Ferroptosis and autophagy induced cell death occur independently after siramesine and lapatinib treatment in breast cancer cells

PLoS One. 2017 Aug 21;12(8):e0182921. doi: 10.1371/journal.pone.0182921. eCollection 2017.

Abstract

Ferroptosis is a cell death pathway characterized by iron-dependent accumulation of reactive oxygen species (ROS) within the cell. The combination of siramesine, a lysosome disruptor, and lapatinib, a dual tyrosine kinase inhibitor, has been shown to synergistically induce cell death in breast cancer cells mediated by ferroptosis. These treatments also induce autophagy but its role in this synergistic cell death is unclear. In this study, we determined that siramesine and lapatinib initially induced ferroptosis but changes to an autophagy induced cell death after 24 hours. Furthermore, we found that intracellular iron level increased in a time dependent manner following treatment accompanied by an increase in ROS. Using the iron chelator deferoxamine (DFO) or the ROS scavenger alpha-tocopherol decreased both autophagy flux and cell death. We further discovered that decreased expression of the iron storage protein, ferritin was partially dependent upon autophagy degradation. In contrast, the expression of transferrin, which is responsible for the transport of iron into cells, is increased following treatment with lapatinib alone or in combination with siramesine. This indicates that ferroptosis and autophagy induced cell death occur independently but both are mediated by iron dependent ROS generation in breast cancer cells.

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis*
  • Autophagy*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology*
  • Cell Line, Tumor
  • Female
  • Ferritins / metabolism
  • Humans
  • Indoles / pharmacology*
  • Lapatinib
  • Quinazolines / pharmacology*
  • Reactive Oxygen Species / metabolism
  • Spiro Compounds / pharmacology*

Substances

  • Antineoplastic Agents
  • Indoles
  • Lu 28-179
  • Quinazolines
  • Reactive Oxygen Species
  • Spiro Compounds
  • Lapatinib
  • Ferritins

Grants and funding

This study was supported by an operating grant from the CancerCare Manitoba Foundation and the Canadian Breast Cancer Foundation, Prairie/NWT Chapter. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.