Abstract P1-02-05: EPLIN? Can Negatively Impact on Angiogenesis and Is Associated with ERK Signalling

Abstract

Abstract Background: EPLIN (epithelial protein lost in neoplasm) is a cytoskeletal associated protein involved in regulating actin dynamics and cell motility. EPLIN expression is frequently lost in cells as they progress to a cancer state and this loss may account for enhanced cancer cell motility. EPLIN has also been shown to be lost in clinical breast cancer, which is associated with patients clinical outcome. Recently, EPLIN has been linked to ERK signalling. This study examined the potential of EPLIN to influence the angiogenesis process and its links to ERK in endothelial cells Methods: Over-expression of EPLIN α was achieved through transfection of the vascular endothelial cell, HECV, with a mammalian expression construct containing the full coding sequence of EPLINα. Enhanced levels of EPLINα were verified through RT-PCR, Q-PCR and Western blot analysis before assessing the angiogenic potential of control and transfected cells using angiogenesis and cell migration models. Treatment of transfected and control cells with ERK inhibitor was used to assess the potential interaction between EPLINα and ERK in endothelial cells. Results: Substantial enhancement in EPLINα expression was seen in transfected cells compared to control cells at both transcript and protein level. Over-expression of EPLINα in HECV endothelial cells resulted in a reduced capacity, compared to control, of these cells to form tubule like structures in an in vitro angiogenesis tubule formation assay (6566 +/− 856µm tubule perimeter of control cells vs 2881 +/− 546µm EPLINα overexpressing HECV cells, p = 0.007). This was seen together with a reduced cell migration following overexpression of EPLINα in the cells. Treatment of control cells with ERK inhibitor significantly reduced tubule formation (3537 +/− 277µm tubule perimeter of ERK inhibitor treated control cells vs 6566 +/− 856µm total perimeter of untreated control cells, p = 0.01), however treatment of HECV cells transfected with EPLINα expression construct caused tubule formation levels to return to control levels (6566 +/− 856µm tubule perimeter of untreated control cells vs 5326 +/− 784µm tubule perimeter of ERK inhibitor treated EPLINα overexpressing HECV cells, p = 0.317). Discussion: EPLINα can negatively influence tubule formation in vitro and thus may impact on the angiogenesis process. Furthermore, its impact on tubule formation appears to be linked to ERK signalling. Together, this study suggests a role for EPLINα in angiogenesis, which may be linked with ERK signalling. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-02-05.