title: Inhibition of juvenile myelomonocytic leukemia cell growth in vitro by farnesyltransferase inhibitors.
abstract: Juvenile myelomonocytic leukemia (JMML) is an early childhood disease for which there is no effective therapy. Therapy with 13-cis retinoic acid or low-dose chemotherapy can induce some responses, but neither mode is curative. Stem cell transplantation can produce lasting remissions but is hampered by high rates of relapse. The pathogenesis of JMML involves deregulated cytokine signal transduction through the Ras signaling pathway, with resultant selective hypersensitivity of JMML cells to granulocyte-macrophage colony-stimulating factor (GM-CSF). A JMML mouse model, achieved through homozygous deletion of the neurofibromatosis gene, confirmed the involvement of deregulated Ras in JMML pathogenesis. With this pathogenetic knowledge, mechanism-based treatments are now being developed and tested. Ras is critically dependent on a prenylation reaction for its signal transduction abilities. Farnesyltransferase inhibitors are compounds that were developed specifically to block the prenylation of Ras. Two of these compounds, L-739,749 and L-744, 832, were tested for their ability to inhibit spontaneous JMML granulocyte-macrophage colony growth. Within a dose range of 1 to 10 micromol/L, each compound demonstrated dose-dependent inhibition of JMML colony growth. An age-matched patient with a different disease and GM-CSF-stimulated normal adult marrow cells also demonstrated dose-dependent inhibitory effects on colony growth, but they were far less sensitive to these compounds than JMML hematopoietic progenitors. Even if the addition of L-739,749 were delayed for 5 days, significant inhibitory effects would still show in JMML cultures. These results demonstrate that a putative Ras-blocking compound can have significant growth inhibitory effects in vitro, perhaps indicating a potential treatment for JMML. (Blood. 2000;95:639-645)
authors.affiliation: Departments of Medicine and Pediatrics, Divisions of Hematology/Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35294-3300, USA. peter.emanuel@ccc.uab.edu
authors.forename: P D
authors.initials: PD
authors.lastname: Emanuel
authors.forename: R C
authors.initials: RC
authors.lastname: Snyder
authors.forename: T
authors.initials: T
authors.lastname: Wiley
authors.forename: B
authors.initials: B
authors.lastname: Gopurala
authors.forename: R P
authors.initials: RP
authors.lastname: Castleberry
mesh_terms: D000328:Adult; D019883:Alkyl and Aryl Transferases / Q000037:antagonists & inhibitors*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001854:Bone Marrow Cells / Q000166:cytology / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002648:Child; D003114:Colony-Forming Units Assay; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D051231:Farnesyltranstransferase; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects / Q000473:pathology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000473:pathology*; D006801:Humans; D015477:Leukemia, Myelomonocytic, Chronic / Q000473:pathology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000473:pathology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000473:pathology; D008715:Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051379:Mice; D008817:Mice, Mutant Strains; D009842:Oligopeptides / Q000494:pharmacology*; D017368:Protein Prenylation / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; C096898:L 744832; D009842:Oligopeptides; C087363:L 739749; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D008715:Methionine; D019883:Alkyl and Aryl Transferases; D051231:Farnesyltranstransferase