Nrf2 knockdown by shRNA inhibits tumor growth and increases efficacy of chemotherapy in cervical cancer

Cancer Chemother Pharmacol. 2012 Feb;69(2):485-94. doi: 10.1007/s00280-011-1722-9. Epub 2011 Aug 13.


Purpose: NF-E2-related factor 2 (Nrf2) is a key transcription regulator for cellular response to oxidative stress in normal cells. In cancer cells, development of chemoresistance is associated with the constitutive activation of the Nrf2-mediated antioxidant defense system. Here, we investigated the role of Nrf2 in terms of cervical cancer cell proliferation and drug resistance.

Method: To investigate whether cancer cells activate the Nrf2 system, we examined 40 surgical cervical cancer samples and 12 normal control tissues. Plasmids containing Nrf2-small hairpin RNA (shRNA) or non-targeting vector-control shRNA were transfected into CaSki cells. Using Western blots and RT-PCR assays, the expression levels of Nrf2 mediated-target genes were measured in CaSki cells stably expressing Nrf2-shRNA. To evaluate how the Nrf2 knockdown affected susceptibility to chemotherapeutic drugs, MTT and flow cytometry assays were done in vitro and confirmed by a mouse xenograft model in vivo.

Results: The Nrf2-dependent defensive system was likely fully activated in cervical tumor tissues. Genetic knockdown of endogenous Nrf2 caused a global decrease in expression of Nrf2-regulated genes. This decrease in expression levels enhanced chemotherapeutic drug-induced apoptotic death in CaSki cells with a reduced cellular glutathione level. Additionally, the combination of cisplatin treatment and Nrf2 knockdown significantly suppressed tumor growth in vivo.

Conclusion: Our findings provide evidence that the inhibition of Nrf2 activity by shRNA might be a promising therapeutic strategy to enhance the efficacy of anticancer drugs and thus can be applied further during the course of chemotherapy in the treatment of cervical cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / therapeutic use*
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Blotting, Western
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Cisplatin / therapeutic use
  • Dose-Response Relationship, Drug
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Inhibitory Concentration 50
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • NF-E2-Related Factor 2 / genetics*
  • NF-E2-Related Factor 2 / metabolism
  • RNA Interference
  • RNA, Small Interfering / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Treatment Outcome
  • Tumor Burden / drug effects
  • Tumor Burden / genetics
  • Uterine Cervical Neoplasms / drug therapy*
  • Uterine Cervical Neoplasms / genetics
  • Uterine Cervical Neoplasms / pathology
  • Xenograft Model Antitumor Assays


  • Antineoplastic Agents
  • NF-E2-Related Factor 2
  • RNA, Small Interfering
  • Cisplatin