RESUMO
Plants are known to be efficient hosts for the production of mammalian therapeutic proteins. However, plants produce complex N-glycans bearing β1,2-xylose and core α1,3-fucose residues, which are absent in mammals. The immunogenicity and allergenicity of plant-specific Nglycans is a key concern in mammalian therapy. In this study, we amplified the sequences of 2 plant-specific glycosyltransferases from Nicotiana tabacum L. cv Bright Yellow 2 (BY2), which is a well-established cell line widely used for the expression of therapeutic proteins. The expression of the endogenous xylosyltranferase (XylT) and fucosyltransferase (FucT) was downregulated by using RNA interference (RNAi) strategy. The xylosylated and core fucosylated N-glycans were significantly, but not completely, reduced in the glycoengineered lines. However, these RNAi-treated cell lines were stable and viable and did not exhibit any obvious phenotype. Therefore, this study may provide an effective and promising strategy to produce recombinant glycoproteins in BY2 cells with humanized N-glycoforms to avoid potential immunogenicity.
Assuntos
Sequência de Aminoácidos , Western Blotting , Sequência de Carboidratos , Linhagem Celular , Clonagem Molecular , DNA Complementar , Genética , Regulação para Baixo , Epitopos , Genética , Alergia e Imunologia , Fucose , Metabolismo , Fucosiltransferases , Química , Genética , Alergia e Imunologia , Glicoproteínas , Química , Genética , Alergia e Imunologia , Dados de Sequência Molecular , Pentosiltransferases , Química , Genética , Alergia e Imunologia , Polissacarídeos , Química , Alergia e Imunologia , Engenharia de Proteínas , Métodos , Interferência de RNA , Especificidade da Espécie , Nicotiana , Biologia Celular , Genética , Xilose , MetabolismoRESUMO
Objective To evaluate the efficacy and adverse effects of gefitinib in the treatment of fe- male patients with advanced adenocarcinoma of lung who had failed to previous chemotherapy.Methods These patients received 250mg of gefitinib orally,once daily until disease progression or development of intol- erable toxic reaction.They were evaluated one month after treatment and every other month thereafter.Results Among the 27 evaluable patients,there were 1 CR(3.7%),11 PR(40.8%),10 SD(37.0%)and 5 PD(18.5%). The overall response rate was 44.5%(95% CI 29%～68%);and 22 patients(81.5%)gained profit(CR+PR+ SD)from the clinical therapy(95% CI 62%～94%);the mean TTP was 7.2 months.Symptomatic improvement rate was 80.0%.The main adverse effects were mild rash and diarrhea.Conclusion gefitinib has significant efficacy in the treatment of female patients with advanced tung cancer who had failed to previous chemother- apy.Adverse effects are mild.gefitinib is a suitable therapy for these patients.