Transcriptional Role of FOXO1 in Drug Resistance through Antioxidant Defense Systems

  • Tomoko GotoEmail author
  • Masashi Takano
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 665)


FOXO transcription factors promote cell cycle arrest, apoptosis, DNA damage repair and detoxification of reactive oxygen species by regulating specific gene setting. As FOXO possess diverse functions, which partly seemed opposing, the multiple mechanisms, including transcriptional activity and subcellular localization, are differentially regulated according to various types or intensities of cellular stress responses. Since FOXO transcription factors are critical mediators of apoptosis in cytotoxicity inducing drugs, its involvement in the development of drug resistance is an important issue in cancer therapy. Indeed, FOXO1 expression was distinctively upregulated in paclitaxel resistant cell line and enhanced by exposure to paclitaxel with subcellular translocation. In addition, FOXO1 overexpression, predominantly in cytosol, was frequently observed in cancer tissue samples from chemoresistant patients compared to chemosensitive patients. FOXO1 silencing in paclitaxel resistant cell line decreased its resistance through modulation of downstream targets of FOXO1 involving oxidative stress. Alteration of oxidative stress by cotreatment with pharmacologic modulators of reactive oxygen species also attenuated cytotoxicity of paclitaxel. Furthermore, FOXO1 silencing attenuated intracellular reactive oxygen species levels, which collectively suggest one of possible explanations in transcriptional role of FOXO1 as redox mechanism leading to drug resistance through its downstream target involving defence mechanism against oxidative stress.


Ovarian Cancer Cell Line Endometrial Cancer Cell Forkhead Transcription Factor Ishikawa Cell FOXO Transcription Factor 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Landes Bioscience and Springer+Business Media 2009

Authors and Affiliations

  1. 1.Department of Obstetrics and GynecologyNational Defense Medical CollegeTokorozawa, SaitamaJapan

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