Biomedical subjects

Gema Mateo

Publications and source records attributed to Gema Mateo.

14 recordsLinked to original sources

PubMed2006

Conventional diagnostics in multiple myeloma.

This paper reviews the most relevant laboratory techniques currently used for the evaluation of patients with multiple myeloma (MM) and other monoclonal gammopathies. Although the bone marrow morphological examination and electrophoretic analysis of the monoclonal paraprotein still remain the 'gold standard' techniques for fast, accurate and cost-effective diagnosis, other assays such as immunophenotyping, DNA cell content and cell cycle analysis measured by flow cytometry may contribute to a better assessment of myeloma patients. Here, we will discuss not only the contribution of each technique to differential diagnosis of monoclonal gammopathies, but also the value of each parameter as prognostic factor and for monitoring treatment efficacy. In addition, possible technical pitfalls inherent to each technique will be analysed.

Biomarkers↗

PubMed2006

The histone deacetylase inhibitor LBH589 is a potent antimyeloma agent that overcomes drug resistance.

Multiple myeloma represents an incurable disease, for which development of new therapies is required. Here, we report the effect on myeloma cells of LBH589, a new hydroxamic acid-derived histone deacetylase inhibitor. LBH589 was a potent antimyeloma agent (IC(50) < 40 nmol/L) on both cell lines and fresh cells from multiple myeloma patients, including cells resistant to conventional chemotherapeutic agents. In addition, LBH589 potentiated the action of drugs, such as bortezomib, dexamethasone, or melphalan. Using gene array, quantitative PCR, and Western analyses, we observed that LBH589 affected a large number of genes involved in cell cycle and cell death pathways. LBH589 blocked cell cycle progression, and this was accompanied by p21, p53, and p57 up-regulation. LBH589 induced cell death through an increase in the mitochondrial outer membrane permeability. LBH589 favored apoptosome formation by inducing cytochrome c release, Apaf-1 up-regulation, and caspase-9 cleavage. In addition, LBH589 stimulated a caspase-independent pathway through the release of AIF from the mitochondria. LBH589 down-regulated Bcl-2 and particularly Bcl-X. Moreover, overexpression of Bcl-X in multiple myeloma cells prevented LBH589-induced cell death. All these data indicate that LBH589 could be a useful drug for the treatment of multiple myeloma patients.

Acetylation↗

PubMed2006

Characterization of bone marrow T cells in monoclonal gammopathy of undetermined significance, multiple myeloma, and plasma cell leukemia demonstrates increased infiltration by cytotoxic/Th1 T cells demonstrating a squed TCR-Vbeta repertoire.

BACKGROUND: The majority of studies published to date regarding the role of the bone marrow (BM) microenvironment in the pathogenesis of monoclonal gammopathies (MG) have focused on the interaction between stroma cells and plasma cells, whereas information concerning the lymphocytes infiltrating the tumor microenvironment is scanty. METHODS: The authors measured the distribution, TCR-Vbeta repertoire, immunophenotype, and functional characteristics of different subsets of BM T lymphocytes from 61 nontreated patients with MG (30 patients with MG of undetermined significance [MGUS], 27 patients with multiple myeloma [MM], and 4 patients with plasma cell leukemia [PCL]). RESULTS: The authors found a significantly increased rate of BM infiltration by T cells in all patient groups, at the expense of CD4+CD8- and CD4-CD8- T lymphocytes and both CD4+CD28- and CD8+CD28- cytotoxic/effector T cell subsets, and associated with TCR-Vbeta expansions in both CD4+ and CD8+ BM T cells in the majority of patients with MGUS, MM, and PCL. Moreover, the percentage of T cells secreting interferon (IFN)-gamma was found to be increased (P < or = 0.05) both in CD4+ and CD8+ T cells in MGUS and MM patients, and a higher plasma concentration of IFN-gamma was found in patients with MM. It is interesting to note that a positive correlation was noted between the proportion of CD28- and both the percentage of IFN-gamma-secreting cells and the proportion of expanded TCR-Vbeta lymphocytes within the total BM CD4+ T cells. CONCLUSIONS: The results of the current study demonstrated an increased infiltration of BM by T cells associated with frequent TCR-Vbeta expansions and a more prominent cytotoxic/Th1 phenotype in all the patient groups studied.

Aged↗

PubMed2005

Genetic abnormalities and patterns of antigenic expression in multiple myeloma.

Myelomatous plasma cells show a high heterogeneity both in their immunophenotypic characteristics as well as in their cytogenetic features. Thus far, no extensive studies have been carried out to explore whether such antigenic diversity is associated with specific genetic characteristics. We have investigated the relationship between the immunophenotypic profile at plasma cell and both their DNA ploidy status (evaluated by flow cytometry) and specific genetic features (ascertained by fluorescence in situ hybridization) in a large series of 915 patients with newly diagnosed multiple myeloma. The non-hyperdiploid multiple myeloma group (n = 454, 52%) was associated with a significantly higher frequency of positivity for CD28 and CD20 as well as a higher incidence of CD56(-) and CD117(-) cases (P < 0.001). Remarkably, 13q deletion and immunoglobulin heavy chain (IGH) gene rearrangements, which were significantly more common in non-hyperdiploid multiple myeloma, showed a strong association with CD117(-) cases. IGH translocation to 11q13 was associated with reactivity for CD20 (P < 0.001), down-regulation of CD56 (P < 0.001), and lack of expression of CD117 (P = 0.001). By contrast, IGH translocations to other chromosome partners were almost exclusively found among CD20(-) and CD117(-) cases (P < 0.001). These results suggest that genetic categories in multiple myeloma exhibit particular immunophenotypic profiles which in turn are strongly associated with the DNA ploidy status.

Adult↗

PubMed2005

Bortezomib is an efficient agent in plasma cell leukemias.

Plasma cell leukemia (PCL) represents the most aggressive form of monoclonal gammopathy for which new treatment approaches are needed. Here we report the effect of Bortezomib on cells from 4 patients with PCL, as well as the in vivo efficacy on a patient with secondary PCL. Bortezomib reduced PCL numbers and was more efficient in cell growth inhibition than dexamethasone or doxorubicin. Treatment with Bortezomib induced procaspase-3 and poly(ADP-ribose) polymerase cleavage and decreased the amount of extracellular signal regulated kinase (Erk1/2) and phospho-Erk1/2. However, Bortezomib did not substantially affect the levels of the Erk1/2 upstream activating kinase (MEK1), p27 or p21. Finally, we had the opportunity to use Bortezomib in a heavily pretreated patient with overt secondary PCL and severe anemia and thrombocytopenia. Following Bortezomib treatment, circulating plasma cells disappeared; what is more striking, the peripheral blood counts returned to normal, becoming transfusion-independent. These data support the inclusion of Bortezomib in the therapeutic armamentarium of PCL.

Anemia↗

PubMed2005

Multifunctional role of Erk5 in multiple myeloma.

Multiple myeloma is characterized by the accumulation of terminally differentiated B cells in the bone marrow, due to increased proliferation and restricted apoptosis of the myelomatous clone. Here we have studied the participation of a novel mitogen-activated protein kinase (MAPK) route, the extracellular signal-regulated kinase 5 (Erk5) pathway, in the regulation of myeloma cell proliferation and apoptosis. Erk5 was expressed in cells isolated from patients and in myeloma cell lines. The myeloma growth factor interleukin 6 (IL-6) activated Erk5, and this activation was independent of Ras and Src. Expression of a dominant-negative form of Erk5 restricted the proliferation of myeloma cells and inhibited IL-6-dependent cell duplication. This dominant-negative form also sensitized myeloma cells to the proapoptotic action of dexamethasone and PS341. The latter compound caused a profound decrease in the amount of endogenous Erk5 and was less effective in inducing apoptosis when the level of Erk5 was increased by transfection of Erk5. These results place the Erk5 route as a new regulatory signaling pathway that affects multiple myeloma proliferation and apoptosis.

Antineoplastic Agents↗

PubMed2005

Immunophenotypic and cytogenetic comparison of Waldenstrom's macroglobulinemia with splenic marginal zone lymphoma.

Some B-cell lymphoproliferative disorders displaying a serum monoclonal immunoglobulin (Ig) M protein could be difficult to differentiate from Waldenstrom's macroglobulinemia (WM). We report on the immunophenotypic and cytogenetic characteristics of 85 patients with WM and compare them with 29 patients with splenic marginal zone lymphoma (SMZL). For immunophenotyping, WM and SMZL constantly expressed panB-cell markers (CD19, CD20, CD22, and surface Ig). However, there were differences in the k/l ratio (1.2:1 for SMZL and 4.5:1 for WM) and in some markers such as CD22 and CD11c, which were overexpressed in patients with SMZL compared with patients with WM, whereas CD25 was more frequently positive in WM (88% vs. 44%). The CD103 antigen was always negative in WM, whereas it was positive in 40% of SMZL cases. The monoclonal antibody FMC7 was usually positive in both entities: heterogeneous in WM but homogeneous in SMZL. The combination of CD25 and CD22 could differentiate between WM and SMZL. The principal molecular abnormality in WM is 6q deletion (30% in our experience), whereas in SMZL the most common abnormalities are loss of 7q (19%) along with +3q (19%) and +5q (10%). Interestingly, the incidence of IgH rearrangement was low in WM (12%) and SMZL (10%). Immunophenotypic and molecular cytogenetic studies could help to distinguish WM from SMZL.

Antigens, CD↗

PubMed2005

Cell cycle analysis of Waldenstrom's macroglobulinemia.

Little is known about the DNA cell content and cell cycle characteristics of immunoglobulin (Ig) M monoclonal gammopathies. The autonomous clone appears to be rather heterogeneous, from mature B lymphocytes to plasma cells (PCs). We have evaluated the DNA cell content of 27 patients with IgM monoclonal gammopathies: 18 of them had Waldenstrom's macroglobulinemia (WM), and 9 were diagnosed with IgM-monoclonal gammopathy of undetermined significance (MGUS). To specifically analyze the cell cycle of the B lymphocyte and PC populations, we used a flow-cytometric double-staining technique with CD19/CD20/CD22 propidium iodide for B lymphocytes and CD38/CD138 propidium iodide for PCs. In 26 of 27 patients, both subsets of tumor cells (B lymphocyte and PC) showed a diploid DNA cell content (DNA index, 1). The median percentage of proliferating B lymphocytes, S-phase + G2/M-phase, was 1.8% (range, 0.4%-4.1%). This proliferative activity was significantly lower than that observed in nonmalignant cells (5.7%; range, 0.1%-14.2%; P = 0.004) in the same sample. No differences were observed when comparing the proliferative activity of WM with that of IgM MGUS (median, 1.7% vs. 2.2%, respectively). Cell cycle characteristics of PCs were simultaneously evaluated in 9 patients, with 1.8% cells in S phase or G2/M phase. In summary, the cell cycle analysis showed that IgM monoclonal gammopathies are low-proliferative disorders, with a DNA ploidy pattern (diploid) clearly different from that of multiple myeloma.

Cell Cycle↗

PubMed2005

Minimal residual disease monitoring in multiple myeloma: a comparison between allelic-specific oligonucleotide real-time quantitative polymerase chain reaction and flow cytometry.

BACKGROUND AND OBJECTIVES: Minimal residual disease (MRD) studies are useful in multiple myeloma (MM). However, the definition of the best technique and clinical utility are still unresolved issues. The aim of this study was to analyze and compare the clinical utility of MRD studies in MM with two different techniques: allelic-specific oligonucleotide real-time quantitative PCR (ASO-RQ-PCR), and flow cytometry (FCM). DESIGN AND METHODS: Bone marrow samples from 32 MM patients who had achieved complete response after transplantation were evaluated by ASO-RQ-PCR, using TaqMan technology, and multiparametric FCM. RESULTS: ASO-RQ-PCR was only applicable in 75% of patients for a variety of technical reasons, while FCM was applicable in up to 90%. Therefore, simultaneous PCR/FCM analysis was possible in only 24 patients. The number of residual tumor cells identified by both techniques was very similar (mean=0.29%, range=0.001-1.61%, correlation coefficient=0.861). However, RQ-PCR was able to detect residual myelomatous cells in 17 patients while FCM only did so in 11; thus, 6 cases were FCM negative but PCR positive, all of them displaying a very low number of clonal cells (median=0.014%, range=0.001-0.11). Using an MRD threshold of 0.01% (10(-4)) two risk groups with significantly different progression-free survival could be identified by either PCR (34 vs. 15m, p=0.04) or FCM (27 vs. 10m, p=0.05). INTERPRETATION AND CONCLUSIONS: Although MRD evaluation by ASO-RQ-PCR is slightly more sensitive and specific than FCM, it is applicable in a lower proportion of MM patients and is more time-consuming, while both techniques provide similar prognostic information.

Aged↗

PubMed2004

Prognostic and biologic significance of chromosomal imbalances assessed by comparative genomic hybridization in multiple myeloma.

Cytogenetic abnormalities, evaluated either by karyotype or by fluorescence in situ hybridization (FISH), are considered the most important prognostic factor in multiple myeloma (MM). However, there is no information about the prognostic impact of genomic changes detected by comparative genomic hybridization (CGH). We have analyzed the frequency and prognostic impact of genetic changes as detected by CGH and evaluated the relationship between these chromosomal imbalances and IGH translocation, analyzed by FISH, in 74 patients with newly diagnosed MM. Genomic changes were identified in 51 (69%) of the 74 MM patients. The most recurrent abnormalities among the cases with genomic changes were gains on chromosome regions 1q (45%), 5q (24%), 9q (24%), 11q (22%), 15q (22%), 3q (16%), and 7q (14%), while losses mainly involved chromosomes 13 (39%), 16q (18%), 6q (10%), and 8p (10%). Remarkably, the 6 patients with gains on 11q had IGH translocations. Multivariate analysis selected chromosomal losses, 11q gains, age, and type of treatment (conventional chemotherapy vs autologous transplantation) as independent parameters for predicting survival. Genomic losses retained the prognostic value irrespective of treatment approach. According to these results, losses of chromosomal material evaluated by CGH represent a powerful prognostic factor in MM patients.

Aged↗

PubMed2003

Imatinib mesylate (STI571) inhibits multiple myeloma cell proliferation and potentiates the effect of common antimyeloma agents.

c-Kit has been shown to be mutated in several types of tumours, and its activity has been correlated with increased proliferation rates in a subset of multiple myeloma (MM) patients. We have investigated the effect of imatinib mesylate (STI571), an inhibitor of c-Kit, on MM cells. STI571 inhibited the proliferation of MM cells by arresting cell cycle progression. Western blotting of cell cycle proteins showed that STI571 increased the levels of p21 and p16. MM cells expressed abl, but its level of tyrosine phosphorylation was low and unaffected by treatment with STI571. c-Kit was also expressed in certain MM cell lines, and its phosphorylation was stimulated by stem cell factor. However, the failure to detect the receptor protein in other MM cell lines in which cell proliferation was inhibited by STI571 suggests that its effect on these c-Kit-negative MM cell lines might be caused by the action of the drug on yet unknown targets. STI571 inhibited the proliferation of MM cells resistant to dexamethasone or melphalan and had an additive effect when combined with dexamethasone. Efforts to understand the action of STI571 in MM cells may help to identify these potentially useful targets in the treatment of this and other disorders.

Antineoplastic Agents↗

PubMed2003

Immunophenotypic analysis of peripheral blood stem cell harvests from patients with multiple myeloma.

BACKGROUND AND OBJECTIVES: Four-color multiparameter immunophenotyping has recently proven to be an attractive technique for evaluating the plasma cell (PC) compartment since it allows discrimination between myelomatous and normal PC. This study was designed to investigate: i) whether peripheral blood is less contaminated than bone marrow as a source for an autologous transplant; ii) the effect of growth factors on mobilizing myelomatous PC into peripheral blood; iii) the degree of contamination by myelomatous PC in apheresis samples; and iv) whether the number of PC increases during the last days of apheresis. DESIGN AND METHODS: Using 4-color antigen staining we investigated the composition of the PC compartment in 90 apheresis products from 40 patients with MM; in 17 cases bone marrow and peripheral blood samples were also simultaneously evaluated. RESULTS: (i) All pre-mobilization bone marrow samples analyzed were always contaminated with myelomatous PC whereas only 41% of the post-mobilization peripheral blood samples were contaminated. Moreover, the use of peripheral blood would lead to a reduction of >5x10(5) infused myelomatous PC; (ii) mobilization with cytokines increased the number of circulating PC, generally because of an expansion of the normal PC population; (iii) forty-eight percent of all peripheral blood stem cell harvests were contaminated with myelomatous PC, although normal PC usually represented the predominant population; (iv) no significant changes were observed in the amount of contaminating myelomatous PC during the first three days of apheresis. INTERPRETATION AND CONCLUSIONS: Multiparameter immunophenotyping is a useful approach for investigating the PC compartment in apheresis products.

Adult↗

PubMed2002

Immunophenotypic evaluation of the plasma cell compartment in multiple myeloma: a tool for comparing the efficacy of different treatment strategies and predicting outcome.

Multiparametric immunophenotyping can be a sensitive method for analyzing the plasma cell (PC) compartment in patients with multiple myeloma because it discriminates between myelomatous and normal PCs. Using this approach, we compared the efficacy of high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) with that of conventional chemotherapy. We found that ASCT provided a significantly greater reduction in the level of residual tumor PCs and with better recovery of normal PCs. This profile of coexistence of normal PCs and myelomatous PCs resembled that observed in monoclonal gammopathy of undetermined significance. We also found that treatment-induced changes in the PC compartment correlated with disease outcome. Thus, patients in whom at least 30% of gated PCs had a normal phenotype after treatment had a significantly longer progression-free survival (60 +/- 6 months versus 34 +/- 12 months; P =.02).

Adult↗

PubMed2002

Pamidronate induces bone formation in patients with smouldering or indolent myeloma, with no significant anti-tumour effect.

Twelve patients with smouldering or indolent multiple myeloma (MM) received 12 courses of intravenous pamidronate as a single agent to evaluate both the antitumour and bone metabolism effects. One patient achieved minor response, eight had stable disease, and three - all indolent MM - showed disease progression. Serum interleukin 6 (IL-6), IL-1beta and Oncostatin-M remained stable throughout the study, while tumour necrosis factor-alpha increased. Bone density significantly increased after four and 12 courses compared with baseline. Markers for bone resorption and bone formation decreased with treatment. These results suggest that pamidronate treatment reduces bone turnover in smouldering or indolent MM, but has no significant antitumour effect.

Aged↗