Redox regulation in stem-like cancer cells by CD44 variant isoforms

Oncogene. 2013 Oct 31;32(44):5191-8. doi: 10.1038/onc.2012.638. Epub 2013 Jan 21.


Increasing evidence indicates that several types of solid tumor are hierarchically organized and sustained by a distinct population of cancer stem cells (CSCs). CSCs possess enhanced mechanisms of protection from stress induced by reactive oxygen species (ROS) that render them resistant to chemo- and radiotherapy. Expression of CD44, especially variant isoforms (CD44v) of this major CSC marker, contributes to ROS defense through upregulation of the synthesis of reduced glutathione (GSH), the primary intracellular antioxidant. CD44v interacts with and stabilizes xCT, a subunit of the cystine-glutamate transporter xc(-), and thereby promotes cystine uptake for GSH synthesis. Given that cancer cells are often exposed to high levels of ROS during tumor progression, the ability to avoid the consequences of such exposure is required for cancer cell survival and propagation in vivo. CSCs, in which defense against ROS is enhanced by CD44v are thus thought to drive tumor growth, chemoresistance and metastasis. Therapy targeted to the CD44v-xCT system may therefore impair the ROS defense ability of CSCs and thereby sensitize them to currently available treatments.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Biological Transport
  • Cell Hypoxia
  • Drug Resistance, Neoplasm
  • Epithelial-Mesenchymal Transition
  • Humans
  • Hyaluronan Receptors / physiology*
  • Neoplasms / drug therapy
  • Neoplasms / metabolism
  • Neoplasms / pathology*
  • Neoplastic Stem Cells / metabolism*
  • Oxidation-Reduction
  • Protein Isoforms / physiology
  • Reactive Oxygen Species / metabolism


  • CD44 protein, human
  • Hyaluronan Receptors
  • Protein Isoforms
  • Reactive Oxygen Species