Evaluation of ^99m Tc-resveratrol as a colon cancer targeting probe

The study aimed to evaluate cancer-targeting potential of a newly synthesised radiopharmaceutical, ^99m Tc-resveratrol in vivo, using colon cancer model. Colon cancer was induced in 20 male Sprague-Dawley rats by subcutaneous administration of 1,2-dimethylhydrazine (DMH), dissolved in 1 mM EDTA-normal saline, at a dose of 30 mg/kg body weight twice a week for first 4 weeks and once a week for next 12 weeks. A control group containing normal rats was used for result comparison. Colon cancer in DMH-treated group was confirmed by gross analysis of the colon, by histopathological analysis and molecular marker study in tumour tissue. At the end of the treatment period, the animals from the two groups were used for bio-distribution evaluation of ^99m Tc-resveratrol at different time intervals. High uptake of ^99m Tc-resveratrol was recorded in rat liver, spleen and kidneys, and the ratio of colon tumour uptake to normal colon uptake in DMH-treated rats increased significantly (P ≤ 0.01) with time, to reach a maximum value at 2 h but decreased thereafter. High uptake at the tumour site as compared to normal colon tissue was observed; however, the uptake by cancer cells at the target site was limited by high reticulo-endothelial uptake and rapid metabolism.