Fig 2: Expression levels of HMB-45, CCKAR, and CCK in clinical melanoma and A375 human melanoma cells. Data of (a) clinical melanoma and (b) A375 cells were obtained from GSE8401 and GSE7929, respectively. (b) Poorly metastatic A375 parents were intravenously injected into nude mice, and highly metastatic derivatives were obtained from the lung. The data were expressed as the mean ± SEM. P-values were calculated by two-tailed t-test. ∗∗P < 0.01. CCK, cholecystokinin; CCKAR, cholecystokinin A receptor;

Fig 3: Expression levels of CCK receptors and CCK in melanoma and SCC cells. (a) Flow cytometric analysis of CCK receptors in melanoma and SCC cells. B16-F1, A375, A431, and HSC-1 cells were stained with the anti-CCKAR antibody (red line, upper panel), anti-CCKBR antibody (red line, lower panel), isotype control antibody (black dashed line), or second antibody only (filled gray). NHEKs and Jurkat cells were used as positive controls for CCKAR and CCKBR, respectively. (b, c) RT-PCR analysis of mRNA for mouse CCK and ß-actin and (b) for human CCK and (c) ß-actin. Product length was as follows: 224 bp for mouse CCK, 163 bp for mouse ß-actin, 389 bp for human CCK, and 305 bp for human ß-actin. Data are representative of two independent experiments. CCK, cholecystokinin; CCKAR, cholecystokinin A receptor; CCKBR, cholecystokinin B receptor; NHEK, normal human epidermal keratinocyte; SCC, squamous cell carcinoma.

Fig 4: CCKAR is expressed in melanoma cells. (a, b) Immunohistochemical images of SSM, AM, PN, and BN stained with the anti-CCKAR, anti-CCK, rabbit IgG isotype control, anti‒HMB-45, anti‒Melan A, and mouse IgG1 isotype control mAb. Positive staining (red) for CCKAR and CCK in tumor cells indicated by black arrowheads is shown in the inserts at high magnification. Red arrowheads indicate positive staining with HMB-45 and Melan A in BN, as shown in the inserts at high magnification. The images are representative of five SSM, five AM, four PN, and three BN cases. Bar = 40 and 20 μm for the inserts. AM, acral melanoma; BN, blue nevus; CCK, cholecystokinin; CCKAR, CCK receptor A; PN, pigmented nevus; SSM, superficial spreading melanoma.