Publikation

Nelfinavir augments proteasome inhibition by bortezomib in myeloma cells and overcomes bortezomib and carfilzomib resistance

Wissenschaftlicher Artikel/Review - 01.03.2013

Bereiche
PubMed
DOI

Zitation
Kraus M, Bader J, Overkleeft H, Driessen C. Nelfinavir augments proteasome inhibition by bortezomib in myeloma cells and overcomes bortezomib and carfilzomib resistance. Blood Cancer J 2013; 3:e103.
Art
Wissenschaftlicher Artikel/Review (Englisch)
Zeitschrift
Blood Cancer J 2013; 3
Veröffentlichungsdatum
01.03.2013
eISSN (Online)
2044-5385
Seiten
e103
Kurzbeschreibung/Zielsetzung

HIV protease inhibitors (HIV-PI) are oral drugs for HIV treatment. HIV-PI have antitumor activity via induction of ER-stress, inhibition of phospho-AKT (p-AKT) and the proteasome, suggesting antimyeloma activity. We characterize the effects of all approved HIV-PI on myeloma cells. HIV-PI were compared regarding cytotoxicity, proteasome activity, ER-stress induction and AKT phosphorylation using myeloma cells in vitro. Nelfinavir is the HIV-PI with highest cytotoxic activity against primary myeloma cells and with an IC50 near therapeutic drug blood levels (8-14 μM), irrespective of bortezomib sensitivity. Only nelfinavir inhibited intracellular proteasome activity in situ at drug concentrations <40 μM. Ritonavir, saquinavir and lopinavir inhibited p-AKT comparable to nelfinavir, and showed similar synergistic cytotoxicity with bortezomib against bortezomib-sensitive cells. Nelfinavir had superior synergistic activity with bortezomib/carfilzomib in particular against bortezomib/carfilzomib-resistant myeloma cells. It inhibited not only the proteasomal β1/β5 active sites, similar to bortezomib/carfilzomib, but in addition the β2 proteasome activity not targeted by bortezomib/carfilzomib. Additional inhibition of β2 proteasome activity is known to sensitize cells for bortezomib and carfilzomib. Nelfinavir has unique proteasome inhibiting activity in particular on the bortezomib/carfilzomib-insensitive tryptic (β2) proteasome activity in intact myeloma cells, and is active against bortezomib/carfilzomib-resistant myeloma cells in vitro.