During the last few years we have seen fundamental changes in the way
scientists approach the identification and validation of new drug targets. These
novel strategies for target validation are expected to maximize the likelihood
of achieving target-selective inhibition with minimal in vivo side effects. For
example, by the use of small interfering RNAs (siRNAs) to down regulate
expression of known genes, a number of therapeutic targets have been validated
both in vitro and in vivo. The technologies developed to do this have not only
yielded a significant number of drug targets but have influenced our understanding
of gene function, the molecular mechanisms of diseases, and the
design of new therapeutic interventions. Specific gene and protein targets—on
which, for example, cancer cells depend—can now be identified, along with
the therapeutic agents directed against them. Several relevant examples that
have been validated, and some that have reached the clinic, are featured in
Volume 2, Emerging Molecular Drug Targets and Treatment Options, of
Target Discovery and Validation Reviews and Protocols.