title: Development of resistance to dasatinib in Bcr/Abl-positive acute lymphoblastic leukemia.
abstract: Dasatinib is a potent dual Abl/Src inhibitor approved for treatment of Philadelphia chromosome-positive (Ph-positive) leukemias. At a once-daily dose and a relatively short half-life of 3-5 h, tyrosine kinase inhibition is not sustained. However, transient inhibition of K562 leukemia cells with a high-dose pulse of dasatinib or long-term treatment with a lower dose was reported to irreversibly induce apoptosis. Here, the effect of dasatinib on treatment of Bcr/Abl-positive acute lymphoblastic leukemia (ALL) cells was evaluated in the presence of stromal support. Dasatinib eradicated Bcr/Abl ALL cells, caused significant apoptosis and eliminated tyrosine phosphorylation on Bcr/Abl, Src, Crkl and Stat-5. However, treatment of mouse ALL cells with lower doses of dasatinib over an extended period of time allowed the emergence of viable drug-resistant cells. Interestingly, dasatinib treatment increased cell-surface expression of CXCR4, which is important for survival of B-lineage cells, but this did not promote survival. Combined treatment of cells with dasatinib and a CXCR4 inhibitor resulted in enhanced cell death. These results do not support the concept that long-term treatment with low-dose dasatinib monotherapy will be effective in causing irreversible apoptosis in Ph-positive ALL, but suggest that combined treatment with dasatinib and drugs such as AMD3100 may be effective.
authors.affiliation: Section of Molecular Carcinogenesis, Division of Hematology/Oncology, The Saban Research Institute of Childrens Hospital Los Angeles, Los Angeles, CA 90027, USA.
authors.forename: F
authors.initials: F
authors.lastname: Fei
authors.forename: S
authors.initials: S
authors.lastname: Stoddart
authors.forename: M
authors.initials: M
authors.lastname: Müschen
authors.forename: Y-m
authors.initials: YM
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Groffen
authors.forename: N
authors.initials: N
authors.lastname: Heisterkamp
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002478:Cells, Cultured; D000069439:Dasatinib; D019008:Drug Resistance, Neoplasm; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D016044:Fusion Proteins, bcr-abl / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D007942:Leukemia, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D010766:Phosphorylation; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology*; D019718:Receptors, CXCR4 / Q000378:metabolism; D017154:Stromal Cells / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D013844:Thiazoles / Q000494:pharmacology*; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C514936:CXCR4 protein, mouse; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D019718:Receptors, CXCR4; D013844:Thiazoles; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; D019061:src-Family Kinases; D000069439:Dasatinib