CDC25 phosphatases in cancer cells: key players? Good targets?

Cell division cycle 25 (CDC25) phosphatases regulate key transitions between cell cycle phases during normal cell division, and in the event of DNA damage they are key targets of the checkpoint machinery that ensures genetic stability. Taking only this into consideration, it is not surprising that CDC25 overexpression has been reported in a significant number of human cancers. However, in light of the significant body of evidence detailing the stringent complexity with which CDC25 activities are regulated, the significance of CDC25 overexpression in a subset of cancers and its association with poor prognosis are proving difficult to assess. We will focus on the roles of CDC25 phosphatases in both normal and abnormal cell proliferation, provide a critical assessment of the current data on CDC25 overexpression in cancer, and discuss both current and future therapeutic strategies for targeting CDC25 activity in cancer treatment.

Small molecule regulation of phosphatase-dependent cell signaling pathways.

Small molecules provide exceptionally useful tools for probing signaling targets relevant for cancer and stem cell differentiation. In contrast to genetic approaches, the application of small molecules generally offers a graded and reversible disruption of a particular pathway. The vast array of theoretical chemical entities that exist in the chemical universe are now becoming available through the production and distribution of chemical libraries generated by both traditional and combinatorial methods, which are suitable for pharmacological use. Convenient and inexpensive cell-free and cell-based assays can be used to identify chemicals that exhibit desirable antisignaling properties. We illustrate a model of how agents targeted against signaling macromolecules involved in cancer, namely dual specificity protein phosphatases, can be identified.