SMYD3调控谷氨酰胺代谢促进肝内胆管癌进展的机制研究

Metabolic reprograming plays a pivotal role in tumor progression, and GDH is the key relulator of glutamine metabolism. Previously, we showed that histone methyltransferase SMYD3 was up-regulated in intrahepatic cholangiocarcinoma and promoted tumor progression. However, the molecular mechanism is largely unknown. In the present study, We found that glutamine is important for intrahepatic cholangiocarcinoma cell proliferation and si-SMYD3 can prevent uptake of glutamine. Moreover, GDH was up-regulated in intrahepatic cholangiocarcinoma, and positively correlated with SMYD3 expression. GDH knockdown could significantly inhibit cell proliferation and tumor growth. SIRT3 is a key regulater for GDH and up-regulated in intrahepatic cholangiocarcinoma. More importantly, bioinformatic analysis showed that SIRT3 gene promoter region share several SMYD3 binding sites. Therefore, we hypothesis that SMYD3 may promot tumor progression through SIRT3-GDH mediated glutamine metabolism. This project will use ChIP-PCR and small interference RNA to study the role and mechanisms of SMYD3 mediated glutamine metabolism in intrahepatic cholangiocarcinoma, which would represent a novel link between metabolic reprogramming and epigenetic regulation.

能量代谢重构在肿瘤进展中发挥重要作用，谷氨酸脱氢酶(GDH)是调控谷氨酰胺代谢的关键酶。我们前期证实组蛋白甲基化转移酶SMYD3的高表达与肝内胆管癌进展密切相关。近期发现，谷氨酰胺缺乏可促进肝内胆管癌细胞凋亡，沉默SMYD3可抑制谷氨酰胺的摄取。预实验发现：①GDH在肝内胆管癌中高表达且与SMYD3正相关；②沉默GDH可抑制肝内胆管癌细胞的增殖和肿瘤生长；③生物信息学分析显示GDH上游调控基因SIRT3启动子区存在多个SMYD3锌指结构域结合位点。因此我们提出：SMYD3通过SIRT3上调GDH的表达，进而调控谷氨酰胺代谢促进肝内胆管癌进展的科学假说。本项目拟进一步采用ChIP-PCR、慢病毒转染、RNA干扰等技术，探讨谷氨酰胺代谢在肝内胆管癌进展中的作用，及SMYD3对GDH的调控机制，旨在获得表观遗传修饰异常调控能量代谢重构促进肝内胆管癌进展的可靠证据，为肝内胆管癌的治疗提供新思路。

能量代谢重构在肿瘤进展中发挥重要作用，谷氨酸脱氢酶(GDH)是调控谷氨酰胺代谢的关键酶且受SIRT3调控。组蛋白甲基化转移酶SMYD3通过调控下游基因促进肿瘤进展。本研究中，我们发现SMYD3在肝内胆管癌中高表达，与SIRT3、GDH，及预后不良等临床指标相关。沉默SMYD3可抑制肝内胆管癌细胞增殖、侵袭能力，及肿瘤生长和转移能力，及抑制谷氨酰胺代谢。机制研究发现，SMYD3可与SIRT3启动子区结合进而调控GDH的表达参与谷氨酰胺代谢调控。本研究为表观遗传修饰异常调控能量代谢重构促进肝内胆管癌进展提供了重要实验证据，为肝内胆管癌的治疗提供新思路。