| 1. |
- Cao, Ziquan, 1982-
(författare)
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VEGF-mediated vascular functions in health and disease
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Angiogenesis is essential for physiological processes including embryonic development, tissue regeneration, and reproduction. Under various pathological conditions the same angiogenic process contribute to the onset, development, and progression of many human diseases including cancer, diabetic complications, ocular disease, chronic inflammation and cardiovascular disease. Vascular endothelial growth factor (VEGF) is a key angiogenic factor for physiological and pathological angiogenesis. In addition to its strong angiogenic activity, VEGF also potently induces vascular permeability, often causing tissue edema in various pathological tissues. VEGF transduces its vascular signal through two tyrosine kinase receptors-VEGFR1 and VEGFR2, the latter being a functional receptor that mediates both angiogenic and vascular permeability effects. To study physiological and pathological functions of VEGF, we developed novel zebrafish disease models that permit us to study hypoxia-induced retinopathy and cancer metastasis processes. We have also administered anti-VEGF and anti-VEGFR specific antibodies to healthy mice to study the homeostatic role of VEGF in the maintenance of vascular integrity and its functions in various tissues and organs.Finally, using a zebrafish model, we evaluated if VEGF expression is regulated by circadian clock genes. In paper I, we developed protocols that create hypoxia-induced retinopathy in adult zebrafish. Adult fli1:EGFP zebrafish were placed in hypoxic water for 3-10 days with retinal neovascularization being analyzed using confocal microscopy. This model provides a unique opportunity to kinetically study the development of retinopathy in adult animals using non-invasive protocols and to assess the therapeutic efficacy of orally administered anti-angiogenic drugs. In paper II, we developed a zebrafish metastasis model to dissect the complex events of hypoxia-induced tumor cell invasion and metastasis in association with angiogenesis at the single-cell level. In this model, fluorescent DiI-labeled human or mouse tumor cells were implanted into the perivitelline cavity of 48-hour-old zebrafish embryos, which were subsequently placed in hypoxic water for 3 days. Tumor cell invasion, metastasis and pathological angiogenesis were analyzed using fluorescent microscopy in the living fish. The average experimental time for this model is 7 days. Our protocol offers an opportunity to study molecular mechanisms of hypoxia-induced cancer metastasis. In paper III, we show that systemic delivery of an anti-VEGF or an anti-VEGF receptor (VEGFR)-2 neutralizing antibody cause global vascular regression in mice. Among all examined tissues, the vasculature in endocrine glands, intestinal villi, and the uterus are most affected in response to VEGF or VEGFR-2 blockades. Pro-longed anti-VEGF treatment resulted in a significant decrease in the circulating levels of the predominant thyroid hormone, free thyroxine, but not the minimal isoform of triiodothyronine, suggesting that chronic anti-VEGF treatment impairs thyroid function. These findings provide structural and functional bases of anti-VEGF-specific druginduced side effects in relation to vascular changes in healthy tissues. In paper IV, we show that disruption of the circadian clock by constant exposure to light coupled with genetic manipulation of key genes in the zebrafish led to impaired developmental angiogenesis. A bmal1-specific morpholino inhibited developmental angiogenesis in zebrafish embryos without causing obvious nonvascular phenotypes. Conversely, a period2 morpholino accelerated angiogenic vessel growth, suggesting that Bmal1 and Period2 display opposing angiogenic effects. These results offer mechanistic insights into the role of the circadian clock in regulation of developmental angiogenesis, and our findings may be reasonably extended to other types of physiological or pathological angiogenesis. Overall, the results in this thesis provide further insight to angiogenic mechanistic properties in tissues and suggest possible novel therapeutic targets for the treatment of various angiogenesis-dependent diseases.
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| 2. |
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| 3. |
- Chen, Xiaoyun, et al.
(författare)
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Invasiveness and metastasis of retinoblastoma in an orthotopic zebrafish tumor model
- 2015
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Ingår i: Scientific Reports. - : Nature Publishing Group: Open Access Journals - Option C / Nature Publishing Group. - 2045-2322. ; 5:10351
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Tidskriftsartikel (refereegranskat)abstract
- Retinoblastoma is a highly invasive malignant tumor that often invades the brain and metastasizes to distal organs through the blood stream. Invasiveness and metastasis of retinoblastoma can occur at the early stage of tumor development. However, an optimal preclinical model to study retinoblastoma invasiveness and metastasis in relation to drug treatment has not been developed. Here, we developed an orthotopic zebrafish model in which retinoblastoma invasion and metastasis can be monitored at a single cell level. We took the advantages of immune privilege and transparent nature of developing zebrafish embryos. Intravitreal implantation of color-coded retinoblastoma cells allowed us to kinetically monitor tumor cell invasion and metastasis. Further, interactions between retinoblastoma cells and surrounding microvasculatures were studied using a transgenic zebrafish that exhibited green fluorescent signals in blood vessels. We discovered that tumor cells invaded neighboring tissues and blood stream when primary tumors were at the microscopic sizes. These findings demonstrate that retinoblastoma metastasis occurs at the early stage and antiangiogenic drugs such as Vegf morpholino and sunitinib could potentially interfere with tumor invasiveness and metastasis. Thus, this orthotopic retinoblastoma model offers a new and unique opportunity to study the early events of tumor invasion, metastasis and drug responses.
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| 4. |
- Ji, Hong, et al.
(författare)
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TNFR1 mediates TNF-alpha-induced tumour lymphangiogenesis and metastasis by modulating VEGF-C-VEGFR3 signalling
- 2014
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Ingår i: Nature Communications. - : Nature Publishing Group: Nature Communications. - 2041-1723. ; 5:4944
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Tidskriftsartikel (refereegranskat)abstract
- Inflammation and lymphangiogenesis are two cohesively coupled processes that promote tumour growth and invasion. Here we report that TNF-alpha markedly promotes tumour lymphangiogenesis and lymphatic metastasis. The TNF-alpha-TNFR1 signalling pathway directly stimulates lymphatic endothelial cell activity through a VEGFR3-independent mechanism. However, VEGFR3-induced lymphatic endothelial cell tips are a prerequisite for lymphatic vessel growth in vivo, and a VEGFR3 blockade completely ablates TNF-alpha-induced lymphangiogenesis. Moreover, TNF-alpha-TNFR1-activated inflammatory macrophages produce high levels of VEGF-C to coordinately activate VEGFR3. Genetic deletion of TNFR1 (Tnfr1(-/-)) in mice or depletion of tumour-associated macrophages (TAMs) virtually eliminates TNF-alpha-induced lymphangiogenesis and lymphatic metastasis. Gain-of-function experiments show that reconstitution of Tnfr1(+/+) macrophages in Tnfr1(+/+) mice largely restores tumour lymphangiogenesis and lymphatic metastasis. These findings shed mechanistic light on the intimate interplay between inflammation and lymphangiogenesis in cancer metastasis, and propose therapeutic intervention of lymphatic metastasis by targeting the TNF-alpha-TNFR1 pathway.
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| 5. |
- Kubo, Hajime, et al.
(författare)
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Blockade of vascular endothelial growth factor receptor-3 signaling inhibits fibroblast growth factor-2-induced lymphangiogenesis in mouse cornea.
- 2002
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 99:13
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor receptor-3 (VEGFR-3) is a major mediator of lymphangiogenesis. Recently, VEGFR-3 ligands, VEGF-C, and VEGF-D were reported to promote tumor lymphangiogenesis and lymphatic metastasis, and these processes were inhibited by blocking of the VEGFR-3-signaling pathway. Here, we have adapted the mouse corneal angiogenesis assay to study potential lymphangiogenic factors and inhibitors. Immunohistochemical analysis with lymphatic endothelial markers showed that VEGF-C induces lymphatic as well as blood vessel growth in the cornea. By contrast, VEGF induced angiogenesis but not lymphangiogenesis. Fibroblast growth factor-2 (FGF-2) stimulated both lymphangiogenesis and angiogenesis. FGF-2 up-regulated VEGF-C expression in vascular endothelial and perivascular cells. Furthermore, administration of blocking anti-VEGFR-3 antibodies inhibited the FGF-2-induced lymphangiogenesis. These findings show that VEGFR-3 can mediate lymphangiogenesis induced by other growth factors. Because increased expression of FGF-2 and VEGF-C has been associated with lymphatic metastasis, our results provide a potential strategy for the inhibition of lymphatic metastasis in cancer therapy.
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| 6. |
- Wang, Jian, et al.
(författare)
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Novel Mechanism of Macrophage-Mediated Metastasis Revealed in a Zebrafish Model of Tumor Development
- 2015
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Ingår i: Cancer Research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 75:2, s. 306-315
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Tidskriftsartikel (refereegranskat)abstract
- Cancer metastasis can occur at early stages of tumor development due to facilitative alterations in the tumor microenvironment. Although imaging techniques have considerably improved our understanding of metastasis, early events remain challenging to study due to the small numbers of malignant cells involved that are often undetectable. Using a novel zebrafish model to investigate this process, we discovered that tumor-associated macrophages (TAM) acted to facilitate metastasis by binding tumor cells and mediating their intravasation. Mechanistic investigations revealed that IL6 and TNF alpha promoted the ability of macrophages to mediate this step. M2 macro-phages were particularly potent when induced by IL4, IL10, and TGF beta. In contrast, IFN gamma-lipopolysaccharide-induced M1 macrophages lacked the capability to function in the same way in the model. Confirming these observations, we found that human TAM isolated from primary breast, lung, colorectal, and endometrial cancers exhibited a similar capability in invasion and metastasis. Taken together, our work shows how zebrafish can be used to study how host contributions can facilitate metastasis at its earliest stages, and they reveal a new macrophage-dependent mechanism of metastasis with possible prognostic implications.
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| 7. |
- Yang, Xiaojuan, et al.
(författare)
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VEGF-B promotes cancer metastasis through a VEGF-A-independent mechanism and serves as a marker of poor prognosis for cancer patients
- 2015
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:22, s. E2900-E2909
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Tidskriftsartikel (refereegranskat)abstract
- The biological functions of VEGF-B in cancer progression remain poorly understood. Here, we report that VEGF-B promotes cancer metastasis through the remodeling of tumor microvasculature. Knockdown of VEGF-B in tumors resulted in increased perivascular cell coverage and impaired pulmonary metastasis of human melanomas. In contrast, the gain of VEGF-B function in tumors led to pseudonormalized tumor vasculatures that were highly leaky and poorly perfused. Tumors expressing high levels of VEGF-B were more metastatic, although primary tumor growth was largely impaired. Similarly, VEGF-B in a VEGF-A-null tumor resulted in attenuated primary tumor growth but substantial pulmonary metastases. VEGF-B also led to highly metastatic phenotypes in Vegfr1 tk(-/-) mice and mice treated with anti-VEGF-A. These data indicate that VEGF-B promotes cancer metastasis through a VEGF-A-independent mechanism. High expression levels of VEGF-B in two large-cohort studies of human patients with lung squamous cell carcinoma and melanoma correlated with poor survival. Taken together, our findings demonstrate that VEGF-B is a vascular remodeling factor promoting cancer metastasis and that targeting VEGF-B may be an important therapeutic approach for cancer metastasis.
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| 8. |
- Yang, Yunlong, et al.
(författare)
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The PDGF-BB-SOX7 axis-modulated IL-33 in pericytes and stromal cells promotes metastasis through tumour-associated macrophages
- 2016
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 7:11385
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Tidskriftsartikel (refereegranskat)abstract
- Signalling molecules and pathways that mediate crosstalk between various tumour cellular compartments in cancer metastasis remain largely unknown. We report a mechanism of the interaction between perivascular cells and tumour-associated macrophages (TAMs) in promoting metastasis through the IL-33-ST2-dependent pathway in xenograft mouse models of cancer. IL-33 is the highest upregulated gene through activation of SOX7 transcription factor in PDGF-BB-stimulated pericytes. Gain-and loss-of-function experiments validate that IL-33 promotes metastasis through recruitment of TAMs. Pharmacological inhibition of the IL-33-ST2 signalling by a soluble ST2 significantly inhibits TAMs and metastasis. Genetic deletion of host IL-33 in mice also blocks PDGF-BB-induced TAM recruitment and metastasis. These findings shed light on the role of tumour stroma in promoting metastasis and have therapeutic implications for cancer therapy.
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| 9. |
- Ali, Zaheer, et al.
(författare)
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Intussusceptive Vascular Remodeling Precedes Pathological Neovascularization
- 2019
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - : Lippincott Williams & Wilkins. - 1079-5642 .- 1524-4636. ; 39:7, s. 1402-1418
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Tidskriftsartikel (refereegranskat)abstract
- Objective—Pathological neovascularization is crucial for progression and morbidity of serious diseases such as cancer, diabetic retinopathy, and age-related macular degeneration. While mechanisms of ongoing pathological neovascularization have been extensively studied, the initiating pathological vascular remodeling (PVR) events, which precede neovascularization remains poorly understood. Here, we identify novel molecular and cellular mechanisms of preneovascular PVR, by using the adult choriocapillaris as a model.Approach and Results—Using hypoxia or forced overexpression of VEGF (vascular endothelial growth factor) in the subretinal space to induce PVR in zebrafish and rats respectively, and by analyzing choriocapillaris membranes adjacent to choroidal neovascular lesions from age-related macular degeneration patients, we show that the choriocapillaris undergo robust induction of vascular intussusception and permeability at preneovascular stages of PVR. This PVR response included endothelial cell proliferation, formation of endothelial luminal processes, extensive vesiculation and thickening of the endothelium, degradation of collagen fibers, and splitting of existing extravascular columns. RNA-sequencing established a role for endothelial tight junction disruption, cytoskeletal remodeling, vesicle- and cilium biogenesis in this process. Mechanistically, using genetic gain- and loss-of-function zebrafish models and analysis of primary human choriocapillaris endothelial cells, we determined that HIF (hypoxia-induced factor)-1α-VEGF-A-VEGFR2 signaling was important for hypoxia-induced PVR.Conclusions—Our findings reveal that PVR involving intussusception and splitting of extravascular columns, endothelial proliferation, vesiculation, fenestration, and thickening is induced before neovascularization, suggesting that identifying and targeting these processes may prevent development of advanced neovascular disease in the future.Visual Overview—An online visual overview is available for this article.
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| 10. |
- Bandaru, Sashidar, et al.
(författare)
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Targeting filamin B induces tumor growth and metastasis via enhanced activity of matrix metalloproteinase-9 and secretion of VEGF-A : Role of filamin in tumor growth.
- 2014
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Ingår i: Oncogenesis. - : Springer Science and Business Media LLC. - 2157-9024. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Filamins regulate cell locomotion and associate with diverse signaling molecules. We have recently found that targeting filamin A (FLNA) reduces RAS-induced lung adenocarcinomas. In this study, we explored the role of another major filamin isoform, filamin B (FLNB), in tumor development. In contrast to FLNA, we report that targeting FLNB enhances RAS-induced tumor growth and metastasis which is associated with higher matrix metallopeptidase-9 (MMP-9) and extracellular signal-regulated kinase (ERK) activity. Flnb deficiency in mouse embryonic fibroblasts results in increased proteolytic activity of MMP-9 and cell invasion mediated by the RAS/ERK pathway. Similarly, silencing FLNB in multiple human cancer cells increases the proteolytic activity of MMP-9 and tumor cell invasion. Furthermore, we observed that Flnb-deficient RAS-induced tumors display more capillary structures that is correlated with increased vascular endothelial growth factor-A (VEGF-A) secretion. Inhibition of ERK activation blocks phorbol myristate acetate-induced MMP-9 activity and VEGF-A secretion in vitro. In addition, silencing FLNB in human ovarian cancer cells increases secretion of VEGF-A that induces endothelial cells to form more vascular structures in vitro. We conclude that FLNB suppresses tumor growth and metastasis by regulating the activity of MMP-9 and secretion of VEGF-A which is mediated by the RAS/ERK pathway.
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