Regulatory Role of the NF-kB Pathway in Lymphangiogenesis and Breast Cancer Metastasis
Abstract
Elevation of VEGFR-3, the primary mediator of lymphangiogenesis (i.e., new lymphatic vessel formation), is frequently associated with inflammation related to chronic disease and cancer. In the latter case, VEGFR-3 dependent lymphangiogenesis induced by inflamed tumors increases the incidence of distant metastasis, leading to decreased patient survival. However, the molecular mechanisms underlying inflammation-induced VEGFR-3 elevation and lymphangiogenesis are currently unknown. Two potential candidate genes that may regulate expression of VEGFR-3 are Prox1, the primary mediator of embryonic lymphangiogenesis, and NF-kB, the key intracellular regulator of inflammation-induced transcription. We hypothesized that the key inflammatory mediator, NF-kB, regulates transcription of key mediators of lymphangiogenesis, VEGFR-3 and Prox1. We further hypothesized that inflammation-induced elevation of VEGFR-3 and Prox1 are essential steps required for robust lymphangiogenesis in response to inflammation. The three primary goals of this study were to (1) delineate the time-course of events leading to inflammation-induced lymphangiogenesis in vivo; (2) clone and characterize the VEGFR-3 promoter and identify factors regulating VEGFR-3 expression in vitro; and (3) characterize the lymphatic phenotype of NF-kB p50 knockout mice. To begin testing these hypotheses, we used a mouse model of peritonitis to characterize induction of lymphangiogenesis and expression kinetics of NF-kB, Prox1 and VEGFR-3. In vivo time-course analysis of inflammationinduced lymphangiogenesis showed activation of NF-kB followed by sequential upregulation of Prox1 and VEGFR-3 that preceded lymphangiogenesis by 4 and 2 days, respectively. Characterization of the VEGFR-3 promoter by luciferase-reporter and ChIP assays showed direct activation by Prox1, NF-kB p50 and p65 transcription factors. This also revealed that Prox1 and NF-kB p50 bind in close proximity and synergistically activate the VEGFR-3 promoter.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2010
- Accession Number
- ADA541482
Entities
People
- Michael J Flister
- Sophia Ran
Organizations
- Southern Illinois University School of Medicine