The natural aporphine alkaloids including crebanine (CN), O-methylbulbocapnine (OMP), and dicentrine (DC), and protoberberine alkaloids, tetrahydropalmatine (THP) and N-methyl tetrahydropalmatine (NTHP), have been found in Stephania venosa. Previous reports demonstrated CN and THP exhibited anti-inflammatory properties. In this study, we investigated anti-inflammatory effect of CN analogs including OMP, DC, THP, and NTHP in RAW264.7 macrophages. The pre-treatment of macrophages with CN, OMP and DC suppressed lipopolysaccharide (LPS)-induced pro-inflammatory cytokines and mediators including interleukin-6 (IL-6), tumor necrosis factor alpha, prostaglandin E2 and nitric oxide, in which the rank-order of inhibitory potency was DC>CN≥OMP. Whereas, high dose THP (30-40 µg/mL) reduced LPS-induced IL-6 production in RAW264.7 cells but NTHP did not effect. Moreover, CN, OMP and DC inhibited the LPS-induced expression of inducible nitric oxide synthase and cyclooxygenase-2. OMP and DC inhibited LPS-induced nuclear factor kappa B (NF-κB) activation by suppressing the phosphorylation of NF-κB at Ser536, but not the nucleus translocation and inhibitor of kappaB (IκB)-α degradation. In addition, OMP and DC also reduced the phosphorylation and nucleus translocation of activator protein-1 (AP-1). Furthermore, OMP and DC suppressed the LPS-activated myeloid differentiation factor 88 (MyD88), Akt and mitogen-activated protein kinases (MAPKs) signaling pathway, which were the upstream signaling regulators of AP-1 and NF-κB. Collectively, OMP and DC have an anti-inflammatory effect on RAW264.7 macrophages by the suppression of pro-inflammatory cytokines and mediators. The inhibitory property of OMP and DC is mediated by blockage the activation of MyD88, MAPKs, Akt, NF-κB and AP-1 signaling molecules.
Numerous studies have indicated that tumor necrosis factor-alpha (TNF-α) could induce cancer cell survival and metastasis via activation of transcriptional activity of NF-κB and AP-1. Therefore, the inhibition of TNF-α-induced NF-κB and AP-1 activity has been considered in the search for drugs that could effectively treat cancer. Dicentrine, an aporphinic alkaloid, exerts anti-inflammatory and anticancer activities. Therefore, we investigated the effects of dicentrine on TNF-α-induced tumor progression in A549 lung adenocarcinoma cells. Our results demonstrated that dicentrine effectively sensitizes TNF-α-induced apoptosis in A549 cells when compared with dicentrine alone. In addition, dicentrine increases caspase-8, -9, -3, and poly (ADP-ribose) polymerase (PARP) activities by upregulating the death-inducing signaling complex and by inhibiting the expression of antiapoptotic proteins including cIAP2, cFLIP, and Bcl-XL. Furthermore, dicentrine inhibits the TNF-α-induced A549 cells invasion and migration. This inhibition is correlated with the suppression of invasive proteins in the presence of dicentrine. Moreover, dicentrine significantly blockes TNF-α-activated TAK1, p38, JNK, and Akt, leading to reduced levels of the transcriptional activity of NF-κB and AP-1. Taken together, our results suggest that dicentrine could enhance TNF-α-induced A549 cell death by inducing apoptosis and reducing cell invasion due to, at least in part, the suppression of TAK-1, MAPK, Akt, AP-1, and NF-κB signaling pathways.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.