Barnes, Jill, DVM, PhD
Teaching Associate Professor of Anatomy and Cell Biology
D.V.M.: North Carolina State University, 1992
Ph.D.: North Carolina State University, 1998
Post-doctoral: National Research Council, United States Environmental Protection Agency, 2001
Office Phone: (919) 513-6372
Lab Phone:(919) 513-6356
Fax: (919) 513-6465
Research in our laboratory is focused on investigating the role of stress proteins (heat shock proteins) in cytoprotection and carcinogenesis.
Heat shock proteins (Hsps) belong to the highly conserved family of stress proteins, some of which are induced by a variety of cellular stresses, environmental factors and pathological conditions. The stress response, i.e. synthesis of heat shock proteins, allows cells to adapt to changes in their environment and to survive in otherwise lethal conditions. The ability of Hsps to protect a wide variety of cells and tissues from apoptosis and necrosis is well demonstrated. However, the specific mechanisms of this protection are still under investigation. In addition, Hsps are often expressed in cancer tissues and appear to be associated with increased cell proliferation and resistance to anticancer therapies.
The present studies are aimed at using a tetracycline-regulated gene expression in human MCF-7 breast cancer cells to examine the specific effects of inducible Hsp70 on cell growth and protection against the cytotoxicity of hyperthermia and various chemical agents. Using this unique cell line/expression system, we have shown that overexpression of Hsp70 stimulates cell proliferation and protects against the cytotoxicity of heat and DNA damage induced by exposure to sodium arsenite and vincristine.
We are currently evaluating the molecular and cellular mechanisms responsible for the effects of Hsp70 on cell growth by evaluating the role of Hsp expression on estrogen signaling pathways. Using our MCF-7 Hsp70 overexpressing cell lines, preliminary data demonstrates that inducible Hsp70 associates with estrogen receptors (ER a ). Furthermore, MCF-7 cells with elevated levels of Hsp70 show a significant increase in estrogen-induced estrogen response element (ERE) reporter activity and cell growth as compared with cells expressing control levels of Hsp70. The differential effects of Hsp70 on cell growth and ER activity are abolished by the addition of tamoxifen (antiestrogen), indicating an ER-mediated mechanism. These studies suggest that the inducible chaperone, Hsp70, plays an important role in ER action and estrogen-induced cell growth.
In addition to elucidating the effects of Hsp expression on cell growth, we are also investigating the range and type of cytoprotection provided by Hsp70 following exposure to chemotherapeutic agents with different mechanisms of action. We are currently investigating the effects of Hsp70 overexpression following exposure to adriamycin (topoisomerase inhibitor), taxol (microtubule inhibitor) and the Hsp70 inhibitor,17-AAG. This data will permit us to gauge drug resistance with a substantial impact on selection of the most appropriate therapies for cancer treatment.
Mammalian cell culture, expression vector construction, cDNA microarray, DNA transfections, Western blotting, Apoptosis assays, Immunofluorescence, Micronucleus assay, DNA and RNA isolations, Flow cytometry, real-time PCR, ChIP, reporter assays, Co-IP.
Barnes JA, Collins BW, Dix DJ, Allen JW (2002) Effect of Heat Shock Protein 70 (HSP70) expression on arsenite induced genotoxicity. Environ Mol Mutagen 40(4):236-242.
Barnes JA, Dix DJ, Collins BW, Luft C, Allen JW (2001). Expression of inducible HSP70 enhances the proliferation of MCF-7 breast cancer cells and protects against the cytotoxic effects of hyperthermia. Cell Stress & Chaperones;6:316-325.
Barnes, J.A. and Smoak, I.W. (2000) Glucose-regulated protein 78 (GRP78) is elevated in embryonic mouse heart and induced following hypoglycemic stress. Anatomy and Embryology. 202 67-74.
Barnes, J.A., Smoak, I.W. and Branch, S. (1999) Expression of glucose-regulated proteins (GRP78 and GRP94) in hearts and fore-limb buds of mouse embryos exposed to hypoglycemia in vitro. Cell Stress and Chaperones. 4(4) 250-258.
Barnes, J.A. and Smoak, I.W. (1997) Immunolocalization and heart levels of GRP94 in the mouse during post-implantation development. Anatomy and Embryology.196(4) 335-341.