Antitumor Ribonucleases

Abstract

Ribonucleases are small basic proteins that have shown remarkable antitumor activity linked to their ability to destroy RNA. Therefore, they are a second line of cancer chemotherapeutics as they are not genotoxic. This chapter summarizes the main biochemical characteristics of these enzymes and the key factors responsible for their cytotoxic mechanism. Some of them are shared by most cytotoxins, but each RNase has particular cancer cell killing abilities. The effects on the cell cycle and the induced apoptosis mechanism are cell dependent. The knowledge obtained from the cytotoxic mechanism of natural cytotoxic RNases has been used to artificially engineer more potent and selective RNA-degrading enzymes. These approaches are also described. The chapter ends with a brief description of the results of the clinical trials performed with RNases