Assuntos
Humanos , Masculino , Feminino , Instilação de Medicamentos , Analgesia Interpleural , Empiema Pleural/tratamento farmacológico , Desoxirribonucleases/uso terapêutico , Empiema Pleural/fisiopatologia , Empiema Pleural/terapia , Desoxirribonucleases/metabolismo , Desoxirribonucleases/farmacologia , Desoxirribonucleases/farmacocinética , /tendênciasRESUMO
The chemical nuclease metalloporphyrin (manganese(III) porphyrin) can cleave DNA irreversibly and can thus constitute a potential antitumor drug. However, these molecules show low permeability to cell surface membranes. We report here the conjugation of an amphipathic carrier peptide to improve considerably its cellular delivery. The metalloporphyrin-peptide conjugate can be internalized by cells within only 5 min of incubation with a yield as high as 80%. Furthermore, the metalloporphyrin-peptide conjugate is able to cleave in vitro high or low molecular weight DNA to the same extend as metalloporphyrin alone without affecting the sequence-specific cleaving activity of the porphyrin. The conjugate is 100-fold more efficient at inducing tumor cells death than the free metalloporphyrin via a mechanism involving genomic DNA cleavage. The results are promising for further therapeutic applications with antitumor drugs such as metalloporphyrin, and also with other existing drugs by using a carrier peptide system in order to improve the cellular uptake of such molecules.
Assuntos
Antineoplásicos/farmacocinética , Metaloporfirinas/farmacocinética , Peptídeos/farmacocinética , Sequência de Aminoácidos , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Sítios de Ligação , Divisão Celular/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , DNA de Neoplasias/metabolismo , Desoxirribonucleases/química , Desoxirribonucleases/farmacocinética , Desoxirribonucleases/farmacologia , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Humanos , Metaloporfirinas/química , Metaloporfirinas/farmacologia , Camundongos , Dados de Sequência Molecular , Peptídeos/química , Especificidade por Substrato , Tensoativos/química , Tensoativos/farmacocinética , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
Preclinical pharmacokinetic studies with recombinant human DNase (rhDNase) following a single intravenous injection of 0.01, 0.1, or 1.0 mg/kg in male rats demonstrated that clearance and steady-state volume of distribution increased at the 1.0 mg/kg dose, whereas the mean exit time from the serum remained unchanged. To characterize the molecular form of 125I-rhDNase in serum, rats were intravenously injected with approximately 300 microCi (5 micrograms)/kg 125I-rhDNase or approximately 300 microCi (5 micrograms)/kg 125I-rhDNase with 1 mg/kg unlabeled rhDNase, and blood samples were taken at 2 min. Urine was collected from one rat in each group from 0-6 and 6-24 hr after injection. Serum samples were analyzed by trichloroacetic acid precipitation and native PAGE; urine samples were analyzed by size exclusion HPLC. Native PAGE results indicate that there is a protein present in the serum that binds rhDNase specifically. The presence of excess unlabeled rhDNase decreases the 125I-rhDNase-binding protein complex level relative to free 125I-rhDNase. In contrast, a high-molecular weight peak of radioactivity was seen after size exclusion HPLC of the urine from the animal that received 125I-rhDNase with unlabeled rhDNase rather than the animal that received 125I-rhDNase alone. In addition to its effects on disposition, a specific serum binding protein for rhDNase may play a role in modulating the bioactivity of circulating rhDNase.
