Apigenin enhances the cytotoxic effects of tumor necrosis factor-related apoptosis-inducing ligand in human rheumatoid arthritis fibroblast-like synoviocytes
- 255 Downloads
Activated rheumatoid arthritis (RA) fibroblast-like synoviocytes (RAFLSs) play a central role in both initiating and driving RA. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been documented to induce apoptosis only in a small proportion of RAFLSs, which is followed by an induction of proliferation in surviving cells. Apigenin, a chemopreventive bioflavonoid, exhibits proapoptotic activity in many types of cells. In the present study, we sought to determine whether apigenin could enhance the cytotoxic effect of TRAIL on activated RAFLSs. Human RAFLSs isolated from patients with RA were treated with TRAIL (1 nM), apigenin (20 μM), or their combination, and subjected to apoptosis analysis after a 24-h incubation and proliferation analysis after a 72-h incubation. Apoptosis assay revealed that TRAIL or apigenin alone induced a marked apoptosis in RAFLS and their combination yielded a synergistic increase in RAFLS apoptosis. Immunoblotting analysis of apoptosis regulators demonstrated that combined treatment with apigenin increased caspase-3 expression and activity and decreased the Bcl-2/Bax ratio relative to treatment with TRAIL alone. The presence of apigenin significantly restrained TRAIL-induced RAFLS proliferation, coupled with restoration of the expression of two cell-cycle inhibitors p21 and p27. Moreover, the combination with apigenin blunted TRAIL-induced activation of the phosphatidylinositol 3-kinase (PI3-K)/Akt pathway. Our data collectively demonstrate that apigenin sensitizes RAFLS to TRAIL-induced apoptosis and counteracts TRAIL-dependent RAFLS proliferation, which is likely mediated through inactivation of PI3-K/Akt signaling pathway.
KeywordsRheumatoid arthritis Fibroblast-like synoviocytes Apigenin Tumor necrosis factor-related apoptosis inducing ligand Akt Apoptosis Proliferation
This work was supported by the National Natural Science Foundation of China (31070747).
- 3.Lafyatis R, Remmers EF, Roberts AB, Yocum DE, Sporn MB, Wilder RL (1989) Anchorage-independent growth of synoviocytes from arthritic and normal joints. Stimulation by exogenous platelet-derived growth factor and inhibition by transforming growth factor-beta and retinoids. J Clin Invest 83:1267–1276PubMedCrossRefGoogle Scholar
- 14.Miyashita T, Kawakami A, Tamai M, Izumi Y, Mingguo H, Tanaka F, Abiru S, Nakashima K, Iwanaga N, Aratake K, Kamachi M, Arima K, Ida H, Migita K, Origuchi T, Tagashira S, Nishikaku F, Eguchi K (2003) Akt is an endogenous inhibitor toward tumor necrosis factor-related apoptosis inducing ligand-mediated apoptosis in rheumatoid synovial cells. Biochem Biophys Res Commun 312:397–404PubMedCrossRefGoogle Scholar
- 17.Perlman H, Nguyen N, Liu H, Eslick J, Esser S, Walsh K, Moore TL, Pope RM (2003) Rheumatoid arthritis synovial fluid macrophages express decreased tumor necrosis factor-related apoptosis-inducing ligand R2 and increased decoy receptor tumor necrosis factor-related apoptosis-inducing ligand R3. Arthritis Rheum 48:3096–3101PubMedCrossRefGoogle Scholar
- 18.Morel J, Audo R, Hahne M, Combe B (2005) Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces rheumatoid arthritis synovial fibroblast proliferation through mitogen-activated protein kinases and phosphatidylinositol 3-kinase/Akt. J Biol Chem 280:15709–15718PubMedCrossRefGoogle Scholar
- 21.Lu HF, Chie YJ, Yang MS, Lu KW, Fu JJ, Yang JS, Chen HY, Hsia TC, Ma CY, Ip SW, Chung JG (2010) Apigenin induces apoptosis in human lung cancer H460 cells through caspase- and mitochondria-dependent pathways. Hum Exp Toxicol 30(8):1053–1061. doi: 10.1177/0960327110386258 PubMedCrossRefGoogle Scholar
- 29.Lee JH, Zhou HY, Cho SY, Kim YS, Lee YS, Jeong CS (2007) Anti-inflammatory mechanisms of apigenin: inhibition of cyclooxygenase-2 expression, adhesion of monocytes to human umbilical vein endothelial cells, and expression of cellular adhesion molecules. Arch Pharm Res 30:1318–1327PubMedCrossRefGoogle Scholar
- 38.Trochon V, Blot E, Cymbalista F, Engelmann C, Tang RP, Thomaïdis A, Vasse M, Soria J, Lu H, Soria C (2000) Apigenin inhibits endothelial-cell proliferation in G(2)/M phase whereas it stimulates smooth-muscle cells by inhibiting P21 and P27 expression. Int J Cancer 85:691–696PubMedCrossRefGoogle Scholar