ALBERT

Description: Rho GTPases control many facets of cell polarity and migration; namely, the reorganization of the cellular cytoskeleton to extracellular stimuli. Rho GTPases are activated by GTP exchange factors (GEFs), which induce guanosine diphosphate (GDP) release and the stabilization of the nucleotide-free state. Thus, the role of GEFs in the regulation of the cellular response to extracellular cues during cell migration is a critical step of this process. In this report, we have analyzed the activation and subcellular localization of the hematopoietic GEF Vav in human peripheral blood lymphocytes stimulated with the chemokine stromal cell–derived factor-1 (SDF-1α). We show a robust activation of Vav and its redistribution to motility-associated subcellular structures, and we provide biochemical evidence of the recruitment of Vav to the membrane of SDF-1α–activated human lymphocytes, where it transiently interacts with the SDF-1α receptor CXCR4. Overexpression of a dominant negative form of Vav abolished lymphocyte polarization, actin polymerization, and migration. SDF-1α–mediated cell polarization and migration also were impaired by overexpression of an active, oncogenic Vav, although the mechanism appears to be different. Together, our data postulate a pivotal role for Vav in the transmission of the migratory signal through the chemokine receptor CXCR4.

Description: Mesenchymal stem cells (MSC) are multilineage non hematopoietic progenitor cells that play a key role in supporting the lymphohematopoietic system. Their distribution in bone marrow and secondary lymphoid organs allows an intimate interaction with T and B-lymphocytes, which contribute to the normal lymph node development, but this interaction, can not be considered as a simple bi-directional cross-talk and other cell subsets, such as dendritic cells (DC), must be considered. We have analysed the effect of MSC on B-lymphocytes and the pathways involved in these effects. For these propose, we cultured B-cell with or without MSC and analysed different markers involved in the differentiation of B-cells. We found that MSC inhibited proliferation, arresting B lymphocytes in G0G1 phase of cell cycle (figure 1). However, the presence of MSC increased the viability ob B-lymphocytes (double number of viable B-cells: from 13012 to 22835 Annexin-V PE/7 ADD negative events within B-lymphocytes in absence versus presence of MSC). The exposure of B-cells to plasmocytoid DC (pDC) induced B-lymphocytes differentiation increasing both the percentage of CD38++/CD138++ cells as well as the mean fluorescence intensity of both markers (figure 2). Accordingly, different B-cell subpopulations could be identified which represented a continuum in B-cell maturation. While the levels of cytoplasmic immunoglobulin (cIg) were higher among CD38++ cells, the opposite occurred for the expression of surface Ig as well as CD19 and CCR7. Interestingly, the presence of MSC blocked B-cell differentiation. Regarding the pathways involved in these effects, the presence of MSC influenced on ERK 1/2 and p38 pathways, but these effects depended on the culture conditions. Thus, MSC induced phosphorilation of ERK 1/2 MAPK and inhibited phosphorilation of p38 in B-cells cultured with Ig plus CpG (low proliferative conditions) while the contrary occurred in B-cells cultured with TPA (highly proliferative conditions). Therefore we demonstrated that MSC increased viability and blocked cell cycle of B-lymphocytes. Furthermore the plasmocitoid dendritic cells favoured B-lymphocytes differentiation and this process in inhibited in presence with MSC. These effects are at least in part mediated through the ERK 1/2 and p38 pahtways. Figure Figure

Description: Despite the major advances in the treatment of classical Hodgkin Lymphoma (cHL) patients, around 30% to 40% of cases in advanced stages may relapse or die as result of the disease, and current markers to predict prognosis are rather unreliable. The identification of molecular events and biological processes associated with treatment failure are essential to develop new predictive tools. We used gene expression data from 29 samples of advanced cHL patients and HL-derived cell lines in order to identify transcriptional patterns from both tumoral cells and cell microenvironment. Student t-test was used to detect genes differentially overexpressed in cell lines and in tumor samples, thus creating two databases that report for genes expressed by the tumor HRS cells and genes expressed by the microenvironment. Using Gene Set Enrichment analysis (GSEA) we identified specific gene sets enriched in both databases in patients with favorable and unfavorable outcome, respectively. To validate these pathways we designed a novel Taqman low-density array (LDA) to examine the expression of the most relevant genes in 60 formalin-fixed, paraffin embedded (FFPE) tissue samples, and correlated the results with treatment outcome. Functional pathways related to unfavorable outcome significantly enriched in the HRS cells included the regulation of the G2/M checkpoint of the cell cycle, S phase and G1/S transition, chaperons, histone modification and other signaling pathways with an important representation of the MAPK pathway. On the other hand, genes reporting for specific T-cell populations (T-cytotoxic and T-regulatory cells) and macrophage activation were found to be overexpressed in the microenvironment. The final model presents a balanced representation of these genes, including also genes encoding factors implicated in drug resistance (RRM2, TYMS and TOP2A). RNA extracted from FFPE sections yielded analyzable data for 80% of samples. LDA analysis of the genes included in the model confirmed the feasibility of this approach, and the capacity for identifying cases with increased risk of failure.LDA provides an effective technique for analyzing gene expression in FFPE tissues, and it can be used for clinical prediction in diagnostic samples, using a selection of genes identified after GSEA analysis of the initial molecular signatures. This novel Taqman LDA will be used to develop a new molecular predictor of the outcome of patients with advanced cHL.

Description: Complications during induction chemotherapy (CT) for AML cause mortality in 5–20% of cases. It is relevant to define the risk of early death in this setting. In patients with a high probability of dying due to toxicity, the intensification of the supportive measures and/or alternative antineoplastic approaches could be appropriate. The aim of this study was to detect the features associated with lethal complications during induction CT for AML. We defined early deaths (ED) as those occurring before 42 days after the start of induction in the absence of evident leukemia. We analyzed all consecutive patients diagnosed with AML between June 1998 and February 2006 in 20 Spanish hospitals. These cases were treated according two multicenter trials CETLAM 99 (n=326) and CETLAM 2003 (n=248). Both schemes included idarubicin 12 mg/m2 days 1,3 and 5, etoposide 100 mg/m2 days 1–3 and cytarabine 500 mg/m2/12 hours days 1, 3, 5 and 7 as front-line treatment. In the CETLAM 2003, G-CSF (150 mg/m2 days 0–7) was added as priming therapy. The series included 574 patients, 248 (43%) female, with a median age of 48 years. Creatinine level was elevated (〉 1,2 mg/dL) in 11% of patients. The overall mortality rate during induction (ED) was 12% (n=69). 335 (58%) patients achieved a complete remission with a single course of CT, 108 (19%) a partial remission and 62 (11%) were refractory. The most common causes of death were infection (n= 28, 46%), bleeding (n=7, 11%), pulmonary failure not due to infection (n=6, 10%), and multiorgan failure (n=4, 7%). Univariate analysis showed that age older than 50 years old, male gender, M4 or M5 FAB subtype, leukocyte count higher than 100x109/L, blasts in the marrow 〉70% and creatinine level above 1,2 mg/dL were associated with more frequent ED. In multivariate analysis, elevated creatinine level [hazard ratio (HR) 2.6 (1.3–5.2); P=0.009], leukocytosis 〉100x109/L [HR 2.3 (1.1–4.6) P=0.021] and age 〉 50 years old [HR 2.1 (1.4–3.9) P=0.018] were independent risk factors. The remaining parameters, including among others the use of G-CSF, gender, blasts in the marrow, treatment protocol, cytogenetics at diagnosis and FLT-3 mutational status were not associated with higher incidence of ED. Taking into account the three significant variables identified as risk factors, we developed a scoring system to predict the probability of ED during induction. The probability of ED in the low risk (none risk factor, n=212), intermediate risk (1 risk factor, n=239) and high risk (2 or 3 risk factors, n=57) categories were 3%, 11% and 28% respectively (P

Description: Introduction: Liver metabolism has two fundamental types of enzymes. Phase two enzymes include GlutathioneS-transferases (GST), with three main variants: GST-M1, GST-T1 and GST-P1. Individual differences in these enzymes could influence their detoxificating capacity. Aim: To study the influence of several genetic GST liver enzymes variants in the development of liver Sinusoidal Obstruction Syndrome (SOS) in patients with multiple myeloma (MM) that received BUMEL as conditioning regimen for Autologous Stem Cell Transplantation (ASCT). Patients: 91 patients with MM - included in Spanish protocol Myeloma 2000 that had received BUMEL as conditioning schedule for ASCT - have been studied; 12 of them had developed SOS. 62 healthy individuals as well as 12 patients with monoclonal gammapathy of uncertain significance (MGUS) were also studied. Methods: Three genotype variants of GST enzymes were studied: presence or absence of GST-M1, GST-T1 and GST-P1 polymorphism Ile105Val by real time PCR in light cycler v2 or ABI PRISM 7900HT thermocyclers. Associations between variables were studied by X2 and exact Fisher test. Logistic regression analysis was performed to calculate Odds ratios and relative risk of SOS development. Results: Significant differences (p〉0.0001) were found in the prevalence of homozygous genotype GST-P1 Ile105Val comparing the group of patients with MM and SOS (5 of 12, 41%) and the rest of MM patients without SOS (5 of 79, 6%). This genotype was present in 17% of healthy individuals and MGUS. The genotype absence of GST-M1 was observed in 33% (4/ 12) of MM patients with SOS, 46% (37/79) of MM patients without SOS (p=0.38), 56% of controls and 71% of MGUS. The genotype absence of GST-T1 was observed in 50% (6/ 12) of MM patients with SOS, 27% (22/79) without SOS (p=012), 19% (16/62) of healthy individuals and 21% of MGUS. 33% (4/12) of MM patients with SOS presented the absence of GST-T1 genotype and the presence of homozygous GST-P1 Ile105Val and none of the patients with MM without SOS (p=0,000) presented these genotypes. The only factor associated to development of SOS in regression study was the presence of genotype GST-P1 Ile105Val in homozygosis (OR 10.57 CI 2.45–45.6 p=0.002). Conclusions: The genotype absence of GST-T1 together with the homozygous GST-P1 Ile105Val polymorphism, especially the latter, should be considered as new risk factors in the development of SOS in MM undergoing ASCT conditioning regimen with BUMEL.

Description: Abstract 3219 Poster Board III-156 Introduction Dimethylsulfoxide (DMSO) containing cryoprotective solutions are routinely used for the storage of hematopoietic progenitors (HP). At room temperature, DMSO is toxic for the cells and may produce severe adverse reactions during their infusion, especially in the pediatric patients. These problems can be avoided by washing the cells prior to the infusion. Our objective was to test if an automatic washing method (Sepax S-100, Biosafe) allowed us to preserve the CD34+ cell numbers with an adequate viability and engraftment potential. Material and Methods Forty five peripheral blood HP apheresis that have been cryopreserved using autologous plasma plus 9% DMSO were studied. After rapid thawing in a water bath at 37° C, an automatic wash with the Sepax S-100 (2 washes cycle) was performed. Nucleated cell levels determined by an hematology analyzer, flow cytometry CD34+ cell counts and Trypan Blue cell viability test were performed on aliquots collected prior to and after the washing technique. The paired Student's t-test and the Pearson's correlation coefficient were used for the statistical analysis. Results The mean total nucleated cell (TNC) and CD34+ cell recovery was 75,47% ± 3, and 94,66% ± 4,62 respectively. In spite of the TNC significant loss (p500 cells /mL) and platelet engraftment (〉50.000 cells/mL) were 11 ± 0,2 and 20 ± 1,4 days respectively. Conclusions The Sepax S-100 automatic wash protocol of DMSO containing peripheral blood progenitor cells determines a good CD34+ cell recovery and preserves their viability and engraftment potential. This method avoids the DMSO infusion related adverse events and it constitutes a closed and easy to do procedure. Disclosures No relevant conflicts of interest to declare.

Description: Membrane type 1–matrix metalloproteinase (MT1-MMP) is involved in endothelial and tumor-cell migration, but its putative role in leukocyte migration has not been characterized yet. Here, we demonstrate that anti–MT1-MMP monoclonal antibody (mAb) impaired monocyte chemotactic protein-1 (MCP-1)–stimulated monocyte migration on fibronectin (FN), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1). In addition, monocyte transmigration through tumor necrosis factor-α (TNF-α)–activated endothelium is also inhibited by anti–MT1-MMP mAb. Therefore, regulation of MT1-MMP in human peripheral blood monocytes was investigated. First, MT1-MMP clustering was observed at motility-associated membrane protrusions of MCP-1–stimulated monocytes migrating on FN, VCAM-1, or ICAM-1 and at the leading edge, together with profilin, of monocytes transmigrating through activated endothelial cells. In addition, up-regulation of MT1-MMP expression was induced in human monocytes upon attachment to FN in a manner dependent on α4β1 and α5β1 integrins. Binding of monocytes to TNF-α–activated human endothelial cells as well as to VCAM-1 or ICAM-1 also resulted in an increase of MT1-MMP expression. These findings correlated with an enhancement of MT1-MMP fibrinolytic activity in monocytes bound to FN, VCAM-1, or ICAM-1. Our data show that MT1-MMP is required during human monocyte migration and endothelial transmigration and that MT1-MMP localization, expression, and activity are regulated in monocytes upon contact with FN or endothelial ligands, pointing to a key role of MT1-MMP in monocyte recruitment during inflammation.

Description: Abstract 3660 Poster Board III-596 Introduction Despite the major advances in the treatment of classical Hodgkin Lymphoma (cHL) patients, around 30% to 40% of cases in advanced stages may relapse or die as result of the disease. Current predictive systems, based on clinical and analytical parameters, fail to identify accurately this significant fraction of patients with short failure-free survival (FFS). Transcriptional analysis has identified genes and pathways associated with clinical failure, but the biological relevance and clinical applicability of these data await further development. Robust molecular techniques for the identification of biological processes associated with treatment response are necessary for developing new predictive tools. Patients and Methods We used a multistep approach to design a quantitative RT-PCR-based assay to be applied to routine formalin-fixed, paraffin-embedded samples (FFPEs), integrating genes known to be expressed either by the tumor cells and their reactive microenvironment, and related with clinical response to adriamycin-based chemotherapy. First, analysis of 29 patient samples allowed the identification of gene expression signatures related to treatment response and outcome and the design of an initial RT-PCR assay tested in 52 patient samples. This initial model included 60 genes from pathways related to cHL outcome that had been previously identified using Gene Set Enrichment Analysis (GSEA). Second, we selected the best candidate genes from the initial assay based on amplification efficiency, biological significance and treatment response correlation to set up a novel assay of 30 genes that was applied to a large series of 282 samples that were randomly split and assigned to either estimation (194) or validation series (88). The results of this assay were used to design an algorithm, based on the expression levels of the best predictive genes grouped in pathways, and a molecular risk score was calculated for each tumor sample. Results Adequate RT-PCR profiles were obtained in 264 of 282 (93,6%) cases. Normalized expression levels (DCt) of individual genes vary considerably among samples. The strongest predictor genes were selected and included in a multivariate 10-gene model integrating four gene expression pathway signatures, termed CellCycle, Apoptosis, NF-KB and Monocyte, which are able to predict treatment response with an overall accuracy of 68.5% and 73.4% in the estimation and validation sets, respectively. Patients were stratified by their molecular risk score and predicted probabilities identified two distinct risk groups associated with clinical outcome in the estimation (5-year FFS probabilities 75.6% vs. 45.9%, log rank statistic p≈0.000) and validation sets (5-year FFS probabilities 71.4% vs. 43.5%, log rank statistic p

Description: The chimeric protein Bcr/Abl has been connected to several signalling pathways such as AKT, JNK or ERK1/2. Here, we present evidence showing that Bcr/Abl is able to modulate the p38 MAPK pathway. Transient transfection experiments indicated that over-expression of Bcr/Abl in 293T is able to activate p38 MAPK or induce p73 stabilization, suggesting that c-Abl and Bcr/Abl share some biological substrates. Interestingly, the control exerted by Bcr/Abl on the p38 MAPK pathway was not only mediated by the tyrosine kinase activity of Bcr/Abl. In fact, Bcr alone is able to induce P38 MAPK activation specifically through MKK3. Supporting these observations Chronic Myeloid Leukaemia-derived K562 cells or BaF 3 cells stably transfected with Bcr/Abl showed higher levels of phosphorylated p38 MAPK compared to Bcr/Abl-negative cells. Interestingly, Bcr/Abl-negative cells activated p38 MAPK in response to Ara-C, while Bcr/Abl-positive cells were unable to activate p38 MAPK. Furthermore, inhibition of p38 MAPK activation by SKF860002 induces a resistant phenotype in Bcr/Abl negative cells. Our results demonstrate that the interference of Bcr/Abl in the p38 MAPK pathway is a key mechanism for explaining resistance to Ara-C in Bcr/abl positive cells.

Description: BACKGROUND: Bortezomib is an useful drug for the second line treatment of Multiple Myeloma (MM). This reversible proteasome inhibitor obtains durable responses in relapsed or refractory MM, given as monotherapy or in combination, with acceptable toxicity. AIM: To analyse the overall response of bortezomib plus dexamethasone in patients with relapsed or refractory MM after treatment with vincristine, adriamycin and dexamethasone (VAD) regimens. The time to progression (TTP), time to alternative treatment (TTAT), overall survival (OS) and toxicity profile were also studied. PATIENTS AND METHODS: We conducted a retrospective study of 58 patients with relapsed or refractory MM from seven Andalusian hospitals since March 2005 until June 2008. Patients received bortezomib and dexamethasone as second line therapy after a prior treatment with VAD regimens. The patients were treated with standard bortezomib dose (1.3 mg/m2 IV bolus on days 1, 4, 8 and 11) plus dexamethasone (40 mg/d PO the same days) every 21 days, for up to 8 cycles. The mean age of our series was 57 years (range 39–66) and included 53% males. The prognostic variables at the time of diagnosis were: beta2-microglobuline 〉3,5 mg/l (57 %), albumine