title: Effects of an inhibitor of the γ-secretase complex on proliferation and apoptotic parameters in a FOXL2-mutated granulosa tumor cell line (KGN).
abstract: Ovarian granulosa cell tumors (GCTs) represent 3%-5% of all ovarian malignancies. Treatments have limited proven efficacy and biologically targeted treatment is lacking. The aim of this study was to investigate the role of Notch signaling in the proliferation, steroidogenesis, apoptosis, and phosphatidylinositol 3-kinase (PI3K)/AKT pathway in a FOXL2-mutated granulosa tumor cell line (KGN) representative of the adult form of GCTs. When Notch signaling is initiated, the receptors expose a cleavage site in the extracellular domain to the metalloproteinase TACE and, following this cleavage, Notch undergoes another cleavage mediated by the presenilin-gamma-secretase complex. To achieve our goal, DAPT, an inhibitor of the gamma-secretase complex, was used to investigate the role of the Notch system in parameters associated with cell growth and death, using a human granulosa cell tumor line (KGN) as an experimental model. We observed that JAGGED1, DLL4, NOTCH1, and NOTCH4 were highly expressed in KGN cells as compared to granulosa-lutein cells obtained from assisted reproductive techniques patients. The proliferation and viability of KGN cells, as well as progesterone and estradiol production, decreased in the presence of 20 μM DAPT. Apoptotic parameters like PARP and caspase 8 cleavages, BAX, and BCLXs increased in KGN cells cultured with DAPT, whereas others such as BCL2, BCLXl, FAS, and FAS ligand did not change. AKT phosphorylation decreased and PTEN protein increased when Notch signaling was inhibited in KGN cells. We conclude that the Notch system acts as a survival pathway in KGN cells, and might be interacting with the PI3K/AKT pathway.
authors.affiliation: Instituto de Biología y Medicina Experimental (IByME-CONICET), Buenos Aires, Argentina.
authors.forename: Griselda
authors.initials: G
authors.lastname: Irusta
authors.forename: Maria Camila
authors.initials: MC
authors.lastname: Pazos
authors.forename: Camila Pazos
authors.initials: CP
authors.lastname: Maidana
authors.forename: Dalhia
authors.initials: D
authors.lastname: Abramovich
authors.forename: Ignacio
authors.initials: I
authors.lastname: De Zúñiga
authors.forename: Fernanda
authors.initials: F
authors.lastname: Parborell
authors.forename: Marta
authors.initials: M
authors.lastname: Tesone
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004151:Dipeptides; D005260:Female; D000074842:Forkhead Box Protein L2; D051858:Forkhead Transcription Factors / Q000235:genetics*; D012739:Gonadal Steroid Hormones / Q000096:biosynthesis; D006106:Granulosa Cell Tumor / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D000072100:Jagged-1 Protein; D008565:Membrane Proteins / Q000378:metabolism; D009154:Mutation; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism*; D051880:Receptors, Notch / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000072099:Serrate-Jagged Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C424126:DLL4 protein, human; D004151:Dipeptides; C421604:FOXL2 protein, human; D000074842:Forkhead Box Protein L2; D051858:Forkhead Transcription Factors; D012739:Gonadal Steroid Hormones; D036341:Intercellular Signaling Peptides and Proteins; C000606273:JAG1 protein, human; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester; D051880:Receptors, Notch; D000072099:Serrate-Jagged Proteins; D053829:Amyloid Precursor Protein Secretases
keywords: KGN cells; Notch system; PI3K/AKT signaling; apoptosis