The prognostic value of vascular endothelial growth factors (VEGFs)-A and -B and their receptor, VEGFR-1, in invasive breast carcinoma

An Anti-VEGF-B Antibody Reduces Abnormal Tumor Vasculature and Enhances the Effects of Chemotherapy

The vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are key regulators of blood vessel formation, including in tumors, where their deregulated function can promote the production of aberrant, leaky blood vessels, supporting tumor development. Here we investigated the VEGFR1 ligand VEGF-B, which we demonstrate to be expressed in tumor cells and in tumor stroma and vasculature across a range of tumor types. We examined the anti-VEGF-B-specific monoclonal antibody 2H10 in preclinical xenograft models of breast and colorectal cancer, in comparison with the anti-VEGF-A antibody bevacizumab. Similar to bevacizumab, 2H10 therapy was associated with changes in tumor blood vessels and intra-tumoral diffusion consistent with normalization of the tumor vasculature. Accordingly, treatment resulted in partial inhibition of tumor growth, and significantly improved the response to chemotherapy. Our studies indicate the importance of VEGF-B in tumor growth, and the potential of specific anti-VEGF-B treatment to inhibit tumor development, alone or in combination with established chemotherapies.

Vascular Endothelial Growth Factor Expression by Immunohistochemistry as a Possible Indicator of Prognosis in Invasive Breast Carcinoma of No Special Type

Context

Angiogenesis, the formation of new blood vessels from preexisting vascular network, is essential for tumor growth and spread. Vascular endothelial growth factor (VEGF) is a potent angiogenic growth factor.

Aims

To assess the expression of VEGF in invasive carcinoma of no special type and its correlation with all the known prognostic factors of breast carcinoma.

Settings and Design

Descriptive.

Materials and Methods

Mastectomy specimens were studied noting the clinical details. The formalin-fixed tissues were subjected to routine processing and hematoxylin and eosin sections and studied extensively for all the histological prognostic factors. Representative sections from each case with the tumor were subjected to immunohistochemistry (IHC) staining with VEGF, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/neu) antibodies.

Statistical Analysis Used

Descriptive statistics, Chi-square tests, contingency table analysis using SPSS for Windows.

Results

One hundred and twelve cases of invasive carcinoma of special type were studied to evaluate various clinicopathological parameters. The association of VEGF with clinicopathological parameters and all the known prognostic factors was studied to note its significance. VEGF overexpression was observed in 69% of the cases. It was noted that larger tumor size, higher histological grade, lymphovascular invasion, nodal involvement, tumor necrosis, high microvessel density, ER negativity, PR negativity, and HER2/neu positivity had a significant statistical association with VEGF overexpression.

Conclusions

We conclude that incorporating VEGF as a biomarker along with the known factors into a prognostic index will not only help predict clinical outcome more accurately, but also determines the patient who can be benefited with combinational therapy including anti-VEGF factors.

Low-grade mammary gland tumours in dogs have greater VEGF-A and BMP2 immunostaining and higher CD31 blood vessel density

Tumor angiogenesis is an important process in tumor growth, and different molecules are involved in its regulation including VEGF-A, BMP2, and CD31, which can be considered possible prognostic markers. The aim of this study was to verify whether the VEGF-A and BMP2 immunostaining area, and microvascular density (MVD) might be associated with the degree of malignancy in malignant mammary neoplasms of dogs. For this purpose, samples of mammary malignancies from female dogs embedded in wax were used and separated into four main histomorphological types: tubulopapillary carcinomas, solid, complex, and carcinosarcoma, which were separated based on high and low degrees of malignancy. Immunohistochemical analysis was performed on tissue microarray blocks using anti-CD31 antibodies for evaluation of MVD and vascular lumen area, and with anti-VEGF-A and anti-BMP2 to determine the immunostaining area using the DAKO EnVision™ FLEX+ kit. MVD and vascular lumen area were higher in tubulopapillary carcinomas as were the areas stained by VEGF-A and BMP2. Immunostaining for CD31 was higher in low-grade carcinomas as well as in areas immunostained by VEGF-A and BMP2. There was a positive correlation between VEGF and BMP2 in high (r = 0.556, p < 0.0001) and low-grade (r = 0.287, p<0.0001) carcinomas and between MVD and VEGF-A in low-grade carcinomas (r = 0.267, p = 0.0064). Thus, the markers evaluated showed greater immunostaining in canine mammary tumors with a lower degree of malignancy.

Plasma Levels and Diagnostic Utility of VEGF in a Three-Year Follow-Up of Patients with Breast Cancer

Breast cancer is the most common malignancy in women globally. The increasing worldwide incidence of this type of cancer illustrates the challenge it represents for healthcare providers. Therefore, new tumor markers are constantly being sought. The aim of this study was to assess plasma concentrations and the diagnostic power of VEGF in 100 patients with early-stage breast cancer, both before and after surgical treatment and during a three-year follow-up. The control groups included 50 subjects with benign breast tumors (fibroadenoma) and 50 healthy women. The VEGF concentration was determined using enzyme-linked immunosorbent assay (ELISA) and the CA 15-3 concentration was determined by chemiluminescent microparticle immunoassay (CMIA). We observed significantly higher preoperative plasma concentrations of VEGF and CA 15-3 in patients with breast cancer. VEGF, similar to CA 15-3, demonstrated high diagnostic utility in the assessment of the long-term efficacy of surgical removal of the tumor. Determinations of VEGF had the highest diagnostic usefulness in the detection of breast cancer recurrence (SE 40%, SP 92%, PPV 67%, NPV 79%). Additionally, the highest values of SE, NPV and AUC were observed during the combined analysis with CA 15-3 (60%; 84%; 0.7074, respectively). Our study suggests a promising diagnostic utility of VEGF in the early stages of breast cancer and in the evaluation of the efficacy of the surgical treatment of breast cancer as well as the detection of breast cancer recurrence, particularly in a combined analysis with CA 15-3 as a new diagnostic panel.

Modulating the Crosstalk between the Tumor and the Microenvironment Using SiRNA: A Flexible Strategy for Breast Cancer Treatment

Simple Summary

With this review we aimed to collect the most relevant scientific findings regarding siRNA therapeutic tools against breast cancer microenvironment. Remarkably, breast cancer treatments have been redirected towards the tumor microenvironment components, mainly involved in patients’ relapse and pharmacological resistance. Therefore, siRNAs represent a promising strategy to jeopardize the tumor microenvironment interplay thanks to their non-toxic and specific effects.

Abstract

Tumorigenesis is a complex and multistep process in which sequential mutations in oncogenes and tumor-suppressor genes result in enhanced proliferation and apoptosis escape. Over the past decades, several studies have provided evidence that tumors are more than merely a mass of malignant cancer cells, with the tumor microenvironment (TME) also contributing to cancer progression. For this reason, the focus of cancer research in recent years has shifted from the malignant cancer cell itself to the TME and its interactions. Since the TME actively participates in tumor progression, therapeutic strategies targeting it have created great interest. In this context, much attention has been paid to the potential application of small interfering RNA (siRNA), a class of non-coding RNA that has the ability to downregulate the expression of target genes in a sequence-specific way. This is paving the way for a novel therapeutic approach for the treatment of several diseases, including cancer. In this review, we describe recent efforts in developing siRNA therapeutics for the treatment of breast cancer, with particular emphasis on TME regulation. We focus on studies that adapt siRNA design to reprogram/re-educate the TME and eradicate the interplay between cancer cells and TME.

VEGFR1+ Metastasis-Associated Macrophages Contribute to Metastatic Angiogenesis and Influence Colorectal Cancer Patient Outcome

PURPOSE

To investigate the clinical relevance of macrophages in liver metastasis of colorectal cancer and their influence on angiogenesis and patient survival. Moreover to evaluate specific blood monocytes as markers of disease recurrence.Experimental design: In a mouse model with spontaneous liver metastasis, the angiogenic characteristics of tumor- and metastasis (MAM)-associated macrophages were evaluated. Macrophages and the vasculature from 130 primary tumor (pTU) and 123 patients with liver metastasis were assessed. In vivo and in human samples, the clinical relevance of macrophage VEGFR1 expression was analyzed. Blood samples from patients (n = 157, 80 pTU and 77 liver metastasis) were analyzed for assessing VEGFR1-positive (VEGFR1⁺) cells as suitable biomarkers of disease recurrence.

RESULTS

The number of macrophages positively correlated with vascularization in metastasis. Both in the murine model as well as in primary isolated human cells, a subpopulation of MAMs expressing VEGFR1 were found highly angiogenic. While VEGFR1 expression in pTU patients did not predict prognosis; high percentage of VEGFR1⁺ cells in liver metastasis was associated with worse patient outcome. Interestingly, VEGFR1⁺-circulating monocytes in blood samples from patients with liver metastasis not only predicted progression but also site of recurrence.

CONCLUSIONS

Our findings identify a new subset of proangiogenic VEGFR1⁺ MAMs in colorectal cancer that support metastatic growth and may become a liquid biomarker to predict disease recurrence in the liver.

Bifunctional Duocarmycin Analogues as Inhibitors of Protein Tyrosine Kinases

Bifunctional duocarmycin analogues are highly cytotoxic compounds that have been shown to be irreversible aldehyde dehydrogenase 1 inhibitors. Interestingly, cells with low aldehyde dehydrogenase 1 expression are also sensitive to bifunctional duocarmycin analogues, suggesting the existence of another target. Through in silico approaches, including principal component analysis, structure-similarity search, and docking calculations, protein tyrosine kinases, and especially the vascular endothelial growth factor receptor 2 (VEGFR-2), were predicted as targets of bifunctional duocarmycin analogues. Biochemical validation was performed in vitro, confirming the in silico results. Structural optimization was performed to mainly target VEGFR-2, but not aldehyde dehydrogenase 1. The optimized bifunctional duocarmycin analogue was synthesized. In vitro assays revealed this bifunctional duocarmycin analogue as a strong inhibitor of VEGFR-2, with low residual aldehyde dehydrogenase 1 activity. Altogether, studies revealed bifunctional duocarmycin analogues as a new class of naturally derived compounds that express a very high cytotoxicity to cancer cells overexpressing aldehyde dehydrogenase 1 as well as VEGFR-2.

Long-term response to first-line bevacizumab-based therapy in patients with metastatic breast cancer: results of the observational "LORENA" study

Background

Randomized controlled trials of the first-line combination of bevacizumab and chemotherapy in patients with metastatic breast cancer (MBC) have shown improvements in tumor response and progression-free survival (PFS).

Objective

The aim of this ambispective, observational study (LORENA) was to describe the clinical characteristics of long-term responders to bevacizumab-based therapy.

Patients and methods

This study consisted of a retrospective and a prospective phase. During the retrospective phase, patients with HER2-negative MBC who were treated with bevacizumab-based first-line therapy were included. During the prospective phase, patients with PFS of ≥12 months were treated according to routine clinical practice procedures. Overall survival (OS) and PFS were estimated using the Kaplan–Meier method. Univariate and multivariate analyses of prognostic factors were performed.

Results

In total, 148 women were included (median age: 50 years; range: 29–81 years). The mean duration of exposure to bevacizumab was 18 months. The majority of patients experienced objective response (complete: 23%; partial: 57%). Median PFS was 22.7 months and median OS was 58.2 months. In multivariate analyses, patients receiving maintenance hormonal therapy (MHT) had longer PFS (P=0.002; hazard ratio [HR] =1.8) and OS (P=0.009; HR=2.0), while patients not previously treated with taxanes had longer OS (P<0.0001; HR =3.3). No unexpected adverse events were observed.

Conclusion

The results of this study suggest, that among long-term responders, first-line bevacizumab-based therapy is more effective in patients who had not been previously treated with taxanes, and that MHT provides additional therapeutic benefits by extending PFS and OS.

Light-enhanced VEGF121/rGel: A tumor targeted modality with vascular and immune-mediated efficacy

Interactions between stromal cells and tumor cells pay a major role in cancer growth and progression. This is reflected in the composition of anticancer drugs which includes compounds directed towards the immune system and tumor-vasculature in addition to drugs aimed at the cancer cells themselves. Drug-based treatment regimens are currently designed to include compounds targeting the tumor stroma in addition to the cancer cells. Treatment limiting adverse effects remains, however, one of the major challenges for drug-based therapy and novel tolerable treatment modalities with diverse high efficacy on both tumor cells and stroma is therefore of high interest. It was hypothesized that the vascular targeted fusion toxin VEGF₁₂₁/rGel in combination with the intracellular drug delivery technology photochemical internalization (PCI) stimulate direct cancer parenchymal cell death in addition to inhibition of tumor perfusion, and that an immune mediated response is relevant for treatment outcome. The aim of the present study was therefore to elucidate the anticancer mechanisms of VEGF₁₂₁/rGel-PCI. In contrast to VEGF₁₂₁/rGel monotherapy, VEGF₁₂₁/rGel-PCI was found to mediate its effect through VEGFR1 and VEGFR2, and a targeted treatment effect was shown on two VEGFR1 expressing cancer cell lines. A cancer parenchymal treatment effect was further indicated on H&E stains of CT26-CL25 and 4 T1 tumors. VEGF₁₂₁/rGel-PCI was shown, by dynamic contrast enhanced MRI, to induce a sustained inhibition of tumor perfusion in both tumor models. A 50% complete remission (CR) of CT26.CL25 colon carcinoma allografts was found in immunocompetent mice while no CR was detected in CT26.CL25 bearing athymic mice. In conclusion, the present report indicate VEGF₁₂₁/rGel -PCI as a treatment modality with multimodal tumor targeted efficacy that should be further developed towards clinical utilization.

Combination antitumor immunotherapy with VEGF and PIGF siRNA via systemic delivery of multi-functionalized nanoparticles to tumor-associated macrophages and breast cancer cells

Given that vascular endothelial growth factor (VEGF) and placental growth factor (PIGF), over-expressed in breast cancer cells and M2-like tumor-associated macrophages (M2-TAMs) within tumor microenvironment (TME), work synergistically and independently in mediating tumor progression and immunosuppression, combinatorial immune-based approaches targeting them are expected to be a potent therapeutic modality for patients. Here, polyethylene glycol (PEG) and mannose doubly modified trimethyl chitosan (PEG = MT) along with citraconic anhydride grafted poly (allylamine hydrochloride) (PC)-based nanoparticles (NPs) (PEG = MT/PC NPs) with dual pH-responsiveness were developed to deliver VEGF siRNA (siVEGF)/PIGF siRNA (siPIGF) to both M2-TAMs and breast cancer cells for antitumor immunotherapy. With prolonged blood circulation and intelligent pH-sensitivity, PEG = MT/PC NPs were highly accumulated in tumor tissues and then internalized in M2-TAMs and breast cancer cells via mannose-mediated active targeting and passive targeting, respectively. With the charge-reversal of PC, PEG = MT/PC NPs presented effective endosomal/lysosomal escape and intracellular siRNA release, resulting in efficient gene silencing. Due to the synergism between siVEGF and siPIGF in anti-proliferation of tumor cells and reversal of the TME from pro-oncogenic to anti-tumoral, PEG = MT/PC/siVEGF/siPIGF NPs (PEG = MT/PC/siV-P NPs) exerted robust suppression of breast tumor growth and lung metastasis. This combination strategy may provide a promising alternative for breast cancer therapy.

Associations of angiogenesis-related proteins with specific prognostic factors, breast cancer subtypes and survival outcome in early-stage breast cancer patients. A Hellenic Cooperative Oncology Group (HeCOG) trial

Several studies support an important role of angiogenesis in breast cancer growth and metastasis. The main objectives of the study were to investigate the immunohistochemical expression of vascular endothelial growth factor (VEGF) family ligands (VEGF-A and VEGF-C) and receptors (VEGFR1, VEGFR2 and VEGFR3) in breast cancer and their associations with clinicopathological parameters, cancer subtypes/subgroups and patient outcome. Formalin-fixed paraffin-embedded tumor tissue samples were collected from early-stage breast cancer patients treated with anthracycline-based chemotherapy within a randomized trial. Immunohistochemistry was performed on serial 2.5 μm thick tissue sections from tissue microarray blocks. High VEGF-A, VEGF-C, VEGFR1, VEGFR2 and VEGFR3 protein expression was observed in 11.8% (N = 87), 80.8% (N = 585), 28.1% (N = 202), 64.6% (N = 359) and 71.8% (N = 517) of the cases, respectively. Significant associations were observed among all proteins (all p-values <0.05), with the exception of the one between VEGF-C and VEGFR1 (chi-square test, p = 0.15). Tumors with high VEGF-A protein expression, as compared to tumors with low expression were more frequently ER/PgR-negative (33.3% vs. 20.8%, chi-square test, p = 0.009) and HER2-positive (44.8% vs. 20.6%, p<0.001). In addition, tumors with high VEGFR1 expression, were more frequently HER2-positive (32.8% vs. 19.6%, p<0.001), while tumors with high VEGFR3 expression were more frequently ER/PgR-negative (24.9% vs. 17.0%, p = 0.024) and HER2-positive (26.9% vs. 14.8%, p = 0.001). High VEGF-A and VEGF-C protein expression was associated with increased DFS in the entire cohort (HR = 0.57, 95% CI 0.36–0.92, Wald’s p = 0.020 and HR = 0.71, 95% CI 0.52–0.96, p = 0.025, respectively), as well as in specific subtypes/subgroups, such as HER2-positive (VEGF-A, HR = 0.32, 95% CI 0.14–0.74, p = 0.008) and triple-negative (VEGF-C, HR = 0.44, 95% CI 0.21–0.91, p = 0.027) patients. High vs. low VEGFR1 expression was an unfavorable factor for DFS in triple-negative patients (HR = 2.74, 95% CI 1.26–5.98, p = 0.011), whereas the opposite was observed among the ER/PgR-positive patients (HR = 0.69, 95% CI 0.48–0.98, p = 0.041). Regarding OS, high VEGF-C protein expression was associated with increased OS in the entire cohort (HR = 0.64, 95% CI 0.46–0.89, Wald’s p = 0.008), as well as in in specific subtypes/subgroups, such as ER/PgR-negative (HR = 0.37, 95% CI 0.20–0.71, p = 0.003) and triple-negative (HR = 0.42, 95% CI 0.19–0.90, p = 0.026) patients. In conclusion, high expression of angiogenesis-related proteins is associated with adverse clinicopathological parameters in early-stage breast cancer patients and may be surrogate markers of biologically distinct subgroups of ER/PgR-negative or triple-negative tumors with superior outcome. Further validation of our findings in independent cohorts is needed.

Peptide ligand-modified nanomedicines for targeting cells at the tumor microenvironment

Since their initial discovery more than 30years ago, tumor-homing peptides have become an increasingly useful tool for targeted delivery of therapeutic and diagnostic agents into tumors. Today, it is well accepted that cells at the tumor microenvironment (TME) contribute in many ways to cancer development and progression. Tumor-homing peptide-decorated nanomedicines can interact specifically with surface receptors expressed on cells in the TME, improve cellular uptake of nanomedicines by target cells, and impair tumor growth and progression. Moreover, peptide ligand-modified nanomedicines can potentially accumulate in the target tissue at higher concentrations than would small conjugates, thus increasing overall target tissue exposure to the therapeutic agent, enhance therapeutic efficacy and reduce side effects. This review describes the most studied peptide ligands aimed at targeting cells in the TME, discusses major obstacles and principles in the design of ligands for drug targeting and provides an overview of homing peptides in ligand-targeted nanomedicines that are currently in development for cancer therapy and diagnosis.

Interface between breast cancer cells and the tumor microenvironment using platelet-rich plasma to promote tumor angiogenesis - influence of platelets and fibrin bundles on the behavior of breast tumor cells

Cancer progression is associated with an evolving tissue interface of direct epithelial-tumor microenvironment interactions. In biopsies of human breast tumors, extensive alterations in molecular pathways are correlated with cancer staging on both sides of the tumor-stroma interface. These interactions provide a pivotal paracrine signaling to induce malignant phenotype transition, the epithelial-mesenchymal transition (EMT). We explored how the direct contact between platelets-fibrin bundles primes metastasis using platelet-rich plasma (PRP) as a source of growth factors and mimics the provisional fibrin matrix between actively growing breast cancer cells and the tumor stroma. We have demonstrated PRP functions, modulating cell proliferation that is tumor-subtype and cancer cell-type-specific. Epithelial and stromal primary cells were prepared from breast cancer biopsies from 21 women with different cancer subtypes. Cells supplemented with PRP were immunoblotted with anti-phospho and total Src-Tyr-416, FAK-Try-925, E-cadherin, N-cadherin, TGF-β, Smad2, and Snail monoclonal antibodies. Breast tumor cells from luminal B and HER2 subtypes showed the most malignant profiles and the expression of thrombin and other classes of proteases at levels that were detectable through FRET peptide libraries. The angiogenesis process was investigated in the interface obtained between platelet-fibrin-breast tumor cells co-cultured with HUVEC cells. Luminal B and HER2 cells showed robust endothelial cell capillary-like tubes ex vivo. The studied interface contributes to the attachment of endothelial cells, provides a source of growth factors, and is a solid substrate. Thus, replacement of FBS supplementation with PRP supplementation represents an efficient and simple approach for mimicking the real multifactorial tumor microenvironment.

Resveratrol attenuates myocardial ischemia/reperfusion injury through up-regulation of vascular endothelial growth factor B

The objective was to examine the protective effect of resveratrol (RSV) on myocardial ischemia/reperfusion (IR) injury and whether the mechanism was related to vascular endothelial growth factor B (VEGF-B) signaling pathway. Rat hearts were isolated for Langendorff perfusion test and H9c2 cells were used for in vitro assessments. RSV treatment significantly improved left ventricular function, inhibited CK-MB release, and reduced infarct size in comparison with IR group ex vivo. RSV treatment markedly decreased cell death and apoptosis of H9c2 cells during IR. We found that RSV was responsible for the up-regulation of VEGF-B mRNA and protein level, which caused the activation of Akt and the inhibition of GSK3β. Additionally, RSV prevented the generation of reactive oxygen species (ROS) by up-regulating the expression of MnSOD either in vitro or ex vivo. We also found that the inhibition of VEGF-B abolished the cardioprotective effect of RSV, increased apoptosis, and led to the down-regulation of phosphorylated Akt, GSK3β, and MnSOD in H9c2 cells. These results demonstrated that RSV was able to attenuate myocardial IR injury via promotion of VEGF-B/antioxidant signaling pathway. Therefore, the up-regulation of VEGF-B can be a promising modality for clinical myocardial IR injury therapy.

Association between VEGF-A, C and D expression and lymph node involvement in breast cancer: a meta-analysis

BACKGROUND

Metastasis is the primary cause of death in patients with breast cancer. Although VEGF-A, C and D are considered to be prime factors in lymph node metastasis in breast cancer, the published studies have conflicting conclusions.

METHODS

To resolve this conflict, we conducted a meta-analysis of 37 studies (n = 5,001 patients) evaluating the correlation between VEGF-A, C and D immunohistochemical expression and lymph node metastasis (LNM). The meta-analysis included 22 studies of VEGF-A, 17 of VEGF-C, and 6 of VEGF-D. The relationships between VEGF-A, C and D and clinicopathological parameters were also examined.

RESULTS

The results showed a significant association between VEGF-A or VEGF-C overexpression and LNM (risk ratio [RR] = 1.28 [95% CI 1.04-1.58], p = 0.02; and RR = 1.36 [95% CI 1.07-1.72], p = 0.01, respectively). Subgroup evaluation showed a significant association between VEGF-A, C and D overexpression and LNM when analyses were limited to Asian patients (RR = 1.78 [95% CI 1.28-2.46], p = 0.0005; RR = 1.38 [95% CI 1.04-1.84], p = 0.03, and RR = 2.62 [95% CI 1.35-5.09], p = 0.004, respectively). VEGF-A overexpression was significantly associated with lymph vessel invasion (RR = 1.86 [95% CI 1.33-2.60], p = 0.0003). Overexpression of VEGF-C or VEGF-D was significantly associated with HER-2 positivity (RR = 1.30 [95% CI 1.06-1.59], p = 0.01; and RR = 1.75 [95% CI 1.01-3.03], p = 0.05, respectively).

CONCLUSIONS

With some limitations, our meta-analysis indicated that VEGF-A and C could predict LNM in patients with breast cancer, particularly Asian patients.

Loss of membranous VEGFR1 expression is associated with an adverse phenotype and shortened survival in breast cancer

Angiogenesis is a key process in tumor growth and progression, which is controlled by vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs). In order to better understand the prevalence and prognostic value of VEGFR1 expression in breast cancer, a tissue microarray containing >2,100 breast cancer specimens, with clinical follow‑up data, was analyzed by immunohistochemistry using an antibody directed against the membrane‑bound full‑length receptor protein. The results demonstrated that membranous VEGFR1 staining was detected in all (5 of 5) normal breast specimens. In carcinoma specimens, membranous staining was negative in 3.1%, weak in 6.3%, moderate in 10.9%, and strong in 79.7% of the 1,630 interpretable tissues. Strong staining was significantly associated with estrogen receptor and progesterone receptor expression, but was inversely associated with advanced tumor stage (P=0.0431), high Bloom-Richardson-Ellis Score for Breast Cancer grade and low Ki67 labeling index (both P<0.0001). Cancers with moderate to strong (high) VEGFR1 expression were associated with significantly improved overall survival, as compared with tumors exhibiting negative or weak (low) expression (P=0.0015). This association was also detected in the subset of nodal‑positive cancers (P=0.0018), and in the subset of 185 patients who had received tamoxifen as the sole therapy (P=0.001). In conclusion, these data indicated that membrane‑bound VEGFR1 is frequently expressed in normal and cancerous breast epithelium. In addition, reduced or lost VEGFR1 expression may serve as a marker for poor prognosis in patients with breast cancer, who might not optimally benefit from endocrine therapy.

Assessing the therapeutic efficacy of VEGFR-1-targeted polymer drug conjugates in mouse tumor models

Polymer-drug conjugates that can actively target the tumor vasculature have emerged as an attractive technology for improving the therapeutic efficacy of cytotoxic drugs. We have recently provided, for the first time, in vivo evidence showing the significant advantage of the E-selectin-targeted N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-doxorubicin conjugate, P-(Esbp)-DOX, in inhibiting primary tumor growth and preventing the formation and development of cancer metastases. Here, we describe the design of a vascular endothelial growth factor receptor (VEGFR)-1-targeted HPMA copolymer-DOX conjugate (P-(F56)-DOX) that can actively and simultaneously target different cell types in the tumor microenvironment, such as endothelial cells (ECs), bone marrow-derived cells and many human cancer cells of diverse tumor origin. The VEGFR-1-targeted copolymer was tested for its binding, internalization and in vitro cytotoxicity in ECs (bEnd.3 and cEND cells) and cancer cells (B16-F10, 3LL and HT29). The in vivo anti-cancer activity of P-(F56)-DOX was then tested in two tumor-bearing mice (TBM) models (i.e., primary Lewis lung carcinoma (3LL) tumors and B16-F10 melanoma pulmonary metastases), relative to that of the E-selectin-targeted system (P-(Esbp)-DOX) that solely targets ECs. Our results indicate that the binding and internalization profiles of the VEGFR-1-targeted copolymer were superior towards ECs as compared to cancer cells and correlated well to the level of VEGFR-1 expression in cells. Accordingly, the VEGFR-1-targeted copolymer (P-(F56)-DOX) was more toxic towards bEnd.3 cells than to cancer cells, and exhibited significantly higher cytotoxicity than did the non-targeted control copolymer. P-(F56)-DOX inhibited 3LL tumor growth and significantly prolonged the survival of mice with B16-F10 pulmonary metastases. When compared to a system that actively targets only tumor vascular ECs, P-(F56)-DOX and P-(Esbp)-DOX exhibited comparable efficacy in slowing the growth of primary 3LL tumors and prolonging the survival of these mice. Still, P-(Esbp)-DOX had more pronounced anti-tumor activity in mice bearing B16-F10 lung metastases after a single intravenous injection, at an equivalent DOX dose. Overall, our results indicate that the VEGFR-1- and E-selectin-targeted drug delivery systems evaluated here show enhanced anti-cancer activity, and prolonged the survival of mice after a single intravenous injection. This is thus the first study comparing the anti-tumor activity of VEGFR-1- and E-selectin-targeted polymer drug conjugates in the same TBM models at an equivalent drug dose.

Diagnostic and therapeutic implications of the vascular endothelial growth factor family in cancer

Cancer progression is attained by uncontrolled cell division and metastasis. Increase in tumor size triggers different vascular channel formation to address cell nutritional demands. These channels are responsible for transferring of nutrients and gaseous to the cancer cells. Cancer vascularization is regulated by numerous factors including vascular endothelial growth factors (VEGFs). These factors play an important role during embryonic development. Members included in this group are VEGFA, VEGFB, VEGFC, PIGF and VEGFD which markedly influence cellular growth and apoptosis. Being freely diffusible these proteins act in both autocrine and paracrine fashions. In this review, genetic characterization these molecules and their putative role in cancer staging has been elaborated. Prognostic significance of these molecules along with different stages of cancer has also been summarized. Brief outline of ongoing efforts to target hot spot target sites against these VEGFs and their cognate limitations for therapeutic implications are also highlighted.

Resveratrol plays dual roles in pancreatic cancer cells

PURPOSE

Although the potential anticancer effect of resveratrol (RSV) on pancreatic cancer has been reported, its mechanism was not fully understood. The role of vascular endothelial growth factor B (VEGF-B) in cancer remains controversial. Herein, we aimed to examine whether the anticancer effect of RSV was related to the VEGF-B.

METHODS

The effect of RSV on pancreatic cancer cell line (capan-2 cells) was evaluated by CCK-8 assay, Hoechst 33342 staining, and flow cytometry. The mRNA level of VEGF-B was measured by real-time PCR. VEGF-B expression was knockdown by small interfering RNA (siRNA).The protein levels of VEGF-B, glycogen synthase kinase-3 beta (GSK-3β), and Bax were measured by Western blot.

RESULTS

Resveratrol treatment inhibited tumor growth, induced apoptosis, and up-regulated Bax expression in capan-2 cells. The mRNA and protein levels of VEGF-B were up-regulated after RSV treatment. However, VEGF-B siRNA treatment increased the apoptotic rate, and inhibited tumor activator GSK-3β, while Bax expression was not affected. The combination of RSV and VEGF-B siRNA showed significantly higher apoptotic rate in comparison with RSV or VEGF-B siRNA mono-treatment group.

CONCLUSIONS

Resveratrol plays dual roles in pancreatic cancer: as a tumor suppressor via the up-regulation of Bax; as a tumor activator via the up-regulation of VEGF-B; and the anticancer effect of RSV is much stronger than the cancer promotion effect. The combination of RSV with pharmacological inhibitor of VEGF-B might, therefore, be a promising modality for clinical pancreatic cancer therapy.

VEGF targets the tumour cell

The function of vascular endothelial growth factor (VEGF) in cancer is not limited to angiogenesis and vascular permeability. VEGF-mediated signalling occurs in tumour cells, and this signalling contributes to key aspects of tumorigenesis, including the function of cancer stem cells and tumour initiation. In addition to VEGF receptor tyrosine kinases, the neuropilins are crucial for mediating the effects of VEGF on tumour cells, primarily because of their ability to regulate the function and the trafficking of growth factor receptors and integrins. This has important implications for our understanding of tumour biology and for the development of more effective therapeutic approaches.

A gene signature combining the tissue expression of three angiogenic factors is a prognostic marker in early-stage non-small cell lung cancer

BACKGROUND

Angiogenesis and lymphangiogenesis are key mechanisms for tumor growth and dissemination. They are mainly regulated by the vascular endothelial growth factor (VEGF) family of ligands and receptors. The aim of this study was to analyze relative expression levels of angiogenic markers in resectable non-small cell lung cancer patients in order to asses a prognostic signature that could improve characterization of patients with worse clinical outcomes.

METHODS

RNA was obtained from tumor and normal lung specimens from 175 patients. Quantitative polymerase chain reaction was performed to analyze the relative expression of HIF1A, PlGF, VEGFA, VEGFA165b, VEGFB, VEGFC, VEGFD, VEGFR1, VEGFR2, VEGFR3, NRP1 and NRP2.

RESULTS

Univariate analysis showed that tumor size and ECOG-PS are prognostic factors for time to progression (TTP) and overall survival (OS). This analysis in the case of angiogenic factors also revealed that PlGF, VEGFA, VEGFB and VEGFD distinguish patients with different outcomes. Taking into account the complex interplay between the different ligands of the VEGF family and to more precisely predict the outcome of the patients, we considered a new analysis combining several VEGF ligands. In order to find independent prognostic variables, we performed a multivariate Cox analysis, which showed that the subgroup of patients with higher relative expression of VEGFA plus lower VEGFB and VEGFD presented the poorest outcome for both TTP and OS.

CONCLUSIONS

The relative expression of these three genes can be considered as an angiogenic gene signature whose applicability for the selection of candidates for targeted therapies needs to be further validated.

Vascular endothelial growth factor receptor-1 activation promotes migration and invasion of breast cancer cells through epithelial-mesenchymal transition

Vascular endothelial growth factor receptor-1 (VEGFR-1 or Flt-1), a tyrosine kinase receptor, is highly expressed in breast cancer tissues, but near absent in normal breast tissue. While VEGFR-1 expression is associated with poor prognosis of women with breast cancer, it is not clear whether it is involved in the aggressiveness of breast cancer. Thus, the present study examined whether VEGFR-1 activation is associated with the invasiveness of breast cancer. We reported that VEGFR-1 was detected in 60.6% of invasive breast carcinoma tissue sections. In addition, VEGFR-1 expression positively correlated with lymph node-positive tumor status, low expression level of membranous E-cadherin, and high expression levels of N-cadherin and Snail. We found that PlGF-mediated VEGFR-1 activation promoted migration and invasion in MCF-7 (luminal) cells and led to morphologic and molecular changes of epithelial-mesenchymal transition (EMT). This was blocked by the down-regulation of VEGFR-1. Conversely, down-regulation of VEGFR-1 in MDA-MB-231 (post-EMT) cells resulted in morphologic and molecular changes similar to mesenchymal-epithelial transition (MET), and exogenous PlGF could not reverse these changes. Moreover, VEGFR-1 activation led to an increase in nuclear translocation of Snail. Finally, MDA-MB-231 cells expressing shRNA against VEGFR-1 significantly decreased the tumor growth and metastasis capacity in a xenograft model. Histological examination of VEGFR-1/shRNA-expressing tumor xenografts showed up-regulation of E-cadherin and down-regulation of N-cadherin and Snail. These findings suggest that VEGFR-1 may promote breast cancer progression and metastasis, and therapies that target VEGFR-1 may be beneficial in the treatment of breast cancer patients.

The soluble VEGF receptor 1 and 2 expression in cerebral spinal fluid as an indicator for leukemia central nervous system metastasis

Over-expression of vascular endothelial growth factor A (VEGF-A) is correlated with leukemia metastasis. VEGF-A acts by binding to its membrane receptors R1 and R2 present in soluble forms (sVEGFR1, sVEGFR2) with different functions. sVEGFR could inhibit VEGF-A bioactivities, associated with favorable prognosis in solid tumors. However, its role is obscure in central nervous system leukemia (CNSL). The aim of this study was to investigate sVEGFR1, R2 as biomarkers in CNSL. Paired cerebrospinal fluid (CSF) and serum samples were collected from 35 leukemia cases with or without CNS metastasis. Levels of sVEGFR1 and sVEGFR2 in both CSF (sVEGFR1CSF, sVEGFR2CSF) and serum (sVEGFR1Serum, sVEGFR2Serum) were detected by ELISA. Other risk factors related to CNSL prognosis were also analyzed. sVEGFRSerum levels were 2.54-fold (sVEGFR1) and 25.6-fold (sVEGFR2) higher than sVEGFRCSF in both leukemic groups. sVEGFR1CSF in CNSL were 33 % higher than in the non-CNSL, and the levels of sVEGFR2CSF and sVEGFR2Serum had the same trend. Elevated sVEGFR1CSF and sVEGFR2CSF is closely correlated with blood-brain barrier (BBB) values and WBCCSF that is an indicator of CNSL disease burden. Cox regression analysis showed that the sVEGFR2CSF had a positive effect on event-free survival. Our data suggest that sVEGFR2CSF may be more potent than sVEGFR1CSF in predicting the outcome of leukemia patients, the balance between sVEGFR2CSF and VEGF-ACSF levels might be crucial for the progression of CNSL.

Identification of prognostic factors in canine mammary malignant tumours: a multivariable survival study

BACKGROUND

Although several histopathological and clinical features of canine mammary gland tumours have been widely studied from a prognostic standpoint, considerable variations in tumour individual biologic behaviour difficult the definition of accurate prognostic factors. It has been suggested that the malignant behaviour of tumours is the end result of several alterations in cellular physiology that culminate in tumour growth and spread. Accordingly, the aim of this study was to determine, using a multivariable model, the independent prognostic value of several immunohistochemically detected tumour-associated molecules, such as MMP-9 and uPA in stromal cells and Ki-67, TIMP-2 and VEGF in cancer cells.

RESULTS

Eighty-five female dogs affected by spontaneous malignant mammary neoplasias were followed up for a 2-year post-operative period. In univariate analysis, tumour characteristics such as size, mode of growth, regional lymph node metastases, tumour cell MIB-1 LI and MMP-9 and uPA expressions in tumour-adjacent fibroblasts, were associated with both survival and disease-free intervals. Histological type and grade were related with overall survival while VEGF and TIMP-2 were not significantly associated with none of the outcome parameters. In multivariable analysis, only a MIB-1 labelling index higher than 40% and a stromal expression of MMP-9 higher than 50% retained significant relationships with poor overall and disease-free survival.

CONCLUSIONS

The results of this study indicate that MMP-9 and Ki-67 are independent prognostic markers of canine malignant mammary tumours. Furthermore, the high stromal expressions of uPA and MMP-9 in aggressive tumours suggest that these molecules are potential therapeutic targets in the post-operative treatment of canine mammary cancer.

The prognostic and predictive value of mRNA expression of vascular endothelial growth factor family members in breast cancer: a study in primary tumors of high-risk early breast cancer patients participating in a randomized Hellenic Cooperative Oncology Group trial

INTRODUCTION

The main prognostic variables in early breast cancer are tumor size, histological grade, estrogen receptor/progesterone receptor (ER/PgR) status, number of positive nodes and human epidermal growth factor receptor 2 (HER2) status. The present study evaluated the prognostic and/or predictive value of vascular endothelial growth factor (VEGF) family members in high-risk early breast cancer patients treated with adjuvant chemo-hormonotherapy.

METHODS

RNA was isolated from 308 formalin-fixed paraffin-embedded primary tumor samples from breast cancer patients enrolled in the HE10/97 trial, evaluating adjuvant dose-dense sequential chemotherapy with epirubicin followed by cyclophosphamide, methotrexate, fluorouracil (CMF) with or without paclitaxel (E-T-CMF versus E-CMF). A fully automated method based on magnetic beads was applied for RNA extraction, followed by one-step quantitative RT-PCR for mRNA analysis of VEGF-A, -B, -C and vascular endothelial growth factor receptor (VEGFR) 1, 2, 3.

RESULTS

With a median follow-up of 8 years, 109 patients (35%) developed a relapse and 80 patients (26%) died. In high VEGF-C and VEGFR1 mRNA expressing tumors, ER/PgR-negative tumors (Fisher's exact test, P = 0.001 and P = 0.021, respectively) and HER2-positive tumors (P <0.001 and P = 0.028, respectively) were more frequent than in low VEGF-C and VEGFR1 expressing tumors, respectively. From the VEGF family members evaluated, high VEGFR1 mRNA expression (above the 75th percentile) emerged as a significant negative prognostic factor for overall survival (OS; hazard ratio (HR) = 1.60, 95% confidence interval (CI): 1.01 to 2.55, Wald's P = 0.047) and disease-free survival (DFS; HR = 1.67, 95% CI: 1.13 to 2.48, P = 0.010), when adjusting for treatment group. High VEGF-C mRNA expression was predictive for benefit from adjuvant treatment with paclitaxel (E-T-CMF arm) for OS (test for interaction, Wald's P = 0.038), while in multivariate analysis the interaction of VEGF-C with taxane treatment was significant for both OS (Wald's P = 0.019) and DFS (P = 0.041) and continuous VEGF-B mRNA expression values for OS (P = 0.019).

CONCLUSIONS

The present study reports, for the first time, that VEGF-C mRNA overexpression, as assessed by qRT-PCR, has a strong predictive value in high-risk early breast cancer patients undergoing adjuvant paclitaxel-containing treatment. Further studies are warranted to validate the prognostic and/or predictive value of VEGF-B, VEGF-C and VEGFR1 in patients treated with adjuvant therapies and to reveal which members of the VEGF family could possibly be useful markers in identifying patients who will benefit most from anti-VEGF strategies.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12611000506998.

Role of the VEGF/VEGFR axis in cancer biology and therapy

New vessel formation (angiogenesis) is an essential physiological process for embryologic development, normal growth, and tissue repair. Angiogenesis is tightly regulated at the molecular level; however, this process is dysregulated in several pathological conditions such as cancer. The imbalance between pro- and antiangiogenic signaling molecules within tumors creates an abnormal vascular network that is characterized by dilated, tortuous, and leaky vessels. The pathophysiological consequences of these vascular abnormalities include temporal and spatial heterogeneity in tumor blood flow, oxygenation, and increased tumor interstitial fluid pressure. The resultant microenvironment deeply impacts on tumor progression, and also leads to a reduction in therapy efficacy. The discovery of vascular endothelial growth factor (VEGF) as a major driver of tumor angiogenesis has led to efforts to develop novel therapeutics aimed at inhibiting its activity. Anti-VEGF therapy has become an important option for the management of several human malignancies; however, a significant number of patients do not respond to anti-VEGF therapy when used either as single agent or in combination with chemotherapy. In addition, the benefit of antiangiogenic therapy is relatively short lived and the majority of patients relapse and progress. An increasing amount of reports suggest several potential mechanisms of resistance to antiangiogenic therapy including, but not limited to, tumor hypoxia. This chapter discusses the role of the VEGF axis in tumor biology and highlights the clinical application of anti-VEGF therapies elaborating on pitfalls and strategies to improve clinical outcome.

Expression of vascular endothelial growth factor and vascular endothelial growth factor receptors 1 and 2 in invasive breast carcinoma: prognostic significance and relationship with markers for aggressiveness

AIMS

Vascular endothelial growth factor (VEGF), VEGF receptor 1 (VEGFR-1) and VEGF receptor 2 (VEGFR-2) play a role in breast cancer growth and angiogenesis. We examined the expression and relationship with clinical outcome and other prognostic factors.

METHODS AND RESULTS

Tumour sections from 468 breast cancer patients were immunostained for VEGF, VEGFR-1, and VEGFR-2, and their relationships with tumour vascularity, disseminated tumour cells (DTCs) in bone marrow and other clinicopathological parameters were evaluated. VEGF, VEGFR-1 and VEGFR-2 immunoreactivities were observed in invasive breast carcinoma cells. VEGF expression was significantly associated with VEGFR-1 and VEGFR-2 expression (P < 0.001). High-level cytoplasmic expression of VEGFR-1 was associated with significantly reduced distant disease-free survival (DDFS) (P = 0.017, log-rank) and breast cancer-specific survival (BCSS) (P = 0.005, log-rank) for all patients, and for node-negative patients without systemic treatment (DDFS, P = 0.03, log-rank; BCSS, P = 0.009, log-rank). VEGFR-1 expression was significantly associated with histopathological markers of aggressiveness (P < 0.05). Significantly reduced survival was observed in DTC-positive patients as compared with DTC-negative patients in the combined moderate/high VEGFR-1 group (P < 0.001 for DDFS and BCSS), and the same was true for DDFS in the moderate VEGFR-2 group (P = 0.006).

CONCLUSIONS

High-level expression of VEGFR-1 indicates reduced survival. Higher-level expression of VEGFR-1 or VEGFR-2 in primary breast carcinomas combined with the presence of DTC selects a prognostically unfavourable patient group.

Decoy-DNA against special AT-rich sequence binding protein 1 inhibits the growth and invasive ability of human breast cancer

"Triple-negative" (TN) breast cancers, which are characterized by estrogen receptor (-), progesterone receptor (-), and human epidermal growth factor receptor 2 (-), are typically associated with poor prognosis because of their aggressive tumor phenotypes. In recent years, the number of patients with breast cancers has remarkably increased, but there are only few available drugs for treatment of TN breast cancers. The development of novel drugs targeting TN breast cancer is urgently required. In the present study, we focused on the function of special AT-rich sequence binding protein 1 (SATB1) as a target molecule for the treatment of TN breast cancers. By recruiting chromatin remodeling enzymes and transcriptional factors, SATB1 regulates the expression of >1,000 genes related to cell growth and translocation. We synthesized a decoy DNA against SATB1, including the recognition sequence of SATB1. We examined the inhibitory effects of the decoy DNAs on cellular proliferation of a TN metastatic breast cancer cell line (MDA-MB-231). SATB1-decoy DNA inhibited the proliferation of MDA-MB-231 cells. Especially, it was significant that SATB1-decoy DNA drastically reduced the invasive and metastatic capacity of MBA-MB-231 cells. Further, in the case of MCF7 cells (SATB1-negative breast cancer cell line), SATB1-decoy DNA did not exhibit any inhibitory effect. These data suggest that SATB1-decoy DNA may be an effective candidate for use as a molecular-targeting drug for treatment of TN breast cancer.

Breast Tumor Angiogenesis and Tumor-Associated Macrophages: Histopathologist's Perspective

Much progress has been made since the conceptualization of tumor angiogenesis—the induction of growth of new blood vessels by tumor—as a salient feature of clinically significant primary or metastatic cancers. From a practicing histopathologist's point of view, we appraise the application of this concept in breast cancer with particular reference to the evaluation of proangiogenic factors and the assessment of new microvessels in histopathological examination. Recently, much focus has also been centered on the active roles played by tumor-associated macrophages in relation to tumor angiogenesis. We review the literature; many data supporting this facet of tumor angiogenesis were derived from the breast cancer models. We scrutinize the large body of clinical evidence exploring the link between the tumor-associated macrophages and breast tumor angiogenesis and discuss particularly the methodology and limitations of incorporating such an assessment in histopathological examination.

Immunohistochemical study of the angiogenetic network of VEGF, HIF1α, VEGFR-2 and endothelial nitric oxide synthase (eNOS) in human breast cancer

BACKGROUND

The role of Nitric Oxide (NO) in angiogenesis has not been fully clarified yet. A dual role for NO, either inductive or inhibitory, has been proposed on the basis of different effects that high or low concentrations of NO may exert on the angiogenic process. Additionally, it has been referred that NO may induce VEGF production, while VEGF may induce NO production via up-regulation of the endothelial nitric oxide synthase (eNOS), the two pathways being reverse. The aim of the current study was to investigate the expression of key molecules involved in these opposite pathways in primary breast cancer.

METHODS

Representative tumor samples from 242 patients with early-stage breast cancer (invasive ductal breast carcinomas) were investigated for the expression of VEGF, VEGFR-2, HIF1α, iNOS, and eNOS using immunohistochemistry.

RESULTS

Endothelial NOS was found in 159 cases, VEGF in 131 cases, HIF-1α in 139 cases, VEGFR2 in 185 cases and inducible NOS (iNOS) in 22 cases. There was a significant correlation between the expression of VEGF and VEGFR-2, eNOS and VEGF, eNOS and VEGFR-2, eNOS and HIF1α. No statistically significant correlation was found between iNOS and the rest of the studied molecules.

CONCLUSIONS

In breast cancer cases, the major molecules regulating NO and VEGF production can be co-expressed in the individual carcinomas implying a possibility for the relevant pathways to be active; however appropriate functional experiments remain to be conducted to prove such a hypothesis.

Estimation of immunohistochemical expression of VEGF in ductal carcinomas of the breast

Vascular endothelial growth factor A (VEGF-A) is a very important growth factor in angiogenesis and holds potential as both a predictive marker for anti-angiogenic cancer treatment and a prognostic variable. Consequently, reliable estimation of VEGF expression is crucial. Investigators immunostained whole tumor sections for VEGF-A, VEGF-B, and VEGFR-1 of invasive ductal carcinomas of the breast and scored the tumors manually with staining intensity as the only parameter and by a combination of qualitative and quantitative information. The investigators also introduce an automated method for analyzing VEGF expression (so-called AI score) using the same tumor sections. Analysis of 100% of the tumor area was performed and the results were compared with the reduced analysis of 25% of the tumor area. These analyses were performed at ×5 and ×10 magnification, and each analysis was repeated in a second run with a new delineation of the tumor area. The AI scores were correlated to the manual scoring of VEGF intensity, but reproducibility of manual IHC scores was rather poor. The AI scores were reproducible, and the restricted analysis of 25% of the tumor area at ×5 magnifications was the most efficient considering time consumption and data load.

Vascular endothelial growth factors and receptors: anti-angiogenic therapy in the treatment of cancer

Vascular endothelial growth factors (VEGFs) are critical regulators of vascular and lymphatic function during development, in health and in disease. There are five mammalian VEGF ligands and three VEGF receptor tyrosine kinases. In addition, several VEGF co-receptors that lack intrinsic catalytic activity, but that indirectly modulate the responsiveness to VEGF contribute to the final biological effect. This review describes the molecular features of VEGFs, VEGFRs and co-receptors with focus on their role in the treatment of cancer.

The controversial role of placental growth factor in tumor growth

The significance of placental growth factor (PlGF) in tumor growth is still a matter of debate. Depending on the model, PlGF overexpression has been shown to result in tumor growth promotion or inhibition. This review article summarizes the most relevant literature data concerning this still unsolved important question.

Significance of expression of vascular endothelial growth factor B and its splice isoforms in different types of liver lesions

AIM: To detect the mRNA expression of vascular endothelial cell growth factor B (VEGF-B) and its splice isoforms VEGF-B167 and VEGF-B186 in different types of liver lesions and to assess their clinical significance.

METHODS: The mRNA expression of VEGF-B, VEGF-B167 and VEGF-B186 in liver cancer, cancer-adjacent tissue, liver cirrhosis, chronic hepatitis B, and normal liver tissue was detected by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). The correlation of VEGF-B, VEGF-B167, and VEGF-B186 expression with the clinical pathological data of patients was analyzed, and survival analysis was performed using follow-up data.

RESULTS: There were no statistical differences in the expression levels of total VEGF-B and VEGF-B186 among each group, while the expression level of VEGF-B167 mRNA was significantly different among each group, highest in the normal group but lowest in liver cirrhosis group (252.59 vs 168.00, P = 0.005). The expression level of VEGF-B167 mRNA was significantly higher in the liver cancer group than in the chronic hepatitis B group (234.13 vs 170.72, 168.00, both P < 0.05). The overall survival rate and tumor-free survival rate of patients with low VEGF-B167 expression tended to be higher than those of patients with high VEGF-B167 expression (P = 0.097, 0.023). The expression levels of total VEGF-B, VEGF-B167 and VEGF-B186 had no significant correlation with sex, age, virus infection, liver cirrhosis, Child-Pugh score, AFP score, tumor number or size, vascular invasion, TNM stage, or tumor differentiation.

CONCLUSION: VEGF-B is involved in hepatocarcinogenesis and VEGF-B167 plays a more important role than VEGF-B186 in this process. Patients with low VEGF-B167 expression have good prognosis since their postoperative overall survival rate and tumor-free survival rate are higher than those with high VEGF-B167 expression.

Suppressive effects of vascular endothelial growth factor-B on tumor growth in a mouse model of pancreatic neuroendocrine tumorigenesis

Background

The family of vascular endothelial growth factors (VEGF) contains key regulators of blood and lymph vessel development, including VEGF-A, -B, -C, -D, and placental growth factor. The role of VEGF-B during physiological or pathological angiogenesis has not yet been conclusively delineated. Herein, we investigate the function of VEGF-B by the generation of mouse models of cancer with transgenic expression of VEGF-B or homozygous deletion of Vegfb.

Methodology/Principal Findings

Ectopic expression of VEGF-B in the insulin-producing β-cells of the pancreas did not alter the abundance or architecture of the islets of Langerhans. The vasculature from transgenic mice exhibited a dilated morphology, but was of similar density as that of wildtype mice. Unexpectedly, we found that transgenic expression of VEGF-B in the RIP1-Tag2 mouse model of pancreatic neuroendocrine tumorigenesis retarded tumor growth. Conversely, RIP1-Tag2 mice deficient for Vegfb presented with larger tumors. No differences in vascular density, perfusion or immune cell infiltration upon altered Vegfb gene dosage were noted. However, VEGF-B acted to increase blood vessel diameter both in normal pancreatic islets and in RIP1-Tag2 tumors.

Conclusions/Significance

Taken together, our results illustrate the differences in biological function between members of the VEGF family, and highlight the necessity of in-depth functional studies of VEGF-B to fully understand the effects of VEGFR-1 inhibitors currently used in the clinic.

Evaluation of vascular endothelial growth factor as a prognostic marker for local relapse in early-stage breast cancer patients treated with breast-conserving therapy

PURPOSE

Vascular endothelial growth factor (VEGF) is an important protein involved in the process of angiogenesis that has been found to correlate with relapse-free and overall survival in breast cancer, predominantly in locally advanced and metastatic disease. A paucity of data is available on the prognostic implications of VEGF in early-stage breast cancer; specifically, its prognostic value for local relapse after breast-conserving therapy (BCT) is largely unknown. The purpose of our study was to assess VEGF expression in a cohort of early-stage breast cancer patients treated with BCT and to correlate the clinical and pathologic features and outcomes with overexpression of VEGF.

METHODS AND MATERIALS

After obtaining institutional review board approval, the paraffin specimens of 368 patients with early-stage breast cancer treated with BCT between 1975 and 2005 were constructed into tissue microarrays with twofold redundancy. The tissue microarrays were stained for VEGF and read by a trained pathologist, who was unaware of the clinical details, as positive or negative according the standard guidelines. The clinical and pathologic data, long-term outcomes, and results of VEGF staining were analyzed.

RESULTS

The median follow-up for the entire cohort was 6.5 years. VEGF expression was positive in 56 (15%) of the 368 patients. Although VEGF expression did not correlate with age at diagnosis, tumor size, nodal status, histologic type, family history, estrogen receptor/progesterone receptor status, or HER-2 status, a trend was seen toward increased VEGF expression in the black cohort (26% black vs. 13% white, p=.068). Within the margin-negative cohort, VEGF did not predict for local relapse-free survival (RFS) (96% vs. 95%), nodal RFS (100% vs. 100%), distant metastasis-free survival (91% vs. 92%), overall survival (92% vs. 97%), respectively (all p>.05). Subset analysis revealed that VEGF was highly predictive of local RFS in node-positive, margin-negative patients (86% vs. 100%, p=.029) on univariate analysis, but it did not retain its significance on multivariate analysis (hazard ratio, 2.52; 95% confidence interval, 0.804-7.920, p=.113). No other subgroups were identified in which a correlation was found between VEGF expression and local relapse.

CONCLUSION

To our knowledge, our study is the first to assess the prognostic value of VEGF with the endpoint of local relapse in early-stage breast cancer treated with BCT, an important question given the recent increased use of targeted antiangiogenic agents in early-stage breast cancer. Our study results suggest that VEGF is not an independent predictor of local RFS after BCT, but additional, larger studies specifically analyzing the endpoint of VEGF and local relapse are warranted.

Trastuzumab-based neoadjuvant therapy in patients with HER2-positive breast cancer

Overexpression, or gene amplification, of the human epidermal growth factor receptor 2 (HER2) is evident in 20% to 25% of breast cancers. The biologic agent trastuzumab is an HER2-targeted monoclonal antibody that inhibits the proliferation of tumor cells and induces tumor cell death through multiple mechanisms of action. Currently, trastuzumab is approved for use in the adjuvant and metastatic settings. Trials combining trastuzumab with neoadjuvant chemotherapy suggest that patients with HER2-positive breast cancer also may benefit from preoperative trastuzumab. For this article, the author reviewed efficacy and safety data from key studies of patients who received neoadjuvant trastuzumab-based therapy. Studies were identified from literature searches of publication and congress databases. The results of 3 large phase 3 trials (the M. D. Anderson Cancer Center neoadjuvant trastuzumab trial, the Neoadjuvant Herceptin [NOAH] trial, and the German Breast Group/Gynecologic Oncology Study Group "GeparQuattro" trial) demonstrated that, compared with chemotherapy alone, neoadjuvant trastuzumab plus chemotherapy significantly increased pathologic complete response rates to as high as 65%. Improvements in disease-free, overall, and event-free survival also were reported in the NOAH trial. In addition to demonstrated efficacy, a low incidence of cardiac dysfunction suggests that neoadjuvant trastuzumab is both effective and well tolerated. Similar results have been reported in a range of phase 2 studies using different trastuzumab-based regimens. These encouraging data led the National Comprehensive Cancer Network to recommend treating patients who have operable, locally advanced, HER2-positive breast cancer with neoadjuvant paclitaxel plus trastuzumab followed by 5-fluorouracil, epirubicin, and cyclophosphamide plus trastuzumab.

Immunohistochemical expression of vascular endothelial growth factor in canine mammary tumours

The histopathological and clinical aspects of canine mammary tumours (CMTs) have been widely studied, but the variation in the biological behaviour of these neoplasms hampers the identification of prognostic factors. Sustained angiogenesis has been suggested to be one of the most important factors underlying tumour growth and invasion. This process involves the action of several growth factors including vascular endothelial growth factor (VEGF). The present study characterizes the relationship between immunohistochemical expression of VEGF and gross (e.g. size and tissue fixation) and microscopical (e.g. type, growth, necrosis, lymphoid infiltration, lymph node metastasis, histological grade and proliferation index) features of CMTs. Forty-eight benign and 64 malignant CMTs were evaluated. Statistical analysis failed to show a significant relationship between VEGF expression and the pathological features, suggesting that VEGF expression occurs in both benign and malignant tumours and is independent of histological type, proliferation, tissue invasion or local metastatic capacity.

Vascular endothelial growth factor receptor-1 in human cancer: concise review and rationale for development of IMC-18F1 (Human antibody targeting vascular endothelial growth factor receptor-1)

The human vascular endothelial growth factor receptor-1 (VEGFR-1, or Flt-1) is widely expressed in normal and pathologic tissue and contributes to the pathogenesis of both neoplastic and inflammatory diseases. In human cancer, VEGFR-1 mediated signaling is responsible for both direct tumor activation and angiogenesis. VEGFR-1 mediated activation of nonmalignant supporting cells, particularly stromal, dendritic, hematopoietic cells, and macrophages, is also likely important for cancer pathogenesis. VEGFR-1 is also hypothesized to enable the development of cancer metastases by means of activation and premetastatic localization in distant organs of bone marrow-derived hematopoietic progenitor cells, which express VEGFR-1. IMC-18F1 is a fully human IgG(1) antibody that binds to VEGFR-1 and has been associated with the inhibition of cancer growth in multiple in vitro and human tumor xenograft models. The preliminary results of phase 1 investigations have also indicated a favorable safety profile for IMC-18F1 at doses that confer antibody concentrations that are associated with relevant antitumor activity in preclinical models.

Immunostaining with D2-40 improves evaluation of lymphovascular invasion, but may not predict sentinel lymph node status in early breast cancer

Background

Sentinel lymph node (SLN) biopsy is a widely used diagnostic procedure in the management of early breast cancer. When SLN is free of metastasis, complete axillary dissection may be skipped for staging in clinically N0 patients, allowing a more conservative procedure. Histological tumor features that could reliably predict SLN status have not yet been established. Since the degree of tumor lymphangiogenesis and vascularization may theoretically be related to the risk of lymph node metastasis, we sought to evaluate the relationship between lymph vessel invasion (LVI), lymphatic microvascular density (LVD), microvascular density (MVD) and VEGF-A expression, with SLN status and other known adverse clinical risk factors.

Methods

Protein expression of D2–40, CD34, and VEGF-A was assessed by immunohistochemistry on paraffin-embedded sections of primary breast cancer specimens from 92 patients submitted to SLN investigation. The presence of LVI, the highest number of micro vessels stained for D2–40 and CD34, and the protein expression of VEGF-A were compared to SLN status, clinicopathological features and risk groups.

Results

LVI was detected in higher ratios by immunostaining with D2–40 (p < 0.0001), what would have changed the risk category from low to intermediate in four cases (4.3%). There was no association between LVI and other angiogenic parameters determined by immunohistochemistry with SLN macrometastases, clinical features or risk categories.

Conclusion

Assessment of LVI in breast carcinoma may be significantly increased by immunostaining with D2–40, but the clinical relevance of altering the risk category using this parameter may not be advocated according to our results, neither can the use of LVI and LVD as predictors of SLN macrometastasis in early breast cancer.

FLT1 and its ligands VEGFB and PlGF: drug targets for anti-angiogenic therapy?

Less than 5 years ago, it was still not clear whether anti-angiogenic drugs would prove successful in the clinic. After numerous patients with cancer or age-related macular degeneration have been treated with these drugs, they have now become part of the standard range of therapeutic tools. Despite this milestone, anti-angiogenic therapy still faces a number of clinical hurdles, such as improving efficacy, avoiding escape and resistance, and minimizing toxicity. Hopefully, other agents with complementary mechanisms, such as those that target placental growth factor, will offer novel opportunities for improved treatment.

Comparison of serum VEGF and its soluble receptor sVEGFR1 with serum cell-free DNA in patients with breast tumor

BACKGROUND

The observed elevated levels of vascular endothelial growth factor (VEGF), its soluble receptor (sVEGFR1) and cell-free DNA (cfDNA) in the serum of patients with various cancers have attracted much attention to the possibility of using these agents as biomarkers for cancers. We wanted to find out whether VEGF, VEGFR1 or cfDNA is a biomarker for breast cancer.

METHODS

In this study, we used enzyme-linked immunosorbent assay (ELISA) to examine the levels of serum VEGF and VEGFR1 in 23 patients with benign tumors, 19 patients with breast cancer and 32 age-matched healthy females. The levels of circulating cell-free DNA were measured using TaqMan real-time PCR analysis for the glyceraldehydes 3 phosphate dehydrogenase gene (GAPDH), We compared the serum levels of VEGF and its soluble receptors with those of the cell-free serum DNA.

RESULTS

In terms of serum levels of either VEGF or its soluble receptors VEGFR1, we found no significant difference between healthy individuals and women with benign breast tumors and breast cancer. However, there was a significant increase in circulating cell-free DNA in women with both benign and malignant breast tumors when compared with the corresponding healthy control group. We also found a significant negative correlation between VEGF and its soluble receptor VEGFR1 (r=-0.328 and p=0.004), and a significant positive correlation between VEGF and cell-free serum DNA (r=0.241 and p=0.033).

CONCLUSIONS

We can conclude that quantitative analysis of circulating cell-free DNA in serum may provide molecular biological understanding of breast tumors in women. It would also suggest that serum levels of VEGF and VEGFR1 have less significance.

Expression of the epidermal growth factor receptor (EGFR) and the phosphorylated EGFR in invasive breast carcinomas

Introduction

Epidermal growth factor receptor (EGFR) is involved in regulating cell growth in breast carcinomas. Its activated form, phosphorylated EGFR (pEGFR), is correlated with poor prognosis in lung cancer, but it has not yet been fully investigated in breast cancer. The aim of this study was to investigate the expressions of EGFR and pEGFR and their correlation with overall and disease-free survival, clinicopathological parameters and biological markers of invasion and angiogenesis (phosphorylated Akt [pAkt], urokinase plasminogen activator receptor [uPAR], matrix metalloproteinase [MMP]-14, vascular endothelial growth factor receptor [VEGFR]-1/Flt-1).

Methods

A three-step immunohistochemical method was applied to paraffin-embedded sections from 154 patients with invasive breast carcinoma in order to detect expressions of the proteins EGFR, pEGFR, oestrogen receptor, progesterone receptor, c-erbB-2, pAkt, VEGFR-1/Flt-1, MMP-14 and uPAR. The results were evaluated statistically using the χ² test. Overall and disease-free survival distribution curves were assessed using the Kaplan-Meier test and log-rank statistics, followed by Cox proportional hazards regression model.

Results

EGFR and pEGFR proteins were immunodetected in the membrane of the malignant cells (11.3% and 35.7%, respectively). EGFR expression was positively correlated with nuclear grade (P = 0.001) and negatively correlated with the hormonal receptor oestrogen receptor (P = 0.005). pEGFR was positively related to the Akt pathway (P = 0.008) and appeared to participate in invasion and metastasis (uPAR, P = 0.049; MMP-14, P = 0.025; VEGFR-1/Flt-1, P = 0.016). Univariate analysis showed that the EGFR/pEGFR phenotype was associated with poor overall survival (P = 0.019), a finding further supported by multivariate analysis (P = 0.013).

Conclusion

These data provide evidence that pEGFR expression is related to angiogenesis (via VEGFR-1/Flt-1, MMP-14 and pAkt pathways) and invasiveness (via uPAR, MMP-14 and pAkt pathways) and that the EGFR/pEGFR phenotype is associated with poor patient survival in invasive breast cancer.

Breast tumour angiogenesis

The central importance of tumour neovascularization has been emphasized by clinical trials using antiangiogenic therapy in breast cancer. This review gives a background to breast tumour neovascularization in in situ and invasive breast cancer, outlines the mechanisms by which this is achieved and discusses the influence of the microenvironment, focusing on hypoxia. The regulation of angiogenesis and the antivascular agents that are used in an antiangiogenic dosing schedule, both novel and conventional, are also summarized.