Curcumin protects human keratinocytes against inorganic arsenite-induced acute cytotoxicity through an NRF2-dependent mechanism

Oxid Med Cell Longev. 2013:2013:412576. doi: 10.1155/2013/412576. Epub 2013 Apr 21.

Abstract

Human exposure to inorganic arsenic leads to various dermal disorders, including hyperkeratosis and skin cancer. Curcumin is demonstrated to induce remarkable antioxidant activity in a variety of cells and tissues. The present study aimed at identifying curcumin as a potent activator of nuclear factor erythroid 2-related factor 2 (NRF2) and demonstrating its protective effect against inorganic arsenite- (iAs(3+)-) induced cytotoxicity in human keratinocytes. We found that curcumin led to nuclear accumulation of NRF2 protein and increased the expression of antioxidant response element- (ARE-) regulated genes in HaCaT keratinocytes in concentration- and time-dependent manners. High concentration of curcumin (20 μM) also increased protein expression of long isoforms of NRF1. Treatment with low concentrations of curcumin (2.5 or 5 μM) effectively increased the viability and survival of HaCaT cells against iAs(3+)-induced cytotoxicity as assessed by the MTT assay and flow cytometry and also attenuated iAs(3+)-induced expression of cleaved caspase-3 and cleaved PARP protein. Selective knockdown of NRF2 or KEAP1 by lentiviral shRNAs significantly diminished the cytoprotection conferred by curcumin, suggesting that the protection against iAs(3+)-induced cytotoxicity is dependent on the activation of NRF2. Our results provided a proof of the concept of using curcumin to activate the NRF2 pathway to alleviate arsenic-induced dermal damage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antioxidants / metabolism
  • Apoptosis / drug effects
  • Arsenites / toxicity*
  • Curcumin / pharmacology*
  • Cytoprotection / drug effects*
  • Gene Expression Regulation / drug effects
  • Humans
  • Keratinocytes / drug effects
  • Keratinocytes / metabolism*
  • Keratinocytes / pathology*
  • Luciferases / metabolism
  • NF-E2-Related Factor 2 / metabolism*
  • Protective Agents / pharmacology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Response Elements / genetics

Substances

  • Antioxidants
  • Arsenites
  • NF-E2-Related Factor 2
  • Protective Agents
  • RNA, Messenger
  • Luciferases
  • Curcumin
  • arsenite