Myeloid Cells

A large number of macrophages and haematopoietic progenitor cells accumulate in pre-metastatic lungs 1,2 in which chemoattractants, such as S100A8 and S100A9, are produced by distant primary tumours serving as metastatic soil 3 . The exact mechanism by which these chemoattractants elicit cell accumulation is not known. Here, we show that serum amyloid A (SAA) 3, which is induced in pre-metastatic lungs by S100A8 and S100A9, has a role in the accumulation of myeloid cells and acts as a positive-feedback regulator for chemoattractant secretion. We also show that in lung endothelial cells and macrophages, Toll-like receptor (TLR) 4 acts as a functional receptor for SAA3 in the pre-metastatic phase. In our study, SAA3 stimulated NF-κB signalling in a TLR4-dependent manner and facilitated metastasis. This inflammation-like state accelerated the migration of primary tumour cells to lung tissues, but this was suppressed by the inhibition of either TLR4 or SAA3. Thus, blocking SAA3-TLR4 function in the pre-metastatic phase could prove to be an effective strategy for the prevention of pulmonary metastasis.

The mouse 4T1 mammary carcinoma is a BALB/c-derived tumor that spontaneously metastasizes and induces immune suppression. Although >95% of wild type BALB/c mice die from metastatic 4T1 tumor even if the primary mammary tumor is surgically removed, >65% of BALB/c mice with a deleted Signal Transducer Activator of Transcription 6 (STAT6) gene survive post-surgery. STAT6-deficiency also confers enhanced immunity against spontaneously developing breast cancer since NeuT +/) mice that are STAT6deficient develop mammary tumors later and survive longer than NeuT +/) mice that are STAT6-competent. Rejection of metastastic disease and survival of STAT6deficient mice after removal of primary tumor involve three mechanisms: (1) The generation of M1 type macrophages that produce nitric oxide and are tumoricidal; (2) A decrease to normal in the elevated levels of myeloid suppressor cells that accumulate during primary tumor growth; and (3) CD8 + tumor-specific T lymphocytes. STAT6-deficient, but not wild type BALB/c, mice generate nitric oxide producing macrophages because they lack the STAT6 transcription factor which is necessary for signaling through the type 2 IL-4Ra complex, and which induces the production of arginase instead of nitric oxide. Keywords Tumor-induced immune suppression AE Immune surveillance AE M1 macrophages AE Metastatic breast cancer AE Cell-mediated tumor immunity Signal Transducer Activator of Transcription 6 deficient (STAT6-/-) mice have enhanced immunity to transplanted tumors This article is a symposium paper from the conference ''Tumor Escape and Its Determinants''

The sequence of a novel hemopoietic cytokine was discovered in a computational screen of genomic databases, and its homology to mouse thymic stromal lymphopoietin (TSLP) suggests that it is the human orthologue. Human TSLP is proposed to signal through a heterodimeric receptor complex that consists of a new member of the hemopoietin family termed human TSLP receptor and the IL-7R ␣-chain. Cells transfected with both receptor subunits proliferated in response to purified, recombinant human TSLP, with induced phosphorylation of Stat3 and Stat5. Human TSLPR and IL-7R␣ are principally coexpressed on monocytes and dendritic cell populations and to a much lesser extent on various lymphoid cells. In accord, we find that human TSLP functions mainly on myeloid cells; it induces the release of T cell-attracting chemokines from monocytes and, in particular, enhances the maturation of CD11c ؉ dendritic cells, as evidenced by the strong induction of the costimulatory molecules CD40 and CD80 and the enhanced capacity to elicit proliferation of naive T cells.

Obesity is increasingly being recognized as a risk factor for a number of benign and malignant gastrointestinal conditions. However, literature on the underlying pathophysiological mechanisms is sparse and ambiguous. There is compelling evidence that both overnutrition and undernutrition negatively interfere with the immune system. Overnutrition has been found to increase susceptibility to the development of inflammatory diseases, autoimmune diseases and cancer. In the regulation of immune and inflammatory processes, white adipose tissue plays a critical role, not only as an energy store but also as an important endocrine organ. The obese state is characterised by a low-grade systemic inflammation, mainly as a result of increased adipocytes as well as fat resident-and recruited-macrophage activity. In the past few years, various products of adipose tissue including adipokines and cytokines have been characterised and a number of path-ways linking adipose tissue metabolism with the immune system have been identified. Activation of the innate immune system plays a major role in hepatic steatosis. Non-alcoholic fatty liver disease includes a wide spectrum of diseases, from pure steatosis to non-alcoholic steatohepatitis in the absence of significant alcohol consumption. Although steatosis is considered a non-progressive disease, non-alcoholic steatohepatitis may deteriorate in advanced chronic liver diseases, cirrhosis, and hepatocellular carcinoma. An important parallel between obesityrelated pathology of adipose tissue and liver pertains to the emerging role of macrophages, and growing evidence suggests that Kupffer cells critically contribute to progression of non-alcoholic fatty liver disease. Moreover, a close link between specific immune activation and atherosclerosis has been well established, suggesting that fat can directly trigger immune responses. This review discusses the role of fat as "a matter of disturbance for the immune system" with a focus on hepatic steatosis.

The use of flow cytometric enumeration of blasts in bone marrow aspirates has been of limited value in situations where blood contamination of the specimen is present. Assessment of sequential pulls of bone marrow aspirates from the same patient show decreasing proportions of blasts that are detected in later specimens. To address this problem, the intensity of CD16 on maturing neutrophils was compared for bone marrow biopsies, peripheral blood, and bone marrow aspirates. A comparison between bone marrow biopsy and aspirate specimens from the same individuals showed similar proportions of neutrophils with mature phenotype in most, but not all pairs. Other cell populations (total mature lymphocytes, monocytes, neutrophils, and blasts) were also similar between the two specimen types, with one exception of a patient with myelodysplasia, exhibiting a unique blast population in the biopsy that was not evident in the aspirate. The proportion of mature myeloid cells expressing a mature neutrophil phenotype (high levels of CD16) was found to be 17% (± 6.7, n = 47) in trephine marrow biopsy specimens. In contrast, marrow aspirates contained more of the mature neutrophil phenotype (38% ± 16, n = 33) with about 1/3 of the aspirates indistinguishable from biopsies. Using a simple formula to normalize the aspirate specimens to the average neutrophil composition of marrow biopsies, it was possible to correct for the dilutional effect of added blood to both normal bone marrow aspirates and aspirates with elevated blast counts. These results suggest three alternative means of circumventing the problem of blood dilution of marrow aspirate specimens. (1) Blast counts by flow cytometry can be obtained from disaggregated biopsy specimens. (2) A bone marrow aspirate can be assessed for the proportion of mature neutrophils present and only those with low proportions (<30%) of phenotypic mature neutrophils are considered adequate for blast counting. (3) The aspirates with high proportions of mature neutrophils may be normalized based on the proportion of dim CD16 maturing myeloid cells to a level observed in bone marrow biopsies (based on an average mature neutrophil composition). Such an approach for identifying the amount of hemodilution in each specimen may enhance the utility of flow cytometry in enumeration of blasts in bone marrow, especially in cases where myeloblast count is crucial for prognosis, such as myelodysplastic syndromes (MDS). q

Senior author: Gosse J. Adema (NKT) cells can acquire the ability to convert immunosuppressive MDSCs into immunity-promoting antigen-presenting cells. Here we will review the cross-talk between MDSCs and other immune cells, focusing on Treg cells and NKT cells. We will consider its impact on basic and applied cancer research and discuss how targeting MDSCs may pave the way for future immunocombination therapies.

Stroke induces a systemic response that involves rapid activation of inflammatory cascades, followed later by immunodepression. Experimental stroke-induced responses in the bone marrow, which is the primary source of circulating monocytes and granulocytes, have not been investigated previously. We show that cerebral ischaemia induced early (4 hours) release of CXCR2-positive granulocytes from the bone marrow, which was associated with rapid systemic upregulation of CXCL1 (a ligand for CXCR2) and granulocyte-colony-stimulating factor, a key cytokine involved in the mobilisation of bone marrow leukocytes. This process involves rapid activation of nuclear factor-jB and p38 mitogen-activated protein kinase in bone marrow myeloid cells. T-cell numbers in the bone marrow increased after stroke, and bone marrow cells did not show suppressed cytokine response to bacterial endotoxin stimulation in vitro. Stroke-induced laterality observed in the brain stem and in the bone marrow indicates direct involvement of the autonomic nervous system in stroke-induced cell mobilisation. We also show that systemic inflammatory changes and leukocyte responses in the bone marrow are profoundly affected by both anaesthetic and surgical stress. We conclude that stroke influences leukocyte responses in the bone marrow through multiple mechanisms and suggest that preclinical studies should take into consideration the effect of surgical manipulation in experimental models of stroke.

Cells from the mononuclear phagocyte system (MPS) act as systemic and local amplifiers that contribute to the progression of chronic inflammatory disorders. Transforming growth factor-␤-activated kinase 1 (TAK1) is a pivotal upstream mitogen-activated protein kinase-kinasekinase acting as a mediator of cytokine expression. It remains critical to determine in vivo the implication of TAK1 in controlling the innate immune system. Here, we describe a vehicle tailored to selectively deliver siRNAs into MPS cells after intravenous administration, and validate in vivo the potential of the RNAimediated TAK1 knock down for immunomodulation. In a mouse model of immunemediated inflammatory disorder, we show that anti-TAK1 siRNA lipoplexes efficiently alleviate inflammation, severely impair the downstream c-Jun N-terminal kinase and nuclear factor-B signaling pathways, and decrease the expression of proinflammatory mediators. Impor-tantly, the systemic TAK1 gene silencing decreases the frequency of Th1 and Th17 cells, both mediating autoimmunity in experimental arthritis, demonstrating the immunomodulatory potential of TAK1.

Increased HIV-1 production by CD4 ؉ T lymphocytes was paralleled with their specific depletion in the peripheral blood of the JR-CSF/hu-cycT1 mice, which increased over time. In addition, increased HIV-1 transgene expression due to human cyclin T1 expression was associated with increased lipopolysaccharide-stimulated monocyte chemoattractant protein 1 production by JR-CSF mouse monocytes/ macrophages in vitro. Therefore, the JR-CSF/hu-cycT1 mice should provide an improved mouse system for investigating the pathogenesis of various aspects of HIV-1-mediated disease and the efficacies of therapeutic interventions.

Inflammatory cell infiltration of tumors contributes either positively or negatively to tumor invasion, growth, metastasis, and patient outcomes, creating a Dr. Jekyll or Mr. Hyde conundrum when examining mechanisms of action. This is due to tumor heterogeneity and the diversity of the inflammatory cell phenotypes that infiltrate primary and metastatic lesions. Tumor infiltration by macrophages is generally associated with neoangiogenesis and negative outcomes, whereas dendritic cell (DC) infiltration is typically associated with a positive clinical outcome in association with their ability to present tumor antigens (Ags) and induce Ag-specific T cell responses. Myeloid-derived suppressor cells (MDSCs) also infiltrate tumors, inhibiting immune responses and facilitating tumor growth and metastasis. In contrast, T cell infiltration of tumors provides a positive prognostic surrogate, although subset analyses suggest that not all infiltrating T cells predict a positive outcome. In general, infiltration by CD8 + T cells predicts a positive outcome, while CD4 + cells predict a negative outcome. Therefore, the analysis of cellular phenotypes and potentially spatial distribution of infiltrating cells are critical for an accurate assessment of outcome. Similarly, cellular infiltration of metastatic foci is also a critical parameter for inducing therapeutic responses, as well as establishing tumor dormancy. Current strategies for cellular, gene, and molecular therapies are focused on the manipulation of infiltrating cellular populations. Within this review, we discuss the role of tumor infiltrating, myeloid-monocytic cells, and T lymphocytes, as well as their potential for tumor control, immunosuppression, and facilitation of metastasis.

Monocytes have been categorized in three main subpopulations based on CD14 and CD16 surface expression. Classical monocytes express the CD14(++)CD16(-) CCR2(+) phenotype and migrate to inflammatory sites by quickly responding to CCL2 signaling. Here, we identified and characterized the expansion of a novel monocyte subset during HIV and SIV infection, which were undistinguishable from classical monocytes, based on CD14 and CD16 expression, but expressed significantly lower surface CCR2. Transcriptome analysis of sorted cells demonstrated that the CCR2(low/neg) cells are a distinct subpopulation and express lower levels of inflammatory cytokines and activation markers than their CCR2(high) counterparts. They exhibited impaired phagocytosis and greatly diminished chemotaxis in response to CCL2 and CCL7. In addition, these monocytes are refractory to SIV infection and suppress CD8(+) T cell proliferation in vitro. These cells express higher levels of STAT3 and NOS2, suggesting a phenot...

In some settings increasing high density lipoprotein (HDL) levels has been associated with a reduction in experimental atherosclerosis. This has been most clearly seen in apolipoprotein A-I (apoA-I) transgenic mice or in animals infused with HDL or its apolipoproteins. A major mechanism by which these treatments are thought to delay progression or cause regression of atherosclerosis is by promoting efflux of cholesterol from macrophage foam cells. In addition, HDL has been described as having anti-inflammatory and other beneficial effects. Some recent research has linked anti-inflammatory effects to cholesterol efflux pathways but likely multiple mechanisms are involved. Macrophage cholesterol efflux may have a role in facilitating emigration of macrophages from lesions during regression. While macrophages can mediate cholesterol efflux by several pathways, studies in knockout mice or cells point to the importance of active efflux mediated by ATP binding cassette transporter (ABC) A1 and G1. In addition to traditional roles in macrophages, these transporters have been implicated in the control of hematopoietic stem cell proliferation, monocytosis and neutrophilia, as well as activation of monocytes and neutrophils. Thus, HDL and cholesterol efflux pathways may have important antiatherogenic effects at all stages of the myeloid cell/monocyte/dendritic cell/macrophage lifecycle.

| The use of various transgenic mouse models and analysis of human tumour biopsies has shown that bone marrow-derived myeloid cells, such as macrophages, neutrophils, eosinophils, mast cells and dendritic cells, have an important role in regulating the formation and maintenance of blood vessels in tumours. In this Review the evidence for each of these cell types driving tumour angiogenesis is outlined, along with the mechanisms regulating their recruitment and activation by the tumour microenvironment. We also discuss the therapeutic implications of recent findings that specific myeloid cell populations modulate the responses of tumours to agents such as chemotherapy and some anti-angiogenic therapies.

A major barrier for cancer immunotherapy is the presence of suppressive cell populations in patients with cancer, such as myeloid-derived suppressor cells (MDSC) and tumor-associated macrophages (TAM), which contribute to the immunosuppressive microenvironment that promotes tumor growth and metastasis. Tasquinimod is a novel antitumor agent that is currently at an advanced stage of clinical development for treatment of castration-resistant prostate cancer. A target of tasquinimod is the inflammatory protein S100A9, which has been demonstrated to affect the accumulation and function of tumor-suppressive myeloid cells. Here, we report that tasquinimod provided a significant enhancement to the antitumor effects of two different immunotherapeutics in mouse models of cancer: a tumor vaccine (SurVaxM) for prostate cancer and a tumor-targeted superantigen (TTS) for melanoma. In the combination strategies, tasquinimod inhibited distinct MDSC populations and TAMs of the M2-polarized phenotyp...

Objective. The protooncogene c-Myc plays an important role in the control of cell proliferation, apoptosis, and differentiation, and its aberrant expression is frequently seen in multiple human cancers, including acute myeloid leukemia (AML). As c-Myc heterodimerizes with Max to transactivate downstream target genes in leukemogenesis. Inhibition of the c-Myc/ Max heterodimerization by the recently identified small-molecule compound, 10058-F4, might be a novel antileukemic strategy. Materials and Methods. HL-60, U937, and NB4 cells and primary AML cells were used to examine the effects of 10058-F4 on apoptosis and myeloid differentiation. Results. We showed that10058-F4 arrested AML cells at G 0 /G 1 phase, downregulated c-Myc expression and upregulated CDK inhibitors, p21 and p27. Meanwhile, 10058-F4 induced apoptosis through activation of mitochondrial pathway shown by downregulation of Bcl-2, upregulation of Bax, release of cytoplasmic cytochrome C, and cleavage of caspase 3, 7, and 9. Furthermore, 10058-F4 also induced myeloid differentiation, possibly through activation of multiple transcription factors. Similarly, 10058-F4-induced apoptosis and differentiation could also be observed in primary AML cells. Conclusion. Our study has shown that inhibition of c-Myc/Max dimerization with smallmolecule inhibitors affects multiple cellular activities in AML cells and represents a potential antileukemic approach. Ó

Background: The antitumor immune response in patients with B-cell NHL plays an important role in determining clinical outcome. We have previously shown that an increased absolute monocyte count in the peripheral blood of lymphoma patients is associated with a poor prognosis. Furthermore, we have identified a population of CD14+HLADRlow monocytes in NHL patients that are immunosuppressive. The goal of this study was to further define the phenotype of suppressive monocytes in lymphoma patients and to identify the conditions that promote their expansion. Methods: Peripheral blood specimens were obtained from patients with newly diagnosed, untreated B-cell NHL (n=20) and 20 matched controls; and the phenotype of the monocyte fraction was analyzed by 10-color flow cytometry. Monocytes from an additional 15 healthy controls were polarized to express a phenotype similar to that seen in lymphoma patients. Serum from 361 lymphoma patients and 337 matched controls were used to confirm differences in cytokine production. Results: The number of monocytes in the peripheral blood of NHL patients was increased compared to controls (p=0.024), due in part to an increase in CD14+CD16- HLADRlow monocytes that also expressed CD32 and CD163, and were positive for IL-10. Increased levels of IL-10 were found in the serum of lymphoma patients (median: 27.5ng/ml; 14.5-53.4) when compared to controls (median: 16.4ng/ml; 8.8-26, p=0.001). Monocytes from healthy donors were then polarized with GMCSF+/-LPS and IFNg or MCSF+/-IL-4 to attempt to mimic the phenotype seen in lymphoma patients. Monocytes treated with MCSF+/-IL-4 developed a similar phenotype to monocytes from lymphoma patients and were CD14+CD16-IL10+, however they remained HLADR+. When MCSF- or GMCSF-treated monocytes were co-cultured with T-cells, MCSF-treated monocytes suppressed T-cell cytokine secretion and induced FoxP3 expression. Conclusions: CD14+CD16-HLADRlow monocytes in NHL patients express immunosuppressive ligands, secrete IL-10 and suppress T-cell function. They may represent a therapeutic target in lymphoma patients.

The aim of this study was to evaluate lineage-specific chimerism reconstitution after reduced-intensity allogeneic stem cell transplantation (RIST) using a combination of fludarabine (30 mg/m2 for 6 days) and busulfan (4 mg/kg for 2 days). We prospectively enrolled 8 consecutive patients with hematologic malignancies who were not candidates for conventional transplantation because of either high age or organ dysfunction. Host-donor chimerism was evaluated using polymerase chain reaction-based amplification of a polymorphic short tandem repeat region. All of our patients achieved engraftment within a median of 11 days after transplantation. On day 30, full donor myeloid cell chimerism (&gt;90%) was achieved in 7 patients whereas full donor T-cell chimerism was achieved in only one patient. Thus, in contrast to other reported results, full donor chimerism was achieved earlier in the myeloid lineage than the T-cell lineage. On day 60, however, T-cell chimerism caught up with myeloid ch...

M. tuberculosis and M. leprae are considered to be prototypical intracellular pathogens that have evolved strategies to enable growth in the intracellular phagosomes. In contrast, we show that lysosomes rapidly fuse with the virulent M. tuberculosis-and M. leprae-containing ...

Advances in cell-fate mapping have revealed the complexity in phenotype, ontogeny and tissue distribution of the mammalian myeloid system. To capture this phenotypic diversity, we developed a 38-antibody panel for mass cytometry and used dimensionality reduction with machine learning-aided cluster analysis to build a composite of murine (mouse) myeloid cells in the steady state across lymphoid and nonlymphoid tissues. In addition to identifying all previously described myeloid populations, higher-order analysis allowed objective delineation of otherwise ambiguous subsets, including monocyte-macrophage intermediates and an array of granulocyte variants. Using mice that cannot sense granulocyte macrophage-colony stimulating factor GM-CSF (Csf2rb −/− ), which have discrete alterations in myeloid development, we confirmed differences in barrier tissue dendritic cells, lung macrophages and eosinophils. The methodology further identified variations in the monocyte and innate lymphoid cell compartment that were unexpected, which confirmed that this approach is a powerful tool for unambiguous and unbiased characterization of the myeloid system.

The aim of this study is to validate the clinical utility of the flow cytometric scoring system (FCSS), quantifying phenotypic aberrancies in the myelomonocytic lineages, in the diagnosis and prognosis for conventionally treated myelodysplastic syndromes (MDS) patients. The bone marrow samples from 56 consecutive newly diagnosed MDS patients were characterized by the FCSS and compared with findings in 27 non-MDS cytopenic patients. The FCSS scores were significantly higher in patients with MDS than those in the non-MDS control. A flow score of 2 or more allowed for a specificity of 100% with 75% sensitivity in distinguishing these two groups. The FCSS scores correlated directly with validated prognostic systems including WHO classification, International Prognostic Scoring System (IPSS), WHO-adjusted prognostic scoring system (WPSS) and transfusion dependency. The median survival of conventionally treated MDS patients was directly related to FCSS group; severe: 6 months; moderate: 19 months and normal/mild: not reached. The multivariate analyses suggested the FCSS risk categories were an independent prognostic factor after adjustment for sex, age (above or below 70 years), IPSS or WPSS risk categories. These results confirm that quantifying aberrancies in the myelomonocytic lineage by FCSS is useful in MDS diagnosis and extends the prognostic utility for conventionally treated/untreated patients, especially among patients classified within the refractory cytopenia with multilineage dysplasia (RCMD) subgroup.

The immature myeloid information (IMI) provided by the Sysmex XE 2100 hematology analyzer has demonstrated that it is possible to differentiate granulocytes of immature cells in daily practice. A specifi c reagent lyses mature white blood cells, allowing that immature myeloid cells remain intact and consequently detectable. It is known that lymphoblasts cannot be detected in this channel. This channel does not entail additional costs, since it is provided by the traditional hematology analyzers used in blood tests and is widely useful in differentiating cell lines. This study has aimed to assess the consonance between IMI results and subtypes of acute leukemias and other hematologic malignancies in order to use it as screening test in the defi nition of cell lineage. A total of 141 cases of hematologic malignancies have been evaluated. Results of the IMI channel were compared using the Sudan Black cytochemical and fl ow cytometry. The Cohen's Kappa coeffi cient of agreement between IMI and fl ow cytometry results was 0.8%. IMI had sensibility and specifi city levels of 90.7% and 90.8%, respectively; VP: 68 (91.9%); FP: 6 (8.1%); VN: 59 (89.4%) and FN: 7 (10.6%); PPV 91.9% and NPV 89.4%. The Sysmex XE 2100 analyzer showed a good analytical performance for the detection of immature myeloid cells. These results indicate that the IMI channel has sensitivity and specifi city levels, consistent with previous studies. Given this situation, one may conclude that IMI was able to be used as a screening test to complement cytochemistry for identify blasts of myeloid lineage.

Clinical bone marrow specimens submitted to the University of Minnesota's Veterinary Teaching Hospital Cytology Service over a 3-year period were evaluated for the presence of myelodysplastic features. Of 220 bone marrow specimens examined, 30 contained dysplastic features. Twenty-seven of these dogs were evaluated further. Twelve were categorized as primary myelodysplastic syndromes, and 15 were categorized as secondary myelodysplastic syndromes. Of the primary myelodysplastic syndromes, 4 were subcategorized as refractory anemia and 8 were categorized as myelodysplasia. Primary refractory anemia was characterized by nonregenerative anemia without leukopenia or thrombocytopenia and with prolonged survival. Primary myelodysplasia was characterized by pancytopenia, greater than 5% myeloblasts in bone marrow, dysplastic features in all bone marrow cell lines, and short survival time. Results of this study indicate that differentiating primary refractory anemia from primary myelodysplasia has both therapeutic and prognostic significance. Dogs with primary refractory anemia tend to have prolonged survival and respond to erythropoietin treatment, whereas dogs with primary myelodysplasia have short survival and do not respond to standard treatments.

Bladder cancer is associated with enhanced inflammation and characterized by deregulated prostanoid metabolism. Here we examined prostaglandin E 2 (PGE 2 ) metabolism and myeloid cell subsets that infiltrate tumor tissue using two xenograft models of human bladder cancer. Human bladder tumor xenografts implanted into athymic nude mice become highly infiltrated with host CD11b myeloid cells of bone marrow origin. Fast growing SW780 bladder tumor xenografts were infiltrated with heterogeneous CD11b myeloid cell subsets including tumor-associated macrophages and myeloid-derived suppressor cells. In contrast, majority of myeloid cells in tumor tissue from slow growing bladder cancer Urothel 11 displayed more immature, homogenous phenotype and comprised mostly MHC II class-negative myeloid-derived suppressor cells. We demonstrate that human bladder tumors secrete substantial amounts of PGE 2 . Normal bone marrow myeloid cell progenitors cultured in the presence of a bladder tumor-conditioned medium, which is enriched for PGE 2 , failed to differentiate into mature APCs and acquired phenotype of the myeloid-derived suppressor cells or inflammatory macrophages with up-regulated chemokine receptor CXCR4. Collectively our data demonstrate that enhanced cancer-related inflammation and deregulated PGE 2 metabolism in tumor microenvironment promote immunosuppressive pro-tumoral phenotype of myeloid cells in bladder cancer. These data also suggest that not only local tumor microenvironment but other factors such as stage of cancer disease and pace of tumor growth could markedly influence the phenotype, differentiation and immune function of myeloid cells in tumor tissue.

Myeloid-derived suppressor cells (MDSCs) increase during tumor growth and following cytoreductive therapy resulting in immune dysfunction and tumor escape from host control. We report organ-and tumor-specific expansion of MDSCs, differences in their molecular and membrane phenotypes and T-cell suppressive activity. A significant increase in MDSCs was observed within the spleen, peripheral blood (PB), bone marrow (BM), lungs, and livers of mice bearing orthotopic 4T1, but not CI66 mammary tumors. The PB of 4T1 TB mice had the highest frequency of MDSCs (78.6 ± 2.1%). Similarly, the non-parenchymal cells (NPCs) in the tumor tissue, livers and lungs of 4T1 tumor-bearing (TB) mice had an increased MDSCs frequency. Studies into Gr-1 and Ly-6C staining of MDSCs revealed significant increases in CD11b + Gr-1 dull Ly-6C high and CD11b + Gr-1 bright Ly-6C low subsets. The frequency of MDSCs inversely correlated with the CD3 + T-cell frequency in the spleen, and blood of 4T1 TB mice and was associated with a significant decrease in splenic and NPCs IFN-γ and IL-12 transcript levels, as well as significantly increased levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), stem cell factor (SCF), granulocyte colony-stimulating factor (G-CSF), interleukin-10 (IL-10), interleukin-13 (IL-13), arginase-1 (ARG-1), nitric oxide synthase (NOS-2), vascular endothelial growth factor-A (VEGF-A) transcripts. In summary, MDSCs are significantly increased not only in lymphoid organs, but also in parenchymal organs including lungs and livers of TB mice, where they may facilitate metastasis to these organ sites.

Following our observation that erythrosine B (FD&C Red No. 3) is a relatively potent inhibitor of the TNF-R-TNFa and CD40-CD154 protein-protein interactions, we investigated whether this inhibitory activity extends to any other protein-protein interactions (PPI) as well as whether any other approved food colors possess such inhibitory activity. We found erythrosine, a poly-iodinated xanthene dye, to be a nonspecific promiscuous inhibitor of a number of PPIs within the tumor necrosis factor superfamily (TNF-R-TNFa, CD40-CD154, BAFF-R-BAFF, RANK-RANKL, OX40-OX40L, 4-1BB-4-1BBL) as well as outside of it (EGF-R-EGF) with a remarkably consistent median inhibitory concentration (IC 50 ) in the 2-20 mM (approximately 2-20 mg/L) range. In agreement with this, erythrosine also showed cellular effects including clear cytotoxic effects around this concentration range (IC 50 % 50 mM). Among the seven FDAapproved food colorants, only erythrosine showed consistent PPI inhibitory activity in the sub-100 mM range, which might also explain (at least partially) why it also has the lowest approved acceptable daily intake (ADI) (0.1 mg/kg body weight/day). Among a number of xanthene structural analogs of erythrosine tested for activity, rose Bengal, a food colorant approved in Japan, showed similar, maybe even more pronounced, promiscuous inhibitory activity, whereas fluorescein was inactive and gallein, phloxine, and eosin were somewhat active in some of the assays.

The role of angiogenesis in the growth of lymphomas and survival of patients with leukemias and other hematological malignancies has become evident since 1994. Angiogenic factors, such as vascular endothelial growth factor and its receptors together with other tumor microenvironment components, including myelo-monocytic cell, mast cells, endothelial progenitor cells, and circulating endothelial cells, have been shown to be important in the progression and maintenance of lymphoproliferative disorders. In this review article, we present an overview of the literature focusing on the relationship between angiogenesis and disease progression and the recent advantages in the antiangiogenic treatment in human non-Hodgkin lymphomas.

CITATIONS 43 READS 22 7 authors, including: Some of the authors of this publication are also working on these related projects: Investigating circulating tumor cells in general and cancer stem cells in particular in solid and hematological tumors and how it correlate to the immunological and clinical performance View project

Flow cytometry is nowadays the first-line method for immunophenotypic identification of blast cells but is not so usual in limited-resources countries. We have investigated on the usefulness of this tool in Abidjan, Côte d&#39;Ivoire. Bone marrow sample from 13 patients with acute leukemia identified by cytology and cytochemical analysis was immunophenotyped by using monoclonal antibodies directed to: T lymphoid cells (CD3, CD5, CD7); B lymphoid cells (CD10, CD19, CD20, CD22, HLA-DR) and myeloid cells (CD13, CD33). Immunophenotyping allowed us to confirm the diagnosis of 6 de novo acute leukemias (2 acute myeloid leukaemias, 4 acute lymphoid leukemias) and 7 acute leukaemias resulting from chronic myeloid leukaemias. Immunophenotyping also characterizes the atypical/aberrant lineage essential for the prognosis: 2 biphenotypic acute leukemias (myeloid/lymphoid T) were identified. Our results suggest that flow cytometry may be a useful additional tool to identify the specific leukemic...

Cell-cell interactions mediated by cell surface receptor-ligand pairs in the immune system are often of low affinity and transient in nature. To begin to study these weak interactions, it is desirable to devise a generally applicable method for screening for and enriching cells expressing low-affinity ligands for specific cell surface receptors. We describe here an experimental strategy that uses a multivalent form of protein as a probe to identify and characterize cognate ligand(s) of myeloid cell surface receptors. Recombinant fusion proteins containing the receptor protein fragment of interest fused to a truncated Fc domain and a unique biotinylation signal are produced, biotinylated, and coupled to (strep)avidin-coated fluorescent or paramagnetic microspheres. These multivalent microparticle probes are then used to screen or capture cells expressing the cognate cellular ligand(s).