Comparison of the uptake and clearance of Tc-99m MIBI, TI-201 and Ga-67 indrug-resistant lymphoma cell lines

Tc-99m sestamibi (MIBI) has been used as a tumor-seeking agent. However, it s role in detecting lymphomas has not been widely investigated. The aim of the present study was to determine the uptake and clearance characteristics of Tc-99m MIBI in vincristine-resistant lymphoma cell lines. In addition, thallium-201 (TI-201) and gallium-67 (Ga-67) uptake and clearance character istics were evaluated for comparison with Tc-99m MIBI. Drug-resistant lymph oma cell lines (monocyte-like, histiocytic lymphoma. human; B-lymphoma cell line, American Burkitt lymphoma, lymphoblastoid. human; Hodgkin's disease, lymphoid, human) were selected by multistep vincristine treatment up to 50 nM. After incubation of the radiotracers, Tc-99m MIBI,TI-201 and Ga-67, in medium for 0, 10, 20, 30, 60 or 120 min, the uptake and clearance of each radiotracer were measured in the drug-resistant lymphoma cell lines. In add ition, P-glycoprotein expression was determined by immunohistochemical stud y. In a comparison of the three radiotracers, the uptake of Tc-99m MIBI was the greatest in the studied wild-type lymphoma cell lines. Tc-99m MIBI upt ake was much lower in drug-resistant tumor cell lines than in non-resistant cell lines. On the other hand, the uptake characteristics of TI-201 did no t differ between drug-resistant and non-resistant cells. Immunohistochemist ry analyses of Ab-1 or JSB indicated that tumor cells expressed MDR-1 prote in in all three cell lines. Tc-99m MIBI is a good radiotracer for detecting drug resistance in lymphoma cell lines. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.