ABSTRACT
Mutations in SOX18, VEGFC and Vascular Endothelial Growth Factor 3 underlie the hereditary lymphatic disorders hypotrichosis-lymphedema-telangiectasia (HLT), Milroy-like lymphedema and Milroy disease, respectively. Genes responsible for hereditary lymphedema are key regulators of lymphatic vascular development in the embryo. To identify novel modulators of lymphangiogenesis, we used a mouse model of HLT (Ragged Opossum) and performed gene expression profiling of aberrant dermal lymphatic vessels. Expression studies and functional analysis in zebrafish and mice revealed one candidate, ArfGAP with RhoGAP domain, Ankyrin repeat and PH domain 3 (ARAP3), which is down-regulated in HLT mouse lymphatic vessels and necessary for lymphatic vascular development in mice and zebrafish. We position this known regulator of cell behaviour during migration as a mediator of the cellular response to Vegfc signalling in lymphatic endothelial cells in vitro and in vivo. Our data refine common mechanisms that are likely to contribute during both development and the pathogenesis of lymphatic vascular disorders.
Subject(s)
Adaptor Proteins, Signal Transducing/genetics , GTPase-Activating Proteins/genetics , Gene Expression Regulation , Hypotrichosis/genetics , Lymphangiogenesis/genetics , Lymphedema/genetics , Telangiectasis/genetics , Adaptor Proteins, Signal Transducing/metabolism , Animals , Cell Movement/genetics , Disease Models, Animal , Endothelial Cells/metabolism , Female , GTPase-Activating Proteins/metabolism , Lymphatic Vessels/metabolism , Mice , Mice, Knockout , SOXF Transcription Factors/genetics , SOXF Transcription Factors/metabolism , Syndrome , Vascular Endothelial Growth Factor C/genetics , Vascular Endothelial Growth Factor C/metabolism , ZebrafishABSTRACT
Annexin A1 (AnxA1) is a candidate regulator of the epithelial- to mesenchymal (EMT)-like phenotypic switch, a pivotal event in breast cancer progression. We show here that AnxA1 expression is associated with a highly invasive basal-like breast cancer subtype both in a panel of human breast cancer cell lines as in breast cancer patients and that AnxA1 is functionally related to breast cancer progression. AnxA1 knockdown in invasive basal-like breast cancer cells reduced the number of spontaneous lung metastasis, whereas additional expression of AnxA1 enhanced metastatic spread. AnxA1 promotes metastasis formation by enhancing TGFbeta/Smad signaling and actin reorganization, which facilitates an EMT-like switch, thereby allowing efficient cell migration and invasion of metastatic breast cancer cells.
