ABSTRACT
The interaction between vascular endothelial cells (ECs) and cancer cells is of vital importance to understand tumor dissemination. A paradigmatic cancer to study cell-cell interactions is classical Hodgkin Lymphoma (cHL) owing to its complex microenvironment. The role of the interplay between cHL and ECs remains poorly understood. Here we identify canonical WNT pathway activity as important for the mutual interactions between cHL cells and ECs. We demonstrate that local canonical WNT signaling activates cHL cell chemotaxis toward ECs, adhesion to EC layers and cell invasion using not only the Wnt-inhibitor Dickkopf, tankyrases and casein kinase 1 inhibitors but also knockdown of the lymphocyte enhancer binding-factor 1 (LEF-1) and ß-catenin in cHL cells. Furthermore, LEF-1- and ß-catenin-regulated cHL secretome promoted EC migration, sprouting and vascular tube formation involving vascular endothelial growth factor A (VEGF-A). Importantly, high VEGFA expression is associated with a worse overall survival of cHL patients. These findings strongly support the concept that WNTs might function as a regulator of lymphoma dissemination by affecting cHL cell chemotaxis and promoting EC behavior and thus angiogenesis through paracrine interactions.
Subject(s)
Cell Communication , Endothelial Cells/metabolism , Hodgkin Disease/metabolism , Hodgkin Disease/pathology , Tumor Microenvironment , Wnt Signaling Pathway , Cell Adhesion/genetics , Cell Line , Cell Movement/genetics , Chemokine CCL19/metabolism , Chemotaxis/genetics , Chemotaxis/immunology , Hodgkin Disease/genetics , Hodgkin Disease/immunology , Humans , Lymphoid Enhancer-Binding Factor 1/genetics , Lymphoid Enhancer-Binding Factor 1/metabolism , Neovascularization, Pathologic , Tumor Microenvironment/genetics , Tumor Microenvironment/immunology , Vascular Endothelial Growth Factor A/metabolism , beta Catenin/genetics , beta Catenin/metabolismABSTRACT
Classical Hodgkin lymphoma (cHL) has a typical clinical manifestation, with dissemination involving functionally neighboring lymph nodes. The factors involved in the spread of lymphoma cells are poorly understood. Here we show that cHL cell lines migrate with higher rates compared with non-Hodgkin lymphoma cell lines. cHL cell migration, invasion and adhesion depend on autocrine WNT signaling as revealed by the inhibition of WNT secretion with the porcupine inhibitors Wnt-C59/IWP-2, but did not affect cell proliferation. While application of recombinant WNT5A or WNT5A overexpression stimulates HL cell migration, neither WNT10A, WNT10B nor WNT16 did so. Time-lapse studies revealed an amoeboid type of cell migration modulated by WNT5A. Reduced migration distances and velocity of cHL cells, as well as altered movement patterns, were observed using porcupine inhibitor or WNT5A antagonist. Knockdown of Frizzled5 and Dishevelled3 disrupted the WNT5A-mediated RHOA activation and cell migration. Overexpression of DVL3-K435M or inhibition of ROCK (Rho-associated protein kinase) by Y-27632/H1152P disrupted cHL cell migration. In addition to these mechanistic insights into the role of WNT5A in vitro, global gene expression data revealed an increased WNT5A expression in primary HL cells in comparison with normal B-cell subsets and other lymphomas. Furthermore, the activity of both porcupine and WNT5A in cHL cells had an impact on lymphoma development in the chick chorionallantoic membrane assay. Massive bleeding of these lymphomas was significantly reduced after inhibition of WNT secretion by Wnt-C59. Therefore, a model is proposed where WNT signaling has an important role in regulating tumor-promoting processes.
