Guangdong Institute of Gastroenterology, Guangzhou, China; Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China; Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Guangdong Institute of Gastroenterology, Guangzhou, China; Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
EBioMedicine. 2023 Jul;93:104650. doi: 10.1016/j.ebiom.2023.104650. Epub 2023 Jun 19.
Pyrimidine nucleotides fuel the growth of colorectal cancer (CRC), making their associated proteins potential targets for cancer intervention. Uridine-Cytidine Kinase Like-1(UCKL1) is an enzyme involved in the pyrimidine salvage pathway. It is highly expressed in multiple cancers. But the function and underlying mechanism of UCKL1 in CRC are yet to study.
Large-scale genomic analysis was performed to search for potential CRC players related to pyrimidine metabolism. The function of UCKL1 in CRC were examined by RNA interference coupled with in vitro and in vivo assays. GSH/GSSG assay, NADP+ assay, ROS, and Lipid peroxidation assays were performed to check the function of UCKL1 in ferroptosis. Metabolomics analyses, RNA sequencing, western blotting, and rescue assays were done to reveal the underlying mechanisms of UCKL1. Xenograft mouse model was used to examine the therapeutic potential of UCKL1 as a target in combination with other ferroptosis inducers.
UCKL1 was identified to repress ferroptosis in CRC cells. It was highly expressed in CRC. It regulated CRC cells proliferation and migration. Downregulation of UCKL1 led to enhanced tumour lipid peroxidation. Intriguingly, UCKL1 reduction-mediated ferroptosis was not related to its role in catalyzing uridine monophosphate (UMP) and cytidine monophosphate (CMP) synthesis. Instead, UCKL1 stabilized Nrf2, which in turn promoted the expression of SLC7A11, a classical repressor of ferroptosis. Moreover, downregulation of UCKL1 sensitized CRC cells to GPX4 inhibitors in vitro and in vivo.
Our study demonstrates that UCKL1 plays a non-canonical role in repressing ferroptosis through a UCKL1-Nrf2-SLC7A11 axis in CRC cells. Combinatorial strategy in targeting ferroptosis by depletion of UCKL1 and application of GPX4 inhibitors may serve as a new effective method for CRC treatment.
This study was supported in part by fund from National Natural Science Foundation of China (Grant No. 31970674 to PY), by the Basic and Applied Basic Research Program of Guangdong Province (Grant No. 2023A1515030245 to KL), by the program of Guangdong Provincial Clinical Research Center for Digestive Diseases (2020B1111170004), and by National Key Clinical Discipline.
嘧啶核苷酸为结直肠癌（CRC）的生长提供燃料，使其相关蛋白成为癌症干预的潜在靶点。尿嘧啶-胞苷激酶样 1（UCKL1）是参与嘧啶补救途径的一种酶。它在多种癌症中高表达。但是，UCKL1 在 CRC 中的功能和潜在机制尚未研究。
进行大规模基因组分析以寻找与嘧啶代谢相关的潜在 CRC 参与者。通过体外和体内测定结合 RNA 干扰来检查 UCKL1 在 CRC 中的功能。进行 GSH/GSSG 测定、NADP+测定、ROS 和脂质过氧化测定，以检查 UCKL1 在铁死亡中的功能。进行代谢组学分析、RNA 测序、western blot 和挽救测定，以揭示 UCKL1 的潜在机制。使用异种移植小鼠模型来研究 UCKL1 作为与其他铁死亡诱导剂联合的靶标的治疗潜力。
发现 UCKL1 可抑制 CRC 细胞中的铁死亡。它在 CRC 中高表达。它调节 CRC 细胞的增殖和迁移。UCKL1 下调导致肿瘤脂质过氧化增强。有趣的是，UCKL1 下调介导的铁死亡与其在催化尿苷单磷酸（UMP）和胞苷单磷酸（CMP）合成中的作用无关。相反，UCKL1 稳定了 Nrf2，进而促进了 SLC7A11 的表达，SLC7A11 是铁死亡的经典抑制剂。此外，在体外和体内，下调 UCKL1 可使 CRC 细胞对 GPX4 抑制剂敏感。
我们的研究表明，UCKL1 通过 CRC 细胞中的 UCKL1-Nrf2-SLC7A11 轴发挥非典型作用，抑制铁死亡。通过耗尽 UCKL1 和应用 GPX4 抑制剂靶向铁死亡的联合策略可能成为 CRC 治疗的一种新的有效方法。
本研究部分得到国家自然科学基金（PY 资助号 31970674）、广东省基础与应用基础研究基金（KL 资助号 2023A1515030245）、广东省消化疾病临床研究中心项目（2020B1111170004）和国家重点临床专科的资助。
