Identification of genes modulated in multiple myeloma using genetically identical twin samples.

Genetic heterogeneity between individuals confounds the comparison of gene profiling of multiple myeloma (MM) cells versus normal plasma cells (PCs). To overcome this barrier, we compared the gene expression profile of CD138+ MM cells from a patient bone marrow (BM) sample with CD138+ PCs from a genetically identical twin BM sample using microarray profiling. Two hundred and ninety-six genes were up-regulated and 103 genes were down-regulated at least 2-fold in MM cells versus normal twin PCs.

Insights into the multistep transformation of MGUS to myeloma using microarray expression analysis.

To define specific pathways important in the multistep transformation process of normal plasma cells (PCs) to monoclonal gammopathy of uncertain significance (MGUS) and multiple myeloma (MM), we have applied microarray analysis to PCs from 5 healthy donors (N), 7 patients with MGUS, and 24 patients with newly diagnosed MM. Unsupervised hierarchical clustering using 125 genes with a large variation across all samples defined 2 groups: N and MGUS/MM. Supervised analysis identified 263 genes differentially expressed between N and MGUS and 380 genes differentially expressed between N and MM, 197 of which were also differentially regulated between N and MGUS.

The role of apoptosis-inducing receptors of the tumor necrosis factor family in thyroid cancer.

The tumor necrosis factor (TNF) family comprises several ligands, such as the prototype TNF-alpha, the Fas ligand (FasL) and TNF-related apoptosis-inducing ligand (TRAIL/Apo2L), which trigger apoptosis in susceptible cells by activating respective cell-surface receptors. The study of these cell death pathways has attracted significant attention in several fields, including that of thyroid cancer, because they participate in immune system function, as an arm of cell-mediated cytotoxicity, and because recombinant ligands are available for pharmacological use. TNF-alpha is a pluripotent cytokine that induces both pro-apoptotic and anti-apoptotic effects on thyroid carcinoma cells.

Hsp27 inhibits release of mitochondrial protein Smac in multiple myeloma cells and confers dexamethasone resistance.

Smac, second mitochondria-derived activator of caspases, promotes apoptosis via activation of caspases. Heat shock protein 27 (Hsp27) negatively regulates another mitochondrial protein, cytochrome c, during apoptosis; however, the role of Hsp27 in modulating Smac release is unknown. Here we show that Hsp27 is overexpressed in both dexamethasone (Dex)-resistant multiple myeloma (MM) cell lines (MM.

Endocrine/paracrine/autocrine survival factor activity of bone microenvironment participates in the development of androgen ablation and chemotherapy refractoriness of prostate cancer metastasis in skeleton.

Bone is the most frequent site of metastases of prostate cancer and is almost always the first and frequently the only site of metastases where disease will progress to stage D3. In addition, the number of skeletal metastatic foci is the most powerful independent prognostic factor of limited response to hormone ablation therapy and poor survival of patients with advanced prostate cancer. Furthermore, disease progression frequently occurs in the osteoblastic metastases, even though androgen ablation therapy still provides adequate and sustained control of disease at the primary site.

Novel biologically based therapies for Waldenstrom's macroglobulinemia.

Waldenstrom's macroglobulinemia (WM) remains an incurable B-cell malignancy, necessitating urgent development of novel treatment strategies. Building on our experience on bed-to-bedside translational studies for multiple myeloma (mm), we identified a constellation of novel classes of anti-WM agents, including the proteasome inhibitor PS-341; the ansamycin family of inhibitors (eg, geldanamycin and its analogues) of the heat-shock protein 90 (hsp90) molecular chaperone; histone deacetylase inhibitors, such as suberoylanilide hydroxamic acid (SAHA); and the thiazolidinedione group of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists (eg, ciglitazone or rosiglitazone). Our preclinical data show that these classes of agents induce growth arrest and apoptosis of WM cells, at concentrations relevant to those achieved in previous clinical uses of these drugs, and suggest that novel therapeutic strategies for WM can be designed to include combinations of these agents, to simultaneously target multiple levels of diverse pathways important for tumor cell growth and survival, and thus maximize the pro-apoptotic activities of these agents and/or neutralize protective responses of WM against their effects.

Expression of serotherapy target antigens in Waldenstrom's macroglobulinemia: therapeutic applications and considerations.

Monoclonal antibody (mAb) therapy (serotherapy) has been successfully used in the treatment of many B-cell malignancies, among them lymphoplasmacytic lymphoma, an uncommon disorder that includes patients with the clinicopathological diagnosis of Waldenstrom's macroglobulinemia (WM). Rituximab, a mAb directed at CD20, was recently demonstrated by us and others to induce remissions and facilitate hematological recovery in patients with WM. The expression of CD20, along with targets of other mAbs which are commercially available, currently in clinical trials, or in preclinical development, have not been extensively studied or well documented in lymphoplasmacytic lymphoma.

Proteomic analyses in Waldenstrom's macroglobulinemia and other plasma cell dyscrasias.

The proteomic analysis of tumor cells emerges as a key complement to gene expression profiling, primarily because regulation of protein expression (at the translational and post-translational levels) can buffer the magnitude of changes occurring at the gene transcription level, in order to fine tune cellular functions. Herein we describe the concept of proteomic analysis of the signaling state of tumor cells, as well as its application in the study of signaling pathways in plasma cell dyscrasias, such as Waldenstrom's macroglobulinemia (WM) and multiple myeloma (MM). Comparative studies of WM versus MM cells at baseline and in the setting of drug treatment reveals proteomic profiles of the signaling state with significant overlap (that could reflect a putative B-cell lineage-related proteomic signature), but also distinct differences, possibly associated with differential features in the biologic behavior and drug sensitivity of these diseases.

JNK-dependent release of mitochondrial protein, Smac, during apoptosis in multiple myeloma (MM) cells.

Smac, second mitochondria-derived activator of caspases, promotes apoptosis via activation of caspases. Previous studies have shown that c-Jun NH(2)-terminal kinase (JNK) is involved in regulating another mitochondrial protein, cytochrome c during apoptosis; however, the role of JNK in the release of mitochondrial Smac is unknown. Here we show that induction of apoptosis in multiple myeloma (MM) cells is associated with activation of JNK, translocation of JNK from cytosol to mitochondria, and release of Smac from mitochondria to cytosol.

Molecular sequelae of histone deacetylase inhibition in human malignant B cells.

Histone acetylation modulates gene expression, cellular differentiation, and survival and is regulated by the opposing activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDAC inhibition results in accumulation of acetylated nucleosomal histones and induces differentiation and/or apoptosis in transformed cells. In this study, we characterized the effect of suberoylanilide hydroxamic acid (SAHA), the prototype of a series of hydroxamic acid-based HDAC inhibitors, in cell lines and patient cells from B-cell malignancies, including multiple myeloma (MM) and related disorders.

Nuclear factor-kappaB p65 mediates tumor necrosis factor alpha-induced nuclear translocation of telomerase reverse transcriptase protein.

Sustained proliferation of cancer cells requires telomerase to maintain telomeres that regulate chromosomal stability and cellular mitosis. Expression of human telomerase reverse transcriptase (hTERT) catalytic subunit, which modulates telomerase activity, is regulated at both the transcriptional level and via phosphorylation by Akt kinase. Moreover, nuclear localization of hTERT is required to promote elongation of telomere sequences.

Identification of genes regulated by 2-methoxyestradiol (2ME2) in multiple myeloma cells using oligonucleotide arrays.

Our previous study demonstrated that 2-methoxyestradiol (2ME2), an estrogen derivative, induces apoptosis in multiple myeloma (MM) cells; however, the related transcriptional events are unclear. In the present study, we used oligonucleotide microarrays to identify genes altered during 2ME2-induced apoptosis in MM cells. 2ME2 triggers an early transient induction of genes known to trigger cell death and repression of growth/survival-related genes.

Suppression of Fas-FasL-induced endothelial cell apoptosis prevents diabetic blood-retinal barrier breakdown in a model of streptozotocin-induced diabetes.

Diabetic macular edema, resulting from increased microvascular permeability, is the most prevalent cause of vision loss in diabetes. The mechanisms underlying this complication remain poorly understood. In the current study, diabetic vascular permeability (blood-retinal barrier breakdown) is demonstrated to result from a leukocyte-mediated Fas-FasL-dependent apoptosis of the retinal vasculature.

Constitutive nuclear factor-kappaB activity is crucial for human retinoblastoma cell viability.

Retinoblastoma (Rb) is the most common intraocular malignancy of childhood. Although systemic and intrathecal chemotherapy with local and cranial radiotherapy have improved overall survival, the prognosis for patients with central nervous system involvement is still poor. We investigated the role of the transcription factor nuclear factor (NF)-kappaB, which promotes cell survival in several other models, in the pathophysiology of Rb.

CD40 induces human multiple myeloma cell migration via phosphatidylinositol 3-kinase/AKT/NF-kappa B signaling.

Multiple myeloma (MM) is characterized by clonal expansion of malignant plasma cells in the bone marrow and their egress into peripheral blood with progression to plasma cell leukemia. Our previous study defined a functional role of CD40 activation in MM cell homing and migration. In this study, we examine signaling events mediating CD40-induced MM cell migration.

The proteasome inhibitor PS-341 potentiates sensitivity of multiple myeloma cells to conventional chemotherapeutic agents: therapeutic applications.

The proteasome inhibitor PS-341 inhibits nuclear factor-kappaB (NF-kappaB) activation, induces apoptosis in cancer cells, including multiple myeloma (MM) cells, and has marked clinical activity as a monotherapy for MM. In this study, we found that subtoxic concentrations of PS-341 potently sensitized MM cell lines and patient cells to DNA-damaging chemotherapeutic agents such as doxorubicin and melphalan, including cells resistant to these drugs and those isolated from a patient who had relapsed after PS-341 monotherapy. Moreover, PS-341 abolished cell adhesion-mediated drug resistance.

Molecular mechanisms mediating antimyeloma activity of proteasome inhibitor PS-341.

We have recently shown that proteasome inhibitor PS-341 induces apoptosis in drug-resistant multiple myeloma (MM) cells, inhibits binding of MM cells in the bone marrow microenvironment, and inhibits cytokines mediating MM cell growth, survival, drug resistance, and migration in vitro. PS-341 also inhibits human MM cell growth and prolongs survival in a SCID mouse model. Importantly, PS-341 has achieved remarkable clinical responses in patients with refractory relapsed MM.

Molecular sequelae of proteasome inhibition in human multiple myeloma cells.

The proteasome inhibitor PS-341 inhibits IkappaB degradation, prevents NF-kappaB activation, and induces apoptosis in several types of cancer cells, including chemoresistant multiple myeloma (MM) cells. PS-341 has marked clinical activity even in the setting of relapsed refractory MM. However, PS-341-induced apoptotic cascade(s) are not yet fully defined.

Immunomodulatory drug CC-5013 overcomes drug resistance and is well tolerated in patients with relapsed multiple myeloma.

Thalidomide (Thal) can overcome drug resistance in multiple myeloma (MM) but is associated with somnolence, constipation, and neuropathy. In previous in vitro studies, we have shown that the potent immunomodulatory derivative of thalidomide (IMiD) CC-5013 induces apoptosis or growth arrest even in resistant MM cell lines and patient cells, decreases binding of MM cells to bone marrow stromal cells (BMSCs), inhibits the production in the BM milieu of cytokines (interleukin-6 [IL-6], vascular endothelial growth factor [VEGF], tumor necrosis factor-alpha [TNF-alpha]) mediating growth and survival of MM cells, blocks angiogenesis, and stimulates host anti-MM natural killer (NK) cell immunity. Moreover, CC-5013 also inhibits tumor growth, decreases angiogenesis, and prolongs host survival in a human plasmacytoma mouse model.

Proteasome inhibitor PS-341 inhibits human myeloma cell growth in vivo and prolongs survival in a murine model.

The proteasome is a ubiquitous and essential intracellular enzyme that degrades many proteins regulating cell cycle, apoptosis, transcription, cell adhesion,angiogenesis, and antigen presentation. We have shown recently that the proteasome inhibitor PS-341 inhibits growth, induces apoptosis, and overcomes drug resistance in human myeloma cells in vitro. In this study, we examined the efficacy, toxicity, and in vivo mechanism of action of PS-341 using a human plasmacytoma xenograft mouse model.

Activation of NF-kappaB and upregulation of intracellular anti-apoptotic proteins via the IGF-1/Akt signaling in human multiple myeloma cells: therapeutic implications.

Interleukin-6 (IL-6) and insulin-like growth factor-1 (IGF-1) promote the proliferation of multiple myeloma (MM) cells and protect them against dexamethasone (Dex)-induced apoptosis. We have previously shown that Apo2 ligand/TNF-Related apoptosis inducing ligand (Apo2L/TRAIL) induces apoptosis of MM cells, including cells either sensitive or resistant to Dex and cytotoxic drugs, and overcomes the growth and survival effect of IL-6; conversely, NF-kappaB transcriptional activity attenuates their Apo2L/TRAIL-sensitivity. In the current study, we demonstrate that IGF-1 stimulates sustained activation of NF-kappaB and Akt; induces phosphorylation of the FKHRL-1 Forkhead transcription factor; upregulates a series of intracellular anti-apoptotic proteins including FLIP, survivin, cIAP-2, A1/Bfl-1, and XIAP; and decreases Apo2L/TRAIL-sensitivity of MM cells.

Regulation of Apo2L/tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in thyroid carcinoma cells.

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)/Apo2 ligand selectively kills neoplastic cells, including thyroid carcinoma cells (Mitsiades et al: Thyroid carcinoma cells are resistant to FAS-mediated apoptosis but sensitive to tumor necrosis factor-related apoptosis-inducing ligand. Cancer Res 2000, 60:4122-41299). We investigated the mechanisms regulating Apo2L/TRAIL-induced apoptosis in thyroid carcinoma cells, as well as the impact of insulin-like growth factor (IGF)-1, interferon-gamma, and TNF-alpha.

beta-lapachone, a novel plant product, overcomes drug resistance in human multiple myeloma cells.

Objective: To evaluate the anti-tumor potential of beta-lapachone in multiple myeloma (MM) cell lines (U266, RPMI8226, and MM.1S); MM cell lines resistant to dexamethasone (MM.1R), melphalan (RPMI8226/LR5), doxorubicin (RPMI8226/DOX40), and mitoxantrone (RPMI8226/ MR20); and MM cells from patients (MM1-MM4).

Cytokines modulate telomerase activity in a human multiple myeloma cell line.

Telomerase is a ribonucleoprotein DNA polymerase that elongates the telomeres of chromosomes to compensate for losses that occur with each round of DNA replication and maintain chromosomal stability. Interleukin 6 (IL-6) and insulin-like growth factor 1 (IGF-1) are proliferative and survival factors for human multiple myeloma (MM) cells. To date, however, the effects of IGF-1 and IL-6 on telomerase activity and associated sequelae in MM cells have not been characterized.