Lopinavir-Ritonavir Combination Induces Endoplasmic Reticulum Stress and Kills Urological Cancer Cells

BACKGROUND/AIM: Induction of endoplasmic reticulum (ER) stress is a novel approach to cancer treatment. This study investigated the ability of the clinically feasible combination of the human immunodeficiency virus protease inhibitors lopinavir and ritonavir to induce ER stress killing urological cancer cells. MATERIALS AND METHODS: Renal cancer cells (769-P, 786-O) and bladder cancer cells (UMUC-3, T-24) were used to investigate the ability of the combination to induce ER stress and its mechanism of action. RESULTS: The combination inhibited the growth of both renal and bladder cancer cells synergistically by inducing ER stress. The combination-induced ER stress increased the expression of AMP-activated protein kinase and suppressed the mammalian target of rapamycin pathway. It also increased the expression of a tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor and thereby sensitized the cancer cells to TRAIL. CONCLUSION: The combination of lopinavir and ritonavir acts against urological cancer cells by inducing ER stress synergistically.