Abstract
We investigated the kinetics, cellular uptake and intracellular distribution of 99mTc-tetrofosmin in tumor cell lines and compared them with those of 99mTc-MIBI and 201Tl. Methods: At specific intervals after incubation with radiotracers, cellular uptake was determined. Cells were also treated with nigericin, carbonyl cyanide m-chlorophenylhydrazone (CCCP) and ouabain to determine their effects on the uptake of the tracers. Results: Each tracer showed similar uptake kinetics in both cell lines, and a steady-state was maintained for at least 4 hr. Nigericin stimulated the uptake of both 99mTc-tetrofosmin and 99mTc-MIBI in HBL-2 cells, although it inhibited their uptake in SW-13 cells. Nigericin also inhibited 90% of 201Tl uptake in both cell lines. Addition of CCCP caused 73%-97% release of accumulated 99mTc-MIBI from both cell lines with or without nigericin pretreatment, indicating that most of the accumulated 99mTc- MIBI was related to mitochondria. The effect of CCCP on accumulated 99mTc- tatrofosmin was less marked than that on 99mTc-MIBI in both cell lines, indicating that only a part of accumulated 99mTc-tetrofosmin, was related to mitochondria. Ouabain preincubation inhibited 74%-77% and 51%-53% of 201Tl uptake in HBL-2 and SW-13 cells, respectively, as well as inhibited 22%-31% uptake of 99mTc-tetrofosmin in both HBL-2 and SW-13 cells. Uptake by the dead ceils of either cell line was negligible for each tracer. Conclusion: Technetium-99m-tetrofosmin uptake depends on both cell membrane and mitochondrial potentials. Only a small fraction of 99mTc-tetrofosmin accumulates inside the mitochondria, while most 99mTc-MIBI accumulates inside the mitochondria. Thallium-201 uptake is partly independent of the Na+, K+ pump.
Original language | English (US) |
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Pages (from-to) | 1551-1556 |
Number of pages | 6 |
Journal | Journal of Nuclear Medicine |
Volume | 37 |
Issue number | 9 |
State | Published - Sep 1 1996 |
Externally published | Yes |
Keywords
- mitochondrial and cell membrane potentials
- technetium-99m- MIBI
- technetium-99m-tetrofosmin
- thallium-201
- tumor cell lines
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging