Multiple myeloma and persistence of drug resistance in the age of novel drugs (Review).

Multiple myeloma (MM) is a mature B cell neoplasm that results in multi-organ failure. The median age of onset, diverse clinical manifestations, heterogeneous survival rate, clonal evolution, intrinsic and acquired drug resistance have impact on the therapeutic management of the disease. Specifically, the emergence of multidrug resistance (MDR) during the course of treatment contributes significantly to treatment failure. The introduction of the immunomodulatory agents and proteasome inhibitors has seen an increase in overall patient survival, however, for the majority of patients, relapse remains inevitable with evidence that these agents, like the conventional chemotherapeutics are also subject to the development of MDR. Clinical management of patients with MM is currently compromised by lack of a suitable procedure to monitor the development of clinical drug resistance in individual patients. The current MM prognostic measures fail to pick the clonotypic tumor cells overexpressing drug efflux pumps, and invasive biopsy is insufficient in detecting sporadic tumors in the skeletal system. This review summarizes the challenges associated with treating the complex disease spectrum of myeloma, with an emphasis on the role of deleterious multidrug resistant clones orchestrating relapse.

Changing Arctic snow cover: A review of recent developments and assessment of future needs for observations, modelling, and impacts.

Snow is a critically important and rapidly changing feature of the Arctic. However, snow-cover and snowpack conditions change through time pose challenges for measuring and prediction of snow. Plausible scenarios of how Arctic snow cover will respond to changing Arctic climate are important for impact assessments and adaptation strategies. Although much progress has been made in understanding and predicting snow-cover changes and their multiple consequences, many uncertainties remain. In this paper, we review advances in snow monitoring and modelling, and the impact of snow changes on ecosystems and society in Arctic regions. Interdisciplinary activities are required to resolve the current limitations on measuring and modelling snow characteristics through the cold season and at different spatial scales to assure human well-being, economic stability, and improve the ability to predict manage and adapt to natural hazards in the Arctic region.

Isolation of Human CD138(+) Microparticles from the Plasma of Patients with Multiple Myeloma.

The confinement of multiple myeloma (MM) to the bone marrow microenvironment requires an invasive bone marrow biopsy to monitor the malignant compartment. The existing clinical tools used to determine treatment response and tumor relapse are limited in sensitivity mainly because they indirectly measure tumor burden inside the bone marrow and fail to capture the patchy, multisite tumor infiltrates associated with MM. Microparticles (MPs) are 0.1- to 1.0-µm membrane vesicles, which contain the cellular content of their originating cell. MPs are functional mediators and convey prothrombotic, promalignant, proresistance, and proinflammatory messages, establishing intercellular cross talk and bypassing the need for direct cell-cell contact in many pathologies. In this study, we analyzed plasma cell-derived MPs (CD138(+)) from deidentified MM patients (n = 64) and normal subjects (n = 18) using flow cytometry. The morphology and size of the MPs were further analyzed using scanning electron microscopy. Our study shows the proof of a systemic signature of MPs in MM patients. We observed that the levels of MPs were significantly elevated in MM corresponding to the tumor burden. We provide the first evidence for the presence of MPs in the peripheral blood of MM patients with potential applications in personalized MM clinical monitoring.

Thalidomide consolidation improves progression-free survival in myeloma with normal but not up-regulated expression of fibroblast growth factor receptor 3: analysis from the Australasian Leukaemia and Lymphoma Group MM6 clinical trial.

The translocation t(4;14) is associated with a poor prognosis in myeloma, but its effect in the setting of new drugs such as thalidomide, bortezomib and lenalidomide continues to be investigated, and the role of candidate genes such as FGFR3 (fibroblast growth factor receptor 3) is not yet clarified. In the Australasian Leukaemia and Lymphoma Group (ALLG) MM6 randomized study comparing consolidation thalidomide and prednisolone with prednisolone alone following autologous stem cell transplant, patients on consolidation thalidomide and prednisolone had superior progression-free (PFS) and overall survival (OS). We now show that thalidomide consolidation benefited both t(4;14)-positive (PFS 29 vs. 17 months, p =0.03) and -negative (52 vs. 24 months, p =0.04) disease. PFS for patients with normal FGFR3 expression was significantly better than for those with up-regulated FGFR3 (31 vs. 21 months, p =0.02). Consolidation thalidomide conferred an improved PFS in patients with normal FGFR3 expression (41 vs. 19 months, p =0.02), but there was no improvement in patients with up-regulated FGFR3 (31 vs. 29 months, p =0.76). We conclude that consolidation thalidomide may mitigate the poor prognostic effect of t(4;14), and improves PFS in normal but not up-regulated FGFR3 expression. Thus the level of FGFR3 expression provides additional prognostic information to t(4;14) in myeloma induction and consolidation therapy.

Factors influencing the abundance of the side population in a human myeloma cell line.

Side population (SP) refers to a group of cells, which is capable to efflux Hoechst 33342, a DNA-binding dye. SP cells exist both in normal and tumor tissues. Although SP abundance has been used as an indicator for disease prognostic and drug screening in many research projects, few studies have systematically examined the factors influencing SP analysis. In this study we aim to develop a more thorough understanding of the multiple factors involved in SP analysis including Hoechst 33342 staining and cell culture. RPMI-8226, a high SP percentage (SP%) human myeloma cell line was employed here. The results showed that SP% was subject to staining conditions including: viable cell proportion, dye concentration, staining cell density, incubation duration, staining volume, and mix interval. In addition, SP% was highest in day one after passage, while dropped steadily over time. This study shows that both staining conditions and culture duration can significantly affect SP%. In this case, any conclusions based on SP% should be interpreted cautiously. The relation between culture duration and SP% suggests that the incidence of SP cells may be related to cell proliferation and cell cycle phase. Maintaining these technical variables consistently is essential in SP research.

The impact of mandatory fortification of flour with folic acid on the blood folate levels of an Australian population.

OBJECTIVE: To determine the impact that mandatory fortification with folic acid of wheat flour used in breadmaking has had on the blood folate levels of an Australian population since it was introduced in September 2009. DESIGN, SETTING AND PATIENTS: A retrospective analysis of serum and red blood cell (RBC) folate levels of 20,592 blood samples collected between April 2007 and April 2010 from a wide variety of inpatients and outpatients and analysed in a large public hospital diagnostic pathology laboratory. MAIN OUTCOME MEASURES: Prevalences of low levels of serum and RBC folate and monthly mean levels before and after introduction of mandatory fortification. RESULTS: Between April 2009 and April 2010, there was a 77% reduction in the prevalence of low serum folate levels (from 9.3% to 2.1%) in all samples tested and an 85% reduction in the prevalence of low RBC folate levels (from 3.4% to 0.5%). In April 2010, the prevalence of low RBC folate levels for females of childbearing age was 0.16% for all samples. There was a 31% increase in mean serum folate level (from 17.7 nmol/L to 23.1 nmol/L; t = 9.3, P < 0.01), and a 22% increase in mean RBC folate level (from 881 nmol/L to 1071 nmol/L). The greatest increment in mean serum folate levels occurred in September 2009, the month that mandatory fortification was introduced, although there was evidence of a gradual change during the preceding months. CONCLUSION: The introduction of mandatory fortification with folic acid has significantly reduced the prevalence of folate deficiency in Australia, including in women of childbearing age.

Clonal expansions of cytotoxic T cells exist in the blood of patients with Waldenstrom macroglobulinemia but exhibit anergic properties and are eliminated by nucleoside analogue therapy.

T cells contribute to host-tumor interactions in patients with monoclonal gammopathies. Expansions of CD8(+)CD57(+) T-cell receptor Vbeta-positive (TCRVbeta(+))-restricted cytotoxic T-cell (CTL) clones are found in 48% of patients with multiple myeloma and confer a favorable prognosis. We now report that CTL clones with varying TCRVbeta repertoire are present in 70% of patients with Waldenström macroglobulinemia (WM; n = 20). Previous nucleoside analog (NA) therapy, associated with increased incidence of transformation to aggressive lymphoma, significantly influenced the presence of TCRVbeta expansions (chi(2) = 11.6; P < .001), as 83% of patients without (n = 6) and only 7% with (n = 14) TCRVbeta expansions had received NA. Clonality of CD3(+)CD8(+)CD57(+)TCRVbeta(+)-restricted CTLs was confirmed by TCRVbeta CDR3 size analysis and direct sequencing. The differential expression of CD3(+)CD8(+)CD57(+)TCRVbeta(+) cells was profiled using DNA microarrays and validated at mRNA and protein level. By gene set enrichment analysis, CTL clones expressed not only genes from cytotoxic pathways (GZMB, PRF1, FGFBP2) but also genes that suppress apoptosis, inhibit proliferation, arrest cell-cycle G1/S transition, and activate T cells (RAS, CSK, and TOB pathways). Proliferation tracking after stimulation confirmed their anergic state. Our studies demonstrate the incidence, NA sensitivity, and nature of clonal CTLs in WM and highlight mechanisms that cause anergy in these cells.

Prognostically significant cytotoxic T cell clones are stimulated after thalidomide therapy in patients with multiple myeloma.

The expanded T cell clones are associated with a prolonged survival in patients with multiple myeloma. We sought to confirm this prognostic significance in a multicenter patient cohort and investigate the effect of thalidomide on clones and T regulatory cells (T(regs)). Blood was collected from 120 patients enrolled in a Phase III trial of maintenance therapy +/- thalidomide after autologous stem cell transplantation. TCR Vbeta repertoire analysis identified T cell expansions in 48% of patients pre-transplant and 68% after 8-month maintenance. T cell expansions, previously shown to be clonal, were predominantly CD8+ (93%) and all 24 TCR Vbeta families tested were represented. Thalidomide therapy was associated with a significant increase in the incidence of patients with multiple expansions (49% vs. 23%; chi2 = 6.8; p = 0.01). The presence of expansions regardless of therapy was associated with a significantly longer median progression free survival (PFS) (32.1 vs. 17.6 months; chi2 = 5.6; p = 0.02) and overall survival (OS) (chi2 = 3.9; p < 0.05). Median PFS in the thalidomide arm was 50.9 months for patients with expansions and 28.3 months for patients without expansions (chi2 = 19.4; p = 0.0002). Thalidomide did not appear to modulate T(reg) numbers. Expanded T cell clones are prognostically significant and have an impact on progression after thalidomide therapy in a proportion of patients.

Regulatory T cells and multiple myeloma.

Many clinical observations point to active immunologic phenomena in patients with myeloma. These consist of active suppression of the host's immune system and partially successful attempts by the host's immune system to suppress the malignant B-cell population. Clinical conditions such as asymptomatic myeloma, which represents clinical presentation in the plateau phase of the disease, plateau establishment after conventional induction therapy without the ongoing need for therapy, and the positive prognostic importance of the presence of clones of cytotoxic T cells in the peripheral blood of some patients, suggest that host-tumor interaction is an active dynamic state. Regulatory T (Treg) cells comprise 5%-10% of peripheral CD4 T cells and are responsible for the control of autoimmune phenomena. Deficiency of the FoxP3 transcription factor, which normally characterizes Treg cells, leads to multiorgan autoimmune disorders in humans and mice. The role of Treg cells in the protection from malignancy is unclear, but their depletion can lead to the induction of tumor rejection in murine models, and their demonstration as tumorinfiltrating lymphocytes in malignancy point to a significant immunomodulator role. In myeloma, host-tumor immune interactions are complex. However, patients can clearly exhibit control of their B-cell malignancy for many years with stability of paraprotein levels, demonstrating a homeostasis between tumor and host. Whether Treg cells are playing a role in this homeostasis is unclear. At present, there is considerable debate in the literature regarding observations such as whether Treg cells are increased or decreased, functional or dysfunctional. In this review, we will discuss the potential importance of Treg cells and their role in myeloma, a disease characterized by a unique set of host-tumor interactions.

Southern blotting of IgH rearrangements in B-cell disorders.

Southern blotting is a method whereby DNA fragments in the gel are denatured by soaking in an alkali solution, carried out of the gel, and transferred onto a membrane. After drying the membrane, the DNA is fixed irreversibly. The net result is a replica on the membrane of the DNA fragment pattern from the agarose gel. This technique is used to demonstrate B-cell clonality in blood and bone marrow down to the 1% level, though more reliably at the 5% level. The analysis is relatively nonselective and will detect novel rearrangements in relapse that were not seen at diagnosis. Modifications of the technique have been used to determine illegitimate switch recombinations and mutations of oncogenes.

Identification of malignant plasma cells by mRNA in situ hybridization.

Patients with multiple myeloma have a clonal proliferation of malignant plasma cells, each with an identical rearrangement of immunoglobulin heavy and light chain genes. When these unique sequences are determined, a valuable molecular tool is available that can been used to detect the presence of the malignant population. Previous methods have employed oligonucleotides derived from these sequences and allele-specific polymerase chain reaction to detect clonality. The method described in this chapter uses mRNA in situ hybridization (ISH) to demonstrate the presence of individual malignant cells. Single-cell analysis using mRNA ISH provides opportunities that when combined with immunophenotyping offer a valuable new investigative tool.

Clonal cytotoxic T cells in myeloma.

Multiple myeloma (MM) is a malignant disease characterized by accumulation of morphologically recognizable plasma cells producing immunoglobulin (Ig) in the bone marrow. The occurrence of clonal T cells in MM, as defined by the presence of rearrangements in the T-cell receptor (TCR)-beta chains detected on Southern blotting, is associated with an improved prognosis. This review aims to describe the various ways in which we have demonstrated the presence of such T cell clones, and to describe the phenotype of these cells. Finally, the specificities of these clinically important CD8+ T cell populations will be discussed in the context of immunotherapy.

Prediction of high affinity class I-restricted multiple myeloma idiotype peptide epitopes.

Idiotypic determinants are potential patient-specific tumor antigens in multiple myeloma (MM). In this study, we have determined the DNA sequence of the variable region of the tumor immunoglobulin (Ig) in 6 patients with MM. We then selected high affinity class I-restricted T-cell peptide epitopes in tumor Ig using two different internet-based epitope prediction programs. High affinity binding peptides were identified by at least one program in 4 out of 6 patients. Of these 35 peptides, only 3 scored high by both analyses. Given that all 6 patients had expanded T-cell clones with a cytotoxic (CD57+CD8+CD28-perforin+) phenotype, known to be associated with a longer survival and postulated to recognise tumor epitopes, this analysis indicates that such clones are unlikely to be exclusively directed towards tumor immuoglobulin, and suggests the need to expand the scope of the search for tumor epitopes with the ability to stimulate cytotoxic T cells in vivo.