RESUMO
AIMS: Resistance to targeted therapy is one of the critical obstacles in cancer management. Resistance to trastuzumab frequently develops in the treatment for HER2+ cancers. The role of protein tyrosine phosphatases (PTPs) in trastuzumab resistance is not well understood. In this study, we aim to identify pivotal PTPs affecting trastuzumab resistance and devise a novel counteracting strategy. METHODS: Four public datasets were used to screen PTP candidates in relation to trastuzumab responsiveness in HER2+ breast cancer. Tyrosine kinase (TK) arrays were used to identify kinases that linked to protein tyrosine phosphate receptor type O (PTPRO)-enhanced trastuzumab sensitivity. The efficacy of small activating RNA (saRNA) in trastuzumab-conjugated silica nanoparticles was tested for PTPRO upregulation and resistance mitigation in cell models, a transgenic mouse model, and human cancer cell line-derived xenograft models. RESULTS: PTPRO was identified as the key PTP which influences trastuzumab responsiveness and patient survival. PTPRO de-phosphorated several TKs, including the previously overlooked substrate ERBB3, thereby inhibiting multiple oncogenic pathways associated with drug resistance. Notably, PTPRO, previously deemed "undruggable," was effectively upregulated by saRNA-loaded nanoparticles. The upregulated PTPRO simultaneously inhibited ERBB3, ERBB2, and downstream SRC signaling pathways, thereby counteracting trastuzumab resistance. CONCLUSIONS: Antibody-conjugated saRNA represents an innovative approach for targeting "undruggable" PTPs.
Assuntos
Neoplasias da Mama , Resistencia a Medicamentos Antineoplásicos , Nanopartículas , Receptor ErbB-2 , Trastuzumab , Ensaios Antitumorais Modelo de Xenoenxerto , Trastuzumab/farmacologia , Humanos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Animais , Camundongos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Feminino , Receptor ErbB-2/metabolismo , Receptor ErbB-2/antagonistas & inibidores , Linhagem Celular Tumoral , Nanopartículas/química , Camundongos Transgênicos , Antineoplásicos Imunológicos/farmacologia , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Transdução de Sinais/efeitos dos fármacosRESUMO
AIMS: Receptor-type vascular endothelial protein tyrosine phosphatase (VE-PTP) dephosphorylates Tie-2 as well as CD31, VE-cadherin, and vascular endothelial growth factor receptor 2 (VEGFR2). The latter form a signal transduction complex that mediates the endothelial cell response to shear stress, including the activation of the endothelial nitric oxide (NO) synthase (eNOS). As VE-PTP expression is increased in diabetes, we investigated the consequences of VE-PTP inhibition (using AKB-9778) on blood pressure in diabetic patients and the role of VE-PTP in the regulation of eNOS activity and vascular reactivity. METHODS AND RESULTS: In diabetic patients AKB-9778 significantly lowered systolic and diastolic blood pressure. This could be linked to elevated NO production, as AKB increased NO generation by cultured endothelial cells and elicited the NOS inhibitor-sensitive relaxation of endothelium-intact rings of mouse aorta. At the molecular level, VE-PTP inhibition increased the phosphorylation of eNOS on Tyr81 and Ser1177 (human sequence). The PIEZO1 activator Yoda1, which was used to mimic the response to shear stress, also increased eNOS Tyr81 phosphorylation, an effect that was enhanced by VE-PTP inhibition. Two kinases, i.e. abelson-tyrosine protein kinase (ABL)1 and Src were identified as eNOS Tyr81 kinases as their inhibition and down-regulation significantly reduced the basal and Yoda1-induced tyrosine phosphorylation and activity of eNOS. VE-PTP, on the other hand, formed a complex with eNOS in endothelial cells and directly dephosphorylated eNOS Tyr81 in vitro. Finally, phosphorylation of eNOS on Tyr80 (murine sequence) was found to be reduced in diabetic mice and diabetes-induced endothelial dysfunction (isolated aortic rings) was blunted by VE-PTP inhibition. CONCLUSIONS: VE-PTP inhibition enhances eNOS activity to improve endothelial function and decrease blood pressure indirectly, through the activation of Tie-2 and the CD31/VE-cadherin/VEGFR2 complex, and directly by dephosphorylating eNOS Tyr81. VE-PTP inhibition, therefore, represents an attractive novel therapeutic option for diabetes-induced endothelial dysfunction and hypertension.
Assuntos
Compostos de Anilina/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Diabetes Mellitus/tratamento farmacológico , Células Endoteliais/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Inibidores Enzimáticos/uso terapêutico , Hipertensão/tratamento farmacológico , Óxido Nítrico Sintase Tipo III/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Ácidos Sulfônicos/uso terapêutico , Animais , Pressão Sanguínea/efeitos dos fármacos , Células Cultivadas , Diabetes Mellitus/enzimologia , Diabetes Mellitus/genética , Diabetes Mellitus/fisiopatologia , Modelos Animais de Doenças , Células Endoteliais/enzimologia , Endotélio Vascular/enzimologia , Endotélio Vascular/fisiopatologia , Humanos , Hipertensão/enzimologia , Hipertensão/genética , Hipertensão/fisiopatologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/genética , Fosforilação , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Transdução de Sinais , Resultado do Tratamento , Estados UnidosRESUMO
Purpose: Tyrosine kinase with immunoglobulin-like and EGF-like domains 2 (Tie2) activation in Schlemm's canal (SC) endothelium is required for the maintenance of IOP, making the angiopoietin/Tie2 pathway a target for new and potentially disease modifying glaucoma therapies. The goal of the present study was to examine the effects of a Tie2 activator, AKB-9778, on IOP and outflow function. Methods: AKB-9778 effects on IOP was evaluated in humans, rabbits, and mice. Localization studies of vascular endothelial protein tyrosine phosphatase (VE-PTP), the target of AKB-9778 and a negative regulator of Tie2, were performed in human and mouse eyes. Mechanistic studies were carried out in mice, monitoring AKB-9778 effects on outflow facility, Tie2 phosphorylation, and filtration area of SC. Results: AKB-9778 lowered IOP in patients treated subcutaneously for diabetic eye disease. In addition to efficacious, dose-dependent IOP lowering in rabbit eyes, topical ocular AKB-9778 increased Tie2 activation in SC endothelium, reduced IOP, and increased outflow facility in mouse eyes. VE-PTP was localized to SC endothelial cells in human and mouse eyes. Mechanistically, AKB-9778 increased the filtration area of SC for aqueous humor efflux in both wild type and in Tie2+/- mice. Conclusions: This is the first report of IOP lowering in humans with a Tie2 activator and functional demonstration of its action in remodeling SC to increase outflow facility and lower IOP in fully developed mice. Based on these studies, a phase II clinical trial is in progress to advance topical ocular AKB-9778 as a first in class, Tie2 activator for treatment for ocular hypertension and glaucoma.
Assuntos
Compostos de Anilina/farmacologia , Pressão Intraocular/efeitos dos fármacos , Receptor TIE-2/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Ácidos Sulfônicos/farmacologia , Malha Trabecular/efeitos dos fármacos , Animais , Retinopatia Diabética/tratamento farmacológico , Método Duplo-Cego , Feminino , Imunofluorescência , Glaucoma/tratamento farmacológico , Glaucoma/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Malha Trabecular/metabolismo , Malha Trabecular/patologiaRESUMO
A series of novel triaryl-based sulfamic acid analogs was designed, synthesized and evaluated as inhibitors of human protein tyrosine phosphatase beta (HPTPß). A novel, easy and efficient synthetic method was developed for target compounds, and the activity determination results showed that most of compounds were good HPTPß inhibitors. Interestingly, the compounds G4 and G25 with simple structure not only showed potent inhibitory activity on HPTPß but also had good inhibitory selectivity over other PTPs (PTP1B, SHP2, LAR and TC-PTP). The molecular docking simulation of compounds with the protein HPTPß helped us understand the structure-activity relationship and clarify some confusing assay results. This research provides references for further drug design of HPTPß and other PTPs inhibitors.
Assuntos
Inibidores Enzimáticos/química , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Ácidos Sulfônicos/química , Derivados de Benzeno/química , Sítios de Ligação , Desenho de Fármacos , Inibidores Enzimáticos/metabolismo , Humanos , Simulação de Acoplamento Molecular , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Relação Estrutura-Atividade , Ácidos Sulfônicos/metabolismoRESUMO
Administration of interleukin (IL)-2 has led to a durable response in patients with advanced renal cancer and melanoma but is restricted for clinical application because of adverse effects, including the vascular leak syndrome (VLS). VLS is associated with increased circulating levels of the Tie2 antagonist ligand, angiopoietin 2, and decreased Tie2 receptor phosphorylation and downstream signaling in endothelial cells (ECs). Given that vascular endothelial protein tyrosine phosphatase (VE-PTP) is a specific membrane phosphatase in ECs that dephosphorylates Tie2, the effects of targeting VE-PTP by a selective inhibitor AKB-9778 (AKB) in terms of VLS and antitumor efficacy were examined in this study. The authors found, by targeting VE-PTP, that the antitumor effects induced by IL-2 were augmented [tumor-free 44% (IL-2 alone) vs. 87.5% (IL-2+AKB)], associated with enhanced immune cell infiltrate (90% increase for CD8 T cells and natural killer cells). In addition, the side effects of IL-2 therapy were lessened, as demonstrated by diminished lung weight (less vascular leakage) as well as reduced cytokine levels (serum HMGB1 from 137.04±2.69 to 43.86±3.65 pg/mL; interferon-γ from 590.52±90.52 to 31.37±1.14 pg/mL). The authors further sought to determine the potential mechanism of the action of AKB-9778. The findings suggest that AKB-9778 may function through reducing serum angiopoietin 2 level and regulating EC viability. These findings provide insights into the targeting VE-PTP to improve tolerance and efficacy of IL-2 therapy and highlight the clinical potential of AKB-9778 for treating patients with VLS and cancer.
Assuntos
Compostos de Anilina/farmacologia , Antineoplásicos/farmacologia , Interleucina-2/administração & dosagem , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Ácidos Sulfônicos/farmacologia , Compostos de Anilina/uso terapêutico , Animais , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Citocinas/sangue , Citocinas/metabolismo , Modelos Animais de Doenças , Sinergismo Farmacológico , Feminino , Expressão Gênica , Genes Reporter , Humanos , Mediadores da Inflamação , Interleucina-2/efeitos adversos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/secundário , Camundongos , Ácidos Sulfônicos/uso terapêutico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Inhibition of VE-PTP, an endothelial receptor-type tyrosine phosphatase, triggers phosphorylation of the tyrosine kinase receptor Tie-2, which leads to the suppression of inflammation-induced vascular permeability. Analyzing the underlying mechanism, we show here that inhibition of VE-PTP and activation of Tie-2 induce tyrosine phosphorylation of FGD5, a GTPase exchange factor (GEF) for Cdc42, and stimulate its translocation to cell contacts. Interfering with the expression of FGD5 blocks the junction-stabilizing effect of VE-PTP inhibition in vitro and in vivo. Likewise, FGD5 is required for strengthening cortical actin bundles and inhibiting radial stress fiber formation, which are each stimulated by VE-PTP inhibition. We identify Y820 of FGD5 as the direct substrate for VE-PTP. The phosphorylation of FGD5-Y820 is required for the stabilization of endothelial junctions and for the activation of Cdc42 by VE-PTP inhibition but is dispensable for the recruitment of FGD5 to endothelial cell contacts. Thus, activation of FGD5 is a two-step process that comprises membrane recruitment and phosphorylation of Y820. These steps are necessary for the junction-stabilizing effect stimulated by VE-PTP inhibition and Tie-2 activation.
Assuntos
Fatores de Troca do Nucleotídeo Guanina/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Junções Intercelulares/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Citoesqueleto de Actina/metabolismo , Motivos de Aminoácidos , Animais , Feminino , Fatores de Troca do Nucleotídeo Guanina/química , Fatores de Troca do Nucleotídeo Guanina/genética , Células HEK293 , Humanos , Camundongos , Mutação , Fosforilação , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismoRESUMO
Diabetic macular edema, also known as diabetic eye disease, is mainly caused by the overexpression of vascular endothelial protein tyrosine phosphatase (VE-PTP) at hypoxia/ischemic. AKB-9778 is a known VE-PTP inhibitor that can effectively interact with the active site of VE-PTP to inhibit the activity of VE-PTP. However, the binding pattern of VE-PTP with AKB-9778 and the dynamic implications of AKB-9778 on VE-PTP system at the molecular level are poorly understood. Through molecular docking, it was found that the AKB-9778 was docked well in the binding pocket of VE-PTP by the interactions of hydrogen bond and Van der Waals. Furthermore, after molecular dynamic simulations on VE-PTP system and VE-PTP AKB-9778 system, a series of postdynamic analyses found that the flexibility and conformation of the active site undergone an obvious transition after VE-PTP binding with AKB-9778. Moreover, by constructing the RIN, it was found that the different interactions in the active site were the detailed reasons for the conformational differences between these two systems. Thus, the finding here might provide a deeper understanding of AKB-9778 as VE-PTP Inhibitor.
Assuntos
Compostos de Anilina/química , Inibidores Enzimáticos/química , Hipoglicemiantes/química , Simulação de Acoplamento Molecular , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/química , Ácidos Sulfônicos/química , Motivos de Aminoácidos , Compostos de Anilina/metabolismo , Domínio Catalítico , Inibidores Enzimáticos/metabolismo , Humanos , Ligação de Hidrogênio , Hipoglicemiantes/metabolismo , Cinética , Simulação de Dinâmica Molecular , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Ácidos Sulfônicos/metabolismo , TermodinâmicaRESUMO
Dysregulation of protein tyrosine phosphatase, receptor type B (PTPRB) correlates with the development of a variety of tumors. Here we show that PTPRB promotes metastasis of colorectal cancer (CRC) cells via inducing epithelial-mesenchymal transition (EMT). We find that PTPRB is expressed at significantly higher levels in CRC tissues compared to adjacent nontumor tissues and in CRC cell lines with high invasion. PTPRB knockdown decreased the number of invasive CRC cells in an in vitro wound healing model, and also reduced tumor metastasis in vivo. Conversely, PTPRB overexpression promoted CRC cell invasion in vitro and metastasis in vivo. PTPRB overexpression decreased vimentin expression and promoted E-cadherin expression, consistent with promotion of EMT, while PTPRB knockdown had the opposite effect. Hypoxic conditions induced EMT and promoted invasion in CRC cells, but these effects were eliminated by PTPRB knockdown. EMT blockade via TWIST1 knockdown inhibited the migration and invasiveness of CRC cells, and even increased PTPRB expression could not reverse this effect. Altogether, these data support the conclusion that PTPRB promotes invasion and metastasis of CRC cells via inducing EMT, and that PTPRB would be a novel therapeutic target for the treatment of CRC.
Assuntos
Neoplasias Colorretais/patologia , Transição Epitelial-Mesenquimal , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Animais , Caderinas/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/metabolismo , Humanos , Masculino , Camundongos , Camundongos Nus , Invasividade Neoplásica , Metástase Neoplásica , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/uso terapêutico , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Transplante Heterólogo , Proteína 1 Relacionada a Twist/antagonistas & inibidores , Proteína 1 Relacionada a Twist/genética , Proteína 1 Relacionada a Twist/metabolismoRESUMO
Brown adipocytes have an important role in the regulation of energy balance through uncoupling protein-1 (UCP-1)-mediated nonshivering thermogenesis. Although brown adipocytes have been highlighted as a new therapeutic target for the treatment of metabolic diseases, such as obesity and type II diabetes in adult humans, the molecular mechanism underlying brown adipogenesis is not fully understood. We recently found that protein tyrosine phosphatase receptor type B (PTPRB) expression dramatically decreased during brown adipogenic differentiation. In this study, we investigated the functional roles of PTPRB and its regulatory mechanism during brown adipocyte differentiation. Ectopic expression of PTPRB led to a reduced brown adipocyte differentiation by suppressing the tyrosine phosphorylation of VEGFR2, whereas a catalytic inactive PTPRB mutant showed no effects on differentiation and phosphorylation. Consistently, the expression of brown adipocyte-related genes, such as UCP-1, PGC-1α, PRDM16, PPAR-γ, and CIDEA, were significantly inhibited by PTPRB overexpression. Overall, these results suggest that PTPRB functions as a negative regulator of brown adipocyte differentiation through its phosphatase activity-dependent mechanism and may be used as a target protein for the regulation of obesity and type II diabetes.
Assuntos
Adipócitos Marrons/efeitos dos fármacos , Adipogenia/fisiologia , Diferenciação Celular/efeitos dos fármacos , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Linhagem Celular , Diabetes Mellitus Tipo 2 , Regulação da Expressão Gênica , Humanos , NADH Desidrogenase , Obesidade , Fosforilação , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Tirosina/metabolismo , Proteína Desacopladora 1/metabolismoRESUMO
Inherited thrombocytopenias (ITs) are a heterogeneous group of disorders characterized by low platelet count that may result in bleeding tendency. Despite progress being made in defining the genetic causes of ITs, nearly 50% of patients with familial thrombocytopenia are affected with forms of unknown origin. Here, through exome sequencing of 2 siblings with autosomal-recessive thrombocytopenia, we identified biallelic loss-of-function variants in PTPRJ . This gene encodes for a receptor-like PTP, PTPRJ (or CD148), which is expressed abundantly in platelets and megakaryocytes. Consistent with the predicted effects of the variants, both probands have an almost complete loss of PTPRJ at the messenger RNA and protein levels. To investigate the pathogenic role of PTPRJ deficiency in hematopoiesis in vivo, we carried out CRISPR/Cas9-mediated ablation of ptprja (the ortholog of human PTPRJ) in zebrafish, which induced a significantly decreased number of CD41+ thrombocytes in vivo. Moreover, megakaryocytes of our patients showed impaired maturation and profound defects in SDF1-driven migration and formation of proplatelets in vitro. Silencing of PTPRJ in a human megakaryocytic cell line reproduced the functional defects observed in patients' megakaryocytes. The disorder caused by PTPRJ mutations presented as a nonsyndromic thrombocytopenia characterized by spontaneous bleeding, small-sized platelets, and impaired platelet responses to the GPVI agonists collagen and convulxin. These platelet functional defects could be attributed to reduced activation of Src family kinases. Taken together, our data identify a new form of IT and highlight a hitherto unknown fundamental role for PTPRJ in platelet biogenesis.
Assuntos
Plaquetas/patologia , Predisposição Genética para Doença , Megacariócitos/patologia , Mutação , Trombocitopenia/patologia , Adolescente , Adulto , Animais , Plaquetas/metabolismo , Sistemas CRISPR-Cas , Criança , Feminino , Seguimentos , Hematopoese , Humanos , Masculino , Megacariócitos/metabolismo , Pessoa de Meia-Idade , Linhagem , Prognóstico , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Trombocitopenia/etiologia , Trombocitopenia/genética , Peixe-ZebraRESUMO
Accurate protein structure in the ligand-bound state is a prerequisite for successful structure-based virtual screening (SBVS). Therefore, applications of SBVS against targets for which only an apo structure is available may be severely limited. To address this constraint, we developed a computational strategy to explore the ligand-bound state of a target protein, by combined use of molecular dynamics simulation, MM/GBSA binding energy calculation, and fragment-centric topographical mapping. Our computational strategy is validated against low-molecular weight protein tyrosine phosphatase (LMW-PTP) and then successfully employed in the SBVS against protein tyrosine phosphatase receptor type O (PTPRO), a potential therapeutic target for various diseases. The most potent hit compound GP03 showed an IC50 value of 2.89 µM for PTPRO and possessed a certain degree of selectivity toward other protein phosphatases. Importantly, we also found that neglecting the ligand energy penalty upon binding partially accounts for the false positive SBVS hits. The preliminary structure-activity relationships of GP03 analogs are also reported.
Assuntos
Desenho Assistido por Computador , Desenho de Fármacos , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Humanos , Ligantes , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/química , TermodinâmicaRESUMO
A series of novel (3'-amino-[1,1'-biphenyl]-4-yl) sulfamic acid derivatives were designed as nonphosphonate-based phosphotyrosy (pTyr) mimetics, synthesized and screened for use as HPTPß inhibitors. Compounds C22 and C2 showed favorable HPTPß inhibitory activity and better selectivity for HPTPß than for PTP1B and SHP2. Docking results suggested that compounds C2 and C22 could not only efficiently fit into the catalytic site of the HPTPß enzyme but also interact with the Lys1807, Arg1809 and Lys1811 residues of the secondary binding site, which was next to the catalytic center of the enzyme. The mode of interaction of the synthesized compound with the protein was different from the one found in a complex crystal of small molecules with HPTPß (2I4H), in which the inhibitory molecule formed hydrogen bonds with the Gln1948 and Asn1735 residues of the secondary binding site.
Assuntos
Compostos de Bifenilo/química , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Ácidos Sulfônicos/química , Compostos de Bifenilo/síntese química , Domínio Catalítico , Desenho de Fármacos , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/química , Relação Estrutura-Atividade , Ácidos Sulfônicos/síntese químicaRESUMO
Protein tyrosine phosphatases (PTPs), of the receptor and non-receptor classes, are key signaling molecules that play critical roles in cellular regulation underlying diverse physiological events. Aberrant signaling as a result of genetic mutation or altered expression levels has been associated with several diseases and treatment via pharmacological intervention at the level of PTPs has been widely explored; however, the challenges associated with development of small molecule phosphatase inhibitors targeting the intracellular phosphatase domain (the "inside-out" approach) have been well documented and as yet there are no clinically approved drugs targeting these enzymes. The alternative approach of targeting receptor PTPs with biotherapeutic agents (such as monoclonal antibodies or engineered fusion proteins; the "outside-in" approach) that interact with the extracellular ectodomain offers many advantages, and there have been a number of exciting recent developments in this field. Here we provide a brief overview of the receptor PTP family and an update on the emerging area of receptor PTP-targeted biotherapeutics for CD148, vascular endothelial-protein tyrosine phosphatase (VE-PTP), receptor-type PTPs σ, γ, ζ (RPTPσ, RPTPγ, RPTPζ) and CD45, and discussion of future potential in this area.
Assuntos
Anticorpos Neutralizantes/farmacologia , Inibidores Enzimáticos/farmacologia , Imunoconjugados/farmacologia , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteínas Tirosina Fosfatases Semelhantes a Receptores/antagonistas & inibidores , Animais , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/enzimologia , Artrite Reumatoide/genética , Artrite Reumatoide/patologia , Asma/tratamento farmacológico , Asma/enzimologia , Asma/genética , Asma/patologia , Inibidores Enzimáticos/síntese química , Regulação da Expressão Gênica , Humanos , Imunoconjugados/química , Imunotoxinas/química , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Neoplasias/genética , Neoplasias/patologia , Domínios Proteicos , Proteínas Tirosina Fosfatases Semelhantes a Receptores/química , Proteínas Tirosina Fosfatases Semelhantes a Receptores/genética , Proteínas Tirosina Fosfatases Semelhantes a Receptores/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/química , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Proteínas Inativadoras de Ribossomos Tipo 1/química , Saporinas , Transdução de SinaisRESUMO
Two new meroterpenoid-type fungal metabolites, furanoaustinol (1) and 7-acetoxydehydroaustinol (2), were isolated from the ethyl acetate extract of a marine-derived fungal strain Penicillium sp. SF-5497, along with eight (3-10) known meroterpenoids. Their structures were elucidated mainly based on the analysis of their NMR (1D and 2D) and MS data. Particularly, the novel meroterpenoid, furanoaustinol (1), belonging to the austin group, was identified to possess an unprecedented hexacyclic ring system. Biological evaluation of these compounds revealed that furanoaustinol (1) weakly inhibited the activity of protein tyrosine phosphatase 1B in a dose-dependent manner with an IC50 value of 77.2 µM. In addition, 7-acetoxydehydroaustinol (2) and four other known meroterpenoids (5, 7, 9, and 10) weakly suppressed the overproduction of nitric oxide in lipopolysaccharide-challenged BV2 microglial cells with IC50 values of 61.0, 30.1, 58.3, 37.6, and 40.2 µM, respectively.
Assuntos
Penicillium/química , Terpenos/isolamento & purificação , Relação Dose-Resposta a Droga , Fermentação , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Microglia/efeitos dos fármacos , Microglia/metabolismo , Estrutura Molecular , Óxido Nítrico/biossíntese , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidoresRESUMO
PURPOSE: To assess the effect of AKB-9778 alone or in combination with ranibizumab in subjects with diabetic macular edema (DME). DESIGN: A phase IIa, randomized, placebo- and sham injection-controlled, double-masked clinical trial. PARTICIPANTS: Subjects (n = 144) with decreased vision from DME and central subfield thickness (CST) ≥325 µm measured by spectral-domain optical coherence tomography (SD OCT) enrolled at 36 sites. METHODS: Subjects were randomized to (1) AKB-9778 monotherapy: subcutaneous AKB-9778 15 mg twice per day (BID) + monthly sham intraocular injections; (2) combination therapy: subcutaneous AKB-9778 15 mg BID + monthly 0.3 mg ranibizumab; or (3) ranibizumab monotherapy: subcutaneous placebo injections BID + monthly 0.3 mg ranibizumab. Best-corrected visual acuity (BCVA) and CST were measured at baseline and every 4 weeks. MAIN OUTCOME MEASURES: Primary outcome measure was mean change from baseline CST at week 12. Other outcomes included BCVA, safety assessments, and Diabetic Retinopathy Severity Score (DRSS). RESULTS: At week 12, mean change from baseline CST was significantly greater in the combination group (-164.4±24.2 µm) compared with the ranibizumab monotherapy group (-110.4±17.2 µm; P = 0.008) and was 6.2±13.0 µm in the AKB-9778 monotherapy group. Mean CST at week 12 and percentage of eyes with resolved edema was 340.0±11.2 µm and 29.2%, respectively, in the combination group versus 392.1±17.1 µm and 17.0%, respectively, in the ranibizumab monotherapy group. Mean change from baseline BCVA (letters) was 6.3±1.3 in the combination group, 5.7±1.2 in the ranibizumab monotherapy group, and 1.5±1.2 in the AKB-9778 monotherapy group. The percentage of study eyes that gained ≥10 or ≥15 letters was 8.7% and 4.3%, respectively, in the AKB-9778 monotherapy group, 29.8% and 17.0%, respectively, in the ranibizumab monotherapy group, and 35.4% and 20.8%, respectively, in the combination group. Improvements in DRSS in study eyes were similar across groups, and the percentage of qualified fellow eyes with a ≥2-step change was 11.4% in all AKB-9778-treated subjects compared with 4.2% in the ranibizumab monotherapy group. AKB-9778 was well tolerated, with no clear by-treatment differences in adverse events. CONCLUSIONS: Activation of Tie2 by subcutaneous injections of AKB-9778 combined with suppression of vascular endothelial growth factor (VEGF) causes a significantly greater reduction in DME than that seen with suppression of VEGF alone.
Assuntos
Inibidores da Angiogênese/uso terapêutico , Compostos de Anilina/uso terapêutico , Retinopatia Diabética/tratamento farmacológico , Edema Macular/tratamento farmacológico , Ranibizumab/uso terapêutico , Receptor TIE-2/metabolismo , Ácidos Sulfônicos/uso terapêutico , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 2/complicações , Retinopatia Diabética/diagnóstico , Retinopatia Diabética/metabolismo , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Angiofluoresceinografia , Humanos , Injeções Subcutâneas , Injeções Intravítreas , Edema Macular/diagnóstico , Edema Macular/metabolismo , Masculino , Pessoa de Meia-Idade , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Tomografia de Coerência Óptica , Acuidade VisualRESUMO
Gene therapy is a promising therapeutic approach for chemoresistant cervical cancers. Therapeutic interventions targeting the key factors contributing to the initiation and progression of cervical cancer may be a more effective treatment strategy. In the present study, we firstly determined the expression of protein tyrosine phosphatase receptor J (PTPRJ) in 8-paired human cervical tumor and non-tumor tissues. We observed a striking downregulation of PTPRJ in the human cervical tumor tissues. Next, we investigated the roles and the function mechanism of PTPRJ in the human cervical carcinoma cell line C33A by loss- and gain-of-function experiments. Our study indicated that C33A cells with loss of PTPRJ expression showed a significantly increased cell viability, rising growth and migration rate, as well as a G1-S transition. We obtained the opposite results when we overexpressed PTPRJ in C33A cells. Our further study indicated that PTPRJ levels were highly correlated with cell survival when the C33A cells were treated with 5-fluorouracil (5-FU), an important chemotherapeutic agent for cervical cancer. In addition, the signaling pathway screening assay showed an obvious alteration of the Janus kinase 1/signal transducer and activator of transcription 3 (JAK1/STAT3) pathway. PTPRJ negatively regulated the activation of the JAK1/STAT3 pathway by decreasing the phosphorylation levels of JAK1 and STAT3. In addition, PTPRJ also regulated the expression of the downstream factors of STAT3, such as cyclin D, Bax, VEGF and MMP2. Our results suggest that PTPRJ may be a promising gene therapy target and its therapeutic potential can be fulfilled when used alone, or in combination with other anticancer agents.
Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Carcinoma/patologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Fluoruracila/farmacologia , Proteínas de Neoplasias/antagonistas & inibidores , Processamento de Proteína Pós-Traducional , Transdução de Sinais/fisiologia , Proteínas Supressoras de Tumor/fisiologia , Neoplasias do Colo do Útero/patologia , Carcinoma/enzimologia , Divisão Celular , Linhagem Celular Tumoral , Movimento Celular , Ativação Enzimática , Feminino , Pontos de Checagem da Fase G1 do Ciclo Celular , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Células HEK293 , Humanos , Janus Quinase 1 , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/fisiologia , Fosforilação , RNA Mensageiro/biossíntese , RNA Neoplásico/biossíntese , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/biossíntese , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/fisiologia , Proteínas Recombinantes de Fusão/metabolismo , Fator de Transcrição STAT3 , Proteínas Supressoras de Tumor/antagonistas & inibidores , Proteínas Supressoras de Tumor/biossíntese , Neoplasias do Colo do Útero/enzimologiaRESUMO
PURPOSE: AKB-9778 is a small-molecule competitive inhibitor of vascular endothelial-protein tyrosine phosphatase (VE-PTP) that promotes Tie2 activation and reduces vascular leakage and neovascularization in mouse models. The purpose of this study was to test the safety, tolerability, pharmacokinetics, and biological activity of AKB-9778 in patients with diabetic macular edema (DME). DESIGN: Open-label, dose-escalation clinical trial. PARTICIPANTS: Four dose cohorts of 6 patients with DME self-administered subcutaneous injections of 5 mg, 15 mg, 22.5 mg, or 30 mg AKB-9778 twice daily for 4 weeks. METHODS: Patients were seen weekly during a 4-week treatment period for safety assessments, best-corrected visual acuity (BCVA) assessment by Early Treatment Diabetic Retinopathy Study protocol, and measurement of central subfield thickness (CST) by spectral-domain optical coherence tomography. Additional safety assessments were performed at 6, 8, and 12 weeks. MAIN OUTCOME MEASURES: Safety assessments, change from baseline BCVA, and change from baseline CST. RESULTS: All doses were well tolerated. A modest, transient reduction in blood pressure and adverse events consistent with vasodilatory activity of AKB-9778 emerged at doses of 22.5 mg or more twice daily. At the week 4 primary end point, BCVA improved 5 letters or more from baseline in 13 of the 18 patients receiving 15 mg or more twice daily; 1 patient improved by 10 to 15 letters, and 2 patients improved by more than 15 letters. Among 18 patients receiving 15 mg or more twice daily, CST decreased by more than 100 µm in 5 patients and by 50 to 100 µm in 2 patients. There was a significant correlation between reduction in CST and improvement in BCVA. CONCLUSIONS: No safety concerns were identified after systemic administration of AKB-9778 for 4 weeks in patients with DME, and doses of 15 mg or more twice daily reduced macular edema and improved vision in some patients. This is a preliminary demonstration of clinical safety and efficacy of a VE-PTP inhibitor and Tie2 activator.
Assuntos
Compostos de Anilina/administração & dosagem , Retinopatia Diabética/tratamento farmacológico , Inibidores Enzimáticos/administração & dosagem , Edema Macular/tratamento farmacológico , Receptor TIE-2/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Ácidos Sulfônicos/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Compostos de Anilina/efeitos adversos , Pressão Sanguínea/efeitos dos fármacos , Retinopatia Diabética/metabolismo , Inibidores Enzimáticos/efeitos adversos , Feminino , Angiofluoresceinografia , Humanos , Injeções Subcutâneas , Edema Macular/metabolismo , Masculino , Pessoa de Meia-Idade , Ácidos Sulfônicos/efeitos adversos , Tomografia de Coerência Óptica , Acuidade Visual/fisiologiaRESUMO
Protein tyrosine phosphatase receptor type Q (PTPRQ) is an unusual PTP that has intrinsic dephosphorylating activity for various phosphatidyl inositides instead of phospho-tyrosine substrates. Although PTPRQ was known to be involved in the pathogenesis of obesity, no small-molecule inhibitor has been reported so far. Here we report six novel PTPRQ inhibitors identified with computer-aided drug design protocol involving the virtual screening with docking simulations and enzyme inhibition assay. These inhibitors exhibit moderate potencies against PTPRQ with the associated IC50 values ranging from 29 to 86 µM. Because the newly discovered inhibitors were also computationally screened for having desirable physicochemical properties as a drug candidate, they deserve consideration for further development by structure-activity relationship studies to optimize the antiobestic activities. Structural features relevant to the stabilization of the inhibitors in the active site of PTPRQ are addressed in detail.
Assuntos
Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/análise , Inibidores Enzimáticos/farmacologia , Simulação de Acoplamento Molecular , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Interface Usuário-Computador , Domínio Catalítico , Inibidores Enzimáticos/química , Humanos , Hidrólise/efeitos dos fármacos , Concentração Inibidora 50 , Fosfatos de Inositol/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/química , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismoAssuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/patologia , Inibidores Enzimáticos/farmacologia , Neoplasias Pulmonares/prevenção & controle , Neovascularização Patológica/tratamento farmacológico , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/antagonistas & inibidores , Proteínas de Peixe-Zebra/metabolismo , Animais , Feminino , Receptor TIE-2/metabolismoRESUMO
BACKGROUND: The solid tumor microvasculature is characterized by structural and functional abnormality and mediates several deleterious aspects of tumor behavior. Here we determine the role of vascular endothelial protein tyrosine phosphatase (VE-PTP), which deactivates endothelial cell (EC) Tie-2 receptor tyrosine kinase, thereby impairing maturation of tumor vessels. METHODS: AKB-9778 is a first-in-class VE-PTP inhibitor. We examined its effects on ECs in vitro and on embryonic angiogenesis in vivo using zebrafish assays. We studied the impact of AKB-9778 therapy on the tumor vasculature, tumor growth, and metastatic progression using orthotopic models of murine mammary carcinoma as well as spontaneous and experimental metastasis models. Finally, we used endothelial nitric oxide synthase (eNOS)-deficient mice to establish the role of eNOS in mediating the effects of VE-PTP inhibition. All statistical tests were two-sided. RESULTS: AKB-9778 induced ligand-independent Tie-2 activation in ECs and impaired embryonic zebrafish angiogenesis. AKB-9778 delayed the early phase of mammary tumor growth by maintaining vascular maturity (P < .01, t test); slowed growth of micrometastases (P < .01, χ(2) test) by preventing extravasation of tumor cells (P < 0.01, Fisher exact test), resulting in a trend toward prolonged survival (27.0 vs 36.5 days; hazard ratio of death = 0.33, 95% confidence interval = 0.11 to 1.03; P = .05, Mantel-Cox test); and stabilized established primary tumor blood vessels, enhancing tumor perfusion (P = .03 for 4T1 tumor model and 0.05 for E0771 tumor model, by two-sided t tests) and, hence, radiation response (P < .01, analysis of variance; n = 7 mice per group). The effects of AKB-9778 on tumor vessels were mediated in part by endothelial nitric oxide synthase activation. CONCLUSIONS: Our results demonstrate that pharmacological VE-PTP inhibition can normalize the structure and function of tumor vessels through Tie-2 activation, which delays tumor growth, slows metastatic progression, and enhances response to concomitant cytotoxic treatments.