Evaluation of 188Re-DTPA-deoxyglucose as a potential cancer radiopharmaceutical

We aimed to synthesize diethylenetriamine pentaacetic acid-deoxyglucose (DTPA-DG) radiolabeled with (188)Re and to evaluate its biologic characteristics using mammary tumor-bearing mice.

The biodistribution of the radiolabeled compound was determined by tissue counting at 3, 12, and 24 hours after injection in experimental animals. Scintigraphic examinations of nude mice bearing breast cancer (MCF-7 cells) were performed after (188)Re-DTPA-DG (18.5 MBq) was injected in the tail vein. For the tumor inhibitory portion of this work, tumor volumes were measured and recorded every 3 days until the 21st day after injection.

The radiochemical purity of (188)Re-DTPA-DG was 95.0%. Based on biodistribution measurements, (188)Re-DTPA-DG was taken up at high levels by the tumor. The mean tumoral percent injected dosages per gram (% ID/g) were 1.98 +/- 0.29 (SD), 2.89 +/- 0.43, and 0.42 +/- 0.06 % ID/g at 3, 12, and 24 hours, respectively, after injection. In the (188)Re-DTPA-DG scintigraphic examinations, the tumors were clearly delineated on the images recorded 2, 4, 8, 12, and 24 hours after injection. In the tumor inhibitory evaluations, the tumor volume of the (188)Re-DTPA-DG-treated group increased more slowly than that of the control groups, which were treated with (188)Re-perrhenate or saline (p < 0.01). Rhenium-188-DTPA-DG showed excellent tumor targeting and tumor growth suppression properties on MCF-7 tumor cells.

Rhenium-188-DTPA-DG may be a potential agent for the diagnosis and radiotherapy of tumors.