title: Molecular targeting of the PKC-beta inhibitor enzastaurin (LY317615) in multiple myeloma involves a coordinated downregulation of MYC and IRF4 expression.
abstract: The protein kinase C (PKC) pathway has been shown to play a role in the regulation of cell proliferation in several haematological malignancies, including multiple myeloma (MM). Recent data have shown that a PKC inhibitor, enzastaurin, has antiproliferative and proapoptotic activity in a large panel of human myeloma cell lines (HMCLs). In order to further characterise the effect of enzastaurin in MM, we performed gene expression profiling of enzastaurin-treated KMS-26 cell line. We identified 62 upregulated and 32 downregulated genes that are mainly involved in cellular adhesion (CXCL12, CXCR4), apoptosis (CTSB, TRAF5, BCL2L1), cell proliferation (IGF1, GADD45A, BCMA (B-cell maturation antigen), CDC20), transcription regulation (MYC, MX11, IRF4), immune and defence responses. Subsequent validation by Western blotting of selected genes in four enzastaurin-treated HMCLs was consistent with our microarray analysis. Our data indicate that enzastaurin may affect important processes involved in the proliferation and survival of malignant plasma cells as well as in their interactions with the bone marrow microenvironment and provide a preclinical rationale for the potential role of this drug in the treatment of MM.
authors.affiliation: Department of Medical Sciences, Leukemia Study Center, University of Milano, and O.U. Hematology 1, Fondazione IRCCS Policlinico, Milano, Italy.
authors.forename: Donata
authors.initials: D
authors.lastname: Verdelli
authors.forename: Lucia
authors.initials: L
authors.lastname: Nobili
authors.forename: Katia
authors.initials: K
authors.lastname: Todoerti
authors.forename: Daniela
authors.initials: D
authors.lastname: Intini
authors.forename: Maria
authors.initials: M
authors.lastname: Cosenza
authors.forename: Monica
authors.initials: M
authors.lastname: Civallero
authors.forename: Jessika
authors.initials: J
authors.lastname: Bertacchini
authors.forename: Giorgio Lambertenghi
authors.initials: GL
authors.lastname: Deliliers
authors.forename: Stefano
authors.initials: S
authors.lastname: Sacchi
authors.forename: Luigia
authors.initials: L
authors.lastname: Lombardi
authors.forename: Antonino
authors.initials: A
authors.lastname: Neri