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1.
Artigo em Inglês | MEDLINE | ID: mdl-38453781

RESUMO

PURPOSE: Previous studies have reported the benefit of dual HER2-targeting combined to neoadjuvant chemotherapy in HER2-amplified breast cancer (HER2 + BC). Moreover, besides the cardiac toxicity following their association to Trastuzumab, anthracyclines chemotherapy may not profit all patients. The NeoTOP study was designed to evaluate the complementary action of Trastuzumab and Pertuzumab, and the relevance of an anthracycline-based regimen according to TOP2A amplification status. METHODS: Open-label, multicentre, phase II study. Eligible patients were aged ≥ 18 with untreated, operable, histologically confirmed HER2 + BC. After centralized review of TOP2A status, TOP2A-amplified (TOP2A+) patients received FEC100 for 3 cycles then 3 cycles of Trastuzumab (8 mg/kg then 6 mg/kg), Pertuzumab (840 mg/kg then 420 mg/kg), and Docetaxel (75mg/m2 then 100mg/m2). TOP2A-not amplified (TOP2A-) patients received 6 cycles of Docetaxel (75mg/m2) and Carboplatin (target AUC 6 mg/ml/min) plus Trastuzumab and Pertuzumab. Primary endpoint was pathological Complete Response (pCR) using Chevallier's classification. Secondary endpoints included pCR (Sataloff), Progression-Free Survival (PFS), Overall Survival (OS), and toxicity. RESULTS: Out of 74 patients, 41 and 33 were allocated to the TOP2A + and TOP2A- groups respectively. pCR rates (Chevallier) were 74.4% (95%CI: 58.9-85.4) vs. 71.9% (95%CI: 54.6-84.4) in the TOP2A + vs. TOP2A- groups. pCR rates (Sataloff), 5-year PFS and OS were 70.6% (95%CI: 53.8-83.2) vs. 61.5% (95%CI: 42.5-77.6), 82.4% (95%CI: 62.2-93.6) vs. 100% (95%CI: 74.1-100), and 90% (95%CI: 69.8-98.3) vs. 100% (95%CI: 74.1-100). Toxicity profile was consistent with previous reports. CONCLUSION: Our results showed high pCR rates with Trastuzumab and Pertuzumab associated to chemotherapy. They were similar in TOP2A + and TOP2A- groups and the current role of neoadjuvant anthracycline-based chemotherapy remains questioned. TRIAL REGISTRATION NUMBER: NCT02339532 (registered on 14/12/14).

2.
JAMA Psychiatry ; 80(11): 1101-1109, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37556150

RESUMO

Importance: During the COVID-19 pandemic, health care workers (HCWs) reported a significant decline in their mental health. One potential health behavior intervention that has been shown to be effective for improving mental health is exercise, which may be facilitated by taking advantage of mobile application (app) technologies. Objective: To determine the extent to which a 12-week app-based exercise intervention can reduce depressive symptoms, burnout, and absenteeism in HCWs, compared with a wait list control condition. Design, Setting, and Participants: A 2-group randomized clinical trial was conducted, with participants screened from April 6 to July 4, 2022. Participants were recruited from an urban health care organization in British Columbia, Canada. Participants completed measures before randomization and every 2 weeks thereafter. Interventions: Exercise condition participants were asked to complete four 20-minute sessions per week using a suite of body weight interval training, yoga, barre, and running apps. Wait-listed control participants received the apps at the end of the trial. Main Outcomes and Measures: The primary outcome consisted of the between-group difference in depressive symptoms measured with the 10-item Center for Epidemiological Studies Depression Scale. The secondary outcomes corresponded to 3 subfacets of burnout (cynicism, emotional exhaustion, and professional efficacy) and absenteeism. Intention-to-treat analyses were completed with multilevel structural equation modeling, and Feingold effect sizes (ES) were estimated every 2 weeks. Results: A total of 288 participants (mean [SD] age, 41.0 [10.8] years; 246 [85.4%] women) were randomized to either exercise (n = 142) or wait list control (n = 146) conditions. Results revealed that ESs for depressive symptoms were in the small to medium range by trial's end (week 12, -0.41 [95% CI, -0.69 to -0.13]). Significant and consistent treatment effects were revealed for 2 facets of burnout, namely cynicism (week 12 ES, -0.33 [95% CI, -0.53 to -0.13]) and emotional exhaustion (week 12 ES, -0.39 [95% CI, -0.64 to -0.14]), as well as absenteeism (r = 0.15 [95% CI, 0.03-0.26]). Adherence to the 80 minutes per week of exercise decreased from 78 (54.9%) to 33 (23.2%) participants between weeks 2 and 12. Conclusions and Relevance: Although exercise was able to reduce depressive symptoms among HCWs, adherence was low toward the end of the trial. Optimizing adherence to exercise programming represents an important challenge to help maintain improvements in mental health among HCWs. Trial Registration: ClinicalTrials.gov Identifier: NCT05271006.


Assuntos
Absenteísmo , Depressão , Adulto , Feminino , Humanos , Masculino , Colúmbia Britânica , Esgotamento Psicológico , Depressão/terapia , Pandemias , Pessoa de Meia-Idade
3.
Eur J Cancer ; 166: 300-308, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35337692

RESUMO

BACKGROUND: Besides their development as additional adjuvant treatments, CDK4/6 inhibitors combined with endocrine therapy could represent less toxic alternatives to chemotherapy in postmenopausal women with high-risk oestrogen receptor-positive, HER2-negative breast cancer currently a candidate for chemotherapy. The multicentre, international, randomised phase 2 NEOPAL trial showed that the letrozole-palbociclib combination led to clinical and pathological responses equivalent to sequential anthracycline-taxanes chemotherapy. Secondary objectives included survival outcomes. METHODS: Secondary end-points of NEOPAL included progression-free survival (PFS) and invasive-disease free survival (iDFS) in the intent-to-treat population. Exploratory end-points were overall survival (OS) and breast cancer specific survival (BCSS) in the intent-to-treat population, as well as iDFS, OS and BCSS according to the administration of chemotherapy. RESULTS: Hundred and six patients were randomised. Pathological complete response rates were 3.8% and 5.9%. Twenty-three of the 53 patients in the letrozole-palbociclib arm received postoperative adjuvant chemotherapy. At a median follow-up of 40.4 months [0-56.6], 11 progressions have been observed, of which three were in the letrozole-palbociclib and 8 in the control arm. PFS (HR = 1.01; [95%CI 0.36-2.90], p = 0.98) and iDFS (HR = 0.83; [95%CI 0.31-2.23], p = 0.71) did not differ between both arms. The 40 months PFS rate was 86.7% [95%CI 78.0-96.4] and 89.9% [95%CI 81.8-98.7] in letrozole-palbociclib and control arms, respectively. Outcomes of patients who did not receive chemotherapy were not statistically different from those who received it. CONCLUSIONS: NEOPAL suggests that a neoadjuvant letrozole-palbociclib strategy may allow sparing chemotherapy in some patients with luminal breast cancer while allowing good long-term outcomes. Larger confirmatory studies are needed.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias da Mama , Terapia Neoadjuvante , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Feminino , Humanos , Letrozol , Terapia Neoadjuvante/efeitos adversos , Piperazinas , Piridinas , Receptor ErbB-2 , Receptores de Estrogênio , Análise de Sobrevida
4.
Cancers (Basel) ; 12(6)2020 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-32486421

RESUMO

BACKGROUND: Predictive biomarkers of response to chemotherapy plus antiangiogenic for metastatic colorectal cancer (mCRC) are lacking. The objective of this study was to test the prognostic role of splenomegaly on baseline CT scan. METHODS: This study is a sub-study of PRODIGE-9 study, which included 488 mCRC patients treated by 5-fluorouracil, leucovorin and irinotecan (FOLFIRI) and bevacizumab in first line. The association between splenic volume, and PFS and OS was evaluated by univariate and multivariable Cox analyses. The relation between circulating monocytic Myeloid derived suppressor cells (mMDSC) and splenomegaly was also determined. RESULTS: Baseline splenic volume > 180 mL was associated with poor PFS (median PFS = 9.2 versus 11.1 months; log-rank p = 0.0125), but was not statistically associated with OS (median OS = 22.6 versus 28.5 months; log-rank p = 0.1643). The increase in splenic volume at 3 months had no impact on PFS (HR 0.928; log-rank p = 0.56) or on OS (HR 0.843; log-rank p = 0.21). Baseline splenic volume was positively correlated with the level of baseline circulating mMDSC (r = 0.48, p-value = 0.031). CONCLUSION: Baseline splenomegaly is a prognostic biomarker in patients with mCRC treated with FOLFIRI and bevacizumab, and a surrogate marker of MDSC accumulation.

5.
Gut ; 69(4): 681-690, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31780575

RESUMO

OBJECTIVE: Diagnostic tests, such as Immunoscore, predict prognosis in patients with colon cancer. However, additional prognostic markers could be detected on pathological slides using artificial intelligence tools. DESIGN: We have developed a software to detect colon tumour, healthy mucosa, stroma and immune cells on CD3 and CD8 stained slides. The lymphocyte density and surface area were quantified automatically in the tumour core (TC) and invasive margin (IM). Using a LASSO algorithm, DGMate (DiGital tuMor pArameTErs), we detected digital parameters within the tumour cells related to patient outcomes. RESULTS: Within the dataset of 1018 patients, we observed that a poorer relapse-free survival (RFS) was associated with high IM stromal area (HR 5.65; 95% CI 2.34 to 13.67; p<0.0001) and high DGMate (HR 2.72; 95% CI 1.92 to 3.85; p<0.001). Higher CD3+ TC, CD3+ IM and CD8+ TC densities were significantly associated with a longer RFS. Analysis of variance showed that CD3+ TC yielded a similar prognostic value to the classical CD3/CD8 Immunoscore (p=0.44). A combination of the IM stromal area, DGMate and CD3, designated 'DGMuneS', outperformed Immunoscore when used in estimating patients' prognosis (C-index=0.601 vs 0.578, p=0.04) and was independently associated with patient outcomes following Cox multivariate analysis. A predictive nomogram based on DGMuneS and clinical variables identified a group of patients with less than 10% relapse risk and another group with a 50% relapse risk. CONCLUSION: These findings suggest that artificial intelligence can potentially improve patient care by assisting pathologists in better defining stage III colon cancer patients' prognosis.


Assuntos
Adenocarcinoma/patologia , Inteligência Artificial , Neoplasias do Colo/patologia , Interpretação de Imagem Assistida por Computador , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/mortalidade , Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/mortalidade , Intervalo Livre de Doença , Humanos , Linfócitos do Interstício Tumoral , Invasividade Neoplásica , Estadiamento de Neoplasias , Prognóstico
7.
Oncologist ; 19(12): 1231-40, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25361624

RESUMO

Abiraterone acetate, a prodrug of the CYP17A1 inhibitor abiraterone that blocks androgen biosynthesis, is approved for treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) in combination with prednisone or prednisolone 5 mg twice daily. This review evaluates the basis for the effects of prednisone on mineralocorticoid-related adverse events that arise because of CYP17A1 inhibition with abiraterone. Coadministration with the recommended dose of glucocorticoid compensates for abiraterone-induced reductions in serum cortisol and blocks the compensatory increase in adrenocorticotropic hormone seen with abiraterone. Consequently, 5 mg prednisone twice daily serves as a glucocorticoid replacement therapy when coadministered with abiraterone acetate, analogous to use of glucocorticoid replacement therapy for certain endocrine disorders. We searched PubMed to identify safety concerns regarding glucocorticoid use, placing a focus on longitudinal studies in autoimmune and inflammatory diseases and cancer. In general, glucocorticoid-related adverse events, including bone loss, immunosuppression, hyperglycemia, mood and cognitive alterations, and myopathy, appear dose related and tend to occur at doses and/or treatment durations greater than the low dose of glucocorticoid approved in combination with abiraterone acetate for the treatment of mCRPC. Although glucocorticoids are often used to manage tumor-related symptoms or to prevent treatment-related toxicity, available evidence suggests that prednisone and dexamethasone might also offer modest therapeutic benefit in mCRPC. Given recent improvements in survival achieved for mCRPC with novel agents in combination with prednisone, the risks of these recommended glucocorticoid doses must be balanced with the benefits shown for these regimens.


Assuntos
Androstenos/uso terapêutico , Antineoplásicos Hormonais/uso terapêutico , Prednisona/uso terapêutico , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Progressão da Doença , Humanos , Masculino , Metástase Neoplásica , Neoplasias de Próstata Resistentes à Castração/patologia
8.
J Clin Oncol ; 32(31): 3520-6, 2014 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-25287828

RESUMO

PURPOSE: To compare epirubicin, cisplatin, and capecitabine (ECX) with fluorouracil, leucovorin, and irinotecan (FOLFIRI) as first-line treatments in patients with advanced gastric or esophagogastric junction (EGJ) adenocarcinoma. PATIENTS AND METHODS: This open, randomized, phase III study was carried out in 71 centers. Patients with locally advanced or metastatic gastric or EGJ cancer were randomly assigned to receive either ECX as first-line treatment (ECX arm) or FOLFIRI (FOLFIRI arm). Second-line treatment was predefined (FOLFIRI for the ECX arm and ECX for the FOLFIRI arm). The primary criterion was time-to-treatment failure (TTF) of the first-line therapy. Secondary criteria were progression-free survival (PFS), overall survival (OS), toxicity, and quality of life. RESULTS: In all, 416 patients were included (median age, 61.4 years; 74% male). After a median follow-up of 31 months, median TTF was significantly longer with FOLFIRI than with ECX (5.1 v 4.2 months; P = .008). There was no significant difference between the two groups in median PFS (5.3 v 5.8 months; P = .96), median OS (9.5 v 9.7 months; P = .95), or response rate (39.2% v 37.8%). First-line FOLFIRI was better tolerated (overall rate of grade 3 to 4 toxicity, 69% v 84%; P < .001; hematologic adverse events [AEs], 38% v 64.5%; P < .001; nonhematologic AEs: 53% v 53.5%; P = .81). CONCLUSION: FOLFIRI as first-line treatment for advanced gastric and EGJ cancer demonstrated significantly better TTF than did ECX. Other outcome results indicate that FOLFIRI is an acceptable first-line regimen in this setting and should be explored as a backbone regimen for targeted agents.


Assuntos
Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Junção Esofagogástrica/patologia , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Camptotecina/administração & dosagem , Camptotecina/análogos & derivados , Capecitabina , Cisplatino/administração & dosagem , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Epirubicina/administração & dosagem , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/análogos & derivados , Seguimentos , França , Humanos , Irinotecano , Leucovorina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Qualidade de Vida , Análise de Sobrevida , Resultado do Tratamento
9.
Eur J Cancer ; 50(6): 1076-83, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24433843

RESUMO

BACKGROUND: For resectable gastric cancer, both postoperative chemoradiotherapy and perioperative chemotherapy demonstrate high-level evidence for improved survival in Western populations. To evaluate the feasibility of pre- or postoperative chemoradiotherapy, we proposed two multicentre phase II studies. PATIENTS AND METHODS: Patients with localised, histologically confirmed gastric cancer and Eastern Cooperative Oncology Group (ECOG) performance status <2 judged suitable for curative resection were eligible. Eligible patients were assigned to either preoperative chemoradiotherapy followed by surgical resection or surgical resection followed by chemoradiotherapy depending on each centre. Chemoradiotherapy regimen included four courses of FOLFIRI (5 Fluorouracil, Leucovorin, Irinotecan) regimen then Concurrent fluorouracil at 200 mg/m2/d by continuous infusion 5 days each week. A dose of 50 Gy in 25 fractions in the preoperative study, or 45 Gy in 25 fractions in the postoperative study, was delivered. The primary end-point for both studies was the proportion of patients, who completed the therapeutic sequence. RESULTS: Between September 2007 and January 2010, 63 patients were included in both studies. The postoperative study was stopped for futility at the first step. In the preoperative study, 31 patients (73.8%, confidence interval (CI) 95%: 65.8-90.1%) received complete therapeutic sequence. Serum albumin and dietary restriction evaluated by QLQ-STO22 (Quality of Life-Stomach module) score were significantly linked with chemoradiotherapy feasibility in univariate analysis with respectively Odds-ratio (OR) 1.16 [CI 95%: 1.01-1.33] and 0.17 [0.03-0.89], p=0.04. Median overall survival time was 26.4 months in the preoperative study. CONCLUSION: Feasibility of chemoradiotherapy was not achieved for these studies: 73.8% (CI 95%: 65.8-90.1) and 42.9% (CI 95%: 21.8-66%) in preoperative and postoperative settings respectively.


Assuntos
Adenocarcinoma/terapia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Fracionamento da Dose de Radiação , Neoplasias Gástricas/terapia , Adenocarcinoma/cirurgia , Adulto , Idoso , Camptotecina/administração & dosagem , Camptotecina/análogos & derivados , Quimiorradioterapia , Estudos de Viabilidade , Feminino , Fluoruracila/administração & dosagem , Humanos , Irinotecano , Leucovorina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Período Pós-Operatório , Período Pré-Operatório , Estômago/efeitos dos fármacos , Estômago/efeitos da radiação , Estômago/cirurgia , Neoplasias Gástricas/cirurgia , Análise de Sobrevida , Resultado do Tratamento
10.
Dev Dyn ; 236(6): 1663-76, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17477386

RESUMO

DNA methylation is an epigenetic mechanism involved in gene regulation and implicated in the functioning of the nervous system. The de novo DNA methyltransferase Dnmt3a is expressed in neurons, but its specific role has not been clarified. Dnmt3a is activated around embryonic day 10.5 in mouse neuronal precursor cells and remains active in postmitotic neurons in the adult. We assessed the role of neuronal Dnmt3a by conditional gene targeting. Mice lacking functional Dnmt3a in the nervous system were born healthy, but degenerated in adulthood and died prematurely. Mutant mice were hypoactive, walked abnormally, and underperformed on tests of neuromuscular function and motor coordination. Loss of Dnmt3a also led to fewer motor neurons in the hypoglossal nucleus and more fragmented endplates in neuromuscular junctions of the diaphragm muscle. Our results implicate a role for Dnmt3a in the neuromuscular control of motor movement.


Assuntos
DNA (Citosina-5-)-Metiltransferases/deficiência , DNA (Citosina-5-)-Metiltransferases/metabolismo , Longevidade/fisiologia , Sistema Nervoso/metabolismo , Sistema Nervoso/patologia , Doenças Neuromusculares/metabolismo , Doenças Neuromusculares/patologia , Animais , Comportamento Animal , Peso Corporal , Proliferação de Células , DNA (Citosina-5-)-Metiltransferases/genética , DNA Metiltransferase 3A , Diafragma/metabolismo , Diafragma/patologia , Deleção de Genes , Integrases/genética , Integrases/metabolismo , Proteínas de Filamentos Intermediários/genética , Proteínas de Filamentos Intermediários/metabolismo , Metilação , Camundongos , Camundongos Knockout , Mutação/genética , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Nestina , Doenças Neuromusculares/genética , Especificidade de Órgãos , Fatores de Tempo
11.
Mol Cell Biol ; 26(8): 2976-83, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16581773

RESUMO

Aberrant gene silencing accompanied by DNA methylation is associated with neoplastic progression in many tumors that also show global loss of DNA methylation. Using conditional inactivation of de novo methyltransferase Dnmt3b in Apc(Min/+) mice, we demonstrate that the loss of Dnmt3b has no impact on microadenoma formation, which is considered the earliest stage of intestinal tumor formation. Nevertheless, we observed a significant decrease in the formation of macroscopic colonic adenomas. Interestingly, many large adenomas showed regions with Dnmt3b inactivation, indicating that Dnmt3b is required for initial outgrowth of macroscopic adenomas but is not required for their maintenance. These results support a role for Dnmt3b in the transition stage between microadenoma formation and macroscopic colonic tumor growth and further suggest that Dnmt3b, and by extension de novo methylation, is not required for maintaining tumor growth after this transition stage has occurred.


Assuntos
DNA (Citosina-5-)-Metiltransferases/metabolismo , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Inativação Gênica , Neoplasias Intestinais/genética , Adenoma/genética , Adenoma/patologia , Alelos , Animais , Western Blotting , DNA (Citosina-5-)-Metiltransferases/genética , Metilação de DNA , DNA de Neoplasias/metabolismo , Imuno-Histoquímica , Neoplasias Intestinais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Biológicos , DNA Metiltransferase 3B
12.
Bull Cancer ; 93(1): E1-6, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16455499

RESUMO

METHODS: We evaluated the Epitax combination (epirubicin 60 mg/m2 and docetaxel 75 mg/m2, every 3 weeks) in advanced gastric cancer (AGC) as second-line treatment after fluorouracil and platinum in 50 patients, then as first-line treatment in 36 patients. We report here the results of these two phase II studies. RESULTS: In the second-line treatment, the response rate (RR) was 15.5%. Grade 3-4 neutropenia was observed in 68% (febrile neutropenia in 40%, one treatment-related death). Median time to progression (TTP) and overall survival (OS) were 2.4 and 5.0 months, respectively. In the first-line treatment, the RR was 19.4%. With prophylactic granulocyte colony-stimulating factor, grade 3-4 neutropenia was reported in 38.9%. Then 22 patients received a second-line and 11 patients a third-line treatment. Median TTP and OS were 4.5 and 12 months, respectively. CONCLUSION: Epitax showed moderate activity in AGC. RR in both trials suggests a non-cross resistance with fluorouracil/platinum combination. The 12-month OS in the first-line treatment could be partly explained by early evaluation and active non-cross resistant second-line therapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Gástricas/tratamento farmacológico , Adulto , Idoso , Progressão da Doença , Docetaxel , Epirubicina/administração & dosagem , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/tratamento farmacológico , Neutropenia/induzido quimicamente , Neoplasias Gástricas/patologia , Análise de Sobrevida , Taxoides/administração & dosagem , Resultado do Tratamento
13.
Antioxid Redox Signal ; 5(1): 103-13, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12626122

RESUMO

The stress-activated protein kinases SAPK/JNK and p38/mHOG are activated by diverse classes of stress stimuli, many of which induce redox perturbations. We studied the effects of reactive quinones on stress signaling pathways. Menadione (2-methyl-1,4-naphthoquinone), which undergoes both one- and two-electron reduction, completely inhibited SAPK activity at high concentrations while activating SAPK at lower concentrations. Menadione activated p38/mHOG dose responsively. 2,3-Dimethyl-1,4-naphthoquinone (DMNQ), which preferentially undergoes two-electron reduction, had similar effects. In contrast, 1,4-naphthoquinone, which preferentially undergoes one-electron reduction, inhibited SAPK at high concentrations, but failed to activate SAPK at any concentration tested. In addition, this quinone activated p38 only at lower concentrations; high concentrations inhibited p38 activity. These activity profiles correlated with the activation state of the upstream kinase, indicating that the effects were mediated by an upstream step in the kinase pathway. The quinone reductase inhibitor dicoumarol blocked activation of SAPK by menadione and DMNQ, suggesting that two-electron reduction is important. Finally, addition of increasing amounts of hydrogen peroxide mimicked the effects of menadione and DMNQ, suggesting that hydrogen peroxide may be the relevant mediator. Differential activation of stress kinases by reactive quinones demonstrates that the cellular redox environment independently modulates these pathways.


Assuntos
Proteínas Quinases Ativadas por Mitógeno/metabolismo , Quinonas/metabolismo , Animais , Antifibrinolíticos/farmacologia , Dicumarol/farmacologia , Relação Dose-Resposta a Droga , Elétrons , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/farmacologia , Camundongos , Células NIH 3T3 , Naftoquinonas/farmacologia , Osmose , Oxirredução , Isoformas de Proteínas , Desacopladores/farmacologia , Vitamina K 3/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno
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