West Asia Organization for Cancer Prevention (WAOCP), APOCP's West Asia Chapter. Asian Pacific Journal of Cancer Prevention 1513-7368 17 5 2016 05 01 Combination of Nimbolide and TNF--Increases Human Colon Adenocarcinoma Cell Death through JNK-mediated DR5 Up- regulation 2637 2641 32451 EN Chantana Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, Thailand Chavi Yenjai Prasert Reubroycharoen Pornthip Waiwut Journal Article 1970 01 01 Tumor necrosis factor (TNF-), an inflammatory cytokine that plays an important role in the control of cell proliferation, differentiation, and apoptosis, has previously been used in anti-cancer therapy. However, the therapeutic applications of TNF- are largely limited due to its general toxicity and anti-apoptotic influence. To overcome this problem, the present study focused on the effect of active constituents isolated from a medicinal plant on TNF--induced apoptosis in human colon adenocarcinoma (HT-29) cells. Nimbolide from Azadirachta indica was evaluated for cytotoxicity by methyl tetrazolium 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay and phase contrast microscopy. Effects on apoptotic signaling proteins were investigated using Western blot analysis. Nimbolide showed cytotoxicity against HT-29 cells that was significantly different from the control group (<0.01), a concentration of 10 M significantly inducing cell death (<0.01). In combination with TNF-, nimbolide significantly enhanced-induced cell death. In apoptotic pathway, nimbolide activated c-Jun N-terminal kinase (JNK) phosphorylation, BH3 interacting-domain death agonist (Bid) and up-regulated the death receptor 5 (DR5) level. In the combination group, nimbolide markedly sensitized TNF--induced JNK, Bid, caspase-3 activation and the up-regulation of DR5. Our findings overall indicate that nimbolide may enhance TNF--mediated cellular proliferation inhibition through increasing cell apoptosis of HT-29 cells by up-reglation of DR5 expression via the JNK pathway. https://journal.waocp.org/article_32451_56a676c870a172828d2bdcd1e42c20de.pdf