Department of Gastrointestinal Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Supported by National Key Clinical Discipline, Guangzhou, Guangdong, P.R.China.
Department of Gastrointestinal Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Supported by National Key Clinical Discipline, Guangzhou, Guangdong, P.R.China
J Pharmacol Exp Ther. 2021 Jun;377(3):358-367. doi: 10.1124/jpet.121.000518. Epub 2021 Mar 26.
Recently, circular RNA was reported to be a significant participant in the development of tumorigenesis, including colorectal cancer. Therefore, we aimed to clarify the precise role of circ-keratin 6C (circ-KRT6C) in colorectal cancer progression. The relative expression levels of circ-KRT6C, microRNA-485-3p (miR-485-3p), and programmed cell death receptor ligand 1 (PDL1) were analyzed by real-time quantitative polymerase chain reaction and Western blot assays. The proliferation was assessed by cell count kit 8 and colony-forming assays. The apoptotic cells were determined by flow cytometry assay. The migration and invasion were analyzed by transwell assay. Colorectal cancer cells were cocultured with peripheral blood mononuclear cells or cytokine-induced killer cells to assess immune response. The interaction relationships among circ-KRT6C, miR-485-3p, and PDL1 were examined by dual-luciferase reporter assay. The effects of circ-KRT6C inhibition in vivo were analyzed by an animal experiment. circ-KRT6C was overexpressed in colorectal cancer tissues and cells, and its level was associated with overall survival time of patients with colorectal cancer. The suppression of circ-KRT6C suppressed growth, migration, invasion, and immune escape while stimulating apoptosis in colorectal cancer cells, which was abolished by shortage of miR-485-3p. In addition, overexpression of miR-485-3p repressed malignant progression and immune evasion of colorectal cancer by targeting PDL1, implying that PDL1 was a functional target of miR-485-3p. A xenograft experiment also suggested that circ-KRT6C inhibition could repress tumor growth in vivo. circ-KRT6C could increase PDL1 expression by functioning as an miR-485-3p sponge, which promoted malignant progression and immune evasion of colorectal cancer cells. SIGNIFICANCE STATEMENT: circ-keratin 6c could increase programmed cell death receptor ligand 1 expression by functioning as a microRNA-16-5p sponge, which promoted malignant progression and immune evasion of colorectal cancer.
最近，环状 RNA 被报道在肿瘤发生发展中扮演着重要角色，包括结直肠癌。因此，我们旨在阐明环状角蛋白 6C（circ-KRT6C）在结直肠癌进展中的精确作用。通过实时定量聚合酶链反应和 Western blot 分析检测 circ-KRT6C、微小 RNA-485-3p（miR-485-3p）和程序性死亡受体配体 1（PDL1）的相对表达水平。通过细胞计数试剂盒 8 和集落形成实验评估增殖。通过流式细胞术检测凋亡细胞。通过 Transwell 分析评估迁移和侵袭。将结直肠癌细胞与外周血单个核细胞或细胞因子诱导的杀伤细胞共培养，以评估免疫反应。通过双荧光素酶报告基因实验检测 circ-KRT6C、miR-485-3p 和 PDL1 之间的相互作用关系。通过动物实验分析 circ-KRT6C 抑制的体内效应。circ-KRT6C 在结直肠癌组织和细胞中过表达，其水平与结直肠癌患者的总生存时间相关。circ-KRT6C 的抑制抑制了结直肠癌细胞的生长、迁移、侵袭和免疫逃逸，而 miR-485-3p 的缺乏则消除了这种抑制作用。此外，miR-485-3p 通过靶向 PDL1 抑制结直肠癌细胞的恶性进展和免疫逃逸，表明 PDL1 是 miR-485-3p 的功能靶标。异种移植实验也表明，circ-KRT6C 抑制可抑制体内肿瘤生长。circ-KRT6C 通过作为 miR-485-3p 的海绵体增加 PDL1 表达，从而促进结直肠癌细胞的恶性进展和免疫逃逸。
circ-KRT6C 通过作为 miR-16-5p 的海绵体增加程序性死亡受体配体 1 的表达，从而促进结直肠癌的恶性进展和免疫逃逸。
