Complex Crystal Structure Determination of Hsp90(N)-NVP-AUY922 and In Vitro Anti-NSCLC Activity of NVP-AUY922

New targeted chemotherapy agents greatly improved five-year survival in NSCLC patients, but which were susceptible to drug resistance. NVP-AUY922, terminated in phase II clinical trials, exhibited promising anti-NSCLC (non-small-cell lung cancer) activity targeting to Hsp90(N) (heat shock protein), which demonstrated advantages in overcoming drug resistance as a broad-spectrum anti-cancer target. It was expected to develop novel anti-NSCLC drugs to overcome drug resistance by the structural optimization of NVP-AUY922. However, the absence of high-resolution complex crystal structure of Hsp90(N)-NVP-AUY922 blocked the way. Herein, 1.59 angstrom-resolution complex crystal structure of Hsp90(N)-NVP-AUY922 (PDB ID 6LTI) was successfully determined by X-ray diffraction. Meanwhile, there was a strong binding capability between NVP-AUY922 and its target Hsp90(N) verified by TSA (Delta Tm, -15.56 +/- 1.78 degrees C) and ITC (K-d, 5.10 +/- 2.10 nM). Results by the complex crystal structure, TSA and ITC verified that NVP-AUY922 well accommodated in the ATP-binding pocket of Hsp90(N) to disable the molecular chaperone activity of Hsp90. Therefore, NVP-AUY922 exhibited approving inhibitory activity on NSCLC cell line H1299 (IC50, 2.85 +/- 0.06 mu M) by inhibiting cell proliferation, inducing cell cycle arrest and promoting cell apoptosis. At the basis of the complex crystal structure and molecular interaction analysis, thirty-two new NVP-AUY922 derivatives were further designed, and among which twenty-eight new ones display enhanced binding force with Hsp90(N) by molecular docking evaluation. The results would promote anti-NSCLC new drug development to overcome drug resistance based on the lead compound NVP-AUY922.