Anti-Inflammatory Effect of Protopine through MAPK and NF-κB Signaling Regulation in HepG2 Cell

Protopine is a substance used for hemostasis with an anti-inflammatory action and is one of the substances that are actively undergoing experiments to confirm their utility as anticancer agents. This study examined the molecular changes in the cellular signaling pathways associated with inflammatory responses in phorbol 12-myristate 13 acetate (PMA)-induced human hepatocellular carcinoma cell line (Hep G2). The inhibition of PMA-induced phosphorylation of I-κB in HepG2, the effect of protopine on the MAPK signals, the inhibition of COX-2 activity, and the inhibition of MMP-9 as a medium of inflammatory response were evaluated by Western blot and qPCR. The effect of protopine on the survival rates in HepG2 cells was evaluated and found to be stable to a processing concentration of up to 40μM. Subsequent Western blot analyses showed that protopine blocks the transfer of the MAPKs cell signals induced by PMA and the transfer of the subunit of the nuclear factor-kappa B (NF-κB) to the nucleolus. Protopine inhibited the kappa alpha (I-κBα) phosphorylation in the cytosol and blocked PMA-induced inflammation via COX-2 activity inhibition. The expression of MMP-9 at the gene and protein levels, which is associated with cell migration and metastasis, was reduced by protopine.