Crosstalk between NRF2 and HIPK2 shapes cytoprotective responses

Oncogene. 2017 Nov 2;36(44):6204-6212. doi: 10.1038/onc.2017.221. Epub 2017 Jul 10.

Abstract

Homeodomain interacting protein kinase-2 (HIPK2) is a member of the HIPK family of stress-responsive kinases that modulates cell growth, apoptosis, proliferation and development. HIPK2 has several well-characterised tumour suppressor roles, but recent studies suggest it can also contribute to tumour progression, although the underlying mechanisms are unknown. Herein, we have identified novel crosstalk between HIPK2 and the cytoprotective transcription factor NRF2. We show that HIPK2 is a direct transcriptional target of NRF2, identifying a functional NRF2 binding site in the HIPK2 gene locus and demonstrating for the first time a transcriptional mode of regulation for this kinase. In addition, HIPK2 is required for robust NRF2 responsiveness in cells and in vivo. By using both gain-of-function and loss-of-function approaches, we demonstrate that HIPK2 can elicit a cytoprotective response in cancer cells via NRF2. Our results have uncovered a new downstream effector of HIPK2, NRF2, which is frequently activated in human tumours correlating with chemoresistance and poor prognosis. Furthermore, our results suggest that modulation of either HIPK2 levels or activity could be exploited to impair NRF2-mediated signalling in cancer cells, and thus sensitise them to chemotherapeutic drugs.

MeSH terms

  • A549 Cells
  • Animals
  • Apoptosis / drug effects
  • Binding Sites
  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism
  • Cell Proliferation / drug effects*
  • Doxorubicin / administration & dosage
  • Drug Resistance, Neoplasm / genetics
  • Humans
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / pathology
  • Mice
  • NF-E2-Related Factor 2 / genetics*
  • NF-E2-Related Factor 2 / metabolism
  • Protein Binding
  • Protein Serine-Threonine Kinases / genetics*
  • Protein Serine-Threonine Kinases / metabolism
  • Signal Transduction / drug effects
  • Xenograft Model Antitumor Assays

Substances

  • Carrier Proteins
  • NF-E2-Related Factor 2
  • NFE2L2 protein, human
  • Doxorubicin
  • HIPK2 protein, human
  • Protein Serine-Threonine Kinases