Activation of PI3K/Akt/NF-kB signalling mediates Swedish Snus induced proliferation and apoptosis evasion in rat forestomach: Modulation by blueberry

BACKGROUND AND OBJECTIVES: The present study was undertaken to ascertain whether the modulatory effects of blueberries on cell proliferation induced by Swedish snus in the rat forestomach epithelium is mediated via abrogation of the PI3K/Akt/NFκβ signalling axis that regulates cell fate decision. METHODS: The transcript and protein expression of genes involved in cell cycle progression and apoptosis as well as canonical PI3K/Akt/NF-κβ signalling pathways were analysed by qRT-PCR, immunoblotting and ELISA. Expression profiling of noncoding RNAs (ncRNAs) that influence PI3K/Akt/NF-κβ signalling was undertaken. TUNEL assay was performed using flow cytometry. RESULTS: Administration of snus induced basal cell hyperplasia in the rat forestomach with increased cell proliferation and inhibition of apoptosis. This was associated with activation of PI3K/Akt/NFκB signalling. Coadministration of blueberries significantly suppressed snus-induced hyperplasia. Analysis of the molecular mechanisms revealed that blueberries suppress the phosphorylation of Akt, NF-κB and IKKβ, prevent nuclear translocation of NF-κB and modulate the expression of microRNAs that influence PI3K/Akt/NF-κB signalling. CONCLUSION: Taken together, the results of the current study provide compelling evidence that blueberries exert significant protective effects against snus-induced soft tissue changes in the rat forestomach epithelium that is mediated by inhibiting key molecular players in the PI3K/Akt/NF-κβ signalling axis. Long-term studies on the impact of snus exposure on various cellular processes, signalling pathways, and the interplay between genetic and epigenetic mechanisms are however warranted. The results from this investigation may contribute to the development of protection against soft tissue changes induced by smokeless tobacco in the human oral cavity.