Antitumor effect of the human immunodeficiency virus protease inhibitor ritonavir: induction of tumor-cell apoptosis associated with perturbation of proteasomal proteolysis.

Ritonavir is an HIV protease inhibitor used in the therapy of HIV infection. Ritonavir has also been shown to inhibit the chymotrypsin-like activity of isolated 20S proteasomes. Here, we demonstrate that ritonavir, like classical proteasome inhibitors, has antitumoral activities.