Secreted Wnt ligands play a major role in the development and progression of many cancers by modulating signaling through cell-surface Frizzled receptors (FZDs). In order to achieve maximal effect on Wnt signaling by targeting the cell surface, we developed a synthetic antibody targeting six of the 10 human FZDs. We first identified an anti-FZD antagonist antibody (F2) with a specificity profile matching that of OMP-18R5, a monoclonal antibody that inhibits growth of many cancers by targeting FZD7, FZD1, FZD2, FZD5 and FZD8. We then used combinatorial antibody engineering by phage display to develop a variant antibody F2.A with specificity broadened to include FZD4. We confirmed that F2.A blocked binding of Wnt ligands, but not binding of Norrin, a ligand that also activates FZD4. Importantly, F2.A proved to be much more efficacious than either OMP-18R5 or F2 in inhibiting the growth of multiple RNF43-mutant pancreatic ductal adenocarcinoma cell lines, including patient-derived cells.

分泌的Wnt配体通过调节细胞表面卷曲蛋白受体（FZDs）的信号传导在许多癌症的发生和发展中起主要作用。为了通过靶向细胞表面实现对Wnt信号的最大作用，我们开发了一种针对10个人FZD中的6种的合成抗体。我们首先鉴定了一种抗FZD拮抗剂抗体（F2），其特异性谱与OMP-18R5相匹配，OMP-18R5是通过靶向FZD7，FZD1，FZD2，FZD5和FZD8抑制许多癌症生长的单克隆抗体。然后，我们通过噬菌体展示技术使用了组合抗体工程技术来开发变异抗体F2.A，其特异性扩大到包括FZD4。我们确认F2.A阻止了Wnt配体的结合，但没有阻断Norrin（也激活FZD4的配体）的结合。重要的是，F2。RNF43突变的胰腺导管腺癌细胞系，包括患者来源的细胞。