DNA甲基化介导Neuronatin沉默通过Ca2+相关信号通路促进肝癌侵袭转移的机制研究

Hepatocellular carcinoma (HCC) is one of the most malignant tumors with high morbidity in China. Metastasis and recurrence are considered the main leading causes of death for HCC. Accumulating evidence has demonstrated that epigenetic modifications especially DNA methylation plays an important role in initiation and progression of HCC. Neuronatin was primarily identified that its under-expression may be associated with methylation through screening for the human genome-wide microarray and its low expression and hypermethylation in HCC were confirmed by series of experiments. It was also demonstrated Neuronatin expression was closely correlated with cancer metastasis and patient prognosis. Further studies revealed that Neuronatin suppressed human hepatoma cells migration and invasion through elevating intracellular Ca2+ and relevant PKC/p38 MAPK signaling pathway. The project is proposed to make a further study including in vitro and in vivo models to clarify the function and the mechanisms of action of Neuronatin in HCC and the relationship between Neuronatin expression and promoter hypermethylation, and provide theory basis for the application of methylation in liver cancer early diagnosis , treatment and prognosis assessment.

肝癌是我国发病率较高的恶性肿瘤，转移和复发是导致肝癌高死亡率的主要原因，研究表明表观遗传学改变尤其是DNA甲基化在肝癌的发生发展过程中发挥了重要的作用。申请人前期通过人类全基因组表达谱芯片筛选到Neuronatin在肝癌中表达可能与甲基化相关，随后通过实验验证了Neuronatin在肝癌中的高甲基化和低表达，且组织标本检测表明Neuronatin与肝癌的转移和患者预后密切相关。体外实验证实了Neuronatin能够抑制肝癌细胞的迁移和侵袭，进一步探索其抑制肝癌侵袭转移的分子机制发现其可能是通过提高胞内Ca2+水平及相关的PKC/p38 MAPK信号通路发挥作用。本项目拟在此基础上结合体内、体外模型，多角度验证Neuronatin在肝癌侵袭转移中的作用及在肝癌中表达与甲基化调控的关系，阐明其在肝癌中发挥功能效应的具体分子机制，为甲基化在肝癌早期诊断、治疗及预后评估中的应用提供理论依据。

肝癌（Hepatocellular carcinoma）是世界范围内尤其是我国发病率较高的恶性肿瘤，转移和复发是导致肝癌患者死亡的主要原因。因此，对肝癌转移过程和机制的研究有助于加深对肝癌的了解和改善诊治水平。本课题通过免疫组化研究了肝癌组织芯片中Neuronatin的表达，发现Neuronatin在肝癌中的表达明显低于相应的癌旁组织，且其表达量与肝癌患者的肿瘤大小、血管侵袭、临床分期相关，与患者的总生存率正相关。进一步通过甲基化实验证实了Neuronatin启动子区CpG岛在肝癌中高甲基化。细胞功能实验和机制研究发现Neuronatin通过Ca2+相关信号通路抑制肝癌细胞的迁移和侵袭。本研究首次证明了Neuronatin在肝癌中的表达、作用和甲基化情况，为甲基化在肝癌早期诊断及预后评估中的应用提供了新的理论依据。