DOWN-MODULATION OF HLA CLASS-I EXPRESSION BY DEXAMETHASONE IN MCF-7 CELL-LINE

Several reports have shown the importance of MHC class I antigens in e nabling the host to regulate tumour growth in vivo. Glucocorticoid hor mones have strong immunosuppressive effects and are known to be regula tors of gene transcription. In this report the expression of Major His tocompatibility Complex (MHC) class I antigens in six breast carcinoma cell lines have been studied before and after treatment with the synt hetic glucocorticoid dexamethasone. Hence, HLA class I expression in t he MCF-7 cell line was down-regulated in tie presence of dexamethasone . This down-modulation of expression appeared to be mediated by transc riptional mechanisms, as revealed by HLA-class I mRNA levels.