IscU2调控alpha-酮戊二酸代谢机制及胰腺癌精准诊疗标志物研究

胰腺导管腺癌（PDAC）的发生发展高度依赖于谷氨酰胺代谢，但我们在前期研究中发现谷氨酰胺的代谢产物alpha-酮戊二酸（AKG）能够显著抑制癌细胞的增殖，提示胰腺癌细胞可能存在一种未知的调控途径来降低细胞内AKG的堆积。初步的机制研究表明：IscU2的表达水平与胰腺癌细胞中AKG的含量呈负相关；结合全基因组甲基化/羟甲基化/表达谱联合分析，我们发现IscU2可能通过促进AKG的代谢维持POLA1的甲基化进而避免癌细胞阻滞在S期。为了验证这一假设，我们将以细胞和动物模型为研究对象，利用代谢流技术明确IscU2对AKG的代谢调控；通过细胞与生物化学技术明确IscU2/AKG/POLA1甲基化轴在PDAC细胞增殖中的作用；通过体内实验初步评估AKG对胰腺癌治疗的个体化差异是否与癌组织中的IscU2和AKG水平相关，最终为基于IscU2和AKG分子标志物的PDAC病人精准诊疗评价提供理论支持。

Pancreatic ductal adenocarcinoma (PDAC) cells are highly glutamine addictive. Our preliminary data suggest that alpha-ketoglutarate (AKG)，as an intermediator of glutaminolysis, can efficiently inhibit the growth of PDAC cell, these results suggest that may have unknown regulatory pathways to reduce the accumulation of AKG in pancreatic cancer cells. Our preliminary studies showed that the expression level of IscU2 was inversely correlated with AKG，In combination analysis of whole genome 5-mc/5-hmc sequencing and transcriptome profiling, we found IscU2 may facilitate the degradation of AKG to maintain the low de-methylation status of POLA1 gene that promote cell cycle progression. To fully understand the role of IscU2/AKG/POLA1 methylation and demethylation status in the growth of PDAC cells, we are planning to determine the regulatory mechanism of IscU2 on AKG in 8988 and PANC-1 cells by using the strategy of metabolic flux. With the same cell models and animal models, IscU2/AKG/POLA1 axis in the regulation of cancer cell proliferation in vitro and in vivo will be studied. Moreover, to evaluate the if IscU2 can be a qualified candidate for precision medicine, responsive effect of cancer cell growth inhibition by targeting IscU2/AKG/POLA1 methylation and demethylation will be tested in patient-derived xenografts with different expression level of IscU2.