Biomedical subjects

Reinhard Andreesen

Publications and source records attributed to Reinhard Andreesen.

At least 37 records · Page 2Linked to original sources

PubMed2005

Tumor-derived lactic acid modulates dendritic cell activation and antigen expression.

The tumor milieu can influence dendritic cell (DC) differentiation. We analyzed DC differentiation in a 3-dimensional tumor model and propose a new mechanism of DC modulation by the tumor environment. Monocytes were cultured in the presence of IL-4 and GM-CSF within multicellular tumor spheroids (MCTSs) generated from different tumor cell lines. Monocytes invaded the MCTSs and differentiated into tumor-associated dendritic cells (TADCs). The antigen expression was altered on TADCs independent of the culture conditions (immature/mature DCs, Langerhans cells) and IL-12 secretion was reduced. Supernatants of MCTSs could partially transfer the suppressive effect. Conditioned media from urothelial carcinoma cell lines contained high levels of M-CSF and IL-6, both cytokines known to modulate DC differentiation. In contrast, melanoma and prostate carcinoma MCTS cocultures produced little M-CSF and IL-6, but high levels of lactic acid. Indeed, addition of lactic acid during DC differentiation in vitro induced a phenotype comparable with TADCs generated within melanoma and prostate carcinoma MCTSs. Blocking of lactic acid production in melanoma MCTS cocultures reverted the TADC phenotype to normal. We therefore conclude that tumor-derived lactic acid is an important factor modulating the DC phenotype in the tumor environment, which may critically contribute to tumor escape mechanisms.

Cell Differentiation↗

PubMed2005

Peripheral dendritic cell chimerism in allogeneic hematopoietic stem cell recipients.

BACKGROUND: Relapse and graft-versus-host disease (GVHD) represent major causes of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (HSCT). Although leukocyte and T-cell chimerism analyses are performed routinely suggesting a predictive value on the patients outcome, little is known about chimerism of dendritic cells (DC) representing strong initiators of immune responses. METHODS: In this prospective study, peripheral DC1 (CD11c+) and DC2 (CD123+) chimerism was determined in hematopoetic stem cell recipients. DCs were isolated from peripheral blood by fluorescence activated cell sorting. Chimerism analyses were performed by fluorescent in situ hybridization or by polymerase chain reaction-based typing of short tandem repeats. RESULTS: At time of engraftment, DC chimerism analyses showed complete chimerism in 76.3% (DC1)/79.5% (DC2), mixed chimerism (MC) in 21.0% (DC1)/17.9% (DC2) and no chimerism in 2.7% (DC1)/2.6% (DC2) of the patients. Peripheral DC chimerism had no significant effect on relapse-free or overall survival. Although acute GVHD was observed more often in patients with MC for DC1/DC2 and chronic GVHD occurred more often in patients with MC for DC2, there was no statistically significant correlation. CONCLUSIONS: Although DCs as antigen presenting cells are supposed to have an impact on the induction of GVHD, there was no significant correlation between incidence of GVHD and DC chimerism after HSCT.

Adolescent↗

PubMed2005

Transcription factor Tfec contributes to the IL-4-inducible expression of a small group of genes in mouse macrophages including the granulocyte colony-stimulating factor receptor.

Expression of the mouse transcription factor EC (Tfec) is restricted to the myeloid compartment, suggesting a function for Tfec in the development or function of these cells. However, mice lacking Tfec develop normally, indicating a redundant role for Tfec in myeloid cell development. We now report that Tfec is specifically induced in bone marrow-derived macrophages upon stimulation with the Th2 cytokines, IL-4 and IL-13, or LPS. LPS induced a rapid and transient up-regulation of Tfec mRNA expression and promoter activity, which was dependent on a functional NF-kappaB site. IL-4, however, induced a rapid, but long-lasting, increase in Tfec mRNA, which, in contrast to LPS stimulation, also resulted in detectable levels of Tfec protein. IL-4-induced transcription of Tfec was absent in macrophages lacking Stat6, and its promoter depended on two functional Stat6-binding sites. A global comparison of IL-4-induced genes in both wild-type and Tfec mutant macrophages revealed a surprisingly mild phenotype with only a few genes affected by Tfec deficiency. These included the G-CSFR (Csf3r) gene that was strongly up-regulated by IL-4 in wild-type macrophages and, to a lesser extent, in Tfec mutant macrophages. Our study also provides a general definition of the transcriptome in alternatively activated mouse macrophages and identifies a large number of novel genes characterizing this cell type.

Animals↗

PubMed2005

A role for CD54 (intercellular adhesion molecule-1) in leukocyte recruitment to the lung during the development of experimental idiopathic pneumonia syndrome.

BACKGROUND: Idiopathic pneumonia syndrome (IPS) is a frequently fatal complication of allogeneic bone marrow transplantation (BMT). IPS is associated with elevated bronchoalveolar lavage (BAL) fluid levels of tumor necrosis factor-alpha and lipopolysaccharide, both of which are potent activators of endothelial cells (ECs). EC expression of the adhesion molecule CD54 (intercellular adhesion molecule [ICAM]-1) has been shown to be a major regulator of pulmonary inflammation in various experimental models. METHODS: Using a well-established murine BMT system in which lung injury and graft-versus-host disease (GvHD) are induced by minor histocompatibility antigenic differences between donor and host, the RNase Protection Assay, mice deficient in ICAM-1 expression, and a monoclonal blocking antibody to ICAM, we evaluated the role of the pulmonary vascular expression of CD54 in the development of IPS. RESULTS: Enhanced pulmonary vascular expression of ICAM-1 coincided with the development of IPS. When ICAM-1 -/- mice were used as allogeneic BMT recipients, IPS severity (measured by lung histopathology, BAL cellularity, and cytokine expression) was significantly reduced compared with wild-type controls. Similar results were also observed when wild-type recipients were treated with a monoclonal blocking antibody to ICAM-1. Surprisingly, ICAM-1 had differential effects on leukocyte infiltration into GvHD target organs; ICAM-1 deficiency had no impact on intestinal histopathology, whereas ICAM-1-/- BMT recipients had significantly enhanced hepatic injury. CONCLUSIONS: These data demonstrate that although the expression of ICAM-1 is critical for the development of IPS, different mechanisms of leukocyte recruitment are operative in other GvHD target organs.

Animals↗

PubMed2005

Reverse signalling of membrane-integrated tumour necrosis factor differentially regulates alloresponses of CD4+ and CD8+ T cells against human microvascular endothelial cells.

Reverse signalling of membrane-integrated ligands is a common phenomenon in the tumour necrosis factor (TNF) family and contributes to the pleiotropy of this pro-inflammatory cytokine and to the plasticity of the immune system in general. Transmembrane TNF (mTNF) itself can induce resistance to bacterial endotoxin in monocytes and can stimulate the immune activity of mitogen-activated, as well as of virus-infected, T cells. The aim of the present study was to investigate the influence of reverse signalling of mTNF on the allogeneic activity of CD4+ and CD8+ T cells against human microvascular endothelial cells (HMEC), as targets of various inflammatory responses. The proliferative potential of CD4+ T cells towards HMEC was attenuated by mTNF signalling, whereas stimulation of mTNF on CD8+ T cells increased their cytotoxic potential against HMEC. These effects were specific for reverse signalling of mTNF, as a blockade of the classical TNF-TNF receptor interaction by a neutralizing TNF receptor antibody had no effect. Cytokine profiling of the effector cells revealed that the anti-endothelial CD4+ T cells were of a T helper 2 (Th2) phenotype, whereas CD8+ T cells mainly produced cytotox. T cell 1 (Tc1) cytokines. From the results obtained in this study, we conclude that reverse signalling of mTNF differentially modulates CD4+ and CD8+ T-cell activity against allogeneic endothelial cells, which should be taken into account in settings of therapeutic cytokine antagonisms.

CD4-Positive T-Lymphocytes↗

PubMed2004

Isolation and characterization of human antigen-specific TCR alpha beta+ CD4(-)CD8- double-negative regulatory T cells.

Down-regulation of immune responses by regulatory T (Treg) cells is an important mechanism involved in the induction of tolerance to allo-antigens (Ags). Recently, a novel subset of Ag-specific T-cell receptor (TCR)alpha beta+ CD4(-)CD8- (double-negative [DN]) Treg cells has been found to be able to prevent the rejection of skin and heart allografts by specifically inhibiting the function of antigraft-specific CD8+ T cells. Here we demonstrate that peripheral DN Treg cells are present in humans, where they constitute about 1% of total CD3+ T cells, and consist of both naive and Ag-experienced cells. Similar to murine DN Treg cells, human DN Treg cells are able to acquire peptide-HLA-A2 complexes from antigen-presenting cells by cell contact-dependent mechanisms. Furthermore, such acquired peptide-HLA complexes appear to be functionally active, in that CD8+ T cells specific for the HLA-A2-restricted self-peptide, Melan-A, became sensitive to apoptosis by neighboring DN T cells after acquisition of Melan-A-HLA-A2 complexes and revealed a reduced proliferative response. These results demonstrate for the first time that a sizable population of peripheral DN Treg cells, which are able to suppress Ag-specific T cells, exists in humans. DN Treg cells may serve to limit clonal expansion of allo-Ag-specific T cells after transplantation.

Antigen-Presenting Cells↗

PubMed2004

Pioglitazone and rofecoxib combined with angiostatically scheduled trofosfamide in the treatment of far-advanced melanoma and soft tissue sarcoma.

BACKGROUND: Combined treatment approaches targeting tumor cells as well as stromal cells may control chemorefractory malignancies. In the current study, the authors sought to test one such combined approach in the treatment of chemorefractory melanoma and soft tissue sarcoma. METHODS: A Phase II trial was initiated to analyze the activity of a continuously administered molecularly targeted treatment regimen (daily pioglitazone [45 mg administered orally] and rofecoxib [25 mg administered orally]) combined with sequentially added angiostatic chemotherapy for patients with previously treated metastatic melanoma (n = 19) or soft tissue sarcoma (n = 21). Angiostatic chemotherapy consisted of trofosfamide (50 mg) administered orally 3 times daily beginning on the 15th day after the start of molecularly targeted therapy. RESULTS: Forty patients were evaluable for response and toxicity. Major side effects (World Health Organization Grade 3 or 4) were not observed. Objective responses and disease stabilization lasting longer than 6 months were noted in 11% and 11%, respectively, of all patients with melanoma and in 19% and 14%, respectively, of all patients with soft tissue sarcoma. Complete remission was noted in one patient with melanoma and in three patients with sarcoma. Both normal C-reactive protein (CRP) levels and CRP levels that decreased by > 30% during the 14-day biomodulator pretreatment period were found to be predictive of prolonged progression-free survival. CONCLUSIONS: To our knowledge, the current study is the first to demonstrate that a novel, completely orally administered combined biomodulator/metronomic chemotherapy regimen may be active and well tolerated in patients with chemorefractory malignancies.

Administration, Oral↗

PubMed2004

Effect of different tumor necrosis factor (TNF) reactive agents on reverse signaling of membrane integrated TNF in monocytes.

Reverse signaling of transmembrane TNF (mTNF) contributes to the versatility of this cytokine superfamily. Previously, we could demonstrate that mTNF acting as receptor confers resistance to bacterial lipopolysaccharide in monocytes and macrophages (MO/MPhi). Reverse signaling can be induced by incubation with the monoclonal anti-TNF antibody 195F and other TNF antagonists, such as the humanized monoclonal antibody infliximab and the humanized soluble TNF receptor construct etanercept, respectively, all in former or present clinical use. Here, we addressed the question whether there are differences in modulating the LPS response in MO/MPhi among these three antagonists. Whereas 195F and infliximab suppress both, the release of an LPS-induced endothelial cell apoptotic factor and proinflammatory cytokines, etanercept only protected against the LPS-triggered apoptosis activity, but left the LPS-induced cytokine release unchanged. These data could have clinical impact with regard to TNF neutralization strategies.

Apoptosis↗

PubMed2004

Impact of thrombophilic gene mutations and graft-versus-host disease on thromboembolic complications after allogeneic hematopoietic stem-cell transplantation.

BACKGROUND: Hemostatic events in patients undergoing allogeneic hematopoietic stem-cell transplantation (HSCT) increase the morbidity and mortality in this cohort. Little is known about the impact of graft-versus-host disease (GvHD) or of thrombophilic gene mutations/polymorphisms on these complications. STUDY DESIGN: Eighty-nine allogeneic stem-cell recipients and their donors were evaluated prospectively for the presence of the factor V G1691A mutation, the prothrombin G20210A mutation, the 5,10-methylenetetrahydrofolate-reductase (MTHFR) C677T mutation, the glycoprotein IIIa PI(a1/a2) polymorphism, the fibrinogen-beta-chain 455G/A polymorphism, the plasminogen activator inhibitor-1 -675 4G/5G polymorphism, and the angiotensin-converting enzyme intron 16 I/D polymorphism. These mutations/polymorphisms and GvHD parameters were correlated to hemostatic and toxic complications after transplantation. The data were compared with those of 128 healthy controls. RESULTS: The PAI-1 4G/4G polymorphism increases the risk for catheter thrombosis after HSCT 5.7-fold (32.2% vs. 71.4%, P<0.05). In patients with hepatic veno-occlusive disease, the frequency of the PAI-1 4G allele is also increased (83.3% vs. 55.1%, NS). Thrombophilic mutations/polymorphisms in donors do not influence complications in the corresponding recipients. The MTHFR TT genotype does not modify severity and duration of mucositis and aplasia in patients receiving methotrexate prophylaxis. Patients with chronic GvHD have a higher risk of thromboembolism (12.9% vs. 1.7%, P<0.05). CONCLUSION: Thrombophilic gene mutations have only a moderate influence on hemostatic complications in patients undergoing HSCT. This may be because of the overwhelming immunologic impact of GvHD on hemostasis in the allogeneic transplantation setting.

Adolescent↗

PubMed2004

High frequency of functionally active Melan-a-specific T cells in a patient with progressive immunoproteasome-deficient melanoma.

Tumor-reactive T cells play an important role in cancer immunosurveillance. Applying the multimer technology, we report here an unexpected high frequency of Melan-A-specific CTLs in a melanoma patient with progressive lymph node metastases, consisting of 18 and 12.8% of total peripheral blood and tumor-infiltrating CD8+ T cells, respectively. Melan-A-specific CTLs revealed a high cytolytic activity against allogeneic Melan-A-expressing target cells but failed to kill the autologous tumor cells. Loading of the tumor cells with Melan-A peptide reversed the resistance to killing, suggesting impaired function of the MHC class I antigen processing and presentation pathway. Mutations of the coding region of the HLA-A2 binding Melan-A26-35 peptide or down-regulation of the MHC class I heavy chain, the antigenic peptide TAP, and tapasin could be excluded. However, PCR and immunohistochemical analysis revealed a deficiency of the immunoproteasomes low molecular weight protein 2 and low molecular weight protein 7 in the primary tumor cells, which affects the quantity and quality of generated T-cell epitopes and might explain the resistance to killing. This is supported by our data, demonstrating that the resistance to killing can be partially reversed by pre-exposure of the tumor cells to IFN-gamma, which is known to induce the immunoproteasomes. Overall, this is the first report of an extremely high frequency of tumor-specific CTLs that exhibit competent T-cell-effector functions but fail to lyse the autologous tumor cells. Immunotherapeutic approaches should not only focus on the induction of a robust antitumor immune response, but should also have to target tumor immune escape mechanisms.

Antigens, Neoplasm↗

PubMed2004

Treatment of colon and lung cancer patients with ex vivo heat shock protein 70-peptide-activated, autologous natural killer cells: a clinical phase i trial.

PURPOSE: The 14 amino acid sequence (aa(450-463)) TKDNNLLGRFELSG (TKD) of heat shock protein 70 (Hsp70) was identified as a tumor-selective recognition structure for natural killer (NK) cells. Incubation of peripheral blood lymphocyte cells with TKD plus low-dose interleukin 2 (IL-2) enhances the cytolytic activity of NK cells against Hsp70 membrane-positive tumors, in vitro and in vivo. These data encouraged us to test tolerability, feasibility, and safety of TKD-activated NK cells in a clinical Phase I trial. EXPERIMENTAL DESIGN: Patients with metastatic colorectal cancer (n = 11) and non-small cell lung cancer (n = 1) who had failed standard therapies were enrolled. After ex vivo stimulation of autologous peripheral blood lymphocytes with Hsp70-peptide TKD (2 microg/ml) plus low-dose IL-2 (100 units/ml), TKD was removed by extensive washing, and activated cells were reinfused i.v. The procedure was repeated for up to six cycles, applying a dose escalation schedule in 4 patients. RESULTS: The percentage of activated NK cells in the reinfused leukapheresis products ranged between 8 and 20% of total lymphocytes, corresponding to total NK cell counts of 0.1 up to 1.5 x 10(9). Apart from restless feeling in 1 patient and itching in 2 patients, no negative side effects were observed. Concomitant with an enhanced CD94 cell surface density, the cytolytic activity of NK cells against Hsp70 membrane-positive colon carcinoma cells was enhanced after TKD/IL-2 stimulation in 10 of 12 patients. Concerning tumor response, 1 patient was in stable disease during therapy by formal staging criteria and another patient showed stable disease in one metastases and progression in another. CONCLUSIONS: Reinfusion of Hsp70-activated autologous NK cells is safe. Immunological results warrant additional studies in patients with lower tumor burden.

Adult↗

PubMed2004

Both donor and recipient NOD2/CARD15 mutations associate with transplant-related mortality and GvHD following allogeneic stem cell transplantation.

Single nucleotide polymorphisms (SNPs) of the NOD2/CARD15 gene resulting in a diminished nuclear factor-kappaB (NF-kappaB) response to bacterial cell wall products have been associated with an increased incidence of Crohn disease. To assess a possible contribution of NOD2/CARD15 mutations to graft-versus-host disease (GvHD) and complications following allogeneic stem cell transplantation, we retrospectively typed DNA from donor/recipient pairs in 169 consecutive patients receiving transplants from related or unrelated donors. Mutated alleles were observed in 21% of patients and in 14% of donors. Cumulative incidence of 1-year, transplant-related mortality rose from 20% in donor/recipient pairs without mutated SNPs to 49% in pairs with recipient mutations (P =.03) and 59% in pairs with donor mutations (P <.005), and was highest in 12 pairs with mutated alleles in both donor and recipients (83%; P <.001). Similar associations were observed for severe overall and severe gastrointestinal GvHD. The impact of NOD2/CARD15 mutations was more prominent for HLA-identical sibling transplantations but was also observed in unrelated donor transplantation. Mutations proved to be independent risk factors for transplant-related mortality. Our findings indicate a major role of monocyte/macrophage dysfunction in the pathophysiology of GvHD and strongly suggest a future risk assessment or even donor selection through NOD2/CARD15 typing.

Adolescent↗

PubMed2004

Large-scale in vitro expansion of polyclonal human CD4(+)CD25high regulatory T cells.

CD4(+)CD25+ regulatory T (Treg) cells are pivotal for the maintenance of self-tolerance, and their adoptive transfer gives protection from autoimmune diseases and pathogenic alloresponses after solid organ or bone marrow transplantation in murine model systems. In vitro, human CD4(+)CD25+ Treg cells display phenotypic and functional characteristics similar to those of murine CD4(+)CD25+ Treg cells: namely, hyporesponsiveness to T-cell receptor (TCR) stimulation and suppression of CD25- T cells. Thus far, the detailed characterization and potential clinical application of human CD4(+)CD25+ Treg cells have been hampered by their paucity in peripheral blood and the lack of appropriate expansion protocols. Here we describe the up to 40 000-fold expansion of highly purified human CD4(+)CD25high T cells in vitro through the use of artificial antigen-presenting cells for repeated stimulation via CD3 and CD28 in the presence of high-dose interleukin 2 (IL-2). Expanded CD4(+)CD25high T cells were polyclonal, maintained their phenotype, exceeded the suppressive activity of freshly isolated CD4(+)CD25high T cells, and maintained expression of the lymph node homing receptors L-selectin (CD62L) and CCR7. The ability to rapidly expand human CD4(+)CD25high Treg cells on a large scale will not only facilitate their further exploration but also accelerate their potential clinical application in T cell-mediated diseases and transplantation medicine.

Animals↗

PubMed2004

Probiotic effects on experimental graft-versus-host disease: let them eat yogurt.

Acute graft-versus-host disease (aGVHD) often limits feasibility and outcome of allogeneic bone marrow transplantation. Current pathophysiologic concepts of aGVHD involve conditioning regimens, donor-derived T cells, proinflammatory cytokines, and bacterial lipopolysaccharide (LPS) as a major trigger for aGVHD. LPS derives mostly from gram-negative bacteria and can enter circulation through the impaired mucosal barrier after the conditioning regimen. Probiotic microorganisms have been shown to alter the composition of the intestinal microflora and thereby mediate anti-inflammatory effects. We hypothesized that modifying the enteric flora using the probiotic microorganism Lactobacillus rhamnosus GG, would ameliorate aGVHD. Here we show that oral administration of Lactobacillus rhamnosus GG before and after transplantation results in improved survival and reduced aGVHD. Furthermore, subculturing of mesenteric lymph node tissue revealed a reduced translocation of enteric bacteria. Our findings suggest that alteration of the intestinal microflora plays an important role in the initiation of experimental aGVHD.

Animals↗

PubMed2004

Microsatellite instability predicts poor short-term survival in patients with advanced breast cancer after high-dose chemotherapy and autologous stem-cell transplantation.

PURPOSE: The purpose is to define molecular prognostic factors in patients with advanced breast cancer treated with high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT). EXPERIMENTAL DESIGN: Thirty-nine patients with breast cancer and extensive lymph node (level III) and/or systemic metastases from a prospective single-center study of sequential HDCT/ASCT were studied. Microsatellite analysis was performed after laser microdissection using 15 markers selected for sensitive detection of microsatellite instability (MSI) in breast cancer. Exons 5-9 of the P53 gene were directly sequenced. Expression of P53, HER-2/neu, and the mismatch repair proteins hMSH2 and hMLH1 was evaluated by immunohistochemistry. RESULTS: MSI of at least three markers was detected in 13 of 39 patients (33%) and was predominantly found at tetranucleotide markers. All MSI-positive tumors showed normal expression of hMSH2 and hMLH1. Complete sequence analysis of exons 5-9 of the P53 gene was successful in 34 cases; 18% (n = 6) revealed a mutation. Overexpression of HER-2/neu and P53 was observed in 7 (22%) and 12 (46%) of 26 evaluated cases, respectively. The presence of MSI strongly correlated with shorter overall survival (OS; P = 0.0004) and progression-free survival (PFS; P = 0.02). None of the other investigated clinical or molecular factors correlated with OS in univariate analyses, with the exception of menopausal status and previous adjuvant chemotherapy. Testing various multivariate Cox regression models, MSI remained a highly significant, independent, and adverse risk factor for OS. CONCLUSIONS: MSI is frequent in advanced breast cancer and could be an indicator of chemotherapy resistance and poor prognosis in breast cancer patients treated with HDCT/ASCT.

Adult↗

PubMed2004

Induction of heme oxygenase-1 before conditioning results in improved survival and reduced graft-versus-host disease after experimental allogeneic bone marrow transplantation.

Acute graft-versus-host disease (aGVHD) remains one of the main obstacles after allogeneic bone marrow transplantation (BMT). Using a well-established mouse BMT model in which aGVHD is induced across a haploidentical mismatch, we show that the expression of heme oxygenase-1 (HO-1) can be induced by cobalt-protoporphyrin IX (CoPP) in aGVHD target organs such as liver and bowel and that the induction of HO-1 before BMT results in improved overall survival and reduced aGVHD. Serum levels of proinflammatory cytokines were markedly reduced in CoPP-treated animals. Recipients displayed less damage to the intestinal mucosa, and this resulted in reduced serum lipopolysaccharide levels at day 6 after transplantation. Peritoneal cells and CD45(+) liver cells isolated from mice that received transplants strongly expressed HO-1 and displayed a reduction in the expression of activation markers such as CD11b, CD80, and major histocompatibility complex class I. This resulted in reduced T-cell activation ex vivo. These results demonstrate that the induction of HO-1 before high-dose conditioning protects the host in multiple ways and effectively ameliorates aGVHD.

Animals↗

PubMed2004

Expression and function of homing-essential molecules and enhanced in vivo homing ability of human peripheral blood-derived hematopoietic progenitor cells after stimulation with stem cell factor.

Hematopoietic stem cell (HSC) homing from blood to bone marrow is a multistep process involving rolling, extravasation, migration, and finally adhesion in the correct microenvironment. With view to the hematopoietic recovery after clinical stem cell transplantation, we investigated the effect of stem cell factor (SCF) on the expression and the adhesive function of the alpha4beta1 and alpha5beta1 integrins very-late antigen (VLA)-4 and VLA-5 on peripheral blood-derived hematopoietic progenitor cells. After SCF stimulation, the expression of VLA-4 and VLA-5 on CD34+/c-kit+ cells obtained from healthy donors increased from 54% to 90% and from 3% to 82%, respectively. For patient-derived cells, the increase was 67% to 90% and 12% to 46%. The proportion of mononuclear cells adhering to the fibronectin fragment CH296 increased by stimulation with SCF from 14% to 23%. Accordingly, functional studies showed an approximate 30% increase of adherent long-term culture-initiating cell. The improvement of the homing abilities of SCF-stimulated HSC was confirmed by transplantation into sublethally irradiated nonobese diabetic-scid/scid mice. Six weeks after the transplantation, in eight of eight animals receiving human HSC with the addition of SCF, a profound multilineage hematopoietic engraftment was detected, whereas in the control group receiving only HSC, none of eight animals engrafted. Our data provide the first in vivo evidence that stimulation with cytokines improves the homing ability of transplanted human hematopoietic progenitor cells.

Antigens, CD↗

PubMed2003

Antiangiogenetic therapy with pioglitazone, rofecoxib, and metronomic trofosfamide in patients with advanced malignant vascular tumors.

BACKGROUND: Systemic therapy options for patients with advanced angiosarcomas are limited, and their prognosis is poor. The idea of angiostatic therapy following the paradigm of metronomic dosed chemotherapeutics combined with proapoptotic biomodulators had not been considered previously in these patients. Therefore, in a pilot study, the efficacy of metronomically scheduled, low-dose trofosfamide in combination with the peroxisome proliferator-activated receptor gamma agonist, pioglitazone, and the selective cyclooxygenase-2 inhibitor, rofecoxib, was evaluated in patients with advanced vascular malignancies. METHODS: Six patients with advanced and pretreated but progressive, malignant vascular tumors (5 angiosarcomas and 1 hemangioendothelioma) received a combination of pioglitazone (45 mg per day orally) plus rofecoxib (25 mg per day orally) and, after 14 days, trofosfamide (3 x 50 mg per day orally). The therapy was administered continuously until progression was observed. If necessary, doses were modified according to side effects. RESULTS: Two patients responded with complete remission of disease, one patient responded with partial remission, and three patients achieved stabilization of disease (no change). The median progression-free survival was 7.7 months (range, 2-15 months). Side effects generally were mild (World Health Organization Grade 1-2). Hospitalization was not necessary. CONCLUSIONS: This new triple combination of low-dose metronomic trofosfamide, pioglitazone, and rofecoxib may represent a feasible new alternative in the palliative treatment of patients with advanced malignant vascular tumors.

Administration, Oral↗