Discovery and Protein Modeling Studies of Novel Compound Mutations Causing Resistance to Multiple Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia

Asian Pac J Cancer Prev. 2020 Dec 1;21(12):3517-3526. doi: 10.31557/APJCP.2020.21.12.3517.

Abstract

Objective: BCR-ABL fusion oncogene is the hallmark of chronic myeloid leukemia (CML), causing genomic instability which leads to accumulation of mutations in BCR-ABL as well as other genes. BCR-ABL mutations are the cause of tyrosine kinase inhibitors (TKIs) resistance in CML. Recently, compound BCR-ABL mutations have been reported to resist all FDA approved TKIs. Therefore, finding novel compound BCR-ABL mutations can help and clinically manage CML. Therefore, our objective was to find out novel drug-resistant compound BCR-ABL mutations in CML and carry out their protein modelling studies.

Methodology: Peripheral blood samples were collected from ten imatinib resistant CML patients receiving nilotinib treatment. BCR-ABL transcript mutations were investigated by employing capillary sequencing. Patient follow-up was carried out using European LeukemiaNet guidelines. Protein modeling studies were carried out for new compound mutations using PyMol to see the effects of mutations at structural level.

Results: A novel compound mutation (K245N mutation along with G250W mutation) and previously known T351I utation was detected in two of the nilotinib resistance CML patients respectively while in the rest of 8 nilotinib responders, no resistant mutations were detected. Protein modelling studies indicated changes in BCR-ABL mutant protein which may have negatively impacted its binding with nilotinib leading to drug resistance.

Conclusion: We report a novel nilotinib resistant BCR-ABL compound mutation (K245N along with G250W mutation) which impacts structural modification in BCR-ABL mutant protein leading to drug resistance. As compound mutations pose a new threat by causing resistance to all FDA approved tyrosine kinase inhibitors in BCR-ABL+ leukemias, our study opens a new direction for in vitro characterization of novel BCR-ABL compound mutations and their resistant to second generation and third generation TKIs.

Keywords: BCR-ABL Mutation; Chronic myeloid leukemia; Nilotinib; tyrosine kinase inhibitors.

MeSH terms

  • Adult
  • Biomarkers, Tumor / genetics*
  • Drug Resistance, Neoplasm / drug effects*
  • Female
  • Follow-Up Studies
  • Fusion Proteins, bcr-abl / chemistry*
  • Fusion Proteins, bcr-abl / genetics*
  • Humans
  • Imatinib Mesylate / pharmacology*
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / drug therapy*
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / genetics
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / pathology
  • Male
  • Middle Aged
  • Models, Molecular
  • Mutation*
  • Prognosis
  • Protein Conformation
  • Protein Kinase Inhibitors / pharmacology

Substances

  • Biomarkers, Tumor
  • Protein Kinase Inhibitors
  • Imatinib Mesylate
  • Fusion Proteins, bcr-abl