ABSTRACT
Gastrointestinal tract carcinoma is one of the leading causes of cancer-related death in China. Chemoprevention has been considered as a potential approach to control this type of disease. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a redox-sensitive transcription factor that protects cells from oxidative/electrophilic stresses by activating the expression of a battery of cytoprotective genes through the antioxidant response element (ARE). Recently, Nrf2 has emerged as a novel target for chemoprevention. Several natural or synthetic chemicals, which activate Nrf2/ARE signaling pathway, have showed effect in animal models, and promises in many ongoing clinical trials. This review summarizes the recent findings on the regulation of Nrf2/ARE signaling pathway, and the developments in both preclinical and clinical studies.
Subject(s)
Animals , Humans , Anticarcinogenic Agents , Pharmacology , Antioxidants , Metabolism , Chemoprevention , Digestive System Neoplasms , Genetics , Metabolism , NF-E2-Related Factor 2 , Genetics , Metabolism , Oxidative Stress , Response Elements , Genetics , Signal TransductionABSTRACT
<p><b>OBJECTIVE</b>To maked a Nrf2 down-regulated cell line by over-expressing Keap1 in H460 cells to study the role of Nrf2 in drug resistance.</p><p><b>METHODS</b>Transfecting H460 cells with mKeap1-pEGFP and screenig for Keap1 expressing clones by Western blotting with antibodies against Nrf2, HO-1, NQO1 and AKR1C. The cell line with Keap1 over-expression was further confirmed by real-time PCR. The cytotoxicity of H460-N5 to anti-cancer drugs was evaluated by MTS assay.</p><p><b>RESULT</b>MTS assay results showed the enhanced cytotoxicity of anticancer drugs (Oxaliplatin, Doxorubicin and Etopside) to the H460 cell line with keap1 overexpression compared to the control cell line. In H460-N0 cells, the IC(50) values of Oxaliplation and Etopside were 93 micromol/L and 100 micromol/L respectively whereas the IC(50) values of the two drugs were 42 micromol/L and 30 micromol/L correspondingly in H460-N5 cells. A Nrf2 down-regulated cell line H460-N5 and a control cell line with GFP over-expression have been identified.Down-regulation of Nrf2 enhanced the cytotoxicity of Oxaliplatin, Doxorubicin and Etopside. The IC(50) value of Doxorubicin to H460-N0 cell was above 3 mg/L, but that to H460-N5 cell was about 2 mg/L.</p><p><b>CONCLUSION</b>A Nrf2 down-regulated cell line H460-N5 and a control cell line with GFP over-expression have been identified. Down-regulation of Nrf2 enhanced the cytotoxicity of Oxaliplatin, Doxorubicin and Etopside.</p>