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INTRODUCTION: Nipple-sparing mastectomy (NSM) offers improved, patient-centered outcomes with demonstrated oncologic safety ( Ann Surg Oncol 2020;27:344-351). Indications for NSM continue to expand to patients outside of the traditional eligibility criteria, including those with prior breast-conserving therapy (BCT) with radiotherapy. Currently, limited data exist evaluating both short- and long-term outcomes in patients proceeding to NSM after prior BCT. METHODS: All patients undergoing bilateral NSM in a single institution from 2002 through 2017 with history of prior BCT were included in the final cohort, without exclusions. A retrospective chart review was performed to identify patient demographics, operative details, and complications. Outcomes assessed included early complications (<30 days from NSM), late complications (>30 days), rates of prosthetic failure, unplanned reoperations, and reconstructive failures, as well as oncologic safety. Student t , χ 2 , and Fisher exact tests were used to analyze outcomes of paired (BCT vs non-BCT) breasts within each patient. RESULTS: A total of 17 patients undergoing 34 NSMs were included. Each had a history of BCT and either ipsilateral breast recurrence (64.7%), risk-reducing NSM (23.5%), or a new contralateral primary cancer (11.8%). The cohort had a mean age of 51.1 years. With regard to acute complications (ischemia, infection, nipple-areolar complex or flap ischemia or necrosis, and wound dehiscence), there was no significant difference noted between breasts with prior BCT versus no prior BCT overall (41.2% vs 35.3%, respectively; P = 0.724). Complications occurring after 30 days postoperatively (capsular contracture, contour abnormality, animation deformity, bottoming out, rotation, and rippling) in prior BCT breasts versus no prior BCT had no significant differences overall (58.8% vs 41.2% respectively; P = 0.303). The mean follow-up was 5.5 years, during which no patients had a reported locoregional or distant recurrence in either breast. CONCLUSIONS: No significant differences in early or late complications were identified between breasts in patients undergoing bilateral NSM with a history of unilateral BCT and XRT. In the 5.5 years of follow-up, there were no recurrences, lending support to NSM for management of recurrent disease in addition to National Comprehensive Cancer Network-recommended total mastectomy. We propose that NSM should not be contraindicated in patients exposed to radiation with BCT.
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Neoplasias da Mama , Mamoplastia , Humanos , Pessoa de Meia-Idade , Feminino , Mastectomia , Estudos Retrospectivos , Mamilos/cirurgia , Neoplasias da Mama/radioterapia , Neoplasias da Mama/cirurgia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/cirurgia , IsquemiaRESUMO
Opioid-free anesthesia (OFA) is being implemented in breast surgery due to increased awareness of adverse effects and the national opioid crisis. The objective of this study was to examine the effect of OFA on postoperative pain and postoperative nausea and vomiting (PONV) in mastectomy patients. A single-institution matched-cohort study was conducted from 2014 to 2017 on 48 women undergoing mastectomy, with the majority also undergoing immediate prosthetic-based reconstruction. Patients received either conventional anesthesia (CA) or a novel OFA regimen. Primary outcomes included postoperative pain scores, opioid use, and need for antiemetics that were evaluated both in the PACU and on the hospital floors. No significant differences were found in PACU opioid or antiemetic use between OFA and CA. Pain scores in PACU and on POD0 were not significantly different. There was a significant but modest decrease on POD1 in OFA patients (3.9 vs. 5.1, P = .046). Additionally, patients with higher intraoperative opioid regimens experienced significantly increased PONV (P = .023). This study demonstrated the efficacy of OFA in controlling postoperative pain and nausea compared to a traditional opioid-based regimen. Regardless of intraoperative opioids, patients experienced similar postoperative opioid requirements and PONV with decreased pain scores. Thus, OFA is feasible in mastectomy patients and should be further evaluated in select patients.
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Anestesia , Neoplasias da Mama , Analgésicos Opioides/efeitos adversos , Neoplasias da Mama/cirurgia , Estudos de Coortes , Feminino , Humanos , Mastectomia , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/etiologia , Estudos RetrospectivosRESUMO
BACKGROUND: Ten percent of new breast cancer diagnoses occur in premenopausal women, and oncologic therapies may compromise fertility. Thus, fertility preservation discussions (FPDs) and referral to fertility specialists are imperative prior to initiation of therapy. A previous retrospective chart review showed 45% FPD rates at our institution. The aim of this study is to investigate physician perspectives and limitations regarding FPD. METHODS: An electronic survey was distributed to 30 surgical, medical, and radiation oncologists across ten regional hospitals. Questions addressed provider demographics, and barriers to and facilitators of FPD. RESULTS: The survey response rate was 63.3%. Only 31.6% of physicians reported "always" documenting FPD. Respondents opined that the physician prescribing systemic therapy was the most appropriate person to provide FPD. Patient age, treatment with chemotherapy, and patient desire for FPD were more likely to increase FPD (p < 0.0001, p < 0.05, and p < 0.0001, respectively). The majority of physicians (84.2%) expressed intent to increase FPD rates. CONCLUSIONS: Fertility preservation is an integral aspect of breast cancer care, requiring thorough discussion and clear documentation. This study identified that physicians believe the medical oncologist is the most appropriate person to have FPDs with patients and that empowering patients to bring up fertility concerns may improve rates of FPDs. Education of physicians and patients about fertility preservation techniques is likely to improve FPDs.
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Neoplasias da Mama/psicologia , Comunicação , Preservação da Fertilidade/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Oncologia/estatística & dados numéricos , Médicos/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Neoplasias da Mama/tratamento farmacológico , Feminino , Humanos , Educação de Pacientes como Assunto , Médicos/psicologia , Pré-Menopausa , Encaminhamento e ConsultaRESUMO
Breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) is a rare lymphoma that has been associated with textured breast implants. Most cases present as a delayed (>1 year) seroma, which can be aspirated for diagnosis. Fewer patients present with masses or skin signs. Surgical resection is the cornerstone of treatment for this form of lymphoma. For advanced disease, treatment is multidisciplinary and incorporates adjuvant chemotherapy, radiation therapy, and potentially, the immunotherapeutic agent brentuximab vedotin, an anti-CD30 antibody-drug conjugate. However, relapse rates are high among patients with peripheral ALCL. We present the case of a 39-year-old woman who developed BIA-ALCL 13 years after augmentation with silicone, textured implants and had a complete pathologic response to neoadjuvant cyclophosphamide, doxorubicin (hydroxydaunomycin), vincristine (Oncovin), etoposide, prednisolone (CHOEP) at time of bilateral removal of implants and capsules. CHOEP is a long-standing regimen for treatment of peripheral ALCL and is a suggested regimen for treatment of BIA-ALCL. This case report is the first to demonstrate the use of neoadjuvant chemotherapy in the treatment of BIA-ALCL and suggests a role for its use in advanced disease.
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BACKGROUND: Cervical ectopic pregnancy can lead to catastrophic hemorrhage, and may be managed conservatively with intra-amniotic methotrexate (MTX), systemic MTX, or both; surgical evacuation with or without balloon tamponade; and uterine artery embolization. However, some patients require hysterectomy, which has traditionally been performed abdominally. CASE: A 39-year-old parous woman was diagnosed with cervical ectopic pregnancy at an estimated 7 1/7 weeks of gestation. Her ß-hCG level remained at 29,433 milli-international units/mL, and the gestational sac persisted on ultrasonography after first intra-amniotic then multidose systemic MTX treatment. After a review of other fertility-sparing procedures, she chose definitive treatment with hysterectomy because she did not desire future childbearing. She underwent a successful vaginal hysterectomy, a novel approach for this condition. CONCLUSION: Vaginal hysterectomy can be performed successfully for treatment of cervical ectopic pregnancy in patients who have completed childbearing and for whom conservative treatment has failed.
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Colo do Útero , Histerectomia Vaginal , Gravidez Ectópica/cirurgia , Abortivos não Esteroides/uso terapêutico , Adulto , Feminino , Humanos , Metotrexato/uso terapêutico , Gravidez , Gravidez Ectópica/diagnóstico por imagemRESUMO
Resistance to DNA-damaging chemotherapy is a barrier to effective treatment that appears to be augmented by p53 functional deficiency in many cancers. In p53-deficient cells in which the G1-S checkpoint is compromised, cell viability after DNA damage relies upon intact intra-S and G2-M checkpoints mediated by the ATR (ataxia telangiectasia and Rad3 related) and Chk1 kinases. Thus, a logical rationale to sensitize p53-deficient cancers to DNA-damaging chemotherapy is through the use of ATP-competitive inhibitors of ATR or Chk1. To discover small molecules that may act on uncharacterized components of the ATR pathway, we performed a phenotype-based screen of 9,195 compounds for their ability to inhibit hydroxyurea-induced phosphorylation of Ser345 on Chk1, known to be a critical ATR substrate. This effort led to the identification of four small-molecule compounds, three of which were derived from known bioactive library (anthothecol, dihydrocelastryl, and erysolin) and one of which was a novel synthetic compound termed MARPIN. These compounds all inhibited ATR-selective phosphorylation and sensitized p53-deficient cancer cells to DNA-damaging agents in vitro and in vivo. Notably, these compounds did not inhibit ATR catalytic activity in vitro, unlike typical ATP-competitive inhibitors, but acted in a mechanistically distinct manner to disable ATR-Chk1 function. Our results highlight a set of novel molecular probes to further elucidate druggable mechanisms to improve cancer therapeutic responses produced by DNA-damaging drugs.
Assuntos
Neoplasias/genética , Proteínas Quinases/biossíntese , Proteína Supressora de Tumor p53/genética , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/biossíntese , Catálise/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quinase 1 do Ponto de Checagem , Dano ao DNA/efeitos dos fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular , Células HeLa , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Proteínas Quinases/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/administração & dosagemRESUMO
OBJECTIVES: Intratumoral CD8+ lymphocytes (IT-CD8s) have shown promise as a prognostic indicator for Merkel cell carcinoma (MCC). We tested whether IT-CD8s predict survival among a population-based MCC cohort. METHODS: One hundred thirty-seven MCC cases that had not previously been analyzed for IT-CD8s were studied. RESULTS: Three-year MCC-specific survival rates were 56%, 72%, and 100% for patients with absent (n = 46), low (n = 85), and moderate or strong (n = 6) IT-CD8s, respectively. Increased IT-CD8s were associated with improved MCC-specific survival in a multivariate competing risk-regression analysis including stage, age, and sex (hazard ratio [HR] = 0.5; 95% confidence interval [CI] = 0.3-0.9). Although a similar trend was observed for overall survival, statistical significance was not reached (HR = 0.8; 95% CI = 0.6-1.0), likely because of the high rate of non-MCC deaths among older patients. CONCLUSIONS: This study of prospectively captured MCC cases supports the concept that cellular immunity is important in MCC outcome and that CD8+ lymphocyte infiltration adds prognostic information to conventional staging.
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Linfócitos T CD8-Positivos/imunologia , Carcinoma de Célula de Merkel/imunologia , Carcinoma de Célula de Merkel/patologia , Neoplasias Cutâneas/mortalidade , Neoplasias Cutâneas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Célula de Merkel/mortalidade , Estudos de Coortes , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estadiamento de Neoplasias , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Neoplasias Cutâneas/imunologia , Taxa de SobrevidaRESUMO
Merkel cell carcinoma (MCC) is an aggressive, polyomavirus-associated skin cancer. Robust cellular immune responses are associated with excellent outcomes in patients with MCC, but these responses are typically absent. We determined the prevalence and reversibility of major histocompatibility complex class I (MHC-I) downregulation in MCC, a potentially reversible immune-evasion mechanism. Cell-surface MHC-I expression was assessed on five MCC cell lines using flow cytometry as well as immunohistochemistry on tissue microarrays representing 114 patients. Three additional patients were included who had received intralesional IFN treatment and had evaluable specimens before and after treatment. mRNA expression analysis of antigen presentation pathway genes from 35 MCC tumors was used to examine the mechanisms of downregulation. Of note, 84% of MCCs (total n = 114) showed reduced MHC-I expression as compared with surrounding tissues, and 51% had poor or undetectable MHC-I expression. Expression of MHC-I was lower in polyomavirus-positive MCCs than in polyomavirus-negative MCCs (P < 0.01). The MHC-I downregulation mechanism was multifactorial and did not depend solely on HLA gene expression. Treatment of MCC cell lines with ionizing radiation, etoposide, or IFN resulted in MHC-I upregulation, with IFNs strongly upregulating MHC-I expression in vitro, and in 3 of 3 patients treated with intralesional IFNs. MCC tumors may be amenable to immunotherapy, but downregulation of MHC-I is frequently present in these tumors, particularly those that are positive for polyomavirus. This downregulation is reversible with any of several clinically available treatments that may thus promote the effectiveness of immune-stimulating therapies for MCC.
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Carcinoma de Célula de Merkel/imunologia , Antígenos de Histocompatibilidade Classe I/biossíntese , Neoplasias Cutâneas/imunologia , Evasão Tumoral/imunologia , Antineoplásicos/uso terapêutico , Carcinoma de Célula de Merkel/tratamento farmacológico , Linhagem Celular Tumoral , Regulação para Baixo , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Interferon beta/uso terapêutico , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias Cutâneas/tratamento farmacológico , Análise Serial de TecidosRESUMO
OBJECTIVES: To determine the clinical utility of p63 expression, which has been identified in several cohorts as a predictor of poorer prognosis in Merkel cell carcinoma (MCC). METHODS: Immunohistochemistry was used to determine p63 expression on MCC tumors from 128 patients. RESULTS: Of the patients, 33% had detectable p63 expression. p63 Positivity was associated with an increased risk of death from MCC (hazard ratio, 2.05; P = .02) in a multivariate Cox regression model considering stage at presentation, age at diagnosis, and sex. Although p63 expression correlated with diminished survival in this largest cohort reported thus far, the effect was weaker than that observed in prior studies. Indeed, within a given stage, p63 status did not predict survival in a clinically or statistically significant manner. CONCLUSIONS: It remains unclear whether this test should be integrated into routine MCC patient management.
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Biomarcadores Tumorais/análise , Carcinoma de Célula de Merkel/mortalidade , Proteínas de Membrana/biossíntese , Neoplasias Cutâneas/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Célula de Merkel/metabolismo , Carcinoma de Célula de Merkel/patologia , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Proteínas de Membrana/análise , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologiaRESUMO
BACKGROUND: Merkel cell carcinoma is a polyomavirus-associated cancer that is strongly linked with T lymphocyte immune suppression in epidemiologic studies. CD8+ T cell infiltration into MCC tumors (intratumoral) has recently been shown to be strongly predictive of improved survival. In contrast, the presence of CD8+ T cells at the border of the tumor (peritumoral) had no independent prognostic value. Spontaneous regression has been reported for MCC approximately one thousand times more often than would be expected given the frequency of this cancer. Many of these events began shortly after biopsy, and in some cases lymphocytic infiltration was described. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether CD8+ lymphocyte infiltration in MCC tumors is commonly altered by biopsy.33 MCC patients who had microscopic confirmation of MCC on both an initial biopsy and a re-excision specimen were included in this study. Intratumoral and peritumoral CD8 lymphocyte infiltration was quantitated using immunohistochemistry and compared using the paired t-test in biopsy versus re-excision samples. There was a trend toward increased CD8 infiltration after biopsy in a peritumoral ('stalled') pattern (p = 0.08), however, biopsy was not associated with a significant increase in CD8 T cells in the clinically more important intratumoral location (p = 0.58). CONCLUSIONS/SIGNIFICANCE: The initial diagnostic biopsy for MCC does not commonly alter intratumoral CD8+ T cell infiltration, suggesting it does not directly induce immunologic recognition of this cancer. Because CD8 infiltration is typically stable after biopsy, this parameter may be useful to assess the efficacy of future immune therapies for this virus-associated, immunogenic, often-lethal cancer.
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Linfócitos T CD8-Positivos/patologia , Carcinoma de Célula de Merkel/patologia , Regressão Neoplásica Espontânea , Neoplasias Cutâneas/patologia , Idoso , Idoso de 80 Anos ou mais , Biópsia , Carcinoma de Célula de Merkel/diagnóstico , Carcinoma de Célula de Merkel/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/imunologiaRESUMO
Multiple human epidemiologic studies link caffeinated (but not decaffeinated) beverage intake with significant decreases in several types of cancer, including highly prevalent UV-associated skin carcinomas. The mechanism by which caffeine protects against skin cancer is unknown. Ataxia telangiectasia and Rad3-related (ATR) is a replication checkpoint kinase activated by DNA stresses and is one of several targets of caffeine. Suppression of ATR, or its downstream target checkpoint kinase 1 (Chk1), selectively sensitizes DNA-damaged and malignant cells to apoptosis. Agents that target this pathway are currently in clinical trials. Conversely, inhibition of other DNA damage response pathways, such as ataxia telangiectasia mutated (ATM) and BRCA1, promotes cancer. To determine the effect of replication checkpoint inhibition on carcinogenesis, we generated transgenic mice with diminished ATR function in skin and crossed them into a UV-sensitive background, Xpc(-/-). Unlike caffeine, this genetic approach was selective and had no effect on ATM activation. These transgenic mice were viable and showed no histological abnormalities in skin. Primary keratinocytes from these mice had diminished UV-induced Chk1 phosphorylation and twofold augmentation of apoptosis after UV exposure (P = 0.006). With chronic UV treatment, transgenic mice remained tumor-free for significantly longer (P = 0.003) and had 69% fewer tumors at the end of observation of the full cohort (P = 0.019), compared with littermate controls with the same genetic background. This study suggests that inhibition of replication checkpoint function can suppress skin carcinogenesis and supports ATR inhibition as the relevant mechanism for the protective effect of caffeinated beverage intake in human epidemiologic studies.
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Proteínas de Ciclo Celular/antagonistas & inibidores , Queratinócitos/efeitos da radiação , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Neoplasias Cutâneas/prevenção & controle , Raios Ultravioleta/efeitos adversos , Animais , Apoptose , Proteínas Mutadas de Ataxia Telangiectasia , Cafeína/farmacologia , Proteínas de Ciclo Celular/genética , Quinase 1 do Ponto de Checagem , Queratinócitos/citologia , Camundongos , Camundongos Transgênicos , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/patologiaRESUMO
PURPOSE: Merkel cell carcinoma (MCC) is a polyomavirus-associated skin cancer that is frequently lethal and lacks established prognostic biomarkers. This study sought to identify biomarkers that improve prognostic accuracy and provide insight into MCC biology. PATIENTS AND METHODS: Gene expression profiles of 35 MCC tumors were clustered based on prognosis. The cluster of genes overexpressed in good-prognosis tumors was tested for biologic process enrichment. Relevant mRNA expression differences were confirmed by quantitative polymerase chain reaction and immunohistochemistry. An independent set of 146 nonoverlapping MCC tumors (median follow-up, 25 months among 116 living patients) was employed for biomarker validation. Univariate and multivariate Cox regression analyses were performed. RESULTS: Immune response gene signatures were prominent in patients with good prognoses. In particular, genes associated with cytotoxic CD8+ lymphocytes were overexpressed in tumors from patients with favorable prognoses. In the independent validation set, cases with robust intratumoral CD8+ lymphocyte infiltration had improved outcomes (100% MCC-specific survival, n = 26) compared with instances characterized by sparse infiltration (60% survival, n = 120). Only stage and intratumoral CD8 infiltration (but not age, sex, or CD8+ lymphocytes localized to the tumor-stroma interface) were significant in both univariate and multivariate Cox regression analyses. Notably, traditional histologic identification of tumor-infiltrating lymphocytes was not a significant independent predictor of survival. CONCLUSION: Intratumoral CD8+ lymphocyte infiltration can be readily assessed on paraffin-embedded tissue, is independently associated with improved MCC-specific survival, and therefore, may provide prognostic information that enhances established MCC staging protocols.
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Linfócitos T CD8-Positivos/imunologia , Carcinoma de Célula de Merkel/diagnóstico , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Linfócitos do Interstício Tumoral/imunologia , Neoplasias Cutâneas/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Áustria , Linfócitos T CD8-Positivos/patologia , Carcinoma de Célula de Merkel/genética , Carcinoma de Célula de Merkel/imunologia , Carcinoma de Célula de Merkel/mortalidade , Carcinoma de Célula de Merkel/patologia , Análise por Conglomerados , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Linfócitos do Interstício Tumoral/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Inclusão em Parafina , Prognóstico , Modelos de Riscos Proporcionais , Queensland , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Medição de Risco , Fatores de Risco , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/mortalidade , Neoplasias Cutâneas/patologia , Taxa de Sobrevida , Fatores de Tempo , WashingtonRESUMO
BACKGROUND: Serum- and glucocorticoid-inducible kinase-1 (SGK1) increases CFTR Cl currents in Xenopus oocytes by an unknown mechanism. Because SGK increases the plasma membrane expression of other ion channels, the goal of this paper was to test the hypothesis that SGK1 stimulates CFTR Cl currents by increasing the number of CFTR Cl channels in the plasma membrane. METHODS: CFTR Cl currents were measured in Xenopus oocytes by the two-electrode voltage clamp technique, and CFTR in the plasma membrane was determined by laser scanning confocal microscopy. RESULTS: wt-SGK1 stimulated CFTR Cl currents by 42% and increased the amount of CFTR in the plasma membrane by 35%. A kinase-dead SGK mutant (K127N) had a dominant-negative effect on CFTR, reducing CFTR Cl currents by 38%. In addition, deletion of the C-terminal PDZ-interacting motif (SGK1-DeltaSFL) increased CFTR Cl currents by 108%. Thus, SGK1-DeltaSFL was more effective than wt-SGK1 in stimulating CFTR Cl currents. Neither wt-SGK nor the K127N mutant had any effect on Cl currents in oocytes when expressed alone in the absence of CFTR. CONCLUSION: SGK1 stimulates CFTR Cl currents in Xenopus oocytes by increasing the number of channels in the plasma membrane. Moreover, the effect of SGK may be mediated by protein-protein interactions involving the PDZ interacting motif.
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Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Proteínas Imediatamente Precoces/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , 1-Metil-3-Isobutilxantina/farmacologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Membrana Celular/metabolismo , Feminino , Fundulidae/genética , Humanos , Proteínas Imediatamente Precoces/genética , Técnicas In Vitro , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , XenopusRESUMO
Killifish are euryhaline teleosts that adapt to rapid changes in the salinity of the seawater. It is generally accepted that acclimation to seawater is mediated by cortisol activation of the glucocorticoid receptor (GR), which stimulates CFTR mRNA expression and CFTR-mediated Cl- secretion by the gill. Because there is no direct evidence in killifish that the GR stimulates CFTR gene expression, quantitative PCR studies were conducted to test the hypothesis that cortisol activation of GR upregulates CFTR mRNA expression and that this response is required for acclimation to seawater. Inhibition of the GR by RU-486 prevented killifish from acclimating to increased salinity and blocked the increase in CFTR mRNA. In contrast, inhibition of the mineralocorticoid receptor by spironolactone had no effect on acclimation to seawater. Thus acclimation to increased salinity in killifish requires signaling via the GR and includes an increase in CFTR gene expression. Because arsenic, a toxic metalloid that naturally occurs in the aquatic environment, has been shown to disrupt GR transcriptional regulation in avian and mammalian systems, studies were also conducted to determine whether arsenic disrupts cortisol-mediated activation of CFTR gene expression in this in vivo fish model and thereby blocks the ability of killifish to acclimate to increased salinity. Arsenic prevented acclimation to seawater and decreased CFTR protein abundance. However, arsenic did not disrupt the GR-induced increase in CFTR mRNA. Thus arsenic blocks acclimation to seawater in killifish by a mechanism that does not disrupt GR-mediated induction of CFTR gene expression.
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Aclimatação/fisiologia , Arsênio/toxicidade , Fundulidae/fisiologia , Receptores de Glucocorticoides/fisiologia , Água do Mar , Aclimatação/efeitos dos fármacos , Animais , Arsênio/farmacocinética , Western Blotting , Cloretos/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/biossíntese , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Brânquias/metabolismo , Homeostase/efeitos dos fármacos , Homeostase/fisiologia , Antagonistas de Hormônios/farmacologia , Hidrocortisona/farmacologia , Espectrometria de Massas , Mifepristona/farmacologia , Antagonistas de Receptores de Mineralocorticoides/farmacologia , Receptores de Glucocorticoides/antagonistas & inibidores , Receptores de Mineralocorticoides/efeitos dos fármacos , Receptores de Mineralocorticoides/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Simportadores de Cloreto de Sódio-Potássio/biossíntese , Simportadores de Cloreto de Sódio-Potássio/genética , ATPase Trocadora de Sódio-Potássio/biossíntese , ATPase Trocadora de Sódio-Potássio/genética , Membro 2 da Família 12 de Carreador de Soluto , Espironolactona/farmacologia , Distribuição TecidualRESUMO
Killifish are euryhaline teleosts that normally experience rapid changes in the salinity of the swim water. Acclimation to seawater is mediated by cortisol, which by activating glucocorticoid receptors, upregulates CFTR mediated Cl- secretion in the gill and operculum. Arsenic, a toxic metalloid that naturally occurs in the aquatic environment, has been shown to disrupt glucocorticoid hormone-mediated regulation of genes. Because little is known about the effects of environmentally relevant levels of arsenic on ion channels and salt homeostasis, studies were conducted to examine the effects of arsenic on the ability of killifish to acclimate to increased salinity. Arsenic in the swim water or administered by intraperitoneal injection prevented acclimation. To determine if arsenic blocked acclimation by inhibiting CFTR mediated Cl- secretion (Isc), opercular membranes were isolated and mounted in Ussing chambers and the effects of arsenic on Isc were measured. Arsenic (24 hr exposure) reduced Isc in opercular membranes isolated from salt water acclimated killifish. In addition, arsenic acutely (5-10 minutes) and reversibly inhibited Isc with an IC50 = 4.1 microM (305 ppb) when applied to the apical (seawater) side of the operculum, but not when added to the basolateral side of the operculum. Arsenic (4 microM for 60 minutes) also reduced mitochondrial respiration. Thus, environmentally relevant levels of arsenic block acclimation to seawater in killifish by reversibly inhibiting CFTR-mediated Cl- secretion by the opercular membrane, in part by inhibiting mitochondrial respiration.