Effects of oestradiol and tamoxifen on VEGF, soluble VEGFR-1, and VEGFR-2 in breast cancer and endothelial cells

Synergistic effects of bee venom, hesperidin, and piperine with tamoxifen on apoptotic and angiogenesis biomarker molecules against xerographic MCF-7 injected rats

Breast cancer ranks as the second leading most significant of mortality for women. Studies have demonstrated the potential benefits of natural compounds in cancer treatment and prevention, either in isolation or in conjunction with chemotherapy. In order to improve Tamoxifen's therapeutic efficacy in in-vivo studies, our research sought to determine the effects of hesperidin, piperine, and bee venom as natural compounds, as well as their combination effect with or without Tamoxifen. First, 132 female albino rats were equally divided into six groups and five subgroups, and breast cancer was induced in the selected groups by xenografting of MCF7 cells. Second, the effect of single and best ratio combinations treatment from previous in vitro studies were selected. Next, tumorous mammary glands were collected for apoptotic and antiapoptotic biomarkers and cell cycle analysis. Single or combined natural products with or without Tamoxifen revealed a significant up-regulation in apoptotic genes Bax and Casp3 and a downregulation of antiapoptotic and angiogenesis genes Bcl-2 and VEGF genes. We found that cell cycle arrest in the G0/G1 phase was exclusively caused by Tamoxifen and/ or hesperidin. However, the cell cycle arrest in the G2/M phase is a result of the combination of piperine and bee venom, with or without Tamoxifen by using the flow cytometric technique. Our research concludes that bee venom, hesperidin, and piperine can synergistically enhance to increase Tamoxifen's efficiency in the management of breast cancer.

Reprogramming of endothelial gene expression by tamoxifen inhibits angiogenesis and ERα-negative tumor growth

Rationale: 17β-estradiol (E2) can directly promote the growth of ERα-negative cancer cells through activation of endothelial ERα in the tumor microenvironment, thereby increasing a normalized tumor angiogenesis. ERα acts as a transcription factor through its nuclear transcriptional AF-1 and AF-2 transactivation functions, but membrane ERα plays also an important role in endothelium. The present study aims to decipher the respective roles of these two pathways in ERα-negative tumor growth. Moreover, we delineate the actions of tamoxifen, a Selective Estrogen Receptor Modulator (SERM) in ERα-negative tumors growth and angiogenesis, since we recently demonstrated that tamoxifen impacts vasculature functions through complex modulation of ERα activity. Methods: ERα-negative B16K1 cancer cells were grafted into immunocompetent mice mutated for ERα-subfunctions and tumor growths were analyzed in these different models in response to E2 and/or tamoxifen treatment. Furthermore, RNA sequencings were analyzed in endothelial cells in response to these different treatments and validated by RT-qPCR and western blot. Results: We demonstrate that both nuclear and membrane ERα actions are required for the pro-tumoral effects of E2, while tamoxifen totally abrogates the E2-induced in vivo tumor growth, through inhibition of angiogenesis but promotion of vessel normalization. RNA sequencing indicates that tamoxifen inhibits the E2-induced genes, but also initiates a specific transcriptional program that especially regulates angiogenic genes and differentially regulates glycolysis, oxidative phosphorylation and inflammatory responses in endothelial cells. Conclusion: These findings provide evidence that tamoxifen specifically inhibits angiogenesis through a reprogramming of endothelial gene expression via regulation of some transcription factors, that could open new promising strategies to manage cancer therapies affecting the tumor microenvironment of ERα-negative tumors.

Interaction of Some Amino-Nitrile Derivatives with Vascular Endothelial Growth Factor Receptor 1 (VEGFR1) Using a Theoretical Model

BACKGROUND

Some studies indicate that the angiogenesis process is related to vascular endothelial growth factor, which can interact with endothelial cell surface receptors (VEGF-R1, VEGF-R2, and VEGF-R3); this biochemical process and other factors result in the promotion and growth of new blood vessels under normal conditions. However, some studies indicate that this phenomenon could also occur in cancer cells. It is important to mention that some amino derivatives have been prepared as VEGF-R1 inhibitors; however, their interaction with VEGF-R1 is not clear, perhaps due to different experimental approaches or differences in their chemical structure.

OBJECTIVE

The aim of this study was to evaluate the theoretical interaction of several amino-nitrile derivatives (Compounds 1 to 38) with VEGF-R1.

METHODS

The theoretical interaction of amino-nitrile derivatives with VEGF-R1 was carried out using the 3hng protein as the theoretical model. In addition, cabozantinib, pazopanib, regorafenib, and sorafenib were used as controls in the DockingServer program.

RESULTS

The results showed different amino acid residues involved in the interaction of amino-nitrile derivatives with the 3hng protein surface compared with the controls. In addition, the inhibition constant (Ki) was lower for Compounds 10 and 34 than for cabozantinib. Other results show that Ki for Compounds 9, 10, 14, 27-29 and 34-36 was lower in comparison with pazopanib, regorafenib, and sorafenib.

CONCLUSIONS

All theoretical data suggest that amino-nitrile derivatives could produce changes in the growth of some cancer cell lines through VEGFR-1 inhibition. Therefore, these amino-nitrile derivatives could be a therapeutic alternative to treat some types of cancer.

New Advances in Targeted Therapy of HER2-Negative Breast Cancer

Breast cancer has an extremely high incidence in women, and its morbidity and mortality rank first among female tumors. With the increasing development of molecular biology and genomics, molecular targeted therapy has become one of the most active areas in breast cancer treatment research and has also achieved remarkable achievements. However, molecular targeted therapy is mainly aimed at HER2-positive breast cancer and has not yet achieved satisfactory curative effect on HER2-negative breast cancer. This article describes the potential targets that may be used for breast cancer treatment from the aspects of PI3K/AKT signaling pathway, DDR, angiogenesis, the cell cycle, breast cancer stem cells, etc., and explores possible inhibitors for the treatment of HER2-negative breast cancer, such as PI3K inhibitors, AKT inhibitors and m-TOR inhibitors that inhibit the PI3K/AKT signaling pathway, small molecule tyrosine kinase inhibitors that restrain angiogenesis, CDK inhibitors, aurora kinase inhibitors and HDAC inhibitors that block cell cycle, as well as the drugs targeting breast cancer stem cells which have been a hit, aiming to provide a new idea and strategy for the treatment of HER2-negative breast cancer.

Anti-Angiogenic Treatments Interact with Steroid Secretion in Inflammatory Breast Cancer Triple Negative Cell Lines

Human inflammatory breast cancer (IBC) is a highly angiogenic disease for which antiangiogenic therapy has demonstrated only a modest response, and the reason for this remains unknown. Thus, the purpose of this study was to determine the influence of different antiangiogenic therapies on in vitro and in vivo steroid hormone and angiogenic growth factor production using canine and human inflammatory breast carcinoma cell lines as well as the possible involvement of sex steroid hormones in angiogenesis. IPC-366 and SUM149 cell lines and xenotransplanted mice were treated with different concentrations of VEGF, SU5416, bevacizumab and celecoxib. Steroid hormone (progesterone, dehydroepiandrostenedione, androstenedione, testosterone, dihydrotestosterone, estrone sulphate and 17β-oestradiol), angiogenic growth factors (VEGF-A, VEGF-C and VEGF-D) and IL-8 determinations in culture media, tumour homogenate and serum samples were assayed by EIA. In vitro, progesterone- and 17β-oestradiol-induced VEGF production promoting cell proliferation and androgens are involved in the formation of vascular-like structures. In vivo, intratumoural testosterone concentrations were augmented and possibly associated with decreased metastatic rates, whereas elevated E1SO4 concentrations could promote tumour progression after antiangiogenic therapies. In conclusion, sex steroid hormones could regulate the production of angiogenic factors. The intratumoural measurement of sex steroids and growth factors may be useful to develop preventive and individualized therapeutic strategies.

Design, synthesis and biological evaluation of a new thieno[2,3-d]pyrimidine-based urea derivative with potential antitumor activity against tamoxifen sensitive and resistant breast cancer cell lines

Breast cancer (BC) and endocrine resistance to chemotherapy are challenging problems where angiogenesis plays fundamental roles. Thus, targeting of VEGFR-2 signalling pathway has been an attractive approach. In this study, we synthesised a new sorafenib analogue, thieno[2,3-d]pyrimidine based urea derivative, KM6. It showed 65% inhibition of VEGF2 tyrosine kinase activity and demonstrated a potential antitumor activity in TAM-resistant, LCC2, and its parental MCF7 BC cells. KM6 retained the sensitivity of LCC2 through upregulation of key enzymes of apoptosis and proteins of cell death including caspases 3, 8, 9, P53, BAX/BCL-2 ratio and LDH in media. It downregulated mRNA expression of Ki-67, survivin, Akt, and reduced levels of ROS and glucose uptake. Moreover, KM6 reduced the levels of inflammation markers PGE2, COX2, IL-1β and IL6 and metastasis markers MMP-2 and MMP-9. In conclusion, KM6 is a promising compound for ER + and TAM-resistant BC with many potential antitumor and polypharmacological mechanisms.

In vitro studies on inhibition capability of fungal-sourced bassiatin versus tamoxifen against ERα, EGFR and VEGFR on breast cancer cells

Bassiatin which is produced by some fungi, is morpholine-based depsipeptide. Recent studies show that bassiatin inhibits MCF-7 breast cancer cell proliferation with its anti-oestrogenic effect. In this study, bassiatin's inhibition versus Tamoxifen was examined by comparing the effects on epidermal growth factor receptor and vascular endothelial growth factor receptor in addition to oestrogen receptor on breast cells. For this purpose, 15 concentrations of bassiatin, tamoxifen and combination of both were treated in terms of cytotoxicity on MCF-7, MDA-MB-231, SK-BR-3 and SVCT cell lines. For cell cycle analyses, MCF-7 and SVCT cell lines were incubated with 37.5 μM bassiatin, tamoxifen and combined substance for 24 h and 48 h. After treatment, cell distribution in each phase of the cell cycle was measured with flow cytometer. Furthermore, each interaction related to receptors were investigated with immunoassay ELISA kits. As a result, bassiatin-induced MCF-7 cell cycle arrest was shown in G0/G1 and G2/M phases at the presence of bassiatin. It was also found that bassiatin is more effective at all examined receptors on breast cancer cells than tamoxifen. These results show that bassiatin can be used effectively in breast cancer treatment as a new anticancer agent because of its multiple inhibition effects.

Cutaneous and hepatic vascular lesions due to a recurrent somatic GJA4 mutation reveal a pathway for vascular malformation

The term “cavernous hemangioma” has been used to describe vascular anomalies with histology featuring dilated vascular spaces, vessel walls consisting mainly of fibrous stromal bands lined by a layer of flattened endothelial cells, and an irregular outer rim of interrupted smooth muscle cells. Hepatic hemangiomas (HHs) and cutaneous venous malformations (VMs) share this histologic pattern, and we examined lesions in both tissues to identify genetic drivers. Paired whole-exome sequencing (WES) of lesional tissue and normal liver in HH subjects revealed a recurrent GJA4 c.121G>T (p.Gly41Cys) somatic mutation in four of five unrelated individuals, and targeted sequencing in paired tissue from 9 additional HH individuals identified the same mutation in 8. In cutaneous lesions, paired targeted sequencing in 5 VMs and normal epidermis found the same GJA4 c.121G>T (p.Gly41Cys) somatic mutation in three. GJA4 encodes gap junction protein alpha 4, also called connexin 37 (Cx37), and the p.Gly41Cys mutation falls within the first transmembrane domain at a residue highly conserved among vertebrates. We interrogated the impact of the Cx37 mutant via lentiviral transduction of primary human endothelial cells. We found that the mutant induced changes in cell morphology and activated serum/glucocorticoid-regulated kinase 1 (SGK1), a serine/threonine kinase known to regulate cell proliferation and apoptosis, via non-canonical activation. Treatment with spironolactone, an inhibitor of angiogenesis, suppressed mutant SGK1 activation and reversed changes in cell morphology. These findings identify a recurrent somatic GJA4 c.121G>T mutation as a driver of hepatic and cutaneous VMs, revealing a new pathway for vascular anomalies, with spironolactone a potential pathogenesis-based therapy.

Melatonin as an Oncostatic Molecule Based on Its Anti-Aromatase Role in Breast Cancer

Breast cancer is the most common type of cancer. In the developmental stages of breast cancer, estrogens are strongly involved. As estrogen synthesis is regulated by the enzyme aromatase, targeting the activity of this enzyme represents a therapeutic option. The pineal hormone melatonin may exert a suppressive role on aromatase activity, leading to reduced estrogen biosynthesis. A melatonin-mediated decrease in the expression of aromatase promoters and associated genes would provide suitable evidence of this molecule’s efficacy as an aromatase inhibitor. Furthermore, melatonin intensifies radiation-induced anti-aromatase effects and counteracts the unwanted disadvantages of chemotherapeutic agents. In this manner, this review summarizes the inhibitory role of melatonin in aromatase action, suggesting its role as a possible oncostatic molecule in breast cancer.

Diagnostic Value of VEGF-A, VEGFR-1 and VEGFR-2 in Feline Mammary Carcinoma

Vascular endothelial growth factor (VEGF-A) plays an essential role in tumor-associated angiogenesis, exerting its biological activity by binding and activating membrane receptors, as vascular endothelial growth factor receptor 1 and 2 (VEGFR-1, VEGFR-2). In this study, serum VEGF-A, VEGFR-1, and VEGFR-2 levels were quantified in 50 cats with mammary carcinoma and 14 healthy controls. The expression of these molecules in tumor-infiltrating lymphocytes (TILs) and in cancer cells was evaluated and compared with its serum levels. Results obtained showed that serum VEGF-A levels were significantly higher in cats with HER2-positive and Triple Negative (TN) Normal-Like subtypes, when compared to control group (p = 0.001, p = 0.020). Additionally, serum VEGFR-1 levels were significantly elevated in cats presenting luminal A, HER2-positive and TN Normal-Like tumors (p = 0.011, p = 0.048, p = 0.006), as serum VEGFR-2 levels (p = 0.010, p = 0.046, p = 0.005). Moreover, a positive interaction was found between the expression of VEGF-A, VEGFR-1, and VEGFR-2 in TILs and their serum levels (p = 0.002, p = 0.003, p = 0.003). In summary, these findings point to the usefulness of VEGF-A and its serum receptors assessment in clinical evaluation of cats with HER2-positive and TN Normal-Like tumors, suggesting that targeted therapies against these molecules may be effective for the treatment of these animals, as described in human breast cancer.

Adipocytes Promote Early Steps of Breast Cancer Cell Dissemination via Interleukin-8

Fat is a major tissue component in human breast cancer (BC). Whether breast adipocytes (BAd) affect early stages of BC metastasis is yet unknown. BC progression is dependent on angiogenesis and inflammation, and interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) are key regulators of these events. Here, we show that BAd increased the dissemination of estrogen receptor positive BC cells (BCC) in vivo in the zebrafish model of metastasis, while dissemination of the more aggressive and metastatic BCC such as estrogen receptor negative was unaffected. While anti-VEGF and anti-IL-8 exhibited equal inhibition of angiogenesis at the primary tumor site, anti-IL-8 reduced BCC dissemination whereas anti-VEGF had minor effects on this early metastatic event. Mechanistically, overexpression of cell-adhesion molecules in BCC and neutrophils via IL-8 increased the dissemination of BCC. Importantly, the extracellular in vivo levels of IL-8 were 40-fold higher than those of VEGF in human BC. Our results suggest that IL-8 is a clinical relevant and promising therapeutic target for human BC.

Tamoxifen Never Ceases to Amaze: New Findings on Non-Estrogen Receptor Molecular Targets and Mediated Effects

Tamoxifen is a first targeted drug that continues to be the gold standard in treatment of estrogen receptor positive breast cancer for almost 50 years. The current review is an update of the paper published in 2012. We provide the new data on the tamoxifen targets that are the key points of signaling cascades activating cellular proliferation, which determines aggressiveness of disease and chemotherapy resistance or sensitivity. Some inspiring clinical cases dealing with tamoxifen efficiency in treatment of different tumors are discussed. Additionally, the review includes data on antiviral, antibacterial, antifungal and antiparasitic activity of tamoxifen.

A Chip for Estrogen Receptor Action: Detection of Biomarkers Released by MCF-7 Cells through Estrogenic and Anti-Estrogenic Effects

The fluorescence-based multi-analyte chip platform for the analysis of estrogenic and anti-estrogenic substances is a new in vitro tool for the high throughput screening of environmental samples. In contrast to existing tools, the chip investigates the complex action of xenoestrogens in a human cell model by characterizing protein expression. It allows for the quantification of 10 proteins secreted by MCF-7 cells, representing various biological and pathological endpoints of endocrine action and distinguishing between estrogen- and anti-estrogen-dependent secretion of proteins. Distinct protein secretion patterns of the cancer cell line after exposure to known estrogen receptor agonists ß-estradiol, bisphenol A, genistein, and nonylphenol as well as antagonists fulvestrant and tamoxifen demonstrate the potential of the chip. Stimulation of cells with Interleukin-1ß shifts concentrations of low abundant biomarkers towards the working range of the chip. In the non-stimulated cell culture, Matrix Metalloproteinase 9 (MMP-9) and Vascular Endothelial Growth Factor (VEGF) show differences upon treatment with antagonists and agonists of the estrogen receptor. In stimulated MCF-7 cells challenged with receptor agonists secretion of Monocyte Chemoattractant Protein (MCP-1), Interleukin-6 (IL-6), Rantes, and Interleukin-8 (IL-8) significantly decreases. In parallel, the proliferating effect of endocrine-disrupting substances in MCF-7 cells is assessed in a proliferation assay based on resazurin. Using ethanol as a solvent for test substances increases the background of proliferation and secretion experiments, while using dimethyl sulfoxide (DMSO) does not show any adverse effects. The role of the selected biomarkers in different physiological processes such as cell development, reproduction, cancer, and metabolic syndrome makes the chip an excellent tool for either indicating endocrine-disrupting effects in food and environmental samples, or for screening the effect of xenoestrogens on a cellular and molecular level.

Increased nutrient availability in dense breast tissue of postmenopausal women in vivo

Metabolic reprogramming is a hallmark of cancer. Nutrient availability in the tissue microenvironment determines cellular events and may play a role in breast carcinogenesis. High mammographic density is an independent risk factor for breast cancer. Whether nutrient availability differs in normal breast tissues with various densities is unknown. Therefore we investigated whether breast tissues with various densities exhibited differences in nutrient availability. Healthy postmenopausal women from the regular mammographic screening program who had either predominantly fatty breast tissue (nondense), n = 18, or extremely dense breast tissue (dense), n = 20, were included. Microdialysis was performed for the in vivo sampling of amino acids (AAs), analyzed by ultra-high performance liquid chromatography with tandem mass spectroscopy, glucose, lactate and vascular endothelial growth factor (VEGF) in breast tissues and, as a control, in abdominal subcutaneous (s.c.) fat. We found that dense breast tissue exhibited significantly increased levels of 20 proteinogenic AAs and that 18 of these AAs correlated significantly with VEGF. No differences were found in the s.c. fat, except for one AA, suggesting tissue-specific alterations in the breast. Glucose and lactate were unaltered. Our findings provide novel insights into the biology of dense breast tissue that may be explored for breast cancer prevention strategies.

Adipokines and Vascular Endothelial Growth Factor in Normal Human Breast Tissue in Vivo - Correlations and Attenuation by Dietary Flaxseed

Exposure to sex steroids increases the risk of breast cancer but the exact mechanisms are yet to be elucidated. Events in the microenvironment are important for carcinogenesis. Diet containing phytoestrogens can affect the breast microenvironment and alter the risk of breast cancer. It has previously been shown that estrogen regulates extracellular levels of leptin, adiponectin, and VEGF in normal breast tissue in vivo. Whether these proteins correlate in breast tissue in vivo or if diet addition of flaxseed, a major source of phytoestrogens in Western diets, alters adipokine levels in breast tissue are unknown. We used microdialysis to sample proteins of normal human breast tissue and abdominal subcutaneous fat in situ in 34 pre-and postmenopausal women. In vitro, co-culture of breast cancer cells and primary human adipocytes was used. In vivo, in normal breast tissue, a significant positive correlation between VEGF and leptin was detected. No correlations were found in fat tissue. Co-culture of adipocytes and breast cancer cells per se increased the secretion of VEGF and leptin and enhanced the effects of estradiol compared to culture of either cell type alone. In vitro, inhibition of VEGF diminished the release of leptin while inhibition of leptin had no influence on VEGF secretion. The levels of leptin decreased and adiponectin increased after a dietary addition of 25 g of flaxseed/day for one menstrual cycle. We conclude that VEGF and leptin correlate significantly in normal human breast tissue in vivo and that dietary addition of flaxseed affect adipokine levels in the breast.

Hormone Use is Associated with Lymphovascular Invasion in Breast Cancer

BACKGROUND

Risk of developing breast cancer increases with short breastfeeding and the use of hormones. The prognosis of breast cancer is better if the tumours are hormone receptor positive. Since breast feeding affects estrogen and progesterone receptors, we wanted to investigate how such reproductive factors as breastfeeding and the use of hormones interact with known prognostic markers and specific tumour characteristics in women with breast cancer.

MATERIALS AND METHODS

A total of 250 women treated for breast cancer from a larger cohort completed a questionnaire on breastfeeding, number and age at births and use of hormones. A logistic regression analysis was made to search for connections between known prognostic markers on the one hand (type of cancer, grade, tumor size, estrogen receptor and progesterone receptor, lymphovascular invasion and DNA-ploidy) and reproductive data, breastfeeding, and hormone use on the other.

RESULTS AND CONCLUSIONS

Hormone use, but not breastfeeding, was significantly associated, also on multivariate analysis, with the prognostic variable lymphovascular invasion, connected to a worse prognosis. No other hormone use or breast feeding correlations with prognostic variables were found.

Synergistic effects of tamoxifen and tranilast on VEGF and MMP-9 regulation in cultured human breast cancer cells

BACKGROUND

Vascular endothelial growth factor and matrix metalloproteinases are two important factors for angiogenesis associated with breast cancer growth and progression. The present study was aimed to examine the effects of tamoxifen and tranilast drugs singly or in combination on proliferation of breast cancer cells and also to evaluate VEGF and MMP-9 expression and VEGF secretion levels.

MATERIALS AND METHODS

Human breast cancer cell lines, MCF-7 and MDA-MB-231, were treated with tamoxifen and/or tranilast alone or in combination and percentage cell survival and proliferative activity were evaluated using LDH leakage and MTT assays. mRNA expression and protein levels were examined by real-time RT-PCR and ELISA assay, respectively.

RESULTS

LDH and MTT assays showed that the combined treatment of tamoxifen and tranilast resulted in a significant decrease in cell viability and cell proliferation compared with tamoxifen or tranilast treatment alone, with significant decrease in VEGF mRNA and protein levels. We also found that tamoxifen as a single agent rarely increased MMP-9 expression. A decrease in MMP-9 expression was seen after treatment with tranilast alone and in the combined treatment MMP-9 mRNA level was decreased.

CONCLUSIONS

This combination treatment can able to inhibit growth, proliferation and angiogenesis of breast cancer cells.

COX-2 silencing enhances tamoxifen antitumor activity in breast cancer in vivo and in vitro

Tamoxifen (Tam), a selective estrogen receptor modulator, is in wide clinical use for the treatment and prevention of breast cancer. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy and highlighting the need for improved therapeutic strategies. Cyclooxygenase-2 (COX-2) silencing via a replication-incompetent lentivirus (LV-COX-2) induce cancer apoptosis and suppresses VEGF gene expression. In this study, the effect of LV-COX-2 infection, either alone or in combination with TAM, was analyzed in a breast cell lines for suppressing VEGF expression and simultaneously reducing doses of TAM. Cell proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, an receptor signaling were determined after LV-COX-2 combination with TAM treatment. In addition, tumor growth ability in nude mice was detected to define the combination treatment effect in tumorigenesis in vivo. It is found that LV-COX-2 combination with TAM treatment in breast cancer cell significantly suppressed the proliferation and metastasis, and induced tumor apoptosis in vitro, and tumor growth also was suppressed in vivo. In addition, we also found that LV-COX-2 combination with TAM treatment could inhibit angiogenesis and VEGF expression. Taken together, our experimental results indicate that LV-COX-2 combination with TAM has promising outcome in anti-metastatic and apoptotic studies. Furthermore, these results showed that LV-COX-2 combination with TAM is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF.

Association of positive EBAG9 immunoreactivity with unfavorable prognosis in breast cancer patients treated with tamoxifen

INTRODUCTION

Breast cancer is primarily a hormone-dependent tumor that is regulated by the status of the estrogen and progesterone receptors. We previously identified EBAG9 as an estrogen-responsive gene in MCF-7 human breast carcinoma cells. Upregulation of EBAG9 expression has been observed in several malignant tumors such as advanced breast cancers, indicating that EBAG9 might contribute to tumor progression.

PATIENTS AND METHODS

In the present study, we generated a monoclonal antibody against EBAG9, and then performed immunohistochemical analysis of EBAG9 expression in specimens obtained from breast cancer patients treated with tamoxifen as an adjuvant therapy.

RESULTS

EBAG9 immunoreactivity was detected in the cytoplasm of breast cancer cells and was significantly elevated in breast cancer samples from patients who relapsed during or after adjuvant tamoxifen treatment. Positive EBAG9 immunoreactivity was significantly correlated with poor patient prognosis.

CONCLUSION

These results suggest that EBAG9 expression in tumor regions is associated with an unfavorable prognosis in breast cancer patients treated with tamoxifen.

Celecoxib alleviates tamoxifen-instigated angiogenic effects by ROS-dependent VEGF/VEGFR2 autocrine signaling

BACKGROUND

Tamoxifen (TAM) is widely used in the chemotherapy of breast cancer and as a preventive agent against recurrence after surgery. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy. Celecoxib (CXB), a selective COX-2 inhibitor, suppresses VEGF gene expression by targeting the VEGF promoter responsible for its inhibitory effect. For this study, we had selected CXB as non-steroidal anti-inflammatory drug in combination with TAM for suppressing VEGF expression and simultaneously reducing doses of both the drugs.

METHODS

The effects of CXB combined with TAM were examined in two human breast cancer cell lines in culture, MCF7 and MDA-MB-231. Assays of proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, and receptor signaling were performed.

RESULTS

Here, we elucidated how the combination of TAM and CXB at nontoxic doses exerts anti-angiogenic effects by specifically targeting VEGF/VEGFR2 autocrine signaling through ROS generation. At the molecular level, TAM-CXB suppresses VHL-mediated HIF-1α activation, responsible for expression of COX-2, MMP-2 and VEGF. Besides low VEGF levels, TAM-CXB also suppresses VEGFR2 expression, confirmed through quantifying secreted VEGF levels, luciferase and RT-PCR studies. Interestingly, we observed that TAM-CXB was effective in blocking VEGFR2 promoter induced expression and further 2 fold decrease in VEGF levels was observed in combination than TAM alone in both cell lines. Secondly, TAM-CXB regulated VEGFR2 inhibits Src expression, responsible for tumor progression and metastasis. FACS and in vivo enzymatic studies showed significant increase in the reactive oxygen species upon TAM-CXB treatment.

CONCLUSIONS

Taken together, our experimental results indicate that this additive combination shows promising outcome in anti-metastatic and apoptotic studies. In a line, our preclinical studies evidenced that this additive combination of TAM and CXB is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF and VEGFR2. This ingenious combination might be a better tailored clinical regimen than TAM alone for breast cancer treatment.

Melatonin modulates aromatase activity and expression in endothelial cells

Melatonin is known to suppress the development of endocrine-responsive breast cancers by interacting with the estrogen signaling pathways. Paracrine interactions between malignant epithelial cells and proximal stromal cells are responsible for local estrogen biosynthesis. In human breast cancer cells and peritumoral adipose tissue, melatonin downregulates aromatase, which transforms androgens into estrogens. The presence of aromatase on endothelial cells indicates that endothelial cells may contribute to tumor growth by producing estrogens. Since human umbilical vein endothelial cells (HUVECs) express both aromatase and melatonin receptors, the aim of the present study was to evaluate the ability of melatonin to regulate the activity and expression of aromatase on endothelial cells, thus, modulating local estrogen biosynthesis. In the present study, we demonstrated that melatonin inhibits the growth of HUVECs and reduces the local biosynthesis of estrogens through the downregulation of aromatase. These results are supported by three lines of evidence. Firstly, 1 mM of melatonin counteracted the testosterone-induced cell proliferation of HUVECs, which is dependent on the local biosynthesis of estrogens from testosterone by the aromatase activity of the cells. Secondly, we found that 1 mM of melatonin reduced the aromatase activity of HUVECs. Finally, by real‑time RT-PCR, we demonstrated that melatonin significantly downregulated the expression of aromatase as well as its endothelial-specific aromatase promoter region I.7. We conclude that melatonin inhibits aromatase activity and expression in HUVECs by regulating gene expression of specific aromatase promoter regions, thereby reducing the local production of estrogens.

Effect of tamoxifen, methoxyprogesterone acetate and combined treatment on cellular proliferation and apoptosis in SKOV3/DDP cells via the regulation of vascular endothelial growth factor

PURPOSE

The aim of this study was to investigate the effect of tamoxifen (TAM), methoxyprogesterone acetate (MPA) and their combined treatment on cisplatin-resistant ovarian cancer SKOV3/DDP cells, as well as the potential mechanisms.

METHODS

MTT assay was used to investigate the effect of different concentrations (0.01, 0.1, 1, 10 and 100 μM) of TAM, MPA and their combined treatment on the proliferation of cisplatin-resistant ovarian cancer SKOV3/DDP cells. Flow cytometry was employed to analyze the cell cycle and apoptosis rate of SKOV3/DDP cells treated with medium concentration (10 μM) of TAM, MPA and their combined treatment. Change in the protein level of vascular endothelial growth factor (VEGF) in response to drug treatments was measured using Western-blot.

RESULTS

The proliferation of SKOV3/DDP cells was inhibited by 1, 10 and 100 μM of TAM or MPA in a dose-dependent manner. Compared to the control group, 10 μM TAM could significantly arrest SKOV3/DDP cells in the G0/G1 stage and induce apoptosis (p < 0.01). However, 10 μM MPA only promoted cell apoptosis, while exhibited little effect on the cell cycle. We further found that 10 μM TAM could remarkably reduce the protein expression of VEGF, while 10 μM MPA only induce a slight reduction. Strikingly, the combined treatment of TAM and MPA exhibited additive effect on the proliferation, cell cycle, apoptosis rate and VEGF expression of SKOV3/DDP cells.

CONCLUSIONS

We found that TAM, MPA and their combined treatment exhibited significant inhibitory effect on the cisplatin-resistant ovarian cancer SKOV3/DDP cells. Hence, TAM and MPA could be potential cytotoxic drugs to treat cisplatin-resistant patients with advanced ovarian cancer.

Successful management of multi-focal hepatic infantile hemangioendothelioma using TACE/surgery followed by maintenance metronomic therapy

Infantile hepatic hemangioendothelioma (IHE) is a rare angiogenic tumour with diverse clinical presentations and varied course ranging from spontaneous regression to life-threatening complications. The authors report a 2-year boy who presented with respiratory distress and was identified as a case of inoperable multi-focal hepatic IHE. He showed a transient response to trans-arterial-chemo-embolisation and liver resection but had progressive disease despite chemotherapy (prednisolone/vicristine/ifosfamide/cisplatin). Thereafter, he was successfully managed with metronomic therapy using cyclophosphamide and tamoxifen.

Seed, soil and secreted hormones: potential interactions of breast cancer cells with their endocrine/paracrine microenvironment and implications for treatment with bisphosphonates

The process of formation of metastasis is undoubtedly inefficient, with the majority of disseminated tumour cells perishing in their metastatic environment. Their ability to survive is determined by their intrinsic abilities, with emerging evidence of the importance of cancer stem cells possessing self propagating potential, but also the interaction with the premetastatic niche, which may either help or hinder their formation into micrometastasis, thus influencing recurrence and survival in breast cancer patients. Use of the bone targeted agents bisphosphonates in the adjuvant setting has been extensively studied in large clinical trials, and demonstrated an interesting interplay with the endocrine microenvironment, with postmenopausal women or premenopausal women receiving ovarian suppression therapy gaining a survival advantage compared to pre/perimenopausal women. The interaction between the endocrine hormones and the paracrine TGFβ growth factors may provide an explanation for the differences seen according to ovarian function in the response to bisphosphonates. In this review the evidence of interplay between ovarian endocrine hormones, TGFβ paracrine growth factors and bisphosphonates will be presented, and subsequent influence on breast cancer cells in the bone pre-metastatic niche hypothesised.

Breast cancer and spider telangiectasias at diagnosis and its relation to histopathology and prognosis: a population-based study

Angiogenesis is one of the hallmarks of breast cancer. The status of angiogenesis is important in therapy choice. Spider telangiectasias (telangiectasias) may reflect an increased ability to form vessels. Our first aim was to identify patient and tumor characteristics associated with the occurrence of telangiectasias at the time of breast cancer diagnosis. The second aim was to study the overall survival in relation to the occurrence of telangiectasias at the time of breast cancer diagnosis. A standardized questionnaire was used to interview 1682 consecutive breast cancer patients about risk factors between 1980 and 2009. Occurrence of telangiectasias at the time of breast cancer diagnosis on the upper thorax, head, and/or neck was recorded by one physician. In the cohort, 93 women (5.5%) had telangiectasias. Occurrence of telangiectasias was positively associated with weight, odds ratio (OR) 1.02 (95% confidence interval (CI) 1.00-1.05) per kg, ever-use of oral contraceptives OR 2.67(CI 1.55-4.63) and hormone replacement therapy OR 2.68(CI 1.63-4.39), and negatively associated with parity OR 0.45(CI 0.25-0.79). Telangiectasias were not present in patients with comedo breast cancer. Patients with occurrences of telangiectasias diagnosed before the age of 50 had a statistically non-significant worse overall survival, whereas the patients with occurrences of telangiectasias diagnosed at age 50 or after had a statistically significant better overall survival (P interaction = 0.016). The relationship between the occurrence of telangiectasias and the overall survival in the older patient-group was independent of ever-use of HRT. Hormonal risk factors for breast cancer were associated with the occurrence of spider telangiectasias. The occurrence of telangiectasias may reflect the angiogenic status of the tumor. We hypothesize that telangiectasias could be used as selection criteria for anti-angiogenic therapy in younger breast cancer patients. Therefore, patients with comedo breast cancers maybe a group that may benefit less from anti-angiogenic therapy.

KX-01, a novel Src kinase inhibitor directed toward the peptide substrate site, synergizes with tamoxifen in estrogen receptor α positive breast cancer

KX-01 is the first clinical Src inhibitor of the novel peptidomimetic class that targets the peptide substrate site of Src providing more specificity toward Src kinase. The present study was designed to evaluate the effects of KX-01 as a single agent and in combination with tamoxifen (TAM) on cell growth and apoptosis of ERα positive breast cancer in vitro and in vivo. Flow cytometry demonstrated that KX-01 induced cell cycle arrest in G2/M phase. Immunofluorescent staining for mitotic phase markers and TUNEL staining indicated that cells had arrested in the mitotic phase and mitotic arrested cells were undergoing apoptosis. KX-01 induced nuclear accumulation of cyclin B1, and activation of CDK1, MPM2, and Cdc25C that is required for progression past the G2/M checkpoint. Apoptosis resulted from activation of caspases 6, 7, 8, and 9. Combinational index analysis revealed that combinations of KX-01 with TAM resulted in synergistic growth inhibition of breast cancer cell lines. KX-01 combined with TAM resulted in decreased ERα phosphorylation at Src-regulated phosphorylation sites serines 118 and 167 that were associated with reduced ERα transcriptional activity. Orally administered KX-01 resulted in a dose dependent growth inhibition of MCF-7 tumor xenografts, and in combination with TAM exhibited synergistic growth inhibition. Immunohistochemical analysis revealed that combinational treatment reduced angiogenesis, and ERα signaling in tumors compared to either drug alone that may underlie the synergistic tumor growth inhibition. Combinations of KX-01 with endocrine therapy present a promising new strategy for clinical management of ERα positive breast cancer.

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.

Anti-angiogenic effect of tamoxifen combined with epirubicin in breast cancer patients

Vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor receptor 2 (VEGFR2) are the key factors mediating neo-vascularization. They are often coexpressed in breast cancer. Sex steroids may stimulate angiogenesis via the estrogen receptor (ER) pathway. We investigated to compare the effects of the addition of tamoxifen to epirubicin versus epirubicin alone on VEGF and VEGFR2 expression in breast cancer patients. The expression of VEGF and VEGFR2 was assessed on tissue microarray by immunohistochemistry at baseline conditions and after treatments in the case of 191 patients with T2-4 N0-1 breast cancer enrolled in a randomized trial comparing four cycles of single agent epirubicin versus epirubicin plus tamoxifen as primary systemic treatment. Epirubicin alone failed to induce changes in VEGF expression (P = 0.54), while the addition of tamoxifen to epirubicin resulted in a significant reduction in VEGF expression (P < 0.001). As a consequence, baseline VEGF had a negative prognostic role in patients who received epirubicin alone but not in patients receiving epirubicin plus tamoxifen (interaction test P < 0.05). VEGFR2 expression increased at residual tumor histology in both treatment arms, with a lesser extent in patients receiving tamoxifen plus epirubicin. Decrease in VEGFR2 expression was significantly associated with response rate (P = 0.02). The addition of tamoxifen to epirubicin resulted in a suppression of a key angiogenic pathway. These data suggest a potential synergism of these two drugs.

Estradiol stimulates capillary formation by human endothelial progenitor cells: role of estrogen receptor-{alpha}/{beta}, heme oxygenase 1, and tyrosine kinase

Endothelial progenitor cells (EPCs) repair damaged endothelium and promote capillary formation, processes involving receptor tyrosine kinases (RTKs) and heme oxygenase 1 (HO-1). Because estradiol augments vascular repair, we hypothesize that estradiol increases EPC proliferation and capillary formation via RTK activation and induction of HO-1. Physiological concentrations of estradiol (10 nmol/L) increased EPC-induced capillary sprout and lumen formation in matrigel/fibrin/collagen systems. Propyl-pyrazole-triol (PPT; 100 nmol/L; estrogen receptor [ER]-alpha agonist), but not diarylpropionitrile (ER-beta agonist), mimicked the stimulatory effects of estradiol on capillary formation, and methyl-piperidino-pyrazole (ER-alpha antagonist) abolished the effects of estradiol and PPT. Three different RTK activators (vascular endothelial growth factor, hepatocyte growth factor, and stromal derived growth factor 1) mimicked the capillary-stimulating effects of estradiol and PPT. SU5416 (RTK inhibitor) blocked the stimulatory effects of estradiol and PPT on capillary formation. Estradiol increased HO-1 expression by 2- to 3-fold, an effect blocked by SU5416, and PPT mimicked the effects of estradiol on HO-1. The ability of estradiol to enhance capillary formation, increase expression of HO-1, and augment phosphorylation of extracellular signal-regulated kinase 1/2, Akt, and vascular endothelial growth factor receptor 2 was mimicked by its cell-impermeable analog BSA estradiol. Actinomycin (transcription inhibitor) did not alter the effects of estradiol on RTK activity or vascular endothelial growth factor secretion. We conclude that estradiol via ER-alpha promotes EPC-mediated capillary formation by a mechanism that involves nongenomic activation of RTKs and HO-1 activation. Estradiol in particular and ER-alpha agonists in general may promote healing of injured vascular beds by promoting EPC activity leading to more rapid endothelial recovery and capillary formation after injury.

Estrogen-induced angiogenic factors derived from stromal and cancer cells are differently regulated by enterolactone and genistein in human breast cancer in vivo

Angiogenesis is a key in cancer progression and its regulators are released both by the tumor cells and the stroma. Dietary phytoestrogens, such as the lignan enterolactone (ENL) and the isoflavone genistein (GEN), may differently affect breast cancer growth. In this study, human breast cancer cells (MCF-7) were established in mice creating a tumor with species-specific cancer and stroma cells. Ovariectomized athymic mice supplemented with estradiol (E2) were fed basal AIN-93G diet (BD) or BD supplemented with 100 mg/kg ENL, 100 mg/kg GEN or their combination (ENL+GEN). We show that ENL and ENL+GEN inhibited E2-induced cancer growth and angiogenesis, whereas GEN alone did not. Microdialysis was used to sample extracellular proteins in tumors in vivo. ENL and ENL+GEN decreased both stroma- and cancer cell-derived VEGF, whereas cancer cell-derived PlGF increased. In subcutaneous Matrigel plugs in mice, ENL and ENL+GEN decreased E2-induced endothelial cell infiltration, whereas GEN alone did not. In endothelial cells, ENL inhibited E2-induced VEGFR-2 expression, whereas GEN did not. These results suggest that ENL has potent effects on breast cancer growth, even in combination with GEN, by downregulating E2-stimulated angiogenic factors derived both from the stroma and the cancer cells, whereas dietary GEN does not possess any antiestrogenic effects.

Angiogenesis-associated sequence variants relative to breast cancer recurrence and survival

INTRODUCTION

Breast cancer (BrCA) risk stratification using clinico-pathological biomarkers helps improve disease prognosis prediction. However, disease recurrence rates remain unfavorable and individualized clinical management strategies are needed. Consequently, we evaluated the influence of 14 sequence variants detected in IL-10, TGF-β1, VEGF, and their associated receptors as effective predictors of BrCA clinical outcomes.

METHODS

Tumor DNA samples collected from 441 BrCA patients were genotyped using TaqMan-PCR. Most selected targets alter cytokine serum/plasma levels or signaling pathways. Relationships between genetic profiles and recurrence as well as disease-related mortality were evaluated using cumulative incidence curves and competing risk regression models.

RESULTS

The VEGF(-2578)C allele was associated with a 1.3- to 1.6-fold increase in BrCA recurrence (HR(trend) = 1.28; 95% CI = 0.96-1.72) and disease-related mortality (HR(trend) = 1.56; 95% CI = 0.93-2.56). Although this marker was marginally significant relative to BrCA outcomes, there were substantial gains in the 5- and 8-year predictive accuracy compared to standard prognostic indicators. Among ER(+)/PR(+) status patients, there was a significant impact of the VEGF(-2578)CC genotype on disease recurrence and predictive accuracy.

CONCLUSIONS

Our findings suggest inheritance of the VEGF(-2578)C allele could serve as an independent prognostic indicator of BrCA prognosis. The VEGF(-2578) marker may have clinical implications among a subset of ER(+)/PR(+) patients with an aggressive phenotype. Because the VEGF(-2578)C allele is linked to high VEGF expression, this cytokine is a potential prognostic and targeted clinical management tool.

Angiogenin regulation by estradiol in breast tissue: tamoxifen inhibits angiogenin nuclear translocation and antiangiogenin therapy reduces breast cancer growth in vivo

PURPOSE

Angiogenin, a 14.2-kDa polypeptide member of the RNase A superfamily, has potent angiogenic effects. Nuclear accumulation of angiogenin is essential for its angiogenic activity. Increased angiogenin expression has been associated with the transition of normal breast tissue into invasive breast carcinoma. In this article, we investigated whether estradiol (E(2)) affected angiogenin in breast tissue.

EXPERIMENTAL DESIGN

We used microdialysis for sampling of extracellular angiogenin in vivo. In vitro cultures of whole normal breast tissue, breast cancer cells, and endothelial cells were used.

RESULTS

We show that extracellular angiogenin correlated significantly with E(2) in normal human breast tissue in vivo and that exposure of normal breast tissue biopsies to E(2) stimulated angiogenin secretion. In breast cancer patients, the in vivo angiogenin levels were significantly higher in tumors compared with the adjacent normal breast tissue. In estrogen receptor-positive breast cancer cells, E(2) increased and tamoxifen decreased angiogenin secretion. Moreover, E(2)-induced angiogenin derived from cancer cells significantly increased endothelial cell proliferation. Tamoxifen reversed this increase as well as inhibited nuclear translocation of angiogenin. In vivo, in experimental breast cancer, tamoxifen decreased angiogenin levels and decreased angiogenesis. Additionally, treating tumor-bearing mice with an antiangiogenin antibody resulted in tumor stasis, suggesting a role for angiogenin in estrogen-dependent breast cancer growth.

CONCLUSION

Our results suggest previously unknown mechanisms by which estrogen and antiestrogen regulate angiogenesis in normal human breast tissue and breast cancer. This may be important for estrogen-driven breast cancer progression and a molecular target for therapeutic interventions.

Vascular Endothelial Growth Factor, Soluble Fms-Like Tyrosine Kinase 1, and the Severity of Coronary Artery Disease

Background: The association between vascular endothelial growth factor (VEGF), soluble fms-like tyrosine kinase 1 (sFlt-1), and coronary artery disease (CAD) was investigated. Methods: We enrolled 112 hypertensive patients with proven CAD and 112 hypertensive controls matched for age and gender. The severity of CAD was assessed by the most severe clinical presentation of CAD in patients’ history and by the number of diseased vessels. Results: Vascular endothelial growth factor level was lower, whereas sFlt-1 level was higher in the CAD group compared to the controls. Diabetes mellitus (P = .001), smoking (P = .004), and higher sFlt-1 level (P = .01) were independently associated with CAD. Younger age (P = .02), smoking (P = .049), and higher VEGF levels (P = .02) were independently associated with a history of myocardial infarction (MI), whereas higher sFlt-1 level (P = .01) was independently associated with multivessel disease. Conclusion: Plasma sFlt-1 levels are positively associated with the presence of CAD and are associated with angiographical severity of CAD.

HEXIM1 modulates vascular endothelial growth factor expression and function in breast epithelial cells and mammary gland

Recently, we found that mutation of the C-terminus of transcription factor Hexamethylene bisacetamide inducible protein 1 (HEXIM1) in mice leads to abnormalities in cardiovascular development due to aberrant vascular endothelial growth factor (VEGF) expression. HEXIM1 regulation of some genes has also been shown to be positive transcription elongation factor b (P-TEFb)-dependent. However, it is not known whether HEXIM1 regulates VEGF in the mammary gland. We demonstrate that HEXIM1 regulates estrogen-induced VEGF transcription via inhibition of Estrogen Receptor alpha recruitment to the VEGF promoter in a P-TEFb-independent manner in MCF-7 cells. Under hypoxic conditions, HEXIM1 inhibits estrogen-induced Hypoxia-inducible factor-1 alpha (HIF-1α) protein expression and recruitment of HIF-1α to the hypoxia response element in the VEGF promoter. In the mouse mammary gland, increased HEXIM1 expression decreased estrogen-driven VEGF and HIF-1α expression. Conversely, a mutation in the C-terminus of HEXIM1 (HEXIM1_1-312) led to increased VEGF and HIF-1α expression and vascularization in mammary glands of heterozygous HEXIM1_1-312 mice when compared to their wild-type littermates. Additionally, HEXIM1_1-312 mice have a higher incidence of carcinogen-induced mammary tumors with increased vascularization, suggesting an inhibitory role for HEXIM1 during angiogenesis. Taken together, our data provide evidence to suggest a novel role for HEXIM1 in cancer progression.

Prolonged tamoxifen treatment increases relapse-free survival for patients with primary breast cancer expressing high levels of VEGF

Previous retrospective studies have shown that high intratumoural levels of vascular endothelial growth factor (VEGF) correlate with an inferior outcome for patients treated with adjuvant tamoxifen. Our objectives were to validate the impact of VEGF on survival after adjuvant tamoxifen and to investigate the interaction between VEGF and treatment duration. For this purpose tumour homogenates from 402 patients with operable oestrogen receptor positive breast cancer (BC), treated with tamoxifen for 2 (n=149) or 5 years (n=253) as the only systemic adjuvant therapy were included. The median follow-up time for surviving patients was 9.8 years (range 0.5-14.8 years). Expression of VEGF was assessed by an enzyme-linked immunosorbent assay and investigated in relation to the standard BC parameters and survival. In the total population, higher VEGF was significantly correlated with shorter recurrence-free survival (RFS) (HR=1.63, 95%CI=1.11-2.39, p=0.010), breast cancer corrected survival (BCCS) (HR=1.82, 95%CI=1.13-2.93, p=0.014) and overall survival (OS) (HR=1.51, 95%CI=1.11-2.05, p=0.009). High VEGF was significantly associated with reduced RFS (HR=2.61, 95%CI=1.45-4.70, p=0.001) after two years of tamoxifen, whilst no difference was seen in patients treated for five years (HR=1.09, 95%CI=0.64-1.84, p=0.760). A statistically significant interaction was observed between high VEGF expression and improved RFS after 5-year tamoxifen (p=0.034). In concordance with previous studies, high VEGF was significantly correlated with shorter survival. We present data not reported previously revealing that patients expressing high levels of VEGF display a better outcome provided that tamoxifen is given for five years. Further studies on the impact of VEGF on a 5-year regimen are motivated.

Estrogen and selective estrogen receptor modulators regulate vascular endothelial growth factor and soluble vascular endothelial growth factor receptor 1 in human endometrial stromal cells

OBJECTIVE

To determine whether 17beta-estradiol (E(2)) and selective estrogen receptor modulators can regulate vascular endothelial growth factor (VEGF) and soluble VEGF receptor 1 (sVEGFR-1) as a VEGF antagonist in human endometrial stromal cells (ESCs).

DESIGN

In vitro experiment.

SETTING

Research laboratory at Kansai Medical University.

PATIENT(S)

Sixteen patients undergoing hysterectomy for benign reasons.

INTERVENTION(S)

The ESCs were cultured with E(2), 4-hydroxytamoxifen (OHT), and raloxifene.

MAIN OUTCOME MEASURE(S)

The VEGF and sVEGFR-1 messenger RNA (mRNA) levels in ESCs were determined using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Free (unbound) VEGF and sVEGFR-1 protein levels from ESCs were measured using ELISA kits.

RESULT(S)

The E(2) significantly induced VEGF mRNA levels, whereas E2 caused a significant decrease in sVEGFR-1 messenger RNA (mRNA) levels. The E(2) or OHT significantly increased the VEGF production levels and attenuated the sVEGFR-1 production compared with control, but raloxifene had no significant effect. The decrease in levels of free VEGF was proportional to the increase in sVEGFR-1 levels in the culture media of ESCs.

CONCLUSION(S)

The E(2) or OHT stimulates VEGF production and concurrently attenuates sVEGFR-1 production in ESCs. This consequential increase in VEGF:sVEGFR-1 ratio might enhance the biological effects of VEGF on the angiogenic environment in human endometrium.

Apratoxin a reversibly inhibits the secretory pathway by preventing cotranslational translocation

Apratoxin A is a potent cytotoxic marine natural product that rapidly inhibits signal transducer and activator of transcription (STAT) 3 phosphorylation by an undefined mechanism. We have used biochemical and proteomics approaches to illuminate upstream molecular events. Apratoxin A inhibits Janus kinase (JAK)/STAT signaling through rapid down-regulation of interleukin 6 signal transducer (gp130). Apratoxin A also depletes cancer cells of several cancer-associated receptor tyrosine kinases by preventing their N-glycosylation, leading to their rapid proteasomal degradation. A proteomics approach revealed that several proteins in the endoplasmic reticulum, the site of N-glycoprotein synthesis, are down-regulated upon apratoxin A exposure. Using in vitro cell free systems, we demonstrated that apratoxin A prevents cotranslational translocation of proteins destined for the secretory pathway. This process is reversible in living cells. Our study indicates that apratoxins are new tools to study the secretory pathway and raises the possibility that inhibition of cotranslational translocation may be exploited for anticancer drug development.

Estrous cycle modulates ovarian carcinoma growth

PURPOSE

The effects of reproductive hormones on ovarian cancer growth are not well understood. Here, we examined the effects of estrous cycle variation and specific reproductive hormones on ovarian cancer growth.

EXPERIMENTAL DESIGN

We investigated the role of reproductive hormones in ovarian cancer growth using both in vivo and in vitro models of tumor growth.

RESULTS

In vivo experiments using the HeyA8 and SKOV3ip1 ovarian cancer models showed that tumor cell inoculation during proestrus significantly increased tumor burden (251-273%) compared with injection during the estrus phase. Treatment of ovariectomized mice with 17beta-estradiol resulted in a 404% to 483% increase in tumor growth compared with controls. Progestins had no significant effect, but did block estrogen-stimulated tumor growth. Tumors collected from mice sacrificed during proestrus showed increased levels of vascular endothelial growth factor (VEGF) and microvessel density compared with mice injected during estrus. HeyA8, SKOV3ip1, and mouse endothelial (MOEC) cells expressed estrogen receptor alpha and beta and progesterone receptor at the protein and mRNA levels, whereas 2774 ovarian cancer cells were estrogen receptor-negative. In vitro assays showed that 17beta-estradiol significantly increased ovarian cancer cell adhesion to collagen in estrogen receptor-positive, but not in estrogen receptor-negative cells. Additionally, 17beta-estradiol increased the migratory potential of MOEC cells, which was abrogated by the mitogen-activated protein kinase (MAPK) inhibitor, PD 09859. Treatment with 17beta-estradiol activated MAPK in MOEC cells, but not in HeyA8 or SKOV3ip1 cells.

CONCLUSION

Our data suggest that estrogen may promote in vivo ovarian cancer growth, both directly and indirectly, by making the tumor microenvironment more conducive for cancer growth.

Estrogen-related receptor alpha induces the expression of vascular endothelial growth factor in breast cancer cells

Estrogen-related receptor alpha (ERRalpha) is an orphan member of the nuclear receptor family of transcription factors. In addition to its function as a metabolic regulator, ERRalpha has been implicated in the growth and progression of several malignancies. In the setting of breast cancer, not only is ERRalpha a putative negative prognostic factor, but we have recently found that knock-down of its expression retards tumor growth in a xenograft model of this disease. The specific aspects of ERRalpha function that are responsible for its actions in breast cancer, however, remain unclear. Using the coactivator PGC-1alpha as a protein ligand to regulate ERRalpha activity, we analyzed the effects of this receptor on gene expression in the ERalpha-positive MCF-7 cell line. This analysis led to the identification of a large number of potential ERRalpha target genes, many of which were subsequently validated in other breast cancer cell lines. Importantly, we demonstrate in this study that activation of ERRalpha in several different breast cancer cell lines leads to a significant increase in VEGF mRNA expression, an activity that translates into an increase in VEGF protein secretion. The induction of VEGF results from the interaction of ERRalpha with specific ERR-responsive elements within the VEGF promoter. These findings suggest that ERRalpha-dependent induction of VEGF may contribute to the overall negative phenotype observed in tumors in which ERRalpha is expressed and provide validation for its use as a therapeutic target in cancer.

Vascular endothelial growth factor, its soluble receptor, and hepatocyte growth factor: clinical and genetic correlates and association with vascular function

AIMS

Growth factors play an important role in regulating vascular function. Data are limited regarding clinical and genetic correlates of endothelial growth factors and their associations with vascular function.

METHODS AND RESULTS

We evaluated clinical and genetic correlates of circulating vascular endothelial growth factor A (VEGF), its soluble receptor sFlt-1, and hepatocyte growth factor (HGF) in 3754 Framingham Study participants. We also related the growth factors to measures of brachial artery function. Serum VEGF and HGF were higher and sFLt-1 was lower in women and smokers. VEGF and HGF were associated positively with body mass index; both displayed strong positive associations with the metabolic syndrome (P < 0.001) and its components. The heritabilities of VEGF, sFlt-1, and HGF were 78, 13, and 38%, respectively. VEGF and HGF were related positively to baseline brachial diameter (P < 0.01) and to baseline mean flow velocity (P < 0.001) in age- and sex-adjusted models, but the multivariable models failed to reach significance. None of the growth factors were related to flow-mediated dilation.

CONCLUSION

In our community-based sample, circulating VEGF and HGF demonstrated high heritabilities and a sexual dimorphism. Increased angiogenesis and greater endothelial cell turnover may underlie associations of these growth factors with risk factors including smoking.

Estradiol increases IL-8 secretion of normal human breast tissue and breast cancer in vivo

IL-8 or CXCL8 has been associated with tumor angiogenesis, metastasis, and poor prognosis in breast cancer. Estrogen is crucial in breast carcinogenesis and tumor progression. Whether sex steroids affect IL-8 secretion of normal breast tissue or breast cancer is not known. Several cell types in a tissue secrete IL-8. Hence, regulatory mechanisms of IL-8 need to be investigated in whole tissue. We used microdialysis to sample IL-8 in normal human breast tissue in situ in pre- and postmenopausal women, preoperatively in breast cancers of women, and in experimental breast cancer in mice. We found a significant positive correlation between IL-8 and estradiol in normal breast tissue and hormone-dependent breast cancer in vivo. Ex vivo, estradiol exposure increased the IL-8 secretion of normal whole breast tissue in culture. In experimental breast cancer, estradiol increased IL-8 whereas the anti-estrogen tamoxifen inhibited the secretion of IL-8 both in vitro and extracellularly in vivo in tumors of nude mice. An anti-IL-8 Ab inhibited endothelial cell proliferation induced by cancer cell produced IL-8 and tumors with low IL-8 levels exhibited decreased angiogenesis. Our results strongly suggest that estradiol has a critical role in the regulation of IL-8 in normal human breast tissue and human breast cancer. IL-8 may present a novel therapeutic target for estrogen driven breast carcinogenesis and tumor progression.

Vascular endothelial growth factor and breast cancer risk

Vascular endothelial growth factor (VEGF) is a key factor in angiogenesis and is important to carcinogenesis. Previous studies relating circulating levels of VEGF to breast cancer have been limited by small numbers of participants and lack of adjustment for confounders. We studied the association between serum VEGF and breast cancer in an unmatched case-control study of 407 pre- and postmenopausal women (n = 203 cases, n = 204 controls). Logistic regression was used to model the breast cancer risk as a function of natural log transformed VEGF levels adjusted for age, Gail score, education, physical activity, history of breastfeeding, serum testosterone, and hormone therapy (HT) use. The majority of the population was postmenopausal (67.6%) and the average age was 56 years; age and menopausal status were similar among cases and controls. Geometric mean VEGF levels were non-significantly higher in cases (321.4 pg/ml) than controls (291.4 pg/ml; p = 0.21). In a multivariable model, the odds of breast cancer was 37% higher for women with VEGF levels > or =314.2 pg/ml compared to those with levels below 314.2 pg/ml, albeit not significantly (p = 0.16). There was no interaction between VEGF and menopausal status (p = 0.52). In this case-control study, VEGF was not significantly associated with breast cancer risk in pre- and postmenopausal women.

Tamoxifen decreases extracellular TGF-beta1 secreted from breast cancer cells--a post-translational regulation involving matrix metalloproteinase activity

Transforming growth factor-beta1 (TGF-beta1) promotes cancer progression by regulating tumor cell growth and angiogenesis and high levels of TGF-beta1 have been associated with metastatic disease and poor prognosis in breast cancer patients. We have previously reported anti-angiogenic effects of the anti-estrogen tamoxifen in breast cancer, by increased matrix metalloproteinase-9 (MMP-9) activity and generation of endostatin. Here, we show that exposure of tamoxifen to ER-positive breast cancer cells for 7 days, decreased extracellular TGF-beta1. Intracellular TGF-beta1 levels were unaffected by tamoxifen treatment, indicating a post-translational regulation of TGF-beta1. Inhibition of MMP activity restored TGF-beta1 levels, suggesting an involvement of MMP activities in the down-regulation of TGF-beta1 by tamoxifen. Moreover, using an in vivo model of solid MCF-7 tumors in nude mice, we analyzed tumor levels of TGF-beta1 after in vivo treatment with estradiol and tamoxifen. Exposure of tumor-bearing mice to tamoxifen significantly decreased tumor TGF-beta1 protein levels, tumor growth and angiogenesis. In conclusion, our findings suggest a novel mechanism of action of tamoxifen in breast cancer via sex steroid dependent modulation of the proteolytic tumor microenvironment resulting in reduced extracellular TGF-beta1 levels.

Breast cancer proteomics reveals correlation between estrogen receptor status and differential phosphorylation of PGRMC1

Introduction

Breast tumors lacking the estrogen receptor-α (ER-α) have increased incidence of resistance to therapy and poorer clinical prognosis.

Methods

Whole tissue sections from 16 cryopreserved breast cancer tumors that were either positive or negative for the ER (eight ER positive and eight ER negative) were differentially analyzed by multiplex imaging of two-dimensional PAGE gels using 54 cm isoelectric focusing. Differentially detected spots of Progesterone Receptor Membrane Component 1 (PGRMC1) were shown to differ in phosphorylation status by differential two dimensional polyacrylamide gel electrophoresis of phosphatase-treated tumor proteins. Site directed mutagenesis was used to create putative phosphorylation site point mutants in PGRMC1. Stable transfectants of these mutants in MCF7 cells were assayed for their survival after oxidative stress, and for AKT kinase phosphorylation. Immune fluorescence using anti-PGRMC1 monoclonal antibody 5G7 was performed on breast cancer tissue microarrays.

Results

Proteins significantly differentially abundant between estrogen receptor negative and estrogen receptor positive tumors at the 0.1% level were consistent with published profiles, suggesting an altered keratin pool, and increased inflammation and wound responses in estrogen receptor negative tumors. Two of three spots of PGRMC1 were more abundant in estrogen receptor negative tumors. Phosphatase treatment of breast tumor proteins indicated that the PGRMC1 isoforms differed in their phosphorylation status. Simultaneous mutation of PGRMC1 serine-56 and serine-181 fully abrogated the sensitivity of stably transfected MCF7 breast cancer cells to peroxide-induced cell death. Immune fluorescence revealed that PGRMC1 was primarily expressed in ER-negative basal epithelial cells of mammary ductules. Even in advanced tumors, high levels of ER or PGRMC1 were almost mutually exclusive in individual cells. In five out of five examined ductal in situ breast cancers of comedo type, PGRMC1 was expressed in glucose transporter 1 negative or positive poorly oxygenated cells surrounding the necrotic core, surrounded by a more distal halo of ER-positive cells.

Conclusions

PGRMC1 phosphorylation may be involved in the clinical differences that underpin breast tumors of differing ER status.

The effects of neoadjuvant anastrozole and tamoxifen on circulating vascular endothelial growth factor and soluble vascular endothelial growth factor receptor 1 in breast cancer

PURPOSE

Vascular endothelial growth factor (VEGF) is a key angiogenic factor mediating neovascularization. Soluble VEGF receptor 1 (sVEGFR-1) is an intrinsic negative counterpart of VEGF signaling and the ratio of sVEGFR-1 to VEGF has been shown to be a prognostic factor. Estrogen-bound estrogen receptor enhances VEGF expression, providing a common link between these signaling pathways that may be targeted by endocrine therapy. We investigated the effects of anastrozole and tamoxifen over time on serum VEGF and sVEGFR-1.

EXPERIMENTAL DESIGN

The Immediate Preoperative Anastrozole, Tamoxifen, or Combined with Tamoxifen (IMPACT) trial compared the preoperative use of anastrozole with tamoxifen in postmenopausal women with estrogen receptor-positive primary operable breast cancer over 12 weeks. Circulating VEGF and sVEGFR-1 were measured by ELISA in 106 patients treated with anastrozole or tamoxifen alone at baseline and after 2 and 12 weeks of treatment.

RESULTS

The increase in serum VEGF from baseline to 12 weeks was significantly different between anastrozole and tamoxifen (anastrozole versus tamoxifen, 6% versus 38%; P = 0.047). There was a significant increase in sVEGFR-1 levels after 12 weeks of anastrozole (P = 0.037). The sVEGFR-1/VEGF ratio significantly decreased in the tamoxifen arm (P = 0.013) and the change in sVEGFR-1/VEGF ratio from baseline to 12 weeks was significantly different between anastrozole and tamoxifen (anastrozole versus tamoxifen, 24% increase versus 34% decrease; P = 0.013).

CONCLUSIONS

Treatment with anastrozole and tamoxifen resulted in differential effects on serum angiogenic markers. This may be related to the relative effectiveness of the treatments. These data provide further support for cross talk between estrogen receptor and VEGF.

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.