RESUMO
OBJECTIVE: To evaluate the impact of transoral robotic surgery (TORS) and non-robotic transoral endoscopic surgery on margin positivity, rates of adjuvant therapy and survival in early stage oropharyngeal squamous cell carcinoma. STUDY DESIGN: Retrospective cohort review. SUBJECTS AND METHODS: The National Cancer Database was queried to form a cohort of patients with T1-T2 N0-N1 MO oropharyngeal squamous cell carcinoma who underwent TORS or Non-robotic endoscopic surgery from 2010 to 2015. Demographics, disease characteristics and rate of positive margin and adjuvant therapy were summarized. A binary logistic regression and a cox-proportional hazard model were performed to evaluate patient demographic, disease, and treatment factors that could predict margin positivity and survival respectively. RESULTS: 1026 patients received TORS treatment while 734 patients received non-robotic endoscopic primary surgery. Non-robotic surgery was more likely to have residual tumor (31.6 % of all cases) compared to TORS procedures (13.6 % of TORS cases); p < .0001. Non-robotic surgery more frequently had non-evaluable margins at 8.1 % compared to only 1.4 % of TORS cases (p < .0001). Non-robotic cases had a significantly higher proportion of patients receiving adjuvant radiotherapy and systemic therapy compared to TORS (66.4 % vs 51.3 % for radiotherapy; p < .0001 and 33.4 % vs 22.2 % for chemotherapy; p < .0001). There was no difference in mortality between the two modalities (non-robotic vs TORS, HR 1.357, 95 % CI 0.937-1.967). CONCLUSION: TORS and non-robotic surgery may have a similar impact on survival in early-stage OPSCC, but non-robotic surgery was found to have a higher likelihood of positive margins and a higher rate of adjuvant chemoradiation therapy.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Orofaríngeas , Procedimentos Cirúrgicos Robóticos , Humanos , Procedimentos Cirúrgicos Robóticos/métodos , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Estudos Retrospectivos , Carcinoma de Células Escamosas/patologia , Estadiamento de Neoplasias , Neoplasias Orofaríngeas/patologia , Quimiorradioterapia Adjuvante , Neoplasias de Cabeça e Pescoço/patologiaRESUMO
OBJECTIVE: To evaluate the role of social and geographic factors on the likelihood of receiving transoral robotic surgery (TORS) or non-robotic transoral endoscopic surgery treatment in early stage oropharyngeal squamous cell carcinoma (OPSCC). MATERIALS AND METHODS: The National Cancer Database was queried to form a cohort of patients with T1-T2 N0-N1 M0 OPSCC (AJCC v.7) who underwent treatment from 2010 to 2016. Demographics, tumor characteristics, treatment type, social, and geographic factors were all collected. Univariate analysis and multivariate logistic regression were then performed. RESULTS: Among 9267 identified patients, 1774 (19.1%) received transoral robotic surgery (TORS), 1191 (12.9%) received transoral endoscopic surgery, and 6302 (68%) received radiation therapy. We found that lower cancer stage, lower comorbidity burden and HPV- positive status predicted a statistically significant increased likelihood of receiving surgery. Patients who reside in suburban or small urban areas (>1 million population), were low-to- middle income, or rely on Medicaid were less likely to receive surgery. Patients that reside in Medicaid-expansion states were more likely to receive TORS (p > .0001). Patients that reside in states that expanded Medicaid January 2014 and after were more likely to receive non-robotic transoral endoscopic surgery (p > .0001). CONCLUSIONS: Poorer baseline health, lower socioeconomic status and residence in small urban areas may act as barriers to accessing minimally invasive transoral surgery while residence in a Medicaid-expansion state may improve access. Barriers to accessing robotic surgery may be greater than accessing non-robotic surgery.
Assuntos
Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Cirurgia Endoscópica por Orifício Natural/estatística & dados numéricos , Neoplasias Orofaríngeas/cirurgia , Procedimentos Cirúrgicos Robóticos/estatística & dados numéricos , Carcinoma de Células Escamosas de Cabeça e Pescoço/cirurgia , Idoso , Bases de Dados Factuais , Feminino , Geografia , Humanos , Masculino , Pessoa de Meia-Idade , Cirurgia Endoscópica por Orifício Natural/métodos , Estadiamento de Neoplasias , Neoplasias Orofaríngeas/patologia , Estudos Retrospectivos , Procedimentos Cirúrgicos Robóticos/métodos , Fatores Socioeconômicos , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Estados UnidosRESUMO
The crystal structures of six different fibronectin Type III consensus-derived Tencon domains, whose solution properties exhibit no, to various degrees of, aggregation according to SEC, have been determined. The structures of the five variants showing aggregation reveal 3D domain swapped dimers. In all five cases, the swapping involves the C-terminal ß-strand resulting in the formation of Tencon dimers in which the target-binding surface is blocked. All of the variants differ in sequence in the FG loop, which is the hinge loop in the ß-strand-swapped dimers. The six tencon variants have between 0 and 5 residues inserted between positions 77 and 78 in the FG loop. Analysis of the structures suggests that a non-glycine residue at position 77 and insertions of <4 residues may destabilize the ß-turn in the FG loop promoting ß-strand swapping. Swapped dimers with an odd number of inserted residues may be less stable, particularly if they contain proline residues, because they cannot form perfect ß-bridges in the FG regions that link the swapped dimers. The Tencon ß-swapped variants with the longest FG sequences are observed to form higher order hexameric or helical oligomeric structures in the crystal correlating well with the aggregation properties of these domains observed in solution. Understanding the structural basis for domain-swapped dimerization and oligomerization will support engineering efforts of the Tencon domain to produce variants with desired biophysical properties.
Assuntos
Fibronectinas/química , Estrutura Terciária de Proteína , Proteínas Recombinantes de Fusão/química , Sequência de Aminoácidos , Cristalografia por Raios X , Fibronectinas/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de SequênciaRESUMO
Interleukin-17A (IL-17A) is the prototype of IL-17 family and has been implicated in the pathogenesis of a variety of autoimmune diseases. Therefore its structural and functional properties are of great medical interest. During our research on a recombinant human IL-17A (rhIL-17A) variant, four isoforms were obtained when it was refolded. While isoforms 1 and 2 represented non-covalent dimers, isoforms 3 and 4 were determined to be covalent dimers. All four isoforms were structurally similar by Circular Dichroism and fluorescence spectroscopy studies, but differential scanning calorimetry demonstrated thermal stability in the order of isoform 1=isoform 2Assuntos
Dissulfetos/metabolismo
, Interleucina-17/metabolismo
, Proteínas Recombinantes/metabolismo
, Sequência de Aminoácidos
, Varredura Diferencial de Calorimetria
, Dicroísmo Circular
, Eletroforese em Gel de Poliacrilamida
, Humanos
, Interleucina-17/química
, Espectrometria de Massas
, Dados de Sequência Molecular
, Peptídeos/química
, Peptídeos/metabolismo
, Isoformas de Proteínas/metabolismo
, Multimerização Proteica
, Redobramento de Proteína
, Soluções
, Espectrometria de Fluorescência
RESUMO
PURPOSE: Primary or acquired resistance to cetuximab, an antiepidermal growth factor receptor monoclonal antibody (mAb), minimizes its utility in recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). Aberrant hepatocyte growth factor/cMet pathway activation is an established resistance mechanism. Dual pathway targeting may overcome resistance. PATIENTS AND METHODS: This multicenter, randomized, noncomparative phase II study evaluated ficlatuzumab, an antihepatocyte growth factor mAb, with or without cetuximab in recurrent/metastatic HNSCC. The primary end point was median progression-free survival (PFS); an arm met significance criteria if the lower bound of the 90% CI excluded the historical control of 2 months. Key eligibility criteria were HNSCC with known human papillomavirus (HPV) status, cetuximab resistance (progression within 6 months of exposure in the definitive or recurrent/metastatic setting), and resistance to platinum and anti-PD-1 mAb. Secondary end points included objective response rate (ORR), toxicity, and the association of HPV status and cMet overexpression with efficacy. Continuous Bayesian futility monitoring was used. RESULTS: From 2018 to 2020, 60 patients were randomly assigned and 58 were treated. Twenty-seven versus 33 patients were allocated to monotherapy versus combination. Arms were balanced for major prognostic factors. The monotherapy arm closed early for futility. The combination arm met prespecified significance criteria with a median PFS of 3.7 months (lower bound 90% CI, 2.3 months; P = .04); the ORR was 6 of 32 (19%), including two complete and four partial responses. Exploratory analyses were limited to the combination arm: the median PFS was 2.3 versus 4.1 months (P = .03) and the ORR was 0 of 16 (0%) versus 6 of 16 (38%; P = .02) in the HPV-positive versus HPV-negative subgroups, respectively. cMet overexpression was associated with reduced hazard of progression in HPV-negative but not HPV-positive disease (P interaction = .02). CONCLUSION: The ficlatuzumab-cetuximab arm met significance criteria for PFS and warrants phase III development. HPV-negative HNSCC merits consideration as a selection criterion.
Assuntos
Neoplasias de Cabeça e Pescoço , Recidiva Local de Neoplasia , Humanos , Cetuximab , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Teorema de Bayes , Recidiva Local de Neoplasia/patologia , Anticorpos Monoclonais/uso terapêutico , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêuticoRESUMO
Glucagon-like peptide-2 (GLP-2) is a member of the glucagon multigene family that is produced by intestinal enteroendocrine cells in response to food intake. GLP-2 stimulates growth of the intestinal epithelium, enhances its barrier functions, and increases nutrient uptake. Therefore, a GLP-2 agonist may be efficacious in human diseases characterized by malabsorption or injury to the gastrointestinal epithelium. MIMETIBODY™ refers to a proprietary scaffold developed to extend the half-life of rapidly cleared peptides. It consists of a peptide linked to a scaffold that contains sequence elements from a human immunoglobulin G including those that allow recycling through the FcRn. The GLP-2 sequence was engineered into the MIMETIBODY™ scaffold. The primary state of both GLP-2 and the GLP-2 MIMETIBODY™ in DPBS was a noncovalently associated dimer indicative of self-interaction. The increased heterogeneity and the decreased lot-to-lot reproducibility caused by the self-interaction of therapeutic proteins are a challenge to drug development. A similar protein, GLP-1 MIMETIBODY™, contains the related GLP-1 peptide and does not form a dimer under similar conditions. Therefore, to minimize or abrogate dimerization, several variants were made by substituting GLP-2 amino acids with the corresponding amino acids from GLP-1. Molecular weight and secondary structure analyses reveal that substituting leucine for glutamine at position 17 (L17Q) reduces dimerization and α-helix content yet retains bioactivity.
Assuntos
Peptídeo 2 Semelhante ao Glucagon/química , Fragmentos de Peptídeos/química , Multimerização Proteica , Sequência de Aminoácidos , Substituição de Aminoácidos , Cromatografia em Gel , AMP Cíclico/biossíntese , Peptídeo 1 Semelhante ao Glucagon/química , Peptídeo 2 Semelhante ao Glucagon/genética , Receptor do Peptídeo Semelhante ao Glucagon 1 , Receptor do Peptídeo Semelhante ao Glucagon 2 , Células HEK293 , Humanos , Leucina/química , Leucina/genética , Dados de Sequência Molecular , Peso Molecular , Fragmentos de Peptídeos/biossíntese , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/farmacologia , Estrutura Quaternária de Proteína , Estrutura Secundária de Proteína , Receptores de Glucagon/agonistas , Receptores de Glucagon/metabolismoRESUMO
OBJECTIVES/HYPOTHESIS: To investigate the association of vitamin D level and perioperative complications in patients undergoing major head and neck surgery. STUDY DESIGN: Retrospective Cohort Study. METHODS: A retrospective chart review was performed for all patients undergoing reconstructive head and neck surgery between December 2017 and December 2019. Data regarding patient demographics, serum 25-hydroxyvitamin D (calcidiol) level, hospital course, prior radiation, and fistula formation were collected. Patients were categorized by serum calcidiol level as deficient (<20 ng/mL) or sufficient (â§20 ng/mL) and outcomes were compared between groups. RESULTS: Fifty-seven patients were included in the analysis. Average age at time of surgery was 62.6 ± 10.6 years. Patients with vitamin D levels <20 ng/mL were considered deficient and â§20 ng/mL were considered sufficient. Individuals in the deficient group (n = 29) had a mean serum calcidiol level of 13.95 ± 3.95 ng/mL, whereas those in the sufficient group (n = 28) had a mean calcidiol level of 28.53 ± 5.73 ng/mL. The rate of fistula was 41.4% in the deficient group, whereas patients in the sufficient group had a rate of fistula of 14.3% (P = .038). On multivariate analysis, higher serum calcidiol level above 20 ng/mL was associated with a lower likelihood of developing fistulae with an odds ratio 0.830 (95% confidence interval: 0.718-0.960, P = .012). CONCLUSION: Vitamin D deficiency may play a role in development of fistula after major head and neck surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:578-583, 2022.
Assuntos
Procedimentos Cirúrgicos Otorrinolaringológicos/efeitos adversos , Procedimentos de Cirurgia Plástica/efeitos adversos , Deficiência de Vitamina D/complicações , Idoso , Feminino , Neoplasias de Cabeça e Pescoço/complicações , Neoplasias de Cabeça e Pescoço/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Período Perioperatório , Estudos Retrospectivos , Resultado do Tratamento , Vitamina D/sangueRESUMO
OBJECTIVES/HYPOTHESIS: The aim of the study is to investigate whether close surgical margins impact oncologic outcomes compared to clear or involved surgical margins. We hypothesize that close surgical margins portend worse outcomes compared with clear margins, but improved outcomes compared with involved margins. STUDY DESIGN: Systematic review. METHODS: Using the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement standards, a systematic search was conducted for studies that reported oncologic outcomes following excision of primary mucosal head and neck squamous cell carcinoma (HNSCC). A meta-analysis was then performed, comparing local recurrence (LR), locoregional recurrence (LRR), and overall survival (OS) in patients with clear, close, and involved margins. RESULTS: Twenty-six studies met the inclusion criteria, totaling 8,435 patients. About 96% of our included cases involved the oral cavity, 2% involved the oropharynx, and 2% other. Also, 68% of cases were T1/T2 and 32% were T3/T4. On meta-analysis, clear margins were associated with lower incidence of 5-year LR relative risk (RR) 0.50, 95% confidence interval [CI] 0.38-0.65) and higher 5-year OS (RR 1.22, 1.11-1.35), when compared with close margins. Involved margins had higher incidence of 5-year LR (RR 1.75, 1.16-2.64), higher incidence of LRR at last follow-up (RR 1.66, 1.37-2.00), and no difference in 5-year OS (RR 0.82, 0.60-1.11), when compared with close margins. CONCLUSIONS: There is a stepwise improvement in oncologic outcomes as surgical margin categorically improves from involved to close to clear. Patients with close margins therefore may benefit from adjuvant therapy. Further research is required to investigate whether these findings are seen in non-oral cavity cases because they were underrepresented in this analysis. Laryngoscope, 132:307-321, 2022.
Assuntos
Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/cirurgia , Margens de Excisão , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/cirurgia , Humanos , Resultado do TratamentoRESUMO
A human interleukin-17A (IL-17A) variant was overexpressed in Escherichia coli BL21 (DE3) under the control of a T(7) promoter. The resulting insoluble inclusion bodies were isolated and solubilized by homogenization with 6 M guanidine HCl. The denatured recombinant human IL-17A variant was refolded in 20 mM Tris-HCl, pH 9.0, 500 mM arginine, 500 mM guanidine HCl, 15% glycerol, 1 mM cystamine, and 5 mM cysteine at 2-8°C for 40 h. The refolded IL-17A variant was subsequently purified using a combination of cation-exchange, reversed-phase and fluoroapatite chromatography. The final purified product was a monodisperse and crystallizable homodimer with a molecular weight of 30,348.3 Da. The protein was active in both receptor binding competition assay and IL-17A-dependent biological activity assay using human dermal fibroblasts.
Assuntos
Interleucina-17/química , Interleucina-17/metabolismo , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Redobramento de Proteína , Dicroísmo Circular , Escherichia coli/metabolismo , Humanos , Corpos de Inclusão/metabolismo , Interleucina-17/isolamento & purificação , Espectrometria de Massas , Isoformas de Proteínas/química , Isoformas de Proteínas/isolamento & purificação , Isoformas de Proteínas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismoRESUMO
Fab (fragment that having the antigen binding site) of a monoclonal antibody (mAb) is widely required in biopharmaceutical research and development. At Centocor, two routes of Fab production and purification were used to enable a variety of research and development efforts, particularly, crystallographic studies of antibody-antigen interactions. One route utilizes papain digestion of an intact monoclonal antibody for Fab fragment production. After digestion, separation of the Fab fragment from the Fc (fragment that crystallizes) and residual intact antibody was achieved using protein A affinity chromatography. In another route, His-tagged Fab fragments were obtained by transient expression of an appropriate construct in mammalian cells, and typical yields are 1-20mg of Fab fragment per liter of cell culture. The His-tagged Fab fragments were first captured using immobilized metal affinity chromatography (IMAC). To provide high quality protein sample for crystallization, Fabs from either proteolytic digestion or from direct expression were further purified using size-exclusion chromatography (SEC) and/or ion-exchange chromatography (IEC). The purified Fab fragments were characterized by mass spectrometry, SDS-PAGE, dynamic light scattering, and circular dichroism. Crystallization experiments demonstrated that the Fab fragments are of high quality to produce diffraction quality crystals suitable for X-ray crystallographic analysis.
Assuntos
Anticorpos Monoclonais/metabolismo , Fragmentos Fab das Imunoglobulinas/biossíntese , Fragmentos Fab das Imunoglobulinas/isolamento & purificação , Papaína/metabolismo , Anticorpos Monoclonais/química , Linhagem Celular , Dicroísmo Circular , Histidina/genética , Humanos , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/genética , Luz , Oligopeptídeos/genética , Papaína/química , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação , Espalhamento de Radiação , Difração de Raios XRESUMO
This chapter describes the conversion and assay development of a 96-well MK2-EGFP translocation assay into a higher density 384-well format high-content assay to be screened on the ArrayScan 3.1 imaging platform. The assay takes advantage of the well-substantiated hypothesis that mitogen-activated protein kinase-activating protein kinase-2 (MK2) is a substrate of p38 MAPK kinase and that p38-induced phosphorylation of MK-2 induces a nucleus-to-cytoplasm translocation. This chapter also presents a case history of the performance of the MK2-EGFP translocation assay, run as a "high-content" screen of a 32K kinase-biased library to identify p38 inhibitors. The assay performed very well and a number of putative p38 inhibitor hits were identified. Through the use of multiparameter data provided by the nuclear translocation algorithm and by checking images, a number of compounds were identified that were potential artifacts due to interference with the imaging format. These included fluorescent compounds, or compounds that dramatically reduced cell numbers due to cytotoxicity or by disrupting cell adherence. A total of 145 compounds produced IC(50) values <50.0 muM in the MK2-EGFP translocation assay, and a cross target query of the Lilly-RTP HTS database confirmed their inhibitory activity against in vitro kinase targets, including p38a. Compounds were confirmed structurally by LCMS analysis and profiled in cell-based imaging assays for MAPK signaling pathway selectivity. Three of the hit scaffolds identified in the MK2-EGFP translocation HCS run on the ArrayScan were selected for a p38a inhibitor hit-to-lead structure activity relationship (SAR) chemistry effort.
Assuntos
Técnicas de Química Combinatória/instrumentação , Proteínas de Fluorescência Verde/química , Proteínas Quinases/química , Proteínas Quinases p38 Ativadas por Mitógeno/química , Bioensaio/métodos , Adesão Celular , Núcleo Celular/metabolismo , Técnicas de Química Combinatória/métodos , Citoplasma/metabolismo , Biblioteca Gênica , Humanos , Concentração Inibidora 50 , Peptídeos e Proteínas de Sinalização Intracelular , Sistema de Sinalização das MAP Quinases , Fosforilação , Proteínas Serina-Treonina Quinases , Transporte Proteico , Translocação GenéticaRESUMO
We had shown previously that DNA polymerase beta (beta-pol) null mouse fibroblasts, deficient in base excision repair (BER), are hypersensitive to monofunctional methylating agents but not to hydrogen peroxide (H2O2). This is surprising because beta-pol is thought to be involved in BER of oxidative as well as methylated DNA damage. We confirm these findings here in early-passage cells. However, with time in culture, beta-pol null cells become hypersensitive to H2O2 and other reactive oxygen species-generating agents. Analysis of in vitro BER reveals a strong deficiency in single-nucleotide BER of 8-oxoguanine (8-oxoG) by both early- and late-passage beta-pol null cell extracts. Therefore, in early-passage wild-type and beta-pol null cells, the capacity for single-nucleotide BER of 8-oxoG does not correlate with cellular sensitivity to H2O2. Expression of beta-pol protein in the late-passage null cells almost completely reverses the H2O2-hypersensitivity phenotype. Methoxyamine (MX) treatment sensitizes late-passage wild-type cells to H2O2 as expected for beta-pol-mediated single-nucleotide BER; however in beta-pol null cells, MX has no effect. The data indicate a role(s) of beta-pol-dependent repair in protection against the cytotoxicity of oxidative DNA damage in wild-type cells.
Assuntos
Dano ao DNA/efeitos dos fármacos , DNA Polimerase beta/fisiologia , Reparo do DNA , Fibroblastos/enzimologia , Guanosina/análogos & derivados , Oxidantes/toxicidade , Animais , Antineoplásicos/toxicidade , Western Blotting , Divisão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citoproteção/fisiologia , DNA Polimerase beta/genética , Primers do DNA/química , DNA-Formamidopirimidina Glicosilase , Fibroblastos/efeitos dos fármacos , Glutationa/deficiência , Glutationa/metabolismo , Guanosina/metabolismo , Peróxido de Hidrogênio/toxicidade , Hidroxilaminas/toxicidade , Técnicas In Vitro , Camundongos , N-Glicosil Hidrolases/metabolismo , Ácido Peroxinitroso/toxicidade , Inibidores de Poli(ADP-Ribose) Polimerases , Poli(ADP-Ribose) Polimerases/efeitos dos fármacos , TransfecçãoAssuntos
Basigina/química , Sequência de Aminoácidos , Basigina/genética , Cristalografia por Raios X , Dimerização , Humanos , Modelos Moleculares , Peso Molecular , Estrutura Quaternária de Proteína , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genéticaRESUMO
When administered in serum, an efficacious therapeutic antibody should be homogeneous to minimize immune reactions or injection site irritation during administration. Monoclonal antibody (mAb) phase separation is one type of inhomogeneity observed in serum, and thus screening potential phase separation of mAbs in serum could guide lead optimization. However, serum contains numerous components, making it difficult to resolve mAb/serum mixtures at a scale amenable to analysis in a discovery setting. To address these challenges, a miniaturized assay was developed that combined confocal microscopy with Raman spectroscopy. The method was examined using CNTO607, a poorly-soluble anti-interleukin-13 human mAb, and CNTO3930, a soluble anti-respiratory syncytial virus humanized mAb. When CNTO607 was diluted into serum above 4.5 mg/mL, phase separation occurred, resulting in droplet formation. Raman spectra of droplet phases in mixtures included bands at 1240 and 1670 cm(-1), which are typical of mAb ß-sheets, and lacked bands at 1270 and 1655 cm(-1), which are typical of α-helices. The continuous phases included bands at 1270 and 1655 cm(-1) and lacked those at 1240 and 1670 cm(-1). Therefore, CNTO607 appeared to be sequestered within the droplets, while albumin and other α-helix-forming serum proteins remained within the continuous phases. In contrast, CNTO3930 formed only one phase, and its Raman spectra contained bands at 1240, 1670, 1270 and 1655 cm,(-1) demonstrating homogeneous distribution of components. Our results indicate that this plate-based method utilizing confocal Raman spectroscopy to probe liquid-liquid phases in mAb/serum mixtures can provide a screen for phase separation of mAb candidates in a discovery setting.
Assuntos
Anticorpos Monoclonais/sangue , Imunoglobulina G/sangue , Microscopia Confocal/métodos , Análise Espectral Raman/métodos , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/imunologia , Humanos , Imunoglobulina G/administração & dosagem , Imunoglobulina G/imunologia , Interleucina-13/imunologia , Reprodutibilidade dos Testes , Vírus Sinciciais Respiratórios/imunologiaRESUMO
Peptidomimetics effective in modulating protein-protein interactions and resistant to proteolysis have potential in therapeutic applications. An appealing yet underperforming peptidomimetic strategy is to employ D-amino acids and reversed sequences to mimic a lead peptide conformation, either separately or as the combined retro-inverso peptide. In this work, we examine the conformations of inverse, reverse and retro-inverso peptides of p53(15-29) using implicit solvent molecular dynamics simulation and circular dichroism spectroscopy. In order to obtain converged ensembles for the peptides, we find enhanced sampling is required via the replica exchange molecular dynamics method. From these replica exchange simulations, the D-peptide analogues of p53(15-29) result in a predominantly left-handed helical conformation. When the parent sequence is reversed sequence as either the L-peptide and D-peptide, these peptides display a greater helical propensity, feature reflected by NMR and CD studies in TFE/water solvent. The simulations also indicate that, while approximately similar orientations of the side-chains are possible by the peptide analogues, their ability to mimic the parent peptide is severely compromised by backbone orientation (for D-amino acids) and side-chain orientation (for reversed sequences). A retro-inverso peptide is disadvantaged as a mimic in both aspects, and further chemical modification is required to enable this concept to be used fruitfully in peptidomimetic design. The replica exchange molecular simulation approach adopted here, with its ability to provide detailed conformational insights into modified peptides, has potential as a tool to guide structure-based design of new improved peptidomimetics.
Assuntos
Peptídeos/química , Proteína Supressora de Tumor p53/química , Sequência de Aminoácidos , Aminoácidos/química , Dicroísmo Circular , Cristalografia por Raios X , Ligação de Hidrogênio , Modelos Moleculares , Simulação de Dinâmica Molecular , Mimetismo Molecular , Dados de Sequência Molecular , Peptídeos/metabolismo , Estrutura Secundária de Proteína , Proteínas Proto-Oncogênicas c-mdm2/química , Proteínas Proto-Oncogênicas c-mdm2/metabolismoRESUMO
Interleukin (IL)-12 and IL-23 are heterodimeric proinflammatory cytokines that share a common p40 subunit, paired with p35 and p19 subunits, respectively. They represent an attractive class of therapeutic targets for the treatment of psoriasis and other immune-mediated diseases. Ustekinumab is a fully human monoclonal antibody (mAb) that binds specifically to IL-12/IL-23p40 and neutralizes human IL-12 and IL-23 bioactivity. The crystal structure of ustekinumab Fab (antigen binding fragment of mAb), in complex with human IL-12, has been determined by X-ray crystallography at 3.0 Å resolution. Ustekinumab Fab binds the D1 domain of the p40 subunit in a 1:1 ratio in the crystal, consistent with a 2 cytokines:1 mAb stoichiometry, as measured by isothermal titration calorimetry. The structure indicates that ustekinumab binds to the same epitope on p40 in both IL-12 and IL-23 with identical interactions. Mutational analyses confirm that several residues identified in the IL-12/IL-23p40 epitope provide important molecular binding interactions with ustekinumab. The electrostatic complementarity between the mAb antigen binding site and the p40 D1 domain epitope appears to play a key role in antibody/antigen recognition specificity. Interestingly, this structure also reveals significant structural differences in the p35 subunit and p35/p40 interface, compared with the published crystal structure of human IL-12, suggesting unusual and potentially functionally relevant structural flexibility of p35, as well as p40/p35 recognition. Collectively, these data describe unique observations about IL-12p35 and ustekinumab interactions with p40 that account for its dual binding and neutralization of IL-12 and IL-23.
Assuntos
Anticorpos Monoclonais/química , Anticorpos Monoclonais/metabolismo , Fatores Imunológicos/química , Fatores Imunológicos/metabolismo , Interleucina-12/metabolismo , Interleucina-23/metabolismo , Substituição de Aminoácidos/genética , Anticorpos Monoclonais Humanizados , Calorimetria , Cristalografia por Raios X , Epitopos/genética , Epitopos/imunologia , Humanos , Interleucina-12/genética , Interleucina-23/genética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Ligação Proteica , Estrutura Quaternária de Proteína , UstekinumabRESUMO
Protein aggregation is of great concern to pharmaceutical formulations and has been implicated in several diseases. We engineered an anti-IL-13 monoclonal antibody CNTO607 for improved solubility. Three structure-based engineering approaches were employed in this study: (i) modifying the isoelectric point (pI), (ii) decreasing the overall surface hydrophobicity and (iii) re-introducing an N-linked carbohydrate moiety within a complementarity-determining region (CDR) sequence. A mutant was identified with a modified pI that had a 2-fold improvement in solubility while retaining the binding affinity to IL-13. Several mutants with decreased overall surface hydrophobicity also showed moderately improved solubility while maintaining a similar antigen affinity. Structural studies combined with mutagenesis data identified an aggregation 'hot spot' in heavy-chain CDR3 (H-CDR3) that contains three residues ((99)FHW(100a)). The same residues, however, were found to be essential for high affinity binding to IL-13. On the basis of the spatial proximity and germline sequence, we reintroduced the consensus N-glycosylation site in H-CDR2 which was found in the original antibody, anticipating that the carbohydrate moiety would shield the aggregation 'hot spot' in H-CDR3 while not interfering with antigen binding. Peptide mapping and mass spectrometric analysis revealed that the N-glycosylation site was generally occupied. This variant showed greatly improved solubility and bound to IL-13 with affinity similar to CNTO607 without the N-linked carbohydrate. All three engineering approaches led to improved solubility and adding an N-linked carbohydrate to the CDR was the most effective route for enhancing the solubility of CNTO607.
Assuntos
Anticorpos Monoclonais/química , Conformação Proteica , Engenharia de Proteínas/métodos , Estabilidade Proteica , Sequência de Aminoácidos , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/metabolismo , Sítios de Ligação , Varredura Diferencial de Calorimetria , Eletroforese em Gel de Poliacrilamida , Humanos , Interações Hidrofóbicas e Hidrofílicas , Interleucina-13/antagonistas & inibidores , Interleucina-13/metabolismo , Focalização Isoelétrica , Ponto Isoelétrico , Modelos Moleculares , Dados de Sequência Molecular , Mapeamento de Peptídeos , Multimerização Proteica , Solubilidade , TemperaturaRESUMO
We prepared and characterized golimumab (CNTO148), a human IgG1 tumor necrosis factor alpha (TNFα) antagonist monoclonal antibody chosen for clinical development based on its molecular properties. Golimumab was compared with infliximab, adalimumab and etanercept for affinity and in vitro TNFα neutralization. The affinity of golimumab for soluble human TNFα, as determined by surface plasmon resonance, was similar to that of etanercept (18 pM versus 11 pM), greater than that of infliximab (44 pM) and significantly greater than that of adalimumab (127 pM, p=0.018). The concentration of golimumab necessary to neutralize TNFα-induced E-selectin expression on human endothelial cells by 50% was significantly less than those for infliximab (3.2 fold; p=0.017) and adalimumab (3.3-fold; p=0.008) and comparable to that for etanercept. The conformational stability of golimumab was greater than that of infliximab (primary melting temperature [Tm] 74.8 °C vs. 69.5 °C) as assessed by differential scanning calorimetry. In addition, golimumab showed minimal aggregation over the intended shelf life when formulated as a high concentration liquid product (100 mg/mL) for subcutaneous administration. In vivo, golimumab at doses of 1 and 10 mg/kg significantly delayed disease progression in a mouse model of human TNFα-induced arthritis when compared with untreated mice, while infliximab was effective only at 10 mg/kg. Golimumab also significantly reduced histological scores for arthritis severity and cartilage damage, as well as serum levels of pro-inflammatory cytokines and chemokines associated with arthritis. Thus, we have demonstrated that golimumab is a highly stable human monoclonal antibody with high affinity and capacity to neutralize human TNFα in vitro and in vivo.
Assuntos
Anticorpos Monoclonais/farmacologia , Artrite/imunologia , Cartilagem/efeitos dos fármacos , Imunoglobulina G/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Adalimumab , Animais , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Monoclonais Humanizados/farmacologia , Afinidade de Anticorpos , Artrite/induzido quimicamente , Cartilagem/patologia , Modelos Animais de Doenças , Progressão da Doença , Selectina E/genética , Selectina E/metabolismo , Etanercepte , Regulação da Expressão Gênica/efeitos dos fármacos , Hibridomas , Imunoglobulina G/isolamento & purificação , Mediadores da Inflamação/metabolismo , Infliximab , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Conformação Proteica , Receptores do Fator de Necrose Tumoral , Fator de Necrose Tumoral alfa/imunologiaRESUMO
HTS of the compound collection for inhibition of the HCV RNA dependent RNA polymerase identified two 168 member N-acyl pyrrolidine combinatorial mixture hits. Deconvolution and expansion of these mixtures by solid phase synthesis to establish initial SAR and identify a potent inhibitor is reported.