Integrin-Linked Kinase Mediates Therapeutic Resistance of Quiescent CML Stem Cells to Tyrosine Kinase Inhibitors

Cell Stem Cell. 2020 Jul 2;27(1):110-124.e9. doi: 10.1016/j.stem.2020.04.005. Epub 2020 May 14.

Abstract

Patients with chronic myeloid leukemia (CML) often require lifelong therapy with ABL1 tyrosine kinase inhibitors (TKIs) due to a persisting TKI-resistant population of leukemic stem cells (LSCs). From transcriptome profiling, we show integrin-linked kinase (ILK), a key constituent of focal adhesions, is highly expressed in TKI-nonresponsive patient cells and their LSCs. Genetic and pharmacological inhibition of ILK impaired the survival of nonresponder patient cells, sensitizing them to TKIs, even in the presence of protective niche cells. Furthermore, ILK inhibition eliminated TKI-refractory LSCs from patients, but not normal HSCs, in vitro and in vivo. RNA-sequencing and functional validation studies implicated an important role of ILK in maintaining a requisite level of mitochondrial oxidative metabolism in highly purified, quiescent LSCs. Thus, these findings point to ILK as a critical survival mediator to TKIs and quiescent stem cells, offering an attractive therapeutic target and model for curative combination therapies in stem-cell-driven cancers.

Keywords: bone marrow niche; chronic myeloid leukemia; focal adhesions; integrin-linked kinase; leukemic stem cells; oxidative phosphorylation; quiescence; reactive oxygen species; therapy resistance; tyrosine kinase inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Drug Resistance, Neoplasm
  • Fusion Proteins, bcr-abl*
  • Humans
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive* / drug therapy
  • Neoplastic Stem Cells
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use
  • Protein Serine-Threonine Kinases

Substances

  • Protein Kinase Inhibitors
  • integrin-linked kinase
  • Fusion Proteins, bcr-abl
  • Protein Serine-Threonine Kinases

Grant support