Antibody Inhibits Breast Cancer Growth in Mice

A monoclonal antibody has been shown to extend considerably the survival of mice with human breast-cancer tumors and to inhibit tumor metastasis to the lungs in the animals by more than 50%.

The antibody, called JAA-F11, targets a specific disaccharide, an antigen known as TF-Ag, which helps in the adhesion and spread of certain cancer cells. Whereas the antibody did not kill the cancer cells, it blocked stages of cancer-cell growth that allow the cells to attach to organ tissue, the study demonstrated. The study's findings were published in the November 2006 issue of the journal Neoplasia.

Mice with breast-cancer tumors that received the antibody had an average survival time of 72 days, compared to 57 days for the mice that did not receive JAA-F11, the study found. Furthermore, exposing cultures of tumor cells to the antibody suppressed cell growth by a statistically significant 16%.

Kate Rittenhouse-Olson, Ph.D., associate professor of clinical and laboratory sciences in the University at Buffalo School of Medicine and Biomedical Sciences (Buffalo, NY, USA), was the senior investigator of the study. "This antibody binds with a carbohydrate on the tumor cell surface that is involved in adhesion of the cell during the metastatic process,” said Dr. Rittenhouse-Olson. "Not only would drugs attached to the antibody JAA-F11 bind to the tumor cell surface to direct their cytotoxic effect, but the binding of the antibody itself would block the cell from metastasizing.”

The antibody was evaluated utilizing in vitro models of tumor cell growth in assays to determine its ability to damage or kill cells (cytotoxicity) in various models of cancer metastasis, and finally, in mice with metastatic breast cancer. "In addition to providing a survival advantage,” remarked Dr. Rittenhouse-Olson, "JAA-F11 immunotherapy reduced the metastatic tumor burden significantly, reflected by both a dramatic decline in the overall incidence of spontaneous metastasis to the lung--88% to 47%--and fewer macroscopic metastatic lesions.”

The investigators currently are determining if JAA-F11 could increase the effectiveness of existing cancer drugs, according to Dr. Rittenhouse-Olson, as well as evaluating the possibility of using the antibody as a vehicle for the targeted delivery of drugs to aid cancer diagnosis and therapy.



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