Monocyte-derived CXCL7 peptides in the marrow microenvironment

Integrative proteome analysis of bone marrow interstitial fluid and serum reveals candidate signature for acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive form of blood cancer and clinically highly heterogeneous characterized by the accumulation of clonally proliferative immature precursors of myeloid lineage leading to bone marrow failure. Although, the current diagnostic methods for AML consist of cytogenetic and molecular assessment, there is a need for new markers that can serve as useful candidates in diagnosis, prognosis and understanding the pathophysiology of the disease. This study involves the investigation of alterations in the bone marrow interstitial fluid and serum proteome of AML patients compared to controls using label-free quantitative proteomic approach. A total of 201 differentially abundant proteins were identified in AML BMIF, while in the case of serum 123 differentially abundant proteins were identified. The bioinformatics analysis performed using IPA revealed several altered pathways including FAK signalling, IL-12 signalling and production of macrophages etc. Verification experiments were performed in a fresh independent cohort of samples using MRM assays led to the identification of a panel of three proteins viz., PPBP, APOH, ENOA which were further validated in a new cohort of serum samples by ELISA. The three-protein panel could be helpful in the diagnosis, prognosis and understanding of the pathophysiology of AML in the future. BIOLOGICAL SIGNIFICANCE: Acute Myeloid Leukemia (AML) is a type haematological malignancy which constitute one third of total leukemias and it is the most common acute leukemia in adults. In the current clinical practice, the evaluation of diagnosis and progression of AML is largely based on morphologic, immunophenotypic, cytogenetic and molecular assessment. There is a need for new markers/signatures which can serve as useful candidates in diagnosis and prognosis. The present study aims to identify and validate candidate biosignature for AML which can be useful in diagnosis, prognosis and understand the pathophysiology of the disease. Here, we identified 201 altered proteins in AML BMIF and 123 in serum. Among these altered proteins, a set of three proteins viz., pro-platelet basic protein (CXCL7), enolase 1 (ENO1) and beta-2-glycoprotein 1 (APOH) were significantly increased in AML BMIF and serum suggest that this panel of proteins could help in future AML disease management and thereby improving the survival expectancy of AML patients.

Multifaceted Roles of Chemokine C-X-C Motif Ligand 7 in Inflammatory Diseases and Cancer

Over recent years, C-X-C motif ligand 7 (CXCL7) has received widespread attention as a chemokine involved in inflammatory responses. Abnormal production of the chemokine CXCL7 has been identified in different inflammatory diseases; nevertheless, the exact role of CXCL7 in the pathogenesis of inflammatory diseases is not fully understood. Persistent infection or chronic inflammation can induce tumorigenesis and progression. Previous studies have shown that the pro-inflammatory chemokine CXCL7 is also expressed by malignant tumor cells and that binding of CXCL7 to its cognate receptors C-X-C chemokine receptor 1 (CXCR1) and C-X-C chemokine receptor 2 (CXCR2) can influence tumor biological behavior (proliferation, invasion, metastasis, and tumor angiogenesis) in an autocrine and paracrine manner. CXCL7 and its receptor CXCR1/CXCR2, which are aberrantly expressed in tumors, may represent new targets for clinical tumor immunotherapy.

The Role of CXC Chemokines in Cardiovascular Diseases

Cardiovascular disease (CVD) is a class of diseases with high disability and mortality rates. In the elderly population, the incidence of cardiovascular disease is increasing annually. Between 1990 and 2016, the age-standardised prevalence of CVD in China significantly increased by 14.7%, and the number of cardiovascular disease deaths increased from 2.51 million to 3.97 million. Much research has indicated that cardiovascular disease is closely related to inflammation, immunity, injury and repair. Chemokines, which induce directed chemotaxis of reactive cells, are divided into four subfamilies: CXC, CC, CX3C, and XC. As cytokines, CXC chemokines are similarly involved in inflammation, immunity, injury, and repair and play a role in many cardiovascular diseases, such as atherosclerosis, myocardial infarction, cardiac ischaemia-reperfusion injury, hypertension, aortic aneurysm, cardiac fibrosis, postcardiac rejection, and atrial fibrillation. Here, we explored the relationship between the chemokine CXC subset and cardiovascular disease and its mechanism of action with the goal of further understanding the onset of cardiovascular disease.

Identification and validation of inferior prognostic genes associated with immune signatures and chemotherapy outcome in acute myeloid leukemia

Acute myeloid leukemia (AML) is a group of heterogeneous hematological malignancies. We identified key genes as ITGAM and lncRNA ITGB2-AS1 through different bioinformatics tools. Furthermore, qPCR was performed to verify the expression level of essential genes in clinical samples. Retrospective research on 179 AML cases was used to investigate the relationship between the expression of ITGAM and the characteristics of AML. The critical gene relationship with immune infiltration in AML was estimated. The clinical validation and prognostic investigation showed that ITGAM, PPBP, and ITGB2-AS1 are highly expressed in AML (P < 0.001) and significantly associated with the overall survival in AML. Moreover, the retrospective research on 179 clinical cases showed that positive expression of ITGAM is substantially related to AML classification (P < 0.001), higher count of white blood cells (P < 0.01), and poor chemotherapy outcome (P < 0.05). Furthermore, based on grouping ITGAM as the high and low expression in TCGA-LAML profile, we found that genes in the highly expressed ITGAM group are mainly involved in immune infiltration and inflammation-related signaling pathways. Finally, we discovered that the expression level of ITGAM and lncRNA ITGB2-AS1 are not just closely related to the immune score and stromal score (P < 0.001) but also significantly positively correlated with various Immune signatures in AML (P < 0.001), indicating the association of these genes with immunosuppression in AML. The prediction of candidate drugs indicated that certain immunosuppressive drugs have potential therapeutic effects for AML. The critical genes could be used as potential biomarkers to evaluate the survival and prognosis of AML.

Analysis of deficiency of adenosine deaminase 2 pathogenesis based on single-cell RNA sequencing of monocytes

Deficiency of adenosine deaminase 2 (DADA2) is a rare autosomal recessive disease caused by loss-of-function variants in the ADA2 gene. DADA2 typically presents in childhood and is characterized by vasculopathy, stroke, inflammation, immunodeficiency, as well as hematologic manifestations. ADA2 protein is predominantly present in stimulated monocytes, dendritic cells, and macrophages. To elucidate molecular mechanisms in DADA2, CD14⁺ monocytes from 14 patients and 6 healthy donors were analyzed using single-cell RNA sequencing (scRNA-seq). Monocytes were purified by positive selection based on CD14 expression. Subpopulations were imputed from their transcriptomes. Based on scRNA-seq, monocytes could be classified as classical, intermediate, and nonclassical. Further, we used gene pathway analytics to interpret patterns of up- and down-regulated gene transcription. In DADA2, the frequency of nonclassical monocytes was higher compared with that of healthy donors, and M1 macrophage markers were up-regulated in patients. By comparing gene expression of each monocyte subtype between patients and healthy donors, we identified upregulated immune response pathways, including IFNα/β and IFNγ signaling, in all monocyte subtypes. Distinctively, the TNFR2 noncanonical NF-κB pathway was up-regulated only in nonclassical monocytes. Patients' plasma showed increased IFNγ and TNFα levels. Our results suggest that elevated IFNγ activates cell signaling, leading to differentiation into M1 macrophages from monocytes and release of TNFα. Immune responses and more general response to stimuli pathways were up-regulated in DADA2 monocytes, and protein synthesis pathways were down-regulated, perhaps as stress responses. Our identification of novel aberrant immune pathways has implications for therapeutic approaches in DADA2 (registered at clinicaltrials.gov NCT00071045).

Upregulation of Chemokines in the Paraventricular Nucleus of the Hypothalamus in Rats with Stress-Induced Hypertension

Background

The neuroinflammation of paraventricular nucleus (PVN) of the hypothalamus has been implicated in the development of hypertension. The promoted invasion of peripheral immune cells into PVN may be attributed to the upregulation of chemokines, then exacerbating neuroinflammation. We studied the expressions of chemokines, activation of microglial cells, and inflammatory mediators in PVN of rats with stress-induced hypertension (SIH).

Material/Methods

SIH was induced by electrical foot shock combined with noise for 2 h twice a day, at an interval of 4 h for 14 consecutive days. At the end of the 14th day, fresh PVN tissues were collected to measure the expressions of chemokines using the RayBiotech antibody array.

Results

We are the first to report that the expression of CXCL7 was extremely high in PVN of control rats, and was significantly lower in SIH rats. The expressions of CCL2 and CX3CL1 in PVN of SIH rats significantly exceeded those of control rats. The numbers of CX3CR1 (receptor of CX3CL1)-immunostained cells and oxycocin-42 (OX-42, marker of microglia)-positive cells increased in PVN of the SIH rats. The stress enhanced the protein expressions of proinflammatory cytokines IL-6 and IL-17 and reduced those of anti-inflammatory cytokines TGF-β and IL-10 in PVN.

Conclusions

In PVN of SIH rats, chronic stress induced neuroinflammation characterized by the activated microglia and upregulated proinflammatory cytokines. Expressions of chemokines CXCL7, CX3CL1, and CCL2 were altered. The causal link of chemokines to PVN neuroinflammation and hypertension remain to be determined.

Investigation of the Underlying Genes and Mechanism of Macrophage-Enriched Ruptured Atherosclerotic Plaques Using Bioinformatics Method

Aim: The study aimed to identify the underlying differentially expressed genes (DEGs) and mechanism of macrophage-enriched rupture atherosclerotic plaque using bioinformatics methods.

Methods: GSE41571, which includes six stable samples and five ruptured atherosclerotic samples, was downloaded from the GEO database. After preprocessing, DEGs between ruptured and stable atherosclerotic samples were identified using LIMMA. Gene Ontology biological process (GO_BP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DEGs were performed using the Database for Annotation, Visualization, and Integration Discovery (DAVID) online tool. Based on the STRING database, protein-protein interactions (PPIs) network among DEGs were constructed. Regulatory relationships between miRNAs/transcriptional factors (TFs) and target genes were predicted using Enrichr, and regulatory networks were visualized using Cytoscape.

Results: A total of 268 DEGs (64 up-regulated and 204 down-regulated DEGs) were identified between ruptured and stable samples. In the PPI network, collagen type III alpha 1 chain (COL3A1), collagen type I alpha 2 chain (COL1A2), and asporin (ASPN) were more than 15 interaction degrees. In the miRNA-target network, miR21 was highlighted with highest degrees and ASPN could be targeted by miR21. Functional enrichment analysis showed that COL3A1 and COL1A2 were significantly enriched in extracellular matrix organization and cell adhesion GO_BP terms. Pre-platelet basic protein (PPBP) was the most significantly up-regulated gene in ruptured atherosclerotic samples and enriched in immune response and inflammatory response GO_BP terms.

Conclusions: Down-regulated COL3A1, COL1A2 and ASPN, and up-regulated PPBP might perform critical promotional roles in atherosclerotic plaque rupture. Furthermore, miR21 might be potential target to prevent atherosclerotic rupture.

Engineering a multicellular vascular niche to model hematopoietic cell trafficking

BACKGROUND

The marrow microenvironment and vasculature plays a critical role in regulating hematopoietic cell recruitment, residence, and maturation. Extensive in vitro and in vivo studies have aimed to understand the marrow cell types that contribute to hematopoiesis and the stem cell environment. Nonetheless, in vitro models are limited by a lack of complex multicellular interactions, and cellular interactions are not easily manipulated in vivo. Here, we develop an engineered human vascular marrow niche to examine the three-dimensional cell interactions that direct hematopoietic cell trafficking.

METHODS

Using soft lithography and injection molding techniques, fully endothelialized vascular networks were fabricated in type I collagen matrix, and co-cultured under flow with embedded marrow fibroblast cells in the matrix. Marrow fibroblast (mesenchymal stem cells (MSCs), HS27a, or HS5) interactions with the endothelium were imaged via confocal microscopy and altered endothelial gene expression was analyzed with RT-PCR. Monocytes, hematopoietic progenitor cells, and leukemic cells were perfused through the network and their adhesion and migration was evaluated.

RESULTS

HS27a cells and MSCs interact directly with the vessel wall more than HS5 cells, which are not seen to make contact with the endothelial cells. In both HS27a and HS5 co-cultures, endothelial expression of junctional markers was reduced. HS27a co-cultures promote perfused monocytes to adhere and migrate within the vessel network. Hematopoietic progenitors rely on monocyte-fibroblast crosstalk to facilitate preferential recruitment within HS27a co-cultured vessels. In contrast, leukemic cells sense fibroblast differences and are recruited preferentially to HS5 and HS27a co-cultures, but monocytes are able to block this sensitivity.

CONCLUSIONS

We demonstrate the use of a microvascular platform that incorporates a tunable, multicellular composition to examine differences in hematopoietic cell trafficking. Differential recruitment of hematopoietic cell types to distinct fibroblast microenvironments highlights the complexity of cell-cell interactions within the marrow. This system allows for step-wise incorporation of cellular components to reveal the dynamic spatial and temporal interactions between endothelial cells, marrow-derived fibroblasts, and hematopoietic cells that comprise the marrow vascular niche. Furthermore, this platform has potential for use in testing therapeutics and personalized medicine in both normal and disease contexts.

Aging-associated oxidative stress inhibits liver progenitor cell activation in mice

Recent studies have discovered aging-associated changes of adult stem cells in various tissues and organs, which potentially contribute to the organismal aging. However, aging-associated changes of liver progenitor cells (LPCs) remain elusive. Employing young (2-month-old) and old (24-month-old) mice, we found diverse novel alterations in LPC activation during aging. LPCs in young mice could be activated and proliferate upon liver injury, whereas the counterparts in old mice failed to respond and proliferate, leading to the impaired liver regeneration. Surprisingly, isolated LPCs from young and old mice did not exhibit significant difference in their clonogenic and proliferative capacity. Later, we uncovered that the decreased activation and proliferation of LPCs were due to excessive reactive oxygen species produced by neutrophils infiltrated into niche, which was resulted from chemokine production from activated hepatic stellate cells during aging. This study demonstrates aging-associated changes in LPC activation and reveals critical roles for the stem cell niche, including neutrophils and hepatic stellate cells, in the negative regulation of LPCs during aging.

Elevations of Thrombotic Biomarkers in Hemoglobin H Disease

BACKGROUND

Thalassemia is a group of hereditary hemoglobinopathies caused by decreased or absent synthesis of α and/or β globin chains. Studies have shown that hypercoagulability and thrombosis are common clinical symptoms in β-thalassemia, especially β-thalassemia intermedia, but little is known about in α-thalassemia. This study aims to examine phosphatidylserine (PS) levels, platelet activation, and coagulation markers in splenectomized (S) and nonsplenectomy (NS) patients with hemoglobin (Hb) H disease.

METHODS

The NS group comprised 20 patients (median age 15.0 years, range, 14-16.5 years), and the S group consisted of 11 patients (median age 16.4 years, range, 14-19.9 years) with Hb H disease; the control group consisted of 20 normal subjects. Hematological parameters were collected. Flow cytometry was used to measure PS exposure on red blood cells. The levels of intercellular adhesive molecule (ICAM)-1, tumor necrosis factor α (TNFα), β-thromboglobulin (TG) and prothrombin fragment 1 + 2 (F1.2) were determined using ELISA test kits.

RESULTS

Significant increases in the levels of PS, ICAM-1, TNFα, β-TG, and F1.2 were observed in both patient groups compared to normal controls (p < 0.01).

CONCLUSION

This observation indicates blood coagulation, endothelial injury, chronic low-grade inflammation, platelet activation, and thrombin generation are present in Hb H disease; these findings merit further assessment in a larger prospective cohort to establish possible links with thrombotic manifestations.

Identification of differentially expressed inflammatory factors in Wilms tumors and their association with patient outcomes

The present study aimed to identify differentially expressed inflammatory factors observed in Wilms tumors (WT), and to investigate the association of these factors with clinical stage, pathological type, lymph node metastasis and vascular involvement of WT. Surface-enhanced laser desorption/ionization-time of flight mass spectrometry was performed to screen differentially expressed proteins among WT and normal tissue pairs. Upregulated proteins in WT were separated and purified by solid phase extraction and Tricine SDS-PAGE, respectively. Following in-gel digestion, the peptide mixture was subjected to liquid chromatography mass spectrometry to identify proteins on the basis of their amino acid sequences. Immunohistochemistry was used to confirm the expression of differentially expressed inflammatory proteins. Of the proteins that were upregulated in WT, two proteins with mass/charge (m/z) ratio of 12,138 and 13,462 were identified as macrophage migration inhibitory factor (MIF) and C-X-C motif ligand 7 (CXCL7) chemokine, respectively. The expression of these two proteins was increased in WT compared with adjacent normal tissues and normal renal tissues, and increased with increasing clinical stage. In addition, their expression was significantly increased in patients with unfavorable pathological type, lymph node metastasis and vascular involvement compared with the groups with favorable type, and without lymph node metastasis or vascular involvement (P<0.05). Increased pro-inflammatory MIF and CXCL7 expression in WT is closely associated with the clinical stage, pathological type, lymph node metastasis and vascular involvement, and may represent biomarkers for the clinical diagnosis of WT.

Macrophages mediate cardioprotective cellular postconditioning in acute myocardial infarction

Ischemic injury in the heart induces an inflammatory cascade that both repairs damage and exacerbates scar tissue formation. Cardiosphere-derived cells (CDCs) are a stem-like population that is derived ex vivo from cardiac biopsies; they confer both cardioprotection and regeneration in acute myocardial infarction (MI). While the regenerative effects of CDCs in chronic settings have been studied extensively, little is known about how CDCs confer the cardioprotective process known as cellular postconditioning. Here, we used an in vivo rat model of ischemia/reperfusion (IR) injury-induced MI and in vitro coculture assays to investigate how CDCs protect stressed cardiomyocytes. Compared with control animals, animals that received CDCs 20 minutes after IR had reduced infarct size when measured at 48 hours. CDCs modified the myocardial leukocyte population after ischemic injury. Specifically, introduction of CDCs reduced the number of CD68+ macrophages, and these CDCs secreted factors that polarized macrophages toward a distinctive cardioprotective phenotype that was not M1 or M2. Systemic depletion of macrophages with clodronate abolished CDC-mediated cardioprotection. Using both in vitro coculture assays and a rat model of adoptive transfer after IR, we determined that CDC-conditioned macrophages attenuated cardiomyocyte apoptosis and reduced infarct size, thereby recapitulating the beneficial effects of CDC therapy. Together, our data indicate that CDCs limit acute injury by polarizing an effector macrophage population within the heart.

Specific molecular signatures predict decitabine response in chronic myelomonocytic leukemia

Myelodysplastic syndromes and chronic myelomonocytic leukemia (CMML) are characterized by mutations in genes encoding epigenetic modifiers and aberrant DNA methylation. DNA methyltransferase inhibitors (DMTis) are used to treat these disorders, but response is highly variable, with few means to predict which patients will benefit. Here, we examined baseline differences in mutations, DNA methylation, and gene expression in 40 CMML patients who were responsive or resistant to decitabine (DAC) in order to develop a molecular means of predicting response at diagnosis. While somatic mutations did not differentiate responders from nonresponders, we identified 167 differentially methylated regions (DMRs) of DNA at baseline that distinguished responders from nonresponders using next-generation sequencing. These DMRs were primarily localized to nonpromoter regions and overlapped with distal regulatory enhancers. Using the methylation profiles, we developed an epigenetic classifier that accurately predicted DAC response at the time of diagnosis. Transcriptional analysis revealed differences in gene expression at diagnosis between responders and nonresponders. In responders, the upregulated genes included those that are associated with the cell cycle, potentially contributing to effective DAC incorporation. Treatment with CXCL4 and CXCL7, which were overexpressed in nonresponders, blocked DAC effects in isolated normal CD34+ and primary CMML cells, suggesting that their upregulation contributes to primary DAC resistance.

Differential proteomic analysis of endemic and sporadic Epstein-Barr virus-positive and negative Burkitt lymphoma

BACKGROUND

Burkitt lymphoma (BL) is the most common non-Hodgkin lymphoma in children worldwide and the most common paediatric malignancy in sub-Saharan Africa. The endemic (eBL) and sporadic (sBL) variants have distinct epidemiologic and virologic characteristics. Although gene expression studies have defined the transcriptional profiles of both, their proteomic signatures have not been studied.

METHODS

We compared the proteomic expression profiles using differential mass spectrometry-based isotope tag for relative and absolute quantitation (iTRAQ) analysis of a cell line representing Epstein-Barr virus (EBV)+ eBL, EBV+ and EBV- sBL, and EBV+/- normal B cells from healthy donors.

RESULTS

In total, there were 144 differentially expressed proteins with a statistically significant false discovery rate (FDR) of ⩽0.2. Results revealed over-expression of specific proteins with well-established links to lymphomagenesis such as TUBB2C (FDR 0.05), UCHL1 (FDR 0.05) and HSP90AB1 (FDR 0.1). Distinct characteristics based upon the epidemiologic and virologic subtypes of BL were also identified. In sBL, PCNA (FDR 0.05) and SLC3A2 (FDR 0.1) were significantly over-expressed. In eBL, C1QBP (FDR 0.1) and ENO1 (FDR 0.25) were significantly over-expressed. Comparison of EBV+ to EBV- BL cell lines and B cells revealed significant over-expression of DDX3X (FDR 0.1). Proteins were validated using Western blot analysis.

CONCLUSION

Our results suggest unique signal transduction pathways associated with EBV infection and epidemiological subtype of BL that may contribute to lymphomagenesis. These proteomic findings provide potential diagnostic, prognostic and therapeutic links to BL.

The CXCL7/CXCR1/2 axis is a key driver in the growth of clear cell renal cell carcinoma

Mutations in the von Hippel-Lindau gene upregulate expression of the central angiogenic factor VEGF, which drives abnormal angiogenesis in clear cell renal cell carcinomas (ccRCC). However, the overexpression of VEGF in these tumors was not found to correlate with overall survival. Here, we show that the proangiogenic, proinflammatory cytokine CXCL7 is an independent prognostic factor for overall survival in this setting. CXCL7 antibodies strongly reduced the growth of ccRCC tumors in nude mice. Conversely, conditional overexpression of CXCL7 accelerated ccRCC development. CXCL7 promoted cell proliferation in vivo and in vitro, in which expression of CXCL7 was induced by the central proinflammatory cytokine interleukin (IL)-1β. ccRCC cells normally secrete low amounts of CXCL7; it was more highly expressed in tumors due to high levels of IL-1β there. We found that a pharmacological inhibitor of the CXCL7 receptors CXCR1 and CXCR2 (SB225002) was sufficient to inhibit endothelial cell proliferation and ccRCC growth. Because CXCR1 and CXCR2 are present on both endothelial and ccRCC cells, their inhibition affected both the tumor vasculature and the proliferation of tumor cells. Our results highlight the CXCL7/CXCR1/CXCR2 axis as a pertinent target for the treatment of ccRCC.

The possible diagnostic and prognostic use of systemic chemokine profiles in clinical medicine—the experience in acute myeloid leukemia from disease development and diagnosis via conventional chemotherapy to allogeneic stem cell transplantation

Chemokines are important regulators of many different biological processes, including (i) inflammation with activation and local recruitment of immunocompetent cells; (ii) angiogenesis as a part of inflammation or carcinogenesis; and (iii) as a bridge between the coagulation system and inflammation/immune activation. The systemic levels of various chemokines may therefore reflect local disease processes, and such variations may thereby be used in the routine clinical handling of patients. The experience from patients with myeloproliferative diseases, and especially patients with acute myeloid leukemia (AML), suggests that systemic plasma/serum cytokine profiles can be useful, both as a diagnostic tool and for prognostication of patients. However, cytokines/chemokines are released by a wide range of cells and are involved in a wide range of biological processes; the altered levels may therefore mainly reflect the strength and nature of the biological processes, and the optimal clinical use of chemokine/cytokine analyses may therefore require combination with organ-specific biomarkers. Chemokine levels are also altered by clinical procedures, therapeutic interventions and the general status of the patients. A careful standardization of sample collection is therefore important, and the interpretation of the observations will require that the overall clinical context is considered. Despite these limitations, we conclude that analysis of systemic chemokine/cytokine profiles can reflect important clinical characteristics and, therefore, is an important scientific tool that can be used as a part of future clinical studies to identify clinically relevant biomarkers.

Proteome-based biomarkers in pancreatic cancer

Pancreatic cancer, as a highly malignant cancer and the fourth cause of cancer-related death in world, is characterized by dismal prognosis, due to rapid disease progression, highly invasive tumour phenotype, and resistance to chemotherapy. Despite significant advances in treatment of the disease during the past decade, the survival rate is little improved. A contributory factor to the poor outcome is the lack of appropriate sensitive and specific biomarkers for early diagnosis. Furthermore, biomarkers for targeting, directing and assessing therapeutic intervention, as well as for detection of residual or recurrent cancer are also needed. Thus, the identification of adequate biomarkers in pancreatic cancer is of extreme importance. Recently, accompanying the development of proteomic technology and devices, more and more potential biomarkers have appeared and are being reported. In this review, we provide an overview of the role of proteome-based biomarkers in pancreatic cancer, including tissue, serum, juice, urine and cell lines. We also discuss the possible mechanism and prospects in the future. That information hopefully might be helpful for further research in the field.

The role of platelet factor 4 in radiation-induced thrombocytopenia

PURPOSE

Factors affecting the severity of radiation-induced thrombocytopenia (RIT) are not well described. We address whether platelet factor 4 (PF4; a negative paracrine for megakaryopoiesis) affects platelet recovery postradiation.

METHODS AND MATERIALS

Using conditioned media from irradiated bone marrow (BM) cells from transgenic mice overexpressing human (h) PF4 (hPF4+), megakaryocyte colony formation was assessed in the presence of this conditioned media and PF4 blocking agents. In a model of radiation-induced thrombocytopenia, irradiated mice with varying PF4 expression levels were treated with anti-hPF4 and/or thrombopoietin (TPO), and platelet count recovery and survival were examined.

RESULTS

Conditioned media from irradiated BM from hPF4+ mice inhibited megakaryocyte colony formation, suggesting that PF4 is a negative paracrine released in RIT. Blocking with an anti-hPF4 antibody restored colony formation of BM grown in the presence of hPF4+ irradiated media, as did antibodies that block the megakaryocyte receptor for PF4, low-density lipoprotein receptor-related protein 1 (LRP1). Irradiated PF4 knockout mice had higher nadir platelet counts than irradiated hPF4+/knockout litter mates (651 vs. 328 × 106/mcL, p = 0.02) and recovered earlier (15 days vs. 22 days, respectively, p <0.02). When irradiated hPF4+ mice were treated with anti-hPF4 antibody and/or TPO, they showed less severe thrombocytopenia than untreated mice, with improved survival and time to platelet recovery, but no additive effect was seen.

CONCLUSIONS

Our studies show that in RIT, damaged megakaryocytes release PF4 locally, inhibiting platelet recovery. Blocking PF4 enhances recovery while released PF4 from megakaryocytes limits TPO efficacy, potentially because of increased release of PF4 stimulated by TPO. The clinical value of blocking this negative paracrine pathway post-RIT remains to be determined.

Paracrine regulation of megakaryo/thrombopoiesis by macrophages

OBJECTIVE

Megakaryo/thrombopoiesis is a complex process regulated by multiple signals provided by the bone marrow microenvironment. Because macrophages are relevant components of the bone marrow stroma and their activation induces an upregulation of molecules that can regulate hematopoiesis, we analyzed the impact of these cells on the control of megakaryocyte development and platelet biogenesis.

MATERIALS AND METHODS

The different stages of megakaryo/thrombopoiesis were analyzed by flow cytometry using an in vitro model of human cord blood CD34(+) cells stimulated with thrombopoietin in either a transwell system or conditioned media from monocyte-derived macrophages isolated from peripheral blood. Cytokines secreted from macrophages were characterized by protein array and enzyme-linked immunosorbent assay.

RESULTS

Resting macrophages released soluble factors that promoted megakaryocyte growth, cell ploidy, a size increase, proplatelet production, and platelet release. Lipopolysaccharide stimulation triggered the secretion of cytokines that exerted opposite effects together with a dramatic switch of CD34(+) commitment to the megakaryocytic lineage toward the myeloid lineage. Neutralization of interleukin-8 released by stimulated macrophages partially reversed the inhibition of megakaryocyte growth. Activation of nuclear factor κB had a major role in the synthesis of molecules involved in the megakaryocyte inhibition mediated by lipopolysaccharide-stimulated macrophages.

CONCLUSIONS

Our study extends our understanding about the role of the bone marrow microenvironment in the regulation of megakaryo/thrombopoiesis by showing that soluble factors derived from macrophages positively or negatively control megakaryocyte growth, differentiation, maturation, and their ability to produce platelets.

MiR-886-3p down regulates CXCL12 (SDF1) expression in human marrow stromal cells

Stromal Derived Factor 1 (SDF1 or CXCL12), is a chemokine known to be critical for the migration of cells in several tissue systems including the homing of the hematopoietic stem cell (HSC) to its niche in the bone marrow. A comparative analysis of miRNA expression profiles of two stromal cell lines, distinguishable by function and by CXCL12 expression (CXCL12⁺ and CXCL12⁻), revealed that the CXCL12⁻ cells expressed >40 fold more miR-886-3p than the CXCL12⁺ cells. Screening studies showed that when miR-886-3p was transfected into the CXCL12⁺ stromal cells, the expression of CXCL12 was down-regulated by as much as 85% when compared to appropriate controls, and results in the loss of CXCL12-directed chemotaxis. Similar reductions in CXCL12 were obtained with the transfection of miR-886-3p into primary stromal cell cultures. Additional studies showed that miR-886-3p specifically targeted the 3′ untranslated region (UTR) of CXCL12 mRNA. These data suggest a role for miRNA in modulating the expression of CXCL12, a gene product with a critical role in hematopoietic regulation.

Reduced plasma level of CXC chemokine ligand 7 in patients with pancreatic cancer

BACKGROUND

Early detection is essential to improve the outcome of patients with pancreatic cancer. A noninvasive and cost-effective diagnostic test using plasma/serum biomarkers would facilitate the detection of pancreatic cancer at the early stage.

METHODS

Using a novel combination of hollow fiber membrane-based low-molecular-weight protein enrichment and LC-MS-based quantitative shotgun proteomics, we compared the plasma proteome between 24 patients with pancreatic cancer and 21 healthy controls (training cohort). An identified biomarker candidate was then subjected to a large blinded independent validation (n = 237, validation cohort) using a high-density reverse-phase protein microarray.

RESULTS

Among a total of 53,009 MS peaks, we identified a peptide derived from CXC chemokine ligand 7 (CXCL7) that was significantly reduced in pancreatic cancer patients, showing an area under curve (AUC) value of 0.84 and a P value of 0.00005 (Mann-Whitney U test). Reduction of the CXCL7 protein was consistently observed in pancreatic cancer patients including those with stage I and II disease in the validation cohort (P < 0.0001). The plasma level of CXCL7 was independent from that of CA19-9 (Pearson's r = 0.289), and combination with CXCL7 significantly improved the AUC value of CA19-9 to 0.961 (P = 0.002).

CONCLUSIONS

We identified a significant decrease of the plasma CXCL7 level in patients with pancreatic cancer, and combination of CA19-9 with CXCL7 improved the discriminatory power of the former for pancreatic cancer.

IMPACT

The present findings may provide a new diagnostic option for pancreatic cancer and facilitate early detection of the disease.

Platelet-derived chemokines: pathophysiology and therapeutic aspects

The identification of chemokines in blood platelets has strengthened our view of these cells as participants in immune host defense. Platelet chemokines representing prestored and rapidly releasable proteins may play a major role as first-line inflammatory mediators. This is evident from their capability to recruit early inflammatory cells such as neutrophil granulocytes and monocytes and even to exhibit direct antimicrobial activity. However, insight is growing that platelet chemokines may be also long-term regulators, e.g., by activating T lymphocytes, by modulating the formation of endothelium and even thrombocytopoiesis itself. This review deals with the individual and cooperative functionality of platelet chemokines, as well as their potential as a basis for therapeutic intervention in the pathology of inflammation, infection, allergy and tumors. Within this context, therapeutic strategies based on the use of antibodies, modified chemokines, chemokine-binding proteins and chemokine receptor antagonists as well as first clinical studies will be addressed.

Canine CXCL7 and its functional expression in dendritic cells undergoing maturation

Many cells, including leucocytes and stromal cells, express CXCL7, a member of the CXC chemokine family, also known as platelet basic protein. CXCL7 is a potent chemoattractant and activator of neutrophil function. Dendritic cells (DCs) play a pivotal role in antigen processing and presentation. Very little information is available on the ability of DCs to recruit neutrophils by producing chemokines. In this work, we have cloned canine CXCL7. Based on the predicted gene sequence and using the 3'RACE technique, the full-length gene was amplified from LPS-treated canine peripheral blood mononuclear cells. The cloned cDNA sequence consisted of 357 nucleotides and encoded a 118 amino acid protein, including a 38 amino acid signal peptide. The use of CXCL7-containing supernatants from CXCL7-transfected BALB/3T3 in the neutrophil migration assay confirmed that canine CXCL7 had chemoattractive activity for neutrophils. We then used canine monocyte-derived DCs to generate CXCL7 for the rest of the experiment. Expression of CXCL7 by DCs treated with LPS, IL-1beta, IL-6, TGF-beta, TNF-alpha, or IFN-gamma was compared using real-time RT-PCR and Western blotting. When treated with IL-1beta, IL-6, TNF-alpha, or TGF-beta, canine DCs expressed significantly higher levels of CXCL7 mRNA and protein than when treated with IFN-gamma or LPS. It is concluded that dog DCs express high levels of the neutrophil chemotactic factor CXCL7 when stimulated by proinflammatory cytokines, including IL-1beta, IL-6, TNF-alpha, or TGF-beta, and may play an important role in modulating inflammatory responses.

Platelet factor 4 regulates megakaryopoiesis through low-density lipoprotein receptor-related protein 1 (LRP1) on megakaryocytes

Platelet factor 4 (PF4) is a negative regulator of megakaryopoiesis, but its mechanism of action had not been addressed. Low-density lipoprotein (LDL) receptor-related protein-1 (LRP1) has been shown to mediate endothelial cell responses to PF4 and so we tested this receptor's importance in PF4's role in megakaryopoiesis. We found that LRP1 is absent from megakaryocyte-erythrocyte progenitor cells, is maximally present on large, polyploidy megakaryocytes, and near absent on platelets. Blocking LRP1 with either receptor-associated protein (RAP), an antagonist of LDL family member receptors, or specific anti-LRP1 antibodies reversed the inhibition of megakaryocyte colony growth by PF4. In addition, using shRNA to reduce LRP1 expression was able to restore megakaryocyte colony formation in bone marrow isolated from human PF4-overexpressing mice (hPF4(High)). Further, shRNA knockdown of LRP1 expression was able to limit the effects of PF4 on megakaryopoiesis. Finally, infusion of RAP into hPF4(High) mice was able to increase baseline platelet counts without affecting other lineages, suggesting that this mechanism is important in vivo. These studies extend our understanding of PF4's negative paracrine effect in megakaryopoiesis and its potential clinical implications as well as provide insights into the biology of LRP1, which is transiently expressed during megakaryopoiesis.

Connective tissue-activating peptide III: a novel blood biomarker for early lung cancer detection

PURPOSE

There are no reliable blood biomarkers to detect early lung cancer. We used a novel strategy that allows discovery of differentially present proteins against a complex and variable background.

METHODS

Mass spectrometry analyses of paired pulmonary venous-radial arterial blood from 16 lung cancer patients were applied to identify plasma proteins potentially derived from the tumor microenvironment. Two differentially expressed proteins were confirmed in 64 paired venous-arterial blood samples using an immunoassay. Twenty-eight pre- and postsurgical resection peripheral blood samples and two independent, blinded sets of plasma from 149 participants in a lung cancer screening study (49 lung cancers and 100 controls) and 266 participants from the National Heart Lung and Blood Institute Lung Health Study (45 lung cancer and 221 matched controls) determined the accuracy of the two protein markers to detect subclinical lung cancer.

RESULTS

Connective tissue-activating peptide III (CTAP III)/ neutrophil activating protein-2 (NAP-2) and haptoglobin were identified to be significantly higher in venous than in arterial blood. CTAP III/NAP-2 levels decreased after tumor resection (P = .01). In two independent population cohorts, CTAP III/NAP-2 was significantly associated with lung cancer and improved the accuracy of a lung cancer risk prediction model that included age, smoking, lung function (FEV(1)), and an interaction term between FEV(1) and CTAP III/NAP-2 (area under the curve, 0.84; 95% CI, 0.77 to 0.91) compared to CAPIII/NAP-2 alone.

CONCLUSION

We identified CTAP III/NAP-2 as a novel biomarker to detect preclinical lung cancer. The study underscores the importance of applying blood biomarkers as part of a multimodal lung cancer risk prediction model instead of as stand-alone tests.

Leukemia-associated antigens are critical for the proliferation of acute myeloid leukemia cells

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. With intensive induction therapy, most patients younger than 60 years achieve complete remission. However, even if these younger patients were treated intensively, more than 50% will relapse. Clinical results of patients older than 60 years are more unfavorable. Therefore, in all patients with AML, the overall survival is still low. In the past decade, several leukemia-associated antigens (LAA) have been identified in patients with acute myeloid leukemia. BAGE, BCL-2, OFA-iLRP, FLT3-ITD, G250, hTERT, PRAME, proteinase 3, RHAMM, survivin, and WT-1 are all LAAs that have been shown to induce CD8+ T-cell recognition and for some antigens also humoral immune responses. Interestingly, most of these LAAs are linked to cell cycle or proliferation. This article discusses the balance between LAA-driven leukemia cell expansion and the elimination of these cells through attacks on LAAs by the immune system. Current knowledge of the function and CD8+ T-cell recognition of LAAs is reviewed and an outlook is given on how to improve T-cell responses to LAAs in acute myeloid leukemia cells.

Platelet factor 4 is a negative autocrine in vivo regulator of megakaryopoiesis: clinical and therapeutic implications

Platelet factor 4 (PF4) is a negative regulator of megakaryopoiesis in vitro. We have now examined whether PF4 regulates megakaryopoiesis in vivo by studying PF4 knockout mice and transgenic mice that overexpress human (h) PF4. Steady-state platelet count and thrombocrit in these animals was inversely related to platelet PF4 content. Growth of megakaryocyte colonies was also inversely related to platelet PF4 content. Function-blocking anti-PF4 antibody reversed this inhibition of megakaryocyte colony growth, indicating the importance of local PF4 released from developing megakaryocytes. The effect of megakaryocyte damage and release of PF4 on 5-fluorouracil-induced marrow failure was then examined. Severity of thrombocytopenia and time to recovery of platelet counts were inversely related to initial PF4 content. Recovery was faster and more extensive, especially in PF4-overexpressing mice, after treatment with anti-PF4 blocking antibodies, suggesting a means to limit the duration of such a chemotherapy-induced thrombocytopenia, especially in individuals with high endogenous levels of PF4. We found that approximately 8% of 250 healthy adults have elevated (> 2 times average) platelet PF4 content. These individuals with high levels of platelet PF4 may be especially sensitive to developing thrombocytopenia after bone marrow injury and may benefit from approaches that block the effects of released PF4.

Reduced expression of inducible gelatinase B/matrix metalloproteinase-9 in monocytes from patients with myelodysplastic syndrome: Correlation of inducible levels with the percentage of cytogenetically marked cells and with marrow cellularity

Regulatory molecules produced by stromal cells are often membrane bound until cleaved by matrix metalloproteinases (MMPs); cleavage can either activate or inactivate regulatory functions. We report here that marrow stromal cells induce the expression of MMP-9 in monocytes. Induction was contact independent and could be reproduced with recombinant MCP-1/CCL2, whereas IL-6, M-CSF, G-CSF, GM-CSF, IL-8/CXCL8, SDF-1/CXCL12, and MGSA/CXCL1 did not have this effect. Stroma-induced levels of MMP-9 in the monocyte population from healthy donors were relatively consistent, whereas induced levels varied significantly (P < .001) in the CD14+ population from 27 patients with myelodysplastic syndrome (MDS). In patients with a clonal chromosomal marker, the level of inducible MMP-9 expression in the monocyte population was inversely correlated with the percentage of marker-positive cells (n = 11, P = .01), suggesting that the ability to induce MMP-9 may be compromised in clonally derived monocytes. The inducible levels of MMP-9 were also inversely correlated with marrow cellularity observed in biopsies from MDS patients (P < .001). We conclude that monocytes can express MMP-9 in response to stromal factors and that this response may be significantly decreased in MDS-derived monocytes.