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1.
Infect Agent Cancer ; 19(1): 21, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38693556

RESUMO

AIMS: This study compared the prevalences of metabolic syndrome and of cardiac or kidney comorbidities among patients with hepatocellular carcinoma (HCC) associated with metabolic dysfunction-related fatty liver disease (MAFLD), chronic infection with hepatitis B or C virus (HBV or HCV), or the combination of MAFLD and chronic HBV infection. METHODS: Medical records were retrospectively analyzed for patients with HCC who underwent hepatectomy between March 2013 and March 2023. Patients with HCC of different etiologies were compared in terms of their clinicodemographic characteristics and laboratory data before surgery. RESULTS: Of the 2422 patients, 1,822 (75.2%) were chronically infected with HBV without MAFLD and HCV, 415 (17.2%) had concurrent MAFLD and chronic HBV infection but no HCV infection, 121 (5.0%) had MAFLD without hepatitis virus infection, and 64 (2.6%) were chronically infected with HCV in the presence or absence of MAFLD and HBV infection. Compared to patients chronically infected with HBV without MAFLD and HCV, those with MAFLD but no hepatitis virus infection showed significantly lower prevalence of cirrhosis, ascites, portal hypertension, alpha-fetoprotein concentration ≥ 400 ng/mL, tumor size > 5 cm, multinodular tumors and microvascular invasion. Conversely, they showed significantly higher prevalence of metabolic syndrome, hypertension, type 2 diabetes, abdominal obesity, history of cardiovascular disease, T-wave alterations, hypertriglyceridemia and hyperuricemia, as well as higher risk of arteriosclerotic cardiovascular disease. Compared to patients with MAFLD but no hepatitis virus infection, those with concurrent MAFLD and chronic infection with HBV showed significantly higher prevalence of cirrhosis, ascites and portal hypertension, but significantly lower prevalence of hypertension and history of cardiovascular disease. Compared to patients with other etiologies, those chronically infected with HCV in the presence or absence of MAFLD and HBV infection, showed significantly higher prevalence of cirrhosis, portal hypertension, ascites, and esophagogastric varices. CONCLUSION: Patients with HCC associated with MAFLD tend to have a background of less severe liver disease than those with HCC of other etiologies, but they may be more likely to suffer metabolic syndrome or comorbidities affecting the heart or kidneys.

2.
Lancet Reg Health West Pac ; 31: 100617, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36879786

RESUMO

Background: KL-A167 is a fully humanized monoclonal antibody targeting programmed cell death-ligand 1. This phase 2 study aimed to evaluate the efficacy and safety of KL-A167 in Chinese patients with previously treated recurrent or metastatic (R/M) nasopharyngeal carcinoma (NPC). Methods: This was a multicentre, single-arm, phase 2 study of KL-A167 in R/M NPC (KL167-2-05-CTP) (NCT03848286), conducted at 42 hospitals across the People's Republic of China. Eligible patients had histologically confirmed non-keratinising R/M NPC, and had failed at least two lines of chemotherapy. Patients received KL-A167 900mg intravenously once every 2 weeks until confirmed disease progression, intolerable toxicity, or withdrawal of informed consent. The primary endpoint was objective response rate (ORR) assessed by the independent review committee (IRC) according to RECIST v1.1. Findings: Between Feb 26th, 2019 and Jan 13th, 2021, 153 patients were treated. Totally, 132 patients entered full analysis set (FAS) and were evaluated for the efficacy. As of data cutoff date on Jul 13th, 2021, the median follow-up time was 21.7 months (95%CI 19.8-22.5). For FAS population, the IRC-assessed ORR was 26.5% (95%CI 19.2-34.9%), and disease control rate (DCR) was 56.8% (95%CI 47.9-65.4%). Median progression-free survival (PFS) was 2.8 months (95%CI 1.5-4.1) . Median duration of response was 12.4 months (95%CI 6.8-16.5), and median overall survival (OS) was 16.2 months (95%CI 13.4-21.3). When using the cutoff of 1000 copies/ml, 5000 copies/ml and 10,000 copies/ml for plasma EBV DNA titer, baseline low plasma EBV DNA was consistently related with better DCR, PFS and OS. Dynamic change of plasma EBV DNA was significantly associated with ORR and PFS. Among 153 patients, treatment related-adverse events (TRAEs) occurred in 73.2% of patients, and grade ≥3 TRAEs were in 15.0% of patients. No TRAE leading to death was reported. Conclusion: In this study, KL-A167 showed promising efficacy and an acceptable safety profile in patients with previously treated R/M NPC. Baseline plasma EBV DNA copy number might be a potentially useful prognostic biomarker for KL-A167 treatment, and post-treatment EBV DNA decrease might be correlated with better response to KL-A167. Funding: Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd., China National Major Project for New Drug Innovation (2017ZX09304015).

3.
Analyst ; 147(12): 2802-2808, 2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35611629

RESUMO

Surface enhanced Raman scattering (SERS) is an ultrasensitive analytic technique. However, the application of SERS in quantitative analysis usually suffers from poor reliability due to the limitations of currently developed SERS substrates. In the present work, aggregated gold nanoparticles (a-AuNPs) fabricated by Ca2+-mediated assembly are dispersed in polyvinyl alcohol solution to prepare a novel hydrogel SERS chip through a physical crosslinking method. Taking advantage of the uniform distribution of SERS active a-AuNPs in the three-dimension hydrogel and the excellent barrier effect of hydrogel towards oxygen and macromolecules, the obtained hydrogel SERS chips show many outstanding advantages including high sensitivity, good repeatability, long-term stability, and a robust anti-interference ability. These advantages enable hydrogel SERS chips to be used to quantitatively analyse some complex samples without complex sample preprocessing. As a model, the hydrogel SERS chips are used for the detection of triazophos and phosmet in orange samples. The good recoveries suggest good applicability of the hydrogel SERS chips in food safety detection. This work provides a reliable and convenient platform for the quick detection and on-site monitoring of chemical contaminants and would promote greatly the performance of SERS techniques in quantitative analysis.


Assuntos
Nanopartículas Metálicas , Praguicidas , Ouro/química , Hidrogéis , Nanopartículas Metálicas/química , Compostos Organofosforados , Praguicidas/análise , Reprodutibilidade dos Testes , Análise Espectral Raman/métodos
4.
Front Pharmacol ; 13: 875372, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35614940

RESUMO

The PI3K-Akt-mTOR pathway is a viable target for cancer treatment and can be used to treat various malignant tumours, including follicular lymphoma and breast cancer. Both enzymes, PI3K and mTOR, are critical in this pathway. Hence, in recent years, an array of inhibitors targeting these two targets have been studied, showing dual PI3K/mTOR inhibition compared with single targeting small molecule inhibitors. Inhibitors not only inhibit cell proliferation but also promote cell apoptosis. These inhibitors show high potency and little drug resistance even at low doses, suggesting that PI3K/mTOR inhibitors are promising cancer drugs. Herein, we summarised the recent research of PI3K/mTOR dual inhibitors-for example, structure-activity relationship, pharmacokinetics, and clinical practice, and briefly commented on them. Clinical Trial Registration: https://clinicaltrials.gov.

5.
Biomed Pharmacother ; 151: 113116, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35598365

RESUMO

Focal adhesion kinase (FAK, also known as PTK2) is a tyrosine kinase that regulates integrin and growth factor signaling pathways and is involved in the migration, proliferation and survival of cancer cells. FAK is a promising target for cancer treatment. Many small molecule FAK inhibitors have been identified and proven in both preclinical and clinical studies to be effective inhibitors of tumor growth and metastasis. There are many signaling pathways, such as those involving FAK, Src, AKT, MAPK, PI3K, and EGFR/HER-2, that provide survival signals in cancer cells. Dual inhibitors that simultaneously block FAK and another factor can significantly improve efficacy and overcome some of the shortcomings of single-target inhibitors, including drug resistance. In this review, the antitumor mechanisms and research status of dual inhibitors of FAK and other targets, such as Pyk2, IGF-IR, ALK, VEGFR-3, JAK2, EGFR, S6K1, and HDAC2, are summarized, providing new ideas for the development of effective FAK dual-target preparations.


Assuntos
Proteína-Tirosina Quinases de Adesão Focal , Neoplasias , Transdução de Sinais , Proteína-Tirosina Quinases de Adesão Focal/antagonistas & inibidores , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Neoplasias/tratamento farmacológico , Fosforilação , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico
6.
J Clin Transl Hepatol ; 10(1): 147-158, 2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35233384

RESUMO

The proportions of patients with hepatocellular carcinoma (HCC) involving portal vein tumor thrombus (PVTT) varies greatly in different countries or regions, ranging from 13% to 45%. The treatment regimens for PVTT recommended by HCC guidelines in different countries or regions also vary greatly. In recent years, with the progress and development of surgical concepts, radiotherapy techniques, systematic therapies (for example, VEGF inhibitors, tyrosine kinase inhibitors and immune checkpoint inhibitors), patients with HCC involving PVTT have more treatment options and their prognoses have been significantly improved. To achieve the maximum benefit, both clinicians and patients need to think rationally about the indications of treatment modalities, the occurrence of severe adverse events, and the optimal fit for the population. In this review, we provide an update on the treatment modalities available for patients with HCC involving PVTT. Trials with large sample size for patients with advanced or unresectable HCC are also reviewed.

7.
Front Oncol ; 11: 737497, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34745958

RESUMO

Hepatocellular carcinoma (HCC) is one of the most common malignant tumor in the world and its incidence is increasing in many countries. In recent years, with the deepening understanding of the immune and pathological mechanisms of HCC, immunotherapy based on the regulation of tumor immune microenvironment has become a new treatment choice for patients with HCC. Immune checkpoint inhibitors (ICIs) targeting programmed death protein-1, programmed death protein-ligand-1, or cytotoxic T-lymphocyte-associated antigen 4 are the most widely used. Instead of general immune-enhancing therapies, ICIs can reactivate anti-tumor immune responses by disrupting co-inhibitory T cell signaling. In this review, the research progress and existing problems of ICIs in the treatment of HCC in recent years are reviewed.

8.
Aging (Albany NY) ; 11(22): 10154-10166, 2019 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-31740624

RESUMO

Cervical squamous cell carcinoma (CSCC) is one of the most commonly occurring gynecological malignancies. Because CSCC is a biologically heterogeneous disease, its prognosis varies. Therefore, identifying prognostic biomarkers that reflect its biological heterogeneity could lead to better interventions for patients with a poor prognosis. This study used the ESTIMATE algorithm to identify immune related prognostic genes within the tumor microenvironment of CSCC. The results revealed that high immune scores were associated with better overall survival (P = 0.029). Differential expression analysis revealed 384 intersection genes influencing both the immune and stromal scores. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses showed the 384 intersection genes to be mainly enriched for T cell activation, the region of the membrane, carbohydrate binding, and cytokine-cytokine receptor interaction. Among them, 149 immune genes were predictive of overall survival in CSCC. These findings provide a more comprehensive understanding of immune genes within the tumor microenvironment as well as a list of immune genes prognostic in CSCC.


Assuntos
Carcinoma de Células Escamosas/genética , Regulação Neoplásica da Expressão Gênica , Microambiente Tumoral/genética , Neoplasias do Colo do Útero/genética , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Bases de Dados Genéticas , Feminino , Perfilação da Expressão Gênica , Humanos , Prognóstico , Taxa de Sobrevida , Neoplasias do Colo do Útero/mortalidade , Neoplasias do Colo do Útero/patologia
9.
Bioresour Technol ; 280: 313-324, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30780091

RESUMO

Spent mushroom substrate (SMS) and textile dyeing sludge (TDS) were (co-)combusted in changing heating rates, blend ratios and temperature. The increased blend ratio improved the ignition, burnout and comprehensive combustion indices. A comparison of theoretical and experimental thermogravimetric curves pointed to significant interactions between 350 and 600 °C. High content of Fe2O3 in TDS ash may act as catalysis at a high temperature. Ignition activation energy was lower for TDS than SMS due to its low thermal stability. 40% SMS appeared to be the optimal blend ratio that significantly decreased the activation energy, as was verified by the response surface methodology. D3 model best described the (co-)combustions. SMS led to more NO and NO2 emissions at about 300 °C and less HCN emission than did TDS. The addition of 40% SMS to TDS lowered SO2 emission. The co-combustion of TDS and SMS appeared to enhance energy generation and emission reduction.


Assuntos
Agaricales , Esgotos/química , Têxteis , Termodinâmica , Catálise , Temperatura Alta , Cinética
10.
J Invest Dermatol ; 125(3): 560-6, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16117799

RESUMO

Chronic exposure to ultraviolet radiation including ultraviolet A (315-400 nm) (UVA) may cause photocarcinogenesis and photoaging. The UVA-induced production of reactive oxygen species (ROS) and the resultant oxidative stress exposure play an important role in these biological processes. Here we have investigated the role of phagocyte oxidase (PHOX, gp91phox) in the production of ROS, redox status change, and apoptosis after UVA exposure by using gp91phox-deficient (gp91phox-/-) primary keratinocytes. UVA radiation resulted in increased ROS production and oxidation of reduced glutathione (GSH) to its oxidized form (GSSG). The presence of diphenylene iodonium (DPI) inhibited ROS production by UVA. In comparison with wild-type cells, gp91phox-/- cells produced slightly less ROS and GSH oxidation. UVA radiation induced apoptosis in wild-type keratinocytes as detected by phosphatidylserine (PS) translocation, caspase activation, and DNA fragmentation. As compared with wild-type cells, UVA induced less PS translocation in gp91phox-deficient cells. No difference, however, was observed in caspase activation and DNA fragmentation after UVA exposure in wild-type and gp91phox-/- cells. These findings suggest that gp91phox plays a limited role in the UVA-induced ROS production, oxidative stress, and therefore the PS translocation, but has no effect on UVA-induced caspase activation and DNA fragmentation during apoptosis.


Assuntos
Apoptose , Queratinócitos/enzimologia , Queratinócitos/efeitos da radiação , Glicoproteínas de Membrana/fisiologia , NADPH Oxidases/fisiologia , Estresse Oxidativo/fisiologia , Raios Ultravioleta , Animais , Transporte Biológico , Caspases/metabolismo , Glutationa/metabolismo , Queratinócitos/efeitos dos fármacos , Glicoproteínas de Membrana/genética , Camundongos , NADPH Oxidase 2 , NADPH Oxidases/genética , Oniocompostos/farmacologia , Oxirredução , Fosfatidilserinas/metabolismo , Espécies Reativas de Oxigênio/metabolismo
11.
Int J Cancer ; 116(1): 20-6, 2005 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-15756686

RESUMO

Inorganic arsenic is a human carcinogen that targets the skin. Carcinogenesis is a multistep process in which acquired apoptotic resistance is a common event and prior work in non-skin cells shows acquired resistance to apoptosis occurs with chronic arsenite exposure. In the present study, when HaCaT cells, an immortalized, non-tumorigenic human keratinocyte cell line, were continuously exposed to low-level inorganic arsenite (as sodium arsenite; 100 nM) for 28 weeks, the cells acquired a generalized resistance to apoptosis. This included resistance to apoptosis induced by acute high concentrations of arsenite, ultraviolet A (UVA) irradiation, and several chemotherapeutic compounds (cisplatin, etoposide and doxorubicin). These arsenite-tolerant (As-TL) cells showed similar levels of UVA-induced reactive oxygen species (ROS) and oxidative DNA damage when compared to passage match control cells. Because cellular apoptosis is dependent on the balance between proapoptotic and survival pathways, the roles of protein kinase B (PKB), a key antiapoptotic molecule, in this acquired apoptotic resistance were investigated. Stimulation of apoptosis markedly decreased nuclear phosphorylated PKB (P-PKB) levels in control cells, but As-TL cells showed greatly increased stability of nuclear P-PKB. Pretreatment of the As-TL cells with LY294002 or Wortmannin, which specifically inhibit PKB phosphorylation, completely blocked apoptotic resistance in As-TL cells, indicating acquired apoptotic resistance is associated with increased stability of nuclear P-PKB. Because arsenic and UV irradiation are co-carcinogenic in mouse skin, resistance to UV-induced apoptosis in As-TL cells may allow UV-damaged cells to escape normal cell population controls and initiate the carcinogenic cascade. The observation that As-TL cells show no lessening of UV-induced genotoxicity supports this possibility.


Assuntos
Apoptose/efeitos dos fármacos , Arsenitos/farmacologia , Queratinócitos/efeitos dos fármacos , Compostos de Sódio/farmacologia , Apoptose/efeitos da radiação , Arsenitos/administração & dosagem , Linhagem Celular , Cocarcinogênese , Dano ao DNA , Humanos , Queratinócitos/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Neoplasias Cutâneas/induzido quimicamente , Compostos de Sódio/administração & dosagem , Fatores de Tempo , Raios Ultravioleta
12.
J Biol Chem ; 279(51): 53867-74, 2004 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-15471881

RESUMO

Exposure to the sun's UV radiation appears to be the most important environmental factor involved in the development of skin cancer. UVA is the major portion of UV radiation in sunlight and is considered to be a human carcinogen. In this study, we have investigated the delayed and sustained activation of ERK MAPK by UVA exposure. In parallel, a delayed Ras activation with a similar time course was observed after UVA exposure. The activated Ras was found to be localized in endomembranes such as the Golgi apparatus instead of plasma membranes. Expression of dominant negative Ras (N17Ras) abolished ERK activation by UVA. The presence of AG1478, an epidermal growth factor (EGF) receptor (EGFR) kinase inhibitor, had no effect on ERK or Ras activation, indicating that EGFR kinase activity is not involved in ERK activation by UVA. In contrast, protein kinase C (PKC) depletion by chronic 12-O-tetradecanoylphorbol-13-acetate treatment nearly abolished UVA-induced ERK and Ras activation. The presence of the Ca(2+)-dependent-PKC inhibitor Go6976 had a similar effect. These findings suggest that ERK activation by UVA is mediated by PKC in a Ras-dependent pathway. In addition, a gradual increase in intracellular calcium level after UVA exposure was detected by flow cytometry. The presence of the PLC inhibitor U73122 or the calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N, N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM) blocked both ERK and Ras activation, suggesting that both PLC and calcium are required for ERK activation. Our findings demonstrated that, different from UVC and UVB, UVA-induced delayed and sustained ERK activation is EGFR kinase activity-independent, but PLC/calcium/PKC-mediated. The delayed and sustained ERK activation provides a survival signal to human HaCaT keratinocytes, which may serve as an important mechanism for cell transformation and potential skin carcinogenesis in vivo caused by UVA exposure.


Assuntos
Ácido Egtázico/análogos & derivados , Queratinócitos/enzimologia , Queratinócitos/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/química , Neoplasias/metabolismo , Raios Ultravioleta , Animais , Apoptose , Western Blotting , Células COS , Cálcio/metabolismo , Carbazóis/farmacologia , Caspase 3 , Caspases/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Sobrevivência Celular , Transformação Celular Neoplásica , Quelantes/farmacologia , Citosol/metabolismo , Relação Dose-Resposta à Radiação , Ácido Egtázico/farmacologia , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Receptores ErbB/antagonistas & inibidores , Estrenos/farmacologia , Citometria de Fluxo , Genes Dominantes , Complexo de Golgi/metabolismo , Humanos , Indóis/farmacologia , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Modelos Biológicos , Plasmídeos/metabolismo , Proteína Quinase C/metabolismo , Pirrolidinonas/farmacologia , Neoplasias Cutâneas/metabolismo , Frações Subcelulares , Acetato de Tetradecanoilforbol/farmacologia , Fatores de Tempo , Transfecção , Proteínas ras/metabolismo
13.
J Invest Dermatol ; 122(2): 533-43, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15009741

RESUMO

Ultraviolet A radiation from sunlight is a major human health concern, as it is not absorbed by the ozone layer and can deeply penetrate into the skin causing skin damage. To study the molecular mechanism involved in the ultraviolet A effect, human HaCaT keratinocytes were exposed to ultraviolet A at doses of 10 J per cm2 and 30 J per cm2. Ultraviolet A irradiation caused dose- and time-dependent apoptotic cell death, as evidenced by DNA fragmentation, flow cytometry, and the activation of caspase-3. To study the genes altered by ultraviolet A at an apoptosis-inducing dose (30 J per cm2), cells were harvested immediately after ultraviolet A treatment (0 h), and 6 h and 24 h after ultraviolet A exposure. Total RNA was extracted for microarray and real-time RT-PCR analysis, and cellular proteins were extracted for western blot analysis. Of the selected critical genes/proteins, the induction of c-Jun, c-myc, and p33ING1, and the repression of epidermal growth factor receptor, inhibitor of apoptosis protein, and survivin pathways, could be involved in ultraviolet-A-induced apoptosis. On the other hand, the late induction of cyclin D1 and cyclin-dependent kinase 4 was indicative of possible cell cycle recovery in surviving cells. Real-time RT-PCR analysis confirmed these results and a majority of the protein levels paralleled their corresponding RNA levels. In addition, ultraviolet A treatment altered the expression of genes involved in signal transduction, RNA processing, structural proteins, and metabolism in a time-dependent manner. This initial microarray analysis could advance our understanding of cellular responses to ultraviolet A exposure, and provide a platform from which to further study ultraviolet-A-induced apoptosis and carcinogenesis.


Assuntos
Apoptose/genética , Apoptose/efeitos da radiação , Perfilação da Expressão Gênica , Queratinócitos/fisiologia , Raios Ultravioleta , Divisão Celular/genética , Divisão Celular/efeitos da radiação , Células Cultivadas , Reparo do DNA , Humanos , Queratinócitos/citologia , Queratinócitos/efeitos da radiação , Biossíntese de Proteínas , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/genética , Transdução de Sinais/efeitos da radiação
14.
J Biol Chem ; 278(43): 42457-65, 2003 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-12930839

RESUMO

Activation of the epidermal growth factor (EGF) receptor by EGF, its ligand, results in receptor internalization and down-regulation, which requires receptor kinase activity, phosphorylation, and ubiquitination. In contrast, we have found here in human HaCaT keratinocytes that exposure to UVA induces EGF receptor internalization and down-regulation without receptor phosphorylation and ubiquitination. The presence of the receptor kinase activity inhibitor AG1478 increased UVA-induced receptor down-regulation, whereas it inhibited EGF-induced receptor down-regulation. These observations demonstrate that, in contrast to EGF, receptor kinase activity is not required for receptor down-regulation by UVA. Concurrent with receptor down-regulation, caspases were activated by UVA exposure. The presence of caspase inhibitors blocked receptor down-regulation in a pattern similar to poly(ADP)-ribose polymerase cleavage. Much more receptor down-regulation was observed after UVA exposure in apoptotic detached cells in which caspase is activated completely. These results indicate that UVA-induced receptor down-regulation is dependent on caspase activation. Similar to UVA, both UVB and UVC induced receptor down-regulation, in which receptor kinase activity is not required, whereas caspase activation is involved. Inhibition of EGF receptor down-regulation increased receptor activation and activation of its downstream survival signaling ERK and AKT after UVA exposure. Preventing the activation of each of these pathways enhanced apoptosis induced by UVA. These findings suggest that EGF receptor down-regulation by UVA may play an important role in the execution of the cell suicide program by attenuating its anti-apoptotic function and thereby preventing cell transformation and tumorigenesis in vivo.


Assuntos
Regulação para Baixo/efeitos da radiação , Receptores ErbB/metabolismo , Queratinócitos/metabolismo , Proteínas Serina-Treonina Quinases , Raios Ultravioleta , Apoptose , Caspase 3 , Caspases/metabolismo , Linhagem Celular , Receptores ErbB/efeitos da radiação , Humanos , Queratinócitos/citologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação/efeitos da radiação , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Ubiquitina/metabolismo
15.
J Biol Chem ; 278(10): 8058-64, 2003 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-12502708

RESUMO

We have investigated the role played by GSH efflux in apoptosis of human HaCaT keratinocytes induced by UVA irradiation. UVA irradiation of HaCaT cells caused a rapid rise in GSH efflux across the intact cell membrane, followed by an increase in apoptosis. GSH efflux was stimulated by glucose and was reduced by the addition of exogenous GSH and intracellular GSH depletion by buthionine sulfoximine, suggesting that GSH transport is active and is influenced by the GSH concentration gradient across the cell membrane. Verapamil and cyclosporin A, blockers of the multidrug resistance-associated protein, decreased UVA-induced GSH efflux. GSH efflux occurred within 2 h of UVA irradiation, suggesting that the stimulation of GSH efflux is due to an increase in the activity of pre-existing multidrug resistance-associated protein transporter carrier. Although inhibition of GSH efflux did not affect caspase activation and DNA fragmentation, it delayed the gradual increase in plasma membrane permeability and reduced phosphatidylserine translocation in HaCaT cells. It is therefore likely that upon UVA irradiation, GSH efflux increased the intracellular oxidative stress without intervention of reactive oxygen species, thus resulting in more phosphatidylserine externalization and membrane rearrangement. These provide targets for macrophage recognition and phagocytosis and thus minimize the potential to invoke inflammation or neoplastic transformation.


Assuntos
Apoptose/efeitos da radiação , Glutationa/metabolismo , Queratinócitos/efeitos da radiação , Raios Ultravioleta , Transporte Biológico , Linhagem Celular Transformada , Citometria de Fluxo , Glutationa/administração & dosagem , Humanos , Queratinócitos/citologia , Queratinócitos/enzimologia , Queratinócitos/metabolismo , L-Lactato Desidrogenase/metabolismo
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