방사선의학 웹진

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Abstract
Malignant melanoma is a highly aggressive skin cancer with increasing prevalence worldwide. The 5-year survival rate for localized malignant melanoma is 90%, but this drops to 6% if metastasis has occurred at diagnosis. Current positron emission tomography (PET) imaging probes, such as 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG), show low sensitivity for metastatic melanoma, underscoring the need for new probes. This study explores the potential of 68Ga-labeled 2,2',2″,2‴-(2-(4-(3-(2-((2-(5-iodopicolinamido)ethyl)(methyl)amino)ethyl)thioureido)benzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (68Ga-MI-0202F1) as a novel PET imaging probe designed for enhanced specificity and sensitivity towards melanin. The precursor MI-0202F1 was synthesized from 5-iodopicolinic acid, 2,2'-diamino-N-methyldiethylamine, and 2,2',2″,2‴-(2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid ((p-SCN-Bn)-DOTA). The precursor was labeled with 68Ga in a reaction vial at 95°C and pH 5.0 for 10 min. The radiochemical purity of the 68Ga-labeled compound was determined using radio-thin-layer chromatography. Cellular uptake of the iodinated benzamide derivative was evaluated in the B16F10 cell line (mouse melanoma) following L-tyrosine treatment. MicroPET studies were conducted at 30 and 60 min post-intravenous injection of the labeled complex into B16F10 tumor-bearing mice. The non-decay-corrected radiochemical yield was 95.96 ± 3.73% (n = 3), and the radiochemical purity exceeded 98%. In vitro studies demonstrated significantly higher uptake of 68Ga-MI-0202F1 in L-tyrosine-treated B16F10 cells compared with untreated cells. In vivo PET imaging showed rapid accumulation and sustained retention of 68Ga-MI-0202F1 in melanoma tumors, with high tumor-to-background ratios. Overall, 68Ga-MI-0202F1 demonstrates potential as an innovative molecular imaging probe for malignant melanoma. Further studies are needed to investigate the potential of MI-0202F1 as a theranostic agent incorporating the radioisotope pairs 68Ga and 177Lu.

Affiliations

Eunsu Kim 1, Chaewon Lee 1, Yejin Seo 1, Dagyeong Hong 1, Boreum Song 1, Jiyu Kim 2, Wookyeong Jeong 2, Seong-Young Kwon 3, Dong-Yeon Kim 4, Ayoung Pyo 5
1College of Pharmacy and Research Institute of Pharmaceutical Science, Gyeongsang National University, Jinju, Republic of Korea.
2CNCure Biotech, Hwasun, Republic of Korea.
3Department of Nuclear Medicine, Chonnam National University Medical School and Hwasun Hospital, Hwasun, Republic of Korea.
4College of Pharmacy and Research Institute of Pharmaceutical Science, Gyeongsang National University, Jinju, Republic of Korea; CNCure Biotech, Hwasun, Republic of Korea. Electronic address: dykim@gnu.ac.kr.
5College of Pharmacy and Research Institute of Pharmaceutical Science, Gyeongsang National University, Jinju, Republic of Korea. Electronic address: payjal@gnu.ac.kr.