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Background & Aims: Constitutive activation of NF-κB is an important event involved in chronic inflammation in hepatocellular carcinoma (HCC). CPAP, which plays important roles in centrosomal functions, was previously identified as the transcriptional co-activator of NF-κB. However, the molecular mechanism is unclear. The goal of this study was to investigate the role of CPAP in activating the NF-κB pathway in HCC., Methods: SK-Hep1, HuH7, HepG2, HepG2X, Hep3B, and Hep3BX cells with CPAP overexpression or CPAP siRNA were used to evaluate activation of NF-κB under TNF-α stimulation by reporter assay, RT-PCR, Q-PCR, and Western blot analysis. In vivo SUMO modification of CPAP was demonstrated by an in situ PLA assay. Human HCC tissues were used to perform Q-PCR, Western blot, and IHC., Results: CPAP siRNA abolished the interaction between IKKβ and NF-κB, whereas overexpression of CPAP enhanced this interaction and finally led to augmented NF-κB activation by increasing the phosphorylation of NF-κB. CPAP could enter nuclei by associating with NF-κB. Furthermore, CPAP was SUMO-1 modified upon TNF-α stimulus, and this is essential for its NF-κB co-activator activity. SUMO-1-deficient CPAP mutant lost its NF-κB co-activator activity and failed to enter nuclei. Importantly, SUMOylated CPAP could synergistically increase the HBx-induced NF-κB activity., Conclusions: CPAP is essential for the recruitment of the IKK complex to inactivated NF-κB upon TNF-α treatment. Expression of CPAP was positively correlated with a poor prognosis in HBV-HCC. CPAP has the potential to serve as a therapeutic target for inflammation and inflammation-related diseases., (Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Morusin is a pure compound isolated from root bark of Morusaustralis (Moraceae). In this study, we demonstrated that morusin significantly inhibited the growth and clonogenicity of human colorectal cancer HT-29 cells. Apoptosis induced by morusin was characterized by accumulation of cells at the sub-G(1) phase, fragmentation of DNA, and condensation of chromatin. Morusin also inhibited the phosphorylation of IKK-alpha, IKK-beta and IkappaB-alpha, increased expression of IkappaB-alpha, and suppressed nuclear translocation of NF-kappaB and its DNA binding activity. Dephosphorylation of NF-kappaB upstream regulators PI3K, Akt and PDK1 was also displayed. In addition, activation of caspase-8, change of mitochondrial membrane potential, release of cytochrome c and Smac/DIABLO, and activation of caspase-9 and -3 were observed at the early time point. Downregulation in the expression of Ku70 and XIAP was exhibited afterward. Caspase-8 or wide-ranging caspase inhibitor suppressed morusin-induced apoptosis. Therefore, the antitumor mechanism of morusin in HT-29 cells may be via activation of caspases and inhibition of NF-kappaB.

The staphylococcal enterotoxins produced by Staphylococcus aureus are associated with pyrogenic response in humans and primates. This study investigates the role of NADPH oxidase and nuclear factor-kappa B (NF-kappaB) on enterotoxin staphylococcal enterotoxin C1 (SEC1)-induced pyrogenic cytokine production in human peripheral blood mononuclear cells (PBMC). The results indicate that the febrile response to the supernatant fluids of SEC1-stimulated PBMC in rabbits was in parallel with the levels of interleukin-1beta and interleukin-6 in the supernatants. The release of interleukin-1beta and interleukin-6, nuclear translocation of NF-kappaB and its DNA binding activity in the SEC1-stimulated PBMC were time-dependent and were completely eliminated by pyrrolidine dithiocarbamate or SN-50 (NF-kappaB inhibitors). The release of reactive oxygen species in the supernatants and translocation of the NADPH oxidase p47(phox) subunit to the plasma membrane of SEC1-stimulated PBMC were time-dependent. Administration of apocynin (NADPH oxidase inhibitor) attenuated the febrile response to the supernatants in rabbits and decreased the translocation of NADPH oxidase p47(phox) subunit and NF-kappaB activity in the SEC1-stimulated PBMC, and suppressed reactive oxygen species and pyrogenic cytokine production in the supernatants. Taken together, SEC1 may act through an NADPH oxidase mechanism to release reactive oxygen species, which activate NF-kappaB in PBMC to stimulate the synthesis of pyrogenic cytokines that trigger a fever response in rabbits.