Why some tumors withstand treatment -- kinase inhibitors

ScienceDaily
 
Bypass system
Kinase inhibitors, frequently used against breast, ovarian, and other cancers, work by disrupting cell signaling pathways that stimulate cells to grow, proliferate, or become invasive. Doctors usually prescribe them based on whether a patient's tumor is overexpressing a cancer-driving protein such as epithelial growth factor receptor (EGFR).
However, these drugs can fail even in tumors where they should work. About half of these failures are caused by genetic mutations that allow cancer cells to evade the drug's actions, but the rest are unexplained, Lauffenburger says.
Based on their previous studies of endometriosis (when uterine tissue grows into surrounding organs), Lauffenburger and his colleagues suspected there could be a backup pathway helping cancer cells to sidestep the effects of kinase inhibitors. In those studies, the researchers found that invasive endometrial cells become "addicted" to a certain growth signal, and that this pathway actually shuts off other growth pathways. Drugs that shut down the primary pathway can have the unintended effect of activating those backup systems.
The MIT team wondered if the same thing might be happening in cancer cells......