The HIV-protease inhibitor nelfinavir has shown broad anticancer activity in various preclinical and clinical contexts. In patients with advanced, proteasome inhibitor (PD-refractory multiple... Show moreThe HIV-protease inhibitor nelfinavir has shown broad anticancer activity in various preclinical and clinical contexts. In patients with advanced, proteasome inhibitor (PD-refractory multiple myeloma, nelfinavir-based therapy resulted in 65% partial response or better, suggesting that this may be a highly active chemotherapeutic option in this setting. The broad anticancer mechanism of action of nelfinavir implies that it interferes with fundamental aspects of cancer cell biology. We combined proteome-wide affinity-purification of nelfinavir-interacting proteins with genome-wide CRISPR/Cas9-based screening to identify protein partners that interact with nelfinavir in an activity-dependent manner alongside candidate genetic contributors affecting nelfinavir cytotoxicity. Nelfinavir had multiple activity-specific binding partners embedded in lipid bilayers of mitochondria and the endoplasmic reticulum. Nelfinavir affected the fluidity and composition of lipid-rich membranes, disrupted mitochondria! respiration, blocked vesicular transport, and affected the function of membrane-embedded drug efflux transporter ABCB1, triggering the integrated stress response. Sensitivity to nelfinavir was dependent on ADIPOR2, which maintains membrane fluidity by promoting fatty acid desaturation and incorporation into phospholipids. Supplementation with fatty acids prevented the nelfinavir-induced effect on mitochondria! metabolism, drug-efflux transporters, and stress-response activation. Conversely, depletion of fatty acids/cholesterol pools by the FDA-approved drug ezetimibe showed a synergistic anticancer activity with nelfinavir in vitro. These results identify the modification of lipid-rich membranes by nelfinavir as a novel mechanism of action to achieve broad anticancer activity, which may be suitable for the treatment of PI-refractory multiple myeloma.Significance: Nelfinavir induces lipid bilayer stress in cellular organelles that disrupts mitochondrial respiration and transmembrane protein transport, resulting in broad anticancer activity via metabolic rewiring and activation of the unfolded protein response. Show less
Besse, L.; Besse, A.; Stolze, S.C.; Sobh, A.; Zaal, E.A.; Ham, A.J. van der; ... ; Driessen, C. 2021
The HIV-protease inhibitor nelfinavir has shown broad anti-cancer activity in various preclinical and clinical contexts. In patients with advanced, proteasome inhibitor (PI)-refractory multiple... Show moreThe HIV-protease inhibitor nelfinavir has shown broad anti-cancer activity in various preclinical and clinical contexts. In patients with advanced, proteasome inhibitor (PI)-refractory multiple myeloma (MM), nelfinavir-based therapy resulted in 65% partial response or better, suggesting that this may be a highly active chemotherapeutic option in this setting. The broad anti-cancer mechanism of action of nelfinavir implies that it interferes with fundamental aspects of cancer cell biology. We combined proteome-wide affinity-purification of nelfinavir-interacting proteins with genome-wide CRISPR/Cas9-based screening to identify protein partners that interact with nelfinavir in an activity-dependent manner alongside candidate genetic contributors affecting nelfinavir cytotoxicity. Nelfinavir had multiple activity-specific binding partners embedded in lipid bilayers of mitochondria and the endoplasmic reticulum. Nelfinavir affected the fluidity and composition of lipid-rich membranes, disrupted mitochondrial respiration, blocked vesicular transport, and affected the function of membrane-embedded drug efflux transporter ABCB1, triggering the integrated stress response. Sensitivity to nelfinavir was dependent on ADIPOR2, which maintains membrane fluidity by promoting fatty acid desaturation and incorporation into phospholipids. Supplementation with fatty acids prevented the nelfinavir-induced effect on mitochondrial metabolism, drug efflux transporters, and stress response activation. Conversely, depletion of fatty acids/cholesterol pools by the FDA-approved drug ezetimibe showed a synergistic anti-cancer activity with nelfinavir in vitro. These results identify the modification of lipid-rich membranes by nelfinavir as a novel mechanism of action to achieve broad anti-cancer activity, which may be suitable for the treatment of PI-refractory multiple myeloma. Show less
Venetoclax is an oral BCL2 inhibitor undergoing investigation for use in relapsed or refractory multiple myeloma (RRMM), particularly in combination with proteasome inhibitors (VPI)[1,2]. An... Show moreVenetoclax is an oral BCL2 inhibitor undergoing investigation for use in relapsed or refractory multiple myeloma (RRMM), particularly in combination with proteasome inhibitors (VPI)[1,2]. An interim analysis of a current phase 2 trial of venetoclax with carfilzomib in RRMM demonstrated an overall response rate of 78% with a very good partial response rate of 56%[3,4]. However, a separate ongoing phase 3 trial of venetoclax with bortezomib found a decrease in overall survival due to increased fatal infections in the venetoclax arm compared to placebo. Better describing these infections may give insight into the pathophysiology and prove useful in mitigating strategies for use with VPI therapy in RRMM. Show less
