Detection of BCR-ABL gene mutations in Philadelphia chromosome positive leukemia patients resistant to STI-571 cancer therapy.
The ABL-BCR fusion protein is a constitutively activated tyrosine kinase thought to play a central role in chronic myeloid leukemia (CML) and Philadelphia (Ph) chromosome acute lymphoid leukemia (ALL). Targeting the tyrosine kinase activity of ABL-BCR has been shown to be a promising therapeutic strategy in treating this disorder. Among the tyrosine kinase inhibitors, STI571 is a very effective therapeutic agent when administered to CML patients in the stable chronic phase. However, it has been reported that many CML patients with blast cell crisis treated with STI571 relapsed and became resistant to STI571. In order to understand the possible molecular mechanisms underlying STI571 resistance caused by ABL gene mutations, we investigated 19 patients (18 CML patients and 1 Ph (+) ALL patient) who either relapsed after initial response or had no response to STI571 treatment. We used polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) analysis, dHPLC, and direct DNA sequencing to analyze any possible mutations in exons 5 to 9 of the ABL gene. Our results showed that 5 out of 19 patients had various mutations between exons 5 and 7 of the ABL gene. The Ph (+) ALL patient had a Glu255Lys mutation in exon 5 and a Thr315Ile mutation in exon 7. The Glu255Lys substitution has a G to A change, and the Thr315Ile substitution has a C to T change in the ABL gene. The other unique mutations found in this study include: Tyr253His, Met351Thr, GAA tri-nucleotides insertion, and Leu213Pro.
Chien
Ju-Huei
JH
Institute of Medical Science, Tzu Chi University, Taiwan, ROC.
Tang
Jih-Luh
JL
Chen
Rong-Long
RL
Li
Chi-Cheng
CC
Lee
Chan Ping
CP
D000328:Adult; D000368:Aged; D019943:Amino Acid Substitution; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D002648:Child; D002851:Chromatography, High Pressure Liquid; D004252:DNA Mutational Analysis; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D006801:Humans; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010879:Piperazines / Q000627:therapeutic use*; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011379:Prognosis; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011743:Pyrimidines / Q000627:therapeutic use*
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl