In vitro incorporation studies of 99mTc-alendronate sodium at different bone cell lines

Bisphosphonates can be labeled with Technetium-99m (99mTc) and are used for bone imaging because of their good localization in the skeleton and rapid clearance from soft tissues. Over the last decades bone scintigraphy has been used extensively in the evaluation of oncological patients to provide information about the sites of bone lesions, their prognosis and the effectiveness of therapy by showing the sequential changes in tracer uptake. Since the lesion visualization and lesion/bone ratio are important utilities for a bone scanning radiopharmaceutic; in this study incorporation of 99mTc labeled alendronate sodium (99mTc-ALD) was evaluated in U2OS (human bone osteosarcoma) and NCI-H209 (human bone carcinoma) cell lines. ALD was directly labeled by 99mTc, radiochemical purity and stability of the complex were analyzed by radioactive thin layer chromatography and radioactive high performance liquid chromatography studies. For cell incorporation study, NCI-H209 and U2OS cell lines were used with standard cell culture methods. The six well plates were used for all experiments and the integrity of each cell monolayer was checked by measuring its transepithelial electrical resistance (TEER) with an epithelial voltammeter. Results confirmed that ALD was successfully radiolabeled with 99mTc. 99mTc-ALD incorporated with NCI-H209 and U2OS cells. The uptake percentages of 99mTc-ALD in NCI-H209 and U2OS cell lines were found significantly different. Since 99mTc-ALD highly uptake in cancer cell line, the results demonstrated that radiolabeled ALD may be a promising agent for bone cancer diagnosis. (author)