Significance of angiogenin plasma concentrations in patients with acute myeloid leukaemia and advanced myelodysplastic syndrome

Angiogenic Molecules in Hodgkin's Disease: Results from Sequential Serum Analysis

Increased angiogenic activity has been demonstrated in lymphoproliferative diseases including Hodgkin's disease. In the current study, the levels of circulating angiogenic molecules in 60 Hodgkin's patients were determined prior to and after treatment and correlated to disease stage and prognostic score. Hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were increased in Hodgkin's patients in comparison to healthy controls (p<0.001). Angiogenin and angiopoietin-2 levels did not differ from controls. HGF, VEGF, TNF-α and angiogenin decreased significantly in Hodgkin's patients after standard treatment (p<0.001 for HGF, p<0.05 for VEGF, TNF-α and angiogenin). Furthermore, HGF and TNF-α increased with advancing stage of disease (p<0.05). HGF and VEGF correlated significantly with IL-6 (r=0.56, p<0.0005 and r=0.57, p<0.001 respectively). In conclusion, Hodgkin's disease displays an angiogenic activity as depicted by the increased serum levels of a number of angiogenic cytokines. HGF seems to be the prominent molecule in Hodgkin's disease, which may be used to monitor the disease status and the response to treatment.

Ribonuclease 5 facilitates corneal endothelial wound healing via activation of PI3-kinase/Akt pathway

To maintain corneal transparency, corneal endothelial cells (CECs) exert a pump function against aqueous inflow. However, human CECs are arrested in the G₁-phase and non-proliferative in vivo. Thus, treatment of corneal endothelial decompensation is limited to corneal transplantation, and grafts are vulnerable to immune rejection. Here, we show that ribonuclease (RNase) 5 is more highly expressed in normal human CECs compared to decompensated tissues. Furthermore, RNase 5 up-regulated survival of CECs and accelerated corneal endothelial wound healing in an in vitro wound of human CECs and an in vivo cryo-damaged rabbit model. RNase 5 treatment rapidly induced accumulation of cytoplasmic RNase 5 into the nucleus, and activated PI3-kinase/Akt pathway in human CECs. Moreover, inhibition of nuclear translocation of RNase 5 using neomycin reversed RNase 5-induced Akt activation. As a potential strategy for proliferation enhancement, RNase 5 increased the population of 5-bromo-2′-deoxyuridine (BrdU)-incorporated proliferating CECs with concomitant PI3-kinase/Akt activation, especially in CECs deprived of contact-inhibition. Specifically, RNase 5 suppressed p27 and up-regulated cyclin D1, D3, and E by activating PI3-kinase/Akt in CECs to initiate cell cycle progression. Together, our data indicate that RNase 5 facilitates corneal endothelial wound healing, and identify RNase 5 as a novel target for therapeutic exploitation.

Vascular disruption and the role of angiogenic proteins after spinal cord injury

Spinal cord injuries (SCI) can result in devastating paralysis, for which there is currently no robustly efficacious neuroprotective/neuroregenerative treatment. When the spinal cord is subjected to a traumatic injury, the local vasculature is disrupted and the blood–spinal cord barrier is compromised. Subsequent inflammation and ischemia may then contribute to further secondary damage, exacerbating neurological deficits. Therefore, understanding the vascular response to SCI and the molecular elements that regulate angiogenesis has considerable relevance from a therapeutic standpoint. In this paper, we review the nature of vascular damage after traumatic SCI and what is known about the role that angiogenic proteins—angiopoietin 1 (Ang1), angiopoietin 2 (Ang2) and angiogenin—may play in the subsequent response. To this, we add recent work that we have conducted in measuring these proteins in the cerebrospinal fluid (CSF) and serum after acute SCI in human patients. Intrathecal catheters were installed in 15 acute SCI patients within 48 h of injury. CSF and serum samples were collected over the following 3–5 days and analysed for Ang1, Ang2 and angiogenin protein levels using a standard ELISA technique. This represents the first description of the endogenous expression of these proteins in an acute human SCI setting.

High serum angiogenin at diagnosis predicts for failure on long-term treatment response and for poor overall survival in non-Hodgkin lymphoma

BACKGROUND

Angiogenin is a potent inducer of angiogenesis. We prospectively evaluated the prognostic significance of serum angiogenin from 204 consecutive non-Hodgkin lymphoma (NHL) patients diagnosed and treated in a single institution.

METHODS

Serum angiogenin, VEGF, and bFGF concentrations at diagnosis were determined using a quantitative sandwich enzyme immunoassay technique. Kaplan-Meier survival curves were compared by the log-rank test. Multivariate survival analyses were performed using the parametric model of Weibull and the non-parametric proportional hazards model of Cox.

RESULTS

Patients with a high serum angiogenin at diagnosis (>median; 401 ng/ml) had significantly lower 5-year survival rate than those with a low (≤ median) angiogenin (42% versus 63%, respectively; P = 0.0073). Serum angiogenin provided additional information to the International Prognostic Index (IPI) identifying a subgroup (serum angiogenin >median and IPI>1) with very poor prognosis (5-year survival 19%, P < 0.0001). In receiver operating characteristic (ROC) analyses the accuracy of the IPI to correctly classify patients with favourable or poor survival was improved from fair to good by complementing the IPI with serum angiogenin concentration. With patients who initially achieved complete response (CR) after chemotherapy, a high angiogenin at diagnosis (>median; relative risk (RR) 2.38; P = 0.0077) and an advanced tumour stage (III-IV; RR 2.41; P = 0.0087) were the only independent predictors for patients with unfavourable outcome although first responding well to therapy.

CONCLUSIONS

We conclude that elevated serum angiogenin surfaced as an independent predictor for failure in long-term treatment response and for poor overall survival in a series of 204 NHL patients, and might thus also complement the IPI in identifying the patients with particularly aggressive and/or treatment resistant disease.

Microarray analysis of somatostatin receptor 5-regulated gene expression profiles in murine pancreas

BACKGROUND

We previously demonstrated that somatostatin receptor type 5 (SSTR5) gene ablation results in alterations in insulin secretion and glucose metabolism, accompanied by morphologic alterations in the islets of Langerhans. The underlying mechanism(s) by which SSTR5 exerts its cellular functions remain(s) unknown. We hypothesized that SSTR5 mediates the inhibitory effect of somatostatin (SST) on insulin secretion and islet proliferation by regulating a specific set of pancreatic genes.

METHODS

To identify SSTR5-regulated pancreatic genes, gene expression microarray analysis was performed on the whole pancreas of 1- and 3-month-old wild-type (WT) and SSTR5 knockout (SSTR5-/-) male mice. Real-time RT-PCR and immunofluorescence were performed to validate selected differentially expressed genes.

RESULTS

A set of 143 probes were identified to be differentially expressed in the pancreas of 1-month-old SSTR5-/- mice, 72 of which were downregulated and 71 upregulated. At 3 months of age, SSTR5 gene ablation resulted in downregulation of a set of 30 probes and upregulation of a set of 37 probes. Among these differentially expressed genes, there were 15 and 5 genes that were upregulated and downregulated, respectively, in mice at both 1 and 3 months of age. Three genes, PAP/INGAP, ANG, and TDE1, were selected to be validated by real-time RT-PCR and immunofluorescence.

CONCLUSIONS

A specific set of genes linked to a wide range of cellular functions such as islet proliferation, apoptosis, angiogenesis, and tumorigenesis were either upregulated or downregulated in SSTR5-deficient male mice compared with their expression in wild-type mice. Therefore, these genes are potential SSTR5-regulated genes during normal pancreatic development and functional maintenance.

Immunohistochemical detection of vascular endothelial growth factor (VEGF) in the bone marrow in patients with myelodysplastic syndromes: correlation between VEGF expression and the FAB category

Recent data suggest that vascular endothelial growth factor (VEGF) is produced in neoplastic cells in various myeloid neoplasms and plays a key role as an autocrine regulator and mediator of angiogenesis. We examined the expression of VEGF in paraffin-embedded bone marrow sections obtained from normal donors (n = 5) and 46 patients with myelodysplastic syndromes [MDS, French-American-British (FAB)-type refractory anemia (RA), n = 10; refractory anemia with ringed sideroblasts (RARS), n = 10; refractory anemia with excess blasts (RAEB), n = 10; RAEB in transformation (RAEB-T), n = 8; chronic myelomonocytic leukemia (CMML), n = 8] by immunohistochemistry using an anti-VEGF antibody. In normal bone marrow, the anti-VEGF antibody was found to react with myeloid progenitor cells, immature monocytic cells, plasma cells and megakaryocytes, but not with erythroid cells or mature granulocytic cells. Higher levels of VEGF were found in patients with MDS, subtypes RAEB, RAEB-T and CMML, compared to patients with RA or RARS, or the normal bone marrow. These differences were found to result from expression of VEGF in immature myeloid cells in RAEB, RAEB-T and CMML. The microvessel density was also higher in patients with RAEB-T and CMML compared to RA and RARS or the normal bone marrow. Expression of VEGF mRNA was demonstrable in isolated neoplastic cells by reverse transcriptase-polymerase chain reaction in all patients examined. In aggregate, these data show that VEGF is expressed in bone marrow cells in patients with MDS. The amount of expressed VEGF is related to the percentage of immature myeloid cells (blasts and monocytic progenitors) and correlates with the FAB category.

A new terrein glucoside, a novel inhibitor of angiogenin secretion in tumor angiogenesis

Angiogenesis is a critical step for the tumor therapy. Many angiogenic factors are involved in the tumor angiogenesis. In the course of our screening for inhibitors of angiogenin secretion, one of angiogenic factors, we have isolated a new terrein glucoside (1) and terrein (2) from the fermentation broth of fungal strain Aspergillus sp. PF1381. The structure and absolute stereochemistry of 1 was determined to be (4S,5R)-5-[(alpha-D-glucopyranosyl)oxy]-4-hydroxy-3-(E-1-propenyl)-2-cyclopenten-1-one on the basis of spectral and enzymatic analyses. Compounds 1 and 2 equally inhibited angiogenin secretion from androgen-dependent prostate cancer cells, LNCaP-CR, with IC50 values of 13 microM. However, both compounds did not affect VEGF secretion, another angiogenic factor. Furthermore, both compounds inhibited tube formation of human umbilical vein endothelial cells (HUVEC). These results suggested that 1 and 2 act as angiogenesis inhibitors through the inhibition of angiogenin secretion.

Angiogenesis-related growth factors and cytokines in the serum of patients with B non-Hodgkin lymphoma; relation to clinical features and response to treatment

Increased angiogenesis has been shown to be a feature of non-Hodgkin lymphomas (NHL). In the current study, the pretreatment levels of circulating molecules related to angiogenesis were determined in 49 B-cell NHL patients and correlated with histological grade, disease stage and prognostic score. In 25 patients, the same molecules were defined after standard treatment. Vascular endothelial growth factor (VEGF), angiogenin, interleukin-2 (IL-2), IL-6, IL-8 and IL-16 were measured. Increased levels of VEGF, IL-6 and IL-8 were found in the whole group of untreated patients in comparison with normal controls (P < 0.05), whereas, IL-2 was higher in the subgroup of indolent NHL. Overall, there was no significant decrease in the levels of these molecules after treatment. However, by stratification into group of responders vs. non-responders pretreatment IL-8 was significantly increased whereas IL-16 was decreased in the subgroup of complete responders. According to the REAL classification IL-2 was higher in the low risk compared with intermediate plus high-risk group. There was no association with disease stage or the International Prognostic Score. Both indolent and aggressive B cell lymphomas have increased production of angiogenic mediators and cytokines with IL-8 and IL-16 potentially reflecting the response to treatment.

Tumour necrosis factor-induced gene expression in human marrow stroma: clues to the pathophysiology of MDS?

Aberrant regulation of the tumour necrosis factor alpha gene (TNF) and stroma-derived signals are involved in the pathophysiology of myelodysplasia. Therefore, KG1a, a myeloid leukaemia cell line, was exposed to Tnf in the absence or presence of either HS-5 or HS-27a cells, two human stroma cell lines. While KG1a cells were resistant to Tnf-induced apoptosis in the absence of stroma cells, Tnf-promoted apoptosis of KG1a cells in co-culture experiments with stroma cells. To investigate the Tnf-induced signals from the stroma cells, we examined expression changes in HS-5 and HS-27a cells after Tnf exposure. DNA microarray studies found both discordant and concordant Tnf-induced expression responses in the two stroma cell lines. Tnf promoted an increased mRNA expression of pro-inflammatory cytokines [e.g. interleukin (IL)6, IL8 and IL32]. At the same time, Tnf decreased the mRNA expression of anti-apoptotic genes (e.g. BCL2L1) and increased the mRNA expression of pro-apoptotic genes (e.g. BID). Overall, the results suggested that Tnf induced a complex set of pro-inflammatory and pro-apoptotic signals in stroma cells that promote apoptosis in malignant myeloid clones. Additional studies will be required to determine which of these signals are critical for the induction of apoptosis in the malignant clones. Those insights, in turn, may point the way to novel therapeutic approaches.

Serum angiogenin levels predict treatment response in patients with stage IV melanoma

This work was conducted to find out new potential serum markers and study their role as predictive factors in patients with metastatic melanoma. Serum samples from 68 patients with stage IV malignant melanoma were collected just before current treatment and screened for 79 different cytokines by using a multi-cytokine array. Angiogenin, which is a protein capable of promoting angiogenesis, was found to be markedly elevated among a sub-group of patients with progressive disease (PD) and thus was subjected to further analysis. The mean serum angiogenin level was 270 ng/ml and the median 236 ng/ml (STD 163 ng/ml). Concentrations were significantly higher among men than in women (P = 0.031), whereas patient's age, site of the primary tumour, Clark's or Breslow's classifications were not associated with angiogenin levels. Patients with only lymph node metastases had markedly lower angiogenin levels than those with metastases at other sites (P = 0.05). High angiogenin levels were significantly (P = 0.015; Kruskal-Wallis) associated with poor treatment response with chemoimmunotherapy. Treatment-related survival (TRS) was shorter (10 months) in patients with above-median values than in those with below-median levels (19 months, P = NS). Cox multivariate regression model was used to control for the confounding by the classical prognostic factors of melanoma (age, sex, disease burden, performance score, site of metastases). Disease burden was the only variable that remained in the model as a significant independent predictor of TRS (P = 0.044). These data suggest that serum angiogenin levels might be of predictive value in the evaluation of treatment response for patients with stage IV melanoma.

A therapeutic target for prostate cancer based on angiogenin-stimulated angiogenesis and cancer cell proliferation

Human angiogenin is progressively up-regulated in the prostate epithelial cells during the development of prostate cancer from prostate intraepithelial neoplasia (PIN) to invasive adenocarcinoma. Mouse angiogenin is the most up-regulated gene in AKT-induced PIN in prostate-restricted AKT transgenic mice. These results prompted us to study the role that angiogenin plays in prostate cancer. Here, we report that, in addition to its well established role in mediating angiogenesis, angiogenin also directly stimulates prostate cancer cell proliferation. Angiogenin undergoes nuclear translocation in PC-3 human prostate cancer cells grown both in vitro and in mice. Thus, knocking down angiogenin expression in PC-3 human prostate adenocarcinoma cells inhibits ribosomal RNA transcription, in vitro cell proliferation, colony formation in soft agar, and xenograft growth in athymic mice. Blockade of nuclear translocation of angiogenin by the aminoglycoside antibiotic neomycin inhibited PC-3 cell tumor growth in athymic mice and was accompanied by a decrease in both cancer cell proliferation and angiogenesis. These results suggest that angiogenin has a dual effect, angiogenesis and cancer cell proliferation, in prostate cancer and may serve as a molecular target for drug development. Blocking nuclear translocation of angiogenin could have a combined benefit of antiangiogenesis and chemotherapy in treating prostate cancer.

Angiogenin: a review of the pathophysiology and potential clinical applications

Angiogenin is a member of the ribonuclease (RNase) superfamily: enzymes of innate substrate specificity, but divergent functional capacities. Angiogenin is a normal constituent of the circulation and contained in a vasculature that rarely undergoes proliferation, but in some physiological and pathological conditions its levels increase in blood, promoting neovascularization. Hence, angiogenesis is a common pathophysiological attribute of angiogenin. In malignant disease, the most studied pathological state in regard to angionenin, abnormally high levels are seen, which may be of prognostic significance. Angiogenin has also been studied in other non-malignant pathological states. The aim of this review article is to provide an overview of the biochemistry and physiology of angiogenin, specifically in relation to the human pathological states where angiogenin has been implicated and finally, its potential clinical applications.

Genetic and environmental determinants of circulating levels of angiogenin in community-based sample

BACKGROUND

Measurement of angiogenin in plasma provides important prognostic and diagnostic information in variety of malignancies and may even correlate with cancer's progression. Nevertheless, nowadays, specific physiological mechanisms of this protein action as well as major factors regulating its circulating levels normally and in pathology are still poorly understood. The main objectives of this study were to examine the contribution of a number of endogenous factors, such as sex, age, body size and genetic effects on the production of angiogenin in apparently healthy individuals, and to assess the correlations in circulating levels between angiogenin and other molecules involved in angiogenesis.

METHODS

The plasma levels of angiogenin and each of the additional cytokines [interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), macrophage-colony stimulating factor (M-CSF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), soluble intercellular adhesion molecule-1 (sICAM)] were determined by enzyme-linked immunoassay in a large family based sample.

RESULTS

Angiogenin levels were significantly higher in man than in women (360.64 +/- 104.04 ng/ml vs. 322.15 +/- 100.34 ng/ml, P < 0.01) and significantly correlated with age (P < 0.01) in both sexes. Genetic analysis showed that adjusted for potential covariates, 37.4 +/- 7.1% of angiogenin variation was attributable to putative genetic factors. The results of our study revealed that angiogenin concentrations were positively and significantly (P < 0.05) associated with sICAM, IL-6, TNF-alpha and M-CSF levels in the female cohort.

CONCLUSIONS

Our data provide reliable evidence for the substantial role of genetic factors in the determination of the phenotypic variability of angiogenin plasma levels. These findings of our study, including circulating angiogenin reference limits in healthy population and its correlation with angiogenic cytokines, may be of importance in determination of early stages of pathological angiogenesis.

Thalidomide therapy in adult patients with myelodysplastic syndrome

BACKGROUND

Thalidomide has shown promise for the treatment of patients with myelodysplastic syndrome. The current prospective multicenter study examined the efficacy and toxicity of thalidomide in adult patients with myelodysplastic syndrome.

METHODS

Using the International Prognostic Scoring System (IPSS), patients were stratified into 2 groups: favorable (IPSS score, 0-1.0) or unfavorable (IPSS score, 1.5-3.5). Seventy-two patients (42 of whom were favorable and 30 of whom were unfavorable) received a starting dose of oral thalidomide of 200 mg daily. The dose was increased by 50 mg per week to a targeted maximum daily dose of 1000 mg.

RESULTS

According to the International Working Group response criteria for myelodysplastic syndrome, 1 patient in the unfavorable group achieved a partial remission with a complete cytogenetic response. Overall, 2 patients (5%) in the favorable group and 4 patients (14%) in the unfavorable group experienced either a hematologic improvement or a partial response. The most frequent Grade 3 or 4 (grading was based on the National Cancer Institute's Common Toxicity Criteria [version 2.0]) nonhematologic adverse events were fatigue (24%), infection (19%), neuropathy (13%), dyspnea (8%), and constipation (7%).

CONCLUSIONS

Thalidomide alone, at the schedule and dose levels used in the current study, is not a safe and viable therapeutic option for patients with myelodysplastic syndrome. Limited efficacy and increased toxicity were observed in the current Phase II trial.

Having a higher blast percentage in circulation than bone marrow: clinical implications in myelodysplastic syndrome and acute lymphoid and myeloid leukemias

Determining the percentage of peripheral blood (PB) and bone marrow (BM) blasts is important for diagnosing and classifying acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Although most patients with acute leukemia or MDS have a higher percentage of BM blasts than PB blasts, the relative proportion is reversed in some patients. We explored the clinical relevance of this phenomenon in MDS (n = 446), AML (n = 1314), and acute lymphoblastic leukemia (ALL) (n = 385). Among patients with MDS or ALL, but not AML, having a higher blast percentage in PB than in BM was associated with significantly shorter survival. In multivariate analyses, these associations were independent of other relevant predictors, including cytogenetic status. Our findings suggest that MDS and ALL patients who have a higher percentage of PB blasts than BM blasts have more aggressive disease. These data also suggest that MDS classification schemes should take into account the percentage of blasts in PB differently from the percentage of blasts in BM.

Increased CD133 expression in bone marrow of myelodysplastic syndromes

Fresh frozen bone marrow biopsies were evaluated immunohistochemically, applying monoclonal antibodies against CD31, CD34, VEGFR-2 and CD133, a novel marker identifying human endothelial progenitor cells (EPCs). Specimens of 51 patients diagnosed with MDS were compared with 16 AML and 18 controls. The percentage of CD34 expressing cells was increased and CD31 expression was decreased in advanced stages of MDS compared with normal BM. VEGFR-2 expression was also raised in MDS. Here we show for the first time that increased numbers of CD133 positive cells are present in the majority of MDS patients. Additionally, those cells occasionally seem to contribute to capillary forming units in bone marrow.

Angiogenin is translocated to the nucleus of HeLa cells and is involved in ribosomal RNA transcription and cell proliferation

Angiogenin is an angiogenic protein known to play a role in rRNA transcription in endothelial cells. Nuclear translocation of angiogenin in endothelial cells decreases as cell density increases and ceases when cells are confluent. Here we report that angiogenin is constantly translocated to the nucleus of HeLa cells in a cell density-independent manner. Down-regulation of angiogenin expression by antisense and RNA interference results in a decrease in rRNA transcription, ribosome biogenesis, proliferation, and tumorigenesis both in vitro and in vivo. Exogenous angiogenin rescues the cells from antisense and RNA interference inhibition. The results showed that angiogenin is constitutively translocated into the nucleus of HeLa cells where it stimulates rRNA transcription. Thus, besides its angiogenic activity, angiogenin also plays a role in cancer cell proliferation.

Comparison of cytokeratin 20 RNA and angiogenin in voided urine samples as diagnostic tools for bladder carcinoma

BACKGROUND

We evaluated the diagnostic efficacy of urinary angiogenin (ANG) and cytokeratin 20 (CK-20) mRNA in comparison with voided urine cytology in the detection of bladder cancer patients.

OBJECTIVES AND METHODS

A total of 97 Egyptian patients provided a single voided urine sample for ANG, CK-20 and cytology before cystoscopy. Of the 97 cases, 63 were histologically diagnosed as bladder cancer; 33 with transitional cell carcinoma (TCC) and 30 with squamous cell carcinoma (SCC), whereas the remaining 34 had benign urological disorders. A group of 46 healthy volunteers were also included in this study. Voided urine was centrifuged and the supernatant was used for estimation of ANG by EIA and confirmed by Western blotting (WB). The urine sediment was used for cytology and RNA extraction. CK-20 RNA was detected by RT-PCR.

RESULTS

The best cutoff value for ANG was calculated by a ROC curve as 322.7 ng/mg protein. The median urinary ANG level in bladder carcinoma, benign urological disorders and healthy volunteer groups was: 802.7, 425 and 33 pg/mg protein, respectively. The positivity rate for urinary CK-20 mRNA of the control, benign and malignant groups was 0%, 2.9% and 82.3%, respectively (P = 0.000); while the rates for ANG were 11.6%, 54.8% and 75.4%, respectively (P = 0.000). There was no significant difference in positivity rates of CK-20 and ANG with respect to sex, smoking, schistosomiasis, urine cytology, tumor grade, tumor stage, hematuria or pus cells. The overall sensitivity and specificity were 71.4% and 90% for voided urine cytology, 75.4% and 70.3% for ANG, and 82.3% and 98.8% for CK-20. Combined sensitivity of voided urine cytology with ANG and CK-20 together (98.2%) was higher than either the combined sensitivity of voided urine cytology with ANG (96.5%) or with CK-20 (91.6%) or than that of the biomarker alone. We demonstrated significant positive correlation between CK-20 positivity with age (P = 0.043) and nodal involvement (P = 0.037); however, there was no significant correlation between CK-20 and ANG with the other clinicopathological parameters.

CONCLUSIONS

Our data indicate that CK-20 and ANG in voided urine had higher sensitivities compared to voided urine cytology. However, when specificity was considered, CK-20 alone had superior sensitivity and specificity compared to ANG and voided urine cytology.

Relation between bone marrow angiogenesis and serum levels of angiogenin in patients with myelodysplastic syndromes

Angiogenesis is implicated in the progression of myelodysplastic syndromes (MDS). Bone marrow microvascular density (MVD), serum angiogenin (ANG) and interleukin 6 (IL-6) were measured in 67 patients with untreated MDS. MVD, ANG and IL-6 were significantly higher in the patient group as a whole when compared to controls (P < 0.01). MVD and ANG were significantly higher in subtypes with a high-risk for leukemic transformation (RAEB, RAEB-t and CMML) than in low-risk subtypes (RA and RARS) (P < 0.01). In the MDS group, a positive correlation was found between ANG and IL-6 (P < 0.001) and also between MVD and IL-6 (P < 0.05). Using multivariate analysis, only IL-6 displayed independent prognostic value and was inversely related to MDS survival.

Clinical relevance of circulating angiogenic factors in patients with non-Hodgkin's lymphoma or Hodgkin's lymphoma

Vascular endothelial growth factor (VEGF), basic-fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), and angiogenin are important angiogenic factors. In 65 patients with non-Hodgkin's lymphoma (NHL), pre-treatment VEGF, bFGF, and HGF levels were significantly elevated compared to normal individuals, while angiogenin levels were significantly subnormal. In 37 patients with Hodgkin's disease, pre-treatment levels of VEGF and HGF were significantly elevated, bFGF levels were normal, and angiogenin levels were significantly subnormal. In patients with NHL, post-therapy levels of angiogenin were independently predictive of survival. Both pre-therapy and post-therapy VEGF levels were independently predictive of survival in patients with HD.

Adult acute myeloid leukaemia

The curability of acute myeloid leukaemia (AML) in a fraction of adult patients was demonstrated a long time ago. Currently, the probability of cure is consistently above fifty per cent in patients with de novo disease expressing favourable-risk associated cytogenetic features. Even better, the cure rate exceeds 75% in the acute promyelocytic subtype since the introduction of retinoic acid-containing regimens. In the meantime, continuing progress in supportive care systems and stem cell transplant procedures is making myeloablative therapies, when needed, somewhat less toxic-and thereby more effective-than in the recent past. Therefore, evidence is accumulating to indicate an improved therapeutic trend over the years, with the notable exception of older (>55 years) patients with adverse-risk chromosomal aberrations and/or leukemia secondary to myelodysplasia or prior cancer-related chemotherapy and/or radiotherapy. This review conveys the many facets of this progress, focusing on diagnostic subsets, risk classes, newer biological issues and conventional as well as innovative therapeutic interventions with or without autologous/allogeneic stem cell transplantation.

Serum angiogenin is not elevated in patients with early B-cell chronic lymphocytic leukemia but is prognostic factor for disease progression

The association between angiogenin and cancer progression and poor outcome in solid tumors has been documented, but its significance in leukemias has not been evaluated. Using an ELISA technique (Quantikine Human Angiogenin Immunoassay; R&D Systems), we measured serum angiogenin levels in 77 previously untreated Binet stage A B-cell chronic lymphocytic leukemia (CLL) patients. No difference in angiogenin serum levels could be found between patients (median: 295 ng/mL; range: 74-1700) and 15 age- and sex-matched healthy controls (median: 264 ng/mL; range: 29-1835) (P = NS; Mann-Whitney test). Increased angiogenin serum level was associated with higher LDH (P = 0.03) and beta2-m (P = 0.007) concentrations. However, angiogenin did not reflect the extent of bone marrow (BM) angiogenesis as evaluated by microvessel area (P = 0.611), circulating levels of vascular endothelial growth factor (VEGF) (P = 0.873) and basic fibroblastic growth factor (FGF-2) (P = 0.421). When the 25 patients with available data were stratified into the four major cytogenetic categories (normal karyotype, 13q as a sole aberration, 12q trisomy, 11q or 17p deletion) and aberrations were compared with angiogenin serum levels, no correlation was found (P = 0.651; Kruskall-Wallis test). A cut-off of angiogenin serum level corresponding to median (i.e. 330 ng/mL) or higher identified later upstaging and longer progression-free survival (PFS). The 5-yr PFS was 51.5% for patients with angiogenin levels lower than median and 85% for patients with higher values [P = 0.03; hazard ratio (HR) = 2.86; 95% CI: 1.08-6.72]. Although in multivariate analysis only Rai substages (P = 0.00001) and peripheral blood lymphocytosis (P = 0.009) retained their prognostic significance, angiogenin could be incorporated into the Rai substages thus leading to the identification of the following risk categories: (i) stage 0 (angionenin >330 ng/mL); (ii) stage 0 (angiogenin <330 ng/mL) + stage I-II (angiogenin >330 ng/mL); and (iii) stage I-II (angiogenin <330 ng/mL). The 40-month PFS were as follows: 85%, 65%, 25% (chi(2) for trend = 6.33; d.f. = 1; P = 0.01). In conclusion, serum angiogenin levels although not increased in comparison with healthy controls, may predict clinical outcome of patients with early CLL and help to refine Rai's stratification.

Pathogenesis, classification, and treatment of myelodysplastic syndromes (MDS)

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal myeloid disorders characterized by morphologic dysplasia in one or more cell lineages. Dysplasia in MDS is associated with insufficient production of blood cells and consecutive cytopenia(s). The natural course and prognosis of MDS vary among patients and depend on genetic defects that occur during clonal evolution. In a significant group of patients (roughly 30%) progression to secondary leukemia is observed. These patients appear to have a grave prognosis. The treatment of patients with MDS has to be adjusted to the individual situation and age in each case. In many patients, control of blast cell production by palliative cytoreduction, continuous support with red blood cells, as well as other supportive measures, seem appropriate. In other patients, however, curative therapy (chemotherapy, stem cell transplantation) should be considered. The final decision to offer curative therapy must be based on many different factors including age and the overall situation of the patient. Recently established scoring systems aimed at predicting survival and evolution of leukemia in MDS may be helpful in this regard.

Angiogenesis in hematologic malignancies

Angiogenesis is defined as the formation of new capillaries from preexisting blood vessels and plays an important role in the progression of solid tumors. Recently a similar relationship has been described in several hematologic malignancies. Expression of the angiogenic peptides vascular endothelial growth factor (VEGF) and basic fibroblast growth factor correlates with clinical characteristics in leukemia and non-Hodgkin's-lymphoma and the serum/plasma concentrations serve as predictors of poor prognosis. Increased bone marrow microvessels in multiple myeloma (MM) are correlated with decreased overall survival. Thalidomide which has antiangiogenic effects and direct cytotoxic effects was found to be effective in MM, myelodysplastic syndrome and acute myeloid leukemia (AML). Preliminary data indicate activity of VEGF-tyrosine kinase inhibitors in AML. Clinical research is now aimed at testing antiangiogenic treatment strategies in several hematologic neoplasms as well as identifying the best candidate patients for specific approaches.

Vascularity, angiogenesis and angiogenic factors in leukemias and myelodysplastic syndromes

Bone marrow microenvironment plays a crucial role inthe leukemogenic process. New studies suggest that the bone marrow vascularity changes significantly in the leukemic process and that angiogenic factors play a major role in leukemia and myelodysplasia. However, hematologic malignancies appear to be particularly vulnerable to the effects of angiogenic factors because most of these factors appear to be secreted by hematopoietic cells, and they may have autocrine and paracrine regulatory effects on the hematopoietic system. The use of angiogenesis inhibitors for the treatment of hematologic malignancies is particularly attractive because it may target not only the environment but also the malignant cells.

Serum levels of angiogenin, basic fibroblast growth factor and endostatin in patients receiving intensive chemotherapy for acute myelogenous leukemia

Angiogenesis seems to be important both in the pathogenesis of acute myelogenous leukemia (AML) and for the susceptibility of AML blasts to chemotherapy. Recent clinical studies even suggest that antiangiogenic therapy can induce disease control in patients with AML relapse. In this context we have investigated the profile of the systemic component of angiogenic regulation in AML by characterizing the serum levels of (i) the angiogenic regulators angiogenin, basic fibroblast growth factor (bFGF) and endostatin; (ii) the endothelial cell marker soluble (s) E-selectin. Patients with untreated AML had increased levels of angiogenin, endostatin and sE-selectin, whereas the levels of bFGF were not significantly altered. The systemic levels of the proangiogenic bFGF, the antiangiogenic endostatin and the endothelial cell marker sE-selectin showed significant correlations, whereas angiogenin and sE-selectin levels were not correlated. Furthermore, intensive chemotherapy resulted in decreased systemic levels of the 2 proangiogenic mediators angiogenin and bFGF, whereas endostatin levels remained high after treatment. Although angiogenin normally is a part of the acute phase reaction, its systemic levels were not altered when patients with chemotherapy-induced cytopenia developed complicating bacterial infections. Our results suggest that intensive chemotherapy can modulate the systemic component of angiogenic regulation in AML patients.