Phosphorylation of the ATP-binding loop directs oncogenicity of drug-resistant BCR-ABL mutants.
The success of targeting kinases in cancer with small molecule inhibitors has been tempered by the emergence of drug-resistant kinase domain mutations. In patients with chronic myeloid leukemia treated with ABL inhibitors, BCR-ABL kinase domain mutations are the principal mechanism of relapse. Certain mutations are occasionally detected before treatment, suggesting increased fitness relative to wild-type p210 BCR-ABL. We evaluated the oncogenicity of eight kinase inhibitor-resistant BCR-ABL mutants and found a spectrum of potencies greater or less than p210. Although most fitness alterations correlate with changes in kinase activity, this is not the case with the T315I BCR-ABL mutation that confers clinical resistance to all currently approved ABL kinase inhibitors. Through global phosphoproteome analysis, we identified a unique phosphosubstrate signature associated with each drug-resistant allele, including a shift in phosphorylation of two tyrosines (Tyr253 and Tyr257) in the ATP binding loop (P-loop) of BCR-ABL when Thr315 is Ile or Ala. Mutational analysis of these tyrosines in the context of Thr315 mutations demonstrates that the identity of the gatekeeper residue impacts oncogenicity by altered P-loop phosphorylation. Therefore, mutations that confer clinical resistance to kinase inhibitors can substantially alter kinase function and confer novel biological properties that may impact disease progression.
Skaggs
Brian J
BJ
Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095, USA.
Gorre
Mercedes E
ME
Ryvkin
Ann
A
Burgess
Michael R
MR
Xie
Yongming
Y
Han
Yun
Y
Komisopoulou
Evangelia
E
Brown
Lauren M
LM
Loo
Joseph A
JA
Landaw
Elliot M
EM
Sawyers
Charles L
CL
Graeber
Thomas G
TG
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D004252:DNA Mutational Analysis; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D016044:Fusion Proteins, bcr-abl / Q000235:genetics* / Q000378:metabolism*; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D020125:Mutation, Missense / Q000235:genetics; D010766:Phosphorylation; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000378:metabolism; D040901:Proteomics
D047428:Protein Kinase Inhibitors; D000255:Adenosine Triphosphate; D016044:Fusion Proteins, bcr-abl