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  • American Society of Hematology  (460)
  • 1
    In: Blood, American Society of Hematology, Vol. 118, No. 21 ( 2011-11-18), p. 4896-4896
    Abstract: Abstract 4896 Introduction: Chemokines are known to play an important role in the migration and survival of B-CLL cells. The non-signalling chemokine receptors, including DARC, D6 and CCX-CKR, have recently been shown to be involved in chemokine clearance and activity regulation. The human chemokine receptor CRAM is the most recently identified member of this atypical group. CRAM is expressed on B cells in a maturation-stage dependent manner, and to variable degrees on B-CLL cells. We have recently shown that it competitively binds CCL19 and that this binding is not followed by classical chemokine responses. CCL19 and its signalling receptor CCR7 are centrally involved in B cell localisation and maturation within the secondary lymphoid tissues. CCR7 is also highly expressed on B cells from CLL patients and mediates migration towards its ligands CCL19 and CCL21 which have been shown to be present at higher concentrations in serum of patients with lymphadenopathia compared to patients without. In this study we investigate the influence of CRAM on the CCL19 dependent responses of B-CLL cells and potential correlations to clinical data with a specific focus on lymphadenopathia. Results: We demonstrate that B cells from patients with B-CLL present high, but variable degrees of CCR7 and CRAM expression. Patients with compared to patients without lymphadenopathia show a higher CRAM expression level whereas the CCR7 expression is not significantly different. In single samples showing extremly high CRAM expression the migration towards CCL19 is reduced compared to patients with lower CRAM expression. These observations confirm results in the B-CLL cell line MEC-1 showing increased migration toward CCL19 when CRAM expression is reduced using CRAM-siRNA. On the other hand, CRAM seems to be a chemokine presenter as we can show that it does not degrade its chemokine ligand but presents it on the surface of polarised cell layers. Thus, we assume that CRAM plays a role for cell migration, possibly transmigration and cell localisation within lymph nodes of B-CLL cells. Conclusions: We show that CRAM can act as an integrator of different recruitment and activation factors. It is associated to CCR7 driven recruitment of B cells by regulating CCL19 availability. Expression of CRAM differs in B cell malignancies for which CCL19 and CCL21 have already been shown to be implicated in lymphadenopathia. We therefore suggest that CRAM is an additional player in the localisation and differentiation/maturation processes of malignant B cells of B-CLL patients. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2011
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    Online Resource
    Online Resource
    American Society of Hematology ; 1999
    In:  Blood Vol. 94, No. 11 ( 1999-12-01), p. 3658-3667
    In: Blood, American Society of Hematology, Vol. 94, No. 11 ( 1999-12-01), p. 3658-3667
    Abstract: Chemokines play a central role for lymphocyte trafficking and homing. The mechanisms that direct the tissue localization of B cells from patients with chronic lymphocytic leukemia (B-CLL) are unknown. We found that CLL B cells express functional CXCR4 receptors for the chemokine stromal cell-derived factor-1 (SDF-1), as demonstrated by receptor endocytosis, calcium mobilization, and actin polymerization assays. Moreover, CLL B cells displayed chemotaxis to this chemokine that could be inhibited by monoclonal antibodies (MoAbs) against CXCR4, pertussis toxin, or Wortmannin, a phosphatidylinositol 3-kinase inhibitor. That this chemotaxis may be involved in the homing of CLL cells is argued by studies in which CLL B cells were cocultured with a murine marrow stromal cell line that secretes SDF-1. Within 2 hours, CLL B cells spontaneously migrated beneath such stromal cells in vitro (pseudoemperipolesis). This migration could be inhibited by pretreatment of CLL B cells with anti-CXCR4 MoAbs, SDF-1, or pertussis-toxin. Furthermore, we noted strong downmodulation of CXCR4 on CLL B cells that migrated into the stromal cell layer. These findings demonstrate that the chemokine receptor CXCR4 on CLL B cells plays a critical role for heterotypic adherence to marrow stromal cells and provide a new mechanism to account for the marrow infiltration by neoplastic B cells.
    Type of Medium: Online Resource
    ISSN: 1528-0020 , 0006-4971
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 1999
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 3
    In: Blood, American Society of Hematology, Vol. 106, No. 5 ( 2005-09-01), p. 1824-1830
    Abstract: Growth and survival of chronic lymphocytic leukemia (CLL) B cells are favored by interactions between CLL and nontumoral accessory cells. CLL cells express CXCR4 chemokine receptors that direct leukemia cell chemotaxis. Marrow stromal cells or nurselike cells constitutively secrete CXCL12, the ligand for CXCR4, thereby attracting and rescuing CLL B cells from apoptosis in a contact-dependent fashion. Therefore, the CXCR4-CXCL12 axis represents a potential therapeutic target in CLL. We evaluated the most active CXCR4-specific antagonists (T140, TC14012, TN14003) for their capacity to inhibit CXCL12 responses in CLL cells. T140, or its analogs, inhibited actin polymerization, chemotaxis, and migration of CLL cells beneath stromal cells. CXCL12-induced phosphorylation of p44/42 mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) was abolished by CXCR4 antagonists. TC14012 and TN14003 antagonized the antiapoptotic effect of synthetic CXCL12 and stromal cell-mediated protection of CLL cells from spontaneous apoptosis. Furthermore, we found that stromal cells protected CLL cells from chemotherapy-induced apoptosis. Treatment with CXCR4 antagonists resensitized CLL cells cultured with stromal cells to fludarabine-induced apoptosis. These findings demonstrate that CXCR4 blocking agents effectively antagonize CXCL12-induced migratory and signaling responses and stromal protection of CLL cells from spontaneous or fludarabine-induced apoptosis. As such, small molecular CXCR4 antagonists may have activity in the treatment of patients with this disease. (Blood. 2005;106:1824-1830)
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2005
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 4
    In: Blood, American Society of Hematology, Vol. 96, No. 8 ( 2000-10-15), p. 2655-2663
    Abstract: A subset of blood cells from patients with B-cell chronic lymphocytic leukemia (CLL) spontaneously differentiates in vitro into large, round, or fibroblast-like adherent cells that display stromal cell markers, namely vimentin and STRO-1. These cells also express stromal cell–derived factor-1 (SDF-1), a CXC chemokine that ordinarily is secreted by marrow stromal cells. Leukemia B cells attach to these blood-derived adherent cells, down-modulate their receptors for SDF-1 (CXCR4), and are protected from undergoing spontaneous apoptosis in vitro. Neutralizing antibodies to SDF-1 inhibit this effect. Moreover, the rapid deterioration in the survival of CLL B cells, when separated from such cells, is mitigated by exogenous SDF-1. This chemokine also results in the rapid down-modulation of CXCR4 and activation of p44/42 mitogen-activated protein-kinase (ERK 1/2) by CLL B cells in vitro. It is concluded that the blood of patients with CLL contains cells that can differentiate into adherent nurse-like cells that protect leukemia cells from undergoing spontaneous apoptosis through an SDF-1–dependent mechanism. In addition to its recently recognized role in CLL B-cell migration, SDF-1–mediated CLL B-cell activation has to be considered a new mechanism involved in the microenvironmental regulation of CLL B-cell survival.
    Type of Medium: Online Resource
    ISSN: 1528-0020 , 0006-4971
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2000
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 5
    In: Blood, American Society of Hematology, Vol. 110, No. 11 ( 2007-11-16), p. 2481-2481
    Abstract: Multiple myeloma (MM) cells present with significant genetic abnormality. This genetic instability is considered responsible for not only development of malignant phenotype but also progression of myeloma as well as development of drug resistance. We have previously demonstrated that MM cell lines have elevated homologous recombination activity that leads to acquisition of new genomic changes over time and is associated with development of drug resistance (Blood2004; 104: 3409). However, such genomic evolution in patient samples has not been documented. Here, we have performed a genome wide loss of heterozygosity (LOH) assay, using high-density oligonucleotide arrays capable of measuring up to 500K single nucleotide polymorphisms (SNP) loci, and identify areas of amplification and losses to determine ongoing development of new changes that may reflect instability. We have evaluated 17 MM patients with purified myeloma cells obtained at two time points, at least six months apart. CD138–expressing myeloma cells from these patients were purified and their peripheral blood mononuclear cells were also obtained. Genomic DNA from these cells was digested with StyI, PCR amplified and hybridized to 250K SNP array. Results from CD138+ myeloma cells from two time points or more were compared with each other using the dChip software for LOH and copy number analysis. During the LOH analysis, we have adapted a tumor vs. tumor comparison to track all the new SNPs affected. We have observed that myeloma cells acquired new LOH loci in the subsequent samples. These new areas of genetic changes were recurrent; for example on chromosome 13, an average area of recurrent LOH of 87 Mb was found to be present among three patients. We were able to observe recurrence of significant copy changes on several chromosomes with/without LOH. The reproducible area of new acquisition of LOH and/or significant copy changes interestingly involved areas on chromosomes 1p, 1q, 8p, 9q, 13q, 15, 16q, 20p, 21q, and X that may have significant role in the pathogenesis and progression of the disease. We are currently analyzing the gene expression profile from these time points to identify expression changes correlating with the observed genomic changes on follow up samples. In summary we demonstrate continued acquisition of new genomic changes in vivo in MM over time and provide a molecular basis for evolution of more aggressive disease able to escape therapeutic interventions. The mechanism governing such evolution is an important target to not only inhibit progression of the disease but also development of drug resistance.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2007
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 6
    Online Resource
    Online Resource
    American Society of Hematology ; 1999
    In:  Blood Vol. 94, No. 11 ( 1999-12-01), p. 3658-3667
    In: Blood, American Society of Hematology, Vol. 94, No. 11 ( 1999-12-01), p. 3658-3667
    Abstract: Chemokines play a central role for lymphocyte trafficking and homing. The mechanisms that direct the tissue localization of B cells from patients with chronic lymphocytic leukemia (B-CLL) are unknown. We found that CLL B cells express functional CXCR4 receptors for the chemokine stromal cell-derived factor-1 (SDF-1), as demonstrated by receptor endocytosis, calcium mobilization, and actin polymerization assays. Moreover, CLL B cells displayed chemotaxis to this chemokine that could be inhibited by monoclonal antibodies (MoAbs) against CXCR4, pertussis toxin, or Wortmannin, a phosphatidylinositol 3-kinase inhibitor. That this chemotaxis may be involved in the homing of CLL cells is argued by studies in which CLL B cells were cocultured with a murine marrow stromal cell line that secretes SDF-1. Within 2 hours, CLL B cells spontaneously migrated beneath such stromal cells in vitro (pseudoemperipolesis). This migration could be inhibited by pretreatment of CLL B cells with anti-CXCR4 MoAbs, SDF-1, or pertussis-toxin. Furthermore, we noted strong downmodulation of CXCR4 on CLL B cells that migrated into the stromal cell layer. These findings demonstrate that the chemokine receptor CXCR4 on CLL B cells plays a critical role for heterotypic adherence to marrow stromal cells and provide a new mechanism to account for the marrow infiltration by neoplastic B cells.
    Type of Medium: Online Resource
    ISSN: 1528-0020 , 0006-4971
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 1999
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 7
    In: Blood, American Society of Hematology, Vol. 96, No. 8 ( 2000-10-15), p. 2655-2663
    Abstract: A subset of blood cells from patients with B-cell chronic lymphocytic leukemia (CLL) spontaneously differentiates in vitro into large, round, or fibroblast-like adherent cells that display stromal cell markers, namely vimentin and STRO-1. These cells also express stromal cell–derived factor-1 (SDF-1), a CXC chemokine that ordinarily is secreted by marrow stromal cells. Leukemia B cells attach to these blood-derived adherent cells, down-modulate their receptors for SDF-1 (CXCR4), and are protected from undergoing spontaneous apoptosis in vitro. Neutralizing antibodies to SDF-1 inhibit this effect. Moreover, the rapid deterioration in the survival of CLL B cells, when separated from such cells, is mitigated by exogenous SDF-1. This chemokine also results in the rapid down-modulation of CXCR4 and activation of p44/42 mitogen-activated protein-kinase (ERK 1/2) by CLL B cells in vitro. It is concluded that the blood of patients with CLL contains cells that can differentiate into adherent nurse-like cells that protect leukemia cells from undergoing spontaneous apoptosis through an SDF-1–dependent mechanism. In addition to its recently recognized role in CLL B-cell migration, SDF-1–mediated CLL B-cell activation has to be considered a new mechanism involved in the microenvironmental regulation of CLL B-cell survival.
    Type of Medium: Online Resource
    ISSN: 1528-0020 , 0006-4971
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2000
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 8
    Online Resource
    Online Resource
    American Society of Hematology ; 2004
    In:  Blood Vol. 104, No. 11 ( 2004-11-16), p. 4347-4347
    In: Blood, American Society of Hematology, Vol. 104, No. 11 ( 2004-11-16), p. 4347-4347
    Abstract: The Kaposi’s sarcoma herpesvirus encodes a G-protein-coupled chemokine receptor termed KSHV-GPCR. Expression of this constitutively active GPCR leads to cell transformation and vascular overgrowth characteristic of Kaposi’s sarcoma. Previously, we have shown that CXCR2, the closest human homologue, is similarly able to transform cells if continously stimulated or constitutively activated by amino acid exchange D138V of the DRY sequence. Here, we demonstrate that STAT3 activation is a prerequisite for transformation in KSHV-GPCR and CXCR2 transfected NIH 3T3 cells. In KSHV-GPCR and D138V transfected cells, STAT-3 is constitutively phosphorylated on Tyr705. In CXCR2 transfected NIH 3T3 cells and human microvascular endothelial cells (HMEC), which express the CXCR2 constitutively, STAT3 is phosphorylated upon stimulation with IL-8 (CXCL8). Focus formation in NIH 3T3 cells transfected with the KSHV-GPCR, CXCR2, or the D138V mutant, was blocked by the specific JAK2 inhibitor AG490. Typical functions of the CXCR2 including actin stress fiber formation, haptotaxis, and the angiogenic response in HMEC shown by tube formation in Matrigel were blocked by AG490. These data suggest that the transforming capacity and migratory responses that are involved in tumor development, metastasis and angiogenesis in KSHV or CXCR2-expressing cells is at least partially mediated through a JAK2-STAT3 dependent pathway.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2004
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 9
    In: Blood, American Society of Hematology, Vol. 112, No. 11 ( 2008-11-16), p. 2094-2094
    Abstract: Prognostic factors are important for evaluating patients (pts) with CLL, owing to heterogeneity in response to treatment and clinical course. The goal of this analysis was to evaluate the newer prognostic factors in relation to traditional ones in previously untreated pts receiving frontline chemoimmunotherapy. Traditional prognostic factors include age, Rai stage, absolute lymphocyte count (ALC), lymphocyte doubling time, and many others. Newer prognostic factors, include IgVH gene mutation status (MS), chromosome abnormalities by FISH, and leukemia cell expression of ZAP70. Finally, the clinical endpoint is important in considering and evaluating prognostic factors, since significant independent factors can be different for response to treatment, time to progression (TTP), and overall survival (OS). We evaluate 488 previously untreated pts who had an NCI-WG ‘96 indication for treatment and received frontline chemoimmunotherapy (CIT). Treatment was with a fludarabinebased CIT regimen: FCR (n=300), FCMR (n=30), FCR3 (n=65), FCR+GM-CSF (n=45), or CFAR (n=48). The CR rate, TTP, and OS were not significantly different between the CIT regimens; median follow-up times varied. The overall estimated median follow-up time was 62mo, TTP was 76mo, and OS was not reached. An extensive list of pretreatment characteristics were evaluated in univariable analyses as traditional factors including age, Rai stage, beta-2 microglobulin (β2M), CD38, and others, as well as newer prognostic factors including chromosome abnormalities by FISH, IgVH MS and ZAP70 expression by immunohistochemistry. Clinical endpoints included complete remission (CR), TTP, and OS. Multiple factors were significant (p & lt;.05) and varied according to clinical endpoint. Next, we evaluated these significant factors in multivariable (MV) analyses to identify the significant (p & lt;.05) independent factors for each endpoint. The rank order importance for each independent factor identified in the MV model with current follow-up is shown (Table 1). Table 1 Multivariable Model CR TTP OS We evaluated the newer prognostic factors (IgVH MS, del 17p, and ZAP70) separately in each final MV model to assess significant (p & lt;.05) independent correlations (Table 2). # Pts in Model 483 301 483 # Events 351 101 106 Characteristic Rank-Order Significance in MV Model β2M 1 - 1 Hemoglobin 2 - - Age - 2 2 CD38 (30% cut point) - 3 - IgVH MS - 1 - Table 2 Significance of Factor in MV Model Characteristic CR TTP OS When including del 17p in models for TTP and OS, age and IgVH MS were no longer significant. Continued follow-up may identify additional important factors for time-toevent endpoints. Nomograms will be developed for each endpoint and full analyses will be shown. These analyses enable us to generate expectations and help in evaluating efficacy of new regimens for patients going on frontline CIT. Age, β2M, and del 17p appear to be the most important independent factors for OS in previously untreated patients who receive frontline CIT. Considering the newer prognostic factors, β2M continues to remain a major, independent, significant prognostic factor. Del 17p p & lt;.05 p & lt;.05 p & lt;.05 IgVH MS Not Sig. p & lt;.05 Not Sig. ZAP70 Not Sig. p & lt;.05 p & lt;.05
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2008
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 10
    In: Blood, American Society of Hematology, Vol. 112, No. 11 ( 2008-11-16), p. 2985-2985
    Abstract: Background: Hypomethylating agents are approved for the treatment of myelodysplastic syndrome (MDS) and have activity in acute myelogenous leukemia (AML) (Issa, JP et al. Blood. 2004;103:1635–40)(Silverman LR et al. Journal of Clinical Oncology2006; 24: 3895–3903). Exposure of AML cells to hypomethylating agents increase their CD33 expression (Balain and Ball. Leukemia. 2006; 20:2093–2101). This establishes a rationale for the combination of hypomethylating agent with CD33 antibody for treatment of high-risk MDS and AML. A preliminary report of the combination of 5-azacitidine (Aza) and gemtuzumab ozogamicin (GO) in elderly patients with previously untreated AML and MDS showed promise (Nand, S. et al. Blood2006;108: Abstract 1981). Patients and Method: We have started enrolling patients in a phase 2 study of Decitabine (DAC) with GO in patients with AML and high-risk myelodysplastic syndrome (MDS). Treatment includes DAC 20 mg/m2/day intravenously (IV) × 5 days and GO 3 mg/m2 IV on day 5. GO is repeated on day 15±2 of first cycle if peripheral blood blast count is & gt; 109/L. Six such cycles are planned every 4–8 weeks. Patients achieving clinically relevant response e.g. complete remission (CR), CR with incomplete platelet recovery (CRp), marrow clearance/reduction of blasts etc. can continue on DAC alone approximately every 4–8 weeks for up to 24 cycles of total therapy duration. Based on historical expectations patients are divided into four groups according to study design: relapsed AML 1st CR duration & lt;= 1 year or beyond first relapse, relapsed AML 1st CR duration & gt; 1 year, untreated AML (not eligible for standard induction)/MDS, previously treated MDS, secondary MDS or AML. Results: Thirty-seven patients have been treated till date; Group 1=19, group 2=1, Group 3=12 and group 4=5. Median age is 63.5 years (range, 26–82), performance status =1 (range, 0–3), prior therapy =1 (range, 0–7). Eighteen (49%) patients has adverse cytogenetics and 14 (38%) has prior malignancies. Two patients received day 15±2 administration of GO. Median number of treatment cycles is 2 (range, 1–5). Eight patients died while on study. Except for cytopenias, infections, infusion related reactions etc. no significant grade 3/4 toxicities have been encountered. Three patients have achieved CR/CRp and 5 patients achieved other clinically relevant responses with an overall response rate of 22%. Responses according to patient groups are; Group 1=2/19 (4 ongoing), group 2=1/1, group 3=2/12 (3 ongoing), group 4=3/5. Seven additional patients are continuing on study with stable disease. Accrual to the study is ongoing. Conclusion: The combination of DAC and GO appears promising particularly in less heavily pre-treated patients with high-risk MDS and AML.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2008
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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