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1.
EBioMedicine ; 76: 103818, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35078012

RESUMO

BACKGROUND: The emergence of new SARS-CoV-2 variants of concern B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma) and B.1.617.2 (Delta) that harbor mutations in the viral S protein raised concern about activity of current vaccines and therapeutic antibodies. Independent studies have shown that mutant variants are partially or completely resistant against some of the therapeutic antibodies authorized for emergency use. METHODS: We employed hybridoma technology, ELISA-based and cell-based S-ACE2 interaction assays combined with authentic virus neutralization assays to develop second-generation antibodies, which were specifically selected for their ability to neutralize the new variants of SARS-CoV-2. FINDINGS: AX290 and AX677, two monoclonal antibodies with non-overlapping epitopes, exhibit subnanomolar or nanomolar affinities to the receptor binding domain of the viral Spike protein carrying amino acid substitutions N501Y, N439K, E484K, K417N, and a combination N501Y/E484K/K417N found in the circulating virus variants. The antibodies showed excellent neutralization of an authentic SARS-CoV-2 virus representing strains circulating in Europe in spring 2020 and also the variants of concern B.1.1.7 (Alpha), B.1.351 (Beta) and B.1.617.2 (Delta). In addition, AX677 is able to bind Omicron Spike protein just like the wild type Spike. The combination of the two antibodies prevented the appearance of escape mutations of the authentic SARS-CoV-2 virus. Prophylactic administration of AX290 and AX677, either individually or in combination, effectively reduced viral burden and inflammation in the lungs, and prevented disease in a mouse model of SARS-CoV-2 infection. INTERPRETATION: The virus-neutralizing properties were fully reproduced in chimeric mouse-human versions of the antibodies, which may represent a promising tool for COVID-19 therapy. FUNDING: The study was funded by AXON Neuroscience SE and AXON COVIDAX a.s.


Assuntos
Anticorpos Monoclonais/imunologia , Antineoplásicos Imunológicos/imunologia , Epitopos Imunodominantes/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Anticorpos Monoclonais/uso terapêutico , Deriva e Deslocamento Antigênicos , Antineoplásicos Imunológicos/uso terapêutico , COVID-19/virologia , Modelos Animais de Doenças , Humanos , Cinética , Pulmão/patologia , Camundongos , Mutação , Testes de Neutralização , Ligação Proteica , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Tratamento Farmacológico da COVID-19
2.
Cancer Res ; 64(18): 6390-3, 2004 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-15374945

RESUMO

A new p53 family member, p73, and its isoform DeltaNp73 are increasingly recognized in cancer research as important players in tumorigenesis, as well as in chemotherapeutic drug sensitivity. Despite substantial structural similarities to p53, accumulating evidence suggests that p53 and p73 may play different roles in human tumorigenesis. In this study, we have investigated the role of p73 and DeltaNp73 in upper gastrointestinal tumorigenesis. Our results indicate that p73 and DeltaNp73 are frequently overexpressed in >60% of primary adenocarcinomas of the stomach and esophagus. We have demonstrated that this overexpression can lead to the suppression of p73 transcriptional and apoptotic activity in gastrointestinal cells. Moreover, it induces beta-catenin up-regulation and T-cell factor/lymphocyte enhancement factor-dependent transcription. Wild-type p53, but not mutant p53, can inhibit this effect. Our results demonstrate a novel mechanism for activation of beta-catenin in gastrointestinal tumors and support the concept that overexpression of p73 isoforms can play an important role in tumorigenesis.


Assuntos
Adenocarcinoma/metabolismo , Proteínas de Ligação a DNA/fisiologia , Proteínas Nucleares/fisiologia , Neoplasias Gástricas/metabolismo , Fatores de Transcrição/fisiologia , Adenocarcinoma/genética , Adenocarcinoma/patologia , Apoptose/fisiologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Proteínas do Citoesqueleto/biossíntese , Proteínas do Citoesqueleto/genética , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/patologia , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Humanos , Proteínas Nucleares/biossíntese , Proteínas Nucleares/genética , Isoformas de Proteínas , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Fatores de Transcrição TCF , Transativadores/biossíntese , Transativadores/genética , Proteína 2 Semelhante ao Fator 7 de Transcrição , Fatores de Transcrição/genética , Ativação Transcricional , Transfecção , Proteína Tumoral p73 , Proteínas Supressoras de Tumor , Regulação para Cima , beta Catenina
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