The active ingredient in a drug currently being tested to treat rheumatoid arthritis might also one day serve as an effective means of treating one of the deadliest forms of breast cancer. Researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have demonstrated that inhibiting the activity of the protease enzyme known as TACE can deprive tumor cells of a key factor needed for their proliferation. TACE is strongly present in a form of breast cancer which responds poorly to current therapies.
"We have shown that inhibition of the TACE protease in breast cancer cells blocks the shedding of two critical growth factor proteins and results in an inhibition of a key signaling pathway that controls cell division," said Paraic Kenny, a post-doctoral cell biologist with the research group of Mina Bissell in Berkeley Lab's Life Sciences Division. "Based on analysis of cells grown in three-dimensional cultures, the inhibition of this protease results in the reversion of the malignant phenotype of these breast cancer cells and switches their behavior back to a phenotype very reminiscent of non-malignant breast epithelial cells."
Kenny is the co-author along with Bissell of a paper published in the Journal of Clinical Investigation entitled: Targeting TACE-Dependent EGFR-ligand Shedding in Breast Cancer. This paper presents the latest experimental results from an on-going investigation led by Bissell into the ecology of tumors.
It has long been Bissell's contention that "no tumor is an island." Tumor cells, she maintains, exist in the same microenvironment as healthy cells and must therefore appropriate normal physiological processes to facilitate their growth and spread. As she and her colleagues have repeatedly demonstrated, this idea can open up potential new avenues and targets for diagnostic and therapeutic applications.