Maertens Ludovic, Erpicum Charlotte, Detry Benoit, Blacher Silvia, Lenoir Bénédicte, Carnet Oriane, Péqueux Christel, Cataldo Didier, Lecomte Julie, Paupert Jenny, Noel Agnès
Laboratory of Tumor and Development Biology, Groupe Interdisciplinaire de Génoprotéomique Appliquée - Cancer (GIGA-Cancer), University of Liège, Liège, Belgium.
Laboratory of Cardiovascular Research, Centre de Recherche Public de la santé (CRP-santé), Luxembourg, Luxembourg.
PLoS One. 2014 Sep 15;9(9):e106976. doi: 10.1371/journal.pone.0106976. eCollection 2014.
It is now well accepted that multipotent Bone-Marrow Mesenchymal Stem Cells (BM-MSC) contribute to cancer progression through several mechanisms including angiogenesis. However, their involvement during the lymphangiogenic process is poorly described. Using BM-MSC isolated from mice of two different backgrounds, we demonstrate a paracrine lymphangiogenic action of BM-MSC both in vivo and in vitro. Co-injection of BM-MSC and tumor cells in mice increased the in vivo tumor growth and intratumoral lymphatic vessel density. In addition, BM-MSC or their conditioned medium stimulated the recruitment of lymphatic vessels in vivo in an ear sponge assay, and ex vivo in the lymphatic ring assay (LRA). In vitro, MSC conditioned medium also increased the proliferation rate and the migration of both primary lymphatic endothelial cells (LEC) and an immortalized lymphatic endothelial cell line. Mechanistically, these pro-lymphangiogenic effects relied on the secretion of Vascular Endothelial Growth Factor (VEGF)-A by BM-MSC that activates VEGF Receptor (VEGFR)-2 pathway on LEC. Indeed, the trapping of VEGF-A in MSC conditioned medium by soluble VEGF Receptors (sVEGFR)-1, -2 or the inhibition of VEGFR-2 activity by a specific inhibitor (ZM 323881) both decreased LEC proliferation, migration and the phosphorylation of their main downstream target ERK1/2. This study provides direct unprecedented evidence for a paracrine lymphangiogenic action of BM-MSC via the production of VEGF-A which acts on LEC VEGFR-2.
目前已广泛接受的观点是，多能骨髓间充质干细胞（BM-MSC）通过包括血管生成在内的多种机制促进癌症进展。然而，它们在淋巴管生成过程中的作用却鲜有描述。我们使用从两种不同背景的小鼠中分离出的BM-MSC，证明了BM-MSC在体内和体外均具有旁分泌淋巴管生成作用。将BM-MSC与肿瘤细胞共同注射到小鼠体内可增加体内肿瘤生长和肿瘤内淋巴管密度。此外，BM-MSC或其条件培养基在体内的耳海绵试验以及体外的淋巴环试验（LRA）中均能刺激淋巴管的募集。在体外，MSC条件培养基还能提高原代淋巴管内皮细胞（LEC）和永生化淋巴管内皮细胞系的增殖率和迁移能力。从机制上讲，这些促淋巴管生成作用依赖于BM-MSC分泌血管内皮生长因子（VEGF）-A，其激活LEC上的VEGF受体（VEGFR）-2通路。实际上，可溶性VEGF受体（sVEGFR）-1、-2将VEGF-A捕获在MSC条件培养基中，或使用特异性抑制剂（ZM 323881）抑制VEGFR-2活性，均会降低LEC的增殖、迁移及其主要下游靶点ERK1/2的磷酸化。本研究为BM-MSC通过产生作用于LEC VEGFR-2的VEGF-A发挥旁分泌淋巴管生成作用提供了前所未有的直接证据。
