The Wnt signaling pathways play fundamental roles during both development and adult homeostasis. Aberrant activation of the canonical Wnt signal transduction pathway is involved in many diseases including cancer, and is especially implicated in the development and progression of colorectal cancer. Although extensively studied, new genes, mechanisms and regulatory modulators involved in Wnt signaling activation or silencing are still being discovered. Here we applied a genome-scale CRISPR-Cas9 knockout (KO) screen based on Wnt signaling induced cell survival to reveal new inhibitors of the oncogenic, canonical Wnt pathway. We have identified several potential Wnt signaling inhibitors and have characterized the effects of the initiation factor DExH-box protein 29 (DHX29) on the Wnt cascade. We show that KO of DHX29 activates the Wnt pathway leading to upregulation of the Wnt target gene cyclin-D1, while overexpression of DHX29 inhibits the pathway. Together, our data indicate that DHX29 may function as a new canonical Wnt signaling tumor suppressor and demonstrates that this screening approach can be used as a strategy for rapid identification of novel Wnt signaling modulators.

Wnt 信号通路在发育和成人体内平衡过程中发挥着重要作用。经典 Wnt 信号转导通路的异常激活涉及包括癌症在内的许多疾病，尤其与结直肠癌的发展和进展有关。尽管进行了广泛研究，但仍在发现参与 Wnt 信号激活或沉默的新基因、机制和调节剂。在这里，我们应用了基于 Wnt 信号诱导细胞存活的基因组规模 CRISPR-Cas9 敲除 (KO) 筛选，以揭示致癌、经典 Wnt 途径的新抑制剂。我们已经确定了几种潜在的 Wnt 信号抑制剂，并表征了起始因子 DExH-box 蛋白 29 (DHX29) 对 Wnt 级联的影响。我们表明 DHX29 的 KO 激活了 Wnt 通路，导致 Wnt 靶基因细胞周期蛋白-D1 的上调，而 DHX29 的过表达抑制了该通路。总之，我们的数据表明 DHX29 可以作为一种新的经典 Wnt 信号肿瘤抑制因子，并证明这种筛选方法可用作快速识别新型 Wnt 信号传导调节剂的策略。