The combination therapy induced ER stress and histone acetylation in renal cancer cells. The 48-hour treatment with the combination of panobinostat and bortezomib induced ER stress synergistically as indicated by the increased expression of GRP78, HSP70, ERp44, and Ero1-Lα (A). It also caused ubiquitinated protein accumulation in all the cell lines synergistically and enhanced histone and also α-tubulin acetylation in Caki-1 and ACHN cells. In 769-P cells, the combination enhanced the acetylation of α-tubulin but not that of histone (B). The dashed lines in the Caki-1 results in parts A and B indicate that the order of the bands has been rearranged from the original gel.