RESUMEN
Immunotoxins are chimeric molecules, which combine antibody specificity to recognize and bind with high-affinity tumor-associated antigens (TAA) with the potency of the enzymatic activity of a toxin, in order to induce the death of target cells. Current immunotoxins present some limitations for cancer therapy, driving the need to develop new prototypes with optimized properties. Herein we describe the production, purification and characterization of two new immunotoxins based on the gene fusion of the anti-carcinoembryonic antigen (CEA) single-chain variable fragment (scFv) antibody MFE23 to α-sarcin, a potent fungal ribotoxin. One construct corresponds to a conventional monomeric single-chain immunotoxin design (IMTXCEAαS), while the other one takes advantage of the trimerbody technology and exhibits a novel trimeric format (IMTXTRICEAαS) with enhanced properties compared with their monomeric counterparts, including size, functional affinity and biodistribution, which endow them with an improved tumor targeting capacity. Our results show the highly specific cytotoxic activity of both immunotoxins in vitro, which was enhanced in the trimeric format compared to the monomeric version. Moreover, the trimeric immunotoxin also exhibited superior antitumor activity in vivo in mice bearing human colorectal cancer xenografts. Therefore, trimeric immunotoxins represent a further step in the development of next-generation therapeutic immunotoxins.
Asunto(s)
Antineoplásicos Inmunológicos/farmacología , Antígeno Carcinoembrionario/genética , Neoplasias Colorrectales/terapia , Endorribonucleasas/química , Proteínas Fúngicas/química , Inmunotoxinas/farmacología , Proteínas Recombinantes de Fusión/farmacología , Animales , Antineoplásicos Inmunológicos/química , Antineoplásicos Inmunológicos/inmunología , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/inmunología , Antígeno Carcinoembrionario/inmunología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/inmunología , Neoplasias Colorrectales/mortalidad , Endorribonucleasas/genética , Endorribonucleasas/inmunología , Proteínas Fúngicas/genética , Proteínas Fúngicas/inmunología , Expresión Génica , Humanos , Inmunotoxinas/química , Inmunotoxinas/genética , Masculino , Ratones , Ratones Desnudos , Pichia/genética , Pichia/metabolismo , Plásmidos/química , Plásmidos/metabolismo , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Anticuerpos de Cadena Única/química , Anticuerpos de Cadena Única/genética , Anticuerpos de Cadena Única/inmunología , Análisis de Supervivencia , Carga Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The effect of isoflurane on intraventricular pressure (IVP) was examined during nitrous oxide with fentanyl anaesthesia in patients undergoing craniotomy during normocapnia or hypocapnia. Hypocapnic patients (n = 30, PaCO2 3.3 (0.1) kPa) were allocated to three groups (A, B, C; n = 10 each) according to the inspired concentration of isoflurane (1%, 1.5%, 2%). Normocapnic patients (n = 10, PaCO2 4.7 (0.1) kPa) received an inspired concentration of 1% isoflurane (group D). In patients in groups C and D, IVP increased significantly in response to isoflurane (P less than 0.01). In groups A and B, IVP did not change significantly (P greater than 0.05). Mean arterial pressure and cerebral perfusion pressure decreased significantly (P less than 0.001) in all groups in response to isoflurane.