Wedelolactone induces pyroptosis to suppress retinoblastoma by inhibiting the Nrf2/Keap1 signaling pathway.

Background: Retinoblastoma is an intraocular malignancy with limited therapeutic options, imposing a severe health burden on young patients. Wedelolactone (WDL), a natural product from E. prostrata, possesses an anti-retinoblastoma activity, with the underlying regulatory mechanism remaining unknown.

Methods: Retinoblastoma cell lines and xenograft nude mouse models were treated with WDL and RTA-408, an agonist for nuclear factor-erythroid 2-related factor 2 (Nrf2). Western blotting was conducted to determine the protein expression levels of kelch-like ECH-associated protein 1 (Keap1) and Nrf2. We performed the cell counting kit-8 assay, the 5-ethynyl-2-deoxyuridine staining, and flow cytometry to detect cell viability, proliferation, and apoptosis, respectively. The tumor progression in vivo was evaluated via the measurement of volume, weight, and proliferation levels of solid tumors. Monosodium urate crystal was applied to activate pyroptosis which was assessed by the expression detection of pyroptosis-related indicators.

Results: WDL treatment elevated the expression of Keap1 and reduced the level of Nrf2. RTA-408 suppressed WDL-induced pyroptosis of retinoblastoma cells and reversed the effect of WDL on inhibiting retinoblastoma cell proliferation, promoting tumor cell apoptosis, and repressing the growth of solid tumors of the xenograft models. In addition, monosodium urate-induced pyroptosis partially restored the anti-retinoblastoma effect of WDL impaired by RTA-408.

Conclusion: WDL triggers pyroptosis by inhibiting the Nrf2/Keap1 signaling pathway to exert anti-retinoblastoma effects.