TY - JOUR
T1 - Mutant FOXL2C134W Hijacks SMAD4 and SMAD2/3 to Drive Adult Granulosa Cell Tumors
AU - Weis-Banke, Stine E
AU - Lerdrup, Mads
AU - Kleine-Kohlbrecher, Daniela
AU - Mohammad, Faizaan
AU - Sidoli, Simone
AU - Jensen, Ole N
AU - Yanase, Toshihiko
AU - Nakamura, Tomoko
AU - Iwase, Akira
AU - Stylianou, Anthe
AU - Abu-Rustum, Nadeem R
AU - Aghajanian, Carol
AU - Soslow, Robert
AU - Da Cruz Paula, Arnaud
AU - Koche, Richard P
AU - Weigelt, Britta
AU - Christensen, Jesper
AU - Helin, Kristian
AU - Cloos, Paul A C
N1 - ©2020 American Association for Cancer Research.
PY - 2020/9/1
Y1 - 2020/9/1
N2 - The mutant protein FOXL2C134W is expressed in at least 95% of adult-type ovarian granulosa cell tumors (AGCT) and is considered to be a driver of oncogenesis in this disease. However, the molecular mechanism by which FOXL2C134W contributes to tumorigenesis is not known. Here, we show that mutant FOXL2C134W acquires the ability to bind SMAD4, forming a FOXL2C134W/SMAD4/SMAD2/3 complex that binds a novel hybrid DNA motif AGHCAHAA, unique to the FOXL2C134W mutant. This binding induced an enhancer-like chromatin state, leading to transcription of nearby genes, many of which are characteristic of epithelial-to-mesenchymal transition. FOXL2C134W also bound hybrid loci in primary AGCT. Ablation of SMAD4 or SMAD2/3 resulted in strong reduction of FOXL2C134W binding at hybrid sites and decreased expression of associated genes. Accordingly, inhibition of TGFβ mitigated the transcriptional effect of FOXL2C134W. Our results provide mechanistic insight into AGCT pathogenesis, identifying FOXL2C134W and its interaction with SMAD4 as potential therapeutic targets to this condition. SIGNIFICANCE: FOXL2C134W hijacks SMAD4 and leads to the expression of genes involved in EMT, stemness, and oncogenesis in AGCT, making FOXL2C134W and the TGFβ pathway therapeutic targets in this condition. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/17/3466/F1.large.jpg.
AB - The mutant protein FOXL2C134W is expressed in at least 95% of adult-type ovarian granulosa cell tumors (AGCT) and is considered to be a driver of oncogenesis in this disease. However, the molecular mechanism by which FOXL2C134W contributes to tumorigenesis is not known. Here, we show that mutant FOXL2C134W acquires the ability to bind SMAD4, forming a FOXL2C134W/SMAD4/SMAD2/3 complex that binds a novel hybrid DNA motif AGHCAHAA, unique to the FOXL2C134W mutant. This binding induced an enhancer-like chromatin state, leading to transcription of nearby genes, many of which are characteristic of epithelial-to-mesenchymal transition. FOXL2C134W also bound hybrid loci in primary AGCT. Ablation of SMAD4 or SMAD2/3 resulted in strong reduction of FOXL2C134W binding at hybrid sites and decreased expression of associated genes. Accordingly, inhibition of TGFβ mitigated the transcriptional effect of FOXL2C134W. Our results provide mechanistic insight into AGCT pathogenesis, identifying FOXL2C134W and its interaction with SMAD4 as potential therapeutic targets to this condition. SIGNIFICANCE: FOXL2C134W hijacks SMAD4 and leads to the expression of genes involved in EMT, stemness, and oncogenesis in AGCT, making FOXL2C134W and the TGFβ pathway therapeutic targets in this condition. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/17/3466/F1.large.jpg.
KW - Cell Line, Tumor
KW - Cells, Cultured
KW - Epithelial-Mesenchymal Transition/genetics
KW - Female
KW - Forkhead Box Protein L2/genetics
KW - Gene Expression Regulation, Neoplastic/genetics
KW - Granulosa Cell Tumor/genetics
KW - Humans
KW - Mutation
KW - Smad Proteins/metabolism
KW - Smad2 Protein/metabolism
KW - Smad3 Protein/metabolism
KW - Smad4 Protein/metabolism
U2 - 10.1158/0008-5472.CAN-20-0259
DO - 10.1158/0008-5472.CAN-20-0259
M3 - Journal article
C2 - 32641411
SN - 0008-5472
VL - 80
SP - 3466
EP - 3479
JO - Cancer Research
JF - Cancer Research
IS - 17
ER -