TLR expression in human melanoma cells.

UNLABELLED

There is increasing evidence that melanoma cells express TLR2, -3, and -4. However, the expression of other TLRs by these cells still remains unknown. We investigated the expression patterns of TLR2, -3, -4, -7, -8 and -9 both on melanoma-invaded lymph nodes and on melanoma cell lines. TLR2, -3, -4, -7 and -9 mRNA expression was determined by quantitative RT-PCR. The TLR protein expression level was measured ex vivo by immunohistochemistry and in vitro by flow cytometry.

RESULTS

At the mRNA level, melanoma cells in vitro, and possibly ex vivo, expressed TLR2, -3, -4, -7 and -9. TLR2 and -4 protein expressions ex vivo were over 50%, contrasting with an absence of these 2 TLRs in vitro. On the contrary, TLR-3 and -8 proteins had a low expression ex vivo with a high expression in vitro. TLR-7 and -9 proteins were expressed ex vivo and in vitro. Our study demonstrates for the first time that melanoma cells express TLR7 and -8.