Abstract P3-12-07: Voyagers and their aids: The role of interactions between tumor and endothelial cells in brain metastasis

Abstract

Abstract Clinically, brain metastases are most commonly observed in breast, lung, and melanoma cancers. When a tumor cell leaves its site of origin, it enters a nearby blood vessel on a voyage to find a new tissue to invade. These circulating tumor cells will act as voyagers and they interact with a endothelial cell. For example, in the case of brain metastasis, tumor cells need to adhere to brain endothelial cells before they can invade into the surrounding brain tissue. Thus, investigating the mechanisms of tumor and endothelial cell interactions can serve as a very powerful tool to inhibit the voyage of these tumor cells and prevent the formation of metastases. In this study, we performed trans-endothelial migration assay using HBMVEC cells to study tumor-endothelial interactions. In general, HBMVEC cells were seeded to BD-Falcon cell culture inserts at a density of 2 × 105 cells and allowed to grow for 24 hours to form a confluent monolayer and GFP expressing tumor cells (MCF-7, Akt3 overexpressing MCF7, MDA-MB-231 and MDA-MB-231-BR) were incubated at suitable interval at 37°C. At the end of incubation period, cells were fixed and number of tumor cells that will penetrate the monolayer of HBMEC were counted using Phase-contrast microscope in 12 different visual fields. Transmigrating tumor cells are thought to be able to overcome the endothelial barrier by inducing changes within endothelial cells. We identified the molecular changes responsible for such adhesion and invasion by cell sorting for gene expression analysis. After co-culturing the HBMEC (after transfecting with Mcherry protein) with GFP expressing tumor cells and Mcherry labeled HBMEC, we used cell sorting to separate tumor and HBMEC cells. After sorting the tumor cells and endothelial cells from co-culture, (MCF-7 monolayer vs MCF-7 co-cultured, MDA-MB-231 monolayer vs MDA-MB-231 co-cultured, HBMEC monolayer vs HBMEC co-cultured) gene expression analysis was performed using SABiosciences cell adhesion assay kit to accurately capture the genetic changes that occured in the tumor and endothelial cells upon co-culture. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-12-07.