Aurora kinase A and B as new treatment targets in aromatase inhibitor-resistant breast cancer cells

Breast Cancer Res Treat. 2015 Feb;149(3):715-26. doi: 10.1007/s10549-015-3284-8. Epub 2015 Feb 10.

Abstract

Aromatase inhibitors (AIs) are used for treatment of estrogen receptor α (ER)-positive breast cancer; however, resistance is a major obstacle for optimal outcome. This preclinical study aimed at identifying potential new treatment targets in AI-resistant breast cancer cells. Parental MCF-7 breast cancer cells and four newly established cell lines, resistant to the AIs exemestane or letrozole, were used for a functional kinase inhibitor screen. A library comprising 195 different compounds was tested for preferential growth inhibition of AI-resistant cell lines. Selected targets were validated by analysis of cell growth, cell cycle phase distribution, protein expression, and subcellular localization. We identified 24 compounds, including several inhibitors of Aurora kinases e.g., JNJ-7706621 and barasertib. Protein expression of Aurora kinase A and B was found upregulated in AI-resistant cells compared with MCF-7, and knockdown studies showed that Aurora kinase A was essential for AI-resistant cell growth. In AI-resistant cell lines, the clinically relevant Aurora kinase inhibitors alisertib and danusertib blocked cell cycle progression at the G2/M phase, interfered with chromosome alignment and spindle pole formation, and resulted in preferential growth inhibition compared with parental MCF-7 cells. Even further growth inhibition was obtained when combining the Aurora kinase inhibitors with the antiestrogen fulvestrant. Our study is the first to demonstrate that Aurora kinase A and B may be treatment targets in AI-resistant cells, and our data suggest that therapy targeting both ER and Aurora kinases may be a potent treatment strategy for overcoming AI resistance in breast cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aromatase Inhibitors / administration & dosage*
  • Aurora Kinase A / biosynthesis
  • Aurora Kinase A / genetics*
  • Aurora Kinase B / biosynthesis
  • Aurora Kinase B / genetics*
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • Drug Resistance, Neoplasm / genetics
  • Estrogen Receptor alpha / antagonists & inhibitors
  • Estrogen Receptor alpha / genetics
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Knockdown Techniques
  • Humans
  • MCF-7 Cells
  • Organophosphates / administration & dosage
  • Quinazolines / administration & dosage
  • Small Molecule Libraries / administration & dosage
  • Triazoles / administration & dosage

Substances

  • 2-((3-((4-((5-(2-((3-fluorophenyl)amino)-2-oxoethyl)-1H-pyrazol-3-yl)amino)quinazolin-7-yl)oxy)propyl)(ethyl)amino)ethyl dihydrogen phosphate
  • Aromatase Inhibitors
  • Estrogen Receptor alpha
  • JNJ-7706621
  • Organophosphates
  • Quinazolines
  • Small Molecule Libraries
  • Triazoles
  • AURKA protein, human
  • AURKB protein, human
  • Aurora Kinase A
  • Aurora Kinase B