TAK-243 induces rapid ER stress and exhibits enhanced cytotoxicity compared with bortezomib. DLBCL cells were treated with TAK-243 or bortezomib. (A) Cells were lysed, and proteins were subjected to immunoblotting at the indicated time points. (B) Apoptosis was assessed after 24 hours by Annexin V staining. Data are presented as mean ± SE; *P < .05. (C-E) DLBCL cell lines were treated with TAK-243 or bortezomib. Cells were then subjected to immunoblotting. (F) OCI-LY3 cells were treated with 1000 nM TAK-243, 1000 nM bortezomib, or vehicle control for 4 hours and stained for LC3 (green) and 4′,6-diamidino-2-phenylindole (blue). Original magnification ×500.