title: The novel orally bioavailable inhibitor of phosphoinositol-3-kinase and mammalian target of rapamycin, NVP-BEZ235, inhibits growth and proliferation in multiple myeloma.
abstract: NVP-BEZ235 is a new inhibitor of phosphoinositol-3-kinase (PI3 kinase) and mammalian target of rapamycin (mTOR) whose efficacy in advanced solid tumours is currently being evaluated in a phase I/II clinical trial. Here we show that NVP-BEZ235 inhibits growth in common myeloma cell lines as well as primary myeloma cells at nanomolar concentrations in a time and dose dependent fashion. Further experiments revealed induction of apoptosis in three of four cell lines. Inhibition of cell growth was mainly due to inhibition of myeloma cell proliferation, as shown by the BrdU assay. Cell cycle analysis revealed induction of cell cycle arrest in the G1 phase, which was due to downregulation of cyclin D1, pRb and cdc25a. NVP-BEZ235 inhibited phosphorylation of protein kinase B (Akt), P70S6k and 4E-BP-1. Furthermore we show that the stimulatory effect of CD40-ligand (CD40L), insulin-like growth factor 1 (IGF-1), interleukin-6 (IL-6) and conditioned medium of HS-5 stromal cells on myeloma cell growth is completely abrogated by NVP-BEZ235. In addition, synergism studies revealed synergistic and additive activity of NVP-BEZ235 together with melphalan, doxorubicin and bortezomib. Taken together, inhibition of PI3 kinase/mTOR by NVP-BEZ235 is highly effective and NVP-BEZ235 represents a potential new candidate for targeted therapy in multiple myeloma.
authors.affiliation: Department of Hematology and Oncology Medizinische Klinik Innenstadt, Klinikum der Universität München, Germany. Philipp.Baumann@med.uni-muenchen.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Baumann
authors.forename: Sonja
authors.initials: S
authors.lastname: Mandl-Weber
authors.forename: Fuat
authors.initials: F
authors.lastname: Oduncu
authors.forename: Ralf
authors.initials: R
authors.lastname: Schmidmaier
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001897:Boronic Acids / Q000494:pharmacology; D000069286:Bortezomib; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004317:Doxorubicin / Q000494:pharmacology; D004357:Drug Synergism; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D008558:Melphalan / Q000494:pharmacology; D009101:Multiple Myeloma; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011719:Pyrazines / Q000494:pharmacology; D011804:Quinolines / Q000008:administration & dosage / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D001897:Boronic Acids; D000069286:Bortezomib; D018797:Cell Cycle Proteins; D004317:Doxorubicin; D007093:Imidazoles; D008558:Melphalan; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010750:Phosphoproteins; D011494:Protein Kinases; D051057:Proto-Oncogene Proteins c-akt; D011719:Pyrazines; D011804:Quinolines; D011994:Recombinant Proteins; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases; C087000:EIF4EBP1 protein, human; C546842:MTOR protein, human; C531198:dactolisib