Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
1.
Gynecol Oncol ; 188: 90-96, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38941964

RESUMO

OBJECTIVE: To report the results of a multicenter cohort of preoperative brachytherapy (PBT) for treatment of early-stage cervical cancer (ESCC). METHODS: A retrospective analysis was conducted among five French comprehensive cancer centers on behalf of the SFRO Brachytherapy Group to examine the outcome of patients with ESCC who received PBT between 2001 and 2019 because of adverse prognostic factors (tumor size >2 cm, presence of lymphovascular invasion, adenocarcinoma).Brachytherapy was followed 4-8 weeks later by surgery. Local relapse free, distant metastasis-free survival, disease-free, and overall survival and adverse effects were examined. Uni- and multivariate analyses were conducted looking for oncological prognostic factors. RESULTS: A total of 451 patients were identified, with a mean tumor size of 24.7 mm. Adenocarcinoma accounted for 43.5% of cases, and lympho-vascular space invasion (LVSI) was present in 15.7%. A complete histological response was observed in 69.6%. With a mean follow-up of 75.4 months, DFS, LRFS, and OS rates at five years were 88% [95% CI (84-91), 98% [95% CI (96-99), and 92% [95% CI (87-95)], respectively. At the last follow-up, 8.2% of patients had died, including 31 (6.8%) from cervical cancer. Severe side effects range from 1.1% to 2%. At multivariate analysis, adenocarcinoma histological type, tumor size ≥2 cm, and the presence of residual tumors were prognosticators for DFS and DMFS. CONCLUSION: PBT shows excellent oncological outcomes in this cohort of patients with adverse histoprognostic factors. Favorable survival rates and low complications rates were observed, supporting this strategy in the management of ESCC.

2.
Crit Rev Oncol Hematol ; 197: 104329, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38527594

RESUMO

PURPOSE: We found a need for balancing the application of clinical guidelines and tailored approaches to follow-up of cervical cancer (CC) patients in the lymph node micrometastatic (MICs) setting. This review aimed to determine the current knowledge of management of MIC-positive CC cases. METHODOLOGY: We addressed prognostic and risk of recurrence monitoring impacts associated with MIC+ cases. The electronic databases for literature and relevant articles were analysed. RESULTS: Fifteen studies, (4882 patients), were included in our systematic review. While the results show that MICs significantly worsen prognosis in early CC. A tertiary prevention algorithm for low volume lymph node disease may stratify follow-up according to the burden of nodal disease and provide data that helps improve follow-up performance. CONCLUSION: MICs worsen prognosis and should be managed as suggested by the algorithm. However, this algorithm must be externally validated. The clinical impact of isolated tumor cells (ITC) remains unclear.


Assuntos
Metástase Linfática , Micrometástase de Neoplasia , Neoplasias do Colo do Útero , Feminino , Humanos , Linfonodos/patologia , Micrometástase de Neoplasia/patologia , Recidiva Local de Neoplasia/prevenção & controle , Recidiva Local de Neoplasia/patologia , Prognóstico , Prevenção Terciária/métodos , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/prevenção & controle
3.
Br J Cancer ; 130(7): 1141-1148, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38280968

RESUMO

INTRODUCTION: The MonarchE trial explored the use of abemaciclib, a CDK4/6 inhibitor, as an adjuvant treatment in high-risk early-stage luminal-like breast cancer. The study's inclusion criteria, especially the N2 status, may require revisiting surgical interventions, including invasive axillary lymph node dissection (ALND)-a procedure that current guidelines generally do not recommend. METHODS: We conducted a single-centre, retrospective, observational cohort study on non-metastatic breast cancer patients managed from 2002 to 2011, at the Institut Curie. Data collection involved clinical and histological characteristics plus treatment follow-up. RESULTS: Out of 8715 treated patients, 721 met the inclusion criteria. Overall, 12% (87) were classified as N2 ( ≥ 4 positive lymph nodes), thus eligible for abemaciclib per "node criterion." Tumour size, positive sentinel lymph nodes, and lobular histology showed a significant correlation with N2 status. Approximately 1000 ALNDs would be required to identify 120 N2 cases and prevent four recurrences. CONCLUSION: The MonarchE trial may significantly affect surgical practices due to the need for invasive procedures to identify high-risk patients for adjuvant abemaciclib treatment. The prospect of unnecessary morbidity demands less invasive N2 status determination methods. Surgical decisions must consider patient health and potential treatment benefits.


Assuntos
Aminopiridinas , Benzimidazóis , Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/cirurgia , Neoplasias da Mama/patologia , Biópsia de Linfonodo Sentinela , Estudos Retrospectivos , Reoperação , Metástase Linfática/patologia , Excisão de Linfonodo/efeitos adversos , Axila/patologia , Linfonodos/patologia
4.
EClinicalMedicine ; 65: 102298, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37965434

RESUMO

Background: Gender-based disparities in health-care are common and can affect access to care. We aimed to investigate the impact of gender and socio-environmental indicators on health-care access in oncology in France. Methods: Using the national health insurance system database in France, we identified patients (aged ≥18 years) who were diagnosed with solid invasive cancers between the 1st of January 2018 and the 31st of December 2019. We ensured that only incident cases were identified by excluding patients with an existing cancer diagnosis in 2016 and 2017; skin cancers other than melanoma were also excluded. We extracted 71 socio-environmental variables related to patients' living environment and divided these into eight categories: inaccessibility to public transport, economic deprivation, unemployment, gender-related wage disparities, social isolation, educational barriers, familial hardship, and insecurity. We employed a mixed linear regression model to assess the influence of age, comorbidities, and all eight socio-environmental indices on health-care access, while evaluating the interaction with gender. Health-care access was measured using absolute and relative cancer care expertise indexes. Findings: In total, 594,372 patients were included: 290,658 (49%) women and 303,714 (51%) men. With the exception of unemployment, all socio-environmental indices, age, and comorbidities were inversely correlated with health-care access. However, notable interactions with gender were observed, with a stronger association between socio-environmental factors and health-care access in women than in men. In particular, inaccessibility to public transport (coefficient for absolute cancer care expertise index = -1.10 [-1.22, -0.99], p < 0.0001), familial hardship (-0.64 [-0.72, -0.55], p < 0.0001), social isolation (-0.38 [-0.46, -0.30], p < 0.0001), insecurity (-0.29 [-0.37, -0.21], p < 0.0001), and economic deprivation (-0.13 [-0.19, -0.07], p < 0.0001) had a strong negative impact on health-care access in women. Interpretation: Access to cancer care is determined by a complex interplay of gender and various socio-environmental factors. While gender is a significant component, it operates within the context of multiple socio-environmental influences. Future work should focus on developing targeted interventions to address these multifaceted barriers and promote equitable health-care access for both genders. Funding: None.

5.
Int J Gynecol Cancer ; 33(8): 1181-1184, 2023 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-37460218

RESUMO

The European Society of Gynaecological Oncology (ESGO), the European Society for Radiotherapy and Oncology (ESTRO), and the European Society of Pathology (ESP) jointly published comprehensive evidence-based guidelines on all relevant issues of diagnosis and treatment in endometrial carcinoma in a multidisciplinary setting. In order to improve their implementation, a free downloadable easy-to-use mobile app was developed.Two interactive decision tools were created for (1) helping users to identify the recommended surgical steps, especially in terms of nodal staging approach based on the pre-operatively assumed risk group (tool #1), and (2) to facilitate prognostic risk group allocation and adjuvant treatment decision-making after primary surgery integrating both clinicopathological and molecular markers (if known) (tool #2). Algorithms and readable guidelines were also incorporated into the mobile app on all relevant issues of diagnosis and treatment. The scientific content presented in the app will be updated and modified in the future based on new evidence and user feedback.This article presents the decision tools and two practical examples of using these calculators to illustrate that the ESGO mobile app (available without the necessity of an internet connection) can provide fast and accurate responses to complex clinical questions that require the evaluation of numerous parameters.


Assuntos
Neoplasias do Endométrio , Aplicativos Móveis , Radioterapia (Especialidade) , Feminino , Humanos , Padrão de Cuidado , Neoplasias do Endométrio/diagnóstico , Neoplasias do Endométrio/terapia , Neoplasias do Endométrio/patologia
6.
Cancers (Basel) ; 15(2)2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36672338

RESUMO

Since the validation of the sentinel node technique (SLN) for vulvar cancer 20 years ago, this technique has been introduced in the management of operable cervical cancer and endometrial cancer. For cervical cancer a "one fits all" attitude has mainly been presented. However, this approach, consisting of a frozen section during the operation, can be discussed in some stages. We present and discuss the main option for each stage, as well as some secondary possibilities. For endometrial cancer, SLN is now the technique of choice for the nodal staging of low- and intermediate-risk groups. Some discussion exists for the high-risk group. We also discuss the impacts of using preoperatively the molecular classification of endometrial cancer. Patients with POLE or TP53 mutations could have different nodal staging. The story of SLN in uterine cancers is not finished. We propose a comprehensive algorithm of SLN in early cervical and endometrial cancers. However, several ongoing trials will give us important data in the coming years. They could substantially change these propositions.

7.
Cancers (Basel) ; 14(23)2022 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-36497469

RESUMO

Survival disparities persist in ovarian cancer and may be linked to the environments in which patients live. The main objective of this study was to analyze the global impact of the area of residence of ovarian cancer patients on overall survival. The data were obtained from the Surveillance, Epidemiology and End Results (SEER) database. We included all the patients with epithelial ovarian cancers diagnosed between 2010 and 2016. The areas of residence were analyzed by the hierarchical clustering of the principal components to group similar counties. A multivariable Cox proportional hazards model was then fitted to evaluate the independent effect of each predictor on overall survival. We included a total of 16,806 patients. The clustering algorithm assigned the 607 counties to four clusters, with cluster 1 being the most disadvantaged and cluster 4 having the highest socioeconomic status and best access to care. The area of residence cluster remained a statistically significant independent predictor of overall survival in the multivariable analysis. The patients living in cluster 1 had a risk of death more than 25% higher than that of the patients living in cluster 4. This study highlights the importance of considering the sociodemographic factors within the patient's area of residence when developing a care plan and follow-up.

8.
Front Oncol ; 12: 935628, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36033437

RESUMO

Introduction: Lymph node status is a major prognostic factor in early-stage cervical cancer. Predicting the risk of lymph node metastasis is essential for optimal therapeutic management. The aim of the study was to develop a web-based application to predict the risk of lymph node metastasis in patients with early-stage (IA1 with positive lymph vascular space invasion, IA2 and IB1) cervical cancer. Materials and methods: We performed a secondary analysis of data from two prospective multicenter trials, Senticol 1 and 2 pooled together in the training dataset. The histological risk factors were included in a multivariate logistic regression model in order to determine the most suitable prediction model. An internal validation of the chosen prediction model was then carried out by a cross validation of the 'leave one out cross validation' type. The prediction model was implemented in an interactive online application of the 'Shinyapp' type. Finally, an external validation was performed with a retrospective cohort from L'Hôtel-Dieu de Québec in Canada. Results: Three hundred twenty-one patients participating in Senticol 1 and 2 were included in our training analysis. Among these patients, 280 did not present lymph node invasion (87.2%), 13 presented isolated tumor cells (4%), 11 presented micrometastases (3.4%) and 17 macrometastases (5.3%). Tumor size, presence of lymph-vascular space invasion and stromal invasion were included in the prediction model. The Receiver Operating Characteristic (ROC) Curve from this model had an area under the curve (AUC) of 0.79 (95% CI [0.69- 0.90]). The AUC from the cross validation was 0.65. The external validation on the Canadian cohort confirmed a good discrimination of the model with an AUC of 0.83. Discussion: This is the first study of a prediction score for lymph node involvement in early-stage cervical cancer that includes internal and external validation. The web application is a simple, practical, and modern method of using this prediction score to assist in clinical management.

9.
J Minim Invasive Gynecol ; 29(5): 656-664, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35063645

RESUMO

STUDY OBJECTIVE: To develop a nomogram for predicting the type of ureteral procedure in pelvic deep endometriosis (DE) surgery (1) and to describe the factors and complications associated with the ureteral procedure (2). DESIGN: Retrospective monocentric study of 920 patients who underwent surgery for pelvic DE between June 2009 and March 2020 in the gynecologic surgery department of the Versailles Hospital Center. The main criterion was evaluation of the ureteral procedure, classified as simple (isolation of the ureter) or complex (dissection of the ureter, segmental ureteral resection, or nephroureterectomy). Postoperative complications, including ureteral stenosis and fistula formation, were tabulated. SETTING: Tertiary referral hospital and expert center in endometriosis. PATIENTS: A total of 920 patients with DE. INTERVENTIONS: Ureteral procedure during surgery for DE. MEASUREMENTS AND MAIN RESULTS: In total, 724 patients (79%) underwent a ureteral procedure, of which 307 (33%) were complex, including 17 (1.8%) segmental ureteral resections. In multivariate analysis, the predictive variables for a complex ureteral procedure were age (p = .036), a previous surgery for endometriosis (p <.01), and ureteral dilatation on magnetic resonance imaging (p <.001). The area under the curve for the model predicting a complex ureteral procedure was 0.68 (95% confidence interval, 0.60-0.71). A complex ureteral procedure was associated with a 3.5% rate of ureteral fistula (n = 15). CONCLUSION: Age, a previous surgery for endometriosis, a rectovaginal nodule size ≥30 mm, endometriotic involvement of the rectum or sigmoid, and ureteral dilatation are significantly associated with a complex ureteral procedure. Our results allowed us to build a nomogram that can be used to better inform patients, anticipate the therapeutic strategy, and optimize the modalities of postoperative surveillance.


Assuntos
Endometriose , Laparoscopia , Ureter , Doenças Ureterais , Endometriose/complicações , Endometriose/cirurgia , Feminino , Humanos , Laparoscopia/métodos , Masculino , Nomogramas , Estudos Retrospectivos , Resultado do Tratamento , Ureter/cirurgia , Doenças Ureterais/cirurgia
10.
Gynecol Oncol ; 164(2): 446-454, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34949436

RESUMO

OBJECTIVE: In order to define the clinical significance of low-volume metastasis, a comprehensive meta-analysis of published data and individual data obtained from articles mentioning micrometastases (MIC) and isolated tumor cells (ITC) in cervical cancer was performed, with a follow up of at least 3 years. METHODS: We performed a systematic literature review and meta-analysis, following Cochrane's review methods guide and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The primary outcome was the disease-free survival (DFS), and the secondary outcome was the overall survival (OS). The hazard ratio (HR) was taken as the measure of the association between the low-volume metastases (MIC+ITC and MIC alone) and DFS or OS; it quantified the hazard of an event in the MIC (+/- ITC) group compared to the hazard in node-negative (N0) patients. A random-effect meta-analysis model using the inverse variance method was selected for pooling. Forest plots were used to display the HRs and risk differences within individual trials and overall. RESULTS: Eleven articles were finally retained for the meta-analysis. In the analysis of DFS in patients with low-volume metastasis (MIC + ITC), the HR was increased to 2.60 (1.55-4.34) in the case of low-volume metastasis vs. N0. The presence of MICs had a negative prognostic impact, with an HR of 4.10 (2.71-6.20) compared to N0. Moreover, this impact was worse than that of MIC pooled with ITCs. Concerning OS, the meta-analysis shows an HR of 5.65 (2.81-11.39) in the case of low-volume metastases vs. N0. The presence of MICs alone had a negative effect, with an HR of 6.94 (2.56-18.81). CONCLUSIONS: In conclusion, the presence of MIC seems to be associated with a negative impact on both the DFS and OS and should be treated as MAC.


Assuntos
Adenocarcinoma/patologia , Carcinoma de Células Escamosas/patologia , Micrometástase de Neoplasia/patologia , Linfonodo Sentinela/patologia , Neoplasias do Colo do Útero/patologia , Adenocarcinoma/terapia , Carcinoma de Células Escamosas/terapia , Intervalo Livre de Doença , Feminino , Humanos , Linfonodos/patologia , Metástase Linfática , Estadiamento de Neoplasias , Biópsia de Linfonodo Sentinela , Taxa de Sobrevida , Carga Tumoral , Neoplasias do Colo do Útero/terapia
11.
JCO Clin Cancer Inform ; 5: 1127-1133, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34767435

RESUMO

PURPOSE: The treatment of breast cancer, the leading cause of cancer and cancer mortality among women worldwide, is mainly on the basis of surgery. In this study, we describe the use of a medical image visualization tool on the basis of virtual reality (VR), entitled DIVA, in the context of breast cancer tumor localization among surgeons. The aim of this study was to evaluate the speed and accuracy of surgeons using DIVA for medical image analysis of breast magnetic resonance image (MRI) scans relative to standard image slice-based visualization tools. MATERIALS AND METHODS: In our study, residents and practicing surgeons used two breast MRI reading modalities: the common slice-based radiology interface and the DIVA system in its VR mode. Metrics measured were compared in relation to postoperative anatomical-pathologic reports. RESULTS: Eighteen breast surgeons from the Institut Curie performed all the analysis presented. The MRI analysis time was significantly lower with the DIVA system than with the slice-based visualization for residents, practitioners, and subsequently the entire group (P < .001). The accuracy of determination of which breast contained the lesion significantly increased with DIVA for residents (P = .003) and practitioners (P = .04). There was little difference between the DIVA and slice-based visualization for the determination of the number of lesions. The accuracy of quadrant determination was significantly improved by DIVA for practicing surgeons (P = .01) but not significantly for residents (P = .49). CONCLUSION: This study indicates that the VR visualization of medical images systematically improves surgeons' analysis of preoperative breast MRI scans across several different metrics irrespective of surgeon seniority.


Assuntos
Neoplasias da Mama , Cirurgiões , Realidade Virtual , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/cirurgia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino
12.
PLoS One ; 16(10): e0258783, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34665839

RESUMO

OBJECTIVE: The aim of this study was to develop a new diagnostic tool to predict lymph node metastasis (LNM) in patients with advanced epithelial ovarian cancer undergoing primary cytoreductive surgery. MATERIALS AND METHOD: The FRANCOGYN group's multicenter retrospective ovarian cancer cohort furnished the patient population on which we developed a logistic regression model. The prediction model equation enabled us to create LNM risk groups with simple lymphadenectomy decision rules associated with a user-friendly free interactive web application called shinyLNM. RESULTS: 277 patients from the FRANCOGYN cohort were included; 115 with no LNM and 162 with LNM. Three variables were independently and significantly (p<0.05) associated with LNM in multivariate analysis: pelvic and/or para-aortic LNM on CT and/or PET/CT (p<0.00), initial PCI ≥ 10 and/or diaphragmatic carcinosis (p = 0.02), and initial CA125 ≥ 500 (p = 0.02). The ROC-AUC of this prediction model after leave-one-out cross-validation was 0.72. There was no difference between the predicted and the observed probabilities of LNM (p = 0.09). Specificity for the group at high risk of LNM was 83.5%, the LR+ was 2.73, and the observed probability of LNM was 79.3%; sensitivity for the group at low-risk of LNM was 92.0%, the LR- was 0.24, and the observed probability of LNM was 25.0%. CONCLUSION: This new tool may prove useful for improving surgical planning and provide useful information for patients.


Assuntos
Carcinoma Epitelial do Ovário/cirurgia , Tomada de Decisão Clínica/métodos , Excisão de Linfonodo/métodos , Metástase Linfática/diagnóstico , Neoplasias Ovarianas/cirurgia , Idoso , Carcinoma Epitelial do Ovário/patologia , Procedimentos Cirúrgicos de Citorredução , Feminino , França , Humanos , Internet , Modelos Logísticos , Metástase Linfática/patologia , Pessoa de Meia-Idade , Neoplasias Ovarianas/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Estudos Retrospectivos
13.
J Clin Med ; 10(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806443

RESUMO

To determine if the time-to-chemotherapy (TTC) after primary macroscopic complete cytoreductive surgery (CRS) influences recurrence-free survival (RFS) and overall survival (OS) in patients with epithelial ovarian cancer (EOC). We conducted an observational multicenter retrospective cohort analysis of women with EOC treated from September 2006 to November 2016 in nine institutions in France (FRANCOGYN research group) with maintained EOC databases. We included women with EOC (all FIGO stages) who underwent primary complete macroscopic CRS prior to platinum-based adjuvant chemotherapy. Two hundred thirty-three patients were included: 73 (31.3%) in the early-stage group (ESG) (FIGO I-II), and 160 (68.7%) in the advanced-stage group (ASG) (FIGO III-IV). Median TTC was 43 days (36-56). The median OS was 77.2 months (65.9-106.6). OS was lower in the ASG when TTC exceeded 8 weeks (70.5 vs. 59.3 months, p = 0.04). No impact on OS was found when TTC was below or above 6 weeks (78.5 and 66.8 months, respectively, p = 0.25). In the whole population, TTC had no impact on RFS or OS. None of the factors studied were associated with an increase in TTC. Chemotherapy should be initiated as soon as possible after CRS. A TTC greater than 8 weeks is associated with poorer OS in patients with advanced stage EOC.

14.
Eur J Histochem ; 65(1)2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33728864

RESUMO

Therapeutic strategies for epithelial ovarian cancers are evolving with the advent of immunotherapy, such as PD-L1 inhibitors, with encouraging results. However, little data are available on PDL-1 expression in ovarian cancers. Thus, we set out to determine the PD-L1 expression according to histological subtype. We evaluated the expression of two PD-L1 clones - QR1 and E1L3N - with two scores, one based on the percentage of labeled tumor cells (tumor proportion score, TPS) and the other on labeled immune cells (combined proportion score, CPS) in a consecutive retrospective series of 232 ovarian cancers. PD-L1 expression was more frequent in high grade serous carcinoma (27.5% with E1L3N clone and 41.5% with QR1 clone), grade 3 endometrioid carcinoma (25% with E1L3N clone and 50% with QR1 clone), and clear-cell carcinomas (27.3% with E1L3N clone and 29.6% with QR1 clone) than other histological subtypes with CPS score. Using the CPS score, 17% of cases were labeled with E1L3N vs 28% with QR1. Using the TPS score, 14% of cases were positive to E1L3N vs 17% for QR1. For TPS and CPS, respectively, 77% and 78% of the QR1 cases were concordant with E1L3N for the thresholds of 1%. Overall and progression-free survival between PD-L1 positive and PD-L1 negative patients were not different across all histological types, and each subtype in particular for serous carcinomas expressing PD-L1. Expression of PD-L1 is relatively uncommon in epithelium ovarian tumors. When positive, usually <10% of tumor cells are labeled. QR1 clone and CPS appear the best tools to evaluate PD-L1 expression.


Assuntos
Anticorpos Monoclonais/imunologia , Antígeno B7-H1/metabolismo , Neoplasias Ovarianas/metabolismo , Animais , Antígeno B7-H1/imunologia , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Neoplasias Ovarianas/classificação , Neoplasias Ovarianas/patologia , Coelhos
15.
PLoS Comput Biol ; 16(1): e1007600, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31917825

RESUMO

Designed enzymes are of fundamental and technological interest. Experimental directed evolution still has significant limitations, and computational approaches are a complementary route. A designed enzyme should satisfy multiple criteria: stability, substrate binding, transition state binding. Such multi-objective design is computationally challenging. Two recent studies used adaptive importance sampling Monte Carlo to redesign proteins for ligand binding. By first flattening the energy landscape of the apo protein, they obtained positive design for the bound state and negative design for the unbound. We have now extended the method to design an enzyme for specific transition state binding, i.e., for its catalytic power. We considered methionyl-tRNA synthetase (MetRS), which attaches methionine (Met) to its cognate tRNA, establishing codon identity. Previously, MetRS and other synthetases have been redesigned by experimental directed evolution to accept noncanonical amino acids as substrates, leading to genetic code expansion. Here, we have redesigned MetRS computationally to bind several ligands: the Met analog azidonorleucine, methionyl-adenylate (MetAMP), and the activated ligands that form the transition state for MetAMP production. Enzyme mutants known to have azidonorleucine activity were recovered by the design calculations, and 17 mutants predicted to bind MetAMP were characterized experimentally and all found to be active. Mutants predicted to have low activation free energies for MetAMP production were found to be active and the predicted reaction rates agreed well with the experimental values. We suggest the present method should become the paradigm for computational enzyme design.


Assuntos
Enzimas , Método de Monte Carlo , Ligação Proteica/genética , Engenharia de Proteínas/métodos , Especificidade por Substrato/genética , Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/química , Monofosfato de Adenosina/metabolismo , Azidas/química , Azidas/metabolismo , Sítios de Ligação/genética , Catálise , Enzimas/química , Enzimas/genética , Enzimas/metabolismo , Metionina/análogos & derivados , Metionina/química , Metionina/metabolismo , Metionina tRNA Ligase/química , Metionina tRNA Ligase/genética , Metionina tRNA Ligase/metabolismo , Mutação/genética , Norleucina/análogos & derivados , Norleucina/química , Norleucina/metabolismo
16.
Int J Cardiol ; 266: 206-212, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29887449

RESUMO

BACKGROUND: Iron deficiency (ID), with or without anemia, is frequent in heart failure patients, and iron supplementation improves patient condition. However, the link between ID (independently of anemia) and cardiac function is poorly understood, but could be explained by an impaired mitochondrial metabolism. Our aim was to explore this hypothesis in a mouse model. METHODS AND RESULTS: We developed a mouse model of ID without anemia, using a blood withdrawal followed by 3-weeks low iron diet. ID was confirmed by low spleen, liver and heart iron contents and the repression of HAMP gene coding for hepcidin. ID was corrected by a single ferric carboxymaltose (FCM) injection (ID + FCM mice). Hemoglobin levels were similar in ID, ID + FCM and control mice. ID mice had impaired physical performances and left ventricular function (echocardiography). Mitochondrial complex I activity of cardiomyocytes was significantly decreased in ID mice, but not complexes II, III and IV activities. ID + FCM mice had improved physical performance, cardiac function and complex I activity compared to ID mice. Using BN-PAGE, we did not observe complex I disassembly, but a reduced quantity of the whole enzyme complex I in ID mice, that was restored in ID + FCM mice. CONCLUSIONS: ID, independently of anemia, is responsible for a decreased left ventricular function, through a reduction in mitochondrial complex I activity, probably secondary to a decrease in complex I quantity. These abnormalities are reversed after iron treatment, and may explain, at least in part, the benefit of iron supplementation in heart failure patients with ID.


Assuntos
Modelos Animais de Doenças , Complexo I de Transporte de Elétrons/metabolismo , Deficiências de Ferro , Mitocôndrias/metabolismo , Resistência Física/fisiologia , Disfunção Ventricular Esquerda/metabolismo , Anemia Ferropriva , Animais , Complexo I de Transporte de Elétrons/deficiência , Ferro/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/fisiopatologia , Baço/metabolismo , Disfunção Ventricular Esquerda/fisiopatologia
17.
Artigo em Inglês | MEDLINE | ID: mdl-26056980

RESUMO

In this study, experimental far infrared measurements of L-serine, L-threonine, L-cysteine, and L-methionine are presented showing the spectra for the 1.0-13.0 pH range. In parallel, solid state DFT calculations were performed on the amino acid zwitterions in the crystalline form. We focused on the lowest frequency far infrared normal modes, which required the most precision and convergence of the calculations. Analysis of the computational results, which included the potential energy distribution of the vibrational modes, permitted a detailed and almost complete assignment of the experimental spectrum. In addition to characteristic signals of the two main acid-base couples, CO2H/CO2(-) and NH3(+)/NH2, specific side chain contributions for these amino acids, including CCO and CCS vibrational modes were analyzed. This study is in line with the growing application of FIR measurements to biomolecules.


Assuntos
Cisteína/química , Metionina/química , Prótons , Serina/química , Treonina/química , Modelos Moleculares , Conformação Molecular , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Vibração , Água/química
18.
Crit Care ; 18(6): 678, 2014 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-25673336

RESUMO

Iron as an element is a double-edged sword, essential for living but also potentially toxic through the generation of oxidative stress. The recent study by Chen and colleagues in Critical Care reminds us of this elegantly. In a mouse model of acute lung injury, they showed that silencing hepcidin (the master regulator of iron metabolism) locally in airway epithelial cells aggravates lung injury by increasing the release of iron from alveolar macrophages, which in turn enhances pulmonary bacterial growth and reduces the macrophages' killing properties. This work underscores that hepcidin acts not only systematically (as a hormone) but also locally for iron metabolism regulation. This opens areas of research for sepsis treatment but also for iron deficiency or anaemia treatment, since the local and systemic iron regulation appear to be independent.


Assuntos
Lesão Pulmonar Aguda/microbiologia , Líquido da Lavagem Broncoalveolar/microbiologia , Hepcidinas/fisiologia , Ferro/metabolismo , Sepse/microbiologia , Animais , Masculino
19.
J Comput Chem ; 34(28): 2472-84, 2013 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-24037756

RESUMO

We describe an automated procedure for protein design, implemented in a flexible software package, called Proteus. System setup and calculation of an energy matrix are done with the XPLOR modeling program and its sophisticated command language, supporting several force fields and solvent models. A second program provides algorithms to search sequence space. It allows a decomposition of the system into groups, which can be combined in different ways in the energy function, for both positive and negative design. The whole procedure can be controlled by editing 2-4 scripts. Two applications consider the tyrosyl-tRNA synthetase enzyme and its successful redesign to bind both O-methyl-tyrosine and D-tyrosine. For the latter, we present Monte Carlo simulations where the D-tyrosine concentration is gradually increased, displacing L-tyrosine from the binding pocket and yielding the binding free energy difference, in good agreement with experiment. Complete redesign of the Crk SH3 domain is presented. The top 10000 sequences are all assigned to the correct fold by the SUPERFAMILY library of Hidden Markov Models. Finally, we report the acid/base behavior of the SNase protein. Sidechain protonation is treated as a form of mutation; it is then straightforward to perform constant-pH Monte Carlo simulations, which yield good agreement with experiment. Overall, the software can be used for a wide range of application, producing not only native-like sequences but also thermodynamic properties with errors that appear comparable to other current software packages.


Assuntos
Biologia Computacional , Proteínas/química , Software , Algoritmos , Concentração de Íons de Hidrogênio , Modelos Moleculares , Simulação de Dinâmica Molecular , Método de Monte Carlo , Desdobramento de Proteína , Proteínas Proto-Oncogênicas c-crk/química , Tirosina/análogos & derivados , Tirosina/química , Tirosina/metabolismo , Tirosina-tRNA Ligase/química , Tirosina-tRNA Ligase/metabolismo , Domínios de Homologia de src
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA