Overexpression Of Adhesion Molecules Research Articles

Poly (ADP-ribose) Polymerase-1 modulations in the genesis of thrombosis.

Thrombosis, a coagulation disorder, occurs due to altered levels of coagulation, fibrinolytic and immune factors, which are otherwise known to maintain hemostasis in normal physiological conditions. Here, we review the direct and indirect participation of a multifunctional nuclear enzyme poly (ADP-ribose) polymerase-1 (PARP1) in the expression of key genes and cellular processes involved in thrombotic pathogenesis. PARP1 biological activities range from maintenance of genomic integrity, chromatin remodeling, base excision DNA repair, stress responses to cell death, angiogenesis and cell cycle pathways. However, under homeostatic imbalances, PARP1 activities are linked with the pathogenesis of diseases, including cancer, aging, neurological disorders, and cardiovascular diseases. Disease-associated distressed cells employ a variety of PARP-1 functions such as oxidative damage exacerbations, cellular energetics and apoptosis pathways, regulation of inflammatory mediators, promotion of endothelial dysfunction, and ERK-mediated signaling in pathogenesis. Thrombosis is one such pathogenesis that comprises exacerbation of coagulation cascade due to biochemical alterations in endothelial cells, platelet activation, overexpression of adhesion molecules, cytokines release, and leukocyte adherence. Thus, the activation of endothelial and inflammatory cells in thrombosis implicates a potential role of PARP1 activation in thrombogenesis. This review article explores the direct impact of PARP1 activation in the etiology of thrombosis and discusses PARP1-mediated endothelial dysfunction, inflammation, and epigenetic regulations in the disease manifestation. Understanding PARP1 functions associated with thrombosis may elucidate novel pathogenetic mechanisms and help in better disease management through newer therapeutic interventions targeting PARP1 activity.

The Interplay between Liver Sinusoidal Endothelial Cells, Platelets, and Neutrophil Extracellular Traps in the Development and Progression of Metabolic Dysfunction-Associated Steatotic Liver Disease.

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a societal burden due to the lack of effective treatment and incomplete pathophysiology understanding. This review explores the intricate connections among liver sinusoidal endothelial cells (LSECs), platelets, neutrophil extracellular traps (NETs), and coagulation disruptions in MASLD pathogenesis. In MASLD's early stages, LSECs undergo capillarization and dysfunction due to excessive dietary macronutrients and gut-derived products. Capillarization leads to ischemic changes in hepatocytes, triggering pro-inflammatory responses in Kupffer cells (KCs) and activating hepatic stellate cells (HSCs). Capillarized LSECs show a pro-inflammatory phenotype through adhesion molecule overexpression, autophagy loss, and increased cytokines production. Platelet interaction favors leucocyte recruitment, NETs formation, and liver inflammatory foci. Liver fibrosis is facilitated by reduced nitric oxide, HSC activation, profibrogenic mediators, and increased angiogenesis. Moreover, platelet attachment, activation, α-granule cargo release, and NETs formation contribute to MASLD progression. Platelets foster fibrosis and microthrombosis, leading to parenchymal extinction and fibrotic healing. Additionally, platelets promote tumor growth, epithelial-mesenchymal transition, and tumor cell metastasis. MASLD's prothrombotic features are exacerbated by insulin resistance, diabetes, and obesity, manifesting as increased von Willebrand factor, platelet hyperaggregability, hypo-fibrinolysis, and a prothrombotic fibrin clot structure. Improving LSEC health and using antiplatelet treatment appear promising for preventing MASLD development and progression.

Targeting CD44 Receptor Pathways in Degenerative Joint Diseases: Involvement of Proteoglycan-4 (PRG4).

Rheumatoid arthritis (RA), osteoarthritis (OA), and gout are the most prevalent degenerative joint diseases (DJDs). The pathogenesis underlying joint disease in DJDs remains unclear. Considering the severe toxicities reported with anti-inflammatory and disease-modifying agents, there is a clear need to develop new treatments that are specific in their effect while not being associated with significant toxicities. A key feature in the development of joint disease is the overexpression of adhesion molecules, e.g., CD44. Expression of CD44 and its variants in the synovial tissues of patients with DJDs is strongly associated with cartilage damage and appears to be a predicting factor of synovial inflammation in DJDs. Targeting CD44 and its downstream signaling proteins has emerged as a promising therapeutic strategy. PRG4 is a mucinous glycoprotein that binds to the CD44 receptor and is physiologically involved in joint lubrication. PRG4-CD44 is a pivotal regulator of synovial lining cell hemostasis in the joint, where lack of PRG4 expression triggers chronic inflammation and fibrosis, driven by persistent activation of synovial cells. In view of the significance of CD44 in DJD pathogenesis and the potential biological role for PRG4, this review aims to summarize the involvement of PRG4-CD44 signaling in controlling synovitis, synovial hypertrophy, and tissue fibrosis in DJDs.

Abstract P318: INDOLE-3 ACETIC ACID: A NOVEL DUAL-ACTION INHIBITOR OF THE ENDOTHELIN SYSTEM FOR TREATING HYPERTENSION

Elevated levels of endothelin-1 (ET-1) stimulate potent vasoconstriction, free radical production, oxidative stress, and vascular inflammation, which are often present in salt-sensitive hypertension, pulmonary hypertension, drug-resistant hypertension, and hypertension among African Americans. There is currently no known drug that simultaneously targets both ET-1 receptors (ETRs) and the ET-1 synthesizing enzyme ECE-1, even though dual targeting of the ET system could lead to a new generation of drug molecules with improved therapeutic outcome. Using an integrated in vitro, in vivo and in silico approaches, here we report the discovery of indole-3 acetic acid (IAA) as an inhibitor of both ET-1 receptors and ECE-1. IAA is produced in the human body via tryptophan metabolism by gut microbiota. Our data demonstrates that IAA concentration-dependently inhibits ET-1-evoked vasoconstriction in rat resistance mesenteric arteries and ET-1-stimulated reactive oxygen species (ROS) production in smooth muscle cells (SMCs). Furthermore, IAA suppresses ET-1-induced endothelial cell (EC) activation, adhesion molecule overexpression, and leukocyte adhesion. IAA inhibits ET-1-stimulated, ET A R- and ET B R-mediated increases in [Ca 2+ ] i . Intriguingly, IAA produces a concentration-dependent inhibition of purified human ECE-1. Treatment of Dahl salt-sensitive (DSS) hypertensive rats, a model of augmented ET-1 signaling, with an oral extended-release formulation of IAA significantly inhibits blood pressure elevation in high-salt diet-fed (HSD) DSS rats. IAA-treated DSS arteries show intact acetylcholine- and sodium nitroprusside-induced vasodilation, suggesting that IAA preserves endothelial and smooth muscle function, respectively. IAA treatment also prevents arterial remodeling, oxidative stress, and kidney dysfunction in HSD DSS rats. Overall, our study identifies IAA as the first-in-class dual-action inhibitor of ETRs and ECE-1, which produces profound antihypertensive effect in vivo. IAA could also be therapeutically useful for other cardiovascular diseases in which ET-1 signaling is implicated.

Oxidative Stress Management in Cardiorenal Diseases: Focus on Novel Antidiabetic Agents, Finerenone, and Melatonin.

Oxidative stress is characterized by excessive production of reactive oxygen species together with exhausted antioxidant defenses. This constitutes a main pathophysiologic process that is implicated in cardiovascular and renal diseases. In particular, enhanced oxidative stress may lead to low-density lipoprotein accumulation and oxidation, endothelial cell activation, adhesion molecule overexpression, macrophage activation, and foam cell formation, promoting the development and progression of atherosclerosis. The deleterious kidney effects of oxidative stress are numerous, including podocytopathy, mesangial enlargement, renal hypertrophy, tubulointerstitial fibrosis, and glomerulosclerosis. The prominent role of oxidative mechanisms in cardiorenal diseases may be counteracted by recently developed pharmacotherapies such as novel antidiabetic agents and finerenone. These agents have demonstrated significant antioxidant activity in preclinical and clinical studies. Moreover, the use of melatonin as a treatment in this field has been experimentally investigated, with large-scale clinical studies being awaited. Finally, clinical implications and future directions in this field are presented.

Rosmarinic acid downregulates the oxLDL‑induced interaction between monocytes and endothelial cells, in addition to monocyte diapedesis, under high glucose conditions.

Endothelial dysfunction during diabetes has been previously reported to be at least in part attributed to increased oxidized low-density lipoprotein (oxLDL) levels mediated by high glucose (HG) levels. Endothelial inflammation increases the adhesiveness of monocytes to the endothelium in addition to increasing vascular permeability, promoting diabetic atherogenesis. In a previous study, it was reported that oxLDL treatment induced nucleotide-binding domain and leucine-rich repeat containing family, pyrin domain-containing 3 inflammasome activation in endothelial cells (ECs) under HG conditions, in a manner that could be effectively reversed by rosmarinic acid. However, it remains unclear whether oxLDL-mediated inflammasome activation can regulate the interaction between monocytes and ECs. The effects of oxLDL-mediated inflammasome activation on endothelial permeability under HG conditions, in addition to the effects of rosmarinic acid on these oxLDL-mediated processes, also remain poorly understood. Therefore, the present study aimed to elucidate the mechanisms involved in oxLDL-induced endothelial permeability and monocyte diapedesis under HG conditions, in addition to the potential effects of rosmarinic acid. ECs were treated with oxLDL under HG conditions in the presence or absence of ROS scavengers mitoTEMPO and NAC, p38 inhibitor SB203580, FOXO1 inhibitor AS1842856 or transfected with the TXNIP siRNA, before protein expression levels of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), phosphorylated vascular endothelial-cadherin (VE-cadhedrin), VE-cadherin and zonula occludens-1 (ZO-1) were measured by western blotting. In addition, adhesion assay and Transwell assays were performed. oxLDL was found to significantly increase the expression of ICAM-1 and VCAM-1 in ECs under HG conditions whilst also enhancing the adhesion of monocytes to ECs. This was found to be dependent on the reactive oxygen species (ROS)/p38 MAPK/forkhead box O1 (FOXO1)/thioredoxin interacting protein (TXNIP) signaling pathway. In addition, oxLDL-stimulated ECs under HG conditions exhibited increased phosphorylated VE-cadherin protein levels and decreased ZO-1 protein expression levels compared with those in untreated ECs, suggesting increased endothelial permeability. Furthermore, monocyte transmigration through the endothelial monolayer was significantly increased by oxLDL treatment under HG conditions. These oxLDL-mediated effects under HG conditions were also demonstrated to be dependent on this ROS/p38 MAPK/FOXO1/TXNIP signaling pathway. Subsequently, rosmarinic acid treatment significantly reversed oxLDL-induced overexpression of adhesion molecules and monocyte-EC adhesion, oxLDL-induced endothelial junction hyperpermeability and monocyte transmigration through the endothelial monolayer under HG conditions, in a dose-dependent manner. These results suggest that rosmarinic acid can exert a protective effect against oxLDL-mediated endothelial dysfunction under HG conditions by reducing the interaction between monocytes and ECs in addition to preventing monocyte diapedesis.

Junctional adhesion molecule C expression specifies a CD138low/neg multiple myeloma cell population in mice and humans

AbstractDeregulation such as overexpression of adhesion molecules influences cancer progression and survival. Metastasis of malignant cells from their primary tumor site to distant organs is the most common reason for cancer-related deaths. Junctional adhesion molecule-C (JAM-C), a member of the immunoglobulin-like JAM family, can homodimerize and aid cancer cell migration and metastasis. Here we show that this molecule is dynamically expressed on multiple myeloma (MM) cells in the bone marrow and co-localizes with blood vessels within the bone marrow of patients and mice. In addition, upregulation of JAM-C inversely correlates with the downregulation of the canonical plasma cell marker CD138 (syndecan-1), whose surface expression has recently been found to dynamically regulate a switch between MM growth in situ and MM dissemination. Moreover, targeting JAM-C in a syngeneic in vivo MM model ameliorates MM progression and improves outcome. Overall, our data demonstrate that JAM-C might serve not only as an additional novel diagnostic biomarker but also as a therapeutic target in MM disease.

Derivation and characterisation of endothelial cells from patients with chronic thromboembolic pulmonary hypertension

Pulmonary endarterectomy (PEA) resected material offers a unique opportunity to develop an in vitro endothelial cell model of chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to comprehensively analyze the endothelial function, molecular signature, and mitochondrial profile of CTEPH-derived endothelial cells to better understand the pathophysiological mechanisms of endothelial dysfunction behind CTEPH, and to identify potential novel targets for the prevention and treatment of the disease. Isolated cells from specimens obtained at PEA (CTEPH-EC), were characterized based on morphology, phenotype, and functional analyses (in vitro and in vivo tubule formation, proliferation, apoptosis, and migration). Mitochondrial content, morphology, and dynamics, as well as high-resolution respirometry and oxidative stress, were also studied. CTEPH-EC displayed a hyperproliferative phenotype with an increase expression of adhesion molecules and a decreased apoptosis, eNOS activity, migration capacity and reduced angiogenic capacity in vitro and in vivo compared to healthy endothelial cells. CTEPH-EC presented altered mitochondrial dynamics, increased mitochondrial respiration and an unbalanced production of reactive oxygen species and antioxidants. Our study is the foremost comprehensive investigation of CTEPH-EC. Modulation of redox, mitochondrial homeostasis and adhesion molecule overexpression arise as novel targets and biomarkers in CTEPH.

Inflammatory Mechanisms Contributing to Endothelial Dysfunction.

Maintenance of endothelial cell integrity is an important component of human health and disease since the endothelium can perform various functions including regulation of vascular tone, control of hemostasis and thrombosis, cellular adhesion, smooth muscle cell proliferation, and vascular inflammation. Endothelial dysfunction is encompassed by complex pathophysiology that is based on endothelial nitric oxide synthase uncoupling and endothelial activation following stimulation from various inflammatory mediators (molecular patterns, oxidized lipoproteins, cytokines). The downstream signaling via nuclear factor-κB leads to overexpression of adhesion molecules, selectins, and chemokines that facilitate leukocyte adhesion, rolling, and transmigration to the subendothelial space. Moreover, oscillatory shear stress leads to pro-inflammatory endothelial activation with increased monocyte adhesion and endothelial cell apoptosis, an effect that is dependent on multiple pathways and flow-sensitive microRNA regulation. Moreover, the role of neutrophil extracellular traps and NLRP3 inflammasome as inflammatory mechanisms contributing to endothelial dysfunction has recently been unveiled and is under further investigation. Consequently, and following their activation, injured endothelial cells release inflammatory mediators and enter a pro-thrombotic state through activation of coagulation pathways, downregulation of thrombomodulin, and an increase in platelet adhesion and aggregation owing to the action of von-Willebrand factor, ultimately promoting atherosclerosis progression.

Two Novel PET Radiopharmaceuticals for Endothelial Vascular Cell Adhesion Molecule-1 (VCAM-1) Targeting.

Atherosclerosis is a chronic progressive disease involving inflammatory events, such as the overexpression of adhesion molecules including the endothelial Vascular Cell Adhesion Molecule-1 (VCAM-1). VCAM-1 is rapidly overexpressed in the first stages of atherosclerosis, thus representing a promising target for early atheroma detection. Two novel Positron Emission Tomography (PET) radiopharmaceuticals (MacroP and NAMP), based on the VCAM-1-binding peptide having sequence VHPKQHRGGSKGC, were synthesized and characterized. MacroP is derived from the direct conjugation of a DOTA derivative with the peptide, while NAMP is a biotin derivative conceived to be employed in a three-step pretargeting system, involving the use of a double-chelating derivative of DOTA. The identity of the newly synthesized radiopharmaceuticals was confirmed by mass spectrometry and, after radiolabeling with 68Ga, both showed high radiochemical purity; in vitro tests on human umbilical vein endothelial cells evidenced their VCAM-1 binding ability, with higher radioactive uptake in the case of NAMP. Moreover, NAMP might also be employed in a theranostic approach in association with functionalized biotinylated nanoparticles.

Combination of HIV-1 and Diabetes Enhances Blood Brain Barrier Injury via Effects on Brain Endothelium and Pericytes.

Despite combined antiretroviral therapy (ART) achieving efficient HIV replication control, HIV-associated neurocognitive disorders (HAND) continue to be highly prevalent in HIV-infected patients. Diabetes mellitus (DM) is a well-known comorbidity of HAND in HIV-infected patients. Blood brain barrier (BBB) dysfunction has been linked recently to dementia development, specifically in DM patients. BBB injury exists both in HIV and DM, likely contributing to cognitive decline. However, its extent, exact cellular targets and mechanisms are largely unknown. In this report, we found a decrease in pericyte coverage and expression of tight junction proteins in human brain tissues from HIV patients with DM and evidence of HAND when compared to HIV-infected patients without DM or seronegative DM patients. Using our in vitro BBB models, we demonstrated diminution of barrier integrity, enhanced monocyte adhesion, changes in cytoskeleton and overexpression of adhesion molecules in primary human brain endothelial cells or human brain pericytes after exposure to HIV and DM-relevant stimuli. Our study demonstrates for the first-time evidence of impaired BBB function in HIV-DM patients and shows potential mechanisms leading to it in brain endothelium and pericytes that may result in poorer cognitive performance compared to individuals without HIV and DM.

Effect of Hyperbaric Oxygen on Tissue Damage and Expression of Adhesion Molecules and C3 in a Rat Model of Renal Ischemia-Reperfusion Injury After Kidney Transplantation.

BackgroundThe aim of this study was to investigate the protective effect and mechanism of hyperbaric oxygen (HBO) in a rat model of renal ischemia-reperfusion injury following kidney transplantation.Material/MethodsSprague Dawley rats were randomly divided into 3 groups (n=18): sham group, kidney transplantation group, and HBO treatment group. Six rats in each group were sacrificed at 1, 3, and 5 hours after reperfusion, and serum and renal tissue were then collected. The serum creatinine levels and histopathological changes of the renal tissue were detected. ICAM-1, VCAM-1, and C3 expression levels were also detected by immunohistochemical staining or real-time polymerase chain reaction.ResultsRenal function was damaged in the kidney transplantation group and the HBO treatment group compared with sham group (P<0.05). Renal histopathological changes, including tubular cell swelling, tubular dilatation, and hyaline casts, were remarkably reduced in the HBO treatment group compared to the kidney transplantation group. In the immunohistochemical examination, the expression levels of ICAM-1, VCAM-1, and C3 were obviously increased in the kidney transplantation group and the HBO treatment group; moreover, the levels in the HBO treatment group were significantly lower than in the kidney transplantation group (P<0.05). In addition, the ICAM-1 and C3 mRNA levels were increased in the kidney transplantation group and HBO treatment group, but the levels of in the HBO treatment group them were significantly decreased compared to the kidney transplantation group that at 3 and 5 hours after reperfusion (P<0.05).ConclusionsHBO treatment exerted a protective effect on renal function through inhibition of adhesion molecule overexpression and complement system activation in a rat model of renal ischemia-reperfusion injury after kidney transplantation.

L1 Cell Adhesion Molecule Overexpression Down Regulates Phosphacan and Up Regulates Structural Plasticity-Related Genes Rostral and Caudal to the Complete Spinal Cord Transection

L1 cell adhesion molecule (L1CAM) supports spinal cord cellular milieu after contusion and compression lesions, contributing to neuroprotection, promoting axonal outgrowth, and reducing outgrowth-inhibitory molecules in lesion proximity. We extended investigations into L1CAM molecular targets and explored long-distance effects of L1CAM rostral and caudal to complete spinal cord transection (SCT) in adult rats. L1CAM overexpression in neurons and glia after Th10/Th11 SCT was achieved using adeno-associated viral vector serotype 5 (AAV5) injected into an L1-lumbar segment immediately after transection. At 5 weeks, a L1CAM mRNA profound decrease detected rostral and caudal to the transection site was alleviated by AAV5-L1CAM treatment, with increased endogenous L1CAM rostral to the SCT. Transected corticospinal tract fibers showed attenuated retraction after treatment, accompanied by a multi-segmental increase of lesion-reduced expression of adenylate cyclase 1 (Adcy1), synaptophysin, growth-associated protein 43, and myelin basic protein genes caudal to transection, and Adcy1 rostral to transection. In parallel, chondroitin sulfate proteoglycan phosphacan elevated after SCT was downregulated after treatment. Low-molecular L1CAM isoforms generated after spinalization indicated the involvement of sheddases in L1CAM processing and long-distance effects. A disintegrin and metalloproteinase (ADAM)10 sheddase immunoreactivity, stronger in AAV5-L1CAM than AAV5- enhanced green fluorescent protein (EGFP)-transduced motoneurons indicated local ADAM10 upregulation by L1CAM. The results suggest that increased L1CAM availability and penetration of diffusible L1CAM fragments post-lesion induce both local and long-distance neuronal and glial responses toward better neuronal maintenance, neurite growth, and myelination. Despite the fact that intervention promoted beneficial molecular changes, kinematic analysis of hindlimb movements showed minor improvement, indicating that spinalized rats require longer L1CAM treatment to regain locomotor functions.

Alterations in intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) in human endothelial cells.

Alterations of Endothelial cells (ECs) play a critical role in different pathogenesis of many serious human diseases, and dysfunction of the vascular endothelium is an indicator for human disorders. Endothelial dysfunction is considered to be an early indicator for atherosclerosis, which is characterised by overexpression of adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Hydrogen peroxide (H2O2) released via neutrophils is an important mediator of endothelial cell function. Ambient production of superoxide anion (O2-) and subsequently H2O2 at low levels is critical for regulating endothelial cell functions and proliferation. In this study, we investigated the effects of H2O2 on the expression of adhesion molecules VCAM-1 and ICAM-1 in cultured human umbilical vein endothelial cells (HUVECs). Intracellular superoxide anion production was detected by using p-Nitro Blue Tetrazolium (NBT) assay. Our results showed that administration of 100μM of H2O2 on HUVECs for 2, 6, 12 and 24 h induced a time-dependent increase in ICAM-1 and VCAM-1 mRNA and protein expression levels with a significant increase observed from 6 h. HUVECs exposed to H2O2 exhibit increased O2-, suggesting that H2O2 induced oxidative stress may be a reasonable for atherosclerosis. This increase can be reduced by the flavonoid, N-acetyl cysteine (NAC). The modulation of endothelial cell function through this mechanism may underlie the contribution of H2O2 to the development of vascular disease.

Germline Genetic IKZF1 Variation and Predisposition to Childhood Acute Lymphoblastic Leukemia

Somatic genetic alterations of IKZF1, which encodes the lymphoid transcription factor IKAROS, are common in high-risk B-progenitor acute lymphoblastic leukemia (ALL) and are associated with poor prognosis. Such alterations result in the acquisition of stem cell-like features, overexpression of adhesion molecules causing aberrant cell-cell and cell-stroma interaction, and decreased sensitivity to tyrosine kinase inhibitors. Here we report coding germline IKZF1 variation in familial childhood ALL and 0.9% of presumed sporadic B-ALL, identifying 28 unique variants in 45 children. The majority of variants adversely affected IKZF1 function and drug responsiveness of leukemic cells. These results identify IKZF1 as a leukemia predisposition gene, and emphasize the importance of germline genetic variation in the development of both familial and sporadic ALL.

Overexpression of adhesion molecules and barrier molecules is associated with differential infiltration of immune cells in non-small cell lung cancer

Immunotherapy is emerging as a promising option for lung cancer treatment. Various endothelial adhesion molecules, such as integrin and selectin, as well as various cellular barrier molecules such as desmosome and tight junctions, regulate T-cell infiltration in the tumor microenvironment. However, little is known regarding how these molecules affect immune cells in patients with lung cancer. We demonstrated for the first time that overexpression of endothelial adhesion molecules and cellular barrier molecule genes was linked to differential infiltration of particular immune cells in non-small cell lung cancer. Overexpression of endothelial adhesion molecule genes is associated with significantly lower infiltration of activated CD4 and CD8 T-cells, but higher infiltration of activated B-cells and regulatory T-cells. In contrast, overexpression of desmosome genes was correlated with significantly higher infiltration of activated CD4 and CD8 T-cells, but lower infiltration of activated B-cells and regulatory T-cells in lung adenocarcinoma. This inverse relation of immune cells aligns with previous studies of tumor-infiltrating B-cells inhibiting T-cell activation. Although overexpression of endothelial adhesion molecule or cellular barrier molecule genes alone was not predictive of overall survival in our sample, these genetic signatures may serve as biomarkers of immune exclusion, or resistance to T-cell mediated immunotherapy.

Germline Genetic IKZF1 Variation and Predisposition to Childhood Acute Lymphoblastic Leukemia

IKZF1, which encodes the lymphoid transcription factor IKAROS, is frequently targeted by somatic deletions and mutations in high-risk Bprogenitor acute lymphoblastic leukemia (ALL) and is associated with poor prognosis. Somatic IKZF1 alterations result in the acquisition of stem celllike features, overexpression of adhesion molecules causing aberrant cellcell and cell-stroma interaction, and decreased sensitivity to tyrosine kinase inhibitors. Here we report coding IKZF1 variation in familial childhood ALL and 1% of presumed sporadic B-ALL, with 28 unique germline IKZF1 variants in 45 children. The majority of variants adversely affected IKZF1 function and drug responsiveness of leukemic cells. These results identify IKZF1 as a leukemia predisposition gene, and emphasize the importance of germline genetic variation in the development of both familial and sporadic ALL.

MA 05.11 Endothelial Adhesion Molecule Overexpression Correlates to Decreased CD8 T Cells and Increased B/Treg Cells in Lung Cancer

MA 05.11 Endothelial Adhesion Molecule Overexpression Correlates to Decreased CD8 T Cells and Increased B/Treg Cells in Lung Cancer

Chicoric acid is a potent anti-atherosclerotic ingredient by anti-oxidant action and anti-inflammation capacity.

Atherosclerotic cardiovascular disease is linked to both oxidative stress and endothelial cell dysfunction. Chicoric acid has antioxidant and anti-inflammatory properties. In the present investigation, we demonstrated that chicoric acid inhibits oxidized low-density lipoprotein (oxLDL)-facilitated dysfunction in human umbilical vein endothelial cells (HUVECs). Oxidative injuries were tested by investigating the formation of intracellular reactive oxygen species (ROS) and by examining the activity of antioxidant enzymes and the function of endothelial nitric oxide synthase (eNOS). We also confirmed that chicoric acid mitigates apoptotic features caused by oxLDL, such as the subsequent break down of mitochondrial transmembrane potential and the activation of Bax, which promote DNA strand breaks and activate caspase-3. Moreover, our data revealed that chicoric acid attenuated the oxLDL activation of NF-?B, the attachment of THP-1 cells and the overexpression of adhesion molecules in human endothelial cells. The results of this study suggest a potential molecular mechanism through which chicoric acid inhibits oxLDL-induced human endothelial dysfunction.

Germline Genetic Variation in IKZF1 and Predisposition to Childhood Acute Lymphoblastic Leukemia

Background There is increasing evidence for an inherited predisposition to pediatric acute lymphoblastic leukemia (ALL). We and others have previously reported rare and highly penetrant variants in hematopoietic transcription factors (PAX5 and ETV6) and tumor suppressor genes (TP53) in both sporadic and familial ALL. IKZF1encodes the founding member of the Ikaros family of zinc finger transcription factors, and is a critical regulator of lymphoid development. IKZF1 is frequently targeted by somatic deletions and mutations in high-risk B-ALL, particularly Ph+ and Ph-like ALL, and is associated with poor outcome. IKZF1 alterations have previously been shown to result in the acquisition of stem cell-like features, overexpression of adhesion molecules causing aberrant cell-cell and cell-stroma interaction, and decreased sensitivity to tyrosine kinase inhibitors. Genome-wide association studies have also identified an association between common polymorphisms at the IKZF1locus and risk of developing ALL, however the nature and effects of germline IKZF1variation in the pathogenesis of ALL are poorly understood. In this study, we sought to comprehensively characterize germline IKZF1 genetic variation and to determine the extent to which they contribute to predisposition to ALL.Methods We recently identified a germline frameshift IKZF1 variant (D186fs) in the proband of a family with BCR-ABL1 ALL with incompletely penetrant autosomal dominant inheritance, and carriers of this variant showed varying degree of B cell deficiency. We sequenced IKZF1in germline DNA from 5,008 children with ALL (4902 B-ALL and 106 T-ALL) enrolled on ChildrenÕs Oncology Group and St. Jude ChildrenÕs Res. Hosp. frontline ALL trials. We examined each variant for its effects on transcriptional repression, DNA-binding, cellular localization, homodimerization, and leukemic cell adhesion in mouse BCR-ABL1 Arfnull B-ALL cells and/or in HEK 293T cells. All variants were assayed for their effects on cell viability and proliferation, cell-cell adhesion, and IKZF1 protein expression and localization in BCR-ABL1 Arfnull pre-B cells. Representative variants, including M31V (N-term), H163Y (DNA-binding domain), D186Tfs (familial index), M306* (truncation of C-terminus), and A434G (C-terminus) were also assayed in detail for their ability to dimerize with wild type IKZF1, bind to DNA, or dominant negative effects on transcription repressor activity in HEK293T cells. IKZF1 variants were also evaluated for inducing perturbations in cell adhesion and THY1, ITGA5, SELL expression in the mouse PreB cells, and adhesion within the bone marrow niche by ex vivo imaging of calvaria. Finally, the effects of variants on dasatinib sensitivity were assessedin vitro and in vivo.Results We identified 28 germline IKZF1variants in children with ALL, mostly in B-ALL (Figure 1). Among these variants, 3 were frameshift or nonsense resulting in truncated IKZF1 proteins. Of the remaining missense variants, 2 were located within the N-terminal DNA-binding domain, 1 in the C-terminal dimerization domain, and 22 in other parts of IKZF1 protein with clustering proximal to the C-terminal zinc fingers. In mouse BCR-ABL1 Arfnull pre-B cells, all but 4 variants (P18T, P420Q, H432Q, and M518K) variably perturbed IKZF1 function. In contrast to expression of wild-type IKZF1, which caused growth arrest, 24 of the ALL variants were tolerated; 18 caused cellular aggregation; 15 displayed cytoplasmic mislocalization; and 14 out of 20 variants analyzed had significant upregulation of the adhesion molecules THY1, ITGA5 and/or SELL that are normally repressed by IKZF1. In HEK293T cells, 3 IKZF1 truncating variants showed dramatic loss of transcription repressor activity and no longer dimerized with wildtype IKZF1. DNA-binding domain variants (R162P, H163Y) failed to repress target promoter transcription but also altered wildtype IKZF1 function in a dominant negative fashion. In comprehensively characterization of representative variants (M31V, H163Y, D186Tfs, M306X, and A434G), these variations caused cell-stroma adherence in the bone marrow niche in vivo, and significantly reduced sensitivity of leukemic cells to dasatinib in vitro and in vivo.Conclusions These results identify IKZF1 as a new ALL predisposition gene, and suggest that these germline risk variants have roles in both leukemia pathogenesis and treatment responsiveness. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.