Wnt defeats death

To be successful, a tumorigenic cell must not only multiply but also fail to die. You et al. report that Wnt-1 contributes to both sides of this equation. Wnt-1 cooperates with Myc in promoting cell division, and blocks Myc's propensity to cause apoptotic cell death (page 429).

As a tumor promoter, Myc's apoptosis-promoting properties were paradoxical. Now, You et al. find that autocrine or paracrine coexpression of Wnt-1 with Myc prevents this apoptosis. Two Wnt-1 targets—WISP-1 and the cyclooxygenase Cox2—were induced in these cells. They can act together, and independently of Wnt-1, to reduce apoptosis sharply.Cells expressing Myc alone formed small tumors with many apoptotic cells, whereas cells coexpressing Myc and Wnt-1 formed large tumors. This may explain the coincidence of mutations in the Myc and Wnt pathways in many...