Background
Granulosa cell tumours (GCT) are a rare ovarian cancer, accounting for 5% of ovarian cancer cases. The majority (95%) are adult GCT (aGCT), characterised by the heterozygous FOXL2 C134W mutation. While curable at early stages, aGCT have a propensity for late and aggressive recurrence, with no reliable prognostic markers. Current treatments, adapted from epithelial ovarian cancer regimens, offer limited benefit, resulting in an approximately 80% mortality rate in advanced/recurrent disease. Therefore, it is critical to understand aGCT pathogenesis to develop new potential therapeutic options for recurrent aGCT.
Our preliminary research identified constitutive activation of key transcription factors, NF-κB and AP-1, in aGCT. Moreover, X-linked inhibitor of apoptosis protein (XIAP), regulated by NF-κB, is overexpressed in GCT, and forms a feedback loop influencing NF-κB and AP-1 pathways by activating transforming growth factor beta-activated kinase 1 (TAK1). TAK1, interacts with the transforming growth factor beta-activated kinase 1 binding proteins (TAB1,2&3), collectively known as the TAK-TAB protein complex. We investigated the therapeutic potential of a TAK1 inhibitor (takinib), as a promising treatment for GCT.
Methods
We treated the aGCT-derived cell line, KGN, and transformed normal granulosa cell line, hGrC1, with serial concentrations of takinib for 48 hours. Cell proliferation was assessed using MTS assays and xCELLigence® RTCA. We determined the IC50 values for takinib in both cell lines and subsequently performed RNA-seq analysis.
Results
We observed significant reduction of cell proliferation in both cell lines over 24 and 48 hours after treating with takinib, especially with 7.5µM or higher concentrations. Moreover, KGN cells displayed higher sensitivity to takinib (IC50 4.5µM) compared to hGrC1 cells (IC50 ~7µM). Moreover, RNA-seq identified 141 differentially expressed genes in KGN-treated cells versus 8 in hGrC1-treated cells compared to controls (fold change >=2, q value <=0.05).
Conclusion
Takinib effectively inhibited cell proliferation in KGN cells compared to hGrC1 cells, suggesting the potential of targeting the NF-κB and AP-1 pathways via the TAK-TAB complex in GCT. Our ongoing research focuses on understanding cell death mechanisms and validating key regulatory molecules from RNA-seq data. This project aims to uncover the molecular mechanisms underlying aGCT pathogenesis and identify promising treatment strategies.