Breast cancer: the role of angiogenesis and antiangiogenic therapy

Dietary protein sources and tumoral overexpression of RhoA, VEGF-A and VEGFR2 genes among breast cancer patients

BACKGROUND

High protein intake may promote angiogenesis giving support to the development of metastasis according to the experimental data. However, nutritional epidemiologic evidence is inconsistent with metastasis. Therefore, we aimed to study the association between dietary intake of protein and tumoral expression levels of Ras homologous gene family member A (RhoA), vascular endothelial growth factor-A (VEGF-A), and VEGF receptor-2 (VEGFR2) in primary breast cancer (BC) patients.

METHODS

Over this consecutive case series, 177 women primary diagnosed with histopathologically confirmed BC in Tabriz (Iran) were enrolled between May 2011 and November 2016. A validated food frequency questionnaire was completed for eligible participants. Fold change in gene expression was measured using quantitative real-time PCR. Principal component factor analysis (PCA) was used to express dietary groups of proteins.

RESULTS

Total protein intake was associated with the expression level of VEGF-A in progesterone receptor-positive (PR+: β = 0.296, p < 0.01) and VEGFR2 in patients with involvement of axillary lymph node metastasis (ALNM+: β = 0.295, p < 0.01) when covariates were adjusted. High animal protein intake was correlated with overexpression of RhoA in tumors with estrogen receptor-positive (ER+: β = 0.230, p < 0.05), ALNM+ (β = 0.238, p < 0.05), and vascular invasion (VI+: β = 0.313, p < 0.01). Animal protein intake was correlated with the overexpression of VEGFR2 when tumors were positive for hormonal receptors (ER+: β = 0.299, p < 0.01; PR+: β = 0.296, p < 0.01). Based on the PCA outputs, protein provided by whole meat (white and red meat) was associated inversely with RhoA expression in ALNM+ (β = - 0.253, p < 0.05) and premenopausal women (β = - 0.285, p < 0.01) in adjusted models. Whole meat was correlated with VEGFR2 overexpression in VI+ (β = 0.288, p < 0.05) and premenopausal status (β = 0.300, p < 0.05) in adjusted models. A group composed of dairy products and legumes was correlated with the overexpression of RhoA (β = 0.249, p < 0.05) and VEGF-A (β = 0.297, p < 0.05) in VI+.

CONCLUSIONS

Based on the multivariate findings, the dietary protein could associate with the overexpression of RhoA and VEGF-VEGFR2 in favor of lymphatic and vascular metastasis in BC patients.

A novel bisindole-PBD conjugate inhibits angiogenesis by regulating STAT3 and VEGF in breast cancer cells

AIMS

Breast cancer is highly resistant to chemotherapeutic approach and hence, alternative strategies have been developed to fight against this heterogeneous group of disease. In particular, many studies have demonstrated about various drugs for the treatment of breast cancer. In our study, we assessed the anti-angiogenenic activities of Bisindole-PBD (5b) in MCF-7 and MDA-MB-231 cell lines.

MAIN METHODS

In vitro Endothelial Cell (HUVEC) Tube Formation Assay was performed to show inhibitory role of 5b along with its role upon wound healing process in breast cancer cells in vitro. Semi-quantitative reverse transcription PCR (RT-PCR) was also done to examine the expression of VEGF in response to 5b in breast cancer cells and in HUVEC cells. siRNA transfection study explored STAT3 mediated VEGF transcription in breast cancer cells MCF-7 and MDA-MB-231. CAM assay was performed to see the role of 5b on vessel formation in chicken embryo.

KEY FINDINGS

From in vitro data we have demonstrated that 5b played a role in regulation of breast cancer cell proliferation by inhibiting angiogenesis. Test drug 5b suppressed the expression VEGF at both transcriptional and post transcriptional levels. Apart from this, there was significant down regulation in STAT3 level after drug treatment, which was found to be involved in the VEGF transcription. Metastasis related MMP-2 and MMP-9 expressions were also modulated by 5b. In vivo study by Chick Chorioallantoic Membrane (CAM) Assay also showed anti-angiogenesis role of the test drug which was consistent with the in vitro data.

SIGNIFICANCE

Altogether, our data demonstrated 5b as potent small molecule with anti-angiogenic activities.

Tanshinone IIA inhibits HIF-1α and VEGF expression in breast cancer cells via mTOR/p70S6K/RPS6/4E-BP1 signaling pathway

Hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) play important roles in angiogenesis and tumor growth. Tanshinone IIA (T2A) is a novel antiangiogenic agent with promising antitumor effects; however, the molecular mechanism underlying the antiangiogenic effects of T2A remains unclear. In the present study, we provided evidence showing that T2A inhibited angiogenesis and breast cancer growth by down-regulating VEGF expression. Specifically, T2A repressed HIF-1α expression at the translational level and inhibited the transcriptional activity of HIF-1α, which led to the down-regulation of VEGF expression. Suppression of HIF-1α synthesis by T2A correlated with strong dephosphorylation of mammalian target of rapamycin (mTOR) and its effectors ribosomal protein S6 kinase (p70S6K) and eukaryotic initiation factor 4E-binding protein-1 (4E-BP1), a pathway regulating HIF-1α expression at the translational level. In addition, we also found that T2A inhibited the angiogenesis and growth of human breast cancer xenografts in nude mice through suppression of HIF-1α and VEGF. Our study provides novel perspectives and potential targets for the treatment of human breast cancer.

Clinical experience with ramucirumab : outcomes in breast cancer

INTRODUCTION

Monoclonal antibodies and small molecules targeting the VEGF pathway are part of the arsenal to treat malignant tumors. Antiangiogenesis therapies has been studied in breast cancer with partial success, reflected by the approval of bevacizumab in Europe but not in United States, for metastatic breast cancer (mBC). Ramucirumab is a mAb against VEGFR-2 interfering with the normal activation of this receptor by its natural ligand VEGF.

AREAS COVERED

This article will review the preclinical data available to date for ramucirumab, as well as survey the main clinical trials of antiangiogenic agents reported in breast cancer, focusing on Phase III clinical trials. It will also review the clinical trial data for ramucirumab in mBC, including the design of the Phase II trials, and report on the preliminary results of the TRIO-012 trial. This trial did not meet its primary end point in progression-free survival and has to be considered as a negative trial.

EXPERT OPINION

Despite preliminary positive data with ramucirumab in other metastatic solid tumors reported to date, the results of TRIO-012 discourage pursuing more efforts with ramucirumab in mBC unless predictive and reproducible biomarkers can be established to select those patients who are most likely to benefit from it.

No association between genetic variants in angiogenesis and inflammation pathway genes and breast cancer survival among Chinese women

BACKGROUND

Angiogenesis and inflammation are implicated in breast cancer prognosis; however, the role of individual germline variation in related genes is unknown.

METHODS

A two-stage candidate pathway association study was conducted among 6983 Chinese women. Stage 1 included 2884 women followed for a median of 5.7 years; Stage 2 included 4099 women followed for a median of 4.0 years. Cox proportional hazards regression was used to estimate the effects of genetic variants on disease-free survival (DFS) and overall survival (OS).

RESULTS

Stage 1 included genotyping of 506 variants in 22 genes; analysis was conducted for 370 common variants. Nominally significant associations with DFS and/or OS were found for 20 loci in ten genes in Stage 1; variants in 19 loci were successfully genotyped and evaluated in Stage 2. In analyses of both study stages combined, nominally significant associations were found for nine variants in seven genes; none of these associations surpassed a significance threshold level corrected for the total number of variants evaluated in this study.

CONCLUSIONS

No association with survival was found for 370 common variants in 22 angiogenesis and inflammation pathway genes among Chinese women with breast cancer.

IMPACT

Our data do not support a large role for common genetic variation in 22 genes in breast cancer prognosis; research on angiogenesis and inflammation genes should focus on common variation in other genes, rare host variants, or tumor alterations.

Crosstalk between HER2 signaling and angiogenesis in breast cancer: molecular basis, clinical applications and challenges

PURPOSE OF REVIEW

Angiogenesis is an essential hallmark of cancer. Targeting angiogenesis has proven its efficacy in the modern therapeutic paradigm. HER2 positive breast cancer, in particular, is a challenging disease in which resistance to standard therapy has been attributed to parallel and downstream signaling cascades including angiogenesis. This review explores the molecular mechanisms underlying crosstalk between HER2 signaling and angiogenesis. It highlights the role of angiogenesis in the emerging resistance to anti-HER2 therapy. It surveys the current repertoire of clinical trials involving use of combination of anti-HER2 and antiangiogenic therapies. Finally, it entertains the hopes and challenges posed by this novel therapeutic approach.

RECENT FINDINGS

HER2 signaling upregulates angiogenesis at different levels and by different mechanisms. A large number of clinical trials were conducted in attempt to exploit the potential benefit of the combination. Results of early phase trials were promising. However, in the late phase clinical trials, the AVEREL trial did not demonstrate a consistent benefit for bevacizumab in the HER2 positive breast cancer patient population. The BETH trial is ongoing and recruiting patients. Safety issues regarding cardiovascular toxicity of the combination have been already raised. Negative experience of dual EGFR and VEGF targeting in colon cancer cannot be overlooked.

SUMMARY

Angiogenesis and HER2 signaling are closely related at the molecular level. Appraisal of efficacy of antiangiogenic therapies requires revisit of the current literature as well as following the results of ongoing trials.

Antiangiogenic strategies in breast cancer management

Angiogenesis is considered one of the key mechanisms of tumour growth and survival. Therefore it represents an ideal pharmaceutical target. Many antiangiogenic agents have been developed so far in several solid tumours and also in breast cancer. Vascular endothelial growth factor (VEFG) is the main target and both monoclonal antibodies and small molecules belonging to the tyrosine kinase inhibitors directed against VEGF(R) have been developed. Some other therapeutic approaches have shown to exert some antiangiogenic activity, such as hormonal agents, metronomic chemotherapy, bisphosphonates and others. In this paper we provide an introduction of the current data supporting the angiogenesis in breast cancer and a review of the most relevant antiagiogenic therapies which have been investigated so far.

High levels of vascular endothelial growth factor and its receptors (VEGFR-1, VEGFR-2, neuropilin-1) are associated with worse outcome in breast cancer

Vascular endothelial growth factor has been shown to be up-regulated in breast cancers. Vascular endothelial growth factor receptors, VEGFR-1 and VEGFR-2, are the principal mediators of its effects. Together with VEGFR-1 and VEGFR-2, neuropilin-1 may act as a coreceptor for vascular endothelial growth factor. Although vascular endothelial growth factor exerts important effects on endothelial cells, VEGFRs are likely present on tumor cells as well. We used AQUA to analyze tumor-specific expression of vascular endothelial growth factor, VEGFR-1, VEGFR-2, and neuropilin-1 on a large cohort of breast cancer tissue microarray. Two-fold redundant arrays were constructed from 642 cases of primary breast adenocarcinomas. Automated image analysis with AQUA (Automated Quantitative Analysis) was then performed to determine a quantitative expression score. Scores from redundant arrays were normalized and averaged. Kaplan-Meier survival analysis showed that high levels of vascular endothelial growth factor, VEGFR-1, VEGFR-2, and neuropilin-1 were all significantly associated with survival (Miller Siegmeund corrected P = .0020, .0160, and .0320, respectively). In addition, vascular endothelial growth factor and neuropilin-1 retained a significant association with survival independent of other standard prognostic factors. Vascular endothelial growth factor, VEGFR-1 and -2, and neuropilin-1 are expressed to varying degrees in primary breast cancers and have prognostic significance. Further study of the functional significance of this finding is warranted as well as the prognostic value of these biomarkers in other tumor microenvironment-specific compartments (eg, vessels).

Role of prolactin and vasoinhibins in the regulation of vascular function in mammary gland

The formation of new blood vessels has become a major focus of mammary gland research stimulated by the therapeutic opportunities of controlling angiogenesis in breast cancer. Normal growth and involution of the mammary gland are profoundly affected by the expansion and regression of blood vessels, whereas dysregulation of angiogenesis is characteristic of breast cancer growth and metastasis. Prolactin stimulates the growth and differentiation of the mammary gland under normal conditions, but its role in breast cancer is controversial. Its action is complicated by the fact that prolactin itself is angiogenic, but proteases cleave prolactin to generate vasoinhibins, a family of peptides that act on endothelial cells to suppress angiogenesis and vasodilation and to promote apoptosis-mediated vascular regression. This review summarizes our current knowledge about the vascular effects of prolactin and the generation and action of vasoinhibins, and discusses their possible contribution to the regulation of blood vessels in the normal and malignant mammary gland.

Bevacizumab and albumin-bound paclitaxel treatment in metastatic breast cancer

BACKGROUND

Miller et al demonstrated that the combination of bevacizumab and paclitaxel has significant activity in metastatic breast cancer (MBC). Because albumin-bound paclitaxel has been shown to have less toxicity, a better tumor delivery, and possibly better response for MBC, we combined it with bevacizumab to treat women with MBC.

PATIENTS AND METHODS

This is a retrospective analysis. Billing records from March 2005 through December 2006 were reviewed to identify all patients treated with a combination of albumin-bound paclitaxel/bevacizumab. A total of 40 women were identified. They received a minimum of 2 courses. Patients with measurable disease were monitored for response using Response Evaluation Criteria in Solid Tumors. Women with bone-only disease were monitored with positron emission tomography (PET)/computed tomography/magnetic resonance imaging and tumor markers. All response data were confirmed by independent review.

RESULTS

Of 33 women with measurable disease, 16 had objective responses to the albumin-bound paclitaxel/bevacizumab regimen (3 complete responses and 13 partial responses) for an overall response rate (ORR) of 48.5%. Median time to progression for responders was 128 days. Another 5 women had stable disease (SD) with a median duration of 135 days. Of 7 patients with bone-only disease, 2 had almost complete resolution of PET activity and 4 had SD (median, 148 days). Toxicity was acceptable with fatigue, neuropathy, pain, and hypertension being the most common complaints.

CONCLUSION

In our limited series of women with advanced, heavily pretreated MBC treated with albumin-bound paclitaxel/bevacizumab, we saw a 48.5% ORR. The regimen was well tolerated. Randomized studies are needed to confirm efficacy and safety of this combination in treating breast cancer.

Human chorionic gonadotropin as an angiogenic factor in breast cancer during pregnancy

Breast cancer associated with pregnancy is defined as the one in which the diagnosis is made in a pregnancy or within one year of delivery. Breast cancer is the second most common malignancy during pregnancy and it is generally considered to have a worse prognosis than the one that is not associated with pregnancy. The average patient is between 32 and 38 years of age. Steroid hormone receptor-positive cell populations comprise 80% of breast cancers, however, estrogen receptor levels in pregnancy-associated tumors are often low or absent. Extensive laboratory data suggest that angiogenesis plays an essential role in breast cancer development, invasion, and metastasis. One of the most powerful stimulatory factors, vascular endothelial growth factor (VEGF), functions in autocrine/paracrine pathways. Current research, generally has validated the poor prognosis and early relapse that are associated with increasing microvessel density, which is related to VEGF expression in tumoral cells. During pregnancy, human chorionic gonadotropin (hCG) induces neovascularization in various tissues, one of them being the placenta. Its receptors have been detected in epithelial cells in breast carcinoma tissue, and breast cancer cell lines. According to this premise the hCG normally produced during pregnancy could induce the synthesis of VEGF and by this means stimulate the development and metastatic potential of breast cancer cells in the pregnancy period. Thus, research involving hCG and VEGF would help us understand the physiopathology of breast cancer during pregnancy, as well as provide us with probable prognostic tools.