Bacosine triggers NRF2-TFEB-autophagy axis to attenuate arecoline-induced oxidative stress and inflammasome activation.

Arecoline, the principal constituent of areca nut, triggers oxidative stress and inflammasome activation, leading to chronic inflammation and oral cancer development. The aim of this study was to investigate the antioxidant and anti-inflammatory role of bacosine, a triterpenoid isolated from Bacopa monnieri, to counteract arecoline-induced oxidative and inflammatory responses in oral cancer cells. Our study revealed that bacosine induces NRF2 signalling to inhibit arecoline-induced reactive oxygen species (ROS) generation and inflammasome activation in oral cancer. Initially, our study identified that inhibition of the NRF2 pathway and its downstream antioxidant signalling drives excessive ROS accumulation during arecoline exposure. Bacosine restored NRF2 antioxidant signalling, leading to reduced intracellular ROS levels in arecoline-exposed cells. Additionally, bacosine triggers autophagy by upregulating autophagic regulators, ATG5 and BECLIN1, thereby enhancing lysosomal activity and promoting autophagic flux. Moreover, bacosine induces TFEB activation, linking antioxidant defence to autophagy induction in oral cancer cells. Likely, pharmacological inhibition (ML-385) and genetic silencing (siNRF2) of NRF2 diminished TFEB-induced autophagy during bacosine treatment. Interestingly, bacosine failed to attenuate arecoline-induced inflammasome activation in autophagy and TFEB-deficient cells, signifying that bacosine suppresses inflammasome activation through NRF2-TFEB-mediated autophagy. These findings underline bacosine as a promising therapeutic target for mitigating arecoline-induced oral pathologies and oral cancer.