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1.
Bioconjug Chem ; 30(9): 2340-2348, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31380623

RESUMO

The normal electron-demand Diels-Alder (DA) cycloaddition is a classic transformation routinely used in synthesis; however, applications in biological systems are limited. Here, we report a spiro[2.4]hepta-4,6-diene-containing noncanonical amino acid (SCpHK) capable of efficient incorporation into antibodies and subsequent coupling with maleimide via a DA reaction. SCpHK was stable throughout protein expression in mammalian cells and enabled covalent attachment of maleimide drug-linkers yielding DA antibody-drug conjugates (DA-ADCs) with nearly quantitative conversion in a one-step process. The uncatalyzed DA reaction between SCpHK and maleimide in aqueous buffer was rapid (1.8-5.4 M-1 s-1), and the antibody-drug adduct was stable in rat serum for at least 1 week at 37 °C. Anti-EphA2 DA-ADCs containing AZ1508 or SG3249 maleimide drug-linkers were potent inhibitors of tumor growth in PC3 tumor models in vivo. The DA bioconjugation strategy described here represents a simple method to produce site-specific and stable ADCs with maleimide drug-linkers.


Assuntos
Imunoconjugados/química , Maleimidas/química , Animais , Células CHO , Sobrevivência Celular/efeitos dos fármacos , Cricetulus , Reação de Cicloadição , Humanos , Imunoconjugados/farmacologia , Modelos Moleculares , Células PC-3 , Conformação Proteica , Compostos de Espiro/química
2.
PLoS Genet ; 12(4): e1005895, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27093186

RESUMO

Small cell lung cancer (SCLC) is an aggressive disease with poor survival. A few sequencing studies performed on limited number of samples have revealed potential disease-driving genes in SCLC, however, much still remains unknown, particularly in the Asian patient population. Here we conducted whole exome sequencing (WES) and transcriptomic sequencing of primary tumors from 99 Chinese SCLC patients. Dysregulation of tumor suppressor genes TP53 and RB1 was observed in 82% and 62% of SCLC patients, respectively, and more than half of the SCLC patients (62%) harbored TP53 and RB1 mutation and/or copy number loss. Additionally, Serine/Arginine Splicing Factor 1 (SRSF1) DNA copy number gain and mRNA over-expression was strongly associated with poor survival using both discovery and validation patient cohorts. Functional studies in vitro and in vivo demonstrate that SRSF1 is important for tumorigenicity of SCLC and may play a key role in DNA repair and chemo-sensitivity. These results strongly support SRSF1 as a prognostic biomarker in SCLC and provide a rationale for personalized therapy in SCLC.


Assuntos
Carcinoma de Células Pequenas/genética , Neoplasias Pulmonares/genética , Proteínas Oncogênicas/genética , Fatores de Processamento de Serina-Arginina/genética , Adulto , Idoso , Variações do Número de Cópias de DNA , Dano ao DNA , Feminino , Inativação Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Mutação
3.
Bioconjug Chem ; 29(7): 2406-2414, 2018 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-29932647

RESUMO

The thiol-maleimide linkage is widely used for antibody-drug conjugate (ADC) production; however, conjugation of maleimide-drugs could be improved by simplified procedures and reliable conjugate stability. Here, we report the evaluation of electron-rich and cyclic dienes that can be appended to antibodies and reacted with maleimide-containing drugs through the Diels-Alder (DA) reaction. Drug conjugation is fast and quantitative due to reaction acceleration in water, and the linkage is more stable in serum than in the corresponding thiol-maleimide adduct with the same drug. ADCs produced using the DA reaction (DAADCs) are effective in vitro and in vivo, demonstrating the utility of this reaction in producing effective biotherapeutics. Given the large number of commercially available maleimide compounds, this conjugation approach could be readily applied to the production of a wide range of antibody (or protein) conjugates.


Assuntos
Reação de Cicloadição/métodos , Imunoconjugados/química , Maleimidas/química , Alcenos , Anticorpos/química , Reagentes de Ligações Cruzadas/química , Estabilidade de Medicamentos , Maleimidas/uso terapêutico , Preparações Farmacêuticas/química
4.
Chem Rec ; 18(7-8): 840-848, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29286199

RESUMO

Oxygen reduction reaction (ORR) is the crucial step of various renewable energy conversion and storage technologies such as fuel cells and air-batteries. Cobalt-based electrocatalysts including oxides/chalcogenides and Co-Nx /C, one kind of non-precious metal electrocatalysts with competitive activity, enhanced durability, and acceptable cost, have been proposed as the potentially interesting alternatives to Pt-based electrocatalysts. In this account, we summarized the synthesis methods and the corresponding main impact factors including ligand effect, particle size effect, crystal structure, nanostructure, defects and active centers related to the ORR performance on both of oxides/chalcogenides and Co-Nx /C. Some special points have been discussed on design and synthesis of low-cost and high-performance cobalt-based electrocatalysts with enhanced electrocatalytic activity. Also, the current challenges and future trends are proposed for improving the performance of Co-involving electrocatalysts.

5.
Mol Pharm ; 14(5): 1501-1516, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28245132

RESUMO

Antibody-drug conjugates (ADCs) are a class of biopharmaceuticals that combine the specificity of antibodies with the high-potency of cytotoxic drugs. Engineering cysteine residues in the antibodies using mutagenesis is a common method to prepare site-specific ADCs. With this approach, solvent accessible amino acids in the antibody have been selected for substitution with cysteine for conjugating maleimide-bearing cytotoxic drugs, resulting in homogeneous and stable site-specific ADCs. Here we describe a cysteine engineering approach based on the insertion of cysteines before and after selected sites in the antibody, which can be used for site-specific preparation of ADCs. Cysteine-inserted antibodies have expression level and monomeric content similar to the native antibodies. Conjugation to a pyrrolobenzodiazepine dimer (SG3249) resulted in comparable efficiency of site-specific conjugation between cysteine-inserted and cysteine-substituted antibodies. Cysteine-inserted ADCs were shown to have biophysical properties, FcRn, and antigen binding affinity similar to the cysteine-substituted ADCs. These ADCs were comparable for serum stability to the ADCs prepared using cysteine-mutagenesis and had selective and potent cytotoxicity against human prostate cancer cells. Two of the cysteine-inserted variants abolish binding of the resulting ADCs to FcγRs in vitro, thereby potentially preventing non-target mediated uptake of the ADCs by cells of the innate immune system that express FcγRs, which may result in mitigating off-target toxicities. A selected cysteine-inserted ADC demonstrated potent dose-dependent anti-tumor activity in a xenograph tumor mouse model of human breast adenocarcinoma expressing the oncofetal antigen 5T4.


Assuntos
Anticorpos Monoclonais/química , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Cisteína/química , Animais , Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/uso terapêutico , Linhagem Celular Tumoral , Feminino , Humanos , Imunoconjugados/química , Imunoconjugados/uso terapêutico , Neoplasias Mamárias Experimentais/tratamento farmacológico , Camundongos , Camundongos Nus , Trastuzumab/química , Trastuzumab/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Bioconjug Chem ; 26(10): 2085-96, 2015 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-26340339

RESUMO

Antibody-drug conjugates (ADCs) have emerged as an important class of therapeutics for cancer treatment that combine the target specificity of antibodies with the killing activity of anticancer chemotherapeutics. Early conjugation technologies relied upon random conjugation to either lysine or cysteine residues, resulting in heterogeneous ADCs. Recent technology advancements have resulted in the preparation of homogeneous ADCs through the site-specific conjugation at engineered cysteines, glycosylated amino acids, and bioorthogonal unnatural amino acids. Here we describe for the first time the conjugation of an anti-mitotic drug to an antibody following the mild and selective oxidation of a serine residue engineered at the N-terminus of the light chain. Using an alkoxyamine-derivatized monomethyl auristatine E payload, we have prepared a hydrolytically stable ADC that retains binding to its antigen and displays potent in vitro cytotoxicity and in vivo tumor growth inhibition.


Assuntos
Anticorpos/química , Anticorpos/farmacologia , Engenharia de Proteínas/métodos , Animais , Anticorpos/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Humanos , Hidrólise , Camundongos Nus , Oximas/química , Estabilidade Proteica , Ratos , Receptor EphA2/imunologia , Receptor EphA2/metabolismo , Serina/química , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Mol Cancer Ther ; 22(4): 539-550, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36696581

RESUMO

Antibodies targeting insulin-like growth factor 1 receptor (IGF-1R) induce objective responses in only 5% to 15% of children with sarcoma. Understanding the mechanisms of resistance may identify combination therapies that optimize efficacy of IGF-1R-targeted antibodies. Sensitivity to the IGF-1R-targeting antibody TZ-1 was determined in rhabdomyosarcoma and Ewing sarcoma cell lines. Acquired resistance to TZ-1 was developed and characterized in sensitive Rh41 cells. The BRD4 inhibitor, JQ1, was evaluated as an agent to prevent acquired TZ-1 resistance in Rh41 cells. The phosphorylation status of receptor tyrosine kinases (RTK) was assessed. Sensitivity to TZ-1 in vivo was determined in Rh41 parental and TZ-1-resistant xenografts. Of 20 sarcoma cell lines, only Rh41 was sensitive to TZ-1. Cells intrinsically resistant to TZ-1 expressed multiple (>10) activated RTKs or a relatively less complex set of activated RTKs (∼5). TZ-1 decreased the phosphorylation of IGF-1R but had little effect on other phosphorylated RTKs in all resistant lines. TZ-1 rapidly induced activation of RTKs in Rh41 that was partially abrogated by knockdown of SOX18 and JQ1. Rh41/TZ-1 cells selected for acquired resistance to TZ-1 constitutively expressed multiple activated RTKs. TZ-1 treatment caused complete regressions in Rh41 xenografts and was significantly less effective against the Rh41/TZ-1 xenograft. Intrinsic resistance is a consequence of redundant signaling in pediatric sarcoma cell lines. Acquired resistance in Rh41 cells is associated with rapid induction of multiple RTKs, indicating a dynamic response to IGF-1R blockade and rapid development of resistance. The TZ-1 antibody had greater antitumor activity against Rh41 xenografts compared with other IGF-1R-targeted antibodies tested against this model.


Assuntos
Proteínas Nucleares , Sarcoma , Criança , Humanos , Fatores de Transcrição , Receptor IGF Tipo 1 , Sarcoma/tratamento farmacológico , Receptores de Somatomedina , Anticorpos Monoclonais/farmacologia , Linhagem Celular Tumoral , Proteínas de Ciclo Celular , Fatores de Transcrição SOXF
8.
Materials (Basel) ; 15(3)2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35160841

RESUMO

It is of great interest and importance to resource utilization of waste biomass to produce porous carbon for environmental treatments. Pore structure and properties of the obtained carbon mainly relate to carbonization conditions and biomass types. In this work, a series of porous, biomass-activated carbons (AC) were prepared using shaddock peel, with ZnCl2 as a pore-forming agent. The effect of carbonization temperature and the mass ratio between ZnCl2 and shaddock peel were thoroughly investigated. The material composition, surface chemical properties, and surface structures of samples were carefully characterized. The specific surface area and adsorption capacity to methylene blue (MB) of adsorbents were changed with the carbonization temperature and the mass ratios between ZnCl2 and shaddock peel; when the temperature was at 1000 °C and the mass ratio was equal to 2:1, the resulting adsorbent had the largest specific surface area of 2398.74 m2/g and average pore size of 3.04 nm, which showed the highest adsorption capacity to MB to be 869.57 mg/g. The adsorption processes of biomass AC adsorbent matched the pseudo-second-order kinetic model and Langmuir isotherm model. This efficient and environmentally friendly biomass AC adsorbent from shaddock peel, activated by ZnCl2, is a promising candidate for the treatment of water pollution.

9.
Ann Transl Med ; 9(4): 336, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33708963

RESUMO

BACKGROUND: To summarise the ultrasound manifestations of coronavirus disease-19 (COVID-19) patients with lung lesions and explore the clinical value of bedside ultrasound in the identification of patients at risk of progression to severe disease. METHODS: This retrospective study enrolled 31 patients with COVID-19 who were admitted to our hospital from January 18 to February 5, 2020. Lung ultrasounds were performed in all cases to evaluate the ultrasound manifestations of the patient's lung lesions and to determine the lung ultrasound scores (LUS). The Cox proportional hazards regression model was used for the multifactor analysis of 7 candidate parameters, including the LUS and the oxygenation index (PaO2/FiO2). Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of the LUS. RESULTS: Lung ultrasound images of COVID-19 patients mainly reflected the presence of interstitial pulmonary lesions (90.3%, 28/31). The lung lesions were primarily distributed in the subpleural and peripheral pulmonary zones. Multivariate analyses identified the oxygenation index, the LUS, and the lymphocyte count as factors related to the progression to severe-critical disease in COVID-19 patients (P<0.05). With a cut-off value of 9.5, the area under the ROC curve was 0.910. The LUS showed a sensitivity and specificity of 81.3% and 93.0%, respectively (P≤0.001), with an overall accuracy of 75%. CONCLUSIONS: The lung ultrasound findings in COVID-19 patients were mainly and specifically manifested as interstitial lesions involving the peripheral zones of the lung. In addition, ultrasound imaging could predict the likelihood of COVID-19 patients progressing to severe disease, thereby allowing for early intervention. Thus, lung ultrasounds have great clinical value in monitoring and evaluating COVID-19 patients.

11.
Nat Commun ; 12(1): 3136, 2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-34035291

RESUMO

Structural degradation in manganese oxides leads to unstable electrocatalytic activity during long-term cycles. Herein, we overcome this obstacle by using proton exchange on well-defined layered Li2MnO3 with an O3-type structure to construct protonated Li2-xHxMnO3-n with a P3-type structure. The protonated catalyst exhibits high oxygen reduction reaction activity and excellent stability compared to previously reported cost-effective Mn-based oxides. Configuration interaction and density functional theory calculations indicate that Li2-xHxMnO3-n has fewer unstable O 2p holes with a Mn3.7+ valence state and a reduced interlayer distance, originating from the replacement of Li by H. The former is responsible for the structural stability, while the latter is responsible for the high transport property favorable for boosting activity. The optimization of both charge states to reduce unstable O 2p holes and crystalline structure to reduce the reaction pathway is an effective strategy for the rational design of electrocatalysts, with a likely extension to a broad variety of layered alkali-containing metal oxides.

12.
ACS Appl Mater Interfaces ; 12(19): 21605-21615, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32309924

RESUMO

A series of cobalt-based multicomponent electrocatalysts (Co-Cat-T) for the oxygen reduction reaction (ORR) were synthesized by thermal pyrolysis of activated carbon-supported cobalt and melamine mixture from 500 to 800 °C. Their corresponding electrocatalytic performance was systematically investigated toward ORR in an alkaline electrolyte. The electrocatalyst chemical composition and structure evolution (e.g., microstrain, crystallite size, and cell volume) were confirmed by X-ray diffraction Rietveld analyses. The material generated at 550 °C (Co-Cat-T550) showed the largest cell volume of the C3N4 phase with a crystallite size of 4.1 ± 0.1 nm. Independent of the heat-treatment temperature, the cobalt atom was coordinated to nitrogen moieties. The following findings: cobalt inserted in the carbon nitride framework (Co-g-C3N4), abundant Co-Nx and pyridinic-N species, unique encapsulated cross-tubular structure, and disordered carbon domains performed better in the ORR with Co-Cat-T550 among the obtained electrocatalysts. In addition, Co-Cat-T550 showed performance comparable to Pt/C in an alkaline hydrogen/oxygen microfuel cell platform.

13.
PLoS One ; 15(6): e0234268, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497150

RESUMO

Annexin A1 (anxA1) is an immunomodulatory protein that has been proposed as a tumor vascular target for antitumor biologic agents, yet to date the vascular expression of anxA1 in specific tumor indications has not been systematically assessed. Attempts to evaluate vascular anxA1 expression by immunohistochemistry are complicated by a lack of available antibodies that are both specific for anxA1 and bind the N-terminal-truncated form of anxA1 that has previously been identified in tumor vasculature. To study the vascular expression pattern of anxA1 in non-small-cell lung carcinoma (NSCLC), we isolated an antibody capable of binding N-terminal-truncated anxA127-346 and employed it in immunohistochemical studies of human lung specimens. Lung tumor specimens evaluated with this antibody revealed vascular (endothelial) anxA1 expression in five of eight tumor samples studied, but no vascular anxA1 expression was observed in normal lung tissue. Tumor microarray analysis further demonstrated positive vascular staining for anxA1 in 30 of 80 NSCLC samples, and positive staining of neoplastic cells was observed in 54 of 80 samples. No correlation was observed between vascular and parenchymal anxA1 expression. Two rodent tumor models, B16-F10 and Py230, were determined to have upregulated anxA1 expression in the intratumoral vasculature. These data validate anxA1 as a potential vascular anti-tumor target in a subset of human lung tumors and identify rodent models which demonstrate anxA1 expression in tumor vasculature.


Assuntos
Anexina A1/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , Regulação para Cima , Animais , Carcinoma Pulmonar de Células não Pequenas/irrigação sanguínea , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Humanos , Neoplasias Pulmonares/irrigação sanguínea , Camundongos
14.
Mol Cancer Ther ; 18(1): 89-99, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30352801

RESUMO

Pyrrolobenzodiazepine dimers (PBD) form cross-links within the minor groove of DNA causing double-strand breaks (DSB). DNA repair genes such as BRCA1 and BRCA2 play important roles in homologous recombination repair of DSB. We hypothesized that PBD-based antibody-drug conjugates (ADC) will have enhanced killing of cells in which homologous recombination processes are defective by inactivation of BRCA1 or BRCA2 genes. To support this hypothesis, we found 5T4-PBD, a PBD-dimer conjugated to anti-5T4 antibody, elicited more potent antitumor activity in tumor xenografts that carry defects in DNA repair due to BRCA mutations compared with BRCA wild-type xenografts. To delineate the role of BRCA1/2 mutations in determining sensitivity to PBD, we used siRNA knockdown and isogenic BRCA1/2 knockout models to demonstrate that BRCA deficiency markedly increased cell sensitivity to PBD-based ADCs. To understand the translational potential of treating patients with BRCA deficiency using PBD-based ADCs, we conducted a "mouse clinical trial" on 23 patient-derived xenograft (PDX) models bearing mutations in BRCA1 or BRCA2 Of these PDX models, 61% to 74% had tumor stasis or regression when treated with a single dose of 0.3 mg/kg or three fractionated doses of 0.1 mg/kg of a PBD-based ADC. Furthermore, a suboptimal dose of PBD-based ADC in combination with olaparib resulted in significantly improved antitumor effects, was not associated with myelotoxicity, and was well tolerated. In conclusion, PBD-based ADC alone or in combination with a PARP inhibitor may have improved therapeutic window in patients with cancer carrying BRCA mutations.


Assuntos
Antineoplásicos Imunológicos/administração & dosagem , Benzodiazepinas/química , Imunoconjugados/administração & dosagem , Neoplasias Experimentais/tratamento farmacológico , Ftalazinas/administração & dosagem , Piperazinas/administração & dosagem , Inibidores de Poli(ADP-Ribose) Polimerases/administração & dosagem , Pirróis/química , Administração Intravenosa , Animais , Antineoplásicos Imunológicos/química , Antineoplásicos Imunológicos/farmacologia , Proteína BRCA1/genética , Proteína BRCA2/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Células HeLa , Humanos , Imunoconjugados/química , Imunoconjugados/farmacologia , Glicoproteínas de Membrana/antagonistas & inibidores , Camundongos , Mutação , Neoplasias Experimentais/genética , Ftalazinas/farmacologia , Piperazinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Sequenciamento do Exoma , Ensaios Antitumorais Modelo de Xenoenxerto
15.
MAbs ; 11(3): 500-515, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30835621

RESUMO

Most strategies used to prepare homogeneous site-specific antibody-drug conjugates (ADCs) result in ADCs with a drug-to-antibody ratio (DAR) of two. Here, we report a disulfide re-bridging strategy to prepare homogeneous ADCs with DAR of one using a dual-maleimide pyrrolobenzodiazepine (PBD) dimer (SG3710) and an engineered antibody (Flexmab), which has only one intrachain disulfide bridge at the hinge. We demonstrate that SG3710 efficiently re-bridge a Flexmab targeting human epidermal growth factor receptor 2 (HER2), and the resulting ADC was highly resistant to payload loss in serum and exhibited potent anti-tumor activity in a HER2-positive gastric carcinoma xenograft model. Moreover, this ADC was tolerated in rats at twice the dose compared to a site-specific ADC with DAR of two prepared using a single-maleimide PBD dimer (SG3249). Flexmab technologies, in combination with SG3710, provide a platform for generating site-specific homogenous PBD-based ADCs with DAR of one, which have improved biophysical properties and tolerability compared to conventional site-specific PBD-based ADCs with DAR of two.


Assuntos
Antineoplásicos , Benzodiazepinas/química , Imunoconjugados , Pirróis/química , Receptor ErbB-2/antagonistas & inibidores , Neoplasias Gástricas/tratamento farmacológico , Trastuzumab , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Feminino , Humanos , Imunoconjugados/química , Imunoconjugados/farmacologia , Células MCF-7 , Camundongos Nus , Ratos , Receptor ErbB-2/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Trastuzumab/química , Trastuzumab/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Int J Radiat Biol ; 84(5): 401-12, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18464069

RESUMO

PURPOSE: Velafermin (recombinant human fibroblast growth factor-20, rhFGF-20) has been shown to reduce the severity and duration of mucositis in preclinical acute (single dose) radiation and chemotherapy/radiation models of oral mucositis. Our present study assessed the impact of velafermin on the severity and duration of oral mucositis that occurred as a consequence of fractionated radiation. EXPERIMENTAL DESIGN: Male Golden Syrian hamsters were exposed to eight doses of radiation (7.5 Gy/dose) to the cheek pouch on days 0, 1, 2, 3, 6, 7, 8 and 9 that resulted in severe mucositis. Velafermin (4 mg/kg intraperitoneally) was administered on days 3 and 9; days 2, 3, 8 and 9; days 3, 4, 9 and 10; or days 4, 5, 10 and 11. RESULTS: Although all velafermin-treated groups showed some reduction in the degree of mucositis relative to the vehicle control, the most significant reduction (p < 0.001) was observed in the groups treated on days 3 and 9 or on days 4, 5, 10 and 11. Further histological analysis of resected buccal mucosa revealed improvements in epithelial tissue degradation, connective tissue degradation and inflammation severity after velafermin treatment. Most notably, velafermin treatment reduced inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor (TNF) production possibly through nuclear factor-kappaB (NF-kappaB) mediation. The detection of increased NF-E2-related factor-2 (NRF-2) expression in the early onset stage of mucositis in the buccal mucosa suggested additional protective benefits from reactive oxygen species (ROS) generated as a consequence of fractionated radiation treatment. CONCLUSION: Thus, velafermin provided therapeutic benefit in a hamster model of oral mucositis induced by fractionated radiation therapy.


Assuntos
Fatores de Crescimento de Fibroblastos/química , Fatores de Crescimento de Fibroblastos/farmacologia , Mucosa Bucal/patologia , Lesões por Radiação/tratamento farmacológico , Estomatite/tratamento farmacológico , Animais , Bochecha , Cricetinae , Epitélio/efeitos da radiação , Humanos , Inflamação/radioterapia , Interleucina-6/biossíntese , Masculino , Fator 2 Relacionado a NF-E2/biossíntese , NF-kappa B/biossíntese , Fator de Necrose Tumoral alfa/biossíntese
17.
Oncotarget ; 9(33): 22960-22975, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29796165

RESUMO

Despite recent advances in treatment, breast cancer remains the second-most common cause of cancer death among American women. A greater understanding of the molecular characteristics of breast tumors could ultimately lead to improved tumor-targeted treatment options, particularly for subsets of breast cancer patients with unmet needs. Using an unbiased genomics approach to uncover membrane-localized tumor-associated antigens (TAAs), we have identified glial cell line derived neurotrophic factor (GDNF) family receptor α 1 (GFRA1) as a breast cancer TAA. Immunohistochemistry (IHC) revealed that GFRA1 displays a limited normal tissue expression profile coupled with overexpression in specific breast cancer subsets. The cell surface localization as determined by fluorescence-activated cell sorting (FACS) and the rapid internalization kinetics of GFRA1 makes it an ideal target for therapeutic exploitation as an antibody-drug conjugate (ADC). Here, we describe the development of a pyrrolobenzodiazepine (PBD)-armed, GFRA1-targeted ADC that demonstrates cytotoxicity in GFRA1-positive cell lines and patient-derived xenograft (PDX) models. The safety profile of the rat cross-reactive GFRA1-PBD was assessed in a rat toxicology study to find transient cellularity reductions in the bone marrow and peripheral blood, consistent with known off-target effects of PBD ADC's. These studies reveal no evidence of on-target toxicity and support further evaluation of GFRA1-PBD in GFRA1-positive tumors.

18.
Cancer Chemother Pharmacol ; 60(3): 423-35, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17541593

RESUMO

PURPOSE: To investigate the pharmacological properties of the CR011-vcMMAE fully human antibody-drug conjugate (ADC), such as dose titrations, quantitation of the time (days) to complete regression, pharmacokinetics, and schedule dependency. Our prior study characterized a fully human antibody to GPNMB covalently linked to monomethylauristatin E, CR011-vcMMAE, and further demonstrated cell surface staining of melanoma lines susceptible to the immunoconjugate's cytotoxicity (Clin Cancer Res 2005; 12(4): 1373-1382). METHODS: The human SK-MEL-2 and SK-MEL-5 melanoma xenografts were used in athymic mice to assess anti-tumor efficacy. After s.c. implantation, tumors became established (60-100 mg), and treatment commenced by i.v. injection of the immunoconjugate or vinblastine or paclitaxel. Short-term anti-tumor effects (inhibition of tumor growth) and long-term effects (complete regression) were observed. RESULTS: CR011-vcMMAE induced regression of established human SK-MEL-2 and SK-MEL-5 xenografts at doses from 1.25 to 80 mg/kg treatment when administered intravenously every 4 days (4 treatments); strikingly, regressions were not associated with re-growth during the observation period (200 days). The disappearance rate of implants was dose dependent (minimum time, 18.5 days). Detectable serum CR011-vcMMAE >or=1 microg/mL (approximately 0.01 microM) was observed for >30 days post-dose; CR011-vcMMAE showed an elimination half-life of 10.3 days. A low volume of distribution suggested that CR011-vcMMAE was confined to blood and interstitial fluid. CR011-vcMMAE could be delivered by either a single bolus dose or by intermittent dosing (i.e., every 1, 2, 4, 8, or 16 days) with no discernible differences in the proportion of tumor-free survivors, indicating a lack of schedule dependency. The antibody-drug conjugate produced complete regressions, but the equivalent doses of free monomethylauristatin E or unconjugated antibody did not show anti-tumor effects. In addition, decreases in plasma tumor-derived human interleukin-8 coincided with tumor nodule disappearance. CONCLUSIONS: Short-term anti-tumor effects and long-term effects (complete regression) were observed with CR011-vcMMAE, but not with the reference agents. These results suggest that CR011-vcMMAE may provide therapeutic benefit in malignant melanoma.


Assuntos
Imunotoxinas/uso terapêutico , Melanoma/tratamento farmacológico , Glicoproteínas de Membrana/efeitos dos fármacos , Adulto , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Melanoma/patologia , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Metástase Neoplásica/tratamento farmacológico , Transplante Heterólogo
19.
ACS Appl Mater Interfaces ; 9(3): 2541-2549, 2017 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-28032991

RESUMO

A metal organic framework (MOF), synthesized from cobalt salt, melamine (mela), and 1,4-dicarboxybezene (BDC), was used as precursor to prepare Co/CoNx/N-CNT/C electrocatalyst via heat treatment at different temperature (700-900 °C) under nitrogen atmosphere. Crystallites size and microstrain in the 800 °C heat-treated sample (MOFs-800) were the lowest, whereas the stacking fault value was the highest among the rest of the homemade samples, as attested to by the Williamson-Hall analysis, hence assessing that the structural or/and surface modification of Co nanoparticles (NPs), found in MOFs-800, was different from that in other samples. CNTs in MOFs-800, interacting with Co NPs, were formed on the surface of the support, keeping the hexagonal shape of the initial MOF. Among the three homemade samples, the MOF-800 sample, with the best electrocatalytic performance toward oxygen reduction reaction (ORR) in 0.1 M KOH solution, showed the highest density of CNTs skin on the support, the lowest ID/IG ratio, and the largest N atomic content in form of pyridinic-N, CoNx, pyrrolic-N, graphitic-N, and oxidized-N species. Based on the binding energy shift toward lower energies, a strong interaction between the active site and the support was identified for MOFs-800 sample. The number of electron transfer was 3.8 on MOFs-800, close to the value of 4.0 determined on the Pt/C benchmark, thus implying a fast and efficient multielectron reduction of molecular oxygen on CoNx active sites. In addition, the chronoamperometric response within 24 000 s showed a more stable current density at 0.69 V/RHE on MOFs-800 as compared with that of Pt/C.

20.
Antibodies (Basel) ; 6(4)2017 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31548535

RESUMO

Thiosuccinimide-linked antibody-drug conjugates (ADCs) are susceptible to drug loss over time due to a retro-Michael reaction, which can be prevented by selecting stable conjugation positions or hydrolysis of the thiosuccinimide. Here, we investigate pyrrolobenzodiazepine (PBD) ADC drug-linkers equipped with N-phenyl maleimide functionality for stable thiol conjugation via thiosuccinimide hydrolysis. Two PBD drug-linker formats (enzyme-cleavable and non-cleavable) were evaluated following site-specific conjugation to an engineered cysteine incorporated at position T289, which is known to be unstable for N-alkyl maleimide conjugates. N-phenyl maleimide PBDs conjugated to antibodies with similar efficiencies as N-alkyl maleimide PBDs and enhanced thiosuccinimide hydrolysis for N-phenyl maleimide PBDs was confirmed by mass spectrometry, capillary isoelectric focusing, and a SYPRO Orange dye binding assay. All of the PBD ADCs were highly potent in vitro regardless of maleimide- or linker-type, exhibiting low pM EC50 values. Thiol conjugation to N-phenyl maleimide PBD minimized the retro-Michael reaction in both rat and mouse serum. However, cleavage of the valine-alanine dipeptide in mouse serum for ADCs containing cleavable drug-linker led to drug loss regardless of maleimide type, which impacted ADC potency in tumor growth inhibition studies that were conducted in mouse models. Therapeutic improvement in mouse tumor models was realized for ADCs prepared with non-cleavable PBD drug-linkers that were conjugated through N-phenyl maleimide, where a stronger tumor growth inhibition (TGI) response was achieved when compared to the analogous N-alkyl maleimide drug-linker ADC. Altogether, our findings highlight the stability and efficacy benefits of N-phenyl maleimide functionality for ADCs that are produced with thiol-maleimide conjugation chemistry.

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