ABSTRACT
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has chemotherapeutic potential as a regulator of an extrinsic apoptotic ligand, but its effect as a drug is limited by innate and acquired resistance. Recent findings suggest that an intermediate drug tolerance could mediate acquired resistance, which has made the main obstacle for limited utility of TRAIL as an anti-cancer therapeutics. We propose miRNA-dependent epigenetic modification drives the drug tolerant state in TRAIL-induced drug tolerant (TDT). Transcriptomic analysis revealed miR-29 target gene activation in TDT cells, showing oncogenic signature in lung cancer. Also, the restored TRAIL-sensitivity was associated with miR-29ac and 140-5p expressions, which is known as tumor suppressor by suppressing oncogenic protein RSK2 (p90 ribosomal S6 kinase), further confirmed in patient samples. Moreover, we extended this finding into 119 lung cancer cell lines from public data set, suggesting a significant correlation between TRAIL-sensitivity and RSK2 mRNA expression. Finally, we found that increased RSK2 mRNA is responsible for NF-κB activation, which we previously showed as a key determinant in both innate and acquired TRAIL-resistance. Our findings support further investigation of miR-29ac and -140-5p inhibition to maintain TRAIL-sensitivity and improve the durability of response to TRAIL in lung cancer.
ABSTRACT
The worldwide appearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has generated significant concern and posed a considerable challenge to global health. Phosphorylation is a common post-translational modification that affects many vital cellular functions and is closely associated with SARS-CoV-2 infection. Precise identification of phosphorylation sites could provide more in-depth insight into the processes underlying SARS-CoV-2 infection and help alleviate the continuing COVID-19 crisis. Currently, available computational tools for predicting these sites lack accuracy and effectiveness. In this study, we designed an innovative meta-learning model, Meta-Learning for Serine/Threonine Phosphorylation (MeL-STPhos), to precisely identify protein phosphorylation sites. We initially performed a comprehensive assessment of 29 unique sequence-derived features, establishing prediction models for each using 14 renowned machine learning methods, ranging from traditional classifiers to advanced deep learning algorithms. We then selected the most effective model for each feature by integrating the predicted values. Rigorous feature selection strategies were employed to identify the optimal base models and classifier(s) for each cell-specific dataset. To the best of our knowledge, this is the first study to report two cell-specific models and a generic model for phosphorylation site prediction by utilizing an extensive range of sequence-derived features and machine learning algorithms. Extensive cross-validation and independent testing revealed that MeL-STPhos surpasses existing state-of-the-art tools for phosphorylation site prediction. We also developed a publicly accessible platform at https://balalab-skku.org/MeL-STPhos. We believe that MeL-STPhos will serve as a valuable tool for accelerating the discovery of serine/threonine phosphorylation sites and elucidating their role in post-translational regulation.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Phosphorylation , SARS-CoV-2/metabolism , Serine/metabolism , Threonine/metabolismABSTRACT
This study examined the effectiveness of the Happy Mother mobile app developed for self-management of postpartum depression, based on cognitive behavioural therapy. A randomized controlled trial, with a pre- and a post-test design, was conducted in South Korea. Effectiveness was analysed using repeated measures ANOVA and Wilcoxon Signed Rank Test. We confirmed that the experimental group performed significantly more health promoting behaviours than the control group (F = 5.15, p = 0.007). However, there was no significant difference in postpartum depression, knowledge of depression, maladaptive beliefs, social support, sleep quality, and stress-coping behaviours between the two groups. The experimental group's mood score increased by 1.79 ± 2.51 points, resulting in significant differences before and after the intervention (Z = -2.81, p = 0.005). The quality of sleep score in the experimental group increased by 1.48 ± 1.70 points and was also significantly different after the intervention (Z = -3.23, p = 0.001). The activity practice rate of the experimental group significantly increased by 30.27 ± 29.27% after using the app (Z = -2.81, p = 0.005). We found the app to be effective in promoting mothers' health behaviour and improving their depressive mood.
ABSTRACT
The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in significant morbidity and mortality worldwide. Despite a successful vaccination programme, the emergence of mutated variants that can escape current levels of immunity mean infections continue. Herein, we report the development of CT-P63, a broad-spectrum neutralizing monoclonal antibody. In vitro studies demonstrated potent neutralizing activity against the most prevalent variants, including Delta and the BA.1 and BA.2 sub-lineages of Omicron. In a transgenic mouse model, prophylactic CT-P63 significantly reduced wild-type viral titres in the respiratory tract and CT-P63 treatment proved efficacious against infection with Beta, Delta, and Omicron variants of SARS-CoV-2 with no detectable infectious virus in the lungs of treated animals. A randomized, double-blind, parallel-group, placebo-controlled, Phase I, single ascending dose study in healthy volunteers (NCT05017168) confirmed the safety, tolerability, and pharmacokinetics of CT-P63. Twenty-four participants were randomized and received the planned dose of CT-P63 or placebo. The safety and tolerability of CT-P63 were evaluated as primary objectives. Eight participants (33.3%) experienced a treatment-emergent adverse event (TEAE), including one grade ≥3 (blood creatine phosphokinase increased). There were no deaths, treatment-emergent serious adverse events, TEAEs of special interest, or TEAEs leading to study drug discontinuation in the CT-P63 groups. Serum CT-P63 concentrations rapidly peaked before declining in a biphasic manner and systemic exposure was dose proportional. Overall, CT-P63 was clinically safe and showed broad-spectrum neutralizing activity against SARS-CoV-2 variants in vitro and in vivo.
Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing , Antibodies, Viral , Broadly Neutralizing Antibodies , Creatine Kinase , Humans , Mice , Spike Glycoprotein, CoronavirusABSTRACT
The recent commercial success of flexible and foldable displays has resulted in growing interest in stretchable electronics which are considered to be the next generation of the optoelectronic technology. Stretchable display technologies are being intensively studied for versatile applications including wearable, attachable, and shape changeable electronics. In this paper, we present high fill factor, stretchable inorganic light-emitting diode (LED) displays fabricated by connecting mini-LEDs and stretchable interconnects in a double-layer modular design. The double-layer modular design enables an increased areal coverage of LEDs and stretchable interconnectors with both electrical and mechanical stability. The main features of the double-layer modular design, fabrication processes, and device characteristics for the high fill factor, stretchable inorganic LED display are discussed, with experimental and computational results. Demonstrations of a passive matrix LED display confirm the potential value of the multi-layer structured, stretchable electronics in a wide range of applications that need high fill factor with high stretchability.
ABSTRACT
The SARS-CoV-2 variant is rapidly spreading across the world and causes to resurge infections. We previously reported that CT-P59 presented its in vivo potency against Beta variants, despite its reduced activity in cell experiments. Yet, it remains uncertain to exert the antiviral effect of CT-P59 on Gamma, Delta and its associated variants (L452R). To tackle this question, we carried out cell tests and animal studies. CT-P59 showed neutralization against Gamma, Delta, Epsilon, and Kappa variants in cells, with reduced susceptibility. The mouse challenge experiments with Gamma and Delta variants substantiated in vivo potency of CT-P59 showing symptom remission and virus abrogation in the respiratory tract. Collectively, cell and animal studies showed that CT-P59 is effective against Gamma and Delta variants infection, hinting that CT-P59 has therapeutic potential for patients infected with Gamma, Delta and its associated variants.
Subject(s)
Antibodies, Monoclonal, Humanized/pharmacology , Antibodies, Neutralizing/pharmacology , COVID-19 Drug Treatment , Disease Models, Animal , Immunoglobulin G/pharmacology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/pharmacology , Body Weight/drug effects , COVID-19/virology , Female , Humans , Mice, Transgenic , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Survival AnalysisABSTRACT
Vaccines and therapeutics are urgently needed for the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we screen human monoclonal antibodies (mAb) targeting the receptor binding domain (RBD) of the viral spike protein via antibody library constructed from peripheral blood mononuclear cells of a convalescent patient. The CT-P59 mAb potently neutralizes SARS-CoV-2 isolates including the D614G variant without antibody-dependent enhancement effect. Complex crystal structure of CT-P59 Fab/RBD shows that CT-P59 blocks interaction regions of RBD for angiotensin converting enzyme 2 (ACE2) receptor with an orientation that is notably different from previously reported RBD-targeting mAbs. Furthermore, therapeutic effects of CT-P59 are evaluated in three animal models (ferret, hamster, and rhesus monkey), demonstrating a substantial reduction in viral titer along with alleviation of clinical symptoms. Therefore, CT-P59 may be a promising therapeutic candidate for COVID-19.
Subject(s)
Antibodies, Neutralizing/pharmacology , COVID-19 Drug Treatment , Protein Binding/drug effects , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/drug effects , Angiotensin-Converting Enzyme 2/chemistry , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Chlorocebus aethiops , Disease Models, Animal , Female , Ferrets , Humans , Leukocytes, Mononuclear , Macaca mulatta , Male , Mesocricetus , Models, Molecular , Protein Conformation , Spike Glycoprotein, Coronavirus/chemistry , Vero CellsABSTRACT
Recent advances in soft materials and mechanics activate development of many new types of electrical medical implants. Electronic implants that provide exceptional functions, however, usually require more electrical power, resulting in shorter period of usages although many approaches have been suggested to harvest electrical power in human bodies by resolving the issues related to power density, biocompatibility, tissue damage, and others. Here, we report an active photonic power transfer approach at the level of a full system to secure sustainable electrical power in human bodies. The active photonic power transfer system consists of a pair of the skin-attachable photon source patch and the photovoltaic device array integrated in a flexible medical implant. The skin-attachable patch actively emits photons that can penetrate through live tissues to be captured by the photovoltaic devices in a medical implant. The wireless power transfer system is very simple, e.g., active power transfer in direct current (DC) to DC without extra circuits, and can be used for implantable medical electronics regardless of weather, covering by clothes, in indoor or outdoor at day and night. We demonstrate feasibility of the approach by presenting thermal and mechanical compatibility with soft live tissues while generating enough electrical power in live bodies through in vivo animal experiments. We expect that the results enable long-term use of currently available implants in addition to accelerating emerging types of electrical implants that require higher power to provide diverse convenient diagnostic and therapeutic functions in human bodies.
Subject(s)
Heart-Assist Devices , Photons , Wearable Electronic Devices , Wireless Technology/instrumentation , Animals , Heart Rate , Mice , Skin Physiological Phenomena , TransducersABSTRACT
Canine atopic dermatitis (CAD) is a ubiquitous, chronic inflammatory skin disorder prevalent in dogs, which results in production of abnormal levels of IgE antibodies in reciprocation to an allergen challenge. In this study, administration of the probiotic strain Lactobacillus sakei probio-65 for 2 months significantly reduced the disease severity index in experimental dogs diagnosed with CAD. In addition, one month pre-medication of L. sakei probio-65 revealed significant difference in the PVAS score in experimental dogs for both probio-65 and placebo groups. However, post 2 months treatment resulted in a significant decrease in the CASESI score values in the probio-65-treated group (p < .0.06).
Subject(s)
Dermatitis, Atopic/veterinary , Dog Diseases/prevention & control , Lactobacillus/growth & development , Probiotics/administration & dosage , Animals , Dermatitis, Atopic/pathology , Dermatitis, Atopic/prevention & control , Dog Diseases/pathology , Dogs , Double-Blind Method , Placebos/administration & dosage , Severity of Illness Index , Treatment OutcomeABSTRACT
An 8-month-old cat was presented with bilateral hydronephrosis. Bilateral ureteral obstructions were identified by diagnostic imaging and confirmed by necropsy. Histopathologic findings revealed polypoid transitional epithelial hyperplasia with chronic lymphoplasmacytic inflammation. This report documents congenital ureteral strictures as a cause of ureteral obstruction in a young cat.
Constriction urétérale bilatérale congénitale chez un jeune chat. Un chat âgé de 8 mois a été présenté avec une hydrophénose bilatérale. Des obstructions urétérales bilatérales ont été identifiées par imagerie diagnostique et confirmée par nécropsie. Les résultats histopathologiques ont révélé une hyperplasie épithéliale polypoïde transitionnelle avec une inflammation lymphoplasmacytique chronique. Ce rapport documente les constrictions urétérales congénitales comme cause de l'obstruction urétérale chez un jeune chat.(Traduit par Isabelle Vallières).
Subject(s)
Cat Diseases/diagnosis , Hydronephrosis/veterinary , Ureteral Obstruction/veterinary , Animals , Cat Diseases/diagnostic imaging , Cat Diseases/pathology , Cats , Constriction, Pathologic/veterinary , Diagnosis, Differential , Hydronephrosis/diagnosis , Male , Ultrasonography , Ureteral Obstruction/congenital , Ureteral Obstruction/diagnosisABSTRACT
PURPOSE: The study was done to construct and test a structural model to explain primipara breastfeeding behavior. METHODS: The participants were 213 primiparas on postpartum wards. Data were analyzed using the PASW 18.0 and AMOS 19.0 programs. RESULTS: Fitness statistics for the hypothetical model were appropriate (χ² =38.50, p=.070, GFI=.96, RMSEA=.05, AGFI=.93, NFI=.95, TLI=.97, CFI=.98, PNFI=.57, χ²/df=1.43). Breastfeeding behaviors were directly influenced by intention to breastfeed, perceived effectiveness of breastfeeding, and the amount of supplementary feeding. The amount of supplementary feeding had the largest direct impact on breastfeeding behavior. The largest total effect on breastfeeding behavior was intention to breastfeed. The environment of the maternity hospital indirectly influenced breastfeeding behavior. These factors explained 18.9% of variance in the primipara breastfeeding behavior. CONCLUSION: The results of the study indicate that in order to promote primipara breastfeeding the amount of supplementary feeding immediately after the birth should be limited and an environment that encourages exclusive breastfeeding in the hospital should be provided. The results also suggest it is necessary to provide nursing interventions that increase the intention to breastfeed and the perceived effectiveness of breastfeeding.
Subject(s)
Breast Feeding/statistics & numerical data , Models, Structural , Adult , Bottle Feeding , Female , Humans , Infant, Newborn , Intention , Mothers/psychology , Surveys and Questionnaires , Young AdultABSTRACT
Ovarian cancer is the most lethal gynecologic malignancy in women. Despite the fact that the metastatic spread is associated with the majority of deaths from ovarian cancer, the molecular mechanisms regulating the invasive and metastatic phenotypes of ovarian cancer are poorly understood. In this study, we demonstrated that BLT2, a low affinity leukotriene B(4) receptor, is highly expressed in OVCAR-3 and SKOV-3 human ovarian cancer cells, and that this receptor plays a key role in the invasiveness and metastasis of these cells through activation of STAT3 and consequent up-regulation of matrix metalloproteinase 2 (MMP2). In addition, our results suggest that activation of NAD(P)H oxidase-4 (NOX4) and subsequent reactive oxygen species (ROS) generation lie downstream of BLT2, mediating the stimulation of STAT3-MMP2 cascade in this process. For example, knockdown of BLT2 or NOX4 using each specific siRNA suppressed STAT3 stimulation and MMP2 expression. Similarly, inhibition of STAT3 suppressed the expression of MMP2, thus leading to attenuated invasiveness of these ovarian cancer cells. Finally, the metastasis of SKOV-3 cells in nude mice was markedly suppressed by pharmacological inhibition of BLT2. Together, our results implicate a BLT2-NOX4-ROS-STAT3-MMP2 cascade in the invasiveness and metastasis of ovarian cancer cells.
Subject(s)
Gene Expression Regulation, Neoplastic , Matrix Metalloproteinase 2/metabolism , Ovarian Neoplasms/metabolism , Receptors, Leukotriene B4/metabolism , STAT3 Transcription Factor/metabolism , 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid/pharmacology , Animals , Female , Humans , Mice , Mice, Inbred BALB C , Neoplasm Invasiveness , Neoplasm Metastasis , Ovarian Neoplasms/pathology , Phenotype , RNA Interference , Reactive Oxygen Species , Up-RegulationABSTRACT
PURPOSE: The purpose of this study was to identify attitudes of adolescents toward suicide. METHODS: Q-methodology which provides a method of analyzing the subjectivity of each item was used. Thirty middle and high school students classified 37 selected statements into a normal distribution using a 9 point scale. Collected data were analyzed using the Quanl PC Program. RESULTS: Three types of attitudes toward suicide were identified. The first type (opposing suicide-moral minded) showed an attitude of opposing suicide and thinking that suicide is a sin. The second type (understanding-empathizing suicidal person) showed an attitude of understanding the situation of the adolescents who has suicidal ideation and empathizing with them. The third type (ambivalent attitude) showed an attitude of understanding the suicidal person but, at the same time, opposing suicide. CONCLUSION: Results of the study indicate that different approaches to suicide prevention programs should be developed based on the three types of suicide attitudes among adolescents.
Subject(s)
Attitude to Death , Q-Sort , Suicide Prevention , Adolescent , Female , Humans , Interviews as Topic , Male , Mental Health , Suicide/psychology , Surveys and QuestionnairesABSTRACT
In mammalian cells, reactive oxygen species (ROS) are produced via a variety of cellular oxidative processes, including the activity of NADPH oxidases (NOX), the activity of xanthine oxidases, the metabolism of arachidonic acid (AA) by lipoxygenases (LOX) and cyclooxygenases (COX), and the mitochondrial respiratory chain. Although NOX-generated ROS are the best characterized examples of ROS in mammalian cells, ROS are also generated by the oxidative metabolism (e.g., via LOX and COX) of AA that is released from the membrane phospholipids via the activity of cytosolic phospholipase A(2) (cPLA(2)). Recently, growing evidence suggests that LOX- and COX-generated AA metabolites can induce ROS generation by stimulating NOX and that a potential signaling connection exits between the LOX/COX metabolites and NOX. In this review, we discuss the results of recent studies that report the generation of ROS by LOX metabolites, especially 5-LOX metabolites, via NOX stimulation. In particular, we have focused on the contribution of leukotriene B(4) (LTB(4)), a potent bioactive eicosanoid that is derived from 5-LOX, and its receptors, BLT1 and BLT2, to NOX stimulation through a signaling mechanism that leads to ROS generation.
Subject(s)
Arachidonate 5-Lipoxygenase , Arachidonic Acid/metabolism , Cytosol/metabolism , Leukotriene B4/metabolism , Mitochondria/metabolism , NADPH Oxidases , Reactive Oxygen Species/metabolism , Signal Transduction/physiology , Aging/metabolism , Animals , Apoptosis/physiology , Arachidonate 5-Lipoxygenase/metabolism , Cell Transformation, Neoplastic/metabolism , Humans , Mice , NADPH Oxidases/metabolism , Oxidation-Reduction , Phospholipases A/metabolism , Prostaglandin-Endoperoxide Synthases/metabolism , Xanthine Oxidase/metabolismABSTRACT
Mast cells are effector cells that mediate the allergic response through Ag stimulation of IgE bound to FcεRI. In allergic reactions, cross-linking of the surface receptors for IgE on mast cells results in the synthesis of Th2 cytokines such as IL-4 and IL-13, which are critical for the initiation and progression of the allergic response. Despite the important roles of these cytokines, the signaling mechanism by which Ag stimulation mediates the production of IL-4 and IL-13 in mast cells is not clearly understood. In the present study, we found that Ag-stimulated bone marrow-derived mast cells (BMMCs) highly upregulated the expression of BLT2, a leukotriene B(4) receptor, and that blockade of BLT2 with the specific antagonist LY255283 or small interfering RNA knockdown completely abolished the production of Th2 cytokines. Furthermore, BMMCs overexpressing BLT2 showed significantly enhanced production of Th2 cytokines compared with wild-type BMMCs. Additionally, we found that the generation of Nox1-derived reactive oxygen species occurs downstream of BLT2, thus mediating the synthesis of Th2 cytokines. Taken together, our results suggest that the BLT2-Nox1-reactive oxygen species cascade is a previously unsuspected mediatory signaling mechanism to Th2 cytokine production in Ag-stimulated BMMCs, thus contributing to allergic response.
Subject(s)
Cytokines/biosynthesis , Gene Expression Regulation/immunology , Mast Cells/metabolism , Receptors, Leukotriene B4/metabolism , Signal Transduction/immunology , Allergens/immunology , Animals , Antigen Presentation , Bone Marrow Cells/immunology , Bone Marrow Cells/metabolism , Cell Separation , Cytokines/immunology , Female , Flow Cytometry , Gene Expression , Hypersensitivity/immunology , Hypersensitivity/metabolism , Interleukin-3/biosynthesis , Interleukin-3/immunology , Interleukin-4/biosynthesis , Interleukin-4/immunology , Mast Cells/immunology , Mice , Mice, Inbred BALB C , Mice, Transgenic , NADH, NADPH Oxidoreductases/immunology , NADH, NADPH Oxidoreductases/metabolism , NADPH Oxidase 1 , RNA Interference , Reactive Oxygen Species , Receptors, Leukotriene B4/immunology , Reverse Transcriptase Polymerase Chain Reaction , Up-RegulationABSTRACT
Aggressive bladder cancer is a major cause of morbidity and mortality. Despite the fact that metastatic disease results in death in the majority of bladder cancer cases, the molecular events regulating the invasive phenotype of aggressive bladder cancer are not well understood. In this study, immunohistochemical examination showed that the leukotriene B(4) receptor BLT2 is overexpressed in advanced malignant bladder cancers (human transitional cell carcinomas) in proportion to advancing stages, with high prognostic significance (p<0.001). Blockade of BLT2 with the specific antagonist LY255283 or siRNA knockdown significantly suppressed the invasiveness of highly aggressive 253J-BV bladder cancer cells. Moreover, our results demonstrated that BLT2 mediates invasiveness through a signaling pathway dependent on NAD(P)H oxidase (Nox) 1- and Nox4-induced generation of reactive oxygen species (ROS) and subsequent NF-kappaB stimulation. Metastasis of 253J-BV cells in mice was also dramatically suppressed by inhibition of BLT2 or its signaling. These findings suggest that a BLT2-Nox-ROS-NF-kappaB cascade plays a critical role in bladder cancer invasion and metastasis.
Subject(s)
Carcinoma/metabolism , Lung Neoplasms/metabolism , NADPH Oxidases/metabolism , Reactive Oxygen Species/metabolism , Receptors, Leukotriene B4/metabolism , Urinary Bladder Neoplasms/metabolism , Animals , Carcinoma/diagnosis , Carcinoma/genetics , Carcinoma/physiopathology , Carcinoma/secondary , Cell Line, Tumor , Humans , Leukotriene B4/antagonists & inhibitors , Lung Neoplasms/diagnosis , Lung Neoplasms/genetics , Lung Neoplasms/physiopathology , Lung Neoplasms/secondary , Mice , Mice, Nude , NADPH Oxidase 1 , NADPH Oxidase 4 , NADPH Oxidases/genetics , NF-kappa B/genetics , NF-kappa B/metabolism , Neoplasm Invasiveness , Neoplasm Staging , Neoplasm Transplantation , Prognosis , RNA, Small Interfering/genetics , Receptors, Leukotriene B4/genetics , Signal Transduction/drug effects , Tetrazoles/pharmacology , Transcriptional Activation , Urinary Bladder Neoplasms/diagnosis , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/pathology , Urinary Bladder Neoplasms/physiopathologyABSTRACT
BLT2 is a low-affinity receptor for leukotriene B(4) (LTB(4)), a potent lipid mediator of inflammation generated from arachidonic acid via the 5-lipoxygenase pathway. Unlike BLT1, a high-affinity receptor for LTB(4), no clear physiological function has yet been identified for BLT2, especially with regard to the pathogenesis of asthma. The aim of this study was to investigate whether BLT2 plays a role in the pathogenesis of asthma. A murine model of allergic asthma was used to evaluate the role of BLT2 in ovalbumin-induced airway inflammation and airway hyperresponsiveness. The levels of BLT2 mRNA and its ligand, LTB(4), in the lung airway were highly elevated after ovalbumin challenge, and down-regulation of BLT2 with antisense BLT2 oligonucleotides markedly attenuated airway inflammation and airway hyperresponsiveness. Further analysis, aimed at identifying mediators downstream of BLT2, revealed that BLT2 activation led to elevation of reactive oxygen species and subsequent activation of NF-kappaB, thus inducing the expression of vascular cell adhesion molecule-1, which is known to be involved in eosinophil infiltration into the lung airway. Together, our results suggest that BLT2 plays a pivotal, mediatory role in the pathogenesis of asthma, acting through a "reactive oxygen species-NF-kappaB"-linked inflammatory signaling pathway.
Subject(s)
Bronchial Hyperreactivity/complications , Pneumonia/complications , Receptors, Leukotriene B4/antagonists & inhibitors , Receptors, Leukotriene B4/metabolism , Animals , Asthma/genetics , Asthma/physiopathology , Biopsy , Bronchi/drug effects , Bronchi/pathology , Bronchial Hyperreactivity/pathology , Bronchial Hyperreactivity/physiopathology , Cell Movement/drug effects , Gene Expression Regulation/drug effects , Humans , Lung/drug effects , Lung/pathology , Lung/physiopathology , Mice , NF-kappa B/metabolism , Ovalbumin , Pneumonia/pathology , Pneumonia/physiopathology , RNA, Antisense/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Reactive Oxygen Species/metabolism , Receptors, Leukotriene B4/genetics , Signal Transduction/drug effects , T-Lymphocytes/cytology , T-Lymphocytes/drug effects , Tetrazoles/pharmacology , Vascular Cell Adhesion Molecule-1/metabolismABSTRACT
Leukotriene B4 (LTB4) is an inflammatory mediator with potent biological activities in the pathogenesis of many inflammatory diseases. In the present study, we found that expression of BLT2, a low-affinity LTB4 receptor, is significantly upregulated in breast cancer cells. In addition, we observed that inhibition of BLT2 by a specific antagonist, LY255283, or by siBLT2 RNA interference caused dramatic apoptotic cell death in breast cancer cells, especially in the estrogen receptor (ER)-negative MDA-MB-468 and MDA-MB-453 cells, suggesting a role for BLT2 in survival of these breast cancer cells. In an approach to understand the downstream mechanism by which BLT2 mediates the potential pro-survival signaling, we found that the elevated reactive oxygen species (ROS) generation is associated with BLT2-mediated survival. Expression of Nox1, a member of the NADPH oxidase family, is also highly upregulated in a BLT2-dependent manner in these breast cancer cells, suggesting that 'Nox1-derived ROS' lie downstream of BLT2. Consistent with the proposed role of 'Nox1-ROS' in pro-survival signaling, knockdown of Nox1 with siNox1 or treatment with a ROS scavenging agent caused dramatic apoptotic death in these breast cancer cells. Taken together, our results demonstrate, for the first time, that the 'BLT2-Nox1-ROS'-linked cascade is involved in the pro-survival signaling, especially in ER-negative breast cancer cells.
Subject(s)
Breast Neoplasms/mortality , Reactive Oxygen Species/metabolism , Receptors, Estrogen/analysis , Receptors, Leukotriene B4/physiology , Signal Transduction/physiology , Breast Neoplasms/chemistry , Breast Neoplasms/metabolism , Cells, Cultured , Female , Humans , Leukotriene B4/physiology , NADPH Oxidase 1 , NADPH Oxidases/physiology , Receptors, Leukotriene B4/analysis , Tetrazoles/pharmacologyABSTRACT
OBJECTIVE: The leukotriene B(4) (LTB(4)) receptor BLT2 is expressed in endothelium, but no clear physiological function for it has yet been identified, especially in vascular angiogenesis. The purpose of this study is to characterize the potential function of BLT2 in vascular endothelial growth factor (VEGF)-induced angiogenesis. METHODS AND RESULTS: VEGF significantly upregulates BLT2 expression in human umbilical vein endothelial cells (HUVECs), and BLT2 knockdown by siRNA or inhibition of BLT2 by a specific BLT2 antagonist LY255283 attenuates VEGF-induced angiogenesis, which was determined by its effect on the formation of tube-like structures and on transmigration. The role of BLT2 in VEGF-induced angiogenesis was more evident in vivo, where BLT2 inhibition by LY255283 almost completely blocked VEGF-induced vessel formation in Matrigel-plug assays. In addition, we found that VEGF upregulates synthesis of the BLT2 ligand, 12(S)-hydroxyeicosatetraenoic acid (HETE). siRNA knockdown of 12-lipoxygenase (12-LO) expression attenuates VEGF-induced angiogenesis in HUVECs, and the addition of 12(S)-HETE to the 12-LO knockdown-HUVECs restores VEGF-induced angiogenesis. The activation of BLT2 itself by either 12(S)-HETE or LTB(4) evoked significant angiogenic phenotypes, both in vitro and in vivo. CONCLUSIONS: Our findings indicate that BLT2 plays an essential role in mediating VEGF-induced angiogenesis.
Subject(s)
Endothelial Cells/metabolism , Neovascularization, Physiologic , Receptors, Leukotriene B4/metabolism , Vascular Endothelial Growth Factor A/metabolism , 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid/metabolism , Animals , Arachidonate 12-Lipoxygenase/metabolism , Cell Movement , Cells, Cultured , Endothelial Cells/drug effects , Humans , Leukotriene Antagonists/pharmacology , Leukotriene B4/metabolism , Ligands , Mice , Mice, Transgenic , Neovascularization, Physiologic/drug effects , RNA Interference , RNA, Messenger/metabolism , RNA, Small Interfering/metabolism , Receptors, Leukotriene B4/antagonists & inhibitors , Receptors, Leukotriene B4/genetics , Tetrazoles/pharmacology , Up-RegulationABSTRACT
Indoledione derivatives have pronounced biological effects, i.e., cytotoxic activities against cancer cell lines and antifungal and antibacterial activities. The present study was designed to investigate the effects of YSK2821, a newly synthesized indoledione derivative, on platelet-derived growth factor (PDGF-BB)-induced vascular smooth muscle cell (VSMC) proliferation, as well as the molecular mechanisms of the anti-proliferative effects of YSK2821 in VSMCs. We found that YSK2821 caused the accumulation of cells in the G1 phase of the cell cycle and inhibited [3H]-thymidine incorporation. We demonstrated that YSK2821 remarkably decreased Akt kinase phosphorylation as the mechanism by which YSK2821 suppressed cell signal transduction events in VSMC proliferation. Furthermore, in terms of the effects of YSK2821 on cell cycle-related proteins, YSK2821 enhanced the expression of the cyclin-dependent protein kinase (CDK) inhibitor p27 and down-regulated CDK2 and cyclin E expression, but did not affect CDK4 and cyclin D1 expression. YSK2821 also inhibited the phosphorylation of Rb, a key regulator in the cell cycle. These results indicate that YSK2821, a newly synthesized indoledione derivative, may inhibit VSMC proliferation via a phosphatidylinositol (PI)-3 kinase-dependent pathway, and thus shed light on a novel role for YSK2821 as a potential preventive regulator of cardiovascular disease.