ATF4 and melanoma: To test the hypothesis of the involvement of Vx-809 in misfolding protein, we analyzed, through Western blotting analyses on cell lysates, the activation state of UPR signaling components, such as Grp78/BiP, ATF4 after inducing ER stress in adenocarcinomic human alveolar basal epithelial cells (A549), and malignant melanoma (A375).