The University of Georgia College of Veterinary Medicine

Georgia Veterinary Scholars Program

GVSP Summer 2011 Scholars

Georgia Veterinary Scholar	Faculty Mentor

Erica Noland UGA College of Veterinary Medicine Class of 2014	Dr. Rabindranath De La Fuente Department of Physiology and Pharmacology UGA College of Veterinary Medicine

Role of Chromatin Remodeling Proteins in Chromosome Instability of Canine Mammary Gland Carcinomas

Erica Noland, Claudia Baumann, Rabindranath De La Fuente

Mammary cancer is a leading cause of death in female dogs and the fifth cause of death in women. Abnormal chromosome number, or aneuploidy, is an identifying characteristic of cells that have undergone malignant neoplastic transformation. An altered epigenetic composition has been shown to play a role in genomic instability and consequently the onset of tumor formation and malignant progression. We hypothesize that chromatin remodeling proteins are abnormally regulated in an established canine mammary gland cancer cell line. Using live cell imaging, we have made novel attempts to detect abnormal chromosome segregation in actively dividing cells. Immunofluorescent microscopy was applied to detect the subcellular localization of chromatin remodeling proteins. We provide novel evidence that poly (ADP-ribose) polymerase (Parp-1) co-localizes with CREST signals at the kinetochores in canine mammary gland cells. Localization may be cell cycle dependent. Rampant aneuploidy was detected in the cancer cell line. Moreover, micronuclei formation consisting of whole missegregated chromosomes and acentric chromosome fragments were observed. Chromosome breaks were detected using γH2AX. Using semi-quantitative PCR, Parp-1 gene expression will be compared across canine cancer and normal mammary gland cell lines. Protein levels will be measured by Western Blot. In addition, Rad51 expression levels will be analyzed due to its clinical relevance and role in DNA repair by homologous recombination. Tissue specimens of varying malignancy will be compared to match the epigenetic profile with the degree of progression. These molecular markers could potentially be used in the early detection of cells that may lead to tumor formation as well as insight into treating or managing clinical cases. Understanding the mechanisms that cause chromosome instability, and consequently aneuploidy, is a step towards designing drugs that target these processes. In a one health initiative, findings could have immediate application to veterinary medicine and future applications to human medicine.