Slc27a2/5介导的外源脂肪酸摄取在肝内胆管癌发生中的作用及靶向阻断研究

Intrahepatic cholangiocarcinoma (ICC) has a high degree of malignancy and lack of treatment. Therefore, it is necessary to study its pathogenesis and seek therapeutic targets. We have found that different with HCC, which synthesize fatty acids by itself, ICC cell growth are highly dependent on exogenous uptake of fatty acid. In addition, fatty acid transporters Slc27a2 and Slc27a5 were highly expressed in ICC cells and tissues. Blocking exogenous fatty acid uptake by transporter inhibitors can effectively inhibit ICC cell growth. Accordingly, we propose the hypothesis that the occurrence and development of ICC is highly dependent on Slc27a2/5 mediated exogenous fatty acid uptake, and inhibition of Slc27a2/5 can block the occurrence and development of ICC. In this study, we will use tail vein hydrodynamic injection to construct the ICC mouse model in situ. Combined with Slc27a2/5 knockout mice, we can observe whether knockout of Slc27a2/5 can block ICC fatty acid uptake, and then block the development of ICC. In addition, we will also identify fatty acid sources in ICC and to demonstrate whether the fatty acid can be obtained through de novo lipogenesis after blocking the uptake of exogenous fatty acid. This study will be able to determine whether the Slc27a2/5 mediated exogenous fatty acid uptake pathway can be used as an effective target for ICC treatment.

肝内胆管癌(ICC)恶性程度高且治疗手段匮乏，因此有必要研究其发病机制并寻找治疗靶点。我们前期发现ICC细胞生长所需脂肪酸高度依赖于外源获取。此外，脂肪酸转运蛋白Slc27a2和Slc27a5在ICC细胞和组织中均高表达，转运蛋白抑制剂阻断脂肪酸摄取可以有效抑制ICC细胞生长。据此我们提出假说：ICC发生发展高度依赖于Slc27a2/5介导的外源性脂肪酸摄取，抑制Slc27a2/5可以阻断ICC的发生与发展。本研究中，我们将使用尾静脉高压注射转染构建小鼠ICC原位癌模型，并结合Slc27a2/5敲除小鼠观察敲除Slc27a2/5是否可以阻断ICC脂肪酸摄取，并进而抑制ICC发生发展。此外，我们也将考察ICC摄取脂肪酸的来源以及阻断外源脂肪酸合成后能否通过内源合成获取脂肪酸。本研究将能够确定介导脂肪酸摄取的Slc27a2/5是否可以作为ICC治疗的有效靶标。

肝内胆管癌（ICC）进展快，恶性程度高，但治疗手段匮乏且缺乏靶向药物。前期研究中我们外源性脂肪酸并非ICC肿瘤细胞的主要能量来源，抑制外源性转运蛋白SLC27A1、SLC27A2及SLC2 7A5后发现抑制外源脂肪酸的摄入并不能显著抑制AKT/NICD诱发的ICC。随后我们发现Sirt6在人ICC中高表达，敲除Sirt6可以抑制小鼠ICC发生和ICC细胞生长，而过表达Sirt6可以在小鼠体内驱动ICC发生。进一步考察发现，沉默Sirt6不影响ICC细胞葡萄糖和脂肪代谢，而且Sirt6可以上调谷氨酰胺合成酶基因GLUL，调控ICC细胞自主合成谷氨酰胺和促进ICC发生。功能分析发现，Sirt6沉默后ICC细胞内自主合成谷氨酰胺含量减少，氨基酸、蛋白质、核苷酸合成受到抑制。随后，我们提出假说：Sirt6通过上调GLUL调控谷氨酰胺代谢重新编程，并最终促进ICC发生。我们希望接下去利用基因敲除小鼠模型考察阻断Sirt6和GLUL是否可以抑制小鼠体内发生与发展，并利用细胞模型和分子生物学技术考察Sirt6对GLUL调控的分子机制。本研究将能够确认Sirt6是否可以作为ICC治疗的靶标，并揭示Sirt6驱动ICC发生的分子机制。