Figure 1.

CTLA4 is highly overexpressed in human melanoma cells. A, CTLA4 mRNA expression pattern across different types of cancer cell lines in the Cancer Cell Line Encyclopedia (CCLE) database. Sample numbers (n) are indicated in parentheses. H&L, hematopoietic and lymphoid tumor cell lines; UAT, upper aerodigestive tract tumor cell lines; CNS, central nervous system tumor cell lines. Each dot represents one tumor cell line. *p<0.05. Unpaired t-test with Welch’s correction. Y axis, RMA (Robust Multi-Array Average) was used to normalize the expression data and then converted to log₂. B, CTLA4 mRNA expression in human primary melanocytes (MC), human melanoma cells, and human primary keratinocyte (KC) was determined by qRT-PCR, and plotted relative to HEMn-LP melanocytes. Data presented as mean±SEM of three to six independent experiments. C, Total CTLA4 protein expression in fixed and permeabilized human melanocytes, melanoma cell lines, HEK293T and CTLA4-overexpressing HEK293T cells stained with either mouse anti-human CTLA4-PE (BNI3) or isotype-PE control antibody, were analyzed by flow cytometry. D, Confocal photomicrographs of CTLA4 immunostaining (green) in melanocytes, melanoma cell lines, HEK293T and CTLA4-overexpressed HEK293T cells. Blue, DAPI. Images are representative of 3–5 independent experiments. Scale bar=25μm.