Characterization of the effects of the chemopreventive agent conjugated linoleic acid (CLA) on target stromal cell populations
Boniface, Ryan Lawrence
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Conjugated linoleic acid is a dietary fatty acid which induces apoptosis in mammary adipose vascular endothelium and decreases mammary adipose tissue. Studies have shown that stromal cells can affect the growth and differentiation of adjacent epithelial cells. The purpose of this study is to test whether CLA effects the stromal deposition of fibroblast cell populations in the amount, composition, and organization of the stromal proteins. In vitro studies were performed with WI38 fibroblast cell lines that were fed with media containing 50μM 9,11-CLA or 50μM 10,12-CLA. The stromal changes were visualized on a per cell basis by immunofluorescence, studied by SDS-PAGE western blotting, and 2D-DIGE. In vivo studies were conducted using trichrome stained 5μm paraffin embedded sections from mouse and rat mammary glands fed dietary CLA. Stromal depositions around mammary ducts were measured in relation to the ductal width. CLA induced significant increases in stromal deposition around mammary ducts. In vivo in the mouse supplemented with 9,11- and 10,12-CLA. In the rat model, neither 9,11- or 10,12-CLA were effective in inducing changes in mammary gland morphology. In vitro, CLA was shown to increase the ECM proteins fibronectin and tenascin. Proteomic changes were tested by performing 2D-DIGE, 10,12-CLA was effective in vitro at increasing the expression of annexin A1. Western blotting was performed to quantitate ECM changes induced by CLA in fibroblast cells. These studies suggest that stromal cells and secreted proteins can be altered by the direct effects of dietary fatty acid in vitro.