Windorphen is a Wnt inhibitor that selectively abrogates the Wnt signaling for ventral development.
Wnt protein is a family of signaling proteins that interacts on the Wnt/β-Catenin pathways during embryotic development, cell proliferation, migration and adult tissue homeostasis.
In canonical Wnt/β-catenin reporter cell line STF293, Windorphen dose-dependently inhibits Wnt3a-inducible TOPFLASH-luciferase activity (IC50 of 1.5 mM). In human colon adenocarcinoma
SW480 cells with defective APC gene that constitutively activates Wnt signaling, 72 h treatment of Windorphen causes a wide spread apoptosis. 
In zebrafish embryos, Windorphen leads to apparent expansion of the dorsal markers (pax2.1) and marker of rhombomeres 3 and 5 at the six-somite stage (krox0). Windorphen selectively inhibits Wnt signaling in ventral and lateral regions of the 50% epiboly stage embryo (5.3 hpf). In addition, Windoprhen treatment rescues the telencephalon/eye phenotype in the mbl mutant zebrafish (i.e. a defective Axin1/β-catenin destruction complex causes abnormal activation of Wnt signaling and the loss of telencephalon and eyes.) 
1. Hao J, Ao A, Zhou L et al. Selective small molecule targeting β-catenin function discovered by in
vivo chemical genetic screen. Cell Rep. 2013 Sep 12;4(5):898-904.