3,4-Difluorobenzocurcumin Inhibits Vegfc-Vegfr3-Erk Signalling to Block Developmental Lymphangiogenesis in Zebrafish.
ABSTRACT: Lymphangiogenesis, the formation of new lymphatic vessels from pre-existing vasculature, plays critical roles in disease, including in cancer metastasis and chronic inflammation. Preclinical and recent clinical studies have now demonstrated therapeutic utility for several anti-lymphangiogenic agents, but optimal agents and efficacy in different settings remain to be determined. We tested the anti-lymphangiogenic property of 3,4-Difluorobenzocurcumin (CDF), which has previously been implicated as an anti-cancer agent, using zebrafish embryos and cultured vascular endothelial cells. We used transgenic zebrafish labelling the lymphatic system and found that CDF potently inhibits lymphangiogenesis during embryonic development. We also found that the parent compound, Curcumin, does not inhibit lymphangiogenesis. CDF blocked lymphatic and venous sprouting, and lymphatic migration in the head and trunk of the embryo. Mechanistically, CDF impaired VEGFC-VEGFR3-ERK signalling in vitro and in vivo. In an in vivo pathological model of Vegfc-overexpression, treatment with CDF rescued endothelial cell hyperplasia. CDF did not inhibit the kinase activity of VEGFR3 yet displayed more prolonged activity in vivo than previously reported kinase inhibitors. These findings warrant further assessment of CDF and its mode of action as a candidate for use in metastasis and diseases of aberrant lymphangiogenesis.
Project description:Angiogenesis and lymphangiogenesis are key processes during embryogenesis as well as under physiological and pathological conditions. Vascular endothelial growth factor C (VEGFC), the ligand for both VEGFR2 and VEGFR3, is a central lymphangiogenic regulator that also drives angiogenesis. Here, we report that members of the highly conserved BACH (BTB and CNC homology) family of transcription factors regulate VEGFC expression, through direct binding to its promoter. Accordingly, down-regulation of bach2a hinders blood vessel formation and impairs lymphatic sprouting in a Vegfc-dependent manner during zebrafish embryonic development. In contrast, BACH1 overexpression enhances intratumoral blood vessel density and peritumoral lymphatic vessel diameter in ovarian and lung mouse tumor models. The effects on the vascular compartment correlate spatially and temporally with BACH1 transcriptional regulation of VEGFC expression. Altogether, our results uncover a novel role for the BACH/VEGFC signaling axis in lymphatic formation during embryogenesis and cancer, providing a novel potential target for therapeutic interventions.
Project description:The molecular mechanisms initiating the formation of the lymphatic system, lymphangiogenesis, are still poorly understood. Here we have identified a novel role in lymphangiogenesis for an ETS transcription factor, Etv2/Etsrp, a known regulator of embryonic vascular development. Through the use of fully validated photoactivatable morpholinos we show that inducible Etv2 inhibition in zebrafish embryos at 1?day post-fertilization (dpf) results in significant inhibition of lymphangiogenesis, while development of blood vessels is unaffected. In Etv2-inhibited embryos and larvae, the number of lymphatic progenitors is greatly reduced, the major lymphatic vessel, the thoracic duct, is absent or severely fragmented, and lymphangiogenesis-associated marker expression, including lyve1b, prox1a, and vegfr3/flt4, is strongly downregulated. We also demonstrate that lymphatic progenitors in Etv2 deficient embryos fail to respond to Vegfc signaling. Chromatin immunoprecipitation and sequencing (ChIP-Seq) studies using differentiated mouse embryonic stem (ES) cells as well as luciferase reporter studies in the ES cells and in zebrafish embryos argue that Etv2 directly binds the promoter/enhancer regions of Vegfc receptor Vegfr3/Flt4 and lymphatic marker Lyve1, and promotes their expression. Together these data support a model where Etv2 initiates lymphangiogenesis by directly promoting the expression of flt4 within the posterior cardinal vein.
Project description:Lymphangiogenesis is supported by 2 homologous VEGFR3 ligands, VEGFC and VEGFD. VEGFC is required for lymphatic development, while VEGFD is not. VEGFC and VEGFD are proteolytically cleaved after cell secretion in vitro, and recent studies have implicated the protease a disintegrin and metalloproteinase with thrombospondin motifs 3 (ADAMTS3) and the secreted factor collagen and calcium binding EGF domains 1 (CCBE1) in this process. It is not well understood how ligand proteolysis is controlled at the molecular level or how this process regulates lymphangiogenesis, because these complex molecular interactions have been difficult to follow ex vivo and test in vivo. Here, we have developed and used biochemical and cellular tools to demonstrate that an ADAMTS3-CCBE1 complex can form independently of VEGFR3 and is required to convert VEGFC, but not VEGFD, into an active ligand. Consistent with these ex vivo findings, mouse genetic studies revealed that ADAMTS3 is required for lymphatic development in a manner that is identical to the requirement of VEGFC and CCBE1 for lymphatic development. Moreover, CCBE1 was required for in vivo lymphangiogenesis stimulated by VEGFC but not VEGFD. Together, these studies reveal that lymphangiogenesis is regulated by two distinct proteolytic mechanisms of ligand activation: one in which VEGFC activation by ADAMTS3 and CCBE1 spatially and temporally patterns developing lymphatics, and one in which VEGFD activation by a distinct proteolytic mechanism may be stimulated during inflammatory lymphatic growth.
Project description:Here, we show that a novel Rspo1-Wnt-Vegfc-Vegfr3 signaling pathway plays an essential role in developmental angiogenesis. A mutation in R-spondin1 (rspo1), a Wnt signaling regulator, was uncovered during a forward-genetic screen for angiogenesis-deficient mutants in the zebrafish. Embryos lacking rspo1 or the proposed rspo1 receptor kremen form primary vessels by vasculogenesis, but are defective in subsequent angiogenesis. Endothelial cell-autonomous inhibition of canonical Wnt signaling also blocks angiogenesis in vivo. The pro-angiogenic effects of Rspo1/Wnt signaling are mediated by Vegfc/Vegfr3(Flt4) signaling. Vegfc expression is dependent on Rspo1 and Wnt, and Vegfc and Vegfr3 are necessary to promote angiogenesis downstream from Rspo1-Wnt. As all of these molecules are expressed by the endothelium during sprouting stages, these results suggest that Rspo1-Wnt-VegfC-Vegfr3 signaling plays a crucial role as an endothelial-autonomous permissive cue for developmental angiogenesis.
Project description:The lymphatic vasculature plays roles in tissue fluid balance, immune cell trafficking, fatty acid absorption, cancer metastasis, and cardiovascular disease. Lymphatic vessels form by lymphangiogenesis, the sprouting of new lymphatics from pre-existing vessels, in both development and disease contexts. The apical signaling pathway in lymphangiogenesis is the VEGFC/VEGFR3 pathway, yet how signaling controls cellular transcriptional output remains unknown. We used a forward genetic screen in zebrafish to identify the transcription factor mafba as essential for lymphatic vessel development. We found that mafba is required for the migration of lymphatic precursors after their initial sprouting from the posterior cardinal vein. mafba expression is enriched in sprouts emerging from veins, and we show that mafba functions cell-autonomously during lymphatic vessel development. Mechanistically, Vegfc signaling increases mafba expression to control downstream transcription, and this regulatory relationship is dependent on the activity of SoxF transcription factors, which are essential for mafba expression in venous endothelium. Here we identify an indispensable Vegfc-SoxF-Mafba pathway in lymphatic development.
Project description:Colorectal cancer (CRC) is one of the major causes of cancer-related death in Western countries and is associated with increased numbers of lymphatic vessels (LVs) and tumor-associated macrophages (TAMs). The VEGFC/VEGFR3 pathway is regarded as the principal inducer of lymphangiogenesis and it contributes to metastases; however, no data are available on its role during CRC development. We found that both VEGFC and VEGFR3 were upregulated in human non-metastatic CRC, with VEGFR3 localising on both LVs and TAMs. We further proved in different preclinical models of CRC, that VEGFC/VEGFR3 axis can shape both LECs and TAMs to synergically inhibit anti-tumor immunity and promote primary CRC growth. VEGFR3-directed therapy could be envisioned for the treatment of non-metastatic CRC. Overall design: n=8 Lymphatic cell samples and n=8 Macrophage samples with or without anti-VEGFR3 treatment.
Project description:The lymphatic vasculature mediates essential physiological functions including fluid homeostasis, lipid and hormone transport, and immune cell trafficking. Recent studies have suggested that promoting lymphangiogenesis enhances cardiac repair following injury, but it is unknown whether lymphangiogenesis is required for cardiac regeneration. Here, we describe the anatomical distribution, regulation, and function of the cardiac lymphatic network in a highly regenerative zebrafish model system using transgenic reporter lines and loss-of-function approaches. We show that zebrafish lacking functional <i>vegfc</i> and <i>vegfd</i> signaling are devoid of a cardiac lymphatic network and display cardiac hypertrophy in the absence of injury, suggesting a role for these vessels in cardiac tissue homeostasis. Using two different cardiac injury models, we report a robust lymphangiogenic response following cryoinjury, but not following apical resection injury. Although the majority of mutants lacking functional <i>vegfc</i> and <i>vegfd</i> signaling were able to mount a full regenerative response even in the complete absence of a cardiac lymphatic vasculature, cardiac regeneration was severely impaired in a subset of mutants, which was associated with heightened pro-inflammatory cytokine signaling. These findings reveal a context-dependent requirement for the lymphatic vasculature during cardiac growth and regeneration.
Project description:Hemostasis associated with tissue injury is followed by wound healing, a complex process by which damaged cellular material is removed and tissue repaired. Angiogenic responses are a central aspect of wound healing, including the growth of new lymphatic vessels by which immune cells, protein, and fluid are transported out of the wound area. The concept that hemostatic responses might be linked to wound healing responses is an old one, but demonstrating such a link in vivo and defining specific molecular mechanisms by which the 2 processes are connected has been difficult. In the present study, we demonstrate that the lymphangiogenic factors vascular endothelial growth factor C (VEGFC) and VEGFD are cleaved by thrombin and plasmin, serine proteases generated during hemostasis and wound healing. Using a new tail-wounding assay to test the relationship between clot formation and lymphangiogenesis in mice, we find that platelets accelerate lymphatic growth after injury in vivo. Genetic studies reveal that platelet enhancement of lymphatic growth after wounding is dependent on the release of VEGFC, but not VEGFD, a finding consistent with high expression of VEGFC in both platelets and avian thrombocytes. Analysis of lymphangiogenesis after full-thickness skin excision, a wound model that is not associated with significant clot formation, also revealed an essential role for VEGFC, but not VEGFD. These studies define a concrete molecular and cellular link between hemostasis and lymphangiogenesis during wound healing and reveal that VEGFC, the dominant lymphangiogenic factor during embryonic development, continues to play a dominant role in lymphatic growth in mature animals.
Project description:BACKGROUND:Infiltration into lymphatic vessels is a critical step in breast cancer metastasis. Lymphatics undergo changes that facilitate metastasis as a result of activation of the cells lining lymphatic vessels, lymphatic endothelial cells (LECs). Inhibition of activation by targeting VEGFR3 can reduce invasion toward lymphatics. To best benefit patients, this approach should be coupled with standard of care that slows tumor growth, such as chemotherapy. Little is known about how chemotherapies, like docetaxel, may influence lymphatics and conversely, how lymphatics can alter responses to therapy. METHODS:A novel 3D in vitro co-culture model of the human breast tumor microenvironment was employed to examine the contribution of LECs to tumor invasion and viability with docetaxel and anti-VEGFR3, using three cell lines, MDA-MB-231, HCC38, and HCC1806. In vivo, the 4T1 mouse model of breast carcinoma was used to examine the efficacy of combinatorial therapy with docetaxel and anti-VEGFR3 on lymph node metastasis and tumor growth. Lymphangiogenesis in these mice was analyzed by immunohistochemistry and flow cytometry. Luminex analysis was used to measure expression of lymphangiogenic cytokines. RESULTS:In vitro, tumor cell invasion significantly increased with docetaxel when LECs were present; this effect was attenuated by inhibition of VEGFR3. LECs reduced docetaxel-induced cell death independent of VEGFR3. In vivo, docetaxel significantly increased breast cancer metastasis to the lymph node. Docetaxel and anti-VEGFR3 combination therapy reduced lymph node and lung metastasis in 4T1 and synergized to reduce tumor growth. Docetaxel induced VEGFR3-dependent vessel enlargement, lymphangiogenesis, and expansion of the LEC population in the peritumoral microenvironment, but not tumor-free stroma. Docetaxel caused an upregulation in pro-lymphangiogenic factors including VEGFC and TNF-? in the tumor microenvironment in vivo. CONCLUSIONS:Here we present a counter-therapeutic effect of docetaxel chemotherapy that triggers cancer cells to elicit lymphangiogenesis. In turn, lymphatics reduce cancer response to docetaxel by altering the cytokine milieu in breast cancer. These changes lead to an increase in tumor cell invasion and survival under docetaxel treatment, ultimately reducing docetaxel efficacy. These docetaxel-induced effects can be mitigated by anti-VEGFR3 therapy, resulting in a synergism between these treatments that reduces tumor growth and metastasis.
Project description:Lymphatic vascular development involves specification of lymphatic endothelial progenitors that subsequently undergo sprouting, proliferation and tissue growth to form a complex second vasculature. The Hippo pathway and effectors Yap and Taz control organ growth and regulate morphogenesis and cellular proliferation. Yap and Taz control angiogenesis but a role in lymphangiogenesis remains to be fully elucidated. Here we show that YAP displays dynamic changes in lymphatic progenitors and Yap1 is essential for lymphatic vascular development in zebrafish. Maternal and Zygotic (MZ) yap1 mutants show normal specification of lymphatic progenitors, abnormal cellular sprouting and reduced numbers of lymphatic progenitors emerging from the cardinal vein during lymphangiogenesis. Furthermore, Yap1 is indispensable for Vegfc-induced proliferation in a transgenic model of Vegfc overexpression. Paracrine Vegfc-signalling ultimately increases nuclear YAP in lymphatic progenitors to control lymphatic development. We thus identify a role for Yap in lymphangiogenesis, acting downstream of Vegfc to promote expansion of this vascular lineage.