• The Effects of Perfuorooctanoic Acid on Expression of Estrogen Receptor Alpha MRNA and Protein in Mcf-7 Cells

      Gillen, Laura; Peloquin, Rachel; Department of Biological Sciences (2016-03)
      Endocrine disruptors, such as Perfluorooctanoic acid (PFOA), are known to interfere with normal hormonal processes and could lead to detrimental effects on development and reproduction. PFOA is a ligand to peroxisome proliferator-activated receptors (PPARs), which have been demonstrated to crosstalk with estrogen receptors. Previous studies in our lab have demonstrated that treatment of MCF-7 breast cancer cells with 100μM PFOA significantly decreases cell viability. As both isoforms of the estrogen receptor (ER), alpha and beta, have been shown to regulate proliferation and apoptosis, this study aims to determine whether the decrease in viability is associated with changes in the expression of estrogen receptor. Cells were treated for 24h and 48h with vehicle (DMSO), 50μM and 100μM PFOA then harvested for either RNA or protein isolation. PCR analysis revealed minimal expression of ER beta in MCF-7 cells, consistent with the literature. ER alpha mRNA levels were significantly reduced by 24h in cells treated with both 50μM and 100μM PFOA. We are in the process of running western blots to determine whether or not there is a similar decrease in ER alpha protein levels in MCF-7 cells treated with PFOA. Funding Source: Center for Undergraduate Research and Scholarship and Department of Biological Sciences
    • Peroxynitrite Mediates Diabetes-Induced Endothelial Dysfunction: Possible Role of Rho Kinase Activation

      El-Remessy, Azza B.; Tawfik, Huda E.; Matragoon, Suraporn; Pillai, Bindu; Caldwell, Ruth B.; Caldwell, Robert William; Department of Pharmacology and Toxicology; Vascular Biology Center (2010-11-1)
      Endothelial dysfunction is characterized by reduced bioavailability of NO due to its inactivation to form peroxynitrite or reduced expression of eNOS. Here, we examine the causal role of peroxynitrite in mediating diabetes-induced endothelial dysfunction. Diabetes was induced by STZ-injection, and rats received the peroxynitrite decomposition catalyst (FeTTPs, 15â mg/Kg/day) for 4 weeks. Vasorelaxation to acetylcholine, oxidative-stress markers, RhoA activity, and eNOS expression were determined. Diabetic coronary arteries showed significant reduction in ACh-mediated maximal relaxation compared to controls. Diabetic vessels showed also significant increases in lipid-peroxides, nitrotyrosine, and active RhoA and 50% reduction in eNOS mRNA expression. Treatment of diabetic animals with FeTTPS blocked these effects. Studies in aortic endothelial cells show that high glucose or peroxynitrite increases the active RhoA kinase levels and decreases eNOS expression and NO levels, which were reversed with blocking peroxynitrite or Rho kinase. Together, peroxynitrite can suppress eNOS expression via activation of RhoA and hence cause vascular dysfunction.