TY - JOUR
T1 - Nuclear factor of activated T cells-dependent downregulation of the transcription factor glioma-associated protein 1 (GLI1) underlies the growth inhibitory properties of arachidonic acid
AU - Comba, Andrea
AU - Almada, Luciana L.
AU - Tolosa, Ezequiel J.
AU - Iguchi, Eriko
AU - Marks, David L.
AU - Messler, Marianela Vara
AU - Silva, Renata
AU - Fernandez-Barrena, Maite G.
AU - Enriquez-Hesles, Elisa
AU - Vrabel, Anne L.
AU - Botta, Bruno
AU - Di Marcotulio, Lucia
AU - Ellenrieder, Volker
AU - Eynard, Aldo R.
AU - Pasqualini, Maria E.
AU - Fernandez-Zapico, Martin E.
N1 - Funding Information:
This work was supported in part by the National Institutes of Health Grants CA136526 from the NCI, P50 CA102701 through the Mayo Clinic Pancreatic Specialized Program of Research Excellence, and P30 DK84567 through the Mayo Clinic Center for Cell Signaling in Gastroenterology (to M. E. F.-Z.), Consejo Nacional de Investigaciones Científicas y Técnicas-Argentina (CONICET)-PIP 2009–2011 Grant 11220080103014 and (CONICET)-PIP 2012–2014 Grant 11220110101010 (to A. R. E.), and Secretaria de Ciencia y Tecnología de la Universidad Nacional de Có rdoba-Argentina (SECYTUNC) Grants 214/10 (to M. E. P.). The authors have declared that no conflict of interest exists. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
PY - 2016/1/22
Y1 - 2016/1/22
N2 - Numerous reports have demonstrated a tumor inhibitory effect of polyunsaturated fatty acids (PUFAs). However, the molecular mechanisms modulating this phenomenon are in part poorly understood. Here, we provide evidence of a novel antitumoral mechanism of the PUFA arachidonic acid (AA). In vivo and in vitro experiments showed that AA treatment decreased tumor growth and metastasis and increased apoptosis. Molecular analysis of this effect showed significantly reduced expression of a subset of antiapoptotic proteins, including BCL2, BFL1/A1, and 4-1BB, in AA-treated cells.Wedemonstrated that down-regulation of the transcription factor gliomaassociated protein 1 (GLI1) in AA-treated cells is the underlying mechanism controlling BCL2, BFL1/A1, and 4-1BB expression. Using luciferase reporters, chromatin immunoprecipitation, and expression studies, we found that GLI1 binds to the promoter of these antiapoptotic molecules and regulates their expression and promoter activity. We provide evidence that AA-induced apoptosis and down-regulation of antiapoptotic genes can be inhibited by overexpressing GLI1 in AA-sensitive cells. Conversely, inhibition of GLI1 mimics AA treatments, leading to decreased tumor growth, cell viability, and expression of antiapoptotic molecules. Further characterization showed thatAArepresses GLI1 expression by stimulating nuclear translocation of NFATc1, which then binds the GLI1 promoter and represses its transcription. AA was shown to increase reactive oxygen species. Treatment with antioxidants impaired the AAinduced apoptosis and down-regulation of GLI1 and NFATc1 activation, indicating that NFATc1 activation and GLI1 repression require the generation of reactive oxygen species. Collectively, these results define a novel mechanism underlying AA antitumoral functions that may serve as a foundation for future PUFA-based therapeutic approaches.
AB - Numerous reports have demonstrated a tumor inhibitory effect of polyunsaturated fatty acids (PUFAs). However, the molecular mechanisms modulating this phenomenon are in part poorly understood. Here, we provide evidence of a novel antitumoral mechanism of the PUFA arachidonic acid (AA). In vivo and in vitro experiments showed that AA treatment decreased tumor growth and metastasis and increased apoptosis. Molecular analysis of this effect showed significantly reduced expression of a subset of antiapoptotic proteins, including BCL2, BFL1/A1, and 4-1BB, in AA-treated cells.Wedemonstrated that down-regulation of the transcription factor gliomaassociated protein 1 (GLI1) in AA-treated cells is the underlying mechanism controlling BCL2, BFL1/A1, and 4-1BB expression. Using luciferase reporters, chromatin immunoprecipitation, and expression studies, we found that GLI1 binds to the promoter of these antiapoptotic molecules and regulates their expression and promoter activity. We provide evidence that AA-induced apoptosis and down-regulation of antiapoptotic genes can be inhibited by overexpressing GLI1 in AA-sensitive cells. Conversely, inhibition of GLI1 mimics AA treatments, leading to decreased tumor growth, cell viability, and expression of antiapoptotic molecules. Further characterization showed thatAArepresses GLI1 expression by stimulating nuclear translocation of NFATc1, which then binds the GLI1 promoter and represses its transcription. AA was shown to increase reactive oxygen species. Treatment with antioxidants impaired the AAinduced apoptosis and down-regulation of GLI1 and NFATc1 activation, indicating that NFATc1 activation and GLI1 repression require the generation of reactive oxygen species. Collectively, these results define a novel mechanism underlying AA antitumoral functions that may serve as a foundation for future PUFA-based therapeutic approaches.
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U2 - 10.1074/jbc.M115.691972
DO - 10.1074/jbc.M115.691972
M3 - Article
C2 - 26601952
AN - SCOPUS:84959020431
SN - 0021-9258
VL - 291
SP - 1933
EP - 1947
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 4
ER -