Ribozyme-mediated inhibition of a Philadelphia chromosome-positive acute lymphoblastic leukemia cell line expressing the p190 bcr-abl oncogene.
The bcr-abl oncogene is the molecular counterpart of the Philadelphia chromosome (Ph), which is detected in > 95% of patients with chronic myelogenous leukemia (CML) and 20-30% of adults with acute lymphoblastic leukemia (ALL). Leukemic cells from patients with CML express the p210 form of the bcr-abl oncogene, whereas in adult Ph+ ALL approximately 50% of cases express the p190 form of the bcr-abl oncogene, and the other 50% express the same p210 gene as is found in CML. In this study, we have designed hairpin ribozymes (RZs) specific for the p190 form of the bcr-abl oncogene to inhibit the growth of a p190 Ph+ ALL cell line, Sup-B15. The RZs cleave p190 RNA substrate in a cell-free in vitro assay. In the presence of the liposome, DMRIE-C, the RZs are protected from serum mediated catalysis in vitro. Anti-p190 RZs transfected with DMRIE-C as the vector into K562 cells, which express the p210 bcr-abl oncogene, are stable intracellularly for up to 96 hours. Up to 33% of the DMRIE-C and RZ mixtures are taken up by Sup-B15 cells cultured in suspension. Expression of the p190 bcr-abl protein product is specifically inhibited as demonstrated by Western blot analysis. Cell growth of the Sup-B15 cells is completely inhibited by anti-p190 RZs over four days in culture. Anti-p210 RZs have no significant effect on bcr-abl protein expression or cell growth by Sup-B15 cells. RZs may have a role in purging stem cell populations collected from patients with Ph+ ALL in the context of autologous bone marrow transplantation.
Snyder
D S
DS
Department of Hematology and Bone Marrow Transplantation, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA.
Wu
Y
Y
McMahon
R
R
Yu
L
L
Rossi
J J
JJ
Forman
S J
SJ
D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D004795:Enzyme Stability / Q000502:physiology; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D015870:Gene Expression; D006801:Humans; D006868:Hydrolysis; D009857:Oncogenes / Q000187:drug effects* / Q000235:genetics*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000473:pathology*; D016337:RNA, Catalytic / Q000032:analysis / Q000493:pharmacokinetics / Q000494:pharmacology*; D013379:Substrate Specificity; D014407:Tumor Cells, Cultured
D016337:RNA, Catalytic; D016044:Fusion Proteins, bcr-abl