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/NFκB signaling 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-κB signaling pathways, were analyzed by qRT-PCR, immunoblotting and
ELISA. Expression profiling of noncoding RNAs (ncRNAs) that influence PI3K/Akt/NF-κB signaling 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 the activation of PI3K/Akt/NFκB signaling. 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 signaling.
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 mediated
by inhibiting key molecular players in the PI3K/Akt/NF-κB signaling axis. Long-term studies on the impact
of snus exposure on various cellular processes, signaling pathways, and the interplay between genetic and epigenetic
mechanisms are however warranted. The results of this investigation may contribute to the development
of protection against soft tissue changes induced by smokeless tobacco in the human oral cavity.