Effects of mitomycin C and carboplatin pretreatment on multidrug resistance-associated P-glycoprotein expression and on subsequent suppression of tumor growth by doxorubicin and paclitaxel in human metastatic breast cancer xenografted nude mice.
Oncol Res
; 11(7): 303-10, 1999.
Article
en En
| MEDLINE
| ID: mdl-10757444
Overexpression of P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP), and several other proteins has been associated with development of multidrug resistance by cancer cells, which represents a significant obstacle to successful treatment by chemotherapy. We had previously demonstrated that a single noncytotoxic dose of mitomycin C (MMC), carboplatin, or one of several other DNA cross-linking agents suppressed mRNA expression of the mdr1 gene coding for Pgp, leading to a subsequent suppression of Pgp protein levels and a concomitant decrease in drug efflux. Pretreatment with MMC led to a 5- to 10-fold decrease in the ED50 for cell killing by a subsequent agent such as the Pgp substrate, doxorubicin, but did not affect killing by the non-Pgp substrate, cisplatin. In this study, we report that MMC and carboplatin each significantly suppressed Pgp protein levels in human MDA-MB-435 cells xenografted as solid tumors into the lateral mammary fat pads of female nude mice, with a similar time course as had previously been observed in cell culture. Pretreatment of mice with MMC or carboplatin 48-72 h prior to receiving either doxorubicin or paclitaxel caused a significantly greater reduction in tumor growth rate compared to either agent alone or the combination given simultaneously. These data suggest that a combination chemotherapy regimen consisting of a DNA cross-linking agent given to modulate the MDR phenotype, followed by a second cytotoxic agent, may be an effective treatment for human patients with de novo or late stage acquired multidrug-resistant malignancies.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias de la Mama
/
Protocolos de Quimioterapia Combinada Antineoplásica
/
Carboplatino
/
Mitomicina
/
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP
/
Resistencia a Múltiples Medicamentos
/
Proteínas de Neoplasias
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
/
Female
/
Humans
Idioma:
En
Revista:
Oncol Res
Asunto de la revista:
NEOPLASIAS
Año:
1999
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos