Ovarian adult granulosa cell tumours (aGCT) are endocrine-related neoplasms that have a propensity for late and invasive recurrence with limited therapeutic options and high mortality (~80%). We previously identified constitutive activation of NF-kB and AP-1 signalling and overexpression of XIAP in aGCT. NF-kB regulates XIAP, forming a positive feed-forward loop activating both NF-kB and AP-1 via TAK1 (transforming growth factor beta-activated kinase 1). This study investigated TAK1 as a potential target, to inform therapeutic options for recurrent aGCT.
KGN (aGCT-derived cell line) and hGrC1 (transformed normal granulosa cell line) were treated with range of concentrations of Takinib, a specific TAK1 inhibitor. Cell proliferation was assessed using MTS assays and xCELLigence® RTCA. Using the IC50 of Takinib, we evaluated Caspase 3/7 activity using a Caspase 3/7 assay, and NF-kB and AP-1 transactivation using reporter assays. Additionally, RNA-seq analysis was performed.
Cell proliferation decreased significantly after Takinib treatment, with IC50 values of ~4.5µM for KGN cells and ~7µM for hGrC1 cells. NF-kB and AP-1 transactivation were reduced in KGN cells treated at the IC50 concentration of Takinib. Caspase 3/7 activity showed no difference between treated and control cells. RNA-seq analysis identified 141 differentially expressed genes (DEGs) after Takinib treatment in KGN cells, with 64 upregulated and 77 downregulated genes (fold changes >=2, Q value <0.05). The most common pathways associated with these changes were MAPK, TNF, and NF-kB. Only 8 DEGs were identified in treated hGrC1 cells compared to controls.
Takinib effectively reduced proliferation, NF-kB and AP-1 transactivation, and altered gene expression in KGN cells. Apoptosis is unlikely to be the cause of cell death due to the lack of caspase 3/7 activity after treatment; we are exploring a possible role for autophagy. These results suggest targeting NF-kB and AP-1 signalling pathways via TAK1 inhibition as a promising treatment for aGCT.