CDK5通过介导lncRNA-NONHSAT112116.1-HMGA1信号通路调控结直肠癌肿瘤干细胞形成和化疗耐药的机制研究

Failure of clinical chemotherapy caused by drug resistance increases the mortality of malignant tumor patients, whease extinct molecular mechanism of drug resistance has not been well described. Cancer stem cell (CSC) is a special cell type, which plays an important role in chemotherapeutic resistance . Our preivous study has described CDK5，a member of CDK family, as a novel oncogene in the development of colorectal cancer. Besides, we found that knocking down of CDK5 in colorectal cancer cells significantly decreased the formation of CSC. Also, silencing CDK5 results in a higher rate of apoptosis after the treatment of oxaliplatin on CSC. Furthermore, lncRNA microarray study shows that CDK5 can modulate the expression of a novel lncRNA NONHSAT112116.1 and its target gene: HMGA1, indicating that CDK5 may promote the chemoresistance of CSC via acting as an upstream factor of the NONHSAT112116.1-HMGA1 signaling pathway. In the present study, we will use both in vitro and vivo experiments to explore the extinct mechanism of CDK5-NONHSAT112116.1-HMGA1 and its role in modulating the stemness and chemoresistance of CSC. The relationship of CDK5-NONHSAT112116.1-HMGA1 pathway and its infect in prognosis of patients suffering chemotherapy will be assessed accoriding to the clinical data. Outcomes of this research may provide certain novel approach for clinical chemotherapeutic resistance of colorectal cancer.

耐药是导致恶性肿瘤化学治疗失效而死亡率升高的重要原因，但耐药的分子机制尚未深入认识。肿瘤干细胞（CSC）作为一类特殊的细胞群，在化疗耐药过程中扮演重要角色。CDK5是CDK家族的一员，我们在前期研究证明其能够促进结直肠癌的恶性演变。进一步预实验发现，沉默CDK5导致结直肠癌CSC形成减少；缺失CDK5的CSC在奥沙利铂刺激下凋亡率显著增加。基因组学表明CDK5可以调控lncRNA NONHSAT112116.1及其靶基因HMGA1的表达，提示CDK5可能通过调控NONHSAT112116.1-HMGA1信号通路发挥在CSC形成及耐药等特性的作用。本研究拟采用体内外实验详细探讨CDK5-NONHSAT112116.1-HMGA1通路互作机制及在CSC形成和耐药过程中的作用；结合临床资料评估该通路临床相关性及与化疗患者临床生存预后的关系。本项目的顺利实施有望为结直肠癌化疗耐药提供新的科学依据。

耐药是导致恶性肿瘤化学治疗失效而死亡率升高的重要原因，但耐药的分子机制尚未深入认识。肿瘤干细胞（CSC）作为一类特殊的细胞群，在化疗耐药过程中扮演重要角色。CDK5是CDK家族的一员，我们在前期研究证明其能够促进结直肠癌的恶性演变。进一步预实验发现，沉默CDK5导致结直肠癌CSC形成减少；缺失CDK5的CSC在奥沙利铂刺激下凋亡率显著增加。基因组学表明CDK5可以调控lncRNA NONHSAT112116.1及其靶基因HMGA1的表达，提示CDK5可能通过调控NONHSAT112116.1-HMGA1信号通路发挥在CSC形成及耐药等特性的作用。本项目通过系列体外结合体内实验，如CLIP验证了Hur与NONHSAT112116.1存在相互结合，而这一结合受到CDK5的磷酸化调控。荧光素酶报告基因发现NONHSAT112116.1可通过与Mir-195结合调控HMGA1的表达。肿瘤干细胞成瘤、增殖、凋亡、耐药等体外实验联合体内实验证实CDK5-NONHSAT112116.1信号通路能够正向促进CSC的生存及耐药特性。临床资料分析显示CDK5/NONHSAT112116.1高表达的患者存在更差的预后，揭示了CDK5/NONHSAT112116.1信号通路可作为结直肠癌患者预后的新型指标。本项目的顺利实施有望为结直肠癌化疗耐药和新型分子靶点的发现提供新的科学依据。