Oral Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Role of the FOXL2 mutation in NF-κB signalling in adult granulosa cell tumour (#108)

Teharn Hegarty 1 , Simon Chu 1 , Peter Fuller 1
  1. Hudson Institute of Medical Research, Melbourne, VIC, Australia

Adult granulosa cell tumours (aGCT) are rare endocrine-related ovarian cancers. aGCT harbour a somatic FOXL2 gene mutation, where a cysteine is substituted for a tryptophan at amino acid 134 (C134W). The FOXL2C134W mutation is pathognomonic for aGCT.

The FOXL2C134W mutation-positive aGCT-derived KGN cell line, exhibits constitutively activated nuclear factor-kappaB (NF-κB) signalling implicated in cancer cell survival. Our previous studies have shown that inhibiting NF-κB signalling in KGN cells decreases proliferation and cell viability1. The relationship between the FOXL2C134W mutation and NF-κB signalling is unexplored.

This study seeks to understand the contribution of the FOXL2C134W mutation to aberrant NF-κB signalling.

CRISPR-Cas9 was used to repair the FOXL2 mutation in KGN cells. Proliferation was assessed using xCELLigence Real Time Cell Analysis. NF-κB transactivation was measured using dual luciferase assays in parental and FOXL2wt KGN cells. RNA sequencing was conducted on both cell lines, log2FC ≥1, Q value of <0.05 were considered significantly differentially expressed.

NF-κB transactivation was significantly decreased (p=0.02) in the FOXL2wt KGN cells compared to parental cells. Proliferation assays showed that FOXL2wt KGN cells had decreased proliferation compared to parental cells. Gene set enrichment analysis revealed significant enrichment (p<0.01) of NF-κB-regulated genes in response to TNF in FOXL2wt KGN cells compared to the parental cells. In the FOXL2wt KGN cells, 875 differentially expressed genes (DEGs) were identified, including 479 upregulated and 396 downregulated. DEGs within the NF-κB pathway include the upregulation of IKBE, an inhibitor of NF-κB.

This study found that repairing the FOXL2 mutation led to decreased NF-κB transactivation in KGN cells. The reversal of the mutation's effects on this cancer-associated pathway underscores its critical role in aGCT pathogenesis. These findings improve our understanding of aGCT biology and identifies the NF-κB pathway as a promising therapeutic target, potentially leading to better treatments for this rare but challenging cancer.

  1. 1. Chu, S., Nishi, Y., Yanase, T., Nawata, H., & Fuller, P.J. 2004. Transrepression of estrogen receptor beta signaling by nuclear factor-kappab in ovarian granulosa cells. Mol Endocrinol, 18:1919-28.