title: Overexpression of Nrf2 attenuates Carmustine-induced cytotoxicity in U87MG human glioma cells.
abstract: BACKGROUND
  Malignant glioma is one of the most devastating tumors in adults with poor patient prognosis. Notably, glioma often exhibits resistance to conventional chemotherapeutic approaches, complicating patient treatments. However, the molecular mediators involved in tumor chemoresistance remain poorly defined, creating a barrier to the successful management of glioma. In the present study, we hypothesized that the antioxidant transcription factor, Nrf2 (nuclear factor erythroid-derived 2 like 2), attenuates glioma cytotoxicity to Carmustine (BCNU), a widely used chemotherapeutic agent known to modulate cellular oxidative balance.
  
  
  METHODS
  To test the hypothesis, we employed human malignant glioma cell line, U87MG and overexpression of Nrf2 in glioma cells was achieved using both pharmacological and genetic approaches.
  
  
  RESULTS
  Notably, induction of Nrf2 was associated with increased expression of heme oxygenase-1 (HO-1), a stress inducible enzyme involved in anti-oxidant defense. In addition, over expression of Nrf2 in U87MG cells significantly attenuated the cytotoxicity of Carmustine as evidenced by both cellular viability assay and flow cytometry analysis. Consistent with this, antioxidants such as glutathione and N-acetyl cysteine significantly reduced Carmustine mediated glioma cytotoxicity.
  
  
  CONCLUSIONS
  Taken together, these data strongly implicate an unexplored role of Nrf2 in glioma resistance to Carmustine and raise the possible use of Nrf2 inhibitors as adjunct to Carmustine for the treatment of malignant glioma.
authors: Sangeetha
authors: S
authors: Sukumari-Ramesh
authors: Niyathi
authors: N
authors: Prasad
authors: Cargill H
authors: CH
authors: Alleyne
authors: John R
authors: JR
authors: Vender
authors: Krishnan M
authors: KM
authors: Dhandapani
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology* / Q000633:toxicity; D000975:Antioxidants / Q000494:pharmacology; D002330:Carmustine / Q000494:pharmacology* / Q000633:toxicity; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D015870:Gene Expression; D005910:Glioma / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology; D051267:NF-E2-Related Factor 2 / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D018906:Antineoplastic Agents, Alkylating; D000975:Antioxidants; D006873:Hydroquinones; D051267:NF-E2-Related Factor 2; C018855:2-tert-butylhydroquinone; D002330:Carmustine