超级增强子源cirRNA-EYA3作为ceRNA调控ATM—DNA损伤通路参与肝癌对125I放射抵抗的机制研究

The radiation resistance of 125I seed is a difficult problem for the treatment of liver cancer. Based on our own in vitro model of 125I seed radiobiology, we first discovered ATM was the important signal factor of DNA damage response mediated by 125I seed in tumor cells. High-throughput sequencing was found a super-enhancer cirRNA-EYA3 gene is an important initiating factor in regulation of ATM mediated DNA The effect of microenvironment changes on 125I radiation is unknown. Exosome is an important medium for the formation of tumor microenvironment in recent years. We extracted the exosomes from the blood of patients with hepatocellular carcinoma before and after 125I treatment. LongRNA sequencing revealed that circRNA-EYA3 (hsa_circ_0007895) increased significantly which were verified in cell, animal and clinical samples. Subsequently, CHIP-seq experiment found it was derived from the enhancer region of liver cancer stem cells. Previous studies found that the mechanism may be through the adsorption of miR-124 to upregulate m6A reading protein IGF2BP1, thereby improving the transcriptional stability of RNA, promoting cell survival and upregulating cell radiation tolerance. This study was used meRIP-seq in vitro and in vivo experiments to elucidate exosomal enhanced circRNA-EYA3 radiation resistance of 125I therapy in hepatocellular carcinoma effect and epigenetic mechanisms; and used large sample validation to verify circRNA-EYA3 as viable hepatocellular carcinoma and prognostic indicators of radiation tolerance. This project will be expected to reveal new mechanisms of 125I therapy and explore new prognostic markers for the prognosis of liver cancer.

放射粒子125I治疗后肝癌微环境变化对125I近距离放射作用影响机制不详。外泌体是近年报道形成肿瘤进展微环境的重要媒介。我们提取125I治疗前后肝癌患者血液中的外泌体，经longRNA测序发现circRNA-EYA3（hsa_circ_0007895）显著升高，并在细胞、动物及临床样本中验证。随后，CHIP-seq等实验发现其来源于肝癌干细胞的增强子区域，前期研究发现其机制可能是通过吸附miR-124上调m6A读取蛋白IGF2BP1，从而提高RNA转录稳定性而促进细胞存活，上调细胞辐射耐受。本课题拟进一步通过meRIP-seq等体内外实验阐明125I粒子治疗下，exosomal circRNA-EYA3增强肝癌放射抵抗的作用及表观遗传机制；并通过大样本验证，明确circRNA-EYA3作为肝癌放射耐受及预后指标的可行性。本课题将有望揭示放射粒子介入治疗的新机制和发掘肝癌放疗预后新标志物。

放射性125I粒子治疗后肝癌微环境变化对125I近距离放射作用影响机制不详。外泌体是近年报道形成肿瘤进展微环境的重要媒介。我们前期已提取125I治疗前后肝癌患者血液中的外泌体，经longRNA测序发现circRNA-EYA3（hsa_circ_0007895）显著升高，并在细胞、动物及临床样本中验证。本课题进一步通过125I粒子和X射线放射生物学体外模型，探索了circEYA3对肝癌细胞生物学行为的影响，并深入探讨了circEYA3介导125I粒子治疗放射抵抗的分子机制，circEYA3通过与IGF2BP2蛋白结合上调了DTX3L的表达。本课题有望为肝癌的放射治疗提供新靶点和干预机制，从circRNA这一角度揭示肝癌对125I粒子放射抵抗的发生发展机理。