Project 4
"Synthetic Lethality - reversing therapeutic resistance"
Principal Investigators:
Paul Yaswen, LBNL, Life Sciences Division
Rene Bernards, Netherlands Cancer Institute, The Netherlands
Therapeutic resistance to specific inhibitors of the Raf-MEK-ERK pathway is likely to be mediated by a variety of genetic and epigenetic events that influence up- and down-stream elements of the Raf-MEK-ERK pathway itself, as well as cooperating pathways involved in drug transport, growth, and apoptosis. While some of these elements are already known, and can be used immediately for predictive modeling, the identification of additional pathway elements and characterization of their functional susceptibilities will increase the accuracy of the models developed. In addition, identification of these elements should provide new predictive markers, therapeutic targets and/or a rational framework for the design of combinatorial therapies.
We are taking a functionally directed approach to the identification of genes whose products influence cellular susceptibility to individual therapeutic agents and pathway inhibitors. This approach employs the relatively new RNA interference (RNAi) technology in positive and negative selection assays for growth in the presence of specific agents. RNAi provides a way to manipulate the expression of genes in a dominant, highly specific manner. A large library of retroviral vectors encoding short hairpin (sh)RNAs has been constructed in one of our laboratories (R. Bernards), and can be efficiently transduced into genetically identical host cells for selection assays. The advantage of this approach is that, unlike correlative approaches in which the relevance of identified genes must be further ascertained by individual testing and annotation, the relevance of the identified genes to the acquired phenotype is determined right from the start, using the power of genetics.