School of Basic Medical Sciences, Qiqihar Medical University, Qiqihar, 161006, Heilongjiang, China.
Department of Oncology, Harbin Medical University Cancer Hospital, Harbin, 150081, Heilongjiang, China.
Cell Oncol (Dordr). 2021 Jun;44(3):557-568. doi: 10.1007/s13402-020-00582-w. Epub 2021 Jan 19.
Cervical cancer remains a major cause of cancer-related death in women, especially in developing countries. Previously, we found that the acetylation levels of chloride intracellular channel 1 (CLIC1) at lysine 131 were increased in cervical cancer tissues using a label-free proteomics approach. The aim of this study was to further determine the role of CLIC1 expression and its acetylation in cervical cancer.
CLIC1 expression and its implications for the prognosis of cervical cancer were analyzed using primary patient samples and cells, and the Gene Expression Profiling Interactive Analysis (GEPIA) database (gepia.cancer-pku.cn). The effect of CLIC1 on cervical cancer cells was evaluated using Cell Counting Kit (CCK)-8, flow cytometry, scratch wound healing, transwell, Western blotting and co-immunoprecipitation (Co-IP) assays. In vivo tumor growth was assessed using mouse xenograft models.
We found that CLIC1 expression was increased in cervical cancer tissues and cells and that patients with a high CLIC1 expression tended to have a shorter overall survival time. Knockdown of CLIC1 significantly reduced in vitro cervical cancer cell proliferation, migration and invasion, and in vivo tumorigenesis. At the molecular level, we found that nuclear factor kappa B (NF-κB) activity was positively regulated by CLIC1. Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, attenuated the tumor-promoting effect of CLIC1. Moreover, we found that CLIC1 acetylation at K131 was upregulated in cervical cancer cells, which stabilized CLIC1 by inhibiting its ubiquitynation. Substitution of K131 inhibited CLIC1 ubiquitynation and promoted in vitro cervical cancer cell proliferation, migration and invasion, and in vivo tumor growth. In addition, we found that acetyltransferase HAT1 was responsible for CLIC1 acetylation at K131.
Our data indicate that CLIC1 acts as a tumor promoter in cervical cancer, suggesting a potential treatment strategy for cervical cancer by regulating CLIC1 expression and/or acetylation.
宫颈癌仍然是导致女性癌症相关死亡的主要原因，尤其是在发展中国家。此前，我们使用无标记蛋白质组学方法发现氯离子通道 1（CLIC1）在赖氨酸 131 处的乙酰化水平在宫颈癌组织中增加。本研究旨在进一步确定 CLIC1 表达及其在宫颈癌中的乙酰化作用。
使用原发性患者样本和细胞以及基因表达谱分析交互分析（GEPIA）数据库（gepia.cancer-pku.cn）分析 CLIC1 表达及其对宫颈癌预后的影响。使用细胞计数试剂盒（CCK）-8、流式细胞术、划痕愈合试验、Transwell 试验、Western blot 印迹和免疫共沉淀（Co-IP）试验评估 CLIC1 对宫颈癌细胞的影响。使用小鼠异种移植模型评估体内肿瘤生长。
我们发现 CLIC1 表达在宫颈癌组织和细胞中增加，并且 CLIC1 高表达的患者倾向于具有更短的总生存时间。CLIC1 敲低显著降低了体外宫颈癌细胞的增殖、迁移和侵袭，以及体内肿瘤发生。在分子水平上，我们发现核因子 kappa B（NF-κB）活性受 CLIC1 正向调节。NF-κB 抑制剂吡咯烷二硫代氨基甲酸酯（PDTC）减弱了 CLIC1 的促肿瘤作用。此外，我们发现宫颈癌细胞中 CLIC1 在 K131 处的乙酰化增加，通过抑制其泛素化稳定 CLIC1。K131 的取代抑制 CLIC1 泛素化，并促进体外宫颈癌细胞的增殖、迁移和侵袭，以及体内肿瘤生长。此外，我们发现乙酰转移酶 HAT1 负责 CLIC1 在 K131 处的乙酰化。
我们的数据表明，CLIC1 作为宫颈癌的肿瘤促进因子发挥作用，提示通过调节 CLIC1 表达和/或乙酰化可能成为宫颈癌的潜在治疗策略。
