Sensitized RNAi screen of human kinases and phosphatases identifies new regulators of apoptosis and chemoresistance.

Evasion from apoptosis is a hallmark of cancer, and recent success using targeted therapeutics underscores the importance of identifying anti-apoptotic survival pathways. Here we utilize RNA interference (RNAi) to systematically screen the kinase and phosphatase component of the human genome. In addition to known kinases, we identified several new survival kinases. Interestingly, numerous phosphatases and associated regulatory subunits contribute to cell survival, revealing a previously unrecognized general role for phosphatases as negative regulators of apoptosis. We also identified a subset of phosphatases with tumour-suppressor-like activity. Finally, RNAi targeting of specific protein kinases sensitizes resistant cells to chemotherapeutic agents. The development of inhibitors that target these kinases or phosphatases may lead to new anti-cancer strategies.