Dr. Hong Sun secures federal funding to

study new targets in breast cancer research

Nevada Cancer Institute (NVCI) researcher Hong Sun, M.D., Ph.D., received notification from the Department of Defense (DOD) that she will receive a grant of $675,000 to study a new therapeutic approach to breast cancer based on Dr. Sun’s ongoing work on the IGF-I receptor protein.

Breast cancer occurs at a rate of nearly 200,000 new cases a year in the United States, resulting in about 40,000 breast cancer deaths per year. In Nevada, breast cancer is the most common form of cancer in women. It is estimated that there will be 1,270 new cases of breast cancer diagnosed in Nevada in 2008 and that approximately 340 of these women may die in 2008. Finding an effective treatment for breast cancer is a major challenge facing the scientific and healthcare community.

“This DOD grant will allow us to push forward our breast cancer research program and test a novel strategy for effective treatment of breast cancer,” said Dr. Sun, NVCI director of Cancer Genomics, Division of Basic Science.

The grant was rated as an “outstanding proposal from an accomplished investigator who proposes an innovative concept that has high translational potential for new approaches in breast cancer therapy.” In fact on a scale of one to 10, one being low merit and 10 being high merit, Dr. Sun’s proposal received a 9.9 score in terms of scientific impact in the breast cancer field.

“This is a highly competitive funding source and Dr Sun’s proposal received extremely high marks from the reviewers,” said David C. Ward, Ph.D., NVCI deputy director. “This illustrates once again that NVCI research programs are well-regarded by our peers and are highly competitive at the national level.”

Advanced breast cancer is normally treated with cancer-killing drugs, called chemotherapy. However, the success of chemotherapy is hampered by the resistance of cancer cells to such drugs, which leads to tumor recurrence, spread (metastasis) and cancer death. Therefore, enhancing the sensitivity of tumor cells to these cancer-killing agents is a major goal of breast cancer researchers. Dr. Sun’s research is aimed at testing a novel strategy for enhancement of treatment effectiveness for breast cancer.

Cell signaling is the process by which cells receive signals from the environment which instruct the cells when to grow, when to rest and when to become specialized cells. One type of cell signaling, IGF-I (insulin-like growth factor I) receptor signaling, plays a critical role in regulating cell proliferation and survival, as well as tumor development and progression. Recently the IGF-I receptor has been recognized as a molecular target for anti-cancer therapy. Both the research community and pharmaceutical companies are actively developing anti-cancer drugs that work by inhibiting signaling by the IGF-I receptor.

Dr. Sun and her laboratory have made a novel discovery that the IGF-I receptor needs to be localized in specific places within the cells’ outer membrane in order for it to function. Just like a ZIP code is required for delivery of post mails, the IGF-I receptor needs “an address” to be localized in its proper region for functioning. Dr. Sun has recently identified the ZIP code/address for the IGF-I receptor at the cell surface.

When the proper localization of the IGF-I receptor is inhibited, it leads to powerful inhibition of tumor cell growth and causes tumor cell death in cultured human cancer cells. Dr. Sun proposes to use preclinical models to test whether her methods for preventing proper localization of the receptor will cause breast cancer tumors to shrink. If successful, this may lead to rapid translation of the research findings for clinical use in breast cancer treatment.