DDA1基因调控NF-κB在结肠癌发生发展中的作用及机制研究

Identification and functional analysis of novel potential cancer-associated genes is of great importance for developing diagnostic, preventive and therapeutic strategies for cancer treatment and management. DDA1 gene was first cloned by our group. Currently, little is known about DDA1 gene function, especially its role in tumor. Our previous study demonstrated that DDA1 was overexpressed in colorectal cancer tissue, and strongly associated with poor overall survival. Silencing of DDA1 expression could significantly inhibit colon cancer growth both in vitro and in vivo. Preliminary study on DDA1 gene function revealed that inhibition of DDA1 expression could significantly suppress the activation of NF-κB transcription factor and expression of its downstream targeted genes in colon cancer cells. Those result indicated that the DDA1 may involved in constitutive activation of NF-κB signaling. However, the underlie mechanism is unknown. In this project, we aim to elucidate the molecular mechanism of DDA1 in activation of NF-κB and its role in tumor cell both in intro and in vivo. We hope that this project could help us to better understand the biological function of DDA1 and provide a novel candidate for tumor targeted therapy.

发现和鉴定新的肿瘤相关基因对于开发新的肿瘤诊断、预防和治疗策略具有重要意义。DDA1基因是本课题组首先克隆获得的新基因。目前DDA1基因功能还知之甚少，尤其是在肿瘤中的作用尚未见报道。本课题组前期研究发现DDA1在结肠癌肿瘤组织中高表达并且与结肠癌病人不良预后相关。抑制DDA1表达能显著抑制结肠癌细胞在体内和体外的生长。对DDA1基因功能初步研究发现，在结肠癌细胞中抑制DDA1表达能显著抑制NF-κB转录因子的激活以及下调NF-κB下游靶基因的表达。以上结果表明在结肠癌中DDA1参与调控NF-κB组成性激活信号通路，但是其作用机理不清楚。因此，本课题将综合利用裸鼠皮下移植瘤模型，组织芯片，免疫共沉淀联合质谱等技术，阐明DDA1基因调控NF-κB信号通路的分子机理及其在结肠癌发生发展中的作用，为深入理解DDA1在肿瘤中的生物学功能奠定基础，为未来设计抗肿瘤治疗提供候选靶点。

发现和鉴定新的肿瘤相关基因对于开发新的肿瘤诊断、预防和治疗策略具有重要意义。DDA1基因是本课题组首先克隆获得的新基因。目前对于DDA1基因的功能还知之甚少，尤其是在肿瘤发生发展中的作用。课题研究者利用CRISPR-Cas9技术构建了DDA1敲除的结肠癌细胞株。运用相关的细胞功能学实验发现在体外DDA1敲除可以抑制肿瘤细胞的增殖侵袭和迁移能力。利用裸鼠皮下移植瘤模型实验，我们发现DDA1敲除可以抑制裸鼠皮下移植瘤的生长。在探索DDA1调控肿瘤细胞生物学功能分子机制时，我们发现p53可以调控DDA1的表达。相关的分子实验证明DDA1是p53下游的调控基因。通过免疫共沉淀联合质谱技术我们发现p53与DDA1存在蛋白水平上的直接相互作用。在探究DDA1下游调控的靶基因时，我们发现抑制DDA1表达能显著抑制NF-κB转录因子的激活以及下调NF-κB下游靶基因的表达。我们阐明了DDA1上游和下游的调控分子，为深入理解DDA1在肿瘤中的生物学功能奠定基础，为结肠癌及其他恶性肿瘤的治疗提供新的思路。