HBx-UPF1-snoRNAs通路在肝癌发生发展中的作用机制研究

Tumor invasion and metastasis are responsible for the poor prognosis of hepatocellular carcinoma (HCC). However, the underlying mechanism remains elusive. Our preliminary data showed that the expression of UPF1 in HCC was decreased and significantly correlated with vascular invasion (PVTT), BCLC stage and poor prognosis. RIP-seq analysis and in vitro/vivo assays indicated that UPF1 could combine with snoRNAs and UPF1 overexpression represses invasion and migration of hepatoma cells. Furthermore, UPF1 expression was modulated by HBx. Collectively, we assume that HBx-UPF1-snoRNAs axis regulates the cell invasion and metastasis in HCC . In this study, we aim to determine the expression of UPF1 and HBx and the relevant clinical significance in HCC, to disclose the epigenetical regulation mechanisms of UPF1 and the effect of HBx on UPF1, to unveil the mechanism of UPF1-mediated regulation of snoRNAs expression, and to reveal the role of HBx-UPF1-snoRNAs signaling pathway in cell invasion and metastasis in HCC, using a series of biological and immunological experiments in cell and animal models. Our study is likely to provide not only solid evidence that UPF1 is involved in HCC progression, but also a promising therapeutic target in HCC.

侵袭转移是导致肝细胞癌预后差的主要因素，但其分子机制尚未明了。我们前期研究发现UPF1在肝癌细胞及组织中低表达，并与血管侵犯、肿瘤分期及预后差密切相关；RNA免疫共沉淀测序及体内外实验表明UPF1靶向snoRNAs，过表达UPF1显著抑制肝癌的侵袭转移；此外，UPF1表达受HBx调控。因此，我们提出HBx-UPF1-snoRNAs轴调控肝癌侵袭转移的假说。本项目拟采用一系列分子细胞生物学和免疫学实验，利用多种细胞株和动物模型，在细胞功能及蛋白表达调控上，明确UPF1和HBx在肝癌中的表达及临床意义，揭示UPF1表达调控的表观遗传机制及HBx调控UPF1的作用机理，探讨UPF1对snoRNAs的调控作用，阐述HBx-UPF1-snoRNAs通路在肝癌侵袭转移中的作用及其分子机制，从而获得UPF1参与肝癌恶性进程的可靠证据，为寻找肝癌治疗新靶点和诠释肝癌发生发展的分子机制提供科学依据。

侵袭转移是导致肝细胞癌预后差的主要因素，但其分子机制尚未明了。我们前期研究成果证实上游移码因子（Upf1）在原发性肝细胞癌（HCC）中发挥抑癌基因的作用， Upf1在HCC中低表达，并与血管侵犯、肿瘤分期及预后差密切相关，过表达Upf1显著抑制肝癌的侵袭转移；RNA 免疫共沉淀测序及体内外实验表明Upf1靶向小核仁RNAs（snoRNAs）具体分子不详。本项目采用RNA高通量测序联合一系列分子细胞生物学及免疫学实验，利用多种细胞株和动物模型，在细胞功能及蛋白表达调控上，明确了Upf1和小核仁RNA 52（SNORD52）在HCC中的表达及临床意义，证实了SNORD52是受Upf1调控的下游靶标基因。SNORD52在HCC中表达明显升高，且SNORD52的表达与HCC患者临床病理参数及预后明显相关。体内外实验证实SNORD52促进HCC的生长，增殖等一系列肿瘤生物学行为的改变。RNA-pulldown，RIP及Co-IP等实验明确SNORD52通过结合并稳定周期蛋白依赖性激酶1（CDK1），增强CDK1磷酸化及与细胞周期蛋白B1（CyclinB1）的结合，诱导细胞周期G2/M转变，最终促进HCC的发生、发展。SNORD52发挥促癌作用在一定程度上依赖CDK1。以上研究结果表明Upf1/SNORD52/CDK1轴在HCC进程中发挥重要作用。上述分子轴为HCC的治疗提供新的治疗新靶点和诠释HCC侵袭转移的分子机制提供新的科学依据。