Given the important role that inhibitory kappa B (IκB) kinase β (IKKβ) plays in pancreatic cancer (PC) development and progression, inhibitors targeting IKKβ are believed to be increasingly popular as novel anti-PC therapies. Two synthetic molecules, named EF24 and EF31, exhibited favorable potential in terms of inhibition of both IKKβ activity and PC cell proliferation. Aiming to enhance their cellular efficacy and to analyze their structure–activity relationship, four series of EF24 and EF31 analogs were designed and synthesized. Through kinase activity and vitality screening of cancer cells, D6 displayed excellent inhibition of both IKKβ activity and PC cell proliferation. Additionally, multiple biological evaluations showed that D6 was directly bound to IKKβ and significantly suppressed the activation of the IKKβ/nuclear factor κB pathway induced by tumor necrosis factor-α, as well as effectively inducing cancer cell apoptosis. Moreover, molecular docking and molecular dynamics simulation analysis indicated that the dominant force between D6 and IKKβ comprised hydrophobic interactions. In conclusion, D6 may be a promising therapeutic agent for PC treatment and it also provides a structural lead for the design of novel IKKβ inhibitors.
EF24 is an IKKβ inhibitor (IC 50 : 72 μM) containing various anti-tumor activities. In this study, a series of EF24 analogs targeting IKKβ were designed and synthesized. Several IKKβ inhibitors with better activities than EF24 were screened out and B3 showed best IKKβ inhibitory (IC 50 : 6.6 μM). Molecular docking and dynamic simulation experiments further confirmed this inhibitory effect. B3 obviously suppressed the viability of Hela229, A549, SGC-7901 and MGC-803 cells. Then, in SGC-7901 and MGC-803 cells, B3 blocked the NF-κB signal pathway by inhibiting IKKβ phosphorylation, and followed arrested the cell cycle at G2/M phase by suppressing the Cyclin B1 and Cdc2 p34 expression, induced the cell apoptosis by down-regulating Bcl-2 protein and up-regulating cleaved-caspase3. Moreover, B3 significantly reduced tumor growth and suppressed the IKKβ-NF-κB signal pathway in SGC-7901 xenograft model. In total, this study present a potential IKKβ inhibitor as anti-tumor precursor.
As NF-κB signaling pathway is constitutively activated in lung cancer, targeting NF-κB has a potential for the treatment. EF24 has been proved to be a NF-κB inhibitor with good antitumor activity, while whose toxicity possibly became one of the obstacles to enter into clinical application. In order to find high efficiency and low toxicity NF-κB inhibitors, EF24 was modified and 13d was screened out. It was proved that 13d possessed an effective combination of inhibiting NF-κB pathway and showing lower cytotoxicity on normal cells as well as less toxicity in acute toxicity experiment compared with the lead compound of EF24. In addition, 13d was found to inhibit cell vitality, arrest cell cycle in G2/M phase, promote cell apoptosis, and suppress the xenograft tumor growth. Furthermore, 13d was elucidated to induce pyroptosis developing from apoptosis, which was associated with the inhibition of NF-κB. Taken together, it was suggested that 13d was a potent antitumor agent.