ESTABLISHMENT AND CHARACTERIZATION OF A NEW PH(1)-POSITIVE CHRONIC MYELOID-LEUKEMIA CELL-LINE MC3 WITH TRILINEAGE PHENOTYPE AND AN ALTERED P53 GENE

A new Ph(1)-positive leukemic cell line (MC3) expressing the P210(bcr/ abl) oncoprotein was established from a patient with CML in blast cris is. The MC3 cells showed the trilineage phenotype of myeloid, lymphoid (CD19) and megakaryocytoid lineages, and had a proliferative response to rhIL-1 and rhIL-3 in the serum-free culture. These results and the expression of CD34 indicated that the MC3 cells have characteristics of hematopoietic progenitor cells. Recently, it has been documented th at alterations of the p53 gene in leukemic cells are frequently detect ed during the blast crisis of CML. The MC3 cells contained the altered p53 gene. In addition, the original leukemic cells showed the point-m utational activation of the N-ras gene and an additional chromosomal a bnormality inv(3q), but the MC3 cells contained no such abnormalities, indicating that not all of the original leukemic cells had these abno rmalities. Thus, the MC3 cell line may provide several insights into i nvestigations of the blast crisis in CML as well as hematopoietic prog enitor cells.