Misleading tumor cells

DNA-damaging agents such as cisplatins are widely used in cancer treatment but have a narrow therapeutic window: too low a dose allows for DNA repair, and too high a dose is widely cytotoxic. Researchers at Novartis AG now report that a compound that inhibits the mTOR pathway works as an adjuvant by sensitizing treated cells to apoptosis, thus potentially increasing the therapeutic window for cytotoxic drugs like cisplatin. The compound also is being tested as a stand-alone therapy for cancer.

Cisplatin damages DNA, thereby triggering DNA surveillance mechanisms. Minor damage induces cell cycle progression inhibitors such as p21, which in turn initiate repair programs. If the damage is irreversible, however, the cells are sent into apoptosis via p53 expression...