Mechanistic Insight into the Autophagic and Apoptotic Activity of Kaempferol on Liver Cancer Cells

Background: The accumulation of poorly folded protein in the endoplasmic reticulum (ER) promotes ER stress and contributes to the pathogenesis of hepatocellular carcinoma (HCC). Current therapies have various adverse effects, therefore, laying the need for an alternative approach. Kaempferol (KP), a naturally occurring flavonoid, possesses potent anti-proliferative properties against various cancer cells. Nevertheless, its involvement in HCC remains relatively unexplored, particularly regarding its influence on apoptosis and autophagy pathways.
Methods: The effect of KP on cell viability, and motility of Hep3B cells was evaluated by MTT, and scratch assay, respectively. Hoechst staining and FACS analysis were done to check the effect of KP on apoptosis and cell cycle progression. qRTPCR was used to evaluate the expression of several apoptosis and autophagy-related genes. KP was docked with several ER stress-related proteins involved in HCC to gain further insights into molecular mechanisms. The results of docking studies were validated with MD simulation and in vitro studies.
Results: Treatment with KP at different time intervals showed dose- and time-dependent growth inhibition of liver cancer cells. KP decreased motility and arrested the cell cycle at the G0/G1 phase in Hep3B cells. Additionally, in the context of HCC, the relationship between KP, apoptosis, and autophagy is significant. It induced apoptosis and autophagy in Hep3B cells by downregulating the expression of Bcl-2 and upregulated Bax and Bid, Caspase-3, Beclin-1, and LC3. KP showed a better binding affinity with Nrf2, PERK, and IRE1α among all selected proteins. Further, it reversed the protective effect of 4-PBA (ER Stress inhibitor) by inducing apoptosis and autophagy in Hep3B cells.
Conclusion: The study suggested KP as a potential chemopreventive agent for managing HCC by effectively inducing apoptosis and autophagy in Hep3B cells.