Absence of the hybrid bcr-abl mRNA in Ph1-positive B lymphoblastoid cell lines established from a patient with chronic myelogenous leukemia.
The expression of c-abl, c-sis, c-myc and N-ras oncogenes was examined in 2 lymphoblastoid cell lines, one with Ph1 (PB-1049) and the other without Ph1 (LN-1049), both established from a patient with chronic myelogenous leukemia (CML), and in a Ph1-positive cell line (PB-1049-T) derived from a tumor formed after transplantation of PB-1049 cells in a nude mouse with reference to their tumorigenic potential in nude mice. The normal transcripts of c-abl were detected in all 3 lymphoblastoid cell lines. Although in situ hybridization of v-abl proved, and restriction endonuclease analyses of the bcr region strongly indicated the occurrence of bcr-abl rearrangement in PB-1049 and PB-1049-T, we could not obtain any evidence for the expression of the hybrid bcr-abl mRNA. These results indicate that the Ph1 translocation does not ensure the production of the hybrid bcr-abl mRNA, and that the expression of hybrid bcr-abl gene is not essential for the maintenance of tumorigenicity of these cell lines. Expression of c-sis was not detected in any of the cell lines examined, whereas the expression of c-myc was uniformly higher in the 3 cell lines than in normal control cells. The levels of N-ras expression varied considerably, probably in parallel with the changes in tumorigenicity of the cell lines. N-ras expression in the PB-1049 and PB-1049-T cell lines was higher than that in the LN-1049 line when they retained tumorigenic potential, but it fell to the level of LN-1049 with loss or decline of tumorigenicity.
D016044:Fusion Proteins, bcr-abl; D006801:Humans; D007951:Leukemia, Myeloid / Q000235:genetics*; D008214:Lymphocytes / Q000032:analysis; D008297:Male; D010677:Philadelphia Chromosome; D012334:RNA, Neoplasm / Q000032:analysis* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000032:analysis* / Q000235:genetics; D011994:Recombinant Proteins / Q000032:analysis*; D014407:Tumor Cells, Cultured / Q000032:analysis
D012334:RNA, Neoplasm; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D016044:Fusion Proteins, bcr-abl