SNX-2112, a selective Hsp90 inhibitor, potently inhibits tumor cell growth, angiogenesis, and osteoclastogenesis in multiple myeloma and other hematologic tumors by abrogating signaling via Akt and ERK.

Abstract

Heat-shock protein 90 (Hsp90) acts as a molecular chaperone required for maintaining the conformational stability of client proteins regulating cell proliferation, survival, and apoptosis. Here we investigate the biologic significance of Hsp90 inhibition in multiple myeloma (MM) and other hematologic tumors using an orally available novel small molecule inhibitor SNX-2112, which exhibits unique activities relative to 17-allyamino-17-demethoxy-geldanamycin (17-AAG). SNX-2112 triggers growth inhibition and is more potent than 17-AAG against MM and other malignancies. It induces apoptosis via caspase-8, -9, -3, and poly (ADP-ribose) polymerase cleavage. SNX-2112 inhibits cytokine-induced Akt and extracellular signal-related kinase (ERK) activation and also overcomes the growth advantages conferred by interleukin-6, insulin-like growth factor-1, and bone marrow stromal cells. Importantly, SNX-2112 inhibits tube formation by human umbilical vein endothelial cells via abrogation of eNOS/Akt pathway and markedly inhibits osteoclast formation via down-regulation of ERK/c-fos and PU.1. Finally, SNX-2112, delivered by its prodrug SNX-5422, inhibits MM cell growth and prolongs survival in a xenograft murine model. Our results indicate that blockade of Hsp90 by SNX-2112 not only inhibits MM cell growth but also acts in the bone marrow microenvironment to block angiogenesis and osteoclastogenesis. Taken together, our data provide the framework for clinical studies of SNX-2112 to improve patient outcome in MM and other hematologic malignancies.

• Authors: Yutaka Okawa, Teru Hideshima, Paul Steed, Sonia Vallet, Steven Hall, Ken Huang, John Rice, Amy Barabasz, Brianna Foley, Hiroshi Ikeda, Noopur Raje, Tanyel Kiziltepe, Hiroshi Yasui, Sotaro Enatsu, Kenneth C Anderson
• Journal: Blood (Blood) Vol. 113 Issue 4 Pg. 846-55 (Jan 22 2009) ISSN: 1528-0020 [Electronic] United States
• PMID: 18948577 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• HSP90 Heat-Shock Proteins
• Heterocyclic Compounds, 4 or More Rings
• Interleukin-6
• SNX 2112
• Insulin-Like Growth Factor I
• Proto-Oncogene Proteins c-akt
• Extracellular Signal-Regulated MAP Kinases

Topics

• Animals
• Cell Differentiation (drug effects)
• Cell Proliferation (drug effects)
• Cells, Cultured
• Extracellular Signal-Regulated MAP Kinases (metabolism)
• HSP90 Heat-Shock Proteins (antagonists & inhibitors, metabolism)
• Heterocyclic Compounds, 4 or More Rings (chemistry, pharmacology, therapeutic use)
• Humans
• Insulin-Like Growth Factor I (pharmacology)
• Interleukin-6 (pharmacology)
• Leukemia (drug therapy, metabolism, pathology)
• MAP Kinase Signaling System (drug effects)
• Mice
• Mice, SCID
• Molecular Structure
• Multiple Myeloma (blood supply, drug therapy, metabolism, pathology)
• Neovascularization, Pathologic (drug therapy)
• Osteoclasts (cytology, drug effects, metabolism)
• Proto-Oncogene Proteins c-akt (metabolism)
• Xenograft Model Antitumor Assays