Abstract
Indium-111-labeled diethylenetriamine pentaacetic acid (DTPA)-folate was evaluated as a radiopharmaceutical for targeting tumor-associated folate receptors. Methods: Athymic mice were subcutaneously inoculated with ~1.8 x 106 folate receptor-positive KB (human nasopharyngeal carcinoma) cells, yielding 0.2- to 0.6-g tumors in 15 days, at which time 111In-DTPA- folate, 111In-DTPA or 111In-citrate was administered by intravenous injection. Results: The 111In-DTPA-folate conjugate afforded marked tumor- specific 111In deposition in vive using this mouse model. The involvement of the folate receptor in mediating tumor uptake of 111In-DTPA-folate was demonstrated by the blocking of tumor uptake by coadministration of free relic acid (intravenous). The 111In-DTPA-folate also shows folate receptor-mediated uptake and retention in the kidneys, presumably reflecting radiotracer binding to folate receptors of the proximal tubules. In control experiments, the 111In-citrate radiopharmaceutical precursor was also shown to afford significant tumor uptake of 111In, but with much poorer tumor-to-background tissue contrast than that obtained with 111In-DTPA- folate. Unconjugated 111In-DTPA showed no tumor affinity. Conclusion: Indium-111-DTPA-folate appears suitable as a radiopharmaceutical for targeting tumor-associated folate receptors.
Original language | English (US) |
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Pages (from-to) | 1579-1585 |
Number of pages | 7 |
Journal | Journal of Nuclear Medicine |
Volume | 39 |
Issue number | 9 |
State | Published - Sep 1998 |
Keywords
- Folate receptor
- Indium-111-diethylenetriamine pentaacetic acid folate
- Tumor targeting
ASJC Scopus subject areas
- Radiological and Ultrasound Technology