Abstract
The objective of this study was to evaluate the in vivo antitumor action of rosiglitazone (Rosi) alone or in combination with tamoxifen (Tam) on experimental mammary tumors induced by N-nitroso-N-methylurea (NMU) in Sprague-Dawley rats. Animals bearing mammary tumors were treated with 0.06 mg/kg/day or 0.12 mg/kg/day of Rosi orally, 1 mg/kg/day of Tam s.c., or with the combined treatment (Rosi+Tam). After 25 days of treatment, the following responses were observed: 45% of tumors were responsive to 0.06 mg/kg/day of Rosi treatment, while 55% of tumors under Tam treatment responded. The results of the combined Rosi+Tam treatment indicated that 75% of tumors were responsive. Similar results were obtained with 0.12 mg/kg/day of Rosi. Apoptosis, necrosis and glandular hypersecretion were observed in Rosi-treated tumors. In all cases, the combined Rosi+Tam treatment potentiated the antitumor effect of Tam alone. No side-effects were observed after treatment at any assayed dose.
Footnotes
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Abreviations: GTT, glucose tolerance test; I, insulin; IGF-I, insulin-like growth factor-I; NMU, N-nitroso-N-methylurea; Rosi, rosiglitazone; STZ, streptozotocin; Tam, tamoxifen.
- Received November 1, 2005.
- Revision received February 15, 2006.
- Accepted February 20, 2006.
- Copyright© 2006 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved
