GADD34 Facilitates Cell Death Resulting from Proteasome Inhibition

Abstract

Background: Proteasome inhibition has been proven to be a promising therapeutic strategy in cancer clinical treatment. Inhibition of proteasome leads to failure of amino acid homeostasis, which causes cell death via activation of various mechanisms.

Materials and methods: To investigate the role of GADD34 in cell death following proteasome inhibition, we treated WT MEF and GADD34 KO MEF with MG132 and various analyses were performed, including PI staining, western blot, immunofluorescence and ROS production.

Results: Expression of GADD34 dramatically enhanced MG132-induced cell death via protein synthesis. GADD34 decreased phosphorylated eIF2α and increased ROS production and the levels of ubiquinated protein. Importantly, we found that accumulation of autophagy following MG132-treatment facilitated cell death in MEF.

Conclusion: GADD34 plays a vital role in promoting cell death following proteasome inhibition via enhancing protein synthesis to activate death-associated mechanisms, including ER stress, ROS production and autophagy formation.

Keywords: GADD34; autophagy; cell death; eIF2α; proteasome inhibition.