Ke Chao, Zhou Hongjian, Xia Tian, Xie Xingwang, Jiang Bin
The Department of Gastrointestinal, Hernia and Abdominal Wall Surgery, Wuhan Third Hospital (Tongren Hospital of Wuhan University), 241 Pengliuyang Road, Wuchang District, Wuhan, Hubei Province, 430060, China.
Heliyon. 2024 Mar 1;10(5):e27159. doi: 10.1016/j.heliyon.2024.e27159. eCollection 2024 Mar 15.
Colorectal cancer (CRC) is one of the most common cancers and the second most deadly cancer across the globe. Colorectal cancer stem cells (CCSCs) fuel CRC growth, metastasis, relapse, and chemoresistance. A complete understanding of the modulatory mechanisms of CCSC biology is essential for developing efficacious CRC treatment. In the current study, we characterized the expression and function of GTP binding protein 2 (GTPBP2) in a chemical-induced mouse CRC model. We found that GTPBP2 was expressed at a higher level in CD133CD44 CCSCs compared with other CRC cells. Using a lentivirus-based Cas9/sgRNA system, GTPBP2 expression was ablated in CRC cells . GTPBP2 deficiency caused the following effects on CCSCs: 1) Significantly accelerating proliferation and increasing the proportions of cells at G1, S, and G2/M phase; 2) Impairing resistance to 5-Fluorouracil; 3) Weakening self-renewal but not impacting cell migration. In addition, GTPBP2 deficiency remarkably decreased β-catenin expression while increasing β-catenin phosphorylation in CCSCs. These effects of GTPBP2 were present in CCSCs but not in other CRC cell populations. The Wnt agonist SKL2001 completely abolished these changes in GTPBP2-deficient CCSCs. When GTPBP2-deficient CCSCs were implanted in nude mice, they exhibited consistent changes compared with GTPBP2-expressing CCSCs. Collectively, this study indicates that GTPBP2 positively modulates Wnt signaling to reinforce the quiescence, self-renewal, and chemoresistance of mouse CCSCs. Therefore, we disclose a novel mechanism underlying CCSC biology and GTPBP2 could be a therapeutic target in future CRC treatment.
结直肠癌（CRC）是全球最常见的癌症之一，也是第二大致命癌症。结直肠癌干细胞（CCSCs）推动CRC的生长、转移、复发和化疗耐药性。全面了解CCSC生物学的调节机制对于开发有效的CRC治疗方法至关重要。在本研究中，我们在化学诱导的小鼠CRC模型中表征了GTP结合蛋白2（GTPBP2）的表达和功能。我们发现，与其他CRC细胞相比，GTPBP2在CD133CD44 CCSCs中的表达水平更高。使用基于慢病毒的Cas9/sgRNA系统，在CRC细胞中敲除了GTPBP2的表达。GTPBP2缺乏对CCSCs产生了以下影响：1）显著加速增殖并增加处于G1、S和G2/M期的细胞比例；2）损害对5-氟尿嘧啶的耐药性；3）削弱自我更新能力，但不影响细胞迁移。此外，GTPBP2缺乏显著降低了CCSCs中β-连环蛋白的表达，同时增加了β-连环蛋白的磷酸化。GTPBP2的这些作用存在于CCSCs中，而不存在于其他CRC细胞群体中。Wnt激动剂SKL2001完全消除了GTPBP2缺陷型CCSCs中的这些变化。当将GTPBP2缺陷型CCSCs植入裸鼠体内时，与表达GTPBP2的CCSCs相比，它们表现出一致的变化。总的来说，本研究表明GTPBP2正向调节Wnt信号通路，以增强小鼠CCSCs的静止、自我更新和化疗耐药性。因此，我们揭示了CCSC生物学的一种新机制，GTPBP2可能成为未来CRC治疗的一个靶点。
