LOX在肝癌肿瘤起始细胞中的分子机制和功能特征

The discovery and emergence of researching on tumor initiating cells (TICs) is a revolution on liver cancer occurrence, development and evolution of treatment. Recurrence of liver cancer is closely related to the mechanisms of transition from non-TICs to TICs. Lysyl oxidase (LOX) is important protein in the evolution from liver cirrhosis to cancer and also involved in the migration of liver cancer cells by regulation of micro-environmental through ECM signal transduction. So it is an accomplice of the hepatic cancer metastasis. Previous work was based on a monoclonal antibody against recurrent hepatocellular carcinoma (HCC), 1B50-1, which bound the calcium channel α2δ1 subunit (isoform 5) and identified a subset of TICs with stem cell-like properties. Recently，we found that expression of LOX was positive relevant to α2δ1, and both of them were regulated by miRNA 200b. Sphere formation assays were performed to determine that LOX contributes self-renewal capacity of non-TIC cell Hep-11 in vitro. These data indicated LOX was related to TIC of liver cancer. In this research，we focus on the effect of LOX on tumor growth, invasion, metastasis, drug resistance of HCC cell lines and cases of clinical patient derived tumor xenograft (PDTX) models. Furthermore, we confirm whether LOX might be as a prognostic indicator for HCC and of new therapeutic targets by analysis the relationship between expression of LOX and pathological character in HCC specimens. Then, we determine the upstream and downstream regulation factors which regulate the expression level of LOX by gene chips and protein technologies. Last, we confirm which miRNA might target LOX and degrade LOX protein. Thus, we clarify weather LOX plays essential roles in TIC properties' maintenance. These studies might contribute to the understanding of HCC recurrence and matastasis at both the cellular and molecular levels and advance the development of prognostic and therapeutic strategies.

肿瘤起始细胞（TIC）的发现和兴起是研究肝癌发生、发展及治疗措施进化的一次革命。肝癌的复发之源与TIC转移机制有密切关系。其中赖氨酰氧化酶（LOX）是肝细胞变性-肝硬化-肝癌演进过程中的重要分子，参与肝癌的起源与微环境的调控，调节ECM信号转导，是肝癌细胞转移的帮凶。基于本组建立的一个识别肝癌肿瘤起始细胞的特异性抗体1B50-1，其能有效抑制肝癌的生长，同时发现LOX与其表达正相关，并共同受miRNA 200b的调控。因此本课题的研究从LOX调控肝癌起始细胞的致瘤、耐药、生长、侵袭、转移等特征出发，结合临床PDTX模型和病例标本，分析LOX联合化疗治疗效果，判断LOX是否能成为肝癌预后判断的指标及治疗的新靶点。利用芯片、蛋白技术，系统分析LOX上下游调控原件，探讨与肝癌临床特征的联系。整合miRNA技术，分析、解释肝癌发生及转移分子生物学机制。进一步为探索肝癌治疗的分子靶标提供有价值线索。

肿瘤起始细胞（TIC）是研究肝癌发生、发展及治疗措施是关键的研究事件。肝癌的复发之源与TIC转移机制有密切关系。其中赖氨酰氧化酶（LOX）是肝细胞变性-肝硬化-肝癌演进过程中的重要分子，参与肝癌的起源与微环境的调控，调节ECM信号转导，是肝癌细胞转移的帮凶。基于本组建立的一个识别肝癌肿瘤起始细胞的特异性抗体1B50-1，能有效抑制肝癌的生长，同时发现LOX与其表达正相关，因此，我们提出肝癌干细胞的维持是通过肿瘤干细胞分泌的LOX而伴随发生的假说。因此本课题的研究从LOX调控肝癌起始细胞的致瘤、耐药、生长、侵袭、转移等特征出发，结合临床PDTX模型和病例标本，分析LOX联合化疗治疗效果，判断LOX是否能成为肝癌预后判断的指标及治疗的新靶点。利用芯片、蛋白技术，系统分析LOX上下游调控原件。其中重要结果显示LOX 可以维持肝癌肿瘤干细胞的祖性，侵袭性和耐药性。并通过交联细胞外基质中的胶原，激活了肿瘤表面整合素A7， 特异性的启动了FAK的磷酸化和ERK的磷酸化。启动了相关的转录因子而维持肿瘤的干细胞特征。其上游受miRNA 200b的调控，并伴随着半乳糖凝集素3（GAL-3）的分泌增加。而GAL-3 又可以同细胞外基质中的成纤维细胞表面整合素B1结合，启动ILK的磷酸化，造成NF-KB的激活，大量分泌IL8，而IL-8 通过CXCR1 重新激发干细胞的活性。在此项研究中，我们探讨LOX与肝癌临床特征的联系，整合miRNA技术，分析、解释肝癌发生及转移分子生物学机制。进一步为探索肝癌治疗的分子靶标提供有价值线索，同时发现柑橘果胶具有抵抗干细胞维持的状态，具有潜在的开发价值。