lncRNA GAS5抑制胃癌转移机制的探讨

Stomach cancer is one of the most malignant cancers in China, but there are few effective biomarkers can be used for clinical diagnosis and treatment. Our previous studies found that lncRNA GAS5 was a tumor suppressor in stomach cancer, and p53 protein was in the presence of proteins bound by lncRNA GAS5. Lowered lncRNA GAS5 expression could cause reduced p53 protein level and decreased cell number in G1 phase in stomach cancer cell lines. So we speculate lncRNA GAS5 plays a tumor suppressor role in stomach cancer by binding to and regulating p53 protein. We will use RNA-pull down, RIP, Turnover to explore the mechanisms how lncRNA GAS5 regulating p53 protein in stomach cancer. Wound healing and Transwell will be used for studying the influence of lncRNA GAS5 on metastasis and invision, by regulating p53 protein. We will also investigate how important the role of p53 protein plays for lncRNA GAS5 to suppress stomach cancer development. Finally, we will demonstrate these effects and mechanisms on stomach cancer tissues and animal level. The study will illuminate the understanding of the mechanism of lncRNA GAS5 and p53 in stomach cancer, and lay a more solid foundation for the development of lncRNA GAS5-based anti-cancer strategy in stomach cancer.

胃癌是我国预后最差的肿瘤之一，迄今仍缺乏有效的诊疗靶标。我们前期研究发现lncRNA GAS5在胃癌中具有抑癌作用，与之结合的蛋白中有p53蛋白；下调lncRNA GAS5，胃癌细胞p53蛋白水平和G1期细胞比例随之下降。鉴于lncRNA GAS5和p53与肿瘤转移关系密切，故我们推测lncRNA GAS5可能通过结合并调控p53蛋白而抑制胃癌转移。为验证上述假说，本课题拟运用RNA-pull down、RIP、Turnover等技术探索lncRNA GAS5在胃癌中调控p53蛋白的机制，运用Wound healing和Transwell等技术研究lncRNA GAS5通过p53蛋白对胃癌细胞转移和侵袭的影响，并用免疫组化等技术在胃癌组织和动物水平加以验证。本研究预期能初步阐明lncRNA GAS5和p53抑制胃癌发生发展的机制，为研发以lncRNA GAS5为靶点的诊疗策略奠定基础。

胃癌是世界上第四常见的恶性肿瘤，也是导致癌症相关死亡率的第二大主要原因。尽管近年来胃癌的诊断和治疗策略有了很大的进展，但胃癌患者的5年总生存率仍低于30%，80%以上的胃癌患者诊断为晚期，多数伴有广泛浸润和远处转移，预后不佳。因此，寻找新的胃癌诊断和治疗靶点迫在眉睫。LncRNAs通过在转录、转录后和表观遗传学等不同水平上调节基因表达，参与多种生物学行为。它们通过不同的机制参与了生理和病理过程。GAS5的表达下调与胃癌细胞增殖密切相关，因此导致胃癌患者预后不佳。然而，GAS5在胃癌转移中是否发挥作用以及如何发挥作用尚不清楚。.我们的研究通过原位杂交、转染、RT-PCR、Western Blot、RNA-pull down、RIP、转移、侵袭、Turnover等实验证实GAS5能够在mRNA和蛋白水平正向调控p53的表达，而且GAS5与p53蛋白能够直接相互作用，在胃癌组织中p53表达与GAS5水平呈正相关。本研究还揭示，GAS5通过其依赖于12号外显子延长p53蛋白的半衰期，12号外显子被认为是GAS5与蛋白质结合的关键。最后，我们发现GAS5通过p53信号通路影响胃癌细胞的转移。总之，本研究阐明了GAS5通过p53依赖的途径通过抑制胃癌转移而发挥抑癌作用，提示特别是对于那些远处转移的胃癌患者来说，GAS5有可能作为治疗的潜在靶点。