title: Concomitant downregulation of proliferation/survival pathways dependent on FGF-R3, JAK2 and BCMA in human multiple myeloma cells by multi-kinase targeting.
abstract: The identification of proliferation/survival pathways constitutively activated by genetic alterations in multiple myeloma (MM), or sustained by the bone marrow (BM) microenvironment, provides novel opportunities for the development of targeted therapies. The deregulated function of protein tyrosine kinases plays a critical role in driving MM malignant phenotype. We investigated the effects of the multi-target tyrosine kinase inhibitor RPI-1 in a panel of human MM cell lines, including t(4;14) positive cell lines expressing the TK receptor FGF-R3. Cells harboring FGF-R3 activating mutations (KMS11 and OPM2) displayed the highest sensitivity to RPI-1 antiproliferative effect. The stimulating effect of the aFGF ligand was abrogated in cells harboring a non-constitutively active receptor. Drug treatment inhibited activation and expression of the FGF-R3(Y373C) mutant as well as aFGF-dependent signaling involving AKT and ERKs. Inhibition of JAK2, an additional RPI-1 target, resulted in STAT3 inactivation. Blockade of these proliferation/survival pathways was associated with caspase-dependent apoptosis. Moreover, drug treatment abrogated proliferative and pro-invasive stimuli provided by conditioned medium from mesenchymal stromal cells. Gene expression profile of KMS11 cells showed 22 upregulated and 52 downregulated genes upon RPI-1 treatment, with an early modulation of genes implicated in MM pathobiology such as SAT-1, MYC, MIP-1alpha/beta, FGF-R3, and the growth factor receptor B-cell maturation antigen (BCMA). Thus, concomitant blockade of FGF-R3 and JAK2 results in inhibition of several MM-promoting pathways, including BCMA-regulated signaling, and downregulation of disease-associated proteins. These data may have therapeutic implications in the design of treatment strategies resulting in the concomitant inhibition of FGF-R3 and JAK2 signaling pathways in t(4;14) MM.
authors: Dipartimento di Oncologia Sperimentale e Medicina Molecolare, Fondazione IRCCS Istituto Nazionale dei Tumori, via Venezian 1, Milan, Italy.
authors: Giuliana
authors: G
authors: Cassinelli
authors: Domenica
authors: D
authors: Ronchetti
authors: Diletta
authors: D
authors: Laccabue
authors: Michela
authors: M
authors: Mattioli
authors: Giuditta
authors: G
authors: Cuccuru
authors: Enrica
authors: E
authors: Favini
authors: Valentina
authors: V
authors: Nicolini
authors: Angela
authors: A
authors: Greco
authors: Antonino
authors: A
authors: Neri
authors: Franco
authors: F
authors: Zunino
authors: Cinzia
authors: C
authors: Lanzi
mesh_terms: D017209:Apoptosis; D053301:B-Cell Maturation Antigen / Q000378:metabolism*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects* / Q000502:physiology; D015536:Down-Regulation; D020869:Gene Expression Profiling; D006801:Humans; D047468:Immunoprecipitation; D053614:Janus Kinase 2 / Q000378:metabolism*; D009101:Multiple Myeloma / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism*
chemical_list: D053301:B-Cell Maturation Antigen; D047428:Protein Kinase Inhibitors; D017468:Receptors, Fibroblast Growth Factor; C086966:TNFRSF17 protein, human; D053614:Janus Kinase 2