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

Abstract

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 Ga-68 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 degrees 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 Ga-68 and specifically imaged melanoma and may therefore have potential as an imaging agent for malignant melanoma with melanin overexpression.