title: Nuclear Factor of Activated T Cells-dependent Down-regulation of the Transcription Factor Glioma-associated Protein 1 (GLI1) Underlies the Growth Inhibitory Properties of Arachidonic Acid.
abstract: 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. We demonstrated that down-regulation of the transcription factor glioma-associated 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 that AA represses 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 AA-induced 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.
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905,; Instituto de Investigaciones en Ciencias de la Salud, Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Médicas-Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Andrea
authors.initials: A
authors.lastname: Comba
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: Luciana L
authors.initials: LL
authors.lastname: Almada
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: Ezequiel J
authors.initials: EJ
authors.lastname: Tolosa
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: Eriko
authors.initials: E
authors.lastname: Iguchi
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: David L
authors.initials: DL
authors.lastname: Marks
authors.affiliation: Instituto de Investigaciones en Ciencias de la Salud, Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Médicas-Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Marianela
authors.initials: M
authors.lastname: Vara Messler
authors.affiliation: Instituto de Investigaciones en Ciencias de la Salud, Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Médicas-Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Renata
authors.initials: R
authors.lastname: Silva
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905,. Electronic address: fernandezzapico.martin@mayo.edu.
authors.forename: Maite G
authors.initials: MG
authors.lastname: Fernandez-Barrena
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: Elisa
authors.initials: E
authors.lastname: Enriquez-Hesles
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: Anne L
authors.initials: AL
authors.lastname: Vrabel
authors.affiliation: Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza University, Center for Life Nano Science at Sapienza, Istituto Italiano di Tecnologia, 00161 Rome, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Botta
authors.affiliation: Department of Molecular Medicine, Sapienza University, Pasteur Institute/Cenci-Bolognetti Foundation, 00161 Rome, Italy, and.
authors.forename: Lucia
authors.initials: L
authors.lastname: Di Marcotulio
authors.affiliation: Gastroenterology and Gastrointestinal Oncology, University Medical Center Göttingen, 37075 Göttingen, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Ellenrieder
authors.affiliation: Instituto de Investigaciones en Ciencias de la Salud, Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Médicas-Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Aldo R
authors.initials: AR
authors.lastname: Eynard
authors.affiliation: Instituto de Investigaciones en Ciencias de la Salud, Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Médicas-Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Pasqualini
authors.affiliation: From the Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: Martin E
authors.initials: ME
authors.lastname: Fernandez-Zapico
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D059045:Chromosomal Puffs; D015536:Down-Regulation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D000071676:Zinc Finger Protein GLI1
chemical_list: C400551:GLI1 protein, human; D050778:NFATC Transcription Factors; C494003:NFATC1 protein, human; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1; D016718:Arachidonic Acid
keywords: GLI1; arachidonic acid (AA) (ARA); cancer; cell death; polyunsaturated fatty acid (PUFA); transcription factor