FXR activation suppresses NF-κB signaling, proliferation and migration in cervical cancer cells

The Farnesoid X receptor (FXR) is a nuclear receptor known for its role in inflammation regulation and tumor suppression in various cancers. However, its functional significance and underlying mechanisms in cervical cancer (CC) remain unclear. The persistent activation of the nuclear factor kappa B (NF-κB) signaling pathway due to inflammation is a key driver of cancer progression. This study investigates the effects of FXR activation in CC and its interaction with the NF-κB pathway.

CC cells were treated with GW4064, an FXR agonist (3 µM), and xenograft tumor models were assigned to receive 30 mg/kg GW4064. NF-κB-mediated transcriptional activity was assessed using a dual-luciferase reporter assay. Gene expression in CC cells and mouse tissues was analyzed via quantitative real-time polymerase chain reaction (qRT-PCR), while key proteins in the NF-κB and STAT3 signaling pathways were examined using Western blotting. Cell proliferation, migration, and invasion were evaluated through methylthiazolyldiphenyl-tetrazolium bromide (MTT), wound healing, and real-time cellular analysis (RTCA), respectively. Apoptosis was measured using a fluorescein isothiocyanate (FITC) Annexin V Apoptosis Detection Kit I.

FXR deletion in 6- to 8-week-old C57B/6 female mice led to abnormal upregulation of inflammatory genes in the cervix and aberrant NF-κB activation. Treatment with GW4064 suppressed NF-κB-regulated gene expression in Hela and Siha CC cells and inhibited NF-κB activity at the transcriptional level. Mechanistically, FXR activation suppressed tumor necrosis factor alpha (TNFα)-induced phosphorylation of NF-κB inhibitor alpha (IκBα) by directly binding to the promoter of inhibitor of nuclear factor kappa B kinase regulatory subunit gamma (IKBKG), thereby inhibiting its transcription. Additionally, FXR activation reduced CC cell proliferation and migration. In vivo, xenograft experiments in Hela cell-bearing Bagg's albino (BALB/c) nude female mice confirmed that FXR activation significantly suppressed tumor growth.

These findings highlight FXR activation as a potential therapeutic strategy for CC by targeting the NF-κB pathway as shown in both in vitro and in vivo.