Evaluation of 188 Re-DTPA-Deoxyglucose as a Potential Cancer Radiopharmaceutical

Synthesis and preliminary evaluation of a 99mTc labelled deoxyglucose complex {[99mTc]DTPA-bis(DG)} as a potential SPECT based probe for tumor imaging

[^99mTc]DTPA-bis(DG): a potent tumor imaging probe.

Preliminary Studies of 177Lu-Diethylenetriamine Penta-Acetic Acid-Deoxyglucose in Hepatic Tumor-Bearing Mice

Objective: The purpose of this study was to explore the potential use of ¹⁷⁷Lu-diethylenetriamine penta-acetic acid-deoxyglucose (¹⁷⁷Lu-DTPA-DG) as a radiopharmaceutical for hepatic tumor treatment. Methods: Lutetium-177 (¹⁷⁷Lu) was labeled with DTPA-DG by adding 2 mCi ¹⁷⁷LuCl₃ to 0.05 mg DTPA-DG (pH 5-6) at room temperature for 1 h. The quality of the¹⁷⁷Lu-DTPA-DG solutions was determined by thin-layer chromatography and high-performance liquid chromatography. Cellular uptake studies with ¹⁸F-fluorodeoxyglucose (FDG), ¹⁷⁷Lu-DTPA-DG and ¹⁷⁷Lu-DTPA and a blocking study with 1.0 mg d-glucose were performed. Biodistribution, imaging, and radiotherapy studies of ¹⁷⁷Lu-DTPA-DG were performed with the SMMC-7721 model. Results: ¹⁷⁷Lu-DTPA-DG had a high radiochemical purity (>97%). The cellular uptake of ¹⁷⁷Lu-DTPA-DG was much higher than that of the ¹⁷⁷Lu-DTPA. The biodistribution of ¹⁷⁷Lu-DTPA-DG demonstrated that the complex accumulated in the tumor with high tumor/blood and tumor/muscle ratios. The tumors in mice in the ¹⁷⁷Lu-DTPA-DG group clearly displayed the high uptake of ¹⁷⁷Lu-DTPA-DG. After radiotherapy with ¹⁷⁷Lu-DTPA-DG, tumor growth decreased, and the overall survival was longer than that in the ¹⁷⁷LuCl₃ group (268.58 ± 17.96 mm³ vs. 507.43 ± 55.72 mm³, p = 0.002) and the normal saline group (268.58 ± 17.96 mm³ vs. 483.68 ± 27.51 mm³, p < 0.05). Conclusions: This preliminary study suggests that ¹⁷⁷Lu-DTPA-DG has the potential to become a liver radiopharmaceutical agent and should be further investigated.

Therapeutic and scintigraphic applications of polymeric micelles: combination of chemotherapy and radiotherapy in hepatocellular carcinoma

This study evaluated a multifunctional micelle simultaneously loaded with doxorubicin (Dox) and labeled with radionuclide rhenium-188 ((188)Re) as a combined radiotherapy and chemotherapy treatment for hepatocellular carcinoma. We investigated the single photon emission computed tomography, biodistribution, antitumor efficacy, and pathology of (188)Re-Dox micelles in a murine orthotopic luciferase-transfected BNL tumor cells hepatocellular carcinoma model. The single photon emission computed tomography and computed tomography images showed high radioactivity in the liver and tumor, which was in agreement with the biodistribution measured by γ-counting. In vivo bioluminescence images showed the smallest size tumor (P<0.05) in mice treated with the combined micelles throughout the experimental period. In addition, the combined (188)Re-Dox micelles group had significantly longer survival compared with the control, (188)ReO4 alone (P<0.005), and Dox micelles alone (P<0.01) groups. Pathohistological analysis revealed that tumors treated with (188)Re-Dox micelles had more necrotic features and decreased cell proliferation. Therefore, (188)Re-Dox micelles may enable combined radiotherapy and chemotherapy to maximize the effectiveness of treatment for hepatocellular carcinoma.

Multimodal image-guided photothermal therapy mediated by 188Re-labeled micelles containing a cyanine-type photosensitizer

Multifunctional micelles loaded with the near-infrared (NIR) dye and labeled with the radionuclide rhenium-188 ((188)Re) have been developed to provide multimodalities for NIR fluorescence and nuclear imaging and for photothermal therapy (PTT) of cancer. The NIR dye, IR-780 iodide, allowed the micelles to have dual functions in cancer NIR imaging and PTT. The (188)Re-labeled IR-780 micelles enabled imaging by NIR fluorescence and by microSPECT to guide the delivery of drugs and to monitor in real-time the tumor accumulation, intratumoral distribution, and kinetics of drug release, which serve as a basis of specific photothermal injury to the targeted tissue. We also investigated the biodistribution, generation of heat, and photothermal cancer ablation of IR-780 micelles of both in vitro and in vivo xenografts. Histopathology observed irreversible tissue damage, such as necrotic features, decreased cell proliferation, increased apoptosis of cells, and increased expression of heat shock proteins in the PTT-treated tumors. The (188)Re-labeled IR-780 micelles offer multifunctional modalities for NIR fluorescence and nuclear imaging and for PTT of cancer.