The Effect of the Notch Signal Pathway on the Expression of Matrix Metalloproteinase 2 and Tissue Inhibitor of Metalloproteinase 2 in Lymphangiogenesis
Author:Aaron van Loon
Mentor:Donna Nofziger-Plank, Associate Professor of Biology, Pepperdine University
Matrix metalloproteinases (MMPs) expression is an essential component of the process of lymphangiogenesis but little is known about the regulation of these proteins in lymphatic endothelial cells. The Notch signaling pathway has been shown to regulate the expression of MMPs during angiogenesis using human umbilical vein endothelial cells. In this study the effect of Notch signaling on MMP expression was analyzed in human lymphatic endothelial cells (HLECs). Using lentivirus vectors, two mutant forms of Notch1 and a green fluorescent protein (GFP) control were transduced into HLECs. The mutant forms of Notch consisted of a constitutively activated form and the other was a dominant negative form. Following transductions, the HLEC's were treated with either Vascular Endothelial Growth Factor (VEGF) A or C. Total RNA was collected, converted to complementary DNA (cDNA) and semi-quantitative polymerase chain reactions (PCR) were run using primers for MMP-2 and TIMP-2 to determine differences in expression between each Notch1/VEGF treatment. A significant decrease in MMP-2 and TIMP-2 expression was detected between the GFP control and the constitutively active Notch1. In addition, when when VEGF-A or C is combined with the constitutively active Notch1, this inhibition is further increased. Taking into consideration the role of lymphangiogenesis in tumor cell metastasis, these findings may contribute to the development of more effective cancer treatments.