RESUMEN
In many cancers early intervention involves surgical resection of small localised tumour masses. Inadequate resection leads to recurrence whereas overzealous treatment can lead to organ damage. This work describes production of a HER2 targeting antibody Fab fragment dual conjugated to achieve both real time near-infrared fluorescent imaging and photodynamic therapy. The use of fluorescence emission from a NIR-dye could be used to guide resection of tumour bulk, for example during endoscopic diagnosis for oesophago-gastric adenocarcinoma, this would then be followed by activation of the photodynamic therapeutic agent to destroy untreated localised areas of cancer infiltration and tumour infiltrated lymph nodes. This theranostic agent was prepared from the Fab fragment of trastuzumab initially by functional disulfide re-bridging and site-specific click reaction of a NIR-dye. This was followed by further reaction with a novel pre-activated form of the photosensitiser chlorin e6 with the exposed fragments' lysine residues. Specific binding of the theranostic agent was observed in vitro with a HER2 positive cell line and cellular near-infrared fluorescence was observed with flow cytometry. Specific photo-activity of the conjugates when exposed to laser light was observed with HER2 positive but not HER2 negative cell lines in vitro, this selectivity was not seen with the unconjugated drug. This theranostic agent demonstrates that two different photo-active functions can be coupled to the same antibody fragment with little interference to their independent activities.
Asunto(s)
Antineoplásicos Inmunológicos/farmacología , Neoplasias/tratamiento farmacológico , Fotoquimioterapia , Fármacos Fotosensibilizantes/farmacología , Receptor ErbB-2/antagonistas & inhibidores , Nanomedicina Teranóstica , Trastuzumab/farmacología , Antineoplásicos Inmunológicos/síntesis química , Antineoplásicos Inmunológicos/química , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Neoplasias/metabolismo , Neoplasias/patología , Fármacos Fotosensibilizantes/síntesis química , Fármacos Fotosensibilizantes/química , Receptor ErbB-2/metabolismo , Relación Estructura-Actividad , Trastuzumab/química , Células Tumorales CultivadasRESUMEN
Phenolic porphyrins 1, 4, and 5 form stable phenoxyl radicals 3, 6, and 7 in deoxygenated as well as oxygenated basic solutions. Mechanistic schemes are presented, involving coupled disproportionation and conproportionation reactions, that do not require oxygen involvement in the redox processes leading to phenoxyl radicals.
Asunto(s)
Fenoles/química , Porfirinas/química , Álcalis , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres , Estructura Molecular , Oxidación-Reducción , Soluciones , Espectrofotometría , Espectrofotometría UltravioletaRESUMEN
Aerial oxidation of meso-tetrakis(3,5-dimethoxy-4-hydroxyphenyl)- porphyrin 3, in the presence of the water-soluble spin trap (4-pyridyl-1-oxide)-N-t-butylnitrone (POBN), gives the porphyrin radical 4, in which spin density is localized on a phenoxyl meso-substituent. Evidence is presented to show that the spin trap inhibits solution aggregation and spin exchange of 4, but does not, as originally expected, form spin adducts with reduced-oxygen species.