ASPIRIN AND ASPIRIN-LIKE DRUGS INDUCE HLA-DR EXPRESSION IN HT29 COLON-CANCER CELLS

Nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the incidence o f colon cancer. The underexpression of HLA antigens during colon cance r development is suspected to be a mechanism by which malignant cells escape immune surveillance. We examined whether NSAIDs affect the expr ession of HLA-DR in HT29 human colon adenocarcinoma cells, which do no t express HLA-DR. Aspirin, indomethacin and sulindac induced several-f old the expression of HLA-DR in these cells in a concentration- and ti me-dependent manner. Aspirin increased HLA-DR alpha steady-state mRNA levels and HLA-DR alpha gene transcription rate. These findings raise the possibility that such a mechanism may be operative in vivo.