp222 and a confocal microscopy imaging to analyze the direct interaction of the bacteriocin with the cells. Reporter HEK-Blue cells overexpressing human toll-like receptors (TLR2, TLR4, TLR5 or TLR2/TLR1 and TLR2/TLR6 heterodimers) were stimulated with BacSp222, and then the activity of NF-ĸB-dependent secreted embryonic alkaline phosphatase (SEAP) was measured. In turn, formylated peptide receptor (FPR) or TLR2 antagonists were used to verify bacteriocin-stimulated TNF production by murine monocyte-macrophage cell lines.ResultsBacSp222 undergoes internalization into cells without disturbing the cell membrane. FPR antagonists do not affect TNF produced by BacSp222-stimulated murine macrophage-like cells. In contrast, BacSp222 stimulates NF-ĸB activation in HEK-Blue overexpressing TLR2 or TLR2/TLR6 heterodimer, but not TLR2/TLR1, TLR4 or TLR5 receptors. Moreover, TLR2-specific antagonists inhibit NF-ĸB signaling in BacSp222-stimulated HEK-Blue TLR2/TLR6 cells and reduce TNF release by BacSp222-treated RAW 264.7 and P388.D1.ConclusionsBacSp222 is a novel ligand for TLR2/TLR6 heterodimer. By binding TLR complex the bacteriocin undergoes internalization, inducing proinflammatory signaling that employs MyD88 and NF-ĸB pathways.

Measurement of Secreted Embryonic Alkaline Phosphatase.

Secreted reporters have been demonstrated to be simple and useful tools for analyzing transcriptional regulation in mammalian cells. The distinctive feature of these assays is the ability to detect reporter gene expression in the culture supernatant without affecting the cell physiology or leading to cell lysis, which allows repeated experimentation and sampling of the culture medium using the same cell cultures. Secreted embryonic alkaline phosphatase (SEAP) is one of the most widely used reporter, which can be easily detected using colorimetry following incubation with a substrate, such as p-nitrophenol phosphate. In this report, we present detailed procedures for detection and quantification of the SEAP reporter. We believe that this step-by-step protocol can be easily used by researchers to monitor and measure molecular genetic events in a variety of mammalian cells due to its simplicity and ease of handling. Graphical abstract Schematic overview of the workflow described in this protocol.

Immunomodulatory Effect of Human Lactoferrin on Toll-like Receptors 2 Expression as Therapeutic Approach for Keratoconus.

Keratoconus (KC) is a corneal disorder whose etiology shares a close relationship with Lactoferrin (LTF) dysregulation and Toll-like Receptors 2 (TLR2) overexpression. This study shows how these two important biomarkers are clinically and molecularly interrelated, increasing knowledge about KC pathophysiology, and opening the door to future therapies. In this prospective clinical study, serum and tear LTF concentrations were quantified in 90 KC patients and 60 controls. A correlation analysis with multiple blood and tear immunoinflammatory mediators, and KC-associated tomographic parameters, was performed. An in vitro study using HEK-BlueTMhTLR2 cell cultures was also conducted to determine the expression and functionality of TLR2 under the influence of LTF treatment. As a result, a LTF decreased was observed in KC patients compared to controls (p < 0.0001), evidencing the strong correlation with TLR2 overexpression at systemic and ocular surface level, with inflammatory mediator upregulation and with KC severity. In stimulated cell cultures, TLR2 expression was decreased using 2 mg/mL of LTF. The levels of secreted embryonic alkaline phosphatase (SEAP) and interleukin-8 (IL-8) were also reduced in supernatants after LTF treatment. As conclusions, the dysregulation of LTF and TLR2 in the ocular surface of KC patients contributes to KC severity by maintaining a detrimental chronic immune–inflammatory state. The immunomodulatory properties of LTF on TLR2 expression suggest its potential as a therapeutic approach for KC.

Influenza A virus NS1 protein represses antiviral immune response by hijacking NF-κB to mediate transcription of type III IFN.

BackgroundNon-structural protein 1 (NS1), one of the viral proteins of influenza A viruses (IAVs), plays a crucial role in evading host antiviral immune response. It is known that the IAV NS1 protein regulates the antiviral genes response mainly through several different molecular mechanisms in cytoplasm. Current evidence suggests that NS1 represses the transcription of IFNB1 gene by inhibiting the recruitment of Pol II to its exons and promoters in infected cells. However, IAV NS1 whether can utilize a common mechanism to antagonize antiviral response by interacting with cellular DNA and immune-related transcription factors in the nucleus, is not yet clear.MethodsChromatin immunoprecipitation and sequencing (ChIP-seq) was used to determine genome-wide transcriptional DNA-binding sites for NS1 and NF-κB in viral infection. Next, we used ChIP-reChIP, luciferase reporter assay and secreted embryonic alkaline phosphatase (SEAP) assay to provide information on the dynamic binding of NS1 and NF-κB to chromatin. RNA sequencing (RNA-seq) transcriptomic analyses were used to explore the critical role of NS1 and NF-κB in IAV infection as well as the detailed processes governing host antiviral response.ResultsHerein, NS1 was found to co-localize with NF-κB using ChIP-seq. ChIP-reChIP and luciferase reporter assay confirmed the co-localization of NS1 and NF-κB at type III IFN genes, such as IFNL1, IFNL2, and IFNL3. We discovered that NS1 disturbed binding manners of NF-κB to inhibit IFNL1 expression. NS1 hijacked NF-κB from a typical IFNL1 promoter to the exon-intron region of IFNL1 and decreased the enrichment of RNA polymerase II and H3K27ac, a chromatin accessibility marker, in the promoter region of IFNL1 during IAV infection, consequently reducing IFNL1 gene expression. NS1 deletion enhanced the enrichment of RNA polymerase II at the IFNL1 promoter and promoted its expression.ConclusionOverall, NS1 hijacked NF-κB to prevent its interaction with the IFNL1 promoter and restricted the open chromatin architecture of the promoter, thereby abating antiviral gene expression.

Anti - Inflammatory Activity of Quercetin and Kaempferol Is Limited to Tlr4 Stimulation in Monocytes

Flavonoids are known to exert anti-inflammatory activity but their mechanism at receptor level and their comparative potencies are less studied. Objective of the study is to evaluate, rank order few flavonoids for their cytokine inhibitory activity in monocytes (THP-1) and explore the inhibitory signature among toll-like receptors (TLRs). We tested flavonoids for their potential to inhibit LPS induced cytokines IL-6, TNF alpha in human monocyte cell line THP-1 and mouse macrophage cell line using Enzyme linked immunosorbent assay (ELISA) assays. Quercetin and Kaempferol reduced LPS induced cytokine secretion in monocyte and macrophage cell lines. Quercetin and Kaempferol demonstrated dose dependent inhibition of cytokines IL-6 and TNF alpha. Quercetin demonstrated IC50 of 6.9µM whereas Kaempferol demonstrated IC50 of 14.3µM in cytokine reduction. In THP-1, NF-kB activity is measured using secreted embryonic alkaline phosphatase (SEAP) reporter with different toll-like receptor activation. TLR4 stimulated NF-kB activity was inhibited by Quercetin and Kaempferol in THP-1 cell line, while these flavonoids did not impact signaling of other TLR ligands Pam3CSK4 (TLR1/2) FLS (TLR2/6), Flagellin (TLR5) and R848 (TLR7/8). I. Quercetin and Kaempferol modulate NF-kB activity when stimulated with TLR4, but not with TLR1/2, TLR2/6, TLR5 and TLR7/8 in Monocytes. Understanding the inhibition profile of flavonoids against Toll receptors will help in design better inhibitor which can alleviate inflammatory diseases

Abstract 1732: Nanoparticle delivery of cancer-activated DNA enables the detection and localization of tumors in mice

Abstract The expression of synthetic biomarkers from genetic constructs represents a new paradigm of molecular diagnostic tools for early cancer detection and localization. One of the limitations of liquid biopsy approaches is the low abundance of endogenous biomarkers shed in early-stage disease. To overcome this, Earli’s platform instead uses genetic constructs to force tumors to produce cancer-activated synthetic biomarkers. Thus, technologies that deliver DNA to tumor cells in multiple tissues need to be developed. While non-viral delivery systems such as lipid nanoparticles (LNPs) have achieved clinical success for RNA, the delivery of DNA to tumor cells remains a challenge. We have engineered two classes of nanoparticles using biodegradable and ionizable cationic materials. The efficacy of these nanoparticles to deliver a DNA nanoplasmid containing a cancer-activated promoter to drive expression of a secreted embryonic alkaline phosphatase (SEAP) was evaluated in multiple cell-derived xenograft (CDX) models. The first class of nanoparticles was comprised of poly-beta-amino-ester polymers (PBAEs). Systematic screening of a library of PBAEs and optimization of PEG-lipid content produced nanoparticles approximately 80-100 nm in diameter with slightly positive zeta potential, enabling biodistribution to mouse lung tissues. Testing of initial nanoparticle compositions identified safe and effective formulations that produced 5-fold higher SEAP expression levels in lung tumor-bearing animals versus naïve mice. Further enhancements produced SEAP levels up to 250-fold higher in tumor-bearing versus control mice but resulted in significant increases in liver enzymes, suggesting tolerability issues that are currently being addressed by improving the polymer and formulation composition. The second class of nanoparticles was composed of ionizable lipids such as DLin-MC3-DMA that have been clinically validated for RNA delivery to the liver. Optimized compositions with helper lipid and PEG-lipid variants identified formulations that could successfully deliver DNA to the liver. These formulations produced 30-fold higher SEAP expression in tumor-bearing animals compared to naïve controls in an H1299 CDX model. A 7-fold difference in SEAP levels was demonstrated in an orthotopic Hep3B CDX model between tumor versus non-tumor bearing animals. Strikingly, LNP delivery of a cancer-activated Renilla luciferase construct produced tumor-specific bioluminescence, demonstrating the ability of the LNPs to localize liver tumors. LNP formulations were well tolerated, producing transient, mild to moderate elevations in liver enzymes one day after administration that subsequently resolved. These potent and safe nanoparticle delivery systems are promising agents for enabling future clinical translation of our synthetic biomarker platform. Citation Format: Badri Ananthanarayanan, Regina Nieu, Weihang Ji, Blaine McCarthy, Shengshuang Zhu, Alex Harwig, Maggie C. Louie, David Suhy. Nanoparticle delivery of cancer-activated DNA enables the detection and localization of tumors in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1732.

Abstract 3382: Detection of cancer in dogs using a novel genetic-based synthetic biomarker platform

Abstract Early detection of cancer is an important driver of increased survival, quality of life and reduced healthcare costs. Although liquid biopsy provides a new option for early cancer detection, the limitations of detecting a few molecules of blood-based biomarkers naturally shed by the cancer remain. Earli is developing a highly sensitive, orthogonal approach that uses a genetic construct that usurps dysregulated pathways and actively forces cancer cells to drive the expression of a detectable ‘synthetic’ biomarker. We previously used murine xenograft models to validate the tumor detection properties of EARLI-001, a circular DNA containing a human derived cancer-activated promoter to drive the transient expression of secreted embryonic alkaline phosphatase (SEAP), a protein normally expressed only during fetal development. Biodistribution following intravenous (IV) administration of EARLI-001 shows a broad tissue tropism, enabling the potential to monitor multiple tissues for malignant cells. A single dose of EARLI-001 administered in a pulmonary metastatic cancer mouse model resulted in a 95-fold increase in serum SEAP compared to healthy controls. Recognizing the inherent limitations of murine models, we evaluated EARLI-001 in canines diagnosed with cancer. Dog cancers share many features with human malignancies including spontaneous tumor formation, heterogeneity, growth kinetics, histology, and comparable dysregulated genetic pathways. Furthermore, the use of dogs allows the study of EARLI-001 in an immune competent setting and with substantially increased size (up to 65 kg) comparable to scaling into human subjects. EARLI-001 was first tested for safety and biodistribution in 54 purpose-bred beagles in MTD and GLP toxicology studies which reveal that it is safe and well tolerated across a broad range of clinical doses. Biodistribution analysis in 12 tissues showed nanoplasmid levels peaking in the first days post dose and rapidly decreased to background levels by 60 days. These non-tumor bearing dogs showed no serum SEAP signal at all doses. Following IACUC approval and informed owner consent, EARLI-001 was administered to companion dogs in a standard 3 x 3 dose escalation study, with an expanded mid-range cohort. These companion dogs harbored a wide variety of spontaneous tumors in different tissues of origin. In tumor bearing dogs, EARLI-001 elicited a clear and discernable cancer-activated SEAP signal in 1 of 3 dogs dosed at 0.01 mg/kg, 3 of 6 dosed at 0.03 mg/kg, 2 of 2 at 0.07 mg/kg and 8 of 8 dogs dosed at 0.1 mg/kg. Furthermore, the MTD was not reached, and no significant dose-limiting toxicity was observed in these older, disease-burdened animals. These results show the utility of the platform to interrogate tumor biology and detect the presence of malignancies in relevant in vivo models and provided the critical safety and efficacy data towards a first-in-human clinical study in lung cancer initiated in 2021. Citation Format: Regina Nieu, Emily Phenix, Jennifer Hauss, Hadley Hanson, Nga Ho, Alex Harwig, Shireen Rudina, Badri Ananthanarayanan, Hong Chang, Bijee George, Maggie C. Louie, Julie Bulman-Fleming, Michael Kent, David Suhy. Detection of cancer in dogs using a novel genetic-based synthetic biomarker platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3382.

A Candidate Drug Screen Strategy: The Discovery of Oroxylin A in Scutellariae Radix Against Sepsis via the Correlation Analysis Between Plant Metabolomics and Pharmacodynamics.

Sepsis is an acute systemic infectious disease with high mortality, which urgently needs more effective treatment. Scutellariae radix (SR), a commonly used traditional Chinese medicine (TCM) for clearing heat and detoxification, contains rich natural products possessing anti-inflammatory activity. In previous studies, it was found that the anti-inflammatory activities of SR extracts from different ecological conditions varied wildly. Based on this, in the present study, a screening strategy of antisepsis active components from SR based on correlation analysis between plant metabolomics and pharmacodynamics was established, and the mechanism was explored. First of all, a mass spectrum database of SR (above 240 components) was established to lay the foundation for the identification of plant metabolomics by liquid chromatography tandem mass spectrometry (LC–MS/MS). Through the correlation analysis between plant metabolomics and anti-inflammatory activity of SR from different ecology regions, 10 potential components with high correlation coefficients were preliminarily screened out. After the evaluation of anti-inflammatory activity and toxicity at the cellular level, the pharmacodynamic evaluation in vivo found that oroxylin A had the potentiality of antisepsis both in LPS- and CLP-induced endotoxemia mice. Network pharmacology and Western blot (WB) results indicated that oroxylin A significantly inhibited the toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-κB) signaling pathway, which was further confirmed by secreted embryonic alkaline phosphatase (SEAP) assay. Moreover, the molecular docking analysis indicated that oroxylin A might competitively inhibit LPS binding to myeloid differentiation 2 (MD-2) to block the activation of TLR4. The study provided a feasible research strategy for the screening and discovery of antisepsis candidate drugs from TCM.

FC020: The Uraemic Toxin Indoxyl Sulfate is an Activator Of Caspase-4 but not of Caspase-1 in Monocyte-Like THP-1 Cells

Abstract BACKGROUND AND AIMS Among the plethora of uraemic toxins the protein-bound indoxyl sulphate (IS) plays a prominent role in cardiovascular and renal disease progression. IS also appears to be involved in programmed cell death pathways. Regarding the high inflammatory pyroptosis rates in blood cells of haemodialysis patients (HD), there is the question of whether IS can induce caspase-1 and/or caspases-4/-5, thus triggering pyroptosis-related pathways and the release of proinflammatory interleukin IL-1ß in monocytes. METHOD IS-related effects were investigated in the monocytic cell line THP-1. Differentiated THP-1 (100 nM PMA) cells were used to study IS effects in macrophages. IS concentrations in the range of 1 to 4 mM were applied to reveal putative mechanistic effects mediated by IS. Caspase-1, -4 and -5 specific substrates were used to analyse the different caspase activities by flow-cytometry and luminometric assays. IL-1ß activity of THP-1 supernatants was measured in the HEK-Blue™ IL-1ß cell line, which produces secreted embryonic alkaline phosphatase (SEAP) upon induction with active IL-ß. RESULTS Flow cytometric analysis demonstrates that pyroptosis (AAD+/caspase-1+) is already increased by the stimulation of THP-1 cells at concentrations of 1 mM IS, a concentration which can be found in HD patients with high IS load. These data were confirmed by a second luminometric assay, which is based on a different caspase-1 specific substrate compared with the flow-cytometric assay (Ac-WEHD-aminoluciferin versus FAM-YVAD-FMK). Further, the caspase-1 activity could be enhanced by supplementing IS-stimulated (2 mM) samples with the caspase-1-dependent NLRP3 inflammasome activator nigericin (21 µM). Taking in mind that especially FAM-YVAD-FMK substrate can be cleaved by caspase-1 and caspase-4/-5, we examined the specificity of the tested substrate using inhibitor probes. Supplementing cells with the caspase-1 specific inhibitor Ac-YVAD-CHO (2 µM), we failed to inhibit IS-mediated effects, whereas the nigericin-driven effect could be blocked. However, the addition of the inhibitory substrate Ac-LEVD-CHO (2µM), which specifically blocks caspase-4 and -5 activities totally decreased IS-derived caspase activity (Control: 100%, IS: 128 ± 12%, IS + Ac-LEVD: 81 ± 22%, IS + AC-YVAD: 107 ± 15%; IS versus IS + Ac-LEVD, P &amp;lt; .001). It is known that IS has a stimulating impact on mRNA expression of pro-IL-1ß in macrophage-like THP-1 cells. When differentiated THP-1 cells were stimulated with 4 mM IS for 24-h we found a two-fold increase in IL-1ß mRNA expression. Further, we find a significant increase in caspase-1 and caspase-4 in these cells. However, IL-1ß protein levels seem to be only marginally elevated in IS stimulated samples. Analysing the biological activity of the THP-1 derived supernatants in the HEK-Blue™ IL-1ß cell line, we did not find a SEAP increase in samples stimulated with the IS-derived THP-1 supernatants. CONCLUSION Analysing the effects of indoxyl sulphate in the THP-1 model systems we provide evidence for the first time that the inflammatory caspase-4 and/or caspase-5 is activated in monocyte-like cells without increasing IL-1ß levels. Therefore, one can conclude that IS is not an archetypical NLRP3 inflammasome activator but may contribute to cell death via caspase-4 activation.

A63 THE COLONIC PATHOGEN, ENTAMOEBA HISTOLYTICA ACTIVATES CASPASE-4 IN HUMAN MACROPHAGES THAT CLEAVES GASDERMIN D TO FACILITATE IL-1β SECRETION IN THE ABSENCE OF CELL DEATH

BackgroundA hallmark of Entamoeba histolytica ( Eh) invasion in the gut is acute intestinal inflammation dominated by the secretion of pro-inflammatory cytokines. Live Eh in contact with macrophages activates caspase-1 by the recruitment of the NLRP3 inflammasome in a Gal-lectin and Eh cysteine proteases 5 ( EhCP-A5)-dependent manner, resulting in the maturation and secretion of IL-1β. Eh in contact with macrophages also activates caspase-4 by outside-in signaling but it is unclear how Eh-induced caspase-1/4 regulates gasdermin D (GSDMD) cleavage to drive both pore formation and IL-1β secretion without causing cell death. In this study, we interrogated the requirements and mechanism of Eh-induced caspase-4 activation in cleaving GSDMD to mediate bioactive IL-1β release.AimsHypothesis: Eh-induced activation of caspase-4 regulates GSDMD mediated pro-inflammatory responses.Specific aim: To quantify caspase-1/4 cleavage of GSDMD in Eh-induced pro-inflammatory responses.MethodsHuman PMA-differentiated THP-1 macrophages were used for Eh-macrophage studies. Caspase-1/4 activation and GSDMD cleavage were detected by immunoblot analysis. Bioactive IL-1β secretion was quantified by HEK-BlueTM IL-1β reporter cells via the measurement of secreted embryonic alkaline phosphatase (SEAP) and cell pyroptosis (inflammatory cell death) was determined by LDH assay. Immunoprecipitation was performed in HEK 293T cells transfected with human GSDMD plasmid followed by in vitro caspase cleavage assay.ResultsUnlike caspase-1, Eh-induced caspase-4 activation and IL-1β secretion was independent of the NLRP3 inflammasome as revealed with the use of CRISPR-Cas9 gene edited caspase-1, 4, ASC and NLRP3 macrophages. In the absence of caspase-1, caspase-4 activation was significantly upregulated that promoted the cleavage of GSDMD to induce robust IL-1β secretion. Eh-induced caspase-4 played a major role in triggering IL-1β release and GSDMD pore formation as quantified by SEAP assay and immunoprecipitation of overexpressed GSDMD in HEK 293T cells followed by in vitro caspase cleavage assay. Pharmacological inhibition of GSDMD pore formation and in CRISPR-Cas9 gene edited GSDMD macrophages, Eh-induced IL-1β secretion was highly dependent on GSDMD pore formation and independent of pyroptosis. This was in marked contrast to the positive control, LPS + Nigericin that induced high expression of caspase-1 but not caspase-4 that enhanced GSDMD cleavage and IL-1β secretion and induced massive pyroptosis.ConclusionsThese results suggest that Eh induced a state of “hyperactivated macrophages” that led to caspase-4 dependent GSDMD cleavage and IL-1β secretion in the absence of pyroptosis important in disease pathogenesis.Funding AgenciesNSERC

Importance of cortactin for efficient epithelial NF-ĸB activation by Helicobacter pylori, Salmonella enterica and Pseudomonas aeruginosa, but not Campylobacter spp.

Transcription factors of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) family control important signaling pathways in the regulation of the host innate immune system. Various bacterial pathogens in the human gastrointestinal tract induce NF-κB activity and provoke proinflammatory signaling events in infected epithelial cells. NF-κB activation requires the phosphorylation-dependent proteolysis of inhibitor of κB (IκB) molecules including the NF-κB precursors through ubiquitin-mediated proteolysis. The canonical NF-κB pathway merges on IκB kinases (IKKs), which are required for signal transduction. Using CRISPR-Cas9 technology, secreted embryonic alkaline phosphatase (SEAP) reporter assays and cytokine enzyme-linked immunosorbent assay (ELISA), we demonstrate that the actin-binding protein cortactin is involved in NF-κB activation and subsequent interleukin-8 (IL-8) production upon infection by Helicobacter pylori, Salmonella enterica and Pseudomonas aeruginosa. Our data indicate that cortactin is needed to efficiently activate the c-Sarcoma (Src) kinase, which can positively stimulate NF-κB during infection. In contrast, cortactin is not involved in activation of NF-κB and IL-8 expression upon infection with Campylobacter species C. jejuni, C. coli or C. consisus, suggesting that Campylobacter species pluralis (spp.) induce a different signaling pathway upstream of cortactin to trigger the innate immune response.

305 Usefulness of CHA2DS2-VASc scoring system for predicting risk of embolism in patients with cardiac tumours: a single-centre study

Abstract Aims The link between pro-protein convertase subtilisin/kexin 9 (PCSK9) and inflammatory-related disease has been supported in several experimental and human studies, which show how the protein could acts independent its canonical mechanism, by activation of inflammatory, apoptotic and immune pathways. Among these, TLR4/NFKB signalling pathway has been found to be one of the main pathways mediating the PCSK9-induced increase of pro-inflammatory and pro-thrombotic molecules, such as TNF-alpha, IL-6, IL-1, MCP-1, and TF. To investigate the direct involvement of hTLR4 in recognition of exogenous human recombinant (hr) PCSK9. Methods and results Experiments were carried out in three cell line: (i) HEK293-hTLR4-GFP cell lines obtained by stable co-transfection of HEK293 cells with the pUNO1-hTLR4-GFP, a plasmid expressing the hTLR4 gene fused to a GFP gene; (ii) HEK293-hTLR4+ cells obtained by co-transfection of hTLR4 receptor and its accessory proteins MD-2 and CD14, and an inducible secreted embryonic alkaline phosphatase (SEAP) reporter gene; (iii) HEK293-Null2 cells, a cell line lacking TLR4 expression, used as negative control. NFkB activity were measured by the SEAP reporter gene assay using a fluorescence detection method, while localization of hTLR4 and exogenous hrPCSK9 by confocal microscopy. hrPCSK9 (1 µg/mL) activates NFkB in HEK293-hTLR4+ cells [SEAP activity-OD 620 nm: from a baseline of 0.18 ± 0.06 to 0.68 ± 0.05 (N = 8), P &amp;lt; 0.001] to an extent comparable to lipopolysaccharide, the specific agonist of TLR4. Co-localization of hrPCSK9 and TLR4s was clearly documented by quantitative confocal microscopy in HEK293-hTLR4-GFP cell line, that comprises the analysis of more than 80 fields in ∼2.105 cells/well and showing a percentage of co-localization of ∼4% in membrane spots (P &amp;lt; 0.01). Conclusions Our data support the results reported in previous studies that attribute to PCSK9 a pathophysiological role in development of chronic inflammation and related-diseases such as atherothrombosis. A behavior that extends far beyond LDLR degradation, via a mechanism that might be mediated at least in part by recognition of PCSK9 by the TLRs and later activation of NFkB intracellular pathway. Future studies will be important to better investigate the specific binding site engaged in the PCSK9-TLR interaction and to discriminate the intracellular transduction pathways involved in this response, in order to provide a theoretical basis for the development of innovative therapeutic strategies.

306 Involvement of toll-like receptor 4 in PCSK9-mediated biological effects in cell culture models

Abstract Aims The link between pro-protein convertase subtilisin/kexin 9 (PCSK9) and inflammatory-related disease was supported in several experimental and human studies, which show how the protein could acts independent its canonical mechanism, by activation of inflammatory, apoptotic and immune pathways. Among these, TLR4/NFKB signalling pathway was found to be one of the main pathways mediating the PCSK9-induced increase of pro-inflammatory and pro-thrombotic molecules, such as TNF-alpha, IL-6, IL-1, MCP-1, and TF. To investigate the direct involvement of hTLR4 in recognition of exogenous human recombinant (hr) PCSK9. Methods Experiments were carried out in three cell line: (i) HEK293-hTLR4-GFP cell lines obtained by stable co-transfection of HEK293 cells with the pUNO1-hTLR4-GFP, a plasmid expressing the hTLR4 gene fused to a GFP gene; (ii) HEK293-hTLR4+ cells obtained by co-transfection of hTLR4 receptor and its accessory proteins MD-2 and CD14, and an inducible secreted embryonic alkaline phosphatase (SEAP) reporter gene; (iii) HEK293-Null2 cells, a cell line lacking TLR4 expression, used as negative control. NFkB activity were measured by the SEAP reporter gene assay using a fluorescence detection method, while localization of hTLR4 and exogenous hrPCSK9 by confocal microscopy. Results hrPCSK9 (1 µg/mL) activates NFkB in HEK293-hTLR4+ cells [SEAP activity-OD 620 nm: from a baseline of 0.18 ± 0.06 to 0.68 ± 0.05 (N = 8), P &amp;lt; 0.001] to an extent comparable to Lipopolysaccharide (LPS), the specific agonist of TLR4. Colocalization of hrPCSK9 and TLR4s was clearly documented by quantitative confocal microscopy in HEK293-hTLR4-GFP cell line, that comprises the analysis of more than 80 fields in ∼2.105 cells/well and showing a percentage of co-localization of ∼4% in membrane spots (P &amp;lt; 0.01). Conclusions Our data support the results reported in previous studies that attribute to PCSK9 a pathophysiological role in development of chronic inflammation and related-diseases such as atherothrombosis. A behaviour that extends far beyond LDLR degradation, via a mechanism that might be mediated at least in part by recognition of PCSK9 by the TLRs and later activation of NFKB intracellular pathway. Future studies will be important to better investigate the specific binding site engaged in the PCSK9-TLR interaction and to discriminate the intracellular transduction pathways involved in this response, in order to provide a theoretical basis for the development of innovative therapeutic strategies.