Molecular events underlying interleukin-6 independence in a subclone of the CMA-03 multiple myeloma cell line.

We explored the molecular mechanisms involved in the establishement of CMA-03/06, an IL-6-independent variant of the multiple myeloma cell line CMA-03 previously generated in our Institution. CMA-03/06 cells grow in the absence of IL-6 with a doubling time comparable with that of CMA-03 cells; neither the addition of IL6 (IL-6) to the culture medium nor co-culture with multipotent mesenchymal stromal cells increases the proliferation rate, although they maintain the responsiveness to IL-6 stimulation as demonstrated by STAT1, STAT3, and STAT5 induction. IL-6 independence of CMA-03/06 cells is not apparently due to the development of an autocrine IL-6 loop, nor to the observed moderate constitutive activation of STAT5 and STAT3, since STAT3 silencing does not affect cell viability or proliferation.

Transcriptional characterization of a prospective series of primary plasma cell leukemia revealed signatures associated with tumor progression and poorer outcome.

Purpose: Plasma cell leukemia (PCL) is a rare form of plasma cell dyscrasia that presents either as a progression of previously diagnosed multiple myeloma, namely secondary PCL, or as initial manifestation of disease, namely primary PCL (pPCL). Although the presenting signs and symptoms include those seen in multiple myeloma, pPCL is characterized by several aspects that define a more aggressive course. Here, we have investigated the transcriptome of pPCLs and correlated differential expression profiles with outcome to provide insights into the biology of the disease.

MicroRNAs in the pathobiology of multiple myeloma.

MicroRNAs (miRNAs) are small non-coding RNAs that bind to the 3'untranslated region of target mRNAs and lead to translation repression or mRNA degradation, thus regulating important cell processes. MiRNA deregulation has been identified in virtually all types of cancer, and miRNA profiling has proved useful in cancer diagnosis, prognosis and response to therapy. So far, limited but important evidence of miRNA impaired expression has been reported in multiple myeloma (MM), suggesting implications in the pathogenesis and biology of the disease.

The reconstruction of transcriptional networks reveals critical genes with implications for clinical outcome of multiple myeloma.

Purpose: The combined use of microarray technologies and bioinformatics analysis has improved our understanding of biological complexity of multiple myeloma (MM). In contrast, the application of the same technology in the attempt to predict clinical outcome has been less successful with the identification of heterogeneous molecular signatures. Herein, we have reconstructed gene regulatory networks in a panel of 1,883 samples from MM patients derived from publicly available gene expression sets, to allow the identification of robust and reproducible signatures associated with poor prognosis across independent data sets.

Identification of microRNA expression patterns and definition of a microRNA/mRNA regulatory network in distinct molecular groups of multiple myeloma.

To date, little evidence of miRNA expression/deregulation in multiple myeloma has been reported. To characterize miRNA in the context of the major multiple myeloma molecular types, we generated miRNA expression profiles of highly purified malignant plasma cells from 40 primary tumors. Furthermore, transcriptional profiles, available for all patients, were used to investigate the occurrence of miRNA/predicted target mRNA pair anticorrelations, and the miRNA and genome-wide DNA data were integrated in a subset of patients to evaluate the influence of allelic imbalances on miRNA expression.

Molecular targeting of the PKC-beta inhibitor enzastaurin (LY317615) in multiple myeloma involves a coordinated downregulation of MYC and IRF4 expression.

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.

The oral protein-kinase C beta inhibitor enzastaurin (LY317615) suppresses signalling through the AKT pathway, inhibits proliferation and induces apoptosis in multiple myeloma cell lines.

Deregulation of the protein kinase C (PKC) signalling pathway has been implicated in tumor progression. Here we investigated the PKC inhibitor enzastaurin for its activity against multiple myeloma (MM) cells. Enzastaurin suppresses cell proliferation in a large panel of human myeloma cell lines (HMCLs), with IC50 values ranging from 1.

Upregulation of translational machinery and distinct genetic subgroups characterise hyperdiploidy in multiple myeloma.

Karyotypic instability, including numerical and structural chromosomal aberrations, represents a distinct feature of multiple myeloma (MM). About 40-50% of patients display hyperdiploidy, defined by recurrent trisomies of non-random chromosomes. To molecularly characterise hyperdiploid (H) and nonhyperdiploid (NH) MM, we analysed the gene expression profiles of 66 primary tumours, and used fluorescence in situ hybridisation to investigate the major chromosomal alterations.

Integrative genomic analysis reveals distinct transcriptional and genetic features associated with chromosome 13 deletion in multiple myeloma.

Background And Objectives: The chromosome 13 deletion (Delta13) is one of the most frequent chromosomal alterations in multiple myeloma (MM). Delta13 is associated with an unfavorable prognosis, although there is increasing agreement that its prognostic relevance must be related to the ploidy status and the presence of different chromosomal translocations. The aim of this study was to provide a comprehensive analysis of the transcriptional features of Delta13 in MM.

Molecular characterization of human multiple myeloma cell lines by integrative genomics: insights into the biology of the disease.

To investigate the patterns of genetic lesions in a panel of 23 human multiple myeloma cell lines (HMCLs), we made a genomic integrative analysis involving FISH, and both gene expression and genome-wide profiling approaches. The expression profiles of the genes targeted by the main IGH translocations showed that the WHSC1/MMSET gene involved in t(4;14)(p16;q32) was expressed at different levels in all of the HMCLs, and that the expression of the MAF gene was not restricted to the HMCLs carrying t(14;16)(q32;q23). Supervised analyses identified a limited number of genes specifically associated with t(4;14) and involved in different biological processes.

Functional validation of the anaplastic lymphoma kinase signature identifies CEBPB and BCL2A1 as critical target genes.

Anaplastic large cell lymphomas (ALCLs) represent a subset of lymphomas in which the anaplastic lymphoma kinase (ALK) gene is frequently fused to the nucleophosmin (NPM) gene. We previously demonstrated that the constitutive phosphorylation of ALK chimeric proteins is sufficient to induce cellular transformation in vitro and in vivo and that ALK activity is strictly required for the survival of ALK-positive ALCL cells. To elucidate the signaling pathways required for ALK-mediated transformation and tumor maintenance, we analyzed the transcriptomes of multiple ALK-positive ALCL cell lines, abrogating their ALK-mediated signaling by inducible ALK RNA interference (RNAi) or with potent and cell-permeable ALK inhibitors.

Relevance of Ras gene mutations in the context of the molecular heterogeneity of multiple myeloma.

Ras gene mutations are a recurrent genetic lesion in multiple myeloma (MM). Here, we report a mutation analysis of N- and K-Ras genes in purified plasma cell populations from a panel of 81 newly diagnosed MM patients stratified according to the most frequent genetic and molecular features associated with the neoplasia. Ras gene mutations, mostly involving the N-Ras gene, were detected in 20% of the patients.

Molecular and biological characterization of three novel interleukin-6-dependent human myeloma cell lines.

Background And Objectives: Established human myeloma cell lines (HMCL) have significantly contributed to the investigation of the biological aspects of multiple myeloma. Our study reports the molecular and biological characterization of three novel interleukin-6 (IL-6)-dependent HMCL (CMA-01, CMA-02, CMA-03) established from the malignant plasma cells of myeloma patients with extramedullary disease.

Design And Methods: The immunophenotype, cell growth characteristics, IL-6 pathway, chromosomal alterations and gene expression profiles of the three HMCL were investigated.

Transcription repression activity is associated with the type I isoform of the MMSET gene involved in t(4;14) in multiple myeloma.

The WHSC1/MMSET gene, involved in t(4;14)(p16.3;q32) in multiple myeloma, encodes putative isoforms (MMSET I, MMSET II and RE-IIBP) which are thought to be involved in transcription regulation. We investigated their activity in transfected 293T and HeLa cells.

Molecular classification of multiple myeloma: a distinct transcriptional profile characterizes patients expressing CCND1 and negative for 14q32 translocations.

Purpose: The deregulation of CCND1, CCND2 and CCND3 genes represents a common event in multiple myeloma (MM). A recently proposed classification grouped MM patients into five classes on the basis of their cyclin D expression profiles and the presence of the main translocations involving the immunoglobulin heavy chain locus (IGH) at 14q32. In this study, we provide a molecular characterization of the identified translocations/cyclins (TC) groups.

Gene expression profiling of plasma cell dyscrasias reveals molecular patterns associated with distinct IGH translocations in multiple myeloma.

Multiple myeloma (MM) is the most common form of plasma cell dyscrasia, characterized by a marked heterogeneity of genetic lesions and clinical course. It may develop from a premalignant condition (monoclonal gammopathy of undetermined significance, MGUS) or progress from intramedullary to extramedullary forms (plasma cell leukemia, PCL). To provide insights into the molecular characterization of plasma cell dyscrasias and to investigate the contribution of specific genetic lesions to the biological and clinical heterogeneity of MM, we analysed the gene expression profiles of plasma cells isolated from seven MGUS, 39 MM and six PCL patients by means of DNA microarrays.

Characterization of oncogene dysregulation in multiple myeloma by combined FISH and DNA microarray analyses.

Chromosomal translocations involving the immunoglobulin heavy chain (IGH) locus and various partner loci frequently are associated with multiple myeloma (MM). We investigated the expression profiles of the FGFR3/MMSET, CCND1, CCND3, MAF, and MAFB genes, which are involved in t(4;14)(p16.3;q32), t(11;14)(q13;q32), t(6;14)(p21;q32), t(14;16)(q32;q23), and t(14;20)(q32;q12), respectively, in purified plasma cell populations from 39 MMs and six plasma cell leukemias (PCL) by DNA microarray analysis and compared the results with the presence of translocations as assessed by dual-color FISH or RT-PCR.

Heterogeneous pattern of chromosomal breakpoints involving the MYC locus in multiple myeloma.

Chromosomal rearrangements of the MYC locus, which often involve the IG loci, are recurrent events in multiple myeloma (MM) and plasma cell leukemia (PCL). We used dual-color fluorescence in situ hybridization (FISH) to characterize the breakpoint locations of chromosomal translocations/rearrangements involving the MYC locus at 8q24 found in a panel of 14 MM cell lines and 70 primary tumors (66 MM and 4 PCL). MYC locus alterations were observed in 21 cases: MYC/IG (mainly IGH@) fusions in 11 cell lines and three patients (2 MM and 1 PCL), and extra signals and/or abnormal MYC localizations in seven patients (5 MM and 2 PCL).