Previous studies at the University of Colorado Cancer Center show that the experimental drug AMPI-109 potently kills triple-negative breast cancer cells. But even the most compelling evidence of cell death in a dish isn’t enough to push a drug into human clinical trials, even for triple-negative breast cancer, which has a high mortality rate and remains largely without targeted treatment options.
Clinical trials are commonly guided by the knowledge of how a drug works – an understanding that can allow researchers to tweak a drug’s effectiveness or explore rational combinations of multiple drugs to maximize antitumor responses. Now a study published in the journal Oncogenesis offers compelling evidence that AMPI-109 works by flipping the switch on an enzyme called PRL-3 that initially puts cancer cells to “sleep” or senescence, and shortly thereafter leads to their death, or apoptosis.
“For decades, we’ve known about a paradoxical signaling pathway called TNF-R1 whose activation can either help a cell survive or lead to cell death. However, the signals that lead to this pathway promoting survival or promoting death have been poorly understood, especially in the context of cancer cells. We have observed that one regulator of this process in triple-negative breast cancer cells may be the activity of PRL-3. With this gene active, cells survive. With PRL-3 inactivated, cells senesce and eventually die,” says Hamid Gari, PhD, who studied the mechanism of PRL-3 while working as a doctoral candidate in the lab of CU Cancer Center investigator James R. Lambert, PhD. Gari is first author and Lambert is senior author of the current study which was performed in collaboration with Scott Lucia, MD in the department of Pathology.