Activation of the c-Jun N-terminal Kinase/Activating Transcription Factor 3 (ATF3) Pathway Characterizes Effective Arylated Diazeniumdiolate-Based Nitric Oxide-Releasing Anticancer Prodrugs

Abstract

Improved therapies are needed for nonsmall cell lung cancer. Diazeniumdiolate-based nitric oxide (NO)-releasing prodrugs are a growing class of promising NO-based therapeutics. Recently, we have shown that O2-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K, 1) is effective against nonsmall cell lung cancer (NSCLC) cells in culture and in vivo. Here we report mechanistic studies with compound 1 and its homopiperazine analogue and structural modification of these into more stable prodrugs. Compound 1 and its homopiperazine analogue were potent cytotoxic agents against NSCLC cells in vitro and in vivo, concomitant with activation of the SAPK/JNK stress pathway and upregulation of its downstream effector ATF3. Apoptosis followed these events. An aryl-substituted analogue, despite extended half-life in the presence of glutathione, did not activate JNK or have antitumor activity. The data suggest that rate of reactivity with glutathione and activation of JNK/ATF3 are determinants of cancer cell killing by these prodrugs.