hMAGE-A1 overexpression reduces TNF-alpha cytotoxicity in ME-180 cells.

Melanoma antigen (MAGE) belongs to a large family of tumor-associated antigens that are expressed in tumors, but not in normal adult tissues with the exception of a few normal cell types. However, its cellular function has not been characterized. In this study, we screened tumor cell lines for the hMAGE-A1, -A2, and -A3 gene expressions by reverse transcription-polymerase chain reaction, then examined the sensitivity of the cell lines to TNF cytotoxicity. Cell lines, which express at least one of the three hMAGE-A genes, were more resistant to TNF cytotoxicity than cell lines that expressed none of the MAGE genes. By stably expressing hMAGE-A1 mRNA in the ME-180 line of human cervical carcinoma cells, it was possible to isolate clones in which the hMAGE-A1 is constitutively expressed. These clones displayed a diminished sensitivity to the cytotoxicity that was mediated by TNF, indicating that MAGE-A1 is a protective protein.