Potentiation of radioresponse by polymer-drug conjugates.
J Control Release
; 74(1-3): 237-42, 2001 Jul 06.
Article
em En
| MEDLINE
| ID: mdl-11489500
ABSTRACT
Although combined chemotherapy and radiotherapy has produced significantly improved response and survival rates among cancer patients, there is still a compelling need to establish the most effective way to deliver these agents. We hypothesize that the radiosensitizing effect of a chemotherapeutic agent can be further enhanced if the drug is delivered at an optimal concentration and is maintained in the tumor for a prolonged period. Using a water-soluble poly(L-glutamic acid)-conjugated paclitaxel (PG-TXL) as a model compound, we investigated whether paclitaxel delivered by means of polymeric carrier could increase the tumor's response to radiation. Mice bearing 8-mm syngeneic ovarian carcinoma OCa-1 tumors implanted intramuscularly were treated with i.v. injected PG-TXL alone or in combination with single doses of local radiation. The enhancement factors at 24 h interval, as measured by incremental tumor growth delay compared with radiation alone, ranged from 2.48 to 4.28. The values varied as a function of radiation dose. The enhancement of radioresponse is also a function of time interval between injection of PG-TXL and tumor irradiation. The enhancement factor increased with decreasing interval, suggesting that radiation may in turn mediate the sensitivity of tumor toward PG-TXL. Thus, the mechanism of PG-TXL's radiopotentiation activity is probably multifactorial. Remarkably, while combined radiation and TXL produced additive or even sub-additive interaction when radiation preceded TXL injection, combined radiation and PG-TXL produced synergistic interaction in a mammary MCa-4 tumor model. Radiation significantly increased tumor uptake of PG-TXL, suggesting a potential role of radiation-modulated antitumor activity of polymeric drugs. Our data support a treatment strategy combining radiation and polymeric chemotherapy that may have important clinical implications in terms of scheduling and optimization of the therapeutic ratio.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Radiossensibilizantes
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Control Release
Assunto da revista:
FARMACOLOGIA
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Estados Unidos