FOXO1/3 and PTEN Depletion in Granulosa Cells Promotes Ovarian Granulosa Cell Tumor Development
Ontology highlight
ABSTRACT: The Forkhead Box, FOXO1 and FOXO3, transcription factors regulate multiple functions in mammalian cells. Selective inactivation of the Foxo1 and Foxo3 genes in murine ovarian granulosa cells severely impairs follicular development and apoptosis causing infertility, and as shown herein, granulosa cell tumor (GCT) formation. Coordinate depletion of the tumor suppressor Pten gene in the Foxo1/3 strain enhanced the penetrance and onset of GCT formation
Project description:The Forkhead Box, FOXO1 and FOXO3, transcription factors regulate multiple functions in mammalian cells. Selective inactivation of the Foxo1 and Foxo3 genes in murine ovarian granulosa cells severely impairs follicular development and apoptosis causing infertility, and as shown herein, granulosa cell tumor (GCT) formation. Coordinate depletion of the tumor suppressor Pten gene in the Foxo1/3 strain enhanced the penetrance and onset of GCT formation A direct comparison of ovarian granulosa cells from wild type d25 and FOXO/PTEN knockout granulosa cell tumors.
Project description:The Foxo transcription factors regulate multiple cellular functions. Foxo1 and Foxo3 are highly expressed in granulosa cells of ovarian follicles. Selective depletion of the Foxo1 and Foxo3 genes in granulosa cells revealed a novel ovarian-pituitary endocrine feedback loop characterized by: 1) undetectable levels of serum FSH but not LH, 2) reduced expression of the pituitary Fshb gene and its transcriptional regulators and 3) ovarian production of a factor(s) that suppresses pituitary cell Fshb. Equally notable and independent of FSH, depletion of Foxo1/3 altered the expression of specific genes associated with follicle growth versus apoptosis by disrupting critical regulatory interactions of Foxo1/3 with the activin and BMP2 pathways, respectively. As a consequence, granulosa cell proliferation and apoptosis were decreased. These data provide the first evidence that Foxo1/3 divergently regulate follicle growth or death by interacting with the activin and BMP pathways in granulosa cells and by modulating pituitary FSH production. A direct comparison of ovarian granulosa cells from wild type d25, Foxo1/3 dKO d25 and Foxo1/3 dKO 2 month mice.
Project description:The Foxo transcription factors regulate multiple cellular functions. Foxo1 and Foxo3 are highly expressed in granulosa cells of ovarian follicles. Selective depletion of the Foxo1 and Foxo3 genes in granulosa cells revealed a novel ovarian-pituitary endocrine feedback loop characterized by: 1) undetectable levels of serum FSH but not LH, 2) reduced expression of the pituitary Fshb gene and its transcriptional regulators and 3) ovarian production of a factor(s) that suppresses pituitary cell Fshb. Equally notable and independent of FSH, depletion of Foxo1/3 altered the expression of specific genes associated with follicle growth versus apoptosis by disrupting critical regulatory interactions of Foxo1/3 with the activin and BMP2 pathways, respectively. As a consequence, granulosa cell proliferation and apoptosis were decreased. These data provide the first evidence that Foxo1/3 divergently regulate follicle growth or death by interacting with the activin and BMP pathways in granulosa cells and by modulating pituitary FSH production.
Project description:The forkhead box transcription factor FOXO1 is highly expressed in granulosa cells of growing follicles but is down-regulated by FSH in culture or by LH-induced luteinization in vivo. To analyze the function of FOXO1, we infected rat and mouse granulosa cells with adenoviral vectors expressing two FOXO1 mutants: a gain-of-function mutant FOXOA3 that has two serine residues and one threonine residue mutated to alanines rendering this protein constitutively active and nuclear, and a FOXOA3-mutant DNA-binding domain (mDBD) in which the DBD is mutated. The infected cells were then treated with vehicle or FSH for specific time intervals. Infection of the granulosa cells was highly efficient, caused only minimal apoptosis, and maintained FOXO1 protein at levels of the endogenous protein observed in cells before exposure to FSH. RNA was prepared from control and adenoviral infected cells exposed to vehicle or FSH for 12 and 24 h. Affymetrix microarray and database analyses identified, and real time RT-PCR verified, that genes within the lipid, sterol, and steroidogenic biosynthetic pathways (Hmgcs1, Hmgcr, Mvk, Sqle, Lss, Cyp51, Tm7sf2, Dhcr24 and Star, Cyp11a1, and Cyp19), including two key transcriptional regulators Srebf1 and Srebf2 of cholesterol biosynthesis and steroidogenesis (Nr5a1, Nr5a2), were major targets induced by FSH and suppressed by FOXOA3 and FOXOA3-mDBD in the cultured granulosa cells. By contrast, FOXOA3 and FOXOA3- mDBD induced expression of Cyp27a1 mRNA that encodes an enzyme involved in cholesterol catabolism to oxysterols. The genes up-regulated by FSH in cultured granulosa cells were also induced in granulosa cells of preovulatory follicles and corpora lutea collected from immature mice primed with FSH (equine choriogonadotropin) and LH (human choriogonadotropin), respectively. Conversely, Foxo1 and Cyp27a1 mRNAs were reduced by these same treatments. Collectively, these data provide novel evidence that FOXO1 may play a key role in granulosa cells to modulate lipid and sterol biosynthesis, thereby preventing elevated steroidogenesis during early stages of follicle development. Experiment Overall Design: Immature rat granulosa cells were affected with either control (GFP) or FOXO1 mutant adenovirus (FOXOA3 and FOXOA3-mDBD) for 4 hours. Then the cells were treated with either FSH or vehicle for 24 hours. The gene expression profiles for the four treatment samples (control, control +FSH, FOXOA3 + FSH, FOXOA3-mDBD + FSH) were compared using Rat Genome 230.2 Arrays with one array per sample.
Project description:The forkhead box transcription factor FOXO1 is highly expressed in granulosa cells of growing follicles but is down-regulated by FSH in culture or by LH-induced luteinization in vivo. To analyze the function of FOXO1, we infected rat and mouse granulosa cells with adenoviral vectors expressing two FOXO1 mutants: a gain-of-function mutant FOXOA3 that has two serine residues and one threonine residue mutated to alanines rendering this protein constitutively active and nuclear, and a FOXOA3-mutant DNA-binding domain (mDBD) in which the DBD is mutated. The infected cells were then treated with vehicle or FSH for specific time intervals. Infection of the granulosa cells was highly efficient, caused only minimal apoptosis, and maintained FOXO1 protein at levels of the endogenous protein observed in cells before exposure to FSH. RNA was prepared from control and adenoviral infected cells exposed to vehicle or FSH for 12 and 24 h. Affymetrix microarray and database analyses identified, and real time RT-PCR verified, that genes within the lipid, sterol, and steroidogenic biosynthetic pathways (Hmgcs1, Hmgcr, Mvk, Sqle, Lss, Cyp51, Tm7sf2, Dhcr24 and Star, Cyp11a1, and Cyp19), including two key transcriptional regulators Srebf1 and Srebf2 of cholesterol biosynthesis and steroidogenesis (Nr5a1, Nr5a2), were major targets induced by FSH and suppressed by FOXOA3 and FOXOA3-mDBD in the cultured granulosa cells. By contrast, FOXOA3 and FOXOA3- mDBD induced expression of Cyp27a1 mRNA that encodes an enzyme involved in cholesterol catabolism to oxysterols. The genes up-regulated by FSH in cultured granulosa cells were also induced in granulosa cells of preovulatory follicles and corpora lutea collected from immature mice primed with FSH (equine choriogonadotropin) and LH (human choriogonadotropin), respectively. Conversely, Foxo1 and Cyp27a1 mRNAs were reduced by these same treatments. Collectively, these data provide novel evidence that FOXO1 may play a key role in granulosa cells to modulate lipid and sterol biosynthesis, thereby preventing elevated steroidogenesis during early stages of follicle development.
Project description:Granulosa cell tumors (GCTs) are a rare form of stromal cell malignant cancer accounting for one in twenty cases of ovarian cancer. More than 400 tumors from aGCT patients of diverse ethnicities showed one single mutation in the Forkhead box L2 transcription factor gene FOXL2: Cys134Trp (c.402C<G). In this work, seeking more comprehensive profiling of the mutant FOXL2C134W transcriptomic activity in a model of adult Granulosa Cell Tumor (aGTC), we performed an RNA-seq analysis comparing the effect of FOXL2WT/SMAD3 and FOXL2C134W/SMAD3 overexpression in presence/absence of FOXO1 in an established human GC line (HGrC1).
Project description:Stable activation of the WNT signaling effector beta-catenin (CTNNB1(ex3) in ovarian granulosa cells results in the formation of premalignant lesions that develop into granulosa cell tumors (GCTs) spontaneously later in life. Loss of the tumor suppressor gene Pten accelerates GCT formation in the CTNNB1 strain. Conversely, expression of oncogenic KRASG12D causes the dramatic arrest of proliferation, differentiation and apoptosis in granulosa cells, and consequently, small abnormal follicle-like structures devoid of oocytes accumulate in the ovary. Because of the potent anti-proliferative effects of KRASG12D in granulosa cells, we sought to determine if KRASG12D would block precancerous lesion and tumor formation in follicles of the CTNNB1 mutant mice. Unexpectedly, transgenic Ctnnb1;Kras mutant mice developed early-onset GCTs leading to premature death in a manner similar to theCtnnb1;Pten mutant mice. Moreover, the GCTs in the Ctnnb1;Kras mutant mice exhibited increased GC proliferation, decreased apoptosis and impaired differentiation. Microarray and RT-PCR analyses revealed that ovaries from mice expressing dominant-stable CTNNB1 with either Pten loss or KRAS activation were unpredictably similar. Specifically, gene regulatory processes induced by CTNNB1 were mostly enhanced by either KRAS activation or Pten loss in remarkably similar patterns and degree. Furthermore, the concomitant activation of CTNNB1 and KRAS in Sertoli cells resulted in the development of granulosa cell tumors of the testis. RT-PCR studies showed a partial overlap in gene regulatory processes associated with tumor development in the ovary and testis. Together, these results suggest that KRAS activation and Pten loss induce GCT development from premalignant lesions via highly similar molecular mechanisms. four samples: average of two wild type samples (previously submitted as GSM403220 and GSM403221), beta-Catenin constitutively active mutant, beta-Catenin;Pten double mutant, and beta-Catenin;Kras(G12D) double mutant
Project description:Stable activation of the WNT signaling effector beta-catenin (CTNNB1(ex3) in ovarian granulosa cells results in the formation of premalignant lesions that develop into granulosa cell tumors (GCTs) spontaneously later in life. Loss of the tumor suppressor gene Pten accelerates GCT formation in the CTNNB1 strain. Conversely, expression of oncogenic KRASG12D causes the dramatic arrest of proliferation, differentiation and apoptosis in granulosa cells, and consequently, small abnormal follicle-like structures devoid of oocytes accumulate in the ovary. Because of the potent anti-proliferative effects of KRASG12D in granulosa cells, we sought to determine if KRASG12D would block precancerous lesion and tumor formation in follicles of the CTNNB1 mutant mice. Unexpectedly, transgenic Ctnnb1;Kras mutant mice developed early-onset GCTs leading to premature death in a manner similar to theCtnnb1;Pten mutant mice. Moreover, the GCTs in the Ctnnb1;Kras mutant mice exhibited increased GC proliferation, decreased apoptosis and impaired differentiation. Microarray and RT-PCR analyses revealed that ovaries from mice expressing dominant-stable CTNNB1 with either Pten loss or KRAS activation were unpredictably similar. Specifically, gene regulatory processes induced by CTNNB1 were mostly enhanced by either KRAS activation or Pten loss in remarkably similar patterns and degree. Furthermore, the concomitant activation of CTNNB1 and KRAS in Sertoli cells resulted in the development of granulosa cell tumors of the testis. RT-PCR studies showed a partial overlap in gene regulatory processes associated with tumor development in the ovary and testis. Together, these results suggest that KRAS activation and Pten loss induce GCT development from premalignant lesions via highly similar molecular mechanisms.
Project description:The mammalian FoxO transcription factors - FoxO1, FoxO3, FoxO4 - function in the nucleus to direct transcription of specific gene targets governing cellular survival, proliferation, metabolism, differentiation and oxidative defense. Activation of PI3K by extracellular growth factors leads to AKT-mediated phosphorylation of FoxO1, FoxO3 and FoxO4, resulting in their sequestration in the cytoplasm such that they are unable to regulate their gene targets. Our study identified FoxOs as novel tumor suppressors in kidney cancer (Gan et al, 2010, Cancer Cell). To understand the tumor suppression function of FoxOs in kidney cancer cells, we performed gene expression profiling in human kidney cancer cells upon FoxO1 or FoxO3 reactivation in order to identify the key transcriptomic alterations mediating FoxO tumor suppression function in kidney cancer cells. We generated RCC4 and UMRC2 cell lines (two human kidney cancer cells with low endogenous FoxO1 and FoxO3 expression) with stable expression of FoxO1(TA)ERT2 or FoxO3(TA)ERT2 construct, which expressed a fusion protein consisting of FoxO(TA) (containing three Ser/Thr AKT phosphorylation sites mutated to alanine) fused to the T2-modified estrogen receptor (ERT2) moiety. We documented that the FoxO(TA)ERT2 fusion protein sequestered FoxO(TA) in the cytoplasm and that 4OHT treatment resulted in rapid translocation of FoxO(TA)ERT2 into the nucleus. We also established stable cell lines with ERT2 expression as control cell lines. (For simplicity, ERT2, FoxO1(TA)ERT2 and FoxO3(TA)ERT2 cell lines will be referred to as EV (empty vector), FoxO1 and FoxO3, respectively, hereafter). We then conducted comparative transcriptome analysis (using the Human Genome U133 Plus 2.0 Array) of EV, FoxO1, or FoxO3-expressing RCC4 and UMRC2 cells at 12 hours with or without 100 nm 4OHT treatment (cultured in DMEM+10% FBS with puromycin selection). To enrich for more proximal actions of FoxO, we selected the 12 hour time point as time course studies revealed dramatic transcriptional changes of known FoxO targets (such as Cyclin D1), yet no discernable cellular phenotypes (apoptosis and cell cycle arrest). We generated 4 transcriptome datasets: FoxO1 RCC4, FoxO3 RCC4, FoxO1 UMRC2, and FoxO3 UMRC2 (by comparing transcriptome data with or without 4OHT treatment), and normalized these transcriptome data against 4OHT-treated EV cells, which show modest 4OHT-induced transcriptional changes.