TY - JOUR
T1 - Combined Abl inhibitor therapy for minimizing drug resistance in chronic myeloid leukemia
T2 - Src/Abl inhibitors are compatible with imatinib
AU - O'Hare, Thomas
AU - Walters, Denise K.
AU - Stoffregen, Eric P.
AU - Sherbenou, Daniel W.
AU - Heinrich, Michael C.
AU - Deininger, Michael W.N.
AU - Druker, Brian J.
PY - 2005/10/1
Y1 - 2005/10/1
N2 - Purpose: Chronic myeloid leukemia (CML) is effectively treated with imatinib. However, reactivation of Bcr-Abl via kinase domain mutations that reduce sensitivity to imatinib can cause relapse. As combination therapy is frequently used to prevent emergence of resistance, the combination of imatinib with an inhibitor of imatinib-resistant Bcr-Abl mutants (e.g., Src/Abl inhibitors AP23848 and BMS-354825) was investigated. Experimental Design: To test this approach, cellular proliferation and Bcr-Abl tyrosine phosphorylation assays were done on Ba/F3 cells expressing wild-type (WT) Bcr-Abl and four common imatinib-resistant mutants (Y253F, E255K, T315I, and M351T). Colony-forming assays with primary CML cells were also done. Results: Both Src/Abl inhibitors retained full inhibitory capacity when coadministered with imatinib at concentrations above typical clinical levels. For cells expressing WT Bcr-Abl or the marginally imatinib-resistant mutant M351T, inclusion of imatinib at therapeutic levels enhanced the effects of the Src/Abl inhibitors. By comparison, for the highly imatinib-resistant mutants Y253F and E255K, inclusion of imatinib at clinical levels resulted in only a slight enhancement beyond the effects of the Src/Abl inhibitors. None of the inhibitors affected Bcr-AblT315I cells. Colony-forming assays with primary CML cells yielded analogous results. Conclusions: Our results indicate that Src/Abl inhibitors are compatible with imatinib and suggest that combined Abl inhibitor therapy is a feasible treatment strategy for patients with CML.
AB - Purpose: Chronic myeloid leukemia (CML) is effectively treated with imatinib. However, reactivation of Bcr-Abl via kinase domain mutations that reduce sensitivity to imatinib can cause relapse. As combination therapy is frequently used to prevent emergence of resistance, the combination of imatinib with an inhibitor of imatinib-resistant Bcr-Abl mutants (e.g., Src/Abl inhibitors AP23848 and BMS-354825) was investigated. Experimental Design: To test this approach, cellular proliferation and Bcr-Abl tyrosine phosphorylation assays were done on Ba/F3 cells expressing wild-type (WT) Bcr-Abl and four common imatinib-resistant mutants (Y253F, E255K, T315I, and M351T). Colony-forming assays with primary CML cells were also done. Results: Both Src/Abl inhibitors retained full inhibitory capacity when coadministered with imatinib at concentrations above typical clinical levels. For cells expressing WT Bcr-Abl or the marginally imatinib-resistant mutant M351T, inclusion of imatinib at therapeutic levels enhanced the effects of the Src/Abl inhibitors. By comparison, for the highly imatinib-resistant mutants Y253F and E255K, inclusion of imatinib at clinical levels resulted in only a slight enhancement beyond the effects of the Src/Abl inhibitors. None of the inhibitors affected Bcr-AblT315I cells. Colony-forming assays with primary CML cells yielded analogous results. Conclusions: Our results indicate that Src/Abl inhibitors are compatible with imatinib and suggest that combined Abl inhibitor therapy is a feasible treatment strategy for patients with CML.
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U2 - 10.1158/1078-0432.CCR-05-0622
DO - 10.1158/1078-0432.CCR-05-0622
M3 - Article
C2 - 16203792
AN - SCOPUS:26444442452
SN - 1078-0432
VL - 11
SP - 6987
EP - 6993
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 19 I
ER -