Open Access

ARTICLE

Ritonavir Interacts With Belinostat to Cause Endoplasmic Reticulum Stress and Histone Acetylation in Renal Cancer Cells

Makoto Isono, Akinori Sato, Kazuki Okubo, Takako Asano, Tomohiko Asano

Department of Urology, National Defense Medical College, Tokorozawa, Saitama, Japan

Oncology Research 2016, 24(5), 327-335. https://doi.org/10.3727/096504016X14666990347635

Abstract

The histone deacetylase (HDAC) inhibitor belinostat increases the amount of unfolded proteins in cells by promoting the acetylation of heat shock protein 90 (HSP90), thereby disrupting its chaperone function. The human immunodeficiency virus protease inhibitor ritonavir, on the other hand, not only increases unfolded proteins by suppressing HSP90 but also acts as a proteasome inhibitor. We thought that belinostat and ritonavir together would induce endoplasmic reticulum (ER) stress and kill renal cancer cells effectively. The combination of belinostat and ritonavir induced drastic apoptosis and inhibited the growth of renal cancer cells synergistically. Mechanistically, the combination caused ER stress (evidenced by the increased expression of the ER stress markers) and also enhanced histone acetylation by decreasing the expression of HDACs. To our knowledge, this is the first study that showed a beneficial combined effect of belinostat and ritonavir in renal cancer cells, providing a framework for testing the combination in renal cancer patients.

---

Keywords

---