Discovery of novel NO-releasing celastrol derivatives with Hsp90 inhibition and cytotoxic activities

Abstract To develop multifunctional drugs, a series of celastrol/NO donor hybrids were designed, synthesized and evaluated. The detection of NO release amounts showed that the more NO of these hybrids released, the more tumor cells were inhibited. 11b , which released the highest level of NO in vitro , exhibited superior potency (IC 50  = 0.48 ± 0.06 μM) compared to the other compounds. Further pharmacological studies showed that 11b induced dysregulations of the Hsp90 clients (Akt and Cdk4), apoptosis, and cell cycle arrested at G 0 /G 1 phase against A549 cells. These results suggested that inhibition of Hsp90 and release of NO was synergistic in cancer cells. Overall, the NO-releasing capacity and the inhibition of Hsp90 pathway signaling might explain the potent anti-proliferative activities of these compounds.