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1.
Am J Physiol Cell Physiol ; 326(3): C880-C892, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38223924

RESUMO

17-ß-hydroxysteroid dehydrogenase 13 (HSD17B13), a lipid droplet-associated enzyme, is primarily expressed in the liver and plays an important role in lipid metabolism. Targeted inhibition of enzymatic function is a potential therapeutic strategy for treating steatotic liver disease (SLD). The present study is aimed at investigating the effects of the first selective HSD17B13 inhibitor, BI-3231, in a model of hepatocellular lipotoxicity using human cell lines and primary mouse hepatocytes in vitro. Lipotoxicity was induced with palmitic acid in HepG2 cells and freshly isolated mouse hepatocytes and the cells were coincubated with BI-3231 to assess the protective effects. Under lipotoxic stress, triglyceride (TG) accumulation was significantly decreased in the BI-3231-treated cells compared with that of the control untreated human and mouse hepatocytes. In addition, treatment with BI-3231 led to considerable improvement in hepatocyte proliferation, cell differentiation, and lipid homeostasis. Mechanistically, BI-3231 increased the mitochondrial respiratory function without affecting ß-oxidation. BI-3231 inhibited the lipotoxic effects of palmitic acid in hepatocytes, highlighting the potential of targeting HSD17B13 as a specific therapeutic approach in steatotic liver disease.NEW & NOTEWORTHY 17-ß-Hydroxysteroid dehydrogenase 13 (HSD17B13) is a lipid droplet protein primarily expressed in the liver hepatocytes. HSD17B13 is associated with the clinical outcome of chronic liver diseases and is therefore a target for the development of drugs. Here, we demonstrate the promising therapeutic effect of BI-3231 as a potent inhibitor of HSD17B13 based on its ability to inhibit triglyceride accumulation in lipid droplets (LDs), restore lipid metabolism and homeostasis, and increase mitochondrial activity in vitro.


Assuntos
Fígado Gorduroso , Ácido Palmítico , Humanos , Animais , Camundongos , Ácido Palmítico/toxicidade , Inibidores Enzimáticos/farmacologia , Hepatócitos , Triglicerídeos
2.
Hepatology ; 77(3): 802-815, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35976053

RESUMO

BACKGROUND AND AIMS: Current liver-directed gene therapies look for adeno-associated virus (AAV) vectors with improved efficacy. With this background, capsid engineering is explored. Whereas shuffled capsid library screenings have resulted in potent liver targeting variants with one first vector in human clinical trials, modifying natural serotypes by peptide insertion has so far been less successful. Here, we now report on two capsid variants, MLIV.K and MLIV.A, both derived from a high-throughput in vivo AAV peptide display selection screen in mice. APPROACH AND RESULTS: The variants transduce primary murine and human hepatocytes at comparable efficiencies, a valuable feature in clinical development, and show significantly improved liver transduction efficacy, thereby allowing a dose reduction, and outperform parental AAV2 and AAV8 in targeting human hepatocytes in humanized mice. The natural heparan sulfate proteoglycan binding ability is markedly reduced, a feature that correlates with improved hepatocyte transduction. A further property that might contribute to the improved transduction efficacy is the lower capsid melting temperature. Peptide insertion also caused a moderate change in sensitivity to human sera containing anti-AAV2 neutralizing antibodies, revealing the impact of epitopes located at the basis of the AAV capsid protrusions. CONCLUSIONS: In conclusion, MLIV.K and MLIV.A are AAV peptide display variants selected in immunocompetent mice with improved hepatocyte tropism and transduction efficiency. Because these features are maintained across species, MLIV variants provide remarkable potential for translation of therapeutic approaches from mice to men.


Assuntos
Capsídeo , Dependovirus , Animais , Camundongos , Humanos , Capsídeo/química , Capsídeo/metabolismo , Sorogrupo , Dependovirus/genética , Transdução Genética , Vetores Genéticos , Fígado/metabolismo , Peptídeos/análise , Peptídeos/genética , Peptídeos/metabolismo , Terapia Genética/métodos
3.
Am J Physiol Cell Physiol ; 325(1): C129-C140, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37273239

RESUMO

Liver cirrhosis is the end stage of all chronic liver diseases and contributes significantly to overall mortality of 2% globally. The age-standardized mortality from liver cirrhosis in Europe is between 10 and 20% and can be explained by not only the development of liver cancer but also the acute deterioration in the patient's overall condition. The development of complications including accumulation of fluid in the abdomen (ascites), bleeding in the gastrointestinal tract (variceal bleeding), bacterial infections, or a decrease in brain function (hepatic encephalopathy) define an acute decompensation that requires therapy and often leads to acute-on-chronic liver failure (ACLF) by different precipitating events. However, due to its complexity and organ-spanning nature, the pathogenesis of ACLF is poorly understood, and the common underlying mechanisms leading to the development of organ dysfunction or failure in ACLF are still elusive. Apart from general intensive care interventions, there are no specific therapy options for ACLF. Liver transplantation is often not possible in these patients due to contraindications and a lack of prioritization. In this review, we describe the framework of the ACLF-I project consortium funded by the Hessian Ministry of Higher Education, Research and the Arts (HMWK) based on existing findings and will provide answers to these open questions.


Assuntos
Insuficiência Hepática Crônica Agudizada , Doença Hepática Terminal , Varizes Esofágicas e Gástricas , Humanos , Doença Hepática Terminal/complicações , Varizes Esofágicas e Gástricas/complicações , Hemorragia Gastrointestinal/complicações , Cirrose Hepática/complicações , Cirrose Hepática/terapia , Insuficiência Hepática Crônica Agudizada/terapia , Insuficiência Hepática Crônica Agudizada/etiologia
4.
Int J Mol Sci ; 24(6)2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36982773

RESUMO

CEND-1 (iRGD) is a bifunctional cyclic peptide that can modulate the solid tumour microenvironment, enhancing the delivery and therapeutic index of co-administered anti-cancer agents. This study explored CEND-1's pharmacokinetic (PK) properties pre-clinically and clinically, and assessed CEND-1 distribution, tumour selectivity and duration of action in pre-clinical tumour models. Its PK properties were assessed after intravenous infusion of CEND-1 at various doses in animals (mice, rats, dogs and monkeys) and patients with metastatic pancreatic cancer. To assess tissue disposition, [3H]-CEND-1 radioligand was administered intravenously to mice bearing orthotopic 4T1 mammary carcinoma, followed by tissue measurement using quantitative whole-body autoradiography or quantitative radioactivity analysis. The duration of the tumour-penetrating effect of CEND-1 was evaluated by assessing tumour accumulation of Evans blue and gadolinium-based contrast agents in hepatocellular carcinoma (HCC) mouse models. The plasma half-life was approximately 25 min in mice and 2 h in patients following intravenous administration of CEND-1. [3H]-CEND-1 localised to the tumour and several healthy tissues shortly after administration but was cleared from most healthy tissues by 3 h. Despite the rapid systemic clearance, tumours retained significant [3H]-CEND-1 several hours post-administration. In mice with HCC, the tumour penetration activity remained elevated for at least 24 h after the injection of a single dose of CEND-1. These results indicate a favourable in vivo PK profile of CEND-1 and a specific and sustained tumour homing and tumour penetrability. Taken together, these data suggest that even single injections of CEND-1 may elicit long-lasting tumour PK improvements for co-administered anti-cancer agents.


Assuntos
Antineoplásicos , Carcinoma Hepatocelular , Neoplasias Hepáticas , Ratos , Camundongos , Animais , Cães , Infusões Intravenosas , Peptídeos , Microambiente Tumoral
5.
Int J Cancer ; 148(1): 226-237, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32700769

RESUMO

Hepatocellular carcinoma (HCC) is highly resistant to anticancer therapy and novel therapeutic strategies are needed. Chronotherapy may become a promising approach because it may improve the efficacy of antimitotic radiation and chemotherapy by considering timing of treatment. To date little is known about time-of-day dependent changes of proliferation and DNA damage in HCC. Using transgenic c-myc/transforming growth factor (TGFα) mice as HCC animal model, we immunohistochemically demonstrated Ki67 as marker for proliferation and γ-H2AX as marker for DNA damage in HCC and surrounding healthy liver (HL). Core clock genes (Per1, Per2, Cry1, Cry2, Bmal 1, Rev-erbα and Clock) were examined by qPCR. Data were obtained from samples collected ex vivo at four different time points and from organotypic slice cultures (OSC). Significant differences were found between HCC and HL. In HCC, the number of Ki67 immunoreactive cells showed two peaks (ex vivo: ZT06 middle of day and ZT18 middle of night; OSC: CT04 and CT16). In ex vivo samples, the number of γ-H2AX positive cells in HCC peaked at ZT18 (middle of the night), while in OSC their number remained high during subjective day and night. In both HCC and HL, clock gene expression showed a time-of-day dependent expression ex vivo but no changes in OSC. The expression of Per2 and Cry1 was significantly lower in HCC than in HL. Our data support the concept of chronotherapy of HCC. OSC may become useful to test novel cancer therapies.


Assuntos
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Neoplasias Experimentais/genética , Proteínas Circadianas Period/genética , Animais , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/terapia , Proliferação de Células/genética , Cloretos/administração & dosagem , Cloretos/toxicidade , Cronoterapia , Dano ao DNA , Regulação Neoplásica da Expressão Gênica , Humanos , Fígado/patologia , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/terapia , Camundongos , Camundongos Transgênicos , Neoplasias Experimentais/induzido quimicamente , Neoplasias Experimentais/terapia , Fotoperíodo , Proteínas Proto-Oncogênicas c-myc/genética , Fator de Crescimento Transformador alfa/genética , Células Tumorais Cultivadas , Compostos de Zinco/administração & dosagem , Compostos de Zinco/toxicidade
6.
Gut ; 69(9): 1677-1690, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-31992593

RESUMO

OBJECTIVE: TGF-ß2 (TGF-ß, transforming growth factor beta), the less-investigated sibling of TGF-ß1, is deregulated in rodent and human liver diseases. Former data from bile duct ligated and MDR2 knockout (KO) mouse models for human cholestatic liver disease suggested an involvement of TGF-ß2 in biliary-derived liver diseases. DESIGN: As we also found upregulated TGFB2 in liver tissue of patients with primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), we now fathomed the positive prospects of targeting TGF-ß2 in early stage biliary liver disease using the MDR2-KO mice. Specifically, the influence of TgfB2 silencing on the fibrotic and inflammatory niche was analysed on molecular, cellular and tissue levels. RESULTS: TgfB2-induced expression of fibrotic genes in cholangiocytes and hepatic stellate cellswas detected. TgfB2 expression in MDR2-KO mice was blunted using TgfB2-directed antisense oligonucleotides (AON). Upon AON treatment, reduced collagen deposition, hydroxyproline content and αSMA expression as well as induced PparG expression reflected a significant reduction of fibrogenesis without adverse effects on healthy livers. Expression analyses of fibrotic and inflammatory genes revealed AON-specific regulatory effects on Ccl3, Ccl4, Ccl5, Mki67 and Notch3 expression. Further, AON treatment of MDR2-KO mice increased tissue infiltration by F4/80-positive cells including eosinophils, whereas the number of CD45-positive inflammatory cells decreased. In line, TGFB2 and CD45 expression correlated positively in PSC/PBC patients and localised in similar areas of the diseased liver tissue. CONCLUSIONS: Taken together, our data suggest a new mechanistic explanation for amelioration of fibrogenesis by TGF-ß2 silencing and provide a direct rationale for TGF-ß2-directed drug development.


Assuntos
Colangite Esclerosante , Inativação Gênica , Cirrose Hepática Biliar , Cirrose Hepática , Oligonucleotídeos Antissenso , Fator de Crescimento Transformador beta2/genética , Fator de Crescimento Transformador beta2/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Animais , Colangite Esclerosante/metabolismo , Colangite Esclerosante/patologia , Modelos Animais de Doenças , Descoberta de Drogas , Regulação da Expressão Gênica , Células Estreladas do Fígado/metabolismo , Humanos , Cirrose Hepática/metabolismo , Cirrose Hepática/patologia , Cirrose Hepática/prevenção & controle , Cirrose Hepática Biliar/metabolismo , Cirrose Hepática Biliar/patologia , Camundongos , Camundongos Knockout , Regulação para Cima , Membro 4 da Subfamília B de Transportadores de Cassetes de Ligação de ATP
7.
Cell Physiol Biochem ; 45(6): 2516-2528, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29587249

RESUMO

BACKGROUND/AIMS: Signaling of Gs protein-coupled receptors (GsPCRs) is accomplished by stimulation of adenylyl cyclase, causing an increase of the intracellular cAMP concentration, activation of the intracellular cAMP effectors protein kinase A (PKA) and Epac, and an efflux of cAMP, the function of which is still unclear. METHODS: Activation of adenylyl cyclase by GsPCR agonists or cholera toxin was monitored by measurement of the intracellular cAMP concentration by ELISA, anti-phospho-PKA substrate motif phosphorylation by immunoblotting, and an Epac-FRET assay in the presence and absence of adenosine receptor antagonists or ecto-nucleotide phosphodiesterase/pyrophosphatase2 (eNPP2) inhibitors. The production of AMP from cAMP by recombinant eNPP2 was measured by HPLC. Extracellular adenosine was determined by LC-MS/MS, extracellular ATP by luciferase and LC-MS/MS. The expression of eNPP isoenzymes 1-3 was examined by RT-PCR. The expression of multidrug resistance protein 4 was suppressed by siRNA. RESULTS: Here we show that the activation of GsPCRs and the GsPCRs-independent activation of Gs proteins and adenylyl cyclase by cholera toxin induce stimulation of cell surface adenosine receptors (A2A or A2B adenosine receptors). In PC12 cells stimulation of adenylyl cyclase by GsPCR or cholera toxin caused activation of A2A adenosine receptors by an autocrine signaling pathway involving cAMP efflux through multidrug resistance protein 4 and hydrolysis of released cAMP to AMP by eNPP2. In contrast, in PC3 cells cholera toxin- and GsPCR-induced stimulation of adenylyl cyclase resulted in the activation of A2B adenosine receptors. CONCLUSION: Our findings show that stimulation of adenylyl cyclase causes a remarkable activation of cell surface adenosine receptors.


Assuntos
Adenilil Ciclases/metabolismo , Receptor A2A de Adenosina/metabolismo , Receptor A2B de Adenosina/metabolismo , Animais , AMP Cíclico/metabolismo , Ativação Enzimática , Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Células PC12 , Ratos , Transdução de Sinais
9.
Biochim Biophys Acta ; 1856(1): 130-43, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26142869

RESUMO

Radiation therapy is one of the most commonly used non-surgical interventions in tumor treatment and is often combined with other modalities to enhance its efficacy. Despite recent advances in radiation oncology, treatment responses, however, vary considerably between individual patients. A variety of approaches have been developed to enhance radiation response or to counteract resistance to ionizing radiation. Among them, a relatively novel class of radiation sensitizers comprises nanoparticles (NPs) which are highly efficient and selective systems in the nanometer range. NPs can either encapsulate radiation sensitizing agents, thereby protecting them from degradation, or sensitize cancer cells to ionizing radiation via their physicochemical properties, e.g. high Z number. Moreover, they can be chemically modified for active molecular targeting and the imaging of tumors. In this review we will focus on recent developments in nanotechnology, different classes and modifications of NPs and their radiation sensitizing properties.


Assuntos
Nanopartículas , Radioterapia , Antineoplásicos/uso terapêutico , Ensaios Clínicos como Assunto , Portadores de Fármacos , Humanos , Magnetismo , Fotoquimioterapia
10.
Liver Int ; 36(10): 1464-72, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-26991828

RESUMO

BACKGROUND & AIMS: Hepatocyte death is an important factor in development and progression of cirrhosis. Cytokeratin 18-based serum markers reflecting apoptotic (M30) and overall epithelial cell death (M65 and M65EpiDeath) have been used as prognostic parameters for survival in patients with acute liver failure. However, there has been no trial investigating M30, M65 and M65EpiDeath as survival parameters in patients with cirrhosis and acute-on-chronic liver failure. METHODS: Patients with cirrhosis were enrolled and followed until death, liver transplantation or last contact. M30, M65 and M65EpiDeath serum levels were quantified in patient's sera. RESULTS: Three hundred and thirty-one patients were screened and 211 patients could be included in this study. The median duration of follow-up was 322 days with a range of 1-1382 days. All three cell death parameters correlated with the extent of the severity of the disease. However, M65EpiDeath was the only of the three parameters which was associated with the severe complications of cirrhosis including ascites, spontaneous bacterial peritonitis and hepatorenal syndrome. Additionally, M65EpiDeath was the only cell death parameter which was independently from liver function and its surrogate parameter such as Child-Pugh score and the model of end-stage liver disease associated with overall survival. CONCLUSIONS: Epithelial cell death reflected by M65EpiDeath serum levels is an indicator for the severity of cirrhosis and a prognostic survival parameter in cirrhotic patients.


Assuntos
Morte Celular , Queratina-18/sangue , Cirrose Hepática/sangue , Cirrose Hepática/mortalidade , Fragmentos de Peptídeos/sangue , Adulto , Idoso , Ascite/etiologia , Biomarcadores/sangue , Progressão da Doença , Feminino , Alemanha , Síndrome Hepatorrenal/etiologia , Humanos , Cirrose Hepática/complicações , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Peritonite/etiologia , Peritonite/microbiologia , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos
11.
Exp Cell Res ; 330(1): 66-80, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25240929

RESUMO

The impact of the RNA-binding protein HuR for the post-transcriptional deregulation of tumor-relevant genes is well established. Despite of elevations in HuR expression levels, an increase in cytoplasmic HuR abundance in many cases correlates with a high grade of malignancy. Here, we demonstrated that administration of the actin-depolymerizing macrolide latrunculin A, or blebbistatin, an inhibitor of myosin II ATPase activity, caused a dose- and time-dependent reduction in the high cytoplasmic HuR content of HepG2 and Huh7 hepatocellular carcinoma (HCC) cells. Subcellular fractionation revealed that in addition, both inhibitors strongly attenuated cytoskeletal and membrane-bound HuR abundance and conversely increased the HuR amount in nuclear cell fractions. Concomitant with changes in intracellular HuR localization, both cytoskeletal inhibitors markedly decreased the half-lives of cyclooxygenase-2 (COX-2), cyclin A and cyclin D1 encoding mRNAs resulting in a significant reduction in their expression levels in HepG2 cells. Importantly, a similar reduction in the expression of these HuR targets was achieved by a RNA interference (RNAi)-mediated knockdown of either HuR or nonmuscle myoin IIA. Using polysomal fractionation, we further demonstrate that the decrease in cytoplasmic HuR by latrunculin A or blebbistatin is accompanied by a marked change in the allocation of HuR and its mRNA cargo from polysomes to ribonucleoprotein (RNP) particles. Functionally, the basal migration and prostaglandin E2 synthesis are similarly impaired in inhibitor-treated and stable HuR-knockdown HepG2 cells. Our data demonstrate that interfering with the actomyosin-dependent HuR trafficking may comprise a valid therapeutic option for antagonizing pathologic posttranscriptional gene expression by HuR and furthermore emphasize the potential benefit of HuR inhibitory strategies for treatment of HCC.


Assuntos
Antineoplásicos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Carcinoma Hepatocelular/metabolismo , Proteínas ELAV/metabolismo , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Neoplasias Hepáticas/metabolismo , Tiazolidinas/farmacologia , Ciclina A/genética , Ciclina A/metabolismo , Ciclina D/genética , Ciclina D/metabolismo , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Citoesqueleto/efeitos dos fármacos , Dinoprostona/metabolismo , Células Hep G2 , Humanos , Miosina não Muscular Tipo IIA/genética , Miosina não Muscular Tipo IIA/metabolismo , Polirribossomos/metabolismo , Transporte Proteico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ribonucleoproteínas/metabolismo
12.
Clin Sci (Lond) ; 128(1): 29-37, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24959956

RESUMO

Sorafenib is the standard treatment for patients with advanced hepatocellular carcinoma (HCC). However, the median overall survival (OS) benefit is only ~3 months, and sufficient biomarkers predicting treatment response are not available. The aim of the present study was to evaluate miRNA expression patterns from HCC tissue biopsies as potential biomarkers in patients under sorafenib treatment. Nineteen patients with advanced HCC treated with sorafenib were included. RNA was extracted from formalin-fixed paraffin-embedded (FFPE) liver biopsies. miRNA expression profiling of 818 mature miRNAs was performed using GeneChip® miRNA Array 2.0 (Affymetrix). Global miRNA patterns were assessed using unsupervised hierarchical clustering analysis (UCA), and specific miRNAs with correlation with disease control rate (DCR) or good OS were evaluated by pairwise supervised analyses. UCA divided the patients into three distinct groups by their miRNA expression patterns. However, DCR or OS did not correlate with these sub-groups. We have identified several miRNAs that correlated with either DCR or OS (P<0.05). However, with correction for multiple testing, these results did not reach statistical significance in this small cohort. Global miRNA analysis from very low input RNA deriving from liver biopsies showed distinctive clustering of molecular sub-groups in patients with intermediate and advanced HCC. Clinical response including OS under sorafenib did not correlate with global miRNA expression patterns, but we have identified candidate miRNAs for the prediction of DCR and OS to be evaluated in prospective studies and larger patient cohorts.


Assuntos
Antineoplásicos/uso terapêutico , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , MicroRNAs/metabolismo , Niacinamida/análogos & derivados , Compostos de Fenilureia/uso terapêutico , Biópsia por Agulha Fina , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Estudos de Viabilidade , Feminino , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/genética , Marcadores Genéticos/genética , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Niacinamida/uso terapêutico , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Reação em Cadeia da Polimerase em Tempo Real , Retrognatismo , Sorafenibe , Resultado do Tratamento
13.
Protein Sci ; 33(1): e4840, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37984441

RESUMO

Autophagy is a highly conserved cellular process that allows degradation of large macromolecules. p62/SQSTM1 is a key adaptor protein that interacts both with material to be degraded and with LC3 at the autophagosome, enabling degradation of cargos such as protein aggregates, lipid droplets and damaged organelles by selective autophagy. Dysregulation of autophagy contributes to the pathogenesis of many diseases. In this study, we investigated if the interaction of p62/SQSTM1 with LC3B could be regulated. We purified full-length p62/SQSTM1 and established an in vitro assay that measures the interaction with LC3B. We used the assay to determine the role of the different domains of p62/SQSTM1 in the interaction with LC3B. We identified a mechanism of regulation of p62/SQSTM1 where the ZZ and the PB1 domains regulate the exposure of the LIR-sequence to enable or inhibit the interaction with LC3B. A mutation to mimic the phosphorylation of a site on the ZZ domain leads to increased interaction with LC3B. Also, a small compound that binds to the ZZ domain enhances interaction with LC3B. Dysregulation of these mechanisms in p62/SQSTM1 could have implications for diseases where autophagy is affected. In conclusion, our study highlights the regulated nature of p62/SQSTM1 and its ability to modulate the interaction with LC3B through a LIR-sequence Accessibility Mechanism (LAM). Furthermore, our findings suggest the potential for pharmacological modulation of the exposure of LIR, paving the way for future therapeutic strategies.


Assuntos
Autofagossomos , Proteínas Associadas aos Microtúbulos , Autofagossomos/metabolismo , Proteína Sequestossoma-1/genética , Proteína Sequestossoma-1/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Autofagia/genética
14.
EBioMedicine ; 105: 105178, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38889481

RESUMO

BACKGROUND: The accuracy of blood-based early tumour recognition is compromised by signal production at non-tumoral sites, low amount of signal produced by small tumours, and variable tumour production. Here we examined whether tumour-specific enhancement of vascular permeability by the particular tumour homing peptide, iRGD, which carries dual function of binding to integrin receptors overexpressed in the tumour vasculature and is known to promote extravasation via neuropilin-1 receptor upon site-specific cleavage, might be useful to improve blood-based tumour detection by inducing a yet unrecognised vice versa tumour-to-blood transport. METHODS: To detect an iRGD-induced tumour-to-blood transport, we examined the effect of intravenously injected iRGD on blood levels of α-fetoprotein (AFP) and autotaxin in several mouse models of hepatocellular carcinoma (HCC) or in mice with chronic liver injury without HCC, and on prostate-specific antigen (PSA) levels in mice with prostate cancer. FINDINGS: Intravenously injected iRGD rapidly and robustly elevated the blood levels of AFP in several mouse models of HCC, but not in mice with chronic liver injury. The effect was primarily seen in mice with small tumours and normal basal blood AFP levels, was attenuated by an anti-neuropilin-1 antibody, and depended on the concentration gradient between tumour and blood. iRGD treatment was also able to increase blood levels of autotaxin in HCC mice, and of PSA in mice with prostate cancer. INTERPRETATION: We conclude that iRGD induces a tumour-to-blood transport in a tumour-specific fashion that has potential of improving diagnosis of early stage cancer. FUNDING: Deutsche Krebshilfe, DKTK, LOEWE-Frankfurt Cancer Institute.

15.
J Biol Chem ; 287(24): 20590-602, 2012 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-22511787

RESUMO

Protein kinase C-related protein kinases (PRKs) are effectors of the Rho family of small GTPases and play a role in the development of diseases such as prostate cancer and hepatitis C. Here we examined the mechanism underlying the regulation of PRK2 by its N-terminal region. We show that the N-terminal region of PRK2 prevents the interaction with its upstream kinase, the 3-phosphoinositide-dependent kinase 1 (PDK1), which phosphorylates the activation loop of PRK2. We confirm that the N-terminal region directly inhibits the kinase activity of PRK2. However, in contrast to previous models, our data indicate that this inhibition is mediated in trans through an intermolecular PRK2-PRK2 interaction. Our results also suggest that amino acids 487-501, located in the linker region between the N-terminal domains and the catalytic domain, contribute to the PRK2-PRK2 dimer formation. This dimerization is further supported by other N-terminal domains. Additionally, we provide evidence that the region C-terminal to the catalytic domain intramolecularly activates PRK2. Finally, we discovered that the catalytic domain mediates a cross-talk between the inhibitory N-terminal region and the activating C-terminal region. The results presented here describe a novel mechanism of regulation among AGC kinases and offer new insights into potential approaches to pharmacologically regulate PRK2.


Assuntos
Proteína Quinase C/metabolismo , Multimerização Proteica/fisiologia , Ativação Enzimática/fisiologia , Células HEK293 , Humanos , Fosforilação/fisiologia , Proteína Quinase C/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Piruvato Desidrogenase Quinase de Transferência de Acetil
16.
Cancer Sci ; 104(3): 398-408, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23281849

RESUMO

Epithelial-mesenchymal transition (EMT) is an important mechanism to initiate cancer invasion and metastasis. Bone morphogenetic protein (BMP)-9 is a member of the transforming growth factor (TGF)-ß superfamily. It has been suggested to play a role in cancer development in some non-hepatic tumors. In the present study, two hepatocellular carcinoma (HCC) lines, HLE and HepG2, were treated with BMP-9 in vitro, and phenotypic changes and cell motility were analyzed. In situ hybridization (ISH) and immunohistochemical analyses were performed with human HCC tissue samples in order to assess expression levels of BMP-9. In vivo, BMP-9 protein and mRNA were expressed in all the tested patients to diverse degrees. At the protein level, mildly positive (1 + ) BMP-9 staining could be observed in 25/41 (61%), and moderately to strongly positive (2 + ) in 16/41 (39%) of the patients. In 27/41 (65%) patients, the BMP-9 protein expression level was consistent with the mRNA expression level as measured by ISH. In those patients with 2 + protein level, nuclear pSmad1 expression in cancer cells was also significantly increased. Expression of BMP-9 was positively related to nuclear Snail expression and reversely correlated to cell surface E-cadherin expression, although this did not reach statistical significance. Expression levels of BMP-9 were significantly associated with the T stages of the investigated tumors and high levels of BMP-9 were detected by immunofluorescence especially at the tumor borders in samples from an HCC mouse model. In vitro, BMP-9 treatment caused a reduction of E-cadherin and ZO-1 and an induction of Vimentin and Snail expression. Furthermore, cell migration was enhanced by BMP-9 in both HCC cell lines. These results imply that EMT induced by BMP-9 is related to invasiveness of HCC.


Assuntos
Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Caderinas/metabolismo , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal , Feminino , Fator 2 de Diferenciação de Crescimento , Humanos , Masculino , Pessoa de Meia-Idade
17.
J Hepatol ; 58(5): 956-61, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23333526

RESUMO

BACKGROUND & AIMS: Soluble CD163 (sCD163) is shed in the blood circulation by activated macrophages, correlates strongly with the hepatic venous pressure gradient (HVPG) and is thereby a good indicator of portal hypertension. It is unknown whether sCD163 correlates with the risk of variceal bleeding and overall survival (OS) in patients with liver cirrhosis. We performed a prospective study to investigate if sCD163 serum levels correlate with the risk of variceal bleeding and OS in cirrhotic patients. METHODS: Patients with liver cirrhosis were prospectively enrolled and followed until death or last contact. At the day of inclusion in the study, blood samples were taken and sCD163 serum levels were assessed by ELISA (enzyme-linked immunosorbent assay). The time until the end points death and variceal bleeding was assessed and the risks of death or variceal bleeding were calculated with uni- and multivariate Cox regression analyses. RESULTS: High sCD163 levels (>4100 ng/L) were associated with death independently of the MELD (model of end stage liver disease) score, CRP (C-reactive protein), age and gender. Furthermore, high sCD163 levels were associated with gastrointestinal bleeding independently of the variceal stage and red spots. CONCLUSIONS: The sCD163 serum level is a new independent non-invasive risk factor for death and variceal bleeding in cirrhotic patients.


Assuntos
Varizes Esofágicas e Gástricas/diagnóstico , Varizes Esofágicas e Gástricas/epidemiologia , Cirrose Hepática/diagnóstico , Cirrose Hepática/mortalidade , Ativação de Macrófagos/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos CD/sangue , Antígenos de Diferenciação Mielomonocítica/sangue , Biomarcadores/sangue , Varizes Esofágicas e Gástricas/imunologia , Feminino , Humanos , Hipertensão Portal/diagnóstico , Hipertensão Portal/epidemiologia , Hipertensão Portal/imunologia , Cirrose Hepática/imunologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Receptores de Superfície Celular/sangue , Fatores de Risco , Índice de Gravidade de Doença , Taxa de Sobrevida
18.
J Hepatol ; 59(4): 769-79, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23792028

RESUMO

BACKGROUND & AIMS: The serum cell death parameters M30 and M65 and the macrophage activation marker sCD163 (soluble CD163) are elevated in patients with acute and chronic liver diseases. However, their diagnostic and prognostic potential in patients with hepatocellular carcinoma (HCC) has not yet been investigated. METHODS: Serum levels of M30, M65, and sCD163 were measured in two cohorts of HCC patients and a cohort of cirrhotic patients. The parameters were compared between patients with and without HCC and the overall survival (OS) times according to M30, M65, and sCD163 were assessed. RESULTS: M30 and M65 levels were higher in HCC patients than in cirrhotic patients (both p < 0.001). M65 was an independent parameter for non-invasive identification of HCC patients by logistic regression analysis and could supplement AFP (alpha-fetoprotein) and abdominal ultrasound in non-invasive detection of HCC patients. High M65 serum levels as well as high sCD163 concentrations were associated with an impaired prognosis in univariate Cox regression analysis. The sCD163 level was associated with OS independently of the CLIP (Cancer of the Liver Italian Program) score, the BCLC (Barcelona Clinic Liver Cancer) stage, and the CRP (C-reactive protein) level in a multivariate Cox regression model. CONCLUSIONS: Serum M65 has the potential as a new diagnostic parameter for HCC and serum sCD163 is a new prognostic parameter in HCC patients.


Assuntos
Antígenos CD/sangue , Antígenos de Diferenciação Mielomonocítica/sangue , Biomarcadores Tumorais/sangue , Carcinoma Hepatocelular/sangue , Queratina-18/sangue , Neoplasias Hepáticas/sangue , Ativação de Macrófagos , Fragmentos de Peptídeos/sangue , Receptores de Superfície Celular/sangue , Idoso , Carcinoma Hepatocelular/diagnóstico , Estudos de Casos e Controles , Morte Celular , Estudos de Coortes , Feminino , Humanos , Cirrose Hepática/sangue , Neoplasias Hepáticas/diagnóstico , Masculino , Pessoa de Meia-Idade , Prognóstico
19.
Mol Imaging ; 11(4): 272-9, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22954143

RESUMO

Different from regular small molecule contrast agents, nanoparticle-based contrast agents have a longer circulation time and can be modified with ligands to confer tissue-specific contrasting properties. We evaluated the tissue distribution of polymeric nanoparticles (NPs) prepared from human serum albumin (HSA), loaded with gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) (Gd-HSA-NP), and coated with folic acid (FA) (Gd-HSA-NP-FA) in mice by magnetic resonance imaging (MRI). FA increases the affinity of the Gd-HSA-NP to FA receptor-expressing cells. Clinical 3 T MRI was used to evaluate the signal intensities in the different organs of mice injected with Gd-DTPA, Gd-HSA-NP, or Gd-HSA-NP-FA. Signal intensities were measured and standardized by calculating the signal to noise ratios. In general, the NP-based contrast agents provided stronger contrasting than Gd-DTPA. Gd-HSA-NP-FA provided a significant contrast enhancement (CE) in the brain (p  =  .0032), whereas Gd-DTPA or Gd-HSA-NP did not. All studied MRI contrast agents showed significant CE in the blood, kidney, and liver (p < .05). Gd-HSA-NP-FA elicited significantly higher CE in the blood than Gd-HSA-NP (p  =  .0069); Gd-HSA-NP and Gd-HSA-NP-FA did not show CE in skeletal muscle and gallbladder; Gd-HSA-NP, but not Gd-HSA-NP-FA, showed CE in the cardiac muscle. Gd-HSA-NP-FA has potential as an MRI contrast agent in the brain.


Assuntos
Encéfalo/diagnóstico por imagem , Meios de Contraste , Ácido Fólico , Gadolínio DTPA , Imageamento por Ressonância Magnética , Nanopartículas , Albumina Sérica , Animais , Humanos , Masculino , Camundongos , Nanopartículas/ultraestrutura , Especificidade de Órgãos , Cintilografia , Razão Sinal-Ruído , Distribuição Tecidual
20.
BMC Med ; 10: 102, 2012 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-22967278

RESUMO

BACKGROUND: Interleukin-22 (IL-22), recently identified as a crucial parameter of pathology in experimental liver damage, may determine survival in clinical end-stage liver disease. Systematic analysis of serum IL-22 in relation to morbidity and mortality of patients with advanced liver cirrhosis has not been performed so far. METHODS: This is a prospective cohort study including 120 liver cirrhosis patients and 40 healthy donors to analyze systemic levels of IL-22 in relation to survival and hepatic complications. RESULTS: A total of 71% of patients displayed liver cirrhosis-related complications at study inclusion. A total of 23% of the patients died during a mean follow-up of 196 ± 165 days. Systemic IL-22 was detectable in 74% of patients but only in 10% of healthy donors (P < 0.001). Elevated levels of IL-22 were associated with ascites (P = 0.006), hepatorenal syndrome (P < 0.0001), and spontaneous bacterial peritonitis (P = 0.001). Patients with elevated IL-22 (>18 pg/ml, n = 57) showed significantly reduced survival compared to patients with regular (≤18 pg/ml) levels of IL-22 (321 days versus 526 days, P = 0.003). Other factors associated with reduced overall survival were high CRP (≥2.9 mg/dl, P = 0.005, hazard ratio (HR) 0.314, confidence interval (CI) (0.141 to 0.702)), elevated serum creatinine (P = 0.05, HR 0.453, CI (0.203 to 1.012)), presence of liver-related complications (P = 0.028, HR 0.258, CI (0.077 to 0.862)), model of end stage liver disease (MELD) score ≥20 (P = 0.017, HR 0.364, CI (0.159 to 0.835)) and age (P = 0.011, HR 0.955, CI (0.922 to 0.989)). Adjusted multivariate Cox proportional-hazards analysis identified elevated systemic IL-22 levels as independent predictors of reduced survival (P = 0.007, HR 0.218, CI (0.072 to 0.662)). CONCLUSIONS: In patients with liver cirrhosis, elevated systemic IL-22 levels are predictive for reduced survival independently from age, liver-related complications, CRP, creatinine and the MELD score. Thus, processes that lead to a rise in systemic interleukin-22 may be relevant for prognosis of advanced liver cirrhosis.


Assuntos
Biomarcadores/sangue , Interleucinas/sangue , Cirrose Hepática/diagnóstico , Cirrose Hepática/mortalidade , Adulto , Idoso , Estudos de Coortes , Feminino , Seguimentos , Humanos , Cirrose Hepática/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Soro/química , Análise de Sobrevida , Regulação para Cima , Interleucina 22
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