Effects of the cyclooxygenase inhibitor, piroxicam, in combination with chemotherapy on tumor response, apoptosis, and angiogenesis in a canine model of human invasive urinary bladder cancer

The objectives of this study were: (a) to determine the antitumor activity and toxicity of a cyclooxygenase inhibitor (piroxicam) combined with cisplatin chemotherapy in dogs with naturally-occurring, invasive transitional cell carcinoma (TCC) of the urinary bladder; and (b) to determine the effects of this treatment on prostaglandin E(2) concentration, tumor cell proliferation and apoptosis, and angiogenesis. Pet dogs with naturally-occurring invasive TCC underwent complete tumor staging before and after 10 weeks of piroxicam/cisplatin treatment. Prostaglandin E(2) concentrations were determined by immunoassay in snap-frozen tumor tissues. Apoptosis (terminal deoxynucleotidyl transferase-mediated nick end labeling assay), proliferation (proliferating cell nuclear antigen), and microvessel density were determined in formalin-fixed tissues. Urine basic fibroblast growth factor and vascular endothelial cell growth factor concentrations were determined by immunoassay. Partial remission (> or =50% reduction in tumor volume) was noted in 6 of 12 dogs treated with piroxicam/cisplatin. Renal toxicity was dose-limiting. Apoptotic index doubled with treatment in 11 of 12 dogs but was not associated with tumor response. Proliferative index decreased in five dogs, and tumor decreased in size in three of the five dogs. Change in urine basic fibroblast growth factor and vascular endothelial cell growth factor was associated with tumor response. microvessel density was not associated with tumor response. In conclusion, piroxicam/cisplatin had antitumor activity against canine TCC, a disease that closely mimics human invasive urinary bladder cancer. Strategies to prevent renal toxicity of this protocol are needed. Induction of tumor apoptosis and reduction in angiogenic factor concentrations were observed, but additional studies are needed to further define the mechanisms of the antitumor activity of piroxicam/cisplatin.

Clinical pharmacokinetics, pharmacodynamics and metabolism of the novel matrix metalloproteinase inhibitor ABT-518

PURPOSE

To investigate the pharmacokinetics, pharmacodynamics and metabolism of the novel matrix metalloproteinase (MMP) inhibitor ABT-518.

METHODS

Plasma and urine samples were obtained from six patients included in a phase I trial in which ABT-518 was given once daily via the oral route. Samples were analyzed by LC-MS/MS, ELISA and immunocapture assay. The pharmacokinetics of the parent compound and of detectable metabolites were calculated.

RESULTS

After a single dose of ABT-518 peak plasma levels were reached within 4-8 h. ABT-518 had an estimated clearance (Cl/F) of approximately 3 l/h, an estimated volume of distribution (V/F) of over 70 l and a terminal half-life (T(1/2)) of 20 h. At least six different metabolites were formed. Pharmacodynamic analysis for angiogenic growth factors (bFGF and VEGF) showed plasma and urine levels in the picogram range and for total MMP-9 and MMP-2 or MMP-9 activity showed plasma and urine levels in the nanogram range.

CONCLUSIONS

The MMP inhibitor ABT-518 is extensively metabolized in humans. No significant correlations between pharmacokinetics and pharmacodynamics could be established.

Phase I clinical trial of recombinant human endostatin administered as a short intravenous infusion repeated daily

PURPOSE

To perform a phase I trial of recombinant human endostatin (rhEndostatin; EntreMed, Rockville, MD) given as a daily 20-minute intravenous (IV) injection in adult patients with refractory solid tumors.

PATIENTS AND METHODS

The daily dose was increased from 15 to 240 mg/m(2) by a factor of 100% in cohorts of three patients. In the absence of dose-limiting toxicity, uninterrupted treatment was continued until the tumor burden increased by more than 50% from baseline. Correlative studies included dynamic contrast-enhanced magnetic resonance imaging of tumor blood flow, urinary vascular endothelial growth factor and basic fibroblast growth factor levels, rhEndostatin serum pharmacokinetics, and monitoring of circulating antibodies to rhEndostatin.

RESULTS

There were no notable treatment related toxicities among 15 patients receiving a total of 50 monthly cycles of rhEndostatin. One patient with a pancreatic neuroendocrine tumor had a minor response and two patients showed disease stabilization. Linearity in the pharmacokinetics of rhEndostatin was indicated by dose-proportionate increases in the area under the curve for the first dose and the peak serum concentration at steady state. Daily systemic exposure to rhEndostatin in patients receiving 240 mg/m(2)/d was approximately 50% lower than that provided by the therapeutically optimal dose in preclinical studies.

CONCLUSION

rhEndostatin administered as a 20-minute daily IV injection at doses up to 240 mg/m(2) showed no significant toxicities. Evidence of clinical benefit was observed in three patients. Due to high variability between the peak and trough serum concentrations associated with the repeated short IV infusion schedule, daily serum drug levels only briefly exceeded concentrations necessary for in vitro antiangiogenic effects.

Results of a Phase I dose-escalating study of the antiangiogenic agent, SU5416, in patients with advanced malignancies

SU5416 is a small molecule antiangiogenic agent that inhibits vascular endothelial growth factor (VEGF) stimulation of the KDR tyrosine kinase receptor. In this Phase I dose escalation trial, a weekly dose schedule of SU5416 was tested whereby an initial 5-day loading dose was followed by weekly maintenance infusions. The start dose was 20 mg/m(2) for the loading dose followed by 65 mg/m(2) for the weekly infusions. Dose escalations occurred at 33% until a final dose of 65 mg/m(2) (loading dose) and 190 mg/m(2) (weekly infusion) was obtained. Twenty-two patients were treated at five dose levels; tumor types included gastrointestinal (8), breast (3), lung (4), sarcoma (2), and other (5). The most common serious drug-related toxicity was headache, often associated with nausea and vomiting. Grade 1 and 2 toxicities included headache, nausea, vomiting, asthenia, pain at the infusion site, phlebitis, change in voice, and fevers. Of 19 evaluable patients, 4 obtained clinical benefit as defined by tumor regression (1) or disease stabilization for at least 12 weeks (3). Pharmacokinetic data revealed that the weekly infusion schedule prevented the reported 50-60% induction in SU5416 clearance observed with either daily or twice weekly dosing. Higher baseline levels of urine VEGF were observed in the 4 patients who gained clinical benefit, suggesting this may be a useful marker for predicting response to anti-VEGF therapies. Our results suggest that a weekly schedule of SU5416 shows signs of biological activity and is well tolerated at doses up to 145 mg/m(2).

Mediation of systemic vascular hyperpermeability in severe psoriasis by circulating vascular endothelial growth factor

BACKGROUND

Severe forms of psoriasis can be complicated by systemic microvascular hyperpermeability. Vascular endothelial growth factor (VEGF) possesses potent vascular permeability activity. We suggest that VEGF enters the systemic circulation and acts on microvessels to mediate hyperpermeability.

OBJECTIVES

To quantify renal microvascular permeability and circulating VEGF concentration in severe psoriasis, and to investigate the relationship between plasma VEGF concentration and skin and joint involvement.

DESIGN

Inception cohort studies of patients with generalized pustular psoriasis and plaque psoriasis.

SETTING

St John's Institute of Dermatology, London, England.

PATIENTS

Twenty-two patients (15 men and 7 women) with moderate and severe psoriasis were recruited (age range, 29-77 years; mean age, 47 years); 5 had generalized pustular psoriasis, 2 had erythrodermic psoriasis, and 15 had moderate-severe plaque psoriasis. An age- and sex-matched control group of 17 individuals (10 men and 7 women) was recruited (age range, 29-69 years; mean age, 42 years).

RESULTS

There was pathological proteinuria in patients with relapsing generalized pustular psoriasis, (4-fold increase in urinary protein excretion rate in relapse compared with remission). In patients with moderate and severe psoriasis, mean plasma VEGF concentration during relapse was approximately 2.5 times greater than during remission (mean VEGF(relapse) = 257 pg/mL; mean VEGF(remission) = 103 pg/mL; P<.01). There was a correlation between extent of skin involvement and plasma VEGF level (mean VEGF(severe psoriasis) = 365 pg/mL; mean VEGF(moderate psoriasis) = 149 pg/mL; P =.03). There was a correlation between presence of psoriatic arthritis and plasma VEGF level (mean relapse VEGF(arthritis) = 277 pg/mL; mean relapse VEGF(nonarthritis) = 103.5 pg/mL; P =.03).

CONCLUSIONS

Generalized pustular psoriasis is accompanied by pathological proteinuria and elevated plasma VEGF levels. Plasma VEGF concentration is significantly elevated in patients with extensive skin and joint involvement and may act on renal microvasculature to induce hyperpermeability.

Clinical significance of vascular endothelial growth factor and hepatocyte growth factor in multiple myeloma

Angiogenesis is a crucial process in the progression of multiple myeloma (MM). Vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) are multifunctional cytokines that potently stimulate angiogenesis including tumour neovascularization. Serum levels of VEGF and HGF were measured in 52 patients with MM by enzyme-linked immunosorbent assay (ELISA). Serum levels of VEGF and HGF were elevated in MM patients compared with healthy controls (VEGF: mean 0.31 ng/ml and 0.08 ng/ml respectively, P < 0.01; HGF: mean 2.17 ng/ml and 0.45 ng/ml, respectively, P < 0.001). In serial samples taken after chemotherapy, serum VEGF and HGF levels were correlated with M-protein levels. Serum levels of VEGF were higher in patients with extramedullary plasmacytomas than in patients without them (P < 0.05). They were also significantly higher in a group of patients who showed poor response to chemotherapy (P < 0.01). Serum levels of HGF were higher in patients with complications such as anaemia, hypercalcaemia and amyloidosis than in patients without these complications (P < 0.01, P < 0.05, P < 0.05 respectively). Both serum VEGF and HGF levels were significant predictors of mortality (P = 0.01, P = 0.02, respectively, log-rank test). The present study demonstrated that serum levels of VEGF and HGF are significantly elevated and dependent on the severity of MM, suggesting that measurement of VEGF and HGF may be useful for assessing disease progression and for predicting the response to chemotherapy in MM patients.

Effects of the cyclooxygenase inhibitor, piroxicam, on tumor response, apoptosis, and angiogenesis in a canine model of human invasive urinary bladder cancer

The mechanisms by which cyclooxygenase inhibitors exert antitumor effects are not completely defined but are postulated to involve antiangiogenic effects and induction of apoptosis. In this study, we determined the effects of the cox inhibitor, piroxicam, on tumor response, apoptotic index, proliferative index, cyclooxygenase-2 expression, prostaglandin E(2) concentration, tumor microvessel density, and urine basic fibroblast growth factor and vascular endothelial growth factor concentrations in pet dogs with naturally occurring invasive transitional cell carcinoma of the urinary bladder. Piroxicam caused reduction in tumor volume in 12 of 18 dogs, and this was strongly associated with induction of apoptosis (Fisher's exact test P < 0.015) and reduction in urine basic fibroblast growth factor concentration.

Clinical significance of urinary vascular endothelial growth factor and microvessel density in patients with renal cell carcinoma

OBJECTIVES

To investigate the urinary vascular endothelial growth factor (VEGF) levels from patients with renal cell carcinoma (RCC). Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors. VEGF is thought to exert potent angiogenic activity.

METHODS

Urine samples were obtained before radical nephrectomy from 27 patients with RCC and 10 control subjects with no evidence of cancer or inflammatory disease. VEGF was measured by enzyme-linked immunosorbent assay in the urine and corrected according to the 24-hour urine concentration of creatinine. The microvessel density was measured by immunohistochemical staining with CD31 monoclonal antibody. Nuclear morphometry was performed by photomicroscopy.

RESULTS

The corrected urinary VEGF levels in patients with RCC were much higher than those in the normal control group (P = 0.039) and were more elevated in patients with higher stages of RCC (Stages III and IV versus Stages I and II; P = 0.024). A tendency was also noted for the VEGF levels to be higher according to cell grade. However, no statistical correlation was found between the corrected urinary VEGF and age, sex, tumor size, cell type, microvessel density, platelet count, or hemoglobin. The nuclear area was higher with more advanced-stage tumors (P = 0.043) and tended to increase according to the tumor cell grade.

CONCLUSIONS

The results of this study indicate that urinary VEGF levels are increased in patients with RCC. However, they may not reflect the underlying angiogenic activity, and it may be that other angiogenic factors play a more prominent role.

Clinical significance of urinary vascular endothelial growth factor in patients with superficial bladder tumors

Vascular endothelial growth factor (VEGF) is an important mediator of tumor angiogenesis and has been shown to be excreted in the urine of bladder cancer patient. The goal of this study was to evaluate urinary VEGF levels of patients with superficial bladder transitional cell carcinoma (TCC) and to determine its predictive value for recurrence. Pre-operative urinary VEGF levels were determined in 31 patients with superficial bladder TCC and 10 control patients. A quantitative enzyme immunoassay was used to measure urinary VEGF levels and the urine VEGF concentration was corrected by the creatinine concentration in a 24-h urine specimen. The corrected urinary VEGF levels were higher in patients than controls (p=0.003). Ten of 31 patients had TCC recurrences during this study. Corrected urinary VEGF levels were significantly higher in recurrent vs. non-recurrent patients (p=0.001). A cut-off value of 0.32 (corrected urinary VEGF levels) was valuable for predicting recurrences in this prospective study. However, there was no statistical correlation between VEGF levels and tumor stage (Ta or T1), tumor size or tumor grade. Pre-operative urinary VEGF levels are associated with a risk of recurrence in patient with superficial bladder TCC. Quantification of urinary VEGF may prove to be a valuable, non-invasive indicator of carcinoma recurrence in patients with superficial bladder TCC. Urinary VEGF may be a therapeutic target for intravesical therapy. However, because of the small number of cases, further studies with larger number of patients will be needed to clarify this issue.

Quantification of angiogenesis stimulators in children with solid malignancies

Humoral angiogenesis stimulators including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) have been implicated in the pathogenesis of solid malignancies. However, it has remained unclear whether both stimulators contribute to the development and progression of solid malignancies of children. The aim of the present study was to determine whether VEGF and bFGF are elevated in body fluids of children with solid malignancies and, if so, whether these elevated levels correlate with clinical parameters. Using enzyme-linked immunosorbent assays (ELISAs), we quantified VEGF and bFGF in serum (n = 107) and urine (n = 57) of healthy children and of children with solid malignancies (serum: n(VEGF) = 69, n(bFGF) = 60; urine: n(VEGF) or n(bFGF) = 13). Finally, we compared patients' pre-therapeutic and post-therapeutic levels. Serum VEGF was elevated in children with several solid tumors (Ewing's sarcoma, primitive neuroectodermal tumours, malignant lymphoma, Langerhans cell histiocytosis and medulloblastoma). In contrast, serum bFGF, urinary bFGF or urinary VEGF were not significantly elevated. Upon successful therapy, elevated pre-therapeutic serum VEGF levels declined to levels present in healthy children. VEGF could contribute to the progression of pediatric solid malignancies, and serum VEGF could be used to monitor therapeutic response. Furthermore, the determination of angiogenesis stimulators could identify patients eligible for anti-angiogenic therapy.

Elevated vascular endothelial growth factor levels in the urine of patients with minimal-change nephrotic syndrome

BACKGROUND

Vascular endothelial growth factor (VEGF) is a selective endothelial mitogen and vascular permeability factor (VPF), that is mainly produced by activated monocytes/macrophages and T cells. To our knowledge, very little is known about the involvement of VEGF in minimal-change nephrotic syndrome (MCNS). The aim here was to define further the involvement of VEGF in MCNS.

PATIENTS AND METHODS

Urine samples were obtained from 20 MCNS patients. The disease controls included 20 patients with IgA nephropathy (IgAN). The samples were assayed for VEGF protein by a sandwich enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared with normal controls, markedly increased urinary levels of VEGF were detected in both MCNS and IgAN patients with the nephrotic syndrome (NS). The urinary VEGF (uVEGF) levels correlated with the degree ofproteinuria in MCNS and IgAN patients. Moreover, when individual MCNS patients were followed through their clinical illness, uVEGF levels were increased during the active phase and decreased as the patients went into remission. Our main concern is to distinguish between two possibilities: Increases in uVEGF excretion might indeed relate to specific glomerular pathology and thus have a pathophysiological role. Alternatively, uVEGF may be derived from the circulation and as such may be nothing more than an assay for proteinuria. In fact, given the strict correlation between uVEGF excretion and the amount of proteinuria, the second possibility appears quite conceivable.

CONCLUSION

Therefore, this may be a coincidental finding which has no bearing on the pathophysiology of MCNS.

Vascular endothelial growth factor and basic fibroblast growth factor urine levels as predictors of outcome in hormone-refractory prostate cancer patients: a cancer and leukemia group B study

Better prognostic markers are needed for hormone-refractory prostate cancer (HRPC) patients. No single biochemical or clinical parameter can reliably predict patient response to therapy or rapidity of disease progression. Peptide factors involved in major cancer growth pathways, such as tumor angiogenesis, are attractive candidates as markers of low- and high-risk HRPC patients. We analyzed prospectively collected urine specimens from 100 of 390 HRPC patients undergoing therapy with the growth factor antagonist suramin as part of CALGB 9480. Levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were assessed from day 1 of therapy (D1) and day 29 (D29) urine samples from this subset of 100 randomly selected patients. Growth factor levels were determined by standardized ELISA microtiter plate assays from a commercial (bFGF) or proprietary (VEGF) source. Pretreatment urine VEGF levels were predictive of survival. In univariate analysis, patients whose baseline urine VEGF level was < or =28 pg/ml (the median level) had an average survival of 17 months; those with baseline VEGF >28 pg/ml had a significantly shorter survival of 10 months (P = 0.024). This difference corresponded to a 60% increased risk of dying for the higher urine VEGF patients (hazard ratio, 1.62; P = 0.03) and remained significant in multivariate analysis (hazard ratio, 1.72, P = 0.02). No significant correlations between urine bFGF level or change in bFGF levels and survival were found. These results support the notion that certain peptide growth factor-mediated, mitogenic pathways are important in HRPC and that their levels can predict outcome.

Are basic fibroblast growth factor and vascular endothelial growth factor prognostic indicators in pediatric patients with malignant solid tumors?

Angiogenesis plays an important role in the growth, progression, and metastasis of solid tumors. Among angiogenic factors, basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) appear to be useful markers in adults with cancer. The aim of this pilot study was to determine the levels of VEGF in serum and bFGF in serum and urine of children with solid tumor at diagnosis (as measured by ELISA), and to investigate whether these parameters provide prognostic information. Forty consecutive patients with different types of cancer were prospectively included in this study. Median values of all studied angiogenic factors were higher in patients than in controls (n = 40), and the differences were statistically significant for bFGF in serum and urine: 10 versus 3 pg/ml (P = 0.0004) and 6406 versus 0 pg/g of creatinine (P < 0.0001), respectively. Among patients, median serum values of bFGF and VEGF were higher in children with metastatic disease (n = 14) than in those with localized disease (n = 26). The difference was statistically significant for serum bFGF: 17.5 versus 6 pg/ml (P = 0.02). Serum angiogenic factor levels correlated with outcome. The estimated event-free survival at 3 years was 79% for patients with normal bFGF values (n = 13) versus 42% (n = 26; P = 0.02) for those with high levels, and 71% in case of normal VEGF values (n = 20) versus 38% (n = 19; P = 0.04) for those with high levels. No benefit of normal urinary bFGF values was observed. Our results provide a rationale for exploring the clinical interest of bFGF and VEGF measurements in body fluids of a larger group of children with cancer.

Do urinary levels of vascular endothelial growth factor predict proliferative retinopathy?

PURPOSE

Vascular endothelial growth factor (VEGF) is elevated in the vitreous of patients with proliferative retinopathies (PR). Angiogenic factors like VEGF are elevated in the urine of subjects with cancers, including those distant from the genitourinary tract. We hypothesized that local increases in VEGF in the vitreous would be reflected in the urine of subjects with PR.

METHODS

Urine samples were collected from adults with absent, mild, or severe (requiring laser photocoagulation) PR. VEGF was measured by enzyme linked immunosorbent assay.

RESULTS

Of 42 subjects, 16 had no PR and 26 had PR (8 mild, 18 severe). Thirty subjects had diabetes mellitus; 24 of these had PR. Subjects with PR were older than controls. Subjects with PR tended to have higher urinary VEGF (median 123 pg/ml Cr, range 3--1738) than controls without PR (median 93 pg/ml Cr, range 2--200) (p = 0.08). None of 16 controls, but 11/15 subjects with PR had >200 mg VEGF/mg Cr (p = 0.003), yielding high specificity (100%), but poor sensitivity (42%) of elevated urinary VEGF for PR. Urinary VEGF was also modestly correlated with urinary protein excretion (r(2 ) = 0.23). Correction of VEGF values for urinary protein abrogated any correlation with PR.

CONCLUSIONS

Urinary levels of VEGF are associated with PR, but this relationship may be caused by concurrent renal diseases that result in proteinuria and/or renal VEGF production. The insensitivity of the association may preclude its use in screening to avoid eye examinations.

A phase II study of razoxane, an antiangiogenic topoisomerase II inhibitor, in renal cell cancer with assessment of potential surrogate markers of angiogenesis

Renal cell carcinoma (RCC) is an angiogenic tumor resistant to standard cytotoxic chemotherapeutic agents. Although often responsive to immunomodulatory agents including interleukin 2 and IFN-alpha, the overall results in randomized Phase III studies are disappointing with only modest improvements in overall survival. This Phase II study evaluated the efficacy and tolerability of razoxane, an antiangiogenic topoisomerase II inhibitor, in 40 patients (32 men, 8 women; age: range, 31-76 years; median, 58 years) with inoperable RCC. Twenty patients received razoxane 125 mg p.o., twice a day for 5 days each week for 8 weeks (one cycle). This was repeated in patients with stable disease (StD), but was discontinued after 16 weeks if there was no evidence of an objective response. Because minimal toxicity was seen, subsequent patients (n = 20) were treated until progressive disease (PD) was documented. Of 38 evaluable patients, 11 (29%) had StD for a minimum of 4 months, and the remainder had PD. Median overall survival was 7.3 months. Duration of survival was significantly better in patients with StD compared with those with PD (P = 0.003). The effect of treatment on six potential surrogate serum/plasma (vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), urokinase plasminogen activator soluble receptor (uPAsr), E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and von Willebrand's factor (vWF) and two urinary (VEGF and bFGF) markers of angiogenesis was evaluated before and after 1 cycle of treatment. Pretreatment serum VEGF and E-selectin levels above the median value were associated with a poor prognosis. Serum VCAM-1 levels and urinary VEGF levels rose significantly after one cycle in patients with PD but not in those with StD. Serum VEGF, bFGF, VCAM-1 and vWF, plasma uPAsr and urinary bFGF levels were significantly higher in PD patients compared with StD patients before and/or after 1 cycle of treatment. In conclusion, razoxane is an antiangiogenic agent that has minimal toxicity and that requires further evaluation in combination with other active agents in the treatment of RCC. Surrogate serum and urinary markers of angiogenesis may have a role to play in predicting disease response and overall survival in RCC.

Increased bone marrow angiogenesis in B cell chronic lymphocytic leukemia

Recent studies have shown that angiogenesis may be involved in the pathogenesis of hematopoietic malignancies, apart from its well-characterized role in the growth and metastasis of solid tumors. In this study, we quantified the degree of angiogenesis in B cell chronic lymphocytic leukemia (B-CLL) by measuring the microvessel density and hotspot density in bone marrow trephine biopsy sections with B-CLL involvement (n = 12) and compared it to normal bone marrow sections (n = 11). The B-CLL samples had a mean microvessel count/high power field (hpf) of 7.64 while the control samples had a mean microvessel count/hpf of 2.11 (P = 0.0001). The mean hotspot density in the B-CLL sections (14.83/hotspot) was also significantly higher (P = 0.0008) than the mean hotspot density in control bone marrow sections (7.09/hotspot). Both the microvessel density and hotspot density correlated positively with the clinical stage of the B-CLL patients. In a separate cohort of B-CLL patients, the median urine level of the angiogenic peptide, basic fibroblast growth factor (2216.5 pg/g, n = 14), was significantly higher (P = 0.0001) than the bFGF level in normal controls (1,084 pg/g, n = 58). These results indicate that angiogenesis may be involved in the pathogenesis of B-CLL.

Decreased urinary excretion of vascular endothelial growth factor in idiopathic membranous glomerulonephritis

BACKGROUND

Membranous glomerulonephritis (MGN) has, for unknown reasons, an unpredictable and highly variable clinical course. Vascular endothelial growth factor (VEGF) enhances endothelial cell proliferation, angiogenesis, microvascular permeability, and monocyte chemotaxis, and it activates proteinases. In normal kidneys, it is predominantly expressed by glomerular podocytes, where its physiological function and role in development of renal diseases are obscure. This study was designed to evaluate the urinary excretion of VEGF in MGN compared with several other glomerular disease and to asses its relationships to the clinical activity of MGN.

METHODS

Urinary VEGF was studied during renal biopsy using a sandwich enzyme immunoassay from 30 patients with idiopathic MGN, 8 with minimal change glomerulonephritis, 10 with focal segmental glomerulosclerosis (FSGS), 8 with necrotizing glomerulonephritis associated with systemic vasculitis, and 12 with diabetic nephropathy. In addition, 33 healthy controls were examined. Fifteen patients with MGN were re-evaluated 12 months later, and the evolution of proteinuria was compared with changes in urinary VEGF excretion.

RESULTS

In healthy control subjects, urinary VEGF excretion was 68 +/- 10 (95% CI, 49 to 88) ng/mmol creatinine (UCr). In MGN, the excretion was decreased to 16 +/- 3 (CI, 10 to 23) ng/mmol crea (P < 0.0001, ANOVA), whereas in minimal change glomerulonephritis and diabetic nephropathy, it was unchanged [55 +/- 14 (CI, 24 to 86) and 101 +/- 25 (CI, 45 to 156) ng/mmol UCr, respectively, P = NS]. In vasculitis and FSGS patients, the excretion was higher than normal [184 +/- 68 (CI, 24 to 344), P = 0.01, and 160 +/- 29 (CI 95 to 226), P = 0.002 ng/mmol UCr, respectively]. The excretion did not correlate with serum VEGF, renal function, or proteinuria. In the follow-up of 15 patients, improving MGN (decreasing proteinuria) was associated with increasing VEGF excretion, while persistent disease (no change or increase of proteinuria) was associated with constantly low urinary VEGF excretion. The change in urinary protein excretion over one year correlated inversely with the change in urinary VEGF (r = -0.57, P = 0.026).

CONCLUSIONS

MGN is associated with decreased urinary VEGF compared with normal subjects, which is in contrast with other proteinuric diseases. Moreover, decreasing clinical activity (proteinuria) is accompanied by increasing VEGF excretion. Urinary VEGF may serve as an indicator of activity of MGN.

[VEGF is an essential molecule for glomerular endothelial cells and its excretion in urine might be a unique marker of glomerular injury]

A glomerulus is a functional unit of the kidney, and endothelial cells in the glomerulus are often exposed to more than 5 times higher pressure than peripheral capillaries. Glomerular development proceeds through angiogenesis and VEGF was shown to mediate the angiogenesis. VEGF is constitutively expressed in the glomerulus from the embryo to adults. When VEGF signal was blocked by the antibody, glomerular endothelial cells were swollen and capillary lumen was interrupted. Changes were more prominent in the juxta-medullary than in the cortical glomerulus. A major VEGF receptor, Flk-1/KDR, is specifically localized to the glomerular endothelial cell among tissues and more predominantly in the juxta-medullary than in the cortical glomerulus. As capillary pressure is higher in the juxta-medullary than in the cortical glomeruli, endothelial cells in the former are exposed to more tension than those in the latter. VEGF might be a protective molecule for endothelial cells against tension. The effect of VEGF on the repair of an impaired glomerulus was evaluated in the rat Thy-1 glomerulonephritis. VEGF inhibited early endothelial injury and accelerated consequent remodeling of the glomerulus. In the patient study, VEGF excretion in the urine was independent from its serum or plasma level, but increased as renal function decreased. VEGF signaling is essential in glomerular development, maintenance and repair. VEGF excreted in the urine might reflect its generation in the kidney and be a unique marker of renal function.

Continuous low dose Thalidomide: a phase II study in advanced melanoma, renal cell, ovarian and breast cancer

To grow and metastasize, solid tumours must develop their own blood supply by neo-angiogenesis. Thalidomide inhibits the processing of mRNA encoding peptide molecules including tumour necrosis factor-alpha (TNF-alpha) and the angiogenic factor vascular endothelial growth factor (VEGF). This study investigated the use of continuous low dose Thalidomide in patients with a variety of advanced malignancies. Sixty-six patients (37 women and 29 men; median age, 48 years; range 33-62 years) with advanced measurable cancer (19 ovarian, 18 renal, 17 melanoma, 12 breast cancer) received Thalidomide 100 mg orally every night until disease progression or unacceptable toxicity was encountered. Three of 18 patients with renal cancer showed partial responses and a further three patients experienced stabilization of their disease for up to 6 months. Although no objective responses were seen in the other tumour types, there were significant improvements in patients' sleeping (P < 0.05) and maintained appetite (P < 0.05). Serum and urine concentrations of basic fibroblast growth factor (bFGF), TNF-alpha and VEGF were measured during treatment and higher levels were associated with progressive disease. Thalidomide was well tolerated: Two patients developed WHO Grade 2 peripheral neuropathy and eight patients developed WHO grade 2 lethargy. No patients developed WHO grade 3 or 4 toxicity. Further studies evaluating the use of Thalidomide at higher doses as a single agent for advanced renal cancer and in combination with biochemotherapy regimens are warranted.

Urinary vascular endothelial growth factor and its correlation with bladder cancer recurrence rates

PURPOSE

Vascular endothelial growth factor (VEGF) is a principal growth factor mediating tumor angiogenesis. The high expression of VEGF within bladder tumors is associated with a poor prognosis. We quantified urinary VEGF and determined its potential as a prognostic marker in bladder cancer.

MATERIALS AND METHODS

VEGF was measured by enzyme-linked immunosorbent assay in the urine of 261 patients, including 153 undergoing cystoscopic surveillance for bladder cancer and 108 with another advanced malignancy or a benign urological condition. The source of urinary VEGF was studied through its quantification in bladder tumors and normal bladders.

RESULTS

Urinary VEGF was higher in patients undergoing cystoscopic surveillance for bladder cancer than in those with an advanced nonbladder malignancy (p <0.0001) or a benign urological condition (p = 0.004). The highest levels were noted in patients with bladder cancer compared to those with clear cystoscopy (p <0.0001). In 26 cases the correlation between VEGF protein levels in bladder cancer and urine (r = 0.67, p = 0.003) suggested that the tumor is a source of urinary VEGF. Increased VEGF protein in normal urothelium in 22 patients with bladder cancer compared to that in 7 cadaveric organ donors (p = 0.002) indicates that urinary VEGF may also be derived from nonmalignant urothelium. In 61 cases we established a correlation between urinary VEGF and stage T1 or less superficial bladder tumor recurrence rates (r = 0.45, p <0.0001).

CONCLUSIONS

Our study demonstrates that VEGF is high in the urine of patients with bladder cancer and it correlates with tumor recurrence rates. VEGF is implicated in the pathogenesis of bladder cancer recurrence. Its quantification may provide a valuable noninvasive marker for the early detection of bladder tumor recurrence as well as a therapy target.

Circulating vascular endothelial growth factor is not increased during relapses of steroid-sensitive nephrotic syndrome

BACKGROUND

An uncharacterized circulating factor that increases vascular permeability has previously been described in childhood steroid-sensitive nephrotic syndrome (SSNS). The aim of this study was to determine whether this factor is vascular endothelial growth factor (VEGF), the recently described endothelial cell mitogen and enhancer of vascular permeability.

METHODS

Plasma and urine VEGF levels were measured in children with SSNS in both relapse and remission and in normal age- and sex-matched controls. Semiquantitative reverse transcriptase-polymerase chain reaction studies investigating VEGF mRNA expression were performed on peripheral blood mononuclear cells isolated from children with SSNS in relapse and controls. In two experimental models (one-hour and three-day follow-up postinfusion), Sprague-Dawley rats were intravenously administered 50 microg rVEGF to determine whether this induced either proteinuria or glomerular histologic change.

RESULTS

Plasma VEGF levels and urine VEGF/creatinine ratios were not elevated in SSNS relapse compared with remission and control samples. Peripheral blood mononuclear cell VEGF mRNA expression was no different in SSNS patients compared with controls. The administration of VEGF to rats induced an acute reversible fall in systemic blood pressure but did not result in the development of either proteinuria or glomerular histologic change.

CONCLUSION

Increased circulating VEGF levels are not responsible for the proteinuria observed during relapses of SSNS. Further studies are warranted to investigate intrarenal VEGF expression.

Endothelial cell proliferation activity in benign prostatic hyperplasia and prostate cancer: an in vitro model for assessment

PURPOSE

Urinary excretion of several pro-angiogenic and antiangiogenic substances has been correlated with malignant tumor growth. The aim of this study was to assay angiogenic activity in urine from patients with cancer of the prostate and benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

Urine specimens from 22 healthy male volunteers (control), 33 patients with BPH and 29 with organ confined prostate cancer were analyzed for angiogenic activity in a bovine capillary endothelial cell proliferation assay. In parallel the concentration of basic fibroblast growth factor and vascular endothelial growth factor was determined by enzyme immunoassay in the corresponding urine specimens.

RESULTS

Urine samples from patients with BPH and prostate cancer increased bovine capillary endothelial cell proliferation by 13.1% and 15.1%, respectively, whereas urine from the control group showed a significantly lower angiogenic activity, increasing endothelial cell proliferation by only 0.7% (p = 0.001). Urinary basic fibroblast growth factor and vascular endothelial growth factor were highest in patients with BPH and lowest in the group with prostate cancer (p = 0.0001).

CONCLUSIONS

Urine from patients with BPH and prostate cancer stimulates endothelial cell proliferative activity. The degree of endothelial cell stimulation does not correlate with the concentration of basic fibroblast growth factor or vascular endothelial growth factor. Whether the observed pro-angiogenic activity is due to an increased production or release of (an) other angiogenic factor(s) and/or loss of (an) angiogenesis inhibitor(s), deserves further investigation.

Elevated ocular levels of vascular endothelial growth factor in patients with von Hippel-Lindau disease

BACKGROUND

Von Hippel Lindau disease (VHL) is a rare autosomal dominant inherited disorder characterized by highly vascularized tumors in various organs. The abundant presence of endothelial cells in VHL tumors strongly suggest a role of the VHL tumor suppressor gene in the regulation of angiogenesis. Recently, in vitro studies have shown that the VHL tumor suppressor gene regulates the expression of vascular endothelial growth factor (VEGF). We investigated whether VHL patiens have increased levels of VEGF in their body fluids.

PATIENTS AND METHODS

The concentration of VEGF was measured in fluid of the anterior chamber of the eye, serum, urine, and fluid from renal cysts of VHL patients and unaffected individuals by ELISA. In addition, levels of basic fibroblast growth factor (bFGF), interleukin-8 (IL-8) and endothelin-1 (ET-1) were measured in urine and serum of VHL patients and control subjects.

RESULTS

In 80% of the VHL patients VEGF was detectable in aqueous fluid of the anterior chamber of their eyes. A strong positive correlation (r = 0.90) was found between the age of VHL patients and ocular VEGF concentrations. At comparable age, VEGF levels in ocular fluid of VHL patients were significantly higher (P < 0.001) than in unaffected subjects. No correlation was found between VEGF concentration and the presence of retinal angiomas. A 10 and 16 fold increase of VEGF concentration was seen in fluid from two independent VHL-related cysts as compared with VEGF serum levels of the same patient. The mean concentration of VEGF in serum of VHL patients (n = 15) (319 +/- 84 pg/ml) was higher than in matched controls (238 +/- 68 pg/ml; P = NS). The mean concentration of VEGF in urine of VHL patients (128 +/- 36 pg/ml) was lower than in matched controls (183 +/- 25 pg/ml; P = NS). Concentrations of VEGF did not correlate with the presence of VHL-related tumors. No differences were observed between concentrations of bFGF, IL-8 and ET-1 in serum and urine of VHL patients and matched controls.

CONCLUSIONS

These findings support a role for the VHL tumor suppressor gene in the in vivo regulation of VEGF.

Angiogenic factors as tumor markers

The process of angiogenesis plays a critical role in tumor growth and metastasis. Recently, there has been much interest in the possible use of angiogenic growth factors as tumor markers. This paper will review the results thus far of attempts at measuring various angiogenic factors in bodily fluids. In the future, angiogenic factors will most likely be useful as a monitor of therapy and/or a predictor of outcome after cancer has been diagnosed.

Mechanisms of proteinuria: vascular permeability factor in congenital nephrotic syndrome of the Finnish type

Vascular permeability factor (VPF) is the most potent known mediator of vessel wall permeability. In the kidney, it is expressed preferentially in the glomerular visceral epithelial cells. The present study was designed to clarify the proposed role of VPF in diseases with increased glomerular permeability as here exemplified by the congenital nephrotic syndrome of the Finnish type (CNF). For this, we studied the expression levels and the sites of synthesis of VPF and its kinase-insert domain receptor (KDR) in kidneys of patients with CNF using Northern and in situ hybridization techniques and immunohistologic staining with anti-VPF antibody. In addition, we extended the study to include analysis of fetal kidney tissue and cultured glomerular cells of normal and CNF kidneys. In CNF and in normal kidneys VPF was localized in the visceral epithelial aspect of the glomeruli and in the collecting ducts, as also earlier described. A new finding was its localization also in the juxtaglomerular area. The VPF receptor KDR was found in glomeruli in the endothelial cells, but it was not detected in the peritubular capillaries. no consistent differences in the levels of VPF or KDR mRNAs or in their sites of production were seen in CNF and control samples. Also the distribution of VPF antigen in the CNF kidneys and normal kidneys was similar. Thus, we propose that VPF and KDR are not directly involved in the pathogenesis of the proteinuria in CNF.

Nuclease-resistant nucleic acid ligands to vascular permeability factor/vascular endothelial growth factor

BACKGROUND

Vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) is a potent inducer of new blood vessel growth (angiogenesis) that contributes to the pathology of many angiogenesis-associated disease states such as psoriasis, rheumatoid arthritis and cancer. Few molecular entities capable of binding to VPF/VEGF with high affinity and specificity have been described to date.

RESULTS

Nuclease-resistant 2'-amino-2'-deoxypyrimidine nucleotide RNA (2'-aminopyrimidine RNA) ligands that bind to VPF/VEGF with high affinity have been identified by iterative rounds of affinity-selection/amplification from two independent random libraries. The sequence information that confers high affinity binding to VPF/VEGF is contained in a contiguous stretch of 24 nucleotides, 5'-CCCUGAUGGUAGACGCCGGGGUG-3' (2'-aminopyrimidine nucleotides are designated with italic letters). Of the 14 ribopurines in this minimal ligand, 10 can be substituted with the corresponding 2'-O-methylpurine nucleotides without a reduction in binding affinity to VPF/VEGF. In fact, the 2'-O-methyl substitution at permissive positions leads to a approximately 17-fold improvement in the binding affinity to VPF/VEGF. The higher affinity results from the reduction in the dissociation rate constant of the 2'-O-methyl-substituted RNA ligand from the protein compared to the unsubstituted ligand. The 2'-O-methyl-substituted minimal ligand, which folds into a bulged hairpin motif, is also more thermally stable than the unsubstituted ligand. Nuclease resistance of the ligand is further improved by the 2'-O-methyl substitutions and the addition of short phosphorothioate caps to the 3'- and 5'-ends.

CONCLUSIONS

We have used the SELEX (systematic evolution of ligands by exponential enrichment) process in conjunction with post-SELEX modifications to define a highly nuclease-resistant oligonucleotide that binds to VPF/VEGF with high affinity and specificity.

Urinary vascular endothelial growth factor concentrations in women undergoing gonadotrophin treatment

A recently identified cytokine, vascular endothelial growth factor (VEGF, vascular permeability factor) has been implicated in ovarian hyperstimulation syndrome in women undergoing assisted reproduction. We postulate that circulating and urinary VEGF values increase following gonadotrophin stimulation, in parallel with the increased ovarian vascularity. A VEGF radioimmunoassay was developed using iodinated VEGF as tracer, a goat anti-VEGF serum as antiserum and recombinant human VEGF as standard. The specificity of the assay was confirmed by comparing the reverse phase high-performance liquid chromatography (HPLC) pattern of VEGF immunoactivity in urine and urine spiked with recombinant VEGF. Urine was concentrated 5-fold prior to measurement by the radioimmunoassay. VEGF:creatinine ratios in early morning urine samples were used to monitor daily urinary VEGF concentrations based on its high correlation (r = 0.77, P < 0.001) with VEGF concentrations in 24 h urine collections. No diurnal variation in VEGF:creatinine ratios was detected. VEGF:creatinine ratios were determined daily from nine women undergoing gonadotrophin-releasing hormone (GnRH) agonist/gonadotrophin treatment. In a further 16 women, early morning urine samples were collected in the peri-ovulatory period. A significant increase (P < 0.005, n = 25) was observed in VEGF:creatinine ratios following human chorionic gonadotrophin (HCG) administration. VEGF:creatinine ratios correlated poorly (r < 0.34) with plasma oestradiol, follicle number and size. It is concluded that urinary VEGF/creatinine ratios increase following HCG stimulation.

Vascular permeability factor (vascular endothelial growth factor) in guinea pig and human tumor and inflammatory effusions

Vascular permeability factor (VPF), also known as vascular endothelial growth factor, is a dimeric M(r) 34,000-42,000 glycoprotein that possesses potent vascular permeability-enhancing and endothelial cell-specific mitogenic activities. It is synthesized by many rodent and human tumor cells and also by some normal cells. Recently we developed a sensitive and specific time-resolved immunofluorometric assay for quantifying VPF in biological fluids. We here report findings with this assay in guinea pigs and patients with both malignant and nonmalignant effusions. Line 1 and line 10 tumor cells were injected into the peritoneal cavities of syngeneic strain 2 guinea pigs, and ascitic fluid, plasma, and urine were collected at various intervals. Within 2 to 4 days, we observed a time-dependent, parallel increase in VPF, ascitic fluid volume, and tumor cell numbers in animals bearing either tumor line; in contrast, VPF was not detected in plasma or urine, even in animals with extensive tumor burdens. However, low levels of VPF were detected in the inflammatory ascites induced by i.p. oil injection. In human studies, high levels of VPF (> 10 pM) were measured in 21 of 32 effusions with cytology-documented malignant cells and in only seven of 35 effusions without cytological evidence of malignancy. Thus, VPF levels in human effusions provided a diagnostic test for malignancy with a sensitivity of 66% and a specificity of 80% (perhaps as high as 97% in that six of the seven cytology-negative patients with VPF levels > 10 pM had cancer as determined by other criteria). As in the animal tumor models, VPF was not detected in serum or urine obtained from patients with or without malignant ascites. Many nonmalignant effusions contained measurable VPF but, on average, in significantly smaller amounts than were found in malignant effusions. VPF levels in such fluids correlated strongly (p = 0.59, P < 0.001) with monocyte and macrophage content. Taken together, these data relate ascitic fluid accumulation to VPF concentration in a well-defined animal tumor system and demonstrate, for the first time, the presence of VPF in human malignant effusions. It is likely that VPF expression by tumor and mononuclear cells contributes to the plasma exudation and fluid accumulation associated with malignant and certain inflammatory effusions. The VPF assay may prove useful for cancer diagnosis as a supplement to cytology, especially in tumors that grow in the pleural lining but not as a suspension in the effusions that they induce.