Friday, January 26, 2018

Helenalin Analogues Targeting NF-κB p65: Thiol Reactivity and Cellular Potency Studies of Varied Electrophiles Authors

Dr. John C. Widen, Dr. Aaron M. Kempema, Jordan W. Baur, Hannah M. Skopec, Jacob T. Edwards, Tenley J. Brown, Dr. Dennis A. Brown, Dr. Frederick A. Meece, Prof. Daniel A. Harki

Helenalin is a pseudoguaianolide natural product that targets Cys38 within the DNA binding domain of NF-κB transcription factor p65 (RelA). Helenalin contains two Michael acceptors that covalently modify cysteines: a α-methylene-γ-butyrolactone and a cyclopentenone. We recently reported two simplified helenalin analogues that mimic the biological activity of helenalin and contain both electrophilic moieties. To determine the individual contributions of the Michael acceptors toward NF-κB inhibition, we synthesized a small library of helenalin-based analogues containing various combinations of α-methylene-γ-butyrolactones and cyclopentenones. The kinetics of thiol addition to a subset of the analogues was measured to determine the relative thiol reactivities of the embedded electrophiles. Additionally, the cellular NF-κB inhibitory activities of the analogues were determined to elucidate the contributions of each Michael acceptor to biological potency. Our studies suggest the α-methylene-γ-butyrolactone contributes most significantly to the NF-κB inhibition of our simplified helenalin analogues.


Oncogenic KRAS G12C: Kinetic and Redox Characterization of Covalent Inhibition

Minh V. Huynh, Derek Parsonage, Tom E. Forshaw, Venkat R. Chirasani, G. Aaron Hobbs, Hanzhi Wu, Jingyun Lee, Cristina M. Furdui, Leslie B. P...