RESUMO
The purpose of this study was to investigate the antitumor effects of a combination of metronomic doses of a novel delivery vehicle, PLGA-PRINT nanoparticles containing docetaxel, and antiangiogenic mEZH2 siRNA incorporated into chitosan nanoparticles. In vivo dose-finding studies and therapeutic experiments were conducted in well-established orthotopic mouse models of epithelial ovarian cancer. Antitumor effects were determined on the basis of reduction in mean tumor weight and number of metastatic tumor nodules in the animals. The tumor tissues from these in vivo studies were stained to evaluate the proliferation index (Ki67), apoptosis index (cleaved caspase 3), and microvessel density (CD31). The lowest dose of metronomic regimen (0.5 mg/kg) resulted in significant reduction in tumor growth. The combination of PLGA-PRINT-docetaxel and CH-mEZH2 siRNA showed significant antitumor effects in the HeyA8 and SKOV3ip1 tumor models (P < 0.05). Individual as well as combination therapies showed significant antiangiogenic, antiproliferative, and proapoptotic effects, and combination therapy had additive effects. Metronomic delivery of PLGA-PRINT-docetaxel combined with CH-mEZH2 siRNA has significant antitumor activity in preclinical models of ovarian cancer.
Assuntos
Antineoplásicos/administração & dosagem , Nanopartículas/administração & dosagem , Neoplasias Ovarianas/tratamento farmacológico , Complexo Repressor Polycomb 2/antagonistas & inibidores , Complexo Repressor Polycomb 2/genética , RNA Interferente Pequeno/administração & dosagem , Taxoides/administração & dosagem , Administração Metronômica , Animais , Antineoplásicos/química , Linhagem Celular Tumoral , Docetaxel , Proteína Potenciadora do Homólogo 2 de Zeste , Feminino , Inativação Gênica/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Nanopartículas/química , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Complexo Repressor Polycomb 2/metabolismo , RNA Interferente Pequeno/genética , Ensaios Clínicos Controlados Aleatórios como Assunto , Taxoides/químicaRESUMO
Four sites of the non-homologous region (coding amino acid residues of 347, 421, 466 and 533) of a gene were randomly selected for splitting to investigate the function of beta-glucosidase from Agrobacterium tumefaciens in the co-refolding of peptides into the catalytically active enzyme. As a result of gene splitting, four N- and C-terminal domain peptides were obtained as insoluble inclusion bodies. No catalytic activity was observed when these fragments refolded individually. However, a considerable amount of activity was restored when the two fragments derived from N- and C- terminal peptides were co-refolded together. The deletion of amino acid residues in the non-homologous region resulted in a complete loss of enzyme activity, which suggests that truncation of amino acids in this region strongly affects the co-refolding ability of the enzyme to maintain activity.
Assuntos
Agrobacterium tumefaciens/enzimologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Dobramento de Proteína , beta-Glucosidase/química , beta-Glucosidase/metabolismo , Álcoois/farmacologia , Catálise , Estabilidade Enzimática/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Cinética , Peso Molecular , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/isolamento & purificação , Plasmídeos/genética , Conformação Proteica/efeitos dos fármacos , Desnaturação Proteica/efeitos dos fármacos , Renaturação Proteica/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Especificidade por Substrato , Temperatura , beta-Glucosidase/genéticaRESUMO
A family 2b carbohydrate-binding module from Streptomyces thermoviolaceus STX-II was fused at the carboxyl-terminus of XynB, a thermostable and single domain family 10 xylanase from Thermotoga maritima, to create a chimeric xylanase. The chimeric enzyme (XynB-CBM2b) was purified and characterized. It displayed a pH-activity profile similar to that of XynB and was stable up to 90 degrees C. XynB-CBM2b bound to insoluble birchwood and oatspelt xylan. Whereas its hydrolytic activities toward insoluble xylan and p-nitrophenyl-beta-xylopyranoside were similar to those of XynB, its activity toward soluble xylan was moderately higher than that of XynB.