Molecular profiling of lymphatic endothelial cells activation in vitro
The lymphatic vascular system plays a key role in cancer progression. Indeed, the activation of lymphatic endothelial cells (LECs) through the lymphangiogenic process allows the formation of new lymphatic vessels (LVs) that represent the major route for dissemination of solid tumors. This process is governed by a plethora of cancer-derived and microevironmental mediators that strictly activate and control specific molecular pathways in LECs. In this work we used an in vitro model of LEC activation to trigger lymphangiogenesis using a mix of recombinant pro-lymphangiogenic factors (VFS) and a co-culture system with human melanoma cells. Both systems efficiently activated LECs, and under these experimental conditions RNA sequencing was exploited to unveil the transcriptional profile of activated LECs.  Our data demonstrate that both recombinant and tumor cell-mediated activation trigger significant molecular pathways associated with endothelial activation, morphogenesis and cytokine-mediated signaling. In addition, this system provides information on new genes to be further investigated in the lymphangiogenesis process and open the possibility for further exploitation in other tumor contexts where lymphatic dissemination plays a relevant role. Overall design: RNA-Seq of lymphatic endothelial cells (LEC) activated by a mix of recombinant pro-lymphangiogenic factors and an RNA-Seq of LEC a co-cultured with human melanoma cells. Both systems efficiently activated LECs.