Data from Neddylation Inhibition Activates the Extrinsic Apoptosis Pathway through ATF4–CHOP–DR5 Axis in Human Esophageal Cancer Cells

Abstract

<div>Abstract<p><b>Purpose:</b> Targeting the protein neddylation pathway has become an attractive anticancer strategy; however, the role of death receptor–mediated extrinsic apoptosis during treatment remained to be determined.</p><p><b>Experimental Design:</b> The activation of extrinsic apoptosis and its role in MLN4924 treatment of human esophageal squamous cell carcinoma (ESCC) were evaluated both <i>in vitro</i> and <i>in vivo</i>. The expression of the components of extrinsic apoptotic pathway was determined by immunoblotting analysis and downregulated by siRNA silencing for mechanistic studies.</p><p><b>Results:</b> Pharmaceutical or genetic inactivation of neddylation pathway induced death receptor 5 (DR5)–mediated apoptosis and led to the suppression of ESCC in murine models. Mechanistically, neddylation inhibition stabilized activating transcription factor 4 (ATF4), a Cullin-Ring E3 ubiquitin ligases (CRL) substrate. Transcription factor CHOP was subsequently transactivated by ATF4 and further induced the expression of DR5 to activate caspase-8 and induce extrinsic apoptosis. Moreover, the entire neddylation pathway was hyperactivated in ESCC and was negatively associated with patient overall survival.</p><p><b>Conclusions:</b> Our findings highlight a critical role of ATF4–CHOP–DR5 axis-mediated extrinsic apoptosis in neddylation-targeted cancer therapy and support the clinical investigation of neddylation inhibitors (e.g., MLN4924) for the treatment of ESCC, a currently treatment-resistant disease with neddylation hyperactivation. <i>Clin Cancer Res; 22(16); 4145–57. ©2016 AACR</i>.</p></div>