RESUMO
Two common obstacles limiting the performance of data-driven algorithms in digital histopathology classification tasks are the lack of expert annotations and the narrow diversity of datasets. Multi-instance learning (MIL) can address the former challenge for the analysis of whole slide images (WSI), but performance is often inferior to full supervision. We show that the inclusion of weak annotations can significantly enhance the effectiveness of MIL while keeping the approach scalable. An analysis framework was developed to process periodic acid-Schiff (PAS) and Sirius Red (SR) slides of renal biopsies. The workflow segments tissues into coarse tissue classes. Handcrafted and deep features were extracted from these tissues and combined using a soft attention model to predict several slide-level labels: delayed graft function (DGF), acute tubular injury (ATI), and Remuzzi grade components. A tissue segmentation quality metric was also developed to reduce the adverse impact of poorly segmented instances. The soft attention model was trained using 5-fold cross-validation on a mixed dataset and tested on the QUOD dataset containing n = 373 PAS and n = 195 SR biopsies. The average ROC-AUC over different prediction tasks was found to be 0.598 ± 0.011 , significantly higher than using only ResNet50 ( 0.545 ± 0.012 ), only handcrafted features ( 0.542 ± 0.011 ), and the baseline ( 0.532 ± 0.012 ) of state-of-the-art performance. In conjunction with soft attention, weighting tissues by segmentation quality has led to further improvement ( A U C = 0.618 ± 0.010 ) . Using an intuitive visualisation scheme, we show that our approach may also be used to support clinical decision making as it allows pinpointing individual tissues relevant to the predictions.
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The utilization of kidneys from donors with acute kidney injury (AKI) is often limited by unpredictable post-transplantation outcomes. The aim of our study was to identify protein mediators implicated in either recovery or failure of these organs. Forty kidney biopsies from donors with (20) and without AKI (20) were selected and then subdivided according to the post-transplant outcome defined as a threshold of 45 ml/min for the eGFR at 1 year from transplantation. Tissue homogenates were analysed by western blot to assess how the levels of 17 pre-selected proteins varied across the four groups. Samples from AKI kidneys with a poor outcome showed a fourfold increase in the levels of PPARg and twofold reduction of STAT1 compared to the other groups (p < 0.05). On the contrary, antioxidant enzymes including TRX1 and PRX3 were increased in the AKI kidneys with a good outcome (p < 0.05). An opposite trend was observed for the detoxifying enzyme GSTp which was significantly increased in the AKI group with poor versus good outcome (p < 0.05). The importance of lipid metabolism (PPARg) and inflammatory signals (STAT1) in the function recovery of these kidneys hints to the therapeutical targeting of the involved pathways in the setting of organ reconditioning.
Assuntos
Injúria Renal Aguda , Transplante de Rim , Humanos , Transplante de Rim/efeitos adversos , PPAR gama , Sobrevivência de Enxerto , Doadores de Tecidos , Rim/patologia , Injúria Renal Aguda/patologia , Biópsia , Estudos RetrospectivosRESUMO
BACKGROUND: There is a need to improve the treatment of prostate cancer (PCa) and reduce treatment side effects. Vascular-targeted photodynamic therapy (VTP) is a focal therapy for low-risk low-volume localised PCa, which rapidly disrupts targeted tumour vessels. There is interest in expanding the use of VTP to higher-risk disease. Tumour vasculature is characterised by vessel immaturity, increased permeability, aberrant branching and inefficient flow. FRT alters the tumour microenvironment and promotes transient 'vascular normalisation'. We hypothesised that multimodality therapy combining fractionated radiotherapy (FRT) and VTP could improve PCa tumour control compared against monotherapy with FRT or VTP. METHODS: We investigated whether sequential delivery of FRT followed by VTP 7 days later improves flank TRAMP-C1 PCa tumour allograft control compared to monotherapy with FRT or VTP. RESULTS: FRT induced 'vascular normalisation' changes in PCa flank tumour allografts, improving vascular function as demonstrated using dynamic contrast-enhanced magnetic resonance imaging. FRT followed by VTP significantly delayed tumour growth in flank PCa allograft pre-clinical models, compared with monotherapy with FRT or VTP, and improved overall survival. CONCLUSION: Combining FRT and VTP may be a promising multimodal approach in PCa therapy. This provides proof-of-concept for this multimodality treatment to inform early phase clinical trials.
Assuntos
Neovascularização Patológica/terapia , Fotoquimioterapia/métodos , Neoplasias da Próstata/terapia , Animais , Linhagem Celular Tumoral , Terapia Combinada , Fracionamento da Dose de Radiação , Células Endoteliais da Veia Umbilical Humana , Humanos , Masculino , Camundongos , Neoplasias da Próstata/irrigação sanguínea , Análise de Sobrevida , Microambiente Tumoral , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: Brain-derived neurotrophic factor (BDNF) has emerged as a novel angiogenic factor, and yet its impact on tumorigenesis is unclear. This study aimed at investigating the roles of BDNF in angiogenesis and tumor development. EXPERIMENTAL DESIGN: BDNF was overexpressed in a mouse endothelial cell (EC) line by stable transfection, and angiogenic properties of the transfectants were assessed. Microarray analysis was employed to explore the molecular pathways. The impact of modulating BDNF levels in two mouse EC lines on tumorigenic potential of a transformed mouse liver cell line was evaluated by an in vivo cotransplantation model. BDNF and tropomyosin receptor kinase B (TrkB) protein levels were determined in 50 pairs of human hepatocellular carcinoma (HCC) tissues by Western blotting and immunohistochemistry. Survival analysis was carried out to determine their clinical significance. RESULTS: Overexpression of BDNF could promote EC proliferation, migration, invasion, and survival. Microarray and molecular studies showed that RhoA, caspase-9, caspase-3, growth arrest specific 6, and VEGF could mediate BDNF/TrkB-induced angiogenesis. The cotransplantation experiment showed that high BDNF-expressing ECs could facilitate tumor angiogenesis and growth, whereas knockdown of BDNF by short hairpin RNAs impaired such effects. Furthermore, examination on human HCC tissues revealed upregulation of BDNF and TrkB protein levels in 46.0% and 33.3% of the cases studied, respectively. Immunohistochemistry disclosed strong BDNF reactivity in both tumor and endothelial cells. High TrkB expression was associated with shorter overall survival. CONCLUSIONS: BDNF/TrkB system was crucial for tumor angiogenesis and growth, which may represent a potential target for antiangiogenic therapy in HCC.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/fisiologia , Carcinoma Hepatocelular/patologia , Transformação Celular Neoplásica/genética , Neoplasias Hepáticas/patologia , Neovascularização Patológica/genética , Animais , Fator Neurotrófico Derivado do Encéfalo/antagonistas & inibidores , Fator Neurotrófico Derivado do Encéfalo/genética , Carcinoma Hepatocelular/irrigação sanguínea , Carcinoma Hepatocelular/genética , Transformação Celular Neoplásica/efeitos dos fármacos , Células Cultivadas , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Neoplasias Hepáticas/irrigação sanguínea , Neoplasias Hepáticas/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neovascularização Patológica/patologia , RNA Interferente Pequeno/farmacologia , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The present study investigated the effect of mammalian target of rapamycin (mTOR) inhibition on HCC cells in vitro and in vivo, either alone or in combination with cytotoxic agents. In vitro, HCC cell lines were exposed to RAD001, an mTOR inhibitor, either alone or in combination with cisplatin. Alone, RAD001 suppressed cell proliferation in all cell lines tested, but did not induce apoptosis. RAD001 in combination with cisplatin induced a significant increase in the number of apoptotic cells, downregulated the expression of pro-survival molecules, Bcl-2, survivin and cyclinD1, and increased the cleavage of PARP, compared to RAD001 or cisplatin alone. Transfection of p53 into the Hep3B cell line increased the sensitivity of tumor cells to cisplatin. The suppression of HCC tumor growth in vivo was enhanced by RAD001 combined with cisplatin, accompanied by a significant increase in the number of apoptotic cells in tumor tissues. This study demonstrates that inhibition of mTOR suppresses tumor growth and sensitizes tumor cells to chemocytotoxic agents.
Assuntos
Antineoplásicos/farmacologia , Apoptose , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/metabolismo , Proteínas Quinases/metabolismo , Animais , Linhagem Celular Tumoral , Cisplatino/farmacologia , Ciclina D1/biossíntese , Resistencia a Medicamentos Antineoplásicos , Genes p53 , Humanos , Proteínas Inibidoras de Apoptose , Masculino , Camundongos , Camundongos Nus , Proteínas Associadas aos Microtúbulos/biossíntese , Proteínas de Neoplasias/biossíntese , Transplante de Neoplasias , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Survivina , Serina-Treonina Quinases TORRESUMO
UNLABELLED: Increasing evidence has revealed the importance of cancer stem cells (CSCs) in carcinogenesis. Although liver CSCs have been identified in hepatocellular carcinoma (HCC) cell lines, no data have shown the presence of these cells in human settings. The present study was designed to delineate CSCs serially from HCC cell lines, human liver cancer specimens to blood samples, using CD90 as a potential marker. The number of CD90(+) cells increased with the tumorigenicity of HCC cell lines. CD45(-)CD90(+) cells were detected in all the tumor specimens, but not in the normal, cirrhotic, and parallel nontumorous livers. In addition, CD45(-)CD90(+) cells were detectable in 90% of blood samples from liver cancer patients, but none in normal subjects or patients with cirrhosis. A significant positive correlation between the number of CD45(-)CD90(+) cells in the tumor tissues and the number of CD45(-)CD90(+) cells in the blood samples was identified. CD90(+) cells sorted from cell lines and CD45(-)CD90(+) cells from the tumor tissues and blood samples of liver cancer patients generated tumor nodules in immunodeficient mice. Serial transplantation of CD90(+) cells from tumor xenografts generated tumor nodules in a second and subsequently third batch of immunodeficient mice. Treatment of CD90(+) CSCs with anti-human CD44 antibody induced cell apoptosis in a dose-dependent manner. CONCLUSION: Identification of CD45(-)CD90(+) CSCs in both tumor tissues and circulation suggests that CD45(-)CD90(+) could be used as a marker for human liver cancer and as a target for the diagnosis and therapy of this malignancy.
Assuntos
Carcinoma Hepatocelular/diagnóstico , Neoplasias Hepáticas/diagnóstico , Células Neoplásicas Circulantes/química , Células-Tronco Neoplásicas/química , Antígenos Thy-1/análise , Animais , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica/patologia , Citometria de Fluxo , Humanos , Antígenos Comuns de Leucócito/análise , Neoplasias Hepáticas/patologia , Camundongos , Camundongos SCID , Células Neoplásicas Circulantes/patologia , Células-Tronco Neoplásicas/patologiaRESUMO
The present study investigated the effect of YC-1, a novel anti-cancer agent, on the chemo-sensitivity of hepatocellular carcinoma (HCC). YC-1 was administered with chemo-cytotoxic drug, cisplatin, both in vitro and in vivo. YC-1 alone downregulated the expression of phosphorylated form of signal transducers and activators of transcription 3 (P-Stat3[705]), a key mediator in chemo-resistance. When combined with cisplatin, YC-1 further promoted tumor cell apoptosis, decreased the expression of P-Stat3(705), Bcl-xL, CyclinD1 and survivin, and induced the cleavage of caspase 9 and PARP. Overexpression of Stat3 reversed YC-1 induced cell death. YC-1 inhibited Stat3 activity by enhancing the polyubiquitination of P-Stat3(705) induced by cisplatin. In the in vivo setting, YC-1 combined with cisplatin remarkably suppressed tumor growth in a HCC xenograft model, and this effect was also accompanied by YC-1 mediated downregulation of P-Stat3(705), Bcl-xL, Cyclin D1 and survivin, and induction of cleaved caspase 9 and PARP in the tumor tissues. In conclusion, the present study demonstrated a novel anti-cancer effect of YC-1 in enhancing chemo-sensitivity of HCC cells to cisplatin through a Stat3 dependent manner. This finding provides insight into design of a new therapeutic strategy to improve efficacy of chemotherapy in HCC patients.
Assuntos
Antineoplásicos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Cisplatino/farmacologia , Indazóis/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Proteínas de Neoplasias/antagonistas & inibidores , Fator de Transcrição STAT3/antagonistas & inibidores , Animais , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Caspase 9/biossíntese , Caspase 9/genética , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Ciclina D , Ciclinas/biossíntese , Ciclinas/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Indazóis/uso terapêutico , Proteínas Inibidoras de Apoptose , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Neoplasias Hepáticas Experimentais/metabolismo , Neoplasias Hepáticas Experimentais/patologia , Camundongos , Proteínas Associadas aos Microtúbulos/biossíntese , Proteínas Associadas aos Microtúbulos/genética , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/biossíntese , Poli(ADP-Ribose) Polimerases/genética , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Fator de Transcrição STAT3/metabolismo , Survivina , Ubiquitinação/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , Proteína bcl-X/biossíntese , Proteína bcl-X/genéticaRESUMO
This study aims to investigate the potential role of endogenous interleukin (IL)-10 in long-term liver allograft survival induced by delayed immunosuppression (FK506 days 2-7). Liver transplantation was performed by using Dark Agouti and Lewis rats as donors and recipients, respectively. The delayed immunosuppression protocol induced indefinite allograft survival. A transient upregulation of plasma IL-10 levels was detected in the nontreatment and FK506 treatment groups. Macrophages were found to be one of the major sources of IL-10 produced from the liver allografts. Administration of IL-10-neutralizing antibody shortened the long-term isograft survival and FK506-induced indefinite allograft survival, particularly in the FK506 group. Damaged liver graft histology and increase of plasma alanine aminotransferase levels were detected in the groups with IL-10 antibody treatment. In an ex vivo setting, IL-10 recombinant protein augmented the expression of Foxp3, downregulated the expression of IL-2 and interferon gamma, and induced the generation of CD4(+)CD25(+)Foxp3(+) and CD8(+)CD25(+)Foxp3(+) cells, but this effect was blocked by the administration of IL-10 antibody. Finally, administration of IL-10 recombinant protein after the decline of endogenous IL-10 levels improved allograft survival, and a 100% long-term allograft survival was achieved by the combination of IL-10 with low-dose FK506. In conclusion, the delayed immunosuppression could induce long-term liver allograft survival in the presence of endogenous IL-10 produced by the tissue macrophages. Supplementary exogenous IL-10 administration combined with low-dose immunosuppressive drug may be a useful strategy to induce long-term liver allograft survival.
Assuntos
Sobrevivência de Enxerto/imunologia , Terapia de Imunossupressão/métodos , Interleucina-10/imunologia , Transplante de Fígado/imunologia , Tacrolimo/uso terapêutico , Animais , Técnicas de Cultura de Células , Esquema de Medicação , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Sobrevivência de Enxerto/efeitos dos fármacos , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/imunologia , Testes de Função Hepática , RNA/genética , RNA/isolamento & purificação , Ratos , Ratos Endogâmicos Lew , Ratos Endogâmicos , Tacrolimo/administração & dosagem , Fatores de Tempo , Transplante HomólogoRESUMO
The present study investigated the significance of the serum brain-derived neurotrophic factor (BDNF) and platelets in relation to the clinicopathological features of hepatocellular carcinoma (HCC) patients. Localization of the BDNF expression in human HCC tissues was performed by immunohistochemistry. The measurement of soluble BDNF in the serum was performed by enzyme-linked immunosorbent assay. BDNF was expressed in the cytoplasm of the tumor cells. A positive correlation between the tissue and serum levels of BDNF was identified in the HCC patients. The serum levels of BDNF were positively correlated with the platelet counts in the HCC patients. A higher level of serum BDNF was significantly correlated with a tumor size >5 cm, poorly differentiated HCC, the presence of microsatellite tumor nodules, and the absence of cirrhosis in the non-tumorous tissues. A higher level of the serum BDNF/platelet ratio was associated with a poorer disease-free survival after hepatic resection. This study suggested that the tumor cell was a source of serum BDNF in HCC. A higher serum BDNF level was associated with a more advanced tumor status in the HCC patients. The interaction between serum BDNF and platelets might play an important role in HCC tumor progression.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Contagem de Plaquetas , Plaquetas/fisiologia , Carcinoma Hepatocelular/mortalidade , Intervalo Livre de Doença , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imuno-Histoquímica , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , PrognósticoRESUMO
HYPOTHESIS: Administration of cardiotrophin 1 (CT-1) can treat experimental fulminant hepatic failure (FHF). DESIGN: Rat model with FHF induced by D-galactosamine (D-gal). SETTING: Fulminant hepatic failure is a rapidly progressive disease that lacks effective nonsurgical treatment. Cardiotrophin 1 is a member of the interleukin 6 family that can protect cells from damage in some animal disease models. ANIMALS: A rat model of FHF was induced by an intraperitoneal injection of D-gal (1.4 g/kg of body weight). Cardiotrophin 1 was administered at different time points after D-gal injection. RESULTS: Administration of CT-1 at 12 and 18 hours had a survival rate of 80% (12/15) and 70% (7/10), respectively, which was significantly higher than that of nontreatment (28% [5/18]). In addition, improvement of liver histologic findings, shortening of activated clotting time, and decrease in serum levels of total bilirubin and alanine aminotransferase were detected with CT-1 treatment. Administration of CT-1 decreased apoptotic cells and increased Ki-67 cells in the liver tissues. In vitro, CT-1 administration significantly decreased apoptotic cells and sequentially down-regulated the expression of proapoptotic molecules and up-regulated the expression of antiapoptotic molecules at different culture periods. D-galactosamine culture induced morphologic damage in a hepatocyte cell line, which was greatly improved by CT-1 administration. In addition, CT-1-treated cells demonstrated increased expression of glycoprotein 130 and up-regulation of cyclin D1 and heat shock protein 90. CONCLUSION: Cardiotrophin 1 may improve the outcome of D-gal-induced FHF through its effects on antiapoptosis and cell repair.
Assuntos
Apoptose/efeitos dos fármacos , Citocinas/farmacologia , Hepatócitos/efeitos dos fármacos , Falência Hepática Aguda/tratamento farmacológico , Análise de Variância , Animais , Western Blotting , Linhagem Celular , Modelos Animais de Doenças , Citometria de Fluxo , Galactosidases , Falência Hepática Aguda/patologia , Testes de Função Hepática , Masculino , Ratos , Taxa de SobrevidaRESUMO
The present study aimed to investigate the therapeutic efficacy of combining vascular endothelial growth factor (VEGF) receptor blockade using tyrosine kinase inhibitor PTK787 with hypoxia for the treatment of hepatocellular carcinoma (HCC). The in vivo effects of the treatments were determined in a rat orthotopic HCC model, in which hypoxia was generated by hepatic artery ligation (HAL). Compared with HAL alone, PTK787 combined with HAL significantly prolonged the animal survival, reduced the tumor size, induced more tumor tissue necrosis and apoptosis, and down-regulated the expression of von Willebrand factor. The mechanism was explored in vitro using murine HCC and endothelial cell lines, respectively. PTK787 combined with hypoxia decreased the expression of VEGF and VEGF receptors in both cell lines and suppressed the cell viability by induction of cell cycle arrest and promotion of apoptosis. Up-regulation of cleaved form caspase-9 and down-regulation of Bcl-2 and cyclin D1 were detected with the combined treatment. Hypoxia sensitized endothelial cells to the inhibitory effect of PTK787 on forming tubular-like structure. The motility of tumor cells was inhibited by hypoxia and the combined approach, with down-regulation of Rac1, Rho, and phosphorylated Akt expression. However, in the endothelial cells, the combined treatment inhibited the hypoxia-enhanced cell motility, with suppressed Rac1, Rho, and phosphorylated Akt expression. In conclusion, PTK787 combined with hypoxia achieved a better therapeutic efficacy than hypoxia alone through enhancing hypoxia-induced antitumor cell effect and preventing the activation of angiogenic process.
Assuntos
Inibidores da Angiogênese/farmacologia , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Ftalazinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Piridinas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Hipóxia Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/enzimologia , Células Endoteliais/metabolismo , Neoplasias Hepáticas Experimentais/irrigação sanguínea , Neoplasias Hepáticas Experimentais/enzimologia , Neoplasias Hepáticas Experimentais/patologia , Masculino , Camundongos , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/enzimologia , Neovascularização Patológica/patologia , Ratos , Ratos Endogâmicos BUF , Fator A de Crescimento do Endotélio Vascular/sangueRESUMO
Inhibition of HIF-1alpha activity provides an important strategy for the treatment of cancer. Recently, 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) has been identified as an anti-HIF-1alpha drug in cancer therapy with unclear molecular mechanism. In the present study, we aimed to investigate the effect and mechanism of YC-1 on HIF-1alpha in a hepatocellular carcinoma cell line under hypoxic condition, which was generated by incubating cells with 0.1% O(2). The phenotypic and molecular changes of cells were determined by cell proliferation assay, apoptosis assay, luciferase promoter assay, and Western blot analysis. YC-1 arrested tumor cell growth in a dose-dependent manner, whereas it did not induce cell apoptosis. Hypoxia-induced upregulation of HIF-1alpha was suppressed by YC-1 administration. YC-1 inhibited HIF-1alpha protein synthesis under normoxia and affected protein stability under hypoxia. YC-1 suppressed the expression of total and phosphorylated forms of murine double minute 2 (Mdm2), whereas this inhibitory effect was blocked by overexpression of Mdm2. In conclusion, YC-1 suppressed both protein synthesis and stability of HIF-1alpha in HCC cells, and its inhibitory effects on HIF-1alpha were dependent on Mdm2.
Assuntos
Antineoplásicos/farmacologia , Carcinoma Hepatocelular/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Indazóis/farmacologia , Neoplasias Hepáticas/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/fisiologia , Carcinoma Hepatocelular/patologia , Hipóxia Celular , Linhagem Celular Tumoral , Regulação para Baixo , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/biossíntese , Neoplasias Hepáticas/patologiaRESUMO
Platelets are an important place for the storage of angiogenic factors, such as vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF). The present study aims to investigate the interaction between BDNF-TrkB pathway and platelet activation during tumor development. In an orthotopic hepatocellular carcinoma (HCC) model, increased levels of serum and plasma BDNF were detected with tumor progression. Higher numbers of CD62P+ and TrkB+ platelets were found in the tumor-bearing rats. In the in vitro setting, tumor-conditioned-medium (TCM) and BDNF recombinant protein stimulated CD62P upregulation and subsequent BDNF release in the freshly isolated platelets, whereas this effect could be inhibited by TrkB blockade. TCM and BDNF culture augmented the expression of heat shock protein 90 (Hsp90) in the platelets, which could be reversed by TrkB blockade. In conclusion, this study suggested the presence of BDNF-TrkB autocrine loop in platelets and its importance in regulating platelet activation during tumor development.
Assuntos
Comunicação Autócrina , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Ativação Plaquetária , Receptor trkB/metabolismo , Animais , Linhagem Celular Tumoral , Separação Celular , Masculino , Ligação Proteica , Ratos , Ratos Endogâmicos BUFRESUMO
A family of Group 4 post-metallocene catalysts, supported by fluorine-functionalized tridentate ligands with the fluorine substituent in the locality of the metal center, is described. For the first time, the contentious C-H...F-C interaction has been characterized by a neutron diffraction study, which has allowed the position of the hydrogen atoms to be accurately determined. The nature of the weak intramolecular C-H...F-C contacts in these complexes in solution and the solid state was probed by using multinuclear NMR spectroscopy in tandem with neutron and X-ray crystallography. Evidence is presented to demonstrate that the spectroscopic C-H...F-C coupling occurs "through-space" rather than "through-bond" or by MF coordination. The titanium catalysts exhibit excellent activities and high co-monomer incorporation in olefin polymerization. The observed intramolecular C-H...F-C interactions are important with regards to potential applications in polyolefin catalysis because they substantiate the proposed ortho-F...H(beta) ligand-(polymer chain) contacts derived from DFT calculations for the remarkable fluorinated phenoxyimine Group 4 catalysts. Compared with agostic and co-catalyst...metal contacts, weak attractive noncovalent interactions between a polymer chain and a judiciously designed "active" ligand is a new concept in polyolefin catalysis.