Vascular endothelial growth factor and its receptors in multiple myeloma

Multiple myeloma (MM) progresses from an avascular to a vascular phase (active MM) accompanied by a significant increase in microvessel density in the bone marrow. This article summarizes the literature concerning the specific role played by vascular endothelial growth factor (VEGF) in this process. Recent applications of antiangiogenic agents that interfere with VEGF signaling and block MM progression are also described.

Detection of early impairment of coronary flow reserve in patients with systemic sclerosis

OBJECTIVE

To investigate whether coronary flow reserve (CFR), measured by a new non-invasive method, is impaired early in patients with systemic sclerosis (SSc) and whether CFR impairment correlates with clinical or functional measures, or both.

METHODS

27 patients with SSc without clinical evidence of ischaemic heart disease and 23 control group subjects matched for age and sex were studied. CFR was evaluated in the left anterior descending coronary artery (LAD) with a new non-invasive method: contrast (Levovist) enhanced transthoracic Doppler during adenosine infusion. The pulsed wave Doppler examination of blood flow velocity was recorded in the LAD at rest and after maximum vasodilatation by adenosine infusion.

RESULTS

In patients with SSc, without clinical evidence of ischaemic heart disease, CFR was impaired (p=0.0001). 14/27 patients with SSc had severe reduction of the CFR (< or =2.5) compared with controls (p=0.002). A non-significant trend between mean CFR and the severity and duration of the disease was also seen.

CONCLUSIONS

CFR is often reduced in patients with SSc, suggesting early preclinical cardiac involvement in SSc. This impairment in coronary microvasculature is detectable by a non-invasive echocardiographic method and in this study was more common in the diffuse form of SSc.

New non-angiogenesis dependent pathways for tumour growth

The current wisdom is that tumours are endowed with an angiogenic capability and that their growth, invasion and metastasis are angiogenesis-dependent. This article summarises the literature concerning recent histomorphological studies that indicate that some tumours may be vascularised without significant angiogenesis, probably by using existing vessels, a process later described as vascular co-option, or even by forming vascular channels on their own through a non-endothelial cell process called "vascular mimicry". Moreover, the possibility that bone marrow-derived stem cells may also be a source of endothelial precursor cells recruited for tumour-induced neovascularisation, is reviewed. In fact, it has been assumed that the additional endothelial cells required to construct new tumour vessels come from the division and proliferation of local endothelial cells and that endothelial cells incorporated into sites of neovascularisation, including tumour-induced new blood vessels, may be derived from these precursor cells. Finally, lymphoangiogenesis as a mechanism of de novo formation of lymphatics, favouring the metastatic dissemination of tumour cells, is summarised. Potential therapeutic applications are also discussed.

Tumor vascularity and tryptase-positive mast cells correlate with a poor prognosis in melanoma

BACKGROUND

The importance of angiogenesis in melanoma has been controversial and is not homogeneous. Mast cell density (MCD) is highly correlated with the extent of both normal and pathological angiogenesis, such as that in chronic inflammatory diseases and tumours.

METHODS

We evaluated the prognostic significance of tumour microvascular density (MVD) and MCD in 25 advanced melanoma patients after resection and a 4-5-year follow up: 48% of the patients were alive and free of metastases (good prognostic subgroup); 16% had developed regional nodal metastases (intermediate prognostic subgroup); and 36% had died (poor prognostic subgroup). Tissues samples were investigated immunohistochemically to count microvessels and mast cells with an antifactor VIII and an antitryptase antibody, respectively.

RESULTS

Immunohistological staining showed a higher number of microvessels and mast cells in melanoma lesions of poor prognosis as compared with intermediate prognosis and with good prognosis, respectively.

CONCLUSIONS

These data agree with those showing a close relationship between MCD and angiogenesis during tumour progression and demonstrate, for the first time, a prognostic significance of MCD in human melanoma.

Erythropoietin as an angiogenic factor in gastric carcinoma

AIMS

Previous studies have shown that increased vascularity is associated with haematogenous metastasis and poor prognosis in gastric cancer. The role of erythropoietin (Epo) in angiogenesis has not been completely clarified, although its involvement has been reported. In this study we correlated microvascular density and Epo receptor (Epo-R) expression in endothelial and tumour cells with histopathological type in gastric cancer.

METHODS AND RESULTS

Specimens of primary gastric adenocarcinomas obtained from 40 patients who had undergone curative gastrectomy were investigated immunohistochemically by using anti-CD31 and anti-Epo-R antibodies. Stage IV gastric carcinoma had a higher degree of vascularization than other stages, and Epo-R expression in both endothelial and tumour cells increased in parallel with malignancy grade and was highly correlated with the extent of angiogenesis.

CONCLUSIONS

Epo-R level correlates with angiogenesis and progression of patients with gastric carcinoma and we suggest that Epo might have a trophic effect on the vasculature of the gastrointestinal tract. Understanding mechanisms of gastric cancer angiogenesis provides a basis for a rational approach to the development of an anti-angiogenic therapy in patients with gastric cancer.

Neovascularisation, expression of fibroblast growth factor-2, and mast cells with tryptase activity increase simultaneously with pathological progression in human malignant melanoma

Tissues from 92 proliferative lesions of the melanocytic lineage defining distinct steps in tumour progression were investigated immunohistochemically for changes in angiogenesis, expression of fibroblast growth factor-2 (FGF-2) and density of total mast cells (MCs) and MCs expressing tryptase, an angiogenic-inducing molecule. Although the microvessel number was low in common nevi, it increased significantly in nevi with architectural disorder with varying degrees of melanocytic atypia (termed 'nevi with ADMA'), and these changes persisted during tumour development. Progression of primary melanomas was accompanied by a high microvessel number, and the progression to metastases by another significant increase in the microvessel counts. Expression of FGF-2, evaluated as percentages of positive lesions and positive cells per lesion was upregulated in the course of progression. Changes in expression were associated with nevi with ADMA, tumour changeover, penetration of the tumour into the dermis and metastases. A high correlation was demonstrated in all groups of tissues between the microvessel counts, percentages of FGF-2-positive tumour cells, and both total metachromatic and tryptase-reactive MCs. These results suggest that angiogenesis in human melanoma increases with tumour progression and that FGF-2 secreted by tumour cells and tryptase secreted by host MCs cooperate in its induction.

Increased level of HLA-B27 expression in ankylosing spondylitis patients compared with healthy HLA-B27-positive subjects: a possible further susceptibility factor for the development of disease

OBJECTIVE

In B27 transgenic rats, susceptibility to the development of a spondyloarthropathy-like disease has been shown to correlate with the level of B27 transgene expression on lymphoid cells. The aim of this work was to study HLA-B27 molecule expression in peripheral blood mononuclear cells (PBMCs) from patients with ankylosing spondylitis (AS) and from normal controls (NC).

METHODS

Twenty B27(+) AS patients and 16 B27(+) NC were studied. HLA-B27 whole molecules and free heavy chains (HCs) and total HLA class I molecules were evaluated at the surface of PBMCs by immunofluorescence and flow cytometry. B27 subtypes were defined with the PCR-SSP (polymerase chain reaction-sequence-specific primer) technique. Cellular activation was evaluated by the expression of CD69, CD25 molecules and interferon gamma (IFN-gamma) production.

RESULTS

B27 expression was 55,536.3+/-18,961.0 MESF (molecules of equivalent soluble fluorochromes) units in AS and 25,936.0+/-12,117.5 MESF in NC (P=0.00009), total HLA class I expression was 448,840.2+/-136,293.8 MESF in AS and 533,494.4+/-232,931.1 MESF in NC (not significant), HC expression was 10,593.4+/-6,396.1 MESF in AS and 14,843.0+/-7,544.2 MESF in NC (not significant). The higher B27 expression in the SA group was not due to higher cell activation as it was not correlated with CD69 and CD25 expression in PBMCs or with the level of IFN-gamma. HLA-B27 expression did not correlate with indexes of disease status [Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Metrology Index (BASMI)].

CONCLUSIONS

We found greater expression of HLA-B27 molecules in patients with AS than in healthy subjects. This phenomenon was not accompanied by general up-regulation of HLA class I molecules or by greater expression of classical T-cell activation markers. On this basis we propose that the higher expression of the HLA-B27 molecules is a further predisposing factor for the development of AS.

Sustained normalization of cerebral blood-flow after iloprost therapy in a patient with neuropsychiatric systemic lupus erythematosus

We report the case of a 30-year-old caucasian woman affected by SLE who developed neurological symptoms (prosopagnosia and visual-spatial agnosia) after nine years of disease. Brain MRI showed no abnormalities while a brain SPECT scan showed diffuse uptake defects and hypoperfusion areas in the right and left frontal-parietal regions. At that time the patient was on hydroxychloroquine (400 mg/day) and oral prednisolone (0.5 mg/kg/day) as maintenance therapy. One year later the patient showed worsening of Raynaud's phenomenon with digital dystrophic lesions and was therefore treated with an intravenous infusion of Iloprost (1.5 ng/kg/min per 6h/day for 10 days consecutively), while baseline treatment remained unchanged. One month later the patient showed a dramatic improvement in her cognitive function and subsequent SPECT scans showed the gradual disappearance of perfusion abnormalities. This first report of Iloprost treatment in CNS lupus suggests the potential therapeutic usefulness of this drug in patients with SLE and functional CNS involvement.

Correlation of bone marrow angiogenesis and mast cells with tryptase activity in myelodysplastic syndromes

Bone marrow samples from 30 patients with myelodysplastic syndromes (MDS) grouped according to the International Prognostic Scoring System for MDS were investigated for counts of microvessels, total metachromatic mast cells (MC) and MC expressing tryptase, an angiogenesis-inducing molecule. Counts were higher in patients with a poor prognosis. The observation of a high correlation between microvessel counts and both total metachromatic and tryptase-reactive MC in all samples suggests that angiogenesis in MDS increases with their progression and that MC may intervene in the angiogenic response in MDS through tryptase contained in their secretory granules.

Anti-angiogenic activity of the purine analog 6-thioguanine

The antimetabolite 6-thioguanine (6-TG) is utilized in the management of acute myelogenous leukemia (AML). Angiogenesis is a possible therapeutic target in hematologic tumors. Thus, we addressed the possibility that 6-TG may also act as an anti-angiogenic molecule. 6-TG inhibited endothelial cell proliferation triggered by fibroblast growth factor-2 (FGF2) and vascular endothelial growth factor (VEGF) and delayed the repair of a mechanically wounded endothelial cell monolayer. Also, 6-TG inhibited sprouting within fibrin gel, morphogenesis on Matrigel, and collagen gel invasion by endothelial cells. 2-Aminopurine was ineffective. In vivo, 6-TG inhibited basal, VEGF-induced, and FGF2-induced vascularization in the chick embryo chorioallantoic membrane and prevented neovascularization triggered by leukemia LIK cells or their conditioned medium. Finally, bone marrow vascularization in AML patients was decreased to control values in the early remission phase and persisted unvaried after 8-12 months of maintenance therapy with 6-TG. Thus, 6-TG inhibits different steps of the angiogenesis process in vitro and exerts a potent anti-angiogenic activity in vivo. Its anti-angiogenic activity, together with its antimetabolite activity towards tumor cells, may contribute to its action during maintenance therapy in AML. These results suggest a new rationale for the use of purine analogs in the management of AML.

[The role of HLA-B27 molecules in the pathogenesis of ankylosing spondylitis]

Ankylosing Spondylitis (AS) is characterised by the strongest association with an HLA antigen ever described for any disease. It represents therefore the ideal model for the understanding of the link between immune-mediated diseases and the HLA system. The role of HLA-B27 in the pathogenesis of AS will be discussed focusing on the recently described higher expression of these molecules in patients with AS compared with healthy controls.

Multiple myeloma and mycosis fungoides in the same patient: clinical, immunologic, and molecular studies

The coexistence of multiple myeloma (MM) and mycosis fungoides (MF), and hence of both B- and T-cell neoplastic clones, is a rare event. We describe a case of plaque-stage MF associated with IgG lambda MM. The clinical onset of MF preceded that of MM, supporting the hypothesis that MF predisposed to the development of the B-cell proliferative disorder. The skin tumor cells were found to originate from CD4(+) T-lymphocytes, characterized by a V beta 8 receptor and no proviral human T-lymphotropic virus (HTLV)-I monoclonal integration. They also displayed a polarized Th1-type cytokine profile containing mRNAs for interleukin (IL)-2, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-beta, but not for IL-4, IL-5, or IL-10. The CD8(+)/CD57(+) suppressor-cytotoxic subpopulation was significantly increased in the peripheral blood and was associated with MM progression. Expression of p16INK4A, a gene from the INK family that inhibits cyclin-dependent kinases and regulates the cell cycle, was lacking in MF cells and bone marrow (BM) plasma cells. The p16INK4A gene was silenced by hypermethylation, suggesting that it plays a role in the early phase of the pathogenesis of both diseases. Thus, a lymphoid precursor cell presumably contains aberrations that induce the development of both clonal diseases in a multistep process.

Bone marrow angiogenesis and plasma cell angiogenic and invasive potential in patients with active multiple myeloma

Factor VIII-related antigen-positive microvessel areas were measured by both immunohistochemistry and computerized image analysis in patients with active multiple myeloma (MM), nonactive MM and monoclonal gammopathies of undetermined significance (MGUS). A 5- to 6-fold larger area was found in patients with active MM compared to the other two groups. The conditioned medium (CM) of their bone marrow plasma cells stimulated endothelial cell proliferation and chemotaxis, monocyte chemotaxis and angiogenesis in vivo [chick embryo chorioallantoic membrane (CAM) system] more strongly and frequently than the CM of patients with nonactive MM and MGUS. An immunoassay of plasma cell lysates gave significantly higher levels of fibroblast growth factor-2 (FGF-2) in patients with active MM than in the other two groups, and a neutralizing anti-FGF-2 antibody inhibited by 54-68% the biological activity exerted by the CM in vitro and in the CAM. In situ hybridization of bone marrow plasma cells and gelatin zymography of CM showed that patients with active MM express higher levels of matrix metalloproteinase-2 (MMP-2) mRNA and protein than those with nonactive MM and MGUS, whereas MMP-9 expression and secretion overlapped in all groups. Overall data suggest that patients with active MM represent the vascular phase of plasma cell tumors that is triggered by bone marrow plasma cells, at least partly, through FGF-2 and MMP-2. Both angiogenesis and MMP-2 secretion can account for intramedullary and extramedullary spreading of plasma cells during the active MM.

Role of hematopoietic growth factors in angiogenesis

In early ontogeny, hematopoiesis is closely associated with angiogenesis. This article reviews recent studies of the effect of hematopoietic growth factors on several endothelial cell functions together with recent findings about angiogenesis and antiangiogenic therapies in hematopoietic malignancies such as leukemia, lymphoma and myeloma.

Angiogenesis and anti-angiogenesis in neuroblastoma

Angiogenesis is a biological process by which new capillaries are formed from pre-existing vessels. It occurs in physiological and pathological conditions, such as tumours, where a specific critical turning point is the transition from the avascular to the vascular phase. Tumour angiogenesis depends mainly on the release by neoplastic cells of growth factors specific for endothelial cells that able to stimulate the growth of the host's blood vessels. This review summarises the literature concerning the relationship between angiogenesis and progression in human neuroblastoma, the most common extracranial solid tumour of infancy and childhood. It is becoming increasingly evident that agents which interfere with blood vessel formation also block tumour progression. Accordingly, anti-angiogenic tumour therapy has gained much interest in preclinical and clinical assessments. The recent applications of anti-angiogenic agents which interfere or block neuroblastoma progression are reviewed.

Inhibition of endothelial cell functions and of angiogenesis by the metastasis inhibitor NAMI-A

NAMI-A is a ruthenium-based compound with selective anti-metastasis activity in experimental models of solid tumours. We studied whether this activity was dependent on anti-angiogenic ability of NAMI-A. We thus investigated its in vitro effects on endothelial cell functions necessary for angiogenesis to develop, as well as its in vivo effects in the chick embryo chorioallantoic membrane model. Endothelial cell proliferation, chemotaxis, and secretion of the matrix-degrading enzyme metalloproteinase-2 were inhibited by NAMI-A in a dose-dependent manner, and without morphologic signs of cell apoptosis or necrosis. Lastly, NAMI-A displayed a dose-dependent in vivo anti-angiogenic activity in the chorioallantoic membrane model. These data suggest that the anti-angiogenic activity of NAMI-A can contribute to its anti-metastatic efficacy in mice bearing malignant solid tumours.

Angiogenesis extent and expression of matrix metalloproteinase-2 and -9 agree with progression of ovarian endometriomas

BACKGROUND

Changes in angiogenesis and expression of extracellular matrix-degrading enzymes have been substantiated in tumour changeover and progression.

METHODS

Tissues from 44 biopsies of stage III and IV ovarian endometriomas, and 10 biopsies of normal (control) endometrium were investigated immunohistochemically to count microvessels, and by in situ hybridization to assess the expression of mRNA of matrix metalloproteinase-2 (MMP-2) and MMP-9. Implants of the tissues were investigated in the chick embryo chorioallantoic membrane (CAM) assay to determine their angiogenic capacity.

RESULTS

The endometriomas displayed significantly higher counts than normal endometria and the highest values were associated with the deepest invasion level (stage IV). Microvessels localized in close association with ectopic endometrial cells in the form of winding and arborized tubes, often dilated in microaneurysmatic segments. These were absent in normal endometrium. Expression of MMP-2 and MMP-9 mRNA, evaluated as percentages of positive biopsies and intensity of expression, was up-regulated in endometriomas and more pronounced in stage IV. MMP-2 and MMP-9 mRNA were also expressed by host stromal cells, including microvascular endothelial cells, fibroblasts and macrophages, whereas the control endometrium showed very little expression of MMP-2 mRNA in a few endothelial cells and no expression of MMP-9 mRNA. Implants from stage IV endometrioma induced a more intense vasoproliferative response than those from stage III, while no vasoproliferative response was induced by the normal endometrium.

CONCLUSION

These data suggest that angiogenesis and degradation of extracellular matrix occur together in endometriosis and are more pronounced in stage IV, and that endometriosis cells and some host stromal cell populations co-operate in disease progression.

Mast cells and their secretory granules are angiogenic in the chick embryo chorioallantoic membrane

BACKGROUND

Many data suggest that the density of mast cells is highly correlated with the extent of both normal and pathological angiogenesis.

OBJECTIVE

In this study we have compared in an in vivo assay, the chick embryo chorioallantoic membrane, the angiogenic potential of mast cell suspensions isolated from rats, degranulated mast cells and their secretory granules.

METHODS

Gelatin sponges adsorbed with cell suspensions of rat mast cells, degranulated mast cells and their secretory granules were implanted on the top of the chorioallantoic membrane at day 8 of incubation. At day 12 the angiogenic response was evaluated macroscopically, microscopically and by a morphometric method of 'point counting'.

RESULTS

Isolated mast cells and their secretory granules, but not degranulated mast cells, induced an angiogenic response in the chorioallantoic membrane. The addition of antifibroblast growth factor-2 or antivascular endothelial growth factor antibodies reduced the angiogenic response of both mast cells and their secretory granules by 50% and 30%, respectively.

CONCLUSION

These data support the evidence that the angiogenic properties of mast cells depend on the angiogenic molecules contained in their secretory granules and indicate that fibroblast growth factor-2 and vascular endothelial growth factor are the angiogenic cytokines primarily and perhaps synergistically responsible for this vasoproliferative activity.