Education

Research in my laboratory focuses on the role of the insulin-like growth factors (IGF) in mammary gland growth and development. A specific focus is to understand the molecular and cellular mechanisms by which these growth factors regulate growth, differentiation and cell survival of mammary epithelial cells. This cell type is responsible for milk synthesis and is also a common site of origin of mammary carcinoma. The IGFs associate with a family of high-affinity binding proteins (IGFBP) which modulate their biological activity. For example we have found that IGF-I specifically stimulates the synthesis of IGF binding protein-3 by mammary epithelial cells. When these cells are transfected to overexpress this protein, they exhibit enhanced responsiveness to IGF-I in terms of DNA synthesis. We are currently investigating the mechanisms underlying this observation. Specific areas of research include:

•	regulation of IGF binding protein gene transcription
•	the role of IGF and IGF binding protein-3 in regulating growth, differentiation and apoptosis of mammary epithelial cells
•	signal transduction pathways by which IGF-I regulates growth of mammary epithelial cells and mammary fibroblasts
•	interactions between the extracellular matrix and growth factors in the mammary gland

Special Techniques

A wide range of cellular and molecular techniques are used in our laboratory. These include mammalian cell culture, nucleic acid and protein electrophoresis, Northern and Western analysis, PCR, transient transfection promoter assays, nuclear run-on analysis, and gel shift mobility assays.

Members of the Cohick Lab

Jodie Fleming, Ph.D. student. Dissertation title: The role of IGF in mediating stromal-epithelial interactions in the mammary gland.

Brian Leibowitz, Ph.D. student. Dissertation title: Molecular Regulation of IGFBP-3 Expression and its Role in Apoptosis in Mammary Epithelial Cells.

Dr. Amanda Jetzt, Senior Research Associate.

Representative Publications

Fleming JM, Leibowitz BJ, Kerr DE, Cohick WS. 2005 IGF-I differentially regulates IGF binding protein expression in primary mammary fibroblasts and epithelial cells. J Endocrinol 186 (July):165-178.

Sivaprasad U, Fleming J, Verma PS, Hogan KA, Desury G, Cohick WS. 2004 Stimulation of insulin-like growth factor (IGF) binding protein-3 synthesis by IGF-I and transforming growth factor-α is mediated by both phosphatidylinositol-3 kinase and mitogen-activated protein kinase pathways in mammary epithelial cells. Endocrinology 145:4213-4221.

Cornwell T, Cohick WS, Raskin I. 2004 Dietary phytoestrogens and health. Phytochemistry 65:995-1016.

Grill CJ, Sivaprasad U, Cohick WS. 2002 Constitutive expression of IGF binding protein-3 by mammary epithelial cells alters signaling through akt and p70S6 kinase. J Mol Endocrinol 29:153-162.

Grill CJ, Cohick WS, Sherman A. 2001 Postnatal development of the rat mammary gland is preserved during iron deficiency. J Nutrition 131:1444-1448

Cohick WS, Wang B, Verma P, Boisclair Y. 2000. Insulin-like growth factor-I and cyclic AMP regulate IGF binding protein-3 gene expression by transcriptional and post-transcriptional mechanisms in mammary epithelial cells. Endocrinology 4583-4591.

Grill CJ, Cohick WS. 2000. Insulin-like growth factor binding protein-3 mediates IGF-I action in a bovine mammary epithelial cell line independent of an IGF interaction. J Cellular Physiology 183:273-283

Cohick WS, Turner JD. 1998 Regulation of IGF binding protein synthesis by a bovine mammary epithelial cell line. J Endocrinol 157:326-336.

Cohick WS. 1998 Role of the insulin-like growth factors and their binding proteins in lactation. J Dairy Sci 81:1769-1777.

Schoknecht PA, McGuire MA, Cohick WS, Currie WB, Bell AW. 1996 Effect of chronic infusion of placental lactogen on ovine fetal growth in late gestation. Dom Anim Endocrinol 13:519- 528.

Cohick WS, Armstrong JD, Whitacre MD, Lucy MC, Harvey RW, Campbell RM. 1996 Ovarian expression of insulin-like growth factor-I (IGF-I), IGF binding proteins and growth hormone receptor in heifers actively immunized against growth hormone releasing factor. Endocrinology 137:1670-1677.

Cohick WS, Gockerman A, Clemmons DR. 1995 Regulation of insulin-like growth factor (IGF) binding protein-2 synthesis and degradation by PDGF and the IGFs is enhanced by serum deprivation in vascular smooth muscle cells. J Cell Physiol 64:187-196.

McGuire MA, Bauman DE, Dwyre DA, Cohick WS. 1995 Nutritional modulation of the somatotropin/insulin-like growth factor system: response to feed deprivation in lactating cows. J Nutrition 125:492-502.

Cohick WS, Clemmons DR. 1994 Enhanced expression of dihydrofolate reductase by bovine kidney epithelial cells results in altered cell morphology, IGF-I responsiveness and IGFBP-3 expression. J Cell Physiol 161:178-186.

Stanko RL, Cohick WS, Armstrong JD, Shaw DW, Harvey RW, Clemmons DR, Whitacre MD. 1994 Effect of somatotropin and (or) pregnant mare serum gonadotropin on serum and follicular IGF-I and IGF binding proteins in cattle. Biol Reprod 50:290-300.

More publications.

National Committees

Milk synthesis committee, American Dairy Science Association

Professional Societies

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