CK1δ/ε介导的AES的降解调控结直肠癌转移和干性的机制研究

The Wnt signaling plays an important role in the initiation and development of colorectal cancer. Both CK1 and transcription regulation factor AES can regulate the Wnt signaling and are related to the initiation and development of colorectal cancer. However, there is no report on the crosstalking between these two proteins. Our previous studies showed that CK1δ/ε could interact with AES and promote AES degradation, and CK1δ/ε-AES regulated the transcription of Wnt target genes and the migration, invasion and stemness of colorectal cancer cells. In this proposal, we will first investigate the domain involved in CK1δ/ε and AES interaction and the site of AES phosphorylated by CK1δ/ε; then we will explore E3 ubiquitin ligase participating in CK1δ/ε-mediated AES degradation; further we will clarify the mechanisms by which CK1δ/ε-AES regulating the Wnt signaling to control the migration, invasion and stemness of colorectal cancer cells; finally, using several colorectal metastatic tumor models in mice, we will evaluate the effects of CK1δ/ε-AES and CK1 inhibitor on the metastasis and stemness of colorectal cancer. This study will reveal new mechanisms by which CK1-mediated AES degradation regulating the Wnt signaling to modulate the metastasis and stemness of colorectal cancer, and elucidate the efficacy of CK1 inhibitors on colorectal cancer, so as to open new ideas and approaches for the development of drugs against colorectal cancer in the future.

Wnt信号在结直肠癌的发生、发展中发挥重要作用。酪蛋白激酶CK1和转录调控因子AES都能参与调节Wnt信号且与结直肠癌的发生、发展相关，但两者间是否存在对话却未见报道。前期研究发现CK1δ/ε能与AES互作并促进AES降解；且CK1δ/ε-AES能调节Wnt靶基因转录和结直肠癌细胞的迁移、浸润及干性。本研究首先将确定CK1δ/ε和AES互作的结构域及CK1δ/ε磷酸化AES的位点；探索参与CK1δ/ε介导的AES降解的E3泛素连接酶；进而阐明CK1δ/ε-AES调节Wnt信号来调控结直肠癌细胞的迁移、浸润及干性的机制；最后将利用多种结直肠癌小鼠转移瘤模型，评价CK1δ/ε-AES和CK1抑制剂对结直肠癌转移及干性的作用。本研究将揭示CK1介导的AES降解调节Wnt信号来调控结直肠癌转移及干性的新机制，同时将阐明CK1抑制剂对结直肠癌的疗效，为今后开发治疗结直肠癌的药物提供新的思路和途径。

Wnt信号在结直肠癌的发生、发展中发挥重要作用，然而，目前还没有靶向Wnt信号的药物在临床用于肿瘤治疗，究其原因，可能是调控Wnt信号的机制还不甚明了。在本项目的资助下，我们研究发现酪蛋白激酶CK1δ/ε能磷酸化转录调控因子AES的Ser121，促进磷酸化的AES与E3连接酶SKP2相互作用，泛素化并降解AES，从而激活Wnt信号。这一分子机制在结直肠癌细胞迁移、浸润、干性维持以及结直肠癌类器官生长中发挥重要作用；也在结直肠癌肝转移小鼠模型中发挥关键作用。CK1抑制剂也能抑制结直肠癌类器官的生长和结直肠癌PDX小鼠模型的肿瘤生长。这一研究，揭示了CK1δ/ε介导的AES降解促进Wnt信号调控结直肠癌转移及干性的新机制，也评价了CK1抑制剂治疗结直肠癌的疗效，为今后开发CK1抑制剂抗肿瘤提供了理论基础。.此外，利用该项目资助，我们发现了肿瘤干细胞抑制剂盐霉素在结直肠癌细胞中能阻断Wnt信号转录激活因子β-catenin和转录因子TCF4的相互作用，抑制Wnt信号，阻止肿瘤干细胞的成瘤能力，从而有效地抑制结直肠癌的发生、发展。.总之，在该项目的资助下，我们的研究成果为Wnt信号抑制剂的研发提供了理论基础和思路。该项目培养博士后2人，研究生3人，并在Theranostics、Br J Pharmacol、Pharmacol Res、Cell Death Dis等杂志发表了6篇SCI研究论文。