| 1. |
- Garvin, Stina, et al.
(författare)
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Effects of estradiol and tamoxifen on VEGF, soluble VEGFR-1, and VEGFR-2 in breast cancer and endothelial cells
- 2005
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Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 93:9, s. 1005-1010
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenesis is regulated by the balance between pro- and antiangiogenic factors. Vascular endothelial growth factor (VEGF), acting via the receptors VEGFR-1 and VEGFR-2, is a key mediator of tumour angiogenesis. The soluble form of the VEGF receptor-1 (sVEGFR-1) is an important negative regulator of VEGF-mediated angiogenesis. The majority of breast cancers are oestrogen dependent, but it is not fully understood how oestrogen and the antioestrogen, tamoxifen, affect the balance of angiogenic factors. Angiogenesis is a result of the interplay between cancer and endothelial cells, and sex steroids may exert effects on both cell types. In this study we show that oestradiol decreased secreted sVEGFR-1, increased secreted VEGF, and decreased the ratio of sVEGFR-1/VEGF in MCF-7 human breast cancer cells. The addition of tamoxifen opposed these effects. Moreover, human umbilical vein endothelial cells (HUVEC) incubated with supernatants from oestradiol-treated MCF-7 cells exhibited higher VEGFR-2 levels than controls. In vivo, MCF-7 tumours from oestradiol+tamoxifen-treated nude mice exhibited decreased tumour vasculature. Our results suggest that tamoxifen and oestradiol exert dual effects on the angiogenic environment in breast cancer by regulating cancer cell-secreted angiogenic ligands such as VEGF and sVEGFR-1 and by affecting VEGFR-2 expression of endothelial cells.
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| 2. |
- Garvin, Stina, et al.
(författare)
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Estradiol increases VEGF in human breast studied by whole-tissue culture.
- 2006
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Ingår i: Cell and Tissue Research. - : Springer Science and Business Media LLC. - 0302-766X .- 1432-0878. ; 325:2, s. 245-51
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Tidskriftsartikel (refereegranskat)abstract
- Sex steroid exposure constitutes a risk factor for breast cancer, but little is known about the effects of sex steroids on the normal breast, largely because of the lack of convenient models. We have developed a method of culturing normal breast tissue ex vivo. We have applied this method to investigate the effects of estradiol and progesterone on the key angiogenic mediator, vascular endothelial growth factor (VEGF), in the breast. Whole breast tissue was obtained from routine reduction mammoplasty. Tissue biopsies were cultured in vitro for 1-3 weeks, and the expression of luminal cytokeratin 18 was determined by immunohistochemistry. As an application, tissue biopsies were treated in vitro for 1 week with or without estradiol or estradiol and progesterone. Estrogen receptor, progesterone receptor, and Ki-67 were analyzed, and VEGF levels were examined by quantitative immunoassay and immunohistochemistry. Whole breast tissue was cultured ex vivo for 1 week with preserved morphology. Increased detachment of the luminal epithelium was observed after 2 weeks. Estradiol increased extracellular levels of VEGF in normal breast tissue biopsy medium. The addition of progesterone had neither stimulatory nor inhibitory effects on secreted VEGF. The method of whole breast tissue culturing thus provide a means by which to explore the biology of normal breast tissue. Our results suggest that estradiol exerts pro-angiogenic effects in normal breast by increasing levels of biologically active VEGF.
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| 3. |
- Garvin, Stina, et al.
(författare)
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Estradiol increases VEGF in normal human breast studied by whole-tissue culture
- 2006
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Ingår i: Cell Tissue Research. - : Springer Science and Business Media LLC. - 0302-766X .- 1432-0878. ; 325:2, s. 245-251
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Tidskriftsartikel (refereegranskat)abstract
- Sex steroid exposure constitutes a risk factor for breast cancer, but little is known about the effects of sex steroids on the normal breast, largely because of the lack of convenient models. We have developed a method of culturing normal breast tissue ex vivo. We have applied this method to investigate the effects of estradiol and progesterone on the key angiogenic mediator, vascular endothelial growth factor (VEGF), in the breast. Whole breast tissue was obtained from routine reduction mammoplasty. Tissue biopsies were cultured in vitro for 1–3 weeks, and the expression of luminal cytokeratin 18 was determined by immunohistochemistry. As an application, tissue biopsies were treated in vitro for 1 week with or without estradiol or estradiol and progesterone. Estrogen receptor, progesterone receptor, and Ki–67 were analyzed, and VEGF levels were examined by quantitative immunoassay and immunohistochemistry. Whole breast tissue was cultured ex vivo for 1 week with preserved morphology. Increased detachment of the luminal epithelium was observed after 2 weeks. Estradiol increased extracellular levels of VEGF in normal breast tissue biopsy medium. The addition of progesterone had neither stimulatory nor inhibitory effects on secreted VEGF. The method of whole breast tissue culturing thus provide a means by which to explore the biology of normal breast tissue. Our results suggest that estradiol exerts pro-angiogenic effects in normal breast by increasing levels of biologically active VEGF.
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| 4. |
- Nilsson, Ulrika, et al.
(författare)
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Angiogenin Regulation by Estradiol in Breast Tissue: Tamoxifen Inhibits Angiogenin Nuclear Translocation and Antiangiogenin Therapy Reduces Breast Cancer Growth In vivo
- 2010
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Ingår i: Clinical Cancer Research. - : American Association for Cancer Research, Inc.. - 1078-0432 .- 1557-3265. ; 16:14, s. 3659-3669
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
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| 6. |
- Nilsson, Ulrika, et al.
(författare)
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Tamoxifen and Flaxseed Alter Angiogenesis Regulators in Normal Human Breast Tissue In Vivo
- 2011
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 6:9
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Tidskriftsartikel (refereegranskat)abstract
- The incidence of breast cancer is increasing in the Western world and there is an urgent need for studies of the mechanisms of sex steroids in order to develop novel preventive strategies. Diet modifications may be among the means for breast cancer prevention. Angiogenesis, key in tumor progression, is regulated by the balance between pro-and anti-angiogenic factors, which are controlled in the extracellular space. Sampling of these molecules at their bioactive compartment is therefore needed. The aims of this study were to explore if tamoxifen, one of the most used anti-estrogen treatments for breast cancer affected some of the most important endogenous angiogenesis regulators, vascular endothelial growth factor (VEGF), angiogenin, and endostatin in normal breast tissue in vivo and if a diet supplementation with flaxseed had similar effects as tamoxifen in the breast. Microdialysis was used for in situ sampling of extracellular proteins in normal breast tissue of women before and after six weeks of tamoxifen treatment or before and after addition of 25 g/day of ground flaxseed to the diet or in control women. We show significant correlations between estradiol and levels of VEGF, angiogenin, and endostatin in vivo, which was verified in ex vivo breast tissue culture. Moreover, tamoxifen decreased the levels of VEGF and angiogenin in the breast whereas endostatin increased significantly. Flaxseed did not alter VEGF or angiogenin levels but similar to tamoxifen the levels of endostatin increased significantly. We conclude that one of the mechanisms of tamoxifen in normal breast tissue include tipping of the angiogenic balance into an anti-angiogenic state and that flaxseed has limited effects on the pro-angiogenic factors whereas the anti-angiogenic endostatin may be modified by diet. Further studies of diet modifications for breast cancer prevention are warranted.
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| 7. |
- Nilsson, Ulrika, et al.
(författare)
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Tamoxifen decreases extracellular TGF-beta 1 secreted from breast cancer cells - A post-translational regulation involving matrix metalloproteinase activity
- 2009
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 315:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor-beta 1 (TGF-beta 1) promotes cancer progression by regulating tumor cell growth and angiogenesis and high levels of TGF-beta 1 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-beta 1. Intracellular TGF-beta 1 levels were unaffected by tamoxifen treatment, indicating a post-translational regulation of TGF-beta 1. Inhibition of MMP activity restored TGF-beta 1 levels, suggesting an involvement of MMP activities in the down-regulation of TGF-beta 1 by tamoxifen. Moreover, using an in vivo model of solid MCF-7 tumors in nude mice, we analyzed tumor levels of TGF-beta 1 after in vivo treatment with estradiol and tamoxifen. Exposure of tumor-bearing mice to tamoxifen significantly decreased tumor TGF-beta 1 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-beta 1 levels.
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| 8. |
- Nilsson, Ulrika W., 1977-
(författare)
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Effects of sex steroids and tamoxifen on matrix metalloproteinase activity and generation of endostatin in the breast
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sex steroids are inevitable in women. However, long-term exposure to sex steroids increases the risk of breast cancer. A complete understanding of sex steroid control of the breast and how it relates to breast cancer risk is still lacking. Angiogenesis and proteolytic enzyme activity are crucial for the process by which tumors evolve into a vascularized, invasive phenotype. Matrix metalloproteinases are potent matrixdegrading enzymes that affect several steps in tumor progression including angiogenesis. In the female reproductive organs, sex steroids regulate angiogenesis and MMP activity, yet little is known how sex steroids affect these crucial events in normal and malignant breast tissue.This thesis elucidates a link between sex steroids, MMP activity, and angiogenesis. It is shown that estradiol down-regulates while tamoxifen up-regulates the protein expression and activity of MMP-2 and MMP-9 in human breast cancer cells in vitro and in human breast cancer xenografts in vivo. The results further suggest that a biological consequence of this regulation may be modulation of tumor angiogenesis. The net effect of adding tamoxifen to estradiol treatment was an increase in extracellular levels of the endogenous angiogenesis inhibitor endostatin and decreased levels of the tumor promoter TGF-β1 compared to estradiol treatment only. This was accompanied by reduced vasculature and decreased tumor growth. Similarly, a regulatory effect of estradiol and tamoxifen on endostatin generation was observed in normal human breast tissue by whole-tissue culture and microdialysis in human breast tissue in situ.In conclusion, the results presented in this thesis suggest previously unknown mechanisms of action of estradiol and tamoxifen in breast cancer and in normal human breast tissue, and novel means by which estradiol may tip the scale to favor angiogenesis. This knowledge may be important for the understanding of sex steroid dependent breast carcinogenesis and in the future development of tissue-specific preventive as well as therapeutic strategies against breast cancer.
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| 9. |
- Nilsson, Ulrika W., et al.
(författare)
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Estradiol and tamoxifen regulate endostatin generation via matrix metalloproteinase activity in breast cancer in vivo
- 2006
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 66:9, s. 4789-4794
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Tidskriftsartikel (refereegranskat)abstract
- Matrix metalloproteinases (MMP) are important regulators of tumor progression and angiogenesis. MMPs generate both proangiogenic and antiangiogenic fragments, such as vascular endothelial growth factor and endostatin. The in vivo activation of MMPs and endostatin generation occur mainly in the extracellular environment by interactions of different cell types. Therefore, these processes are necessary to study in the extracellular space in vivo. Sex steroids play a dominant role in breast carcinogenesis, by largely unknown mechanisms. In the present study, we used in vivo microdialysis to directly quantify MMP-2 and MMP-9 activity and sample endostatin from both stroma (murine) and tumor (human) cells in vivo in solid MCF-7 tumors in nude mice. We found that tamoxifen in combination with estradiol increased tumor MMP-2/MMP-9 in vivo activity, endostatin levels, and decreased tumor vascularization compared with estradiol treatment only. The stroma-derived endostatin was three to five times higher than cancer cell–generated endostatin. After inhibition of MMP-2/MMP-9, endostatin levels decreased, providing evidence that these proteases are highly involved in the generation of endostatin. Our results support the previously reported concept that MMPs may serve as negative regulators of angiogenesis. The regulation of endostatin generation by modulation of MMP-2/MMP-9 activities suggests a previously unrecognized mechanism of estradiol and tamoxifen, which may have implications for the pathogenesis of breast cancer.
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| 10. |
- Nilsson, Ulrika W., et al.
(författare)
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MMP‐2 and MMP‐9 activity is regulated by estradiol and tamoxifen in cultured human breast cancer cells
- 2007
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Ingår i: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 0167-6806 .- 1573-7217. ; 102:3, s. 253-261
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Tidskriftsartikel (refereegranskat)abstract
- Sex steroids play a dominant role in breast carcinogenesis by still largely unknown mechanisms. Matrix metalloproteinases (MMPs) have been extensively studied in the context of matrix biology but it is not known if sex steroids affect MMPs in breast cancer. MMPs degrade extracellular matrix components enabling tumor cell invasion and metastasis, but may also regulate the bioavailability of a variety of biologically active molecules such as anti-angiogenic fragments, which may be beneficial for the host. This study shows that estradiol and tamoxifen regulate MMP-2 and MMP-9 as well as TIMP-1 and TIMP-2 in ER + PR + human breast cancer cells. The main finding was a significant effect of tamoxifen exposure, which increased intracellular and secreted protein levels whereas estradiol induced a significant decrease. The overall net effect of these alterations resulted in increased MMP-2/MMP-9 activity by tamoxifen treatment, which also significantly increased extracellular endostatin levels. We conclude that estradiol and tamoxifen have the ability to modulate MMP-2/MMP-9 activity, and endostatin levels in human breast cancer in vitro. The results suggest a possible role of MMP modulation associated with a generation of anti-angiogenic fragments in the therapeutic effect of tamoxifen in breast cancer.
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