title: TIE-2-expressing monocytes are lymphangiogenic and associate specifically with lymphatics of human breast cancer.
abstract: In experimental mouse models of cancer, increasingly compelling evidence point toward a contribution of tumor associated macrophages (TAM) to tumor lymphangiogenesis. Corresponding experimental observations in human cancer remain scarce although lymphatic metastasis is widely recognized as a predominant route for tumor spread. We previously showed that, in malignant tumors of untreated breast cancer (BC) patients, TIE-2-expressing monocytes (TEM) are highly proangiogenic immunosuppressive cells and that TIE-2 and VEGFR signaling pathways drive TEM immunosuppressive function. We report here that, in human BC, TEM express the canonical lymphatic markers LYVE-1, Podoplanin, VEGFR-3 and PROX-1. Critically, both TEM acquisition of lymphatic markers and insertion into lymphatic vessels were observed in tumors but not in adjacent non-neoplastic tissues, suggesting that the tumor microenvironment shapes both TEM phenotype and spatial distribution. We assessed the lymphangiogenic activity of TEM isolated from dissociated primary breast tumorsin vitroandin vivousing endothelial cells (EC) sprouting assay and corneal vascularization assay, respectively. We show that, in addition to their known hemangiogenic function, TEM isolated from breast tumor display a lymphangiogenic activity. Importantly, TIE-2 and VEGFR pathways display variable contributions to TEM angiogenic and lymphangiogenic activities across BC patients; however, combination of TIE-2 and VEGFR kinase inhibitors abrogated these activities and overcame inter-patient variability. These results highlight the direct contribution of tumor TEM to the breast tumor lymphatic network and suggest a combined use of TIE-2 and VEGFR kinase inhibitors as a therapeutic approach to block hem- and lymphangiogenesis in BC.
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: Sylvian
authors.initials: S
authors.lastname: Bron
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne, Lausanne, Switzerland; Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
authors.forename: Luc
authors.initials: L
authors.lastname: Henry
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: Eveline
authors.initials: E
authors.lastname: Faes-Van't Hull
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Turrini
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: Dominique
authors.initials: D
authors.lastname: Vanhecke
authors.affiliation: Vital-IT, Swiss Institute of Bioinformatics, University of Lausanne , Lausanne, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Guex
authors.affiliation: Department of Gynecology and Obstetrics, CHUV , Lausanne, Switzerland.
authors.forename: Assia
authors.initials: A
authors.lastname: Ifticene-Treboux
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Marina Iancu
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Semilietof
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Rufer
authors.affiliation: Institute of Pathology, Johannes Gutenberg University , Mainz, Germany.
authors.forename: Hans-Anton
authors.initials: HA
authors.lastname: Lehr
authors.affiliation: Vital-IT, Swiss Institute of Bioinformatics, University of Lausanne , Lausanne, Switzerland.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Xenarios
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: George
authors.initials: G
authors.lastname: Coukos
authors.affiliation: Department of Gynecology and Obstetrics, CHUV , Lausanne, Switzerland.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Delaloye
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne , Lausanne, Switzerland.
authors.forename: Marie-Agnès
authors.initials: MA
authors.lastname: Doucey
keywords: Angiogenesis; TIE-2-expressing monocytes; breast cancer; lymphatics; tumor microenvironment