DNAJB1通过β-catenin影响结直肠肿瘤干细胞特征的机制研究

Metastasis and relapse is the greatest risk to the death of patients with colorectal cancers. Cancer stem cells are considered to be the engine for metastasis. Recently, heat shock protein 40 is emerging to be a new target to inhibit colorectal cancer stem cells (CRCSC). In our primary study, DNAJB1 was found to be geneticaly amplificated and high expressed in colorectal cancer tissue, which was significantly related to the nuclear level of β-catenin and the early metastasis and recuurence of patients. Also, in vitro and in vivo data showed that dependent on β-catenin, DNAJB1 could affect the stemness of colorectal cancer cells and the expression of CRCSC markers, and metastasis as well. For further understanding the more molecular details of the effect of DNAJB1 on the stemness of CRCSC, in this proposal, we will employ approaches including cell sorting, gene overexpression or silencing, cell invasiveness, Co-IP and tumorgenesis to explore how DNAJB1 can regulate the stability of β-catenin proteins and the stability-associated proteins in colorectal cancer stem cells or non-stem cancer cells.

转移复发是结直肠癌最主要的死亡原因，而肿瘤干细胞是转移复发的关键因素。近来发现，热休克蛋白40可影响结直肠肿瘤干细胞特征及成瘤性。我们的临床研究发现，热休克蛋白DNAJB1在结直肠癌组织中高表达，并与β-catenin的活化和肿瘤早复发显著正相关。体内外实验显示，DNAJB1可能通过影响β-catenin的稳定性，调节结直肠肿瘤干细胞标志物表达及干细胞行为；沉默DNAJB1可显著抑制肿瘤转移。据此，本项目拟通过细胞分选、外源基因表达或沉默、Co-IP、细胞侵袭、小鼠成瘤及转移模型等方法，了解DNAJB1对结直肠肿瘤干细胞特征的影响；并通过DNAJB1对β-catenin的磷酸化、泛素化及其膜定位相关蛋白的影响，及是否依赖于MRJ，了解其调控β-catenin稳定性的分子机制，为结直肠干细胞的靶向治疗提供新的理论基础。

我们前期研究发现，DNAJB1可能通过影响β-catenin的稳定性，调节结直肠肿瘤干细胞标志物表达及干细胞行为。本项目拟在我们前期重要发现的基础上，深入研究DNAJB1在结直肠癌发生发展、特别是在肿瘤干性方面所涉及的信号通路及相互作用分子，着重探讨DNAJB1与DVL2蛋白相互作用的分子机制。本项目不仅有助于阐明结直肠癌发生发展的分子基础，而且可能为结直肠癌的临床诊断和预后后判断提供分子标志物，同时可能为结直肠癌的基因治疗提供重要的分子靶点。