DKC1调控口腔鳞癌程序性细胞死亡的分子机制及其临床意义研究

Programmed cell death (PCD) is death carried out in a regulated process, including apoptosis and necroptosis, which was recently coined and seen as programmed necrosis. PCD could eliminate the cells with precarious or incomplete genome under normal physiological conditions, so as to resist tumorigenesis to some extent. Otherwise, it is a frontier and important study to activate programmed cell death pathway in molecular targeted therapy for tumors. DKC1 plays core role in telomerase functions and is very important for genome integrity and stability. In previous studies, we found that depletion of DKC1 would result in telomere shortening, DNA damages increasing. However, it was unclear whether the status would promote tumorigenesis, as well whether the programmed cell death process would be implicated in. Based on the previous studies, we intend to do some further research in Oral Squamous Cell Carcinoma (OSCC) cells. Firstly, we need to identify the function of DKC1 in tumorigenesis and development of OSCC using the clinical tissue samples, cell experiments and animal xenografts. Moreover, we want to uncover the relationship between DKC1 depletion and apoptosis through testing the difference of key proteins associated with apoptosis process. Thirdly, necroptosis model would be induced using OSCC cells, then some proteins which are identified as activation marker for necroptosis will be test. And we will determine the potential function of DKC1 in regulating necroptosis using several experiments for full validation. All what we will do in this project are just supposed to investigate the potential function of DKC1 and the detail molecular mechanism in the process of apoptosis or necroptosis, which might uncover a new way in early diagnosis and targeted therapy for OSCC.

程序性细胞死亡(PCD)包括细胞凋亡与新近备受关注的细胞程序性坏死，具有清除基因组不稳定细胞，防止细胞癌变的生理意义，此外，如何诱导肿瘤细胞进入PCD途径，是目前肿瘤靶向防治的前沿。先天性角化不良基因DKC1参与端粒酶功能执行，维护细胞基因组的完整和稳定；申请人前期发现DKC1缺失导致端粒缩短、DNA损伤增多；然而，是否会导致肿瘤发生，以及PCD是否参与此过程，尚未见报道。基于此，申请人以口腔鳞癌OSCC为模型，拟①从病例组织、细胞、动物水平多角度验证DKC1与OSCC发生发展的关系；②通过凋亡相关蛋白表达水平的变化,探讨DKC1与细胞凋亡的关系；③构建OSCC程序性坏死模型，检测其调控过程中关键蛋白的表达差异，多种实验手段充分研究DKC1与程序性坏死的关系。通过本研究阐释DKC1在口腔黏膜上皮细胞癌变中的潜在功能，探讨其对PCD的分子调控机制，为OSCC的早期预防和靶向治疗提供新思路。

有效的早期分子诊断和高效的分子靶向治疗是未来降低口腔癌发病率、提高治愈率的重要研究内容。本项目旨在论证和评估DKC1作为口腔癌早期预防和分子治疗靶点的可行性和潜在应用价值。通过基于大数据的生物信息学统计和分析、OSCC细胞模型的构建和体外实验验证、小鼠移植瘤模型的构建及体内验证以及对其分子信号通路调控机制的研究，我们发现DKC1在OSCC病人中的表达水平显著高于正常人群，且其表达越高的OSCC病人的生存预期越差。体外细胞水平以及小鼠体内的实验数据显示，DKC1缺失会显著抑制OSCC细胞的增殖能力。进一步，通过全方位、多角度的分子调控通路研究，我们发现DKC1缺失会引起OSCC细胞内DNA损伤积累的显著增多，且会影响细胞周期的变化，并显著提升OSCC细胞对DNA复制类抑制剂喜树碱的药物敏感性，进而促进细胞凋亡。然而，DKC1缺失却在短时间内不会引起端粒长度的变化，也不会显著促进细胞程序性坏死。综上所述，我们认为DKC1在OSCC的早期发生和后期发展过程中发挥了重要的作用，因此，DKC1是OSCC早期诊断和后期治疗的重要潜在靶点，具有重要的潜在临床应用价值和意义。