Transcriptomic Profiling of Gene Expression Associated with Granulosa Cell Tumor Development in a Mouse Model

SIMPLE SUMMARY: Ovarian granulosa cell tumors are rare ovarian tumors, with poorly understood etiology. The aim of this study is to define the molecular changes in ovarian granulosa cell tumors. We used a granulosa cell tumor mouse model that contains dysregulated transforming growth factor β signaling. Using RNA-sequencing technology, we identified differentially expressed genes between tumor tissues and normal controls. In addition, comparative analyses have been performed to reveal common genes altered in ovarian granulosa cell tumors between the mouse and the human. This study has revealed the molecular signature of ovarian granulosa cell tumors in a mouse model. The results are potentially important to understand cell signaling events that regulate the development of a class of rare ovarian tumors. ABSTRACT: Ovarian granulosa cell tumors (GCTs) are rare sex cord-stromal tumors, accounting for ~5% ovarian tumors. The etiology of GCTs remains poorly defined. Genetically engineered mouse models are potentially valuable for understanding the pathogenesis of GCTs. Mice harboring constitutively active TGFβ signaling (TGFBR1-CA) develop ovarian GCTs that phenocopy several hormonal and molecular characteristics of human GCTs. To determine molecular alterations in the ovary upon TGFβ signaling activation, we performed transcriptomic profiling of gene expression associated with GCT development using ovaries from 1-month-old TGFBR1-CA mice and age-matched controls. RNA-sequencing and bioinformatics analysis coupled with the validation of select target genes revealed dysregulations of multiple cellular events and signaling molecules/pathways. The differentially expressed genes are enriched not only for known GCT-related pathways and tumorigenic events but also for signaling events potentially mediated by neuroactive ligand-receptor interaction, relaxin signaling, insulin signaling, and complements in TGFBR1-CA ovaries. Additionally, a comparative analysis of our data in mice with genes dysregulated in human GCTs or granulosa cells overexpressing a mutant FOXL2, the genetic hallmark of adult GCTs, identified some common genes altered in both conditions. In summary, this study has revealed the molecular signature of ovarian GCTs in a mouse model that harbors the constitutive activation of TGFBR1. The findings may be further exploited to understand the pathogenesis of a class of poorly defined ovarian tumors.