Wnt Signaling as a Therapeutic Target in Cancer and Metastasis

NoWnt signaling normally functions in cell determination and proliferation and is essential for embryonic development. It does this by regulating target genes through a tightly regulated but complex signaling cascade. Overexpression of these genes due to aberrant Wnt activity can lead to uncontrolled cell growth and survival, and ultimately oncogenesis. Wnt signaling is also involved in epithelial–mesenchymal transition that contributes to tumor progression and metastasis evidence that tumor growth can be suppressed irrespective of other neoplastic promoters when the Wnt pathway is blocked and this has led to interest in its use as a therapeutic target. Recent developments in our understanding of the Wnt signaling cascade have led to research into drugs that specifically target different levels in this pathway, and the identification of β-catenin as the primary cause of dysregulated Wnt signaling has led to a number of protein knockdown strategies. Moreover, increased knowledge of the 300–400 Wnt inducible genes has provided a large untapped source of new potential therapeutic targets. Existing drugs such as nonsteroidal anti-inflammatory drugs and vitamin A and D derivatives have also shown efficacy in disrupting the Wnt signaling pathway and, together with a new generation of derivatives, they may soon be in clinical trials. This chapter details the Wnt signaling pathway, its role in different cancers, and some potential therapeutic targets that may show promise as effective cancer treatments