The 68Ga-labeled chlorinated benzamide derivative: A novel PET imaging probe for detection of melanoma

The benzamide structure is known for its ability to target melanin, a specific biomarker of melanoma. Therefore, we developed a new chlorinated benzamide structure for the detection of melanoma on positron emission tomography (PET). The derived benzamide structure was combined with a specific amine structure and labeled with the radioactive isotope 68 Ga by incorporating the chelator p -SCN-Bn-DOTA (2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) for PET imaging. In vitro uptake was measured in the B16F10 mouse melanoma cell line, and in vivo studies were performed with B16F10-bearing mice. The radiochemical yield of chlorinated benzamide derivative was over 95 % ( n > 3) at 90 °C for 10 min at pH 5.5, and the radiochemical purity exceeded 98 %. Cell uptake of labeled compound was significantly higher in melanin-expressing cells than in non-melanin-expressing cells. Furthermore, this compound successfully imaged B16F10 xenografts on microPET imaging. The chlorinated benzamide derivative successfully chelated 68 Ga and specifically imaged melanoma and may therefore have potential as an imaging agent for malignant melanoma with melanin overexpression. • The 68 Ga-labeled chlorinated benzamide derivative ( 68 Ga-MI-0202D1) was synthesized for the detection of melanoma using positron emission tomography (PET). • The 68 Ga-MI-0202D1 was evaluated in vitro and in vivo . • The 68 Ga-MI-0202D1 showed specific uptake in the melanin-activated mouse melanoma cell line (B16F10). • The 68 Ga-MI-0202D1 visualized melanoma specifically using PET in a mouse bearing B16F10 tumors at 30 and 60 min after i.v . injection. • The 68 Ga-MI-0202D1 would have the potential as a PET probe to detect melanoma.