Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province, Hangzhou, China.
Cancer Res Treat. 2021 Jan;53(1):184-198. doi: 10.4143/crt.2020.192. Epub 2020 Oct 5.
Intrahepatic cholangiocarcinoma (ICC) is one of the most common liver primary tumors but its treatments are limited. Bioinformatics showed that the expression level of long non-coding RNA cancer-associated susceptibility 15 gene (CASC15) is correlated with ICC progression, but its functional mechanism remains unclear.
Tissues from ICC patients, tumor and adjacent tissue, were used for detection of the expression of CASC15. Clinical data were also collected for clinicopathologic and survival analysis. Short interfering RNA and lentiviral short hairpin RNA were used to knock down CASC15 and PRDX2 expression in ICC cell lines, for the analysis of changes of cell function and xenografts. RNA-pulldown and RNA immunoprecipitation assays were used to detect RNA-binding protein, PRDX2. Male nude mice were used for ICC xenografts, and livers were collected after 4 weeks for immunohistochemistry.
CASC15 is highly expressed in ICC tissues and is related to higher TNM stage. Knockdown of CASC15 in ICC cells reduced cell proliferation, migration, invasiveness and increased apoptosis, and G1/S block. PRDX2 bound to CASC15. Knockdown of CASC15 decreased PRDX2 expression which was rescued by the inhibition of proteasome formation. Downregulation of PRDX2 resulted in G1/S block, reduced ICC cell invasion. Downregulation of CASC15 inhibited phosphoinositide 3-kinase (PI3K)/AKT/c-Myc pathway through downregulating of PRDX2 and overexpressed PRDX2 rescued the block. CASC15 knockout in ICC xenografts suppressed tumor development in vivo, decreased the expression of PRDX2 and Ki67 and inhibited PI3K/AKT pathway.
CASC15 promotes ICC possibly by targeting PRDX2 via the PI3K/AKT pathway, indicating poor prognosis and high degree of malignancy of ICC.
肝内胆管癌（ICC）是最常见的肝脏原发性肿瘤之一，但治疗方法有限。生物信息学显示，长链非编码 RNA 癌相关易感性 15 号基因（CASC15）的表达水平与 ICC 的进展相关，但功能机制尚不清楚。
使用 ICC 患者的肿瘤和相邻组织的组织检测 CASC15 的表达。还收集了临床数据以进行临床病理和生存分析。使用短发夹 RNA 干扰和慢病毒短发夹 RNA 敲低 ICC 细胞系中的 CASC15 和 PRDX2 表达，分析细胞功能和异种移植的变化。RNA 下拉和 RNA 免疫沉淀实验用于检测 RNA 结合蛋白 PRDX2。雄性裸鼠用于 ICC 异种移植，4 周后收集肝脏进行免疫组织化学分析。
CASC15 在 ICC 组织中高表达，与更高的 TNM 分期相关。在 ICC 细胞中敲低 CASC15 可降低细胞增殖、迁移、侵袭和增加细胞凋亡，同时使 G1/S 期阻滞。PRDX2 与 CASC15 结合。敲低 CASC15 降低了 PRDX2 的表达，而蛋白酶体形成的抑制可挽救这种情况。下调 PRDX2 导致 G1/S 期阻滞，降低 ICC 细胞侵袭。下调 CASC15 通过下调 PRDX2 抑制磷脂酰肌醇 3-激酶（PI3K）/AKT/c-Myc 通路，而过表达 PRDX2 可挽救这种阻滞。在 ICC 异种移植中敲除 CASC15 可抑制体内肿瘤的发展，降低 PRDX2 和 Ki67 的表达，并抑制 PI3K/AKT 通路。
CASC15 可能通过靶向 PRDX2 并通过 PI3K/AKT 通路促进 ICC 的发展，表明 ICC 预后不良且恶性程度高。
