Role of reactive oxygen species in brucein D-mediated p38-mitogen-activated protein kinase and nuclear factor-κB signalling pathways in human pancreatic adenocarcinoma cells

Abstract

BACKGROUND: In human pancreatic adenocarcinoma, nuclear factor-kappa-B (NF-kB) transcription factor is constitutively activated that contributes to the resistance of the tumour cells to induced apoptosis. In our earlier studies, we have shown that brucein D (BD) mediated apoptosis through activation of the p38-mitogen-activated protein kinase (MAPK) signalling pathway in pancreatic cancer cells. This study investigated the function of reactive oxygen species (ROS) in BD-mediated p38-MAPK and NF-kB signalling pathways in PANC-1 cells. METHODS: Glutathione and dihydroethidium assays were used to measure the antioxidant and superoxide levels, respectively. The protein expression of p22 phox , p67 phox and p38-MAPK were examined by western blot. The NF-kB activity was evaluated by electrophoretic mobility shift assay. RESULTS: Treatment with BD depleted the intracellular glutathione levels in PANC-1 cells. Brucein D triggered the activation of NADPH oxidase isoforms, p22 phox and p67 phox while enhancing the generation of superoxide. Increases in both intracellular ROS and NADPH oxidase activity were inhibited by an antioxidant, N-acetylcysteine (NAC). Brucein D-mediated activation of p38-MAPK was also inhibited by NAC. However, inhibition of NF-kB activity in BD-treated cells was independent of ROS. In vivo studies showed that BD treatment effectively reduced the rate of xenograft human pancreatic tumour in nude mice with no significant toxicity. CONCLUSION: These data suggest that BD is an apoptogenic agent for pancreatic cancer cells through activation of the redox-sensitive p38-MAPK pathway and inhibition of NF-kB anti-apoptotic activity in pancreatic cancer cells.

The relevance of Nrf2 pathway and autophagy in pancreatic cancer cells upon stimulation of reactive oxygen species

“…P62 works to sequester Keap1 into the autophagosomes, inhibiting the ubiquitylation of Nrf2, resulting in the noncanonical activation of Nrf2 [19][20][21]. Many studies have shown that cancer cells accumulate more reactive oxygen species (ROS) than normal cells [22,23]. Consistent with other researchers, we found that the level of ROS in pancreatic cancer cells had elevated along with the increasing metastatic ability [24].…”

The Quassinoid Isobrucein B Reduces Inflammatory Hyperalgesia and Cytokine Production by Post-transcriptional Modulation

“…These apparent contradictory effects of 1 compared to other quassinoids, such as brucein D 25 and quassinoids isolated from Eurycoma longifolia, 26 are very probably dependent upon Mice were pretreated sc with vehicle or 1 (0.5, 1, and 5 mg/ kg) 1 h before intraplantar injection of carrageenan. Three hours after carrageenan injection plantar tissues were collected for quantification of neutrophil migration by MPO activity.…”

Mechanisms of Superoxide Signaling in Epigenetic Processes: Relation to Aging and Cancer

“…This is typical for prostate cells [17][18][19][20][21][22][23][24][25], pancreatic cancer cells [26][27][28][29][30][31][32][33], melanoma cells [34][35], breast cancer cells [36][37][38][39], and other cancer cells [40][41][42][43][44][45][46][47][48][49][50]. It is important that the elevated ROS formation in cancer cells can have both surviving and hindering effects.…”