Impact of CD138 Magnetic Bead-based Positive Selection on Bone Marrow Plasma Cell Surface Markers.

Background: Isolation of malignant plasma cells from bone marrow of patients with monoclonal gammopathies is critical for studies into the disease biology. The plasma cells are typically isolated by positive selection using plasma cell markers such as CD138. Here we have examined the effect of CD138 magnetic bead selection on the expression of other surface phenotypic markers on plasma cells.

Histone deacetylase inhibition in combination with MEK or BCL-2 inhibition in multiple myeloma.

Despite recent advances in the treatment of multiple myeloma, patients with this disease still inevitably relapse and become refractory to existing therapies. Mutations in , and are common in multiple myeloma, affecting 50% of patients at diagnosis and >70% at relapse. However, targeting mutated via MEK inhibition is merely cytostatic in myeloma and largely ineffective in the clinic.

Aurora kinase and FGFR3 inhibition results in significant apoptosis in molecular subgroups of multiple myeloma.

Aberrant expression of proteins involved in cell division is a constant feature in multiple myeloma (MM), especially in high-risk disease. Increasingly, therapy of myeloma is moving towards individualization based on underlying genetic abnormalities. Aurora kinases are important mediators of cell cycle and are up regulated in MM.

Smac mimetic LCL161 overcomes protective ER stress induced by obatoclax, synergistically causing cell death in multiple myeloma.

Bcl2 and IAP families are anti-apoptotic proteins deregulated in multiple myeloma (MM) cells. Pharmacological inhibition of each of these families has shown significant activity only in subgroups of MM patients. Here, we have examined a broad-spectrum Bcl2 family inhibitor Obatoclax (OBX) in combination with a Smac mimetic LCL161 in MM cell lines and patient cells.

Multiple mechanisms contribute to the synergistic anti-myeloma activity of the pan-histone deacetylase inhibitor LBH589 and the rapalog RAD001.

We examined the pre-clinical activity of pan-histone deacetylase inhibitor LBH589 in combination with mTORC1 inhibitor RAD001 and observed that the drug combination strongly synergized in inducing cytotoxicity in multiple myeloma (MM) cells. LBH589 caused an increase in acetylated histones and RAD001 inhibited mTORC1 activity. RAD001 caused potent G0/G1 arrest while LBH589 induced pronounced apoptosis, both of which were enhanced when the drugs were used in combination.

Phase II study of bevacizumab in combination with sorafenib in recurrent glioblastoma (N0776): a north central cancer treatment group trial.

Purpose: We hypothesized that vertical blockade of VEGF signaling by combining bevacizumab with sorafenib in patients with recurrent glioblastoma would result in a synergistic therapeutic effect. We also investigated whether VEGF, VEGFR2 and hypoxia-inducible factor-1α single-nucleotide polymorphisms (SNP), circulating biomarkers of angiogenesis, and MRI markers such as apparent diffusion coefficient (ADC) are correlated with treatment efficacy and/or toxicity.

Experimental Design: Patients received bevacizumab (5 mg/kg every 2 weeks) with sorafenib (200 mg twice a day, weekly, days 1-5; group A).

Anti-myeloma activity of Akt inhibition is linked to the activation status of PI3K/Akt and MEK/ERK pathway.

The PI3K/Akt/mTOR signal transduction pathway plays a central role in multiple myeloma (MM) disease progression and development of therapeutic resistance. mTORC1 inhibitors have shown limited efficacy in the clinic, largely attributed to the reactivation of Akt due to rapamycin induced mTORC2 activity. Here, we present promising anti-myeloma activity of MK-2206, a novel allosteric pan-Akt inhibitor, in MM cell lines and patient cells.

Sorafenib, a multikinase inhibitor, is effective in vitro against non-Hodgkin lymphoma and synergizes with the mTOR inhibitor rapamycin.

Non-Hodgkin lymphoma (NHL) represents a heterogenous group of neoplasias originating from lymphoid cells. Increased angiogenesis and expression of Vascular Endothelial Growth Factor (VEGF) and its receptors (VEGFR) have been found to be associated with NHL disease progression. Increase in VEGF and other cytokines stimulate signaling cascades, including the Ras/Raf/Mek/Erk pathway, resulting in increased proliferation and decreased apoptosis.

Immunophenotyping in multiple myeloma and related plasma cell disorders.

Plasma cell disorders form a spectrum ranging from the asymptomatic presence of small monoclonal populations of plasma cells to conditions like plasma cell leukemia and multiple myeloma, in which the bone marrow can be replaced by the accumulation of neoplastic plasma cells. Immunophenotyping has become an invaluable tool in the management of hematological malignancies and is increasingly finding a role in the diagnosis and monitoring of plasma cell disorders. Multiparameter flow cytometry has evolved considerably during the past decade with an increasing ability to screen large numbers of events and to detect multiple antigens at the same time.

TG101209, a novel JAK2 inhibitor, has significant in vitro activity in multiple myeloma and displays preferential cytotoxicity for CD45+ myeloma cells.

Interaction of myeloma cells with the bone marrow microenvironment is mediated in large part through different cytokines, especially VEGF and IL6. These cytokines, especially IL6, leads to upregulation of the JAK/STAT pathway in myeloma cell, contributing to increased proliferation, decreased apoptosis, and acquired drug resistance. Here, we examined the preclinical activity of a novel JAK2 inhibitor TG101209.

R-(-)-gossypol (AT-101) activates programmed cell death in multiple myeloma cells.

Objective: Bcl-2 family proteins play a critical role in malignancies by regulating the balance between cell survival and apoptosis. R-(-)-gossypol (AT-101) is a small molecule that mimics the BH3 domain of cellular Bcl-2 inhibitors and interferes with the function of prosurvival Bcl-2 proteins. We examined the cytotoxicity of AT-101 in the context of multiple myeloma, a fatal hematological malignancy.

Mechanisms of regulation of CXCR4/SDF-1 (CXCL12)-dependent migration and homing in multiple myeloma.

The mechanisms by which multiple myeloma (MM) cells migrate and home to the bone marrow are not well understood. In this study, we sought to determine the effect of the chemokine SDF-1 (CXCL12) and its receptor CXCR4 on the migration and homing of MM cells. We demonstrated that CXCR4 is differentially expressed at high levels in the peripheral blood and is down-regulated in the bone marrow in response to high levels of SDF-1.

A phase II trial of imatinib in patients with refractory/relapsed myeloma.

Although imatinib was designed to specifically inhibit the bcr-abl gene product, it inhibits other receptor tyrosine kinases including c-kit. As pre-clinical data, 126 patients with plasma cell disorders and 19 controls were evaluated for c-kit expression. Patients were eligible for the treatment trial if they had relapsed/refractory myeloma.

FISH is superior to PCR in detecting t(14;18)(q32;q21)-IgH/bcl-2 in follicular lymphoma using paraffin-embedded tissue samples.

Detection of t(14;18)(q32;q21)-IgH/bcl-2, which is present in 70% to 95% of follicular lymphomas (FLs), might aid in diagnosing FL. The efficacy of routine polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) techniques in detecting t(14;18) in paraffin-embedded tissue samples was compared on 5 normal tonsils and 28 FLs demonstrated to be t(14;18)+ by previous karyotyping. There was technical failure in 14 (50%) of the FLs by PCR, likely due to B-5 fixation, and 4 (14%) of FLs by FISH, likely due to advanced specimen age.

Bone marrow angiogenic ability and expression of angiogenic cytokines in myeloma: evidence favoring loss of marrow angiogenesis inhibitory activity with disease progression.

We compared the angiogenic potential of bone marrow plasma and the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors on plasma cells from patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and newly diagnosed multiple myeloma (NMM). Cytokine and cytokine-receptor expression was studied by bone marrow immunohistochemistry, quantitative reverse transcription-polymerase chain reaction (RT-PCR) on sorted plasma cells, and quantitative Western blot analysis. Bone marrow angiogenic potential was studied using a human in vitro angiogenesis assay.

Flow cytometric assessment of TCR-Vbeta expression in the evaluation of peripheral blood involvement by T-cell lymphoproliferative disorders: a comparison with conventional T-cell immunophenotyping and molecular genetic techniques.

Molecular genetic T-cell receptor (TCR) and flow cytometric analysis using antibodies to conventional T-cell antigens and TCR beta-chain variable region families (TCR-Vbeta) were performed in 65 peripheral blood specimens evaluated for potential involvement by a T-cell lymphoproliferative disorder (TCLPD). A normal or reactive conventional T-cell immunophenotype was present in 36 cases; TCR-Vbeta flow cytometric and molecular TCR analyses were negative for clonality in 32 and 27 of these cases, respectively. In the remaining normal and reactive cases, one or both methods seemed to detect dominant cell populations in settings with limited T-cell diversity.

Flt-3 and c-kit mutation studies in a spectrum of chronic myeloid disorders including systemic mast cell disease.

We screened 115 patients with chronic myeloid disorders (CMD) for known flt-3 and c-kit mutations in both the juxtamembrane (JM) and the activation loop (AL) domains. None of the patients displayed flt-3 (JM or AL) or c-kit JM mutations. However, the c-kit AL (D816V) mutation was detected in 5 of 16 patients with systemic mast cell disease (SMCD) but in none of the remaining 99 patients with other CMD.

Expression of CD52 on plasma cells in plasma cell proliferative disorders.

Multiple myeloma (MM) and primary systemic amyloidosis (AL) remain incurable disorders, and new treatments targeted to the malignant plasma cells are needed. Alemtuzumab is a humanized monoclonal antibody to CD52 and has activity in chronic lymphocytic leukemia. We examined the CD52 expression on CD45+ and CD45- plasma cell populations to evaluate the potential for using alemtuzumab for these disorders.

Differential expression of CD2 on neoplastic mast cells in patients with systemic mast cell disease with and without an associated clonal haematological disorder.

Recently, aberrant coexpression of CD2 and CD25 has been reported to reliably distinguish neoplastic mast cells from normal or so-called reactive mast cells. Such expression is included in the consensus diagnostic criteria for systemic mast cell disease (SMCD). In our study of patients with SMCD, we found CD2 expression to be more prevalent on mast cells from patients without an associated haematological disorder (P = 0.

Detection of circulating cytokeratin-positive cells in the blood of breast cancer patients using immunomagnetic enrichment and digital microscopy.

Purpose: To examine the feasibility for identifying and enumerating cytokeratin positive (CK+) cells in the peripheral blood of breast cancer patients.

Experimental Design: Blood specimens from 34 normal donors (negative controls), 15 samples to which carcinoma cells were added (positive controls), and 84 breast cancer patients [27 node-negative (N-), 29 node-positive (N+), and 28 metastatic] were studied. RBCs were lysed with ammonium chloride and the resulting cell suspension incubated with anti-EpCAM-conjugated immunomagnetic beads for carcinoma cell enrichment.