Antiangiogenic strategies, compounds, and early clinical results in breast cancer

Association between VEGF single nucleotide polymorphism and breast cancer in the Northern China Han population

PURPOSE

To investigate the associations of four commonly studied single nucleotide polymorphisms (SNP) of the vascular endothelial growth factor (VEGF), including -460T/C (rs833061), - 634G/C (rs2010963), - 2578C/A (rs699947), and +936T/C (rs3025039), with the incidence, aggressiveness, and tumor markers expression of breast cancer in the Northern China Han population.

METHODS

Followed the genomic DNA extraction, a total of 259 patients with breast cancer (case group) and 273 healthy women (control group) underwent genotyping by PCR-LDR SNP assays. The associations between VEGF gene polymorphisms and the incidence, aggressiveness, and tumor markers expression of breast cancer were analyzed.

RESULTS

Significant differences were observed in allele frequency and genotype distribution of - 634G/C between breast cancer cases and healthy controls (p = 0.006, 0.013). Individuals who carry the G allele more likely had a lower risk of breast cancer (OR, 0.866, 95% CI 0.782-0.959). Compared with CC genotype carriers, women who had the CG and GG genotypes demonstrated a relatively lower risk (OR, 0.860, 95% CI 0.757-0.978, p = 0.022; OR, 0.778, 95% CI, 0.656-0.924, p = 0.004, respectively). When we stratified the group of patients according to the status of tumor markers, a significant association of - 634G/C SNP and Ki-67 expression was observed. The CC genotype carriers were more likely to be characterized by high expression of Ki-67 (p = 0.031). Further analysis showed that the - 460T/-634C/-2578C/+936C haplotype was more associated with a higher risk of breast cancer (OR, 1.445, 95% CI 1.123-1.859, p = 0.004), whereas the - 460T/- 634G/- 2578C/+936C one was associated with a lower risk (OR, 0.736, 95% CI 0.563-0.963, p = 0.025).

CONCLUSIONS

In the present study, we concluded that VEGF gene - 634G/C polymorphism is related to the incidence of breast cancer in the Han population in Northern China and also might be associated with tumor proliferation index Ki-67.

[Markers of angiogenesis in tumor growth]

Angiogenesis is a process of new blood vessels formation. The role of angiogenesis in growth, invasion and metastasis of malignant tumours is nowdays universally recognized. Though, investigation of mechanisms of blood vessels formation and elaboration methods for assessment of tumour angiogenesis are still up-dated. Another important concern are different aspects of usage of immunohistochemical markers of blood vessels endothelium (CD31 and CD34) for assessment of tumour aggressiveness and prognosis. The problems of malignant lymphangiogenesis are also up-to-date. The focus is on methods of immunohistochemical visualization of forming lymphatic vessels, role of podoplanin, the most reliable marker of lymphatic vessels, in their identification, and formulization of the main criteria for lymphangiogenesis estimation, its correlation with metastatic activity and prognostic potential. Studying of angiogenesis and lymph angiogenesis in malignant tumors is important and challenging direction for researching tumour progression and invention of antiangiogenic therapy.

Association of +405C>G and +936C>T polymorphisms of the vascular endothelial growth factor gene with sporadic breast cancer in North Indians

BACKGROUND

Vascular endothelial growth factor (VEGF), an endothelial cell specific mitogen, has been implicated as a critical factor influencing tumor related angiogenesis. The aim of present study was to evaluate the relationship between VEGF +936C>T and +405C>G polymorphisms of VEGF with risk of breast cancer in Punjab, India.

MATERIALS AND METHODS

We screened DNA samples of 192 sporadic breast cancer patients and 192 unrelated healthy, gender and age matched control individuals for VEGF +936C>T and +405C>G polymorphisms using the PCR-RFLP method.

RESULTS

For the VEGF +405C>G polymorphism, we observed significantly increased frequency of GG genotype in cases as compared to controls and strong association of +405GG genotype was observed with three fold risk for breast cancer (OR=3.07; 95%CI 1.41-6.65; p=0.003). For the +936C>T polymorphism, significant associations of CT and combined CT+TT genotypes were observed with elevated risk of breast cancer (p=0.021; 0.023). The combined genotype combinations of GG-CC and GG- CT of +405C>G and +936C>T polymorphisms were found to be significantly associated with increased risk of breast cancer (p=0.04; 0.0064).

CONCLUSIONS

The findings of the present study indicated significant associations of VEGF +936C>T and +405C>G polymorphisms with increased breast cancer risk in patients from Punjab, North India.

Correlations between the time-intensity parameters of contrast-enhanced ultrasound and clinical prognosis of hepatocellular carcinoma

PURPOSE

The purpose of the study was to detect the correlation between the time-intensity parameters of contrast-enhanced ultrasound (CEUS) and the clinical prognosis of hepatocellular carcinoma (HCC).

METHODS

A total of 73 HCC patients were analyzed with the time-intensity curve of CEUS. The expression of vascular endothelial factor (VEGF) and CD34 in different differentiation-staged HCC specimens was observed using immunohistochemistry.

RESULTS

A positive correlation was found between the VEGF expression and microvessel density. The time-intensity parameters were not correlated with the HCC size.

CONCLUSIONS

CEUS time-intensity parameters are inducive for assessing the prognosis of HCC with revealed intratumoral microvessel perfusion in different differentiation stages.

Update on the use of defibrotide

INTRODUCTION

Defibrotide is a polydisperse oligonucleotide obtained from porcine intestinal mucosa and prepared by controlled depolymerization of DNA. It is a nucleic acid polymer, predominantly single-stranded, which has anti-ischemic and anti-thrombotic properties.

AREAS COVERED

The efficacy and safety of defibrotide in the treatment of veno-occlusive disease (VOD) occurring after high-dose chemotherapy and hematopoietic stem-cell transplantation is now well established in Phase II - III trials. A recent randomized, Phase III trial in pediatric patients has also demonstrated its role in the prevention of VOD. Preclinical studies reported the inhibitory effects of defibrotide on myeloma cells' growth through an antiangiogenic action and a regulation of the tumor-microenvironment interactions. A recent Phase II trial underlines the efficacy and safety of defibrotide-thalidomide-melphalan combination in the treatment of relapsed/refractory multiple myeloma.

EXPERT OPINION

Defibrotide may be effective in the prophylaxis and the treatment of veno-occlusive disease. Recent experimental results suggest that defibrotide may belong to the new generation of anti-cancer drugs that can prevent tumor angiogenesis. In multiple myeloma, defibrotide may overcome the prothrombotic effect of thalidomide on endothelial cells. Further preclinical and clinical investigations are needed to assess the precise role of defibrotide in the treatment of patients with multiple myeloma.

Breast cancer genomics based on biobanks

Attempts to find genes contribution to complex diseases, such as cancer, require new study designs which incorporate an efficient use of population resources and modern genotyping technologies. We describe here two approaches, used by us for the study of breast cancer, both of which take the use of biobanks. One uses a cancer registry as a source of case information, which is then linked to a biobank on blood DNA. The biobank provides also samples from matched controls. After genotyping, clinical data are retrieved from hospital records, and the results can be presented for genotype-specific cancer risks, or similarly for genotype-specific clinical and survival parameters. The second approach uses registered data on cancer in families or among twins. On defined groups of patients, paraffin tissue is collected by contacting the pathology departments of the hospitals where the patients were diagnosed. Tumor and healthy tissue is prepared and used for mutation, the loss of heterozygosity, or copy number analysis. We believe that in the era of whole-genome genotyping technologies, the importance of well-characterized sample sets cannot be overemphasized. Samples rather than technologies limit the rate of gene discovery in complex diseases.

Significance of AEG-1 expression in correlation with VEGF, microvessel density and clinicopathological characteristics in triple-negative breast cancer

PURPOSE

Our study is to examine astrocyte-elevated gene-1 (AEG-1) expression in triple-negative breast cancer and to determine whether it is associated with vascular endothelial growth factor (VEGF), microvessel density (MVD), clinicopathological parameters and poor survival.

METHODS

Specimens from 125 patients with triple-negative breast cancers were investigated by immunohistochemistry for MVD, AEG-1 and VEGF expression. Correlations between the expression of AEG-1, VEGF, MVD, and various clinicopathological factors including survival status were studied.

RESULTS

AEG-1 and VEGF were highly expressed in 56.8% and 52.8% of triple-negative breast cancer patients, respectively. The intensity of AEG-1 was gradually up-regulated from VEGF-MVD-low, VEGF-high, or MVD-high to VEGF-MVD-high tissues using Western blot analysis. Statistically significant correlation was found among AEG-1 and VEGF, and MVD. Moreover, AEG-1 expression was correlated with clinical stage, lymphatic venous invasion, lymph nodal metastasis, tumor size, Ki67, and recurrence. Patients with AEG-1 high-expression showed far lower disease-free survival (DFS) and overall survival (OS) rates than those with AEG-1 low-expression. For VEGF and MVD, there were similar results in these patients. Only AEG-1 expression and tumor size were independent prognostic factors for both DFS and OS by multivariate analysis. However, the prognostic impact of tumor size was not as strong as that of AEG-1.

CONCLUSIONS

AEG-1 expression may be related with tumor angiogenesis and progression and is a valuable prognostic factor in patients with triple-negative breast cancer.

The experimental design as practical approach to develop and optimize a formulation of peptide-loaded liposomes

To investigate the encapsulation of Print 3G, a peptidic agent that could reduce the angiogenic development of breast tumors, pegylated liposomes used as intravenous vectors were studied and characterized. Recently, the path of liposomes has been explored with success to improve the pharmacological properties of peptidic drugs and to stabilize them. In this study, loaded unilamellar vesicles composed of SPC:CHOL:mPEG2000-DSPE (47:47:6) were prepared by the hydration of lipid film technique. An HPLC method was developed and validated for the determination of Print 3G to calculate its encapsulation efficiency. Observed Print 3G adsorption on different materials employed during liposome preparation (such as glass beads, tubing, and connections for extrusion) led to the modification of the manufacturing method. The freeze-thawing technique was used to enhance the amount of Print 3G encapsulated into blank liposomes prepared using the hydration of lipid film procedure. Many factors may influence peptide entrapment, namely the number of freeze-thawing cycles, the lipid concentration, the peptide concentration, and the mixing time. Consequently, a design of experiments was performed to obtain the best encapsulation efficiency while minimizing the number of experiments. The lipid concentration and the number of freeze-thawing cycles were identified as the positive factors influencing the encapsulation. As a result of the optimization, an optimum was found and encapsulation efficiencies were improved from around 30% to 63%. Liposome integrity was evaluated by photon correlation spectroscopy and freeze-fracture electron microscopy to ensure that the selected formulation possesses the required properties to be a potential candidate for further in vitro and in vivo experiments.

Significance of vascular endothelial growth factor expression and microvessel density in gastric cancer

AIM: To detect the correlations among vascular endothelial growth factor (VEGF) expression, microvessel density (MVD) and multiple pathological parameters in gastric cancer and analyze the significance of VEGF expression and MVD in patients with gastric cancer.

METHODS: A total of 169 patients with gastric cancer were retrospectively analyzed. The expression of VEGF and CD34 in gastric cancer specimens was detected by immunohistochemistry. The correlations among VEGF expression, MVD, and prognostic parameters were then analyzed.

RESULTS: A positive correlation was noted between VEGF expression and MVD in gastric carcinoma (P = 0.0053). Both VEGF expression and MVD were associated with tumor invasion, lymph node metastasis and TNM stage. The five-year disease-free survival and overall survival were lower in patients with tumors positive for VEGF than in those with tumors negative for VEGF (38.8% vs 57.1% and 35.3% vs 54.8%, respectively; both P < 0.01). The five-year disease-free survival and overall survival were lower in patients with tumors having high MVD score (> 5) than in patients with tumors having low MVD score (35.3% vs 53.9% and 23.5% vs 49.3%, both P < 0.05).

CONCLUSION: VEGF expression is closely associated with tumor angiogenesis and progression in gastric cancer. VEGF expression, MDV and tumor site are valuable parameters for predicting the prognosis of gastric cancer.

Insights into defibrotide: an updated review

Defibrotide is a polydisperse oligonucleotide with antiatherosclerotic, anti-inflammatory, anti-ischaemic, pro-fibrinolytic and antithrombotic actions without significant systemic anticoagulant effects. It has been used in the treatment of various cardiovascular disorders, and especially in endothelial complications of allogeneic stem-cell transplantation. We reviewed the published work for the mechanism of action and clinical use of defibrotide to consolidate data and to describe new applications of this drug. We reviewed the most relevant papers on defibrotide published from November 1982 to January 2008. (selected through PubMed), and used recent meeting abstracts as sources for this review. Reports have suggested that defibrotide has clinical efficacy for treatment and prophylaxis of hepatic sinusoidal obstruction syndrome occurring after stem-cell transplantation. Animal models have clearly shown the potential antineoplastic effect of this drug. Further clinical investigations are needed to clarify this new application.

IL-17 expression by breast-cancer-associated macrophages: IL-17 promotes invasiveness of breast cancer cell lines

Introduction

IL-17 plays an important role in autoimmunity, promoting autoimmunity, inflammation and invasion in multiple sclerosis, rheumatoid arthritis and type I diabetes. The role of IL-17 in cancer is unclear, however, as there are few studies examining IL-17 protein expression in cancer. We therefore examined IL-17 protein expression in human breast cancer and modelled its potential biological significance in vitro.

Methods

Immunohistochemistry was used to determine IL-17 expression in breast cancers. Matrigel invasion assays were employed to examine the effect of IL-17 on cancer cell invasion by a panel of breast cancer cell lines. The role of matrix metalloproteinases (MMPs) was investigated with selective antagonists and immunoassays for MMP-2, MMP-3, MMP-9 and tissue inhibitor of MMP.

Results

IL-17-expressing cells with macrophage morphology were identified in the peritumoural area of a proportion of patients (8/19 patients). Macrophages were confirmed by CD68 staining on serial sections. With the exception of occasional lymphocytes, one patient with rare multinucleate giant cells and one patient with occasional expression of IL-17 in tumour cells, no other IL-17-positive cells were detected. Addition of IL-17 to cell lines in vitro stimulated marked invasion of Matrigel. In contrast, IL-17 did not promote the invasion of MCF7 or T47D cell lines. Invasion was initially thought to be dependent on MMPs, as evidenced by the broad-spectrum MMP inhibitor GM6001 and selective antagonists of MMP-2/MMP-9 and MMP-3. Measurement of MMP-2, MMP-3 and MMP-9, and tissue inhibitor of MMP 1 secretion, failed to reveal any changes in expression following IL-17 exposure. In contrast, TNF promoted secretion of MMPs but IL-17 did not augment TNF, indicating that IL-17 acts via an independent mechanism.

Conclusions

The present study is the first to describe in situ expression of IL-17 protein in human breast tumours and to propose a direct association between IL-17 and breast cancer invasion. The precise effectors of IL-17-dependent invasion remain to be characterised but could include a range of proteases such as a disintegrin and metalloproteinase protein or astacins. Nevertheless, this work identifies a novel potential mechanism for breast cancer invasion and tumour progression, the prognostic implication of which is currently under investigation.

Defibrotide: a review on clinical use and future development

BACKGROUND

Defibrotide is a deoxyribonucleic acid derivative that has been developed for the treatment of different vascular disorders.

OBJECTIVE

The authors reviewed the literature to give due representation to the spectrum of pharmacological properties and clinical application of this drug, evaluating consolidate and innovative application.

METHODS

The authors used PubMed from November 1982 to December 2007 and meeting abstracts (form American Society of Hematology Annual Meeting) with updated data as the sources for this review and selecting the most relevant papers when two or more articles covered the same point of interest.

CONCLUSIONS

Defibrotide has been used effectively in the treatment of endothelial complications of allogeneic stem cell transplantation and recent preclinical evidences suggest an antiangiogenic effect and an anticancer activity. Further in vivo and in vitro investigations are needed.

Prognostic significance of VEGF expression in correlation with COX-2, microvessel density, and clinicopathological characteristics in human gastric carcinoma

BACKGROUND

Many studies have shown that angiogenesis plays an important role in the process of cancer development and progression. Vascular endothelial growth factor (VEGF) has a potent angiogenic activity, and cyclooxygenase-2 (COX-2) supports angiogenesis by regulated production of angiogenic factors, including VEGF. The purpose of this study was to examine the expression of VEGF in combination with COX-2 and CD34, their correlation with various clinicopathological factors, and their prognostic significance in human gastric carcinoma.

METHODS

Specimens from 169 patients with different grade and stage gastric carcinoma were investigated by immunohistochemistry for COX-2 and VEGF expression. Tumor microvessel density was assessed with CD34 immunostaining. Correlations between the expression of VEGF, COX-2, CD34, and various clinicopathological factors were studied. The effect of these proteins on patient survival was determined.

RESULTS

COX-2 and VEGF were positively expressed in 36.7% and 50.3% of the patients, respectively. Positive correlation was found between VEGF and COX-2 and between VEGF and CD34. VEGF expression was correlated with depth of invasion; metastatic lymph nodes; lymphatic and venous invasion; and tumor, node, metastasis system stage. Patients with positive staining for VEGF showed far lower disease-free (64.9% vs. 81.3%) and overall (58.3% vs. 76.9%) survival rates than VEGF-negative patients. In multivariate analysis, only tumor location, depth of invasion, and lymph node metastasis were shown to be independent prognostic factors.

CONCLUSIONS

VEGF expression correlates with angiogenesis and tumor progression and is a valuable prognostic factor in patients with gastric carcinoma.

Blood Flow Indices by Doppler Ultrasonography Vary with Neoadjuvant Chemotherapy but Are Not Related to Plasma VEGF Levels in Locally Advanced Breast Cancer

OBJECTIVE

The aim of our study was to assess the quantity of blood flow to malignant tissue by color Doppler ultrasonography, its correlation with plasma vascular endothelial growth factor (VEGF) levels and response to neoadjuvant chemotherapy of patients with locally advanced and inflammatory breast carcinoma.

METHODS

We measured blood velocity at peak systole (PSV), end-diastolic velocity and resistivity index [RI = (PSV - end-diastolic velocity)/PSV] by Doppler ultrasonography in primary tumors and/or axillary lymph nodes of patients before and after 2-4 cycles of anthracycline-containing neoadjuvant chemotherapy and basal plasma VEGF levels.

RESULTS

Of 21 patients with a median age of 42 years (range 26-68), 16 (76.2%) were premenopausal. Median basal RI was 0.70 (interquartile range 0.68-0.78) and PSV was 24.2 cm/s (interquartile range 18.7-56.6). The median measured VEGF level was 231.5 pg/ml (interquartile range 187.5-345.5). After 2-4 cycles of chemotherapy, 13 patients (61.9%) had partial remission and 8 (38.1%) were stable. Median basal RI (0.70, interquartile range 0.68-0.78) significantly decreased to 0.66 (interquartile range 0.59-073) after chemotherapy (p = 0.043). There was a trend that the greater the shrinkage of the tumor with chemotherapy, the lower the RI (r = 0.70, p = 0.078).

CONCLUSION

The decrease in RI with chemotherapy, which means increased blood flow at diastole of the cardiac cycle into the tumoral tissue, may be related to decreased intratumoral pressure secondary to tumor shrinkage and may reflect a new type of response, that is vascular response.

Localized Functionalization of Individual Colloidal Carriers for Cell Targeting and Imaging

Fabricating drug particles for therapeutic delivery and imaging presents important challenges in the design of the particle surfaces. Drug nanoparticle surfaces are currently functionalized with site-specific targeting ligands, biocompatible polymers, or fluorophore-polymer conjugates for specific imaging. However, if these functionalizations were to be synthesized on the drug carrier in localized, nanoscale regions on the particle surface, new schemes of drug delivery could be realized. Here we describe the use of our particle lithography technique that enables the synthesis of individual colloidal carrier assemblies that can be imaged and targeted to integrin-expressing cells. We show localized adhesion specificity for cells expressing the target integrin followed by receptor-mediated endocytosis. With the addition of localized delivery by adding drug nanoparticles to a specific region on the particle surface, our colloidal carrier assemblies have the potential to target, deliver therapeutic agents to, sense, and image diseased endothelium.

Expression and prognostic impact of the protein tyrosine phosphatases PRL-1, PRL-2, and PRL-3 in breast cancer

The aim of this study was to investigate the expression of the protein tyrosine phosphatases (PTP) PRL-1, PRL-2, and PRL-3 in human breast cancer and to evaluate its clinical and prognostic significance. PRL-PTP mRNA expression was examined in malignant (n=7) and nonmalignant (n=7) cryoconserved breast tissue samples as well as in eight breast cancer cell lines by RT–PCR. Furthermore, protein expression of PRL-3 was analysed semiquantitatively by immunohistochemistry in ductal breast carcinoma in situ (n=135) and invasive breast cancer (n=147) by use of tissue microarray technology (TMA). In 24 lymph node-positive patients we selected the corresponding lymph node metastases for analysis of PRL-3 expression, and a validation set (n=99) of invasive breast cancer samples was examined. Staining results were correlated with clinicopathological parameters and long-term follow-up. PRL-3 mRNA expression was significantly higher in malignant compared to benign breast tissue. For PRL-1 and PRL-2 expression no significant differences were observed. Staining of TMAs showed PRL-3 expression in 85.9% ductal carcinoma in situ and 75.5% invasive breast carcinomas. Analysis of survival parameters revealed a shorter disease-free survival (DFS) in patients with PRL-3-positive carcinomas, and in particular a significantly shorter DFS in nodal-positive patients with PRL-3 overexpressing tumours as compared to PRL-3-negative breast carcinomas (66±7 months (95% CI, 52–80) vs 97±9 months (95% CI, 79–115); P=0.032). Moreover, we found a more frequent expression of PRL-3 in lymph node metastases as compared to the primary tumours (91.7 vs 66.7%; P=0.033). Our results suggest that PRL-3 might serve as a novel prognostic factor in breast cancer, which may help to predict an adverse disease outcome.

Polymorphisms in the KDR and POSTN Genes: Association with Breast Cancer Susceptibility and Prognosis

Angiogenesis is an important step in the development of cancer. Vascular endothelial growth factor is a major regulator of breast cancer angiogenesis, the effects of which are transmitted through the kinase domain receptor (KDR). Up-regulation of KDR by periostin (POSTN) induces angiogenesis. We screened the KDR and the POSTN genes for published single nucleotide polymorphisms (SNPs) and chose two SNPs in each gene for further analyses. We carried out a case-control study consisting of 412 familial and 912 unselected breast cancer cases together with ethnically and geographically selected controls. Genotype, haplotype and genotype combination analyses were carried out to evaluate their effect on susceptibility to and prognosis of breast cancer. A haplotype in the POSTN gene was associated with an increased risk even after correction for multiple comparisons. Nominal associations between the SNPs and prognostic indicators were also observed. Tumors of the KDR 472His allele carriers were less often progesterone receptor negative according to both genotype and haplotype analyses (OR 0.61, 95%CI 0.40-0.92 and OR 0.60, 95%CI 0.40-0.91, respectively). The POSTN -33G allele carriers had more often high grade and estrogen receptor negative tumors (OR 1.75, 95%CI 1.02-3.01 and OR 1.70, 95%CI 1.04-2.78, respectively). The overall and cancer specific survival after 15 years of follow-up was more than 75%, and it did not depend on the genotype. Although a major effect of the SNPs in the KDR and the POSTN genes on breast cancer susceptibility and prognosis was excluded, the effect of the POSTN C-33G SNP on prognosis needs further characterization.

Powerful prognostic stratification by [18F]fluorodeoxyglucose positron emission tomography in patients with metastatic breast cancer treated with high-dose chemotherapy

PURPOSE

This study examines the use of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the evaluation of the therapeutic response for patients treated with high-dose chemotherapy (HDC) with autologous stem cell transplantation for metastatic breast cancer (MBC) focusing on prognostic stratification.

PATIENTS AND METHODS

Forty-seven patients with MBC were treated with a maximum of three cycles of HDC. Therapeutic response was assessed with conventional imaging (CImg; including a computed tomography in all cases and ultrasound, mammography, and bone scanning as clinically indicated) and by FDG-PET study performed after the last cycle of HDC. Parameters analyzed for predicting survival were FDG-PET and CImg results, pattern of disease, prior treatment, and HDC regimen.

RESULTS

Complete responses were observed in 16 patients (37%) with CImg and 34 patients (72%) with FDG-PET. The FDG-PET result was the most powerful and independent predictor of survival; patients with a negative post-treatment FDG-PET had a longer median survival than patients with a positive FDG-PET (24 months v 10 months; P < .001). By multivariate analysis the relative risk (RR) of death was higher in patients with FDG-PET-positive disease (RR, 5.3), prior anthracycline treatment (RR, 3.3), or with visceral metastasis (RR, 2.4).

CONCLUSION

A single FDG-PET study performed after completion of HDC for MBC can powerfully stratify for survival. This may have implications for how we should assess outcome after conventional-dose therapy for MBC and warrants additional study.

Rhodamine-RCA in vivo labeling guided laser capture microdissection of cancer functional angiogenic vessels in a murine squamous cell carcinoma mouse model

Background

Cancer growth, invasion and metastasis are highly related to tumor-associated neovasculature. The presence and progression of endothelial cells in cancer is chaotic, unorganized, and angiogenic vessels are less functional. Therefore, not all markers appearing on the chaotic endothelial cells are accessible if a drug is given through the vascular route. Identifying endothelial cell markers from functional cancer angiogenic vessels will indicate the accessibility and potential efficacy of vascular targeted therapies.

Results

In order to quickly and effectively identify endothelial cell markers on the functional and accessible tumor vessels, we developed a novel technique by which tumor angiogenic vessels are labeled in vivo followed by Laser Capture Microdissection of microscopically isolated endothelial cells for genomic screening. Female C3H mice (N = 5) with established SCCVII tumors were treated with Rhodamine-RCA lectin by tail vein injection, and after fluorescence microscopy showed a successful vasculature staining, LCM was then performed on frozen section tissue using the PixCell II instrument with CapSure HS caps under the Rhodamine filter. By this approach, the fluorescent angiogenic endothelial cells were successfully picked up. As a result, the total RNA concentration increased from an average of 33.4 ng/ul +/- 24.3 (mean +/- S.D.) to 1913.4 ng/ul +/- 164. Relatively pure RNA was retrieved from both endothelial and epithelial cells as indicated by the 260/280 ratios (range 2.22–2.47). RT-PCR and gene electrophoresis successfully detected CD31 and Beta-Actin molecules with minimal Keratin 19 expression, which served as the negative control.

Conclusion

Our present study demonstrates that in vivo Rhodamine RCA angiogenic vessel labeling provided a practical approach to effectively guide functional endothelial cell isolation by laser capture microdissection with fluorescent microscopy, resulting in high quality RNA and pure samples of endothelial cells pooled for detecting genomic expression.

Nitric oxide regulates angiogenesis through a functional switch involving thrombospondin-1

Nitric oxide (NO) donors have been shown to stimulate and inhibit the proliferation, migration, and differentiation of endothelial cells in vitro and angiogenesis in vivo. Recently, we have shown distinct thresholds for NO to regulate p53-Ser-15P, phosphorylated extracellular signal-regulated kinase (pERK), and hypoxia inducible factor 1alpha in tumor cells. Because these signaling pathways also promote the growth and survival of endothelial cells, we examined their roles in angiogenic responses of venous endothelial cells and vascular outgrowth of muscle explants elicited by NO. An additional protein involved in the regulation of angiogenesis is thrombospondin-1 (TSP1), a matricellular glycoprotein known to influence adhesion, migration, and proliferation of endothelial cells. Here we demonstrate a triphasic regulation of TSP1 mediated by a slow and prolonged release of NO that depends on ERK phosphorylation. Under conditions of 5% serum, a 24-h exposure of NO donor (0.1-1,000 microM) mediated a triphasic response in the expression of TSP1 protein: decreasing at 0.1 microM, rebounding at 100 microM, and decreasing again at 1,000 microM. Under the same conditions, we observed a dose-dependent increase in P53 phosphorylation and inverse biphasic responses of pERK and mitogen-activated protein kinase phosphatase-1. Both the growth-stimulating activity of low-dose NO for endothelial cells and suppression of TSP1 expression were ERK-dependent. Conversely, exogenous TSP1 suppressed NO-mediated pERK. These results suggest that dose-dependent positive- and negative-feedback loops exist between NO and TSP1. Limiting TSP1 expression by positive feedback through the ERK mitogen-activated protein kinase pathway may facilitate switching to a proangiogenic state at low doses of NO.

Vascular endothelial growth factor polymorphisms in relation to breast cancer development and prognosis

PURPOSE

Angiogenesis is a necessary step in tumor growth and metastasis. Vascular endothelial growth factor (VEGF) is a major mediator of breast cancer angiogenesis. Therefore, we investigated the association of polymorphisms in the VEGF gene with breast cancer risk and prognostic characteristics of the tumors in a large case-control study.

EXPERIMENTAL DESIGN

We examined three polymorphisms in the VEGF gene (-2578C/A, -1154G/A, and +936C/T) in 571 familial breast cancer cases from Poland and Germany and -2578C/A, -634G/C, and +936C/T polymorphisms in 974 unselected breast cancer cases from Sweden together with ethnically and geographically selected controls.

RESULTS

None of the polymorphisms or any haplotype was significantly associated with either familial or unselected breast cancers. Our study suggests that the +936C/T polymorphism is unlikely to be associated with breast cancer. We also analyzed the unselected cases for genotypes or haplotypes that associated with tumor characteristics. The -634CC genotype and the -2578/-634 CC haplotype were significantly associated with high tumor aggressiveness (large tumor size and high histologic grade, P < 0.01) and the -2578AA genotype and the -2578/-634 AG haplotype with low histologic grade tumors (P = 0.04). The genotypes and haplotypes were not related with other tumor characteristics such as regional or distant metastasis, stage at diagnosis, or estrogen or progesterone receptor status.

CONCLUSIONS

Although none of the polymorphisms studied in the VEGF gene was found to influence susceptibility to breast cancer significantly, some of the VEGF genotypes and haplotypes may influence tumor growth through an altered expression of VEGF and tumor angiogenesis.