Medicine and Health Sciences Commons^™

Role Of Extracellular Signal-Regulated Kinase (Erk) In Regulation Of Intestinal Epithelial Tight Junctions, Sudhir Aggarwal

Theses and Dissertations (ETD)

Evidence indicates that MAP kinase (ERK1/2) is involved in regulation of epithelial tight junctions. There are different opinions expressed by investigators as to whether ERK disrupts the junctions or protects them. ERK has also been demonstrated to mediate the EGF-caused protection of the intestinal epithelial tight junctions (TJ) from hydrogen peroxide. Studies using pharmacological inhibitors have shown that EGF increases Thr-phosphorylation of occludin by a MAP kinase-dependent mechanism. This study aimed at looking at the role of ERK in regulation of tight junctions using pharmacological and molecular techniques.

Hypothesis: ERK protects tight junctions in differentiated Caco-2 cells, while it is …

D2r Dopamine Receptor Mediates Changes In Dual Specificity Phosphatase Expression In A Small Cell Lung Cancer Cell Line, Scott Lemar Lattimer

Theses and Dissertations (ETD)

Bromocriptine, a D2 dopamine receptor (D2R) agonist, is used clinically as a treatment for pituitary tumors of a lactotroph origin. Many questions remain unanswered about the mechanism of this effect. The antiproliferative effect has not been demonstrated in DMS 53 cell line, a Small Cell Lung Cancer (SCLC). In this thesis, we have shown that treatment with NPA (N‑propylnorapomorphine), a dopamine receptor agonist inhibits ERK phosphorylation and proliferation in DMS 53 cells. NPA treatment causes significant increases in DUSP‑1 (MKP‑1), DUSP‑4 (MKP‑2) and DUSP5 mRNA. NPA treatment also correlates with increases in DUSP5 (hVHR3) protein visualized using Western Blot. These …