肝癌癌基因ARL影响S1P信号通路在肝癌发病机制中的作用及靶向干预研究

It is estimated that about half of the global liver cancers is in China, which seriously endanger the health of our people. Because of the lack of stable and effective treatments in liver cancer, to explore new measures is imminent. Literature and our previous work confirmed that aldose reductase like gene (ARL) cloned from primary hepatocellular carcinoma is closely related to liver cancer. A recent report revealed that ARL is important to cell survival in other tumor cells, and gene silence by RNAi or inhibition by Epalrestat can lead cancer cell death. Moreover,lipids, especially phospholipids, reduced by more than 50% in these cells. As a naturally occurring phospholipid, S1P which is a key molecule of sphingolipid signaling pathway can mediate cell survival and the role of S1P in oncogenesis and tumor growth has been proven. We hypothesize: ARL promotes liver cancer cell growth and ARL inhibition induces liver cancer cell death by affecting the level of S1P; intervention in the ARL-S1P signaling pathway may be used in therapy of liver cancer. This project will study the mechanisms of ARL regulating S1P and help to elucidate the role of ARL in liver cancer; and further explore the feasibility of liver cancer therapy which is targeted to ARL-S1P signaling pathway.

据统计全球肝癌半数左右在中国，严重危害着我国人民的健康。对于肝癌，目前尚缺乏稳定有效的治疗方法，探索新的治疗措施迫在眉睫。醛糖还原酶相似基因（ARL）是从原发性肝癌组织中克隆的一个基因,文献报道和我们的前期工作证明ARL与肝癌关系密切。近期在其它肿瘤细胞发现ARL是肿瘤细胞存活的关键，RNAi介导的ARL基因沉默和Epalrestat对ARL的抑制能导致肿瘤细胞死亡；在ARL抑制的肿瘤细胞里脂质，尤其是磷脂降低50%以上。作为天然磷脂，S1P是神经鞘脂通路的关键分子，它能介导细胞存活，S1P还与肿瘤发生和肿瘤生长有关。我们假设：ARL能促进肝癌细胞生长，抑制ARL能诱导肝癌细胞死亡，其机制是通过调控 S1P水平；干预ARL-S1P信号通路能起到治疗肝癌的效果。本课题将研究ARL调控S1P的机制，为阐明ARL在肝癌中的作用提供帮助；并进一步以ARL-S1P信号通路为靶点探讨肝癌治疗的可行性。

据统计全球肝癌半数左右在中国，严重危害着我国人民的健康。对于肝癌，目前尚缺乏稳定有效的治疗方法，探索新的治疗措施迫在眉睫。醛糖还原酶相似基因（ARL，又叫AKR1B10）是从原发性肝癌组织中克隆的一个基因，文献报道和我们的前期工作证明AKR1B10与肝癌关系密切。近期在其它肿瘤细胞发现AKR1B10是肿瘤细胞存活的关键，RNAi介导的AKR1B10基因沉默和Epalrestat对AKR1B10的抑制能导致肿瘤细胞死亡；在AKR1B10抑制的肿瘤细胞里脂质，尤其是磷脂，降低50%以上。作为天然磷脂，S1P是神经鞘脂通路的关键分子，它能介导细胞存活，S1P还与肿瘤发生和肿瘤生长有关。本课题拟在细胞水平研究外源性AKR1B10基因表达增加S1P促进肝细胞生长的机制，以及AKR1B10抑制对S1P及肝癌细胞生长的影响及机制；在动物水平研究外源性AKR1B10基因表达对小鼠肝癌形成的影响，以及靶向干预AKR1B10-S1P信号通路对小鼠肝癌形成的影响。结果表明：人肝细胞QSG-7701与人肝癌细胞HepG2联合培养促进前者的细胞增殖；与HepG2共培养促进QSG-7701细胞增殖是由于两种细胞表达AKR1B10的水平差异引起的；S1P是AKR1B10的下游信号分子，在与HepG2联合培养促进QSG-7701细胞增殖中起关键作用；AKR1B10和S1P在原发性肝癌中水平增加，AKR1B10的mRNA表达水平与血清AFP的水平、肿瘤TNM分期和淋巴结转移相关，高mRNA水平预示更短的术后无瘤生存期（DFS）和总生存期（OS），高mRNA水平是肝癌术后独立预测指标。用AKR1B10抑制剂OA和S1P抑制剂FTY720对AKR1B10-S1P 信号通路进行靶向干预，两个抑制剂均显著抑制肝癌生长。OA和FTY720明显抑制ASAH1的表达，对ASAH3的影响不明显，表明ASAH1可能是AKR1B10-S1P信号通路的关键分子。结论：AKR1B10促进肝癌细胞生长是通过调控S1P来实现的，ASAH1可能是AKR1B10-S1P信号通路的关键分子，靶向打击AKR1B10-S1P信号通路能抑制肿瘤，达到治疗肝癌的效果。