Reduced HLA-A,B,C expression in tumourigenic v-raf transfected human urothelial cells.

Tumourigenic (TGrIII) human urothelial cells grown in vitro have previously been demonstrated to have a markedly decreased expression of beta 2-microglobulin and HLA-A,B,C antigens as compared to non-tumourigenic (TGrII) human urothelial cell lines. Furthermore, during 'spontaneous' in vitro transformation of a non-tumourigenic (TGrII) human urothelial cell line Hu609 into a tumourigenic (TGrIII) subline Hu609T/LLH, changes in morphology and tumourigenicity have been demonstrated to be accompanied by a decreased HLA-A,B,C expression. After malignant transformation of the non-tumourigenic (TGrII) human urothelial cell line HCV29 by DNA transfection with the v-raf oncogene, four sublines could be isolated. In this study we have investigated these sublines for their expression of membrane bound HLA-A,B,C antigens and provide further evidence that an inverse relationship exists between tumourigenicity and monomorphic HLA-A,B,C expression. Treatment of the cells with recombinant human interferon alpha for 3 days increased the expression of HLA-A,B,C antigens by 50-150% indicating that at least some of the reduced HLA-A,B,C expression could be due to decreased synthesis of HLA-A,B,C antigens. All the transfected cell lines overexpress v-raf and c-myc.