Ultrasensitive detection of malignant melanoma using PET molecular imaging probes

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 117; no. 23; pp. 12991 - 12999
• Main Authors: Pyo, Ayoung, Kim, Dong-Yeon, Kim, Heejung, Lim, Daejin, Kwon, Seong Young, Kang, Sae-Ryung, Kim, Hyung-Seok, Bom, Hee-Seung, Min, Jung-Joon
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 09.06.2020
• Subjects: Benzamide; Biological Sciences; Diagnosis; Dosage; Fluorine isotopes; Image quality; Lymph nodes; Medical imaging; Melanoma; Metastases; Metastasis; Physical Sciences; Positron emission; Positron emission tomography; Pyridines; Radiochemistry; Retention; Skin cancer; Synthesis; Tomography; Tracers; Tumors; Xenografts; Xenotransplantation; malignant melanoma; molecular imaging; metastasis; 18F-labeled pyridine-based benzamide derivative; PET
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1922313117

Malignant melanoma has one of the highest mortality rates of any cancer because of its aggressive nature and high metastatic potential. Clinical staging of the disease at the time of diagnosis is very important for the prognosis and outcome of melanoma treatment. In this study, we designed and synthesized the 18F-labeled pyridine-based benzamide derivatives N-(2-(dimethylamino)ethyl)-5-[18F]fluoropicolinamide ([18F]DMPY2) and N-(2-(dimethylamino)ethyl)-6-[18F]fluoronicotinamide ([18F]DMPY3) to detect primary and metastatic melanoma at an early stage and evaluated their performance in this task. [18F]DMPY2 and [18F]DMPY3 were synthesized by direct radio-fluorination of the bromo precursor, and radiochemical yields were ∼15–20%. Cell uptakes of [18F]DMPY2 and [18F]DMPY3 were >103- fold and 18-fold higher, respectively, in B16F10 (mouse melanoma) cells than in negative control cells. Biodistribution studies revealed strong tumor uptake and retention of [18F]DMPY2 (24.8% injected dose per gram of tissue [ID/g] at 60 min) and [18F]DMPY3 (11.7%ID/g at 60 min) in B16F10 xenografts. MicroPET imaging of both agents demonstrated strong tumoral uptake/retention and rapid washout, resulting in excellent tumor-to-background contrast in B16F10 xenografts. In particular, [18F]DMPY2 clearly visualized almost all metastatic lesions in lung and lymph nodes, with excellent image quality. [18F] DMPY2 demonstrated a significantly higher tumor-to-liver ratio than [18F]fluorodeoxyglucose ([18F]FDG) and the previously reported benzamide tracers N-[2-(diethylamino)-ethyl]-5-[18F]fluoropicolinamide ([18F]P3BZA) and N-[2-(diethylamino)-ethyl]-4-[18F]fluorobenzamide ([18F]FBZA) in B16F10-bearing or SK-MEL-3 (human melanoma)-bearing mice. In conclusion, [18F]DMPY2 might have strong potential for the diagnosis of early stage primary and metastatic melanoma using positron emission tomography (PET).