Inhibition of Akt induces significant downregulation of survivin and cytotoxicity in human multiple myeloma cells

• Published in: British journal of haematology Vol. 138; no. 6; pp. 783 - 791
• Main Authors: Hideshima, Teru, Catley, Laurence, Raje, Noopur, Chauhan, Dharminder, Podar, Klaus, Mitsiades, Constantine, Tai, Yu‐Tzu, Vallet, Sonia, Kiziltepe, Tanyel, Ocio, Enrique, Ikeda, Hiroshi, Okawa, Yutaka, Hideshima, Hiromasa, Munshi, Nikhil C., Yasui, Hiroshi, Richardson, Paul G., Anderson, Kenneth C.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.09.2007; Blackwell
• Subjects: Akt; Animals; Apoptosis - drug effects; Biological and medical sciences; Boronic Acids - therapeutic use; Bortezomib; Cell Line, Tumor; Cell Proliferation - drug effects; Down-Regulation; Hematologic and hematopoietic diseases; Humans; Immunodeficiencies. Immunoglobulinopathies; Immunoglobulinopathies; Immunopathology; Inhibitor of Apoptosis Proteins; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Medical sciences; Mice; Microtubule-Associated Proteins - genetics; Microtubule-Associated Proteins - metabolism; Models, Animal; multiple myeloma; Multiple Myeloma - drug therapy; Multiple Myeloma - metabolism; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; Neoplasm Transplantation; Perifosine; Phosphorylcholine - analogs & derivatives; Phosphorylcholine - pharmacology; Phosphorylcholine - therapeutic use; Protease Inhibitors - therapeutic use; Proto-Oncogene Proteins c-akt - antagonists & inhibitors; Pyrazines - therapeutic use; RNA Interference; RNA, Small Interfering - pharmacology; survivin; Transplantation, Heterologous; β‐catenin; Antineoplastic agent; Human; Immunopathology; multiple myeloma; Hematology; Perifosine; Akt protein kinase; Cytotoxicity; Malignant hemopathy; Survivin; Akt; Myeloma; β-catenin; Immunoglobulinopathy; Apoptosis inhibitory protein; Lymphoproliferative syndrome; β Catenin; Inhibitor
• ISSN: 0007-1048; 1365-2141
• DOI: 10.1111/j.1365-2141.2007.06714.x

Summary Akt mediates growth and drug resistance in multiple myeloma (MM) cells in the bone marrow (BM) microenvironment. We have shown that a novel Akt inhibitor Perifosine induces significant cytotoxicity in MM cells in the BM milieu. This study further delineated molecular mechanisms whereby Perifosine triggered cytotoxicity in MM cells. Neither the intensity of Jun NH2‐terminal kinase phosphorylation nor caspase/poly (ADP‐ribose) polymerase cleavage correlated with Perifosine‐induced cytotoxicity in MM.1S, INA6, OPM1 and OPM2 MM cells. However, survivin, which regulates caspase‐3 activity, was markedly downregulated by Perifosine treatment, without changes in other anti‐apoptotic proteins. Downregulation of survivin by siRNA significantly inhibited OPM1 MM cell growth, confirming that survivin mediates MM cell survival. Perifosine significantly downregulated both function and protein expression of β‐catenin. Co‐culture with BM stromal cells (BMSCs) upregulated both β‐catenin and survivin expression in MM cells, which was blocked by Perifosine. Importantly, Perifosine treatment also downregulated survivin expression in human MM cells grown in vivo in a severe combined immunodeficient mouse xenograft model. Finally, Perifosine inhibited bortezomib‐induced upregulation of survivin, associated with enhanced cytotoxicity of combined bortezomib and Perifosine treatment. These preclinical studies provide the framework for clinical trials of bortezomib with Perifosine to improve patient outcome in MM.