Two MD Anderson faculty named as prestigious AAAS Fellows

Distinguished contributions to understanding p53 tumor suppression in stem cells and breakthrough advances in treating breast cancer have earned two scientists at The University of Texas MD Anderson Cancer Center membership in a notable association of scholars.

Michelle C. Barton, Ph.D., dean, The University of Texas Graduate School of Biomedical Sciences at Houston (GSBS) and professor of Epigenetics and Molecular Carcinogenesis, and Gabriel Hortobagyi, M.D., professor and former chair of MD Anderson’s Breast Medical Oncology have been named Fellows of the American Association for the Advancement of Science (AAAS).

Understanding p53 tumor suppressor functions, Barton’s research focuses on basic mechanisms of regulated and aberrant gene expression during differentiation, tissue regeneration, and cancer, especially as dictated by members of the p53- family, their interacting protein partners, and chromatin structure.

P53 is a gene that codes for a protein that regulates the cell cycle and functions as a tumor suppressor gene. Traditionally p53 is studied in cultured cancer cells. Barton developed a TAP-p53 mouse and embryonic stem cell line model, with tagged p53.

Barton discovered TRIM24, a previously unknown E3-ubiquitin ligase of p53, an epigenetic regulator over expressed in cancers. TRIM24 co-activates estrogen receptors and is a histone reader of a unique signature present at estrogen-regulated genes in breast cancer cells. Barton’s team is currently defining the impact of TRIM24, and other p53 regulatory proteins, on p53- functions in embryonic stem cells, and how p53-mediated regulation is temporally controlled during liver regeneration.

Breakthrough advances in treating breast cancer

Hortobagyi has authored more than 1,000 scientific articles advancing the field of breast cancer and is credited with leading pioneering advances in treating the disease, including combination chemotherapies for inoperable tumors, and multidisciplinary care for patients at all disease stages.

Early in his career, Hortobagyi conducted an innovative study that gave chemotherapy before surgery to breast cancer patients with locally advanced tumors that had not spread to other parts of the body. The study concluded that most large tumors could be reduced by at least 50 percent with the preoperative chemotherapy and then removed surgically. He also:

• Headed a 10- year study that showed a threedrug regimen admini s tered before surgery and radiation therapy after surgery, produced promising results for breast cancer patients with advanced disease. This approach was later applied with increased success to earlier stage disease.

• Led the clinical development of several drugs (anthracyclines and taxanes) in the breast cancer field

• Established the role of bisphosphonates to treat patients with bone metastases from breast cancer