Angiogenesis in hematologic malignancies

Exploring the impact of hydrogen sulfide on hematologic malignancies: A review

Hydrogen sulfide (H2S) is one of the three most crucial gaseous messengers in the body. The discovery of H2S donors, coupled with its endogenous synthesis capability, has sparked hope for the treatment of hematologic malignancies. In the last decade, the investigation into the impact of H2S has expanded, particularly within the fields of cardiovascular function, inflammation, infection, and neuromodulation. Hematologic malignancies refer to a diverse group of cancers originating from abnormal proliferation and differentiation of blood-forming cells, including leukemia, lymphoma, and myeloma. In this review, we delve deeply into the complex interrelation between H2S and hematologic malignancies. In addition, we comprehensively elucidate the intricate molecular mechanisms by which both H2S and its donors intricately modulate the progression of tumor growth. Furthermore, we systematically examine their impact on pivotal aspects, encompassing the proliferation, invasion, and migration capacities of hematologic malignancies. Therefore, this review may contribute novel insights to our understanding of the prospective therapeutic significance of H2S and its donors within the realm of hematologic malignancies.

Myeloma Microenvironmental TIMP1 Induces the Invasive Phenotype in Fibroblasts to Modulate Disease Progression

Tissue inhibitors of metalloproteinases (TIMPs) are endogenous matrix metalloproteinase inhibitors. TIMP1 is produced by cancer cells and has pleiotropic activities. However, its role and source in multiple myeloma (MM) are unclear. Here, we evaluated TIMP1 protein and mRNA levels in bone marrow (BM) plasma cells and assessed the effects of TIMP1 expression on fibroblast invasive capacity using three-dimensional spheroid cell invasion assays. TIMP1 mRNA and protein levels were elevated when patients progressed from monoclonal gammopathy of undetermined significance or smouldering myeloma to MM. Furthermore, TIMP1 levels decreased at complete response and TIMP1 protein levels increased with higher international staging. TIMP1 mRNA levels were markedly higher in extramedullary plasmacytoma and MM with t(4;14). Overall survival and post-progression survival were significantly lower in MM patients with high TIMP1 protein. Recombinant TIMP1 did not directly affect MM cells but enhanced the invasive capacity of fibroblasts; this effect was suppressed by treatment with anti-TIMP1 antibodies. Fibroblasts supported myeloma cell invasion and expansion in extracellular matrix. Overall, these results suggested that MM-derived TIMP1 induces the invasive phenotype in fibroblasts and is involved in disease progression. Further studies are required to elucidate the specific roles of TIMP1 in MM and facilitate the development of novel therapies targeting the TIMP1 pathway.

Nanomedicine as a magic bullet for combating lymphoma

Hematological malignancy like lymphoma originates in lymph tissues and has a propensity to spread across other organs. Managing such tumors is challenging as conventional strategies like surgery and local treatment are not plausible options and there are high chances of relapse. The advent of novel targeted therapies and antibody-mediated treatments has proven revolutionary in the management of these tumors. Although these therapies have an added advantage of specificity in comparison to the traditional chemotherapy approach, such treatment alternatives suffer from the occurrence of drug resistance and dose-related toxicities. In past decades, nanomedicine has emerged as an excellent surrogate to increase the bioavailability of therapeutic moieties along with a reduction in toxicities of highly cytotoxic drugs. Nanotherapeutics achieve targeted delivery of the therapeutic agents into the malignant cells and also have the ability to carry genes and therapeutic proteins to the desired sites. Furthermore, nanomedicine has an edge in rendering personalized medicine as one type of lymphoma is pathologically different from others. In this review, we have highlighted various applications of nanotechnology-based delivery systems based on lipidic, polymeric and inorganic nanomaterials that address different targets for effectively tackling lymphomas. Moreover, we have discussed recent advances and therapies available exclusively for managing this malignancy.

microRNAs Biogenesis, Functions and Role in Tumor Angiogenesis

microRNAs (miRNAs) are small non-coding RNA molecules, evolutionary conserved. They target more than one mRNAs, thus influencing multiple molecular pathways, but also mRNAs may bind to a variety of miRNAs, either simultaneously or in a context-dependent manner. miRNAs biogenesis, including miRNA transcription, processing by Drosha and Dicer, transportation, RISC biding, and miRNA decay, are finely controlled in space and time. miRNAs are critical regulators in various biological processes, such as differentiation, proliferation, apoptosis, and development in both health and disease. Their dysregulation is involved in tumor initiation and progression. In tumors, they can act as onco-miRNAs or oncosuppressor-miRNA participating in distinct cellular pathways, and the same miRNA can perform both activities depending on the context. In tumor progression, the angiogenic switch is fundamental. miRNAs derived from tumor cells, endothelial cells, and cells of the surrounding microenvironment regulate tumor angiogenesis, acting as pro-angiomiR or anti-angiomiR. In this review, we described miRNA biogenesis and function, and we update the non-classical aspects of them. The most recent role in the nucleus, as transcriptional gene regulators and the different mechanisms by which they could be dysregulated, in tumor initiation and progression, are treated. In particular, we describe the role of miRNAs in sprouting angiogenesis, vessel co-option, and vasculogenic mimicry. The role of miRNAs in lymphoma angiogenesis is also discussed despite the scarcity of data. The information presented in this review reveals the need to do much more to discover the complete miRNA network regulating angiogenesis, not only using high-throughput computational analysis approaches but also morphological ones.

Plasma Concentrations of Vascular Endothelial Growth Factor and Basic Fibroblast Growth Factor in Lymphoproliferative Disorders

Angiogenesis plays a major role in the development and progression of haematological malignancies. In our study we measured plasma concentrations of key angiogenic activators vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) using comercially available sandwich enzyme-linked immunosorbent assay (ELISA) in 37 patients with lymphoid malignancies and 20 healthy donors. We found a statistically significant increase in bFGF concentrations in patients with B-cell chronic lymphocytic leukemia (B-CLL, n=18) compared to the control group (median 118.8 vs. 9.3 pg/ml, p<0.001). However, we didn’t find any significant difference in VEGF concentrations between B-CLL patients and the control group. There was also no significant increase in bFGF or VEGF in patients with multiple myeloma (n=7) and non-Hodgkin’s lymphoma (n=12). Our pilot study shows that measurement of angiogenic activators in plasma is a feasible and reproducible method of angiogenesis assessment. Larger studies are needed for correlation between serum and plasma concentrations and detailed statistical evaluation including the impact on patients’ survival.

Nanomedicines for the treatment of hematological malignancies

Hematological malignancies (HM) are a collection of malignant transformations originating from cells in the primary or secondary lymphoid organs. Leukemia, lymphoma, and multiple myeloma comprise the three major types of HM. Current treatment consists of bone marrow transplantation, radiotherapy, immunotherapy and chemotherapy. Although, many chemotherapeutic drugs are clinically available for the treatment of HM, the use of these agents is limited due to dose-related toxicity and lack of specificity to tumor tissue. Moreover, the poor pharmacokinetic profile of most of the chemotherapeutics requires high dosage and frequent administration to maintain therapeutic levels at the target site, both increasing adverse effects. This underlines an urgent need for a suitable drug delivery system to improve efficacy, safety, and pharmacokinetic properties of conventional therapeutics. Nanomedicines have proven to enhance these properties for anticancer therapeutics. The most extensively studied nanomedicine systems are lipid-based nanoparticles and polymeric nanoparticles. Typically, nanomedicines are small sub-micron sized particles in the size range of 20-200 nm. The biocompatible and biodegradable nature of nanomedicines makes them attractive vehicles to improve drug delivery. Their small size allows them to extravasate and accumulate at malignant sites passively by means of the enhanced permeability and retention (EPR) effect, resulting from rapid angiogenesis and inflammation. Moreover, the specificity to the target tissue can be further enhanced by surface modification of nanoparticles. This review describes currently available therapies as well as limitations and potential advantages of nanomedicine formulations for treatment of various types of HM. Additionally, recent investigational and approved nanomedicine formulations and their limited applications in HM are discussed.

Quantification of VEGF Isoforms and VEGFR Transcripts by qRT-PCR and Their Significance in Acute Myeloid Leukemia

Vascular endothelial growth factor (VEGF) and its receptors are known to play an important role in normal and pathological hematopoiesis but the prognostic impact of VEGF isoform transcripts in acute myeloid leukemia (AML) has not been addressed. We conducted a single-institution prospective study to analyze the impact of these angiogenic factors and the expression of their receptors on the survival of adult patients newly diagnosed with AML. We investigated the levels of VEGF transcript isoforms VEGF121, -145, -165, -189 and -206 and their receptors, VEGFR-1 and VEGFR-2, using quantitative reverse transcriptase polymerase chain reaction assays in peripheral blood mononuclear cells (PBMCs) of 67 consecutive AML patients at diagnosis. VEGF total protein was measured for comparison with mRNA levels in PBMCs. The VEGF121 splice variant transcript in AML PBMCs was significantly higher than in the normal controls. VEGF transcripts were quantified in all samples while its protein was detected in 42/67 (63%) of AML samples. High levels of VEGF121, VEGF165 transcripts and VEGF protein in AML were significantly related to a worse prognosis when analyzing overall survival (p<0.0001, p=0.019 and p=0.012, respectively) or event-free survival (p<0.0001, p=0.010 and p=0.047) using univariate analysis. In multivariable analysis only VEGF121 expression remained an independent prognostic factor for either event-free survival or overall survival [aHR=8.83 (3.48–22.4), p<0.0001, and aHR=9.52 (3.41–26.6), p<0.0001]. No prognostic value was observed for the other isoforms and the two receptors. Our findings show that the level of VEGF121 mRNA in circulating cells from AML patients is a strong independent prognostic parameter, which could be useful in the management of unselected AML patients.

Urine angiostatin and VCAM-1 surpass conventional metrics in predicting elevated renal pathology activity indices in lupus nephritis

AIM

The goal of this study is to investigate how urinary angiostatin, vascular cell adhesion molecule 1 (VCAM-1) and established measures of renal function relate to specific histologic findings in paired kidney biopsy samples from patients with lupus nephritis (LN).

METHOD

Urine samples were collected from 54 LN patients together with paired kidney biopsy samples and examined for urinary angiostatin and VCAM-1 protein levels. Nonparametric tests were used to examine the association of both urinary biomarkers and established traditional laboratory markers of renal function with nine specific renal histologic features seen in LN, including glomerular leukocyte infiltration, endocapillary proliferation, cellular crescents, fibrinoid necrosis, wire loops, interstitial inflammation, glomerulosclerosis, fibrous crescents, tubular atrophy and interstitial fibrosis.

RESULTS

Compared to traditional renal disease metrics, both urinary angiostatin and VCAM-1 exhibited outstanding potential (area under the curve 0.97, 0.98, respectively) to predict renal biopsy activity index score ≥ 7, which is associated with poor long-term prognosis. Whereas urine VCAM-1 was most significantly associated with fibrous crescents, urine angiostatin was most significantly associated with endocapillary proliferation, cellular crescents, fibrinoid necrosis and fibrous crescents in concurrent renal biopsies.

CONCLUSION

Urinary angiostatin and VCAM-1 are predictive of specific histological changes in concurrent LN renal biopsies. Both urinary biomarkers are good candidates for use as noninvasive measures of renal pathology activity changes in LN.

Bone Marrow Stroma and Vascular Contributions to Myeloma Bone Homing

PURPOSE OF THE REVIEW

Herein we dissect mechanisms behind the dissemination of cancer cells from primary tumor site to the bone marrow, which are necessary for metastasis development, with a specific focus on multiple myeloma.

RECENT FINDINGS

The ability of tumor cells to invade vessels and reach the systemic circulation is a fundamental process for metastasis development; however, the interaction between clonal cells and the surrounding microenvironment is equally important for supporting colonization, survival, and growth in the secondary sites of dissemination. The intrinsic propensity of tumor cells to recognize a favorable milieu where to establish secondary growth is the basis of the "seed and soil" theory. This theory assumes that certain tumor cells (the "seeds") have a specific affinity for the milieu of certain organs (the "soil"). Recent literature has highlighted the important contributions of the vascular niche to the hospitable "soil" within the bone marrow. In this review, we discuss the crucial role of stromal cells and endothelial cells in supporting primary growth, homing, and metastasis to the bone marrow, in the context of multiple myeloma, a plasma cell malignancy with the unique propensity to primarily grow and metastasize to the bone marrow.

Microvessel Density as a Surrogate Prognostic Marker in Patients with Multiple Myeloma: A Meta-Analysis

BACKGROUND/AIMS

Bone marrow (BM) angiogenesis is considered a hallmark of multiple myeloma (MM) development and progression, and can be quantified with the use of microvessel density (MVD). The purpose of this study is to provide a review and a meta-analysis of the current literature regarding the prognostic value of MVD in the overall survival (OS) of MM patients.

METHODS

MEDLINE was screened for studies evaluating the OS of MM patients with regard to their MVD count in BM trephine. The pooled hazard ratio (HR) and its associated 95% confidence interval (CI) among MM patients with a high and low MVD count was the primary end point. Secondary outcomes included odds ratios (OR) for 12-, 36-, and 60-month survival.

RESULTS

Ten eligible trials were identified for the analysis of the primary end point and 9 for the secondary end points. Pooled HR for OS was 1.85 (95% CI: 1.25-2.73, p = 0.002). The pooled OR of survival were 1.59 (95% CI: 1.02-2.46, p = 0.04) at 12 months, 2.90 (95% CI: 1.68-5.03, p = 0.0001) at 36 months, and 3.42 (95% CI: 2.41-4.85, p < 0.00001) at 60 months, in favor of the low MVD group.

CONCLUSION

This meta-analysis provides persuasive evidence that MVD has significant impact on the clinical outcome of MM patients.

Suppression of Akt-HIF-1α signaling axis by diacetyl atractylodiol inhibits hypoxia-induced angiogenesis

Hypoxia-inducible factor (HIF)-1α is a key regulator associated with tumorigenesis, angiogenesis, and metastasis. HIF-1α regulation under hypoxia has been highlighted as a promising therapeutic target in angiogenesis-related diseases. Here, we demonstrate that diacetyl atractylodiol (DAA) from Atractylodes japonica (A. japonica) is a potent HIF-1α inhibitor that inhibits the Akt signaling pathway. DAA dose-dependently inhibited hypoxia-induced HIF-1α and downregulated Akt signaling without affecting the stability of HIF-1α protein. Furthermore, DAA prevented hypoxia-mediated angiogenesis based on in vitro tube formation and in vivo chorioallantoic membrane (CAM) assays. Therefore, DAA might be useful for treatment of hypoxia-related tumorigenesis, including angiogenesis. [BMB Reports 2016; 49(9): 508-513]

Bone Marrow Blood Vessels: Normal and Neoplastic Niche

Blood vessels are among the most important factors in the transport of materials such as nutrients and oxygen. This study will review the role of blood vessels in normal bone marrow hematopoiesis as well as pathological conditions like leukemia and metastasis. Relevant literature was identified by a Pubmed search (1992-2016) of English-language papers using the terms bone marrow, leukemia, metastasis, and vessel. Given that blood vessels are conduits for the transfer of nutrients, they create a favorable situation for cancer cells and cause their growth and development. On the other hand, blood vessels protect leukemia cells against chemotherapy drugs. Finally, it may be concluded that the vessels are an important factor in the development of malignant diseases.

Ursolic acid-loaded chitosan nanoparticles induce potent anti-angiogenesis in tumor

Angiogenesis provides necessary nutrients and oxygen for tumor growth and metastasis; thus, every stage of angiogenesis process is the potential target for cancer therapies. Ursolic acid (UA) is reported to decrease tumor burden through anti-angiogenesis pathway, but its poor water solubility greatly limits its efficiency and clinical application. Here, a simple method for preparing UA-loaded chitosan nanoparticles (CH-UA-NPs) with anti-angiogenesis and anti-tumor activity was demonstrated. In vitro, CH-UA-NPs could significantly inhibit the proliferation, migration, and tube formation of human umbilical vascular endothelial cells (HUVECs). After uptake by HUVECs, CH-UA-NPs were mainly localized in lysosomes and mitochondria, but not nuclei. CH-UA-NPs induced the destruction of lysosome membrane integrity, collapse of mitochondrial membrane potential, and reorganization of cell cytoskeleton. All these changes led to the apoptosis or necrosis in HUVECs. In vivo, CH-UA-NPs could inhibit the angiogenesis in chicken chorioallantoic membrane (CAM) model and H22 xenograft model. Notably, comparing with free UA, such synthesized CH-UA-NPs could save about tenfold of UA doses, implying that this could significantly decrease the side effects induced by high doses of UA in biological organism. Our data showed that CH-UA-NPs and this nanoparticle-based drug delivery system could be as a potential drug candidate for anti-angiogenesis treatment.

SWI/SNF chromatin-remodeling enzymes Brahma-related gene 1 (BRG1) and Brahma (BRM) are dispensable in multiple models of postnatal angiogenesis but are required for vascular integrity in infant mice

Background

Mammalian SWItch/Sucrose NonFermentable (SWI/SNF) adenosine triphosphate (ATP)‐dependent chromatin‐remodeling complexes play important roles in embryonic vascular development by modulating transcription of specific target genes. We sought to determine whether SWI/SNF complexes likewise impact postnatal physiological and pathological angiogenesis.

Methods and Results

Brahma‐related gene 1 (BRG1) and Brahma gene (BRM) are ATPases within mammalian SWI/SNF complexes and are essential for the complexes to function. Using mice with vascular‐specific mutations in Brg1 or with a global mutation in Brm, we employed 3 models to test the role of these ATPases in postnatal angiogenesis. We analyzed neonatal retinal angiogenesis, exercise‐induced angiogenesis in adult quadriceps muscles, and tumor angiogenesis in control and mutant animals. We found no evidence of defective angiogenesis in Brg1 or Brm mutants using these 3 models. Brg1/Brm double mutants likewise show no evidence of vascular defects in the neonatal retina or tumor angiogenesis models. However, 100% of Brg1/Brm‐double mutants in which Brg1 deletion is induced at postnatal day 3 (P3) die by P19 with hemorrhaging in the small intestine and heart.

Conclusions

Despite their important roles in embryonic vascular development, SWI/SNF chromatin‐remodeling complexes display a surprising lack of participation in the 3 models of postnatal angiogenesis we analyzed. However, these complexes are essential for maintaining vascular integrity in specific tissue beds before weaning. These findings highlight the temporal and spatial specificity of SWI/SNF activities in the vasculature and may indicate that other chromatin‐remodeling complexes play redundant or more essential roles during physiological and pathological postnatal vascular development.

Platelet-derived growth factors and receptors in Canine Lymphoma

Platelet-derived growth factors (PDGFs) belong to a family of polypeptide growth factors that signal through cell surface tyrosine kinase receptors to stimulate growth, proliferation and differentiation. Platelet-derived growth factor receptors (PDGFRs) are also considered important targets for specific kinase inhibitors in the treatment of several human tumours. The aim of this study was to investigate the role of PDGF-A, PDGF-B, PDGFR-α and PDGFR-β in canine lymphoma by determining gene and protein expression in lymph nodes of dogs with diffuse large B-cell lymphoma (DLBCL), peripheral T-cell lymphoma (PTCL), T-lymphoblastic lymphoma (T-LBL) and in healthy control dogs. One lymph node was also studied at the end of therapy in a subset of dogs in remission for DLBCL. In controls, PDGF-A, PDGFR-α and PDGFR-β mRNA levels were significantly higher than in DLBCLs, PTCLs and T-LBLs. However, PDGFR-α and PDGFR-β were minimally expressed by lymphocytes and plasma cells in normal lymph nodes as determined by immunohistochemistry, while neoplastic B and T cells showed the highest score (P <0.05). This discordant result may be compatible with the constitutive expression of these molecules by endothelial cells and fibroblasts in normal lymph nodes, thereby influencing gene expression results. Furthermore, these cells were not included in the immunohistochemical analysis. Similarly, dogs with DLBCL that were in remission at the end of therapy showed significantly higher gene expression of PDGFs and receptors than at the time of diagnosis and with an opposite trend to the protein assay. PDGF-B protein and mRNA were overexpressed in PTCLs and T-LBLs when compared with DLBCLs and controls (P <0.05). Additionally, there was a correlation between protein expression of PDGF-B and both PDGFRs in PTCLs and T-LBLs, suggesting an autocrine or paracrine loop in the aetiology of aggressive canine T-cell lymphomas. These data provide a rationale for the use of PDGFR antagonists in the therapy of aggressive T-cell lymphomas, but not in DLBCLs.

Monoclonal antibodies raised against 167-180 aa sequence of human carbonic anhydrase XII inhibit its enzymatic activity

Abstract Human carbonic anhydrase XII (CA XII) is a single-pass transmembrane protein with an extracellular catalytic domain. This enzyme is being recognized as a potential biomarker for different tumours. The current study was aimed to generate monoclonal antibodies (MAbs) neutralizing the enzymatic activity of CA XII. Bioinformatics analysis of CA XII structure revealed surface-exposed sequences located in a proximity of its catalytic centre. Two MAbs against the selected antigenic peptide spanning 167-180 aa sequence of CA XII were generated. The MAbs were reactive with recombinant catalytic domain of CA XII expressed either in E. coli or mammalian cells. Inhibitory activity of the MAbs was demonstrated by a stopped flow CO2 hydration assay. The study provides new data on the surface-exposed linear CA XII epitope that may serve as a target for inhibitory antibodies with a potential immunotherapeutic application.

ANGPT2 promoter methylation is strongly associated with gene expression and prognosis in chronic lymphocytic leukemia

Increasing evidence suggests a key role for angiopoietin-2 (ANGPT2) in influencing the aggressiveness of chronic lymphocytic leukemia (CLL). In the presence of vascular endothelial growth factor (VEGF), ANGPT2 causes vessel destabilization leading to neoangiogenesis. Accordingly, high expression levels of ANGPT2 and high degree of angiogenesis have consistently been associated with poor prognosis in CLL; however, the molecular mechanisms behind the variability in ANGPT2 expression are still to be discovered. Here, for the first time, we investigated the DNA methylation status of the ANGPT2 promoter in a large CLL cohort (n = 88) using pyrosequencing and correlated methylation data with ANGPT2 expression levels, prognostic factors and outcome. Importantly, methylation levels of the ANGPT2 gene correlated inversely with its mRNA expression levels (p<0.001). Moreover, low ANGPT2 methylation status was highly associated with adverse prognostic markers, shorter time to first treatment and overall survival. Finally, treatment with methyl inhibitors induced re-expression of ANGPT2 in two B-cell lymphoma cell lines, underscoring the importance of DNA methylation in regulating transcriptional silencing of this gene. In conclusion, we believe that the known variability in ANGPT2 expression among CLL patients could be explained by differential promoter DNA methylation and that low methylation levels of the ANGPT2 promoter have an adverse prognostic impact in CLL.

The role of vascular endothelial growth factor and matrix metalloproteinases in canine lymphoma: in vivo and in vitro study

BACKGROUND

Canine lymphoma represents the most frequent haematopoietic cancer and it shares some similarities with human non-Hodgkin lymphoma. Matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) play a coordinated role during invasion and proliferation of malignant cells; however, little is known about their role in canine haematologic malignancies. The aim of this study was to investigate the mRNA and protein expression of VEGF and the most relevant MMPs in canine lymphoma. Lymph node aspirates from 26 B-cell and 21 T-cell lymphomas were collected. The protein expression levels of MMP-9, MMP-2 and VEGF-A were evaluated by immunocytochemistry, and the mRNA levels of MMP-2, MMP-9, MT1-MMP, TIMP-1, TIMP-2, RECK, VEGF-A and VEGF-164 were measured using quantitative RT-PCR.

RESULTS

MT1-MMP, TIMP-1 and RECK mRNA levels were significantly higher in T-cell lymphomas than in B-cell lymphomas. Higher mRNA and protein levels of MMP-9 and VEGF-A were observed in T-cell lymphomas than in B-cell lymphomas and healthy control lymph nodes. A positive correlation was found between MMP-9 and VEGF-A in T-cell lymphomas. Moreover, MMP-9, MT1-MMP, TIMP-1 and VEGF-A were expressed at the highest levels in high-grade T-cell lymphomas.

CONCLUSIONS

This study provides new information on the expression of different MMPs and VEGF in canine lymphoma, suggesting a possible correlation between different MMPs and VEGF, immunophenotype and prognosis.

VEGF and MMP-9: biomarkers for canine lymphoma

Vascular endothelial growth factor (VEGF) and metalloproteinase (MMP) 2 and 9 are useful biomarkers in human lymphoma. During cancerogenesis, transforming growth factor beta (TGF-β) stimulates VEGF and MMPs production. VEGF and TGF-β plasma levels were tested by ELISA, MMP-2 and MMP-9 by gelatine zymography in 37 dogs with lymphoma, 13 of which were also monitored during chemotherapy. Ten healthy dogs served as control. Lymphoma dogs showed higher act-MMP-9 (P < 0.01) and VEGF (P < 0.05), and lower TGF-β than controls, and a positive correlation between act-MMP-9 and VEGF (P < 0.001). Act-MMP-9 and VEGF were significantly higher in T-cell lymphomas, and in stage V compared with stages III-IV disease, regardless of immunophenotype. VEGF was higher in high-grade compared with low-grade T-cell lymphomas. No correlation was found between cytokines levels at presentation and outcome. During chemotherapy, act-MMP-9 and VEGF decreased in B-cell lymphomas (P < 0.01), suggesting a possible predictive role in this group of dogs.

Strong cross-talk between angiogenesis and EBV: do we need different treatment approaches in lymphoma cases with EBV and/or high angiogenic capacity

Angiogenesis is the new blood vessels formation and is the critical event for the growth of malignant diseases and plays a key role in the development, invasion, and metastasis of malignant tumors. Epstein-Barr virus (EBV) is an important carcinogen causing to the some neoplastic disorders and lytically infected cells may contribute to the growth of EBV-associated malignancies, and this phenomenon is related with enhancing angiogenesis. Due to the strong cross-talk between angiogenesis and viral carcinogenesis and increased information about the angiogenesis and viral carcinogenesis in lymphomas, we need new therapeutic approaches to cases with lymphoma. Due to the strong cross-talk between angiogenesis and viral lymphomagenesis, this association was reviewed in this study.

SDF-1/CXCR4 axis in myelodysplastic syndromes: correlation with angiogenesis and apoptosis

To study the role of SDF-1/CXCR4 axis in MDS, the expression of SDF-1 and CXCR4, VEGF, MVD and apoptosis were measured in MDS. The results showed that the expression of SDF-1 of the low-grade MDS is higher than that of the high-grade MDS and the control. The high-grade MDS had a significantly higher CXCR4 expression on CD34+ cell than low-grade MDS and the control. It was suggested that the SDF-1/CXCR4 axis play an important role in MDS. Apoptosis was significantly increased in low-grade MDS, compared with high-grade MDS. The expression of VEGF and MVD were higher in the high-grade MDS than in the low-grade MDS. There are positive correlations between SDF-1 and apoptosis in the low-grade MDS. For the high-grade MDS, there were positive correlations between CXCR4 and VEGF, and between SDF-1 concentration and MVD. The apoptosis is one of the hallmarks for low-grade MDS and the angiogenesis for high-grade MDS. A refined understanding of the roles that SDF-1/CXCR4 axis and its correlation with angiogenesis and apoptosis play in MDS will fuel the development of therapies that can be targeted to the SDF-1/CXCR4 axis.

Effects of spironolactone and losartan on diabetic nephropathy in a type 2 diabetic rat model

BACKGROUND

While there is an evidence that the anti-inflammatory properties of spironolactone can attenuate proteinuria in type 2 diabetes, its effects on vascular endothelial growth factor (VEGF) expression in diabetic nephropathy have not been clearly defined. In this study, we examined the effects of spironolactone, losartan, and a combination of these two drugs on albuminuria, renal VEGF expression, and inflammatory and oxidative stress markers in a type 2 diabetic rat model.

METHODS

Thirty-three Otsuka-Long-Evans-Tokushima-Fatty (OLETF) rats were divided into four groups and treated with different medication regimens from weeks 25 to 50; OLETF diabetic controls (n=5), spironolactone-treated (n=10), losartan-treated (n=9), and combination of spironolactone- and losartan-treated (n=9).

RESULTS

At week 50, the albumin-to-creatinine ratio was significantly decreased in the losartan and combination groups compared to the control OLETF group. No decrease was detected in the spironolactone group. There was a significant reduction in renal VEGF, transforming growth factor (TGF)-β, and type IV collagen mRNA levels in the spironolactone- and combination regimen-treated groups. Twenty-four hour urine monocyte chemotactic protein-1 levels were comparable in all four groups but did show a decreasing trend in the losartan and combination regimen groups. Twenty-four hour urine malondialdehyde levels were significantly decreased in the spironolactone- and combination regimen-treated groups.

CONCLUSION

These results suggest that losartan alone and a combined regimen of spironolactone and losartan could ameliorate albuninuria by reducing renal VEGF expression. Also, simultaneous treatment with spironolactone and losartan may have protective effects against diabetic nephropathy by decreasing TGF-β and type IV collagen expression and by reducing oxidative stress in a type 2 diabetic rat model.

Targeting the microenvironment

The microenvironment in which cancer arises plays a critical role in tumorigenesis. Although previously regarded as an innocent bystander, evidence has accumulated over the past 10 years that the microenvironment contributes to tumor growth and progression by providing nutrients and survival signals, and protecting the tumor from normal immune responses and anticancer drugs. Exactly how normal stromal cells, whose function should be to suppress malignant growth, become co-opted into facilitating tumor development is only just beginning to be understood, but a complex story is emerging wherein tumor and stromal cells appear to co-evolve. A better understanding of tumor-stromal interactions and the molecular alterations that result in stromal dysfunction may help to identify patients who will benefit from either more aggressive or risk-adapted therapy regimens, and/or novel compounds that disrupt the tumor microenvironment and re-establishing normal control mechanisms.

ZFAT is essential for endothelial cell assembly and the branch point formation of capillary-like structures in an angiogenesis model

ZFAT, originally identified as a susceptibility gene for autoimmune thyroid disease, encodes a transcriptional regulator with one AT-hook and 18 C(2)H(2)-type zinc-finger domains. It is highly conserved among species. Here, we demonstrate that ZFAT is clearly expressed in human umbilical vein endothelial cells (HUVECs). Furthermore, we show that endothelial cell assembly and the branch point formation of capillary-like structures in HUVECs is impaired by the reduction of ZFAT expression through the use of ZFAT-miRNAs, whereas differences in cell proliferation or apoptotic features were not observed after the reduction in ZFAT expression. These results suggest that ZFAT may have critical roles in the capillary-like network formation that is involved in vascular remodeling. Elucidating the ZFAT-mediated transcriptional network will lead to a better understanding of the molecular mechanisms of angiogenesis.

Molecular and biologic markers of progression in monoclonal gammopathy of undetermined significance to multiple myeloma

Multiple myeloma (MM) is a malignant plasma cell dyscrasia localized in the bone marrow. Recent studies have shown that MM is preceded in virtually all cases by a premalignant state called monoclonal gammopathy of undetermined significance (MGUS). This review focuses on non-IgM MGUS and its progression to MM. Although certain clinical markers of MGUS progression have been identified, it currently is not possible to accurately determine individual risk of progression. This review focuses on the various biologic and molecular markers that could be used to determine the risk of MM progression. A better understanding of the pathogenesis will allow us to define the biological high-risk precursor disease and, ultimately, to develop early intervention strategies designed to delay and prevent full-blown MM.

Biological impact of vascular endothelial growth factor on vessel density and survival in multiple myeloma and plasmacytoma

We compared the differences in a number of angiogenesis-related immunohistochemical parameters, including microvascular density (MVD) and tumor cell activity, between multiple myeloma (MM) and solitary plasmacytoma (SP). Tissue sections from tumors of MM and SP were immunohistochemically stained and analyzed using ImageJ image analysis software for the expression of vascular endothelial growth factor (VEGF), VEGF receptors (Flt-1 and Flk-1), inducible nitric oxide (iNOS), and anti-apoptotic (Bcl-2) protein. Tumor tissues were cytologically graded as high-, intermediate-, or low-grade. Two pathologists determined the MVD of each section independently by recording the average number of CD34+ blood vessels in 500 unit fields. The arithmetic means for MVD were statistically analyzed using the Student's t-test and the significance level was calculated at P-value <0.001. The results indicate a direct correlation between upregulation of iNOS/VEGF in high-grade tumors. For MM, an increase in MVD is also correlated with a high-grade. Tumor survival signaling by Bcl-2 in both SP and MM emphasizes the fact that VEGF has a bimodal role that is mainly angiogenic in MM and tumorigenic, promoting tumor cell survival in SP.

Phage-derived fully human monoclonal antibody fragments to human vascular endothelial growth factor-C block its interaction with VEGF receptor-2 and 3

Vascular endothelial growth factor C (VEGF-C) is a key mediator of lymphangiogenesis, acting via its receptors VEGF-R2 and VEGF-R3. High expression of VEGF-C in tumors correlates with increased lymphatic vessel density, lymphatic vessel invasion, sentinel lymph node metastasis and poor prognosis. Recently, we found that in a chemically induced skin carcinoma model, increased VEGF-C drainage from the tumor enhanced lymphangiogenesis in the sentinel lymph node and facilitated metastatic spread of cancer cells via the lymphatics. Hence, interference with the VEGF-C/VEGF-R3 axis holds promise to block metastatic spread, as recently shown by use of a neutralizing anti-VEGF-R3 antibody and a soluble VEGF-R3 (VEGF-C/D trap). By antibody phage-display, we have developed a human monoclonal antibody fragment (single-chain Fragment variable, scFv) that binds with high specificity and affinity to the fully processed mature form of human VEGF-C. The scFv binds to an epitope on VEGF-C that is important for receptor binding, since binding of the scFv to VEGF-C dose-dependently inhibits the binding of VEGF-C to VEGF-R2 and VEGF-R3 as shown by BIAcore and ELISA analyses. Interestingly, the variable heavy domain (V_H) of the anti-VEGF-C scFv, which contains a mutation typical for camelid heavy chain-only antibodies, is sufficient for binding VEGF-C. This reduced the size of the potentially VEGF-C-blocking antibody fragment to only 14.6 kDa. Anti-VEGF-C V_H-based immunoproteins hold promise to block the lymphangiogenic activity of VEGF-C, which would present a significant advance in inhibiting lymphatic-based metastatic spread of certain cancer types.

Overexpression of the natural tetrapeptide acetyl-N-ser-asp-lys-pro derived from thymosin beta4 in neoplastic diseases

The natural tetrapeptide acetyl-ser-asp-lys-pro (AcSDKP) is formed in vivo by enzymatic cleavage of the N terminus of thymosin beta4 by prolyl oligopeptidase (POP). Recently, AcSDKP was shown to promote angiogenesis. Because of the critical role of neovascularization in cancer development, the levels of AcSDKP and POP activity in a number of different malignant tissues were investigated. Our studies revealed that AcSDKP levels were markedly elevated in neoplastic diseases including hematologic malignancies and solid neoplasms. Consistent with this finding, the enhanced activity of POP was also detected in all analyzed specimens of cancer tissues. Both these novel findings are in concert with the previously reported overexpression of thymosin beta4 in a large variety of malignant tumors and with its potential role in cancerogenesis. The physiological relevance of these findings awaits further studies; however, our first results strongly suggest a key role for AcSDKP in the pathogenesis of cancer.

Changes in magnetic resonance bone marrow angiogenesis on day 7 after induction chemotherapy can predict outcome of acute myeloid leukemia

Recently, dynamic contrast-enhanced magnetic resonance imaging has been shown to be a non-invasive technique that provides global and functional imaging of bone marrow angiogenesis in acute myeloid leukemia. To assess the clinical implication of changes in angiogenesis shortly after induction chemotherapy, dynamic contrast-enhanced magnetic resonance imaging was performed prospectively before treatment (day 0) and on day 7 in 80 patients with de novo acute myeloid leukemia. We demonstrated that a post-therapeutic reduction in Peak (negative DeltaPeak) compared with the day 0 value was significantly associated with a higher chance of achieving complete remission, and better overall and disease free survival (P=0.022, 0.003 and 0.007, respectively). Cox's multivariate analysis also identified negative DeltaPeak value as an independent good prognostic factor for overall and disease free survival. Our findings provide evidence that the change of Peak on day 7 relative to pre-treatment levels may be a relevant biomarker for early identification of patients who may fail conventional induction chemotherapy (ClinicalTrials.gov Identifier: NCT00172562).

Transcriptional regulation of the vascular endothelial glycome by angiogenic and inflammatory signalling

Vascular endothelial cells undergo many molecular changes during pathological processes such as inflammation and tumour development. Tumours such as malignant lymphomas affecting bone marrow are dependent on interactions with endothelial cells for (1) site-specific homing and (2) tumour-induced angiogenesis. Modifications in glycosylation are responsible for fine-tuning of distinct endothelial surface receptors. In order to gain a comprehensive insight into the regulation of the endothelial glycome, comprising genes encoding for sugar transporters (sugar s/t), glycosyltransferases (GT), glycan-degrading enzymes (GD) and lectins (GBP), we performed gene profiling analysis of the human bone marrow-derived microvascular endothelial cell line HBMEC-60 that resembles closely in its biological behaviour primary bone marrow endothelial cells. HBMEC were activated by either angiogenic VEGF or the inflammatory cytokine TNF. Approximately 48% (207 genes) of the 432 glycome genes tested were found to be expressed in HBMEC-60 cells. Inflammatory and angiogenic signals produce different profiles of up- or down-regulated glycome genes, most prominent changes were seen under TNF stimulation in terms of signal intensity and number of alterations. Stimulation by VEGF and TNF affected primarily genes encoding for glycosyltransferases and in particular those important for terminal modulation. For instance, an enhanced alpha2,6 sialylation was observed after TNF stimulation at the transcriptional and glycan expression level whereas transcription of ST3Gal1 sialylating in alpha2,3 position was enhanced after VEGF stimulation. Transcriptional analysis of the glycome gives insights into the differential regulation of glycosylation pathways and may help to understand the functional impact of endothelial glycosylation.

Primary human acute myelogenous leukemia cells release matrix metalloproteases and their inhibitors: release profile and pharmacological modulation

OBJECTIVES

Angiogenesis seems important for both leukemogenesis and chemosensitivity in acute myelogenous leukemia (AML). Angiogenesis is regulated by the balance between pro- and antiangiogenic cytokines, which also indicates an important role of matrix metalloproteases (MMPs) and their natural inhibitors, tissue inhibitors of metalloproteases (TIMPs). We investigated the constitutive release of MMPs and TIMPs for a large group of consecutive AML patients.

METHODS

AML cells were cultured in vitro either alone or together with microvascular endothelial cells, and levels of MMPs and TIMPs were determined in culture supernatants.

RESULTS

AML cells showed constitutive release of several MMPs and TIMPs. For all patients, detectable MMP-10 release was observed, and most patients showed detectable release of at least one additional MMP, usually MMP-9 or MMP-2. A significant correlation was found between MMP-9 and TIMP-1 release and the release of several CCL and CXCL chemokines. MMP-9 release was higher for AML cells with monocytic differentiation corresponding to the FAB-subtype M4/M5 AML; it was mainly released in its inactive form, but endogenously active MMP-9 could be detected even in the presence of the constitutively released TIMP-1/2. Endothelial cells released relatively high levels of MMP-10, and these levels were further increased by coculture with AML cells. Patients achieving complete hematological remission after only one induction cycle showed relatively low constitutive MMP-2 release.

CONCLUSION

We conclude that primary human AML cells show constitutive release of both MMPs and TIMPs, and this release may be important for leukemogenesis and possibly also for chemosensitivity.

Alterations in regulators of the extracellular matrix in non-Hodgkin lymphomas

Bone marrow angiogenesis is increased in non-Hodgkin lymphomas (NHL). Compounds affecting extracellular matrix (ECM) may modify angiogenesis. Here we investigated ECM regulators in 48 unselected NHL patients compared with 35 controls. Untreated patients had elevated (P < 0.05) serum matrix metalloproteinase (MMP) 9 and tissue inhibitor of metalloproteinase (TIMP) 1, while MMP-2, TIMP-2 and syndecan-1 were not significantly different from controls. MMP-9 mRNA was significantly up-regulated in blood mononuclear cells, while mRNA expressions of the other ECM regulators were unaltered. We found strong correlations between mRNA expressions of both vascular endothelial growth factor and fibroblast growth factor 2, and MMP-9, TIMP-1 and TIMP-2. After therapy, serum MMP-2 increased while MMP-9 decreased (P < 0.05), the others being unchanged. Several compounds affecting ECM may be involved in angiogenic activity in NHL.

The prognostic significance of VEGF-C and VEGF-A in non-Hodgkin lymphomas

Angiogenesis and lymphangiogensis are important in the proliferation and survival of the malignant hemeopoietic neoplasms. The aim of this study is to determine the prognostic role of angiogenesis and lymphangiogenesis in the development of lymphoma. For this aim, VEGF-A and VEGF-C were explored by immunohistochemistry in 177 cases. VEGF-C and VEGF-A were found to be positive in 34 and 61% of the samples. There was a good correlation between VEGF-C and VEGF-A expression (p = 0.0001). The clinical prognostic indicators were not significantly different between VEGF-C (+) and (-) and/or VEGF-A (+) and (-) cases. Overall survival (OS) rate was shorter in cases with VEGF-A (+) and VEGF-C (+) cases than with negative cases (p = 0.03 and p = 0.0005, respectively). The OS was significantly shorter in aggressive lymphomas expressing VEGF-A and VEGF-C but not in indolent lymphomas. The results of Cox regression analyses showed that VEGF-A and VEGF-C expressions are independent prognostic parameters (OR: 2.6, 95% CI: 1.3-5.0 for both (+) cases). In conclusion, VEGF-C and VEGF-A were positive in 34 and 61%, respectively, of the cases with NHL. The significant correlation between VEGF-C and VEGF-A suggests that lymphangiogenesis is important in the pathogenesis of lymphomas as shown in angiogenesis. The significantly shorter survival rates of VEGF-C and/or VEGF-A expressions indicate that angiogenesis and lymphangiogenesis are important in clinical outcome. Autocrine VEGF-A and VEGF-C crosstalks in lymphoma cells are important in lymphoma biology and inhibition of these signals with anti-angiogenic/anti-lymphangiogenic drugs and combination with chemo-immunotherapy regimens will be more useful in these cases.

Induction of angiogenesis by normal and malignant plasma cells

Abundant bone marrow angiogenesis is present in almost all myeloma patients requiring therapy and correlated to treatment response and survival. We assessed the expression of 402 angiogenesis-associated genes by Affymetrix DNA microarrays in 466 samples, including CD138-purified myeloma cells (MMCs) from 300 previously untreated patients, in vivo microcirculation by dynamic contrast-enhanced magnetic resonance imaging, and in vitro angiogenesis (AngioKit-assay). Normal bone marrow plasma cells (BMPCs) express a median of 39 proangiogenic (eg, VEGFA, ADM, IGF-1) and 28 antiangiogenic genes (eg, TIMP1, TIMP2). Supernatants of BMPCs unlike those of memory B cells induce angiogenesis in vitro. MMCs do not show a significantly higher median number of expressed proangiogenic (45) or antiangiogenic (31) genes, but 97% of MMC samples aberrantly express at least one of the angiogenic factors HGF, IL-15, ANG, APRIL, CTGF, or TGFA. Supernatants of MMCs and human myeloma cell lines induce significantly higher in vitro angiogenesis compared with BMPCs. In conclusion, BMPCs express a surplus of proangiogenic over antiangiogenic genes transmitting to the ability to induce in vitro angiogenesis. Aberrant expression of proangiogenic and down-regulation of antiangiogenic genes by MMCs further increases the angiogenic stimulus, together leading to bone marrow angiogenesis at various degrees in all myeloma patients.

Dynamic contrast-enhanced magnetic resonance imaging identifies a subgroup of patients with asymptomatic monoclonal plasma cell disease and pathologic microcirculation

PURPOSE

The aim of our study was to investigate whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) allows visualization of changes in microcirculation between healthy controls on the one side and early/advanced stages of plasma cell disease on the other.

EXPERIMENTAL DESIGN

We examined a group of 222 individuals consisting of 60 patients with monoclonal gammopathy of undetermined significance (MGUS), 65 patients with asymptomatic multiple myeloma (aMM), 75 patients with newly diagnosed symptomatic MM (sMM), and 22 healthy controls with DCE-MRI of the lumbar spine.

RESULTS

A continuous increase in microcirculation parameters amplitude A and exchange rate constant kep reflecting vascular volume and permeability, respectively, was detected from normal controls over MGUS and aMM to sMM. For A and kep, significant differences were found between controls and aMM (P = 0.03 and P = 0.004, respectively) as well as controls and sMM (P = 0.001 and P < 0.001, respectively). Although diffuse microcirculation patterns were found in healthy controls as well as MGUS and MM, a pattern with focal hotspots was exclusively detected in 42.6% of sMM and in 3 MGUS and 3 aMM patients. MGUS and aMM patients with increased microcirculation patterns showed significantly higher bone marrow plasmocytosis compared with patients with a low microcirculation pattern.

CONCLUSIONS

Our investigations substantiate the concept of an angiogenic switch from early plasma cell disorders to sMM. Pathologic DCE-MRI findings correlate with adverse prognostic factors and DCE-MRI identifies a distinct group of patients with increased microcirculation parameters in aMM and MGUS patients.

Bone marrow angiogenesis magnetic resonance imaging in patients with acute myeloid leukemia: peak enhancement ratio is an independent predictor for overall survival

Emerging evidence suggests that progression of hematologic malignancies is associated with angiogenesis. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can provide global and functional imaging of tumor angiogenesis. In this study, we performed bone marrow DCE-MRI prospectively at diagnosis and after induction chemotherapy in 78 de novo acute myeloid leukemia (AML) patients and correlated it with treatment outcome. An algorithm to assess bone marrow angiogenesis by measuring the DCE-MRI time-intensity curve pixel by pixel was developed using 3 distinct parameters: peak enhancement ratio (Peak) to indicate tissue blood perfusion; amplitude (Amp) to reflect vascularity; and volume transfer constant (K trans) to indicate vascular permeability. The Peak and Amp decreased significantly at remission status after induction chemotherapy. Patients with higher Peak or Amp at diagnosis had shorter overall survival and disease-free survival than others. Cox multivariate analysis identified higher Peak value (hazard ratio, 9.181; 95% confidence interval, 1.740-48.437; P = .009) as an independent predictor for overall survival in addition to unfavorable karyotype and old age. Our findings provide evidence that increased bone marrow angiogenesis measured by DCE-MRI can predict adverse clinical outcome in AML patients. DCE-MRI may help to select high-risk phenotype AML patients for tailored antiangiogenic therapy and to monitor treatment response.

(+)-Catechin inhibits tumour angiogenesis and regulates the production of nitric oxide and TNF-α in LPS-stimulated macrophages

The anti-angiogenic activity of (+)-catechin as well as its regulatory effect on the production of nitric oxide and TNFα were studied using in vivo and in vitro models. In vivo angiogenic activity was studied using B16F-10 melanoma cell-induced capillary formation in C57BL/6 mice. Administration of (+)-catechin significantly inhibited (36.09%) the number of tumour-directed capillaries induced by injecting B16F-10 melanoma cells on the ventral side of C57BL/6 mice. The cytokine profile in the serum of these animals showed a drastically increased level of proinflammatory cytokines such as IL-1β, IL-6, TNF-α, GM-CSF and the direct endothelial cell proliferating agent, VEGF. Administration of (+)-catechin could differentially regulate elevation of these cytokines. The differential elevation is further evidenced by the increased production of IL-2 and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the B16F-10 injected, (+)-catechin-treated animals. In vitro L929 bioassay revealed the inhibition of TNF-α production by (+)-catechin treatment. In the rat aortic ring assay, (+)-catechin inhibited the microvessel outgrowth at non-toxic concentrations. (+)-Catechin at non-toxic concentrations (5—25 µg/ml) showed significant inhibition in the proliferation, migration and tube formation of endothelial cells, which are the key events in the process of angiogenesis. (+)-Catechin also showed inhibitory effect on VEGF mRNA levels in B16F-10 melanoma cells. (+)-Catechin inhibited the production of NO and TNF-α in LPS-stimulated primary macrophages. Taken together, these results demonstrate that (+)-catechin inhibits tumour-specific angiogenesis by regulating the production of pro- and anti-angiogenic factors such as pro-inflammatory cytokines, nitric oxide, VEGF, IL-2 and TIMP-1. These results also suggest that (+)-catechin could significantly inhibit nitrite and TNF-α production in LPS-stimulated macrophages.