Wang Zhe, Chen Jianfang, Sun Fengjun, Zhao Xiang, Dong Yan, Yu Songtao, Li Jianjun, Liang Houjie
Department of Oncology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
Department of Pharmacy, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
Cell Biosci. 2022 Jul 30;12(1):120. doi: 10.1186/s13578-022-00849-9.
Colorectal liver metastases (CRLM) continue to have a low survival rate. The number of CRLM regulators and clinical indicators remains limited. Long non-coding RNAs (lncRNAs) are a new master regulator of cell invasion and metastasis. However, the function and regulation mechanism of lncRNAs in colorectal cancer (CRC) metastasis are yet unknown.
To screen and identify CRLM-related lncRNAs, public transcriptome data were used. Gain and loss of function experiments were carried out to investigate the biological activities of lncRNA CRLM1 in vitro and in vivo. RNA sequencing (RNA-seq), chromatin isolation by RNA purification (ChIRP), immunofluorescence (IF), quantitative real-time PCR (qRT-PCR), western blotting, and rescue experiments were performed to explore the molecular mechanism of CRLM1. Moreover, identified the proteins, DNAs, and RNAs that interact with CRLM1.
The investigation of lncRNA expression dynamics in CRLM, primary CRC, and normal tissues in this work resulted in identifying a series of lncRNAs associated with metastasis, including CRLM1. CRLM1 inhibited apoptosis of CRC cells and promoted liver metastasis in Balb/C nude mice. CRLM1 was weakly associated with the chromatin regions of genes involved in cell adhesion and DNA damage, and this association was bidirectionally correlated with CRLM1-regulated pro-metastatic gene expression. CRLM1 physically interacts with the hnRNPK protein and promotes its nuclear localization. CRLM1 effectively enhances hnRNPK promoter occupancy and co-regulates the expression of a panel of metastatic genes.
The finding of the clinically significant lncRNA CRLM1 in promoting metastasis and regulating gene expression suggests a potential biomarker and target for CRLM therapy.
结直肠癌肝转移（CRLM）的生存率仍然较低。CRLM调节因子和临床指标的数量仍然有限。长链非编码RNA（lncRNA）是细胞侵袭和转移的新型主要调节因子。然而，lncRNA在结直肠癌（CRC）转移中的功能和调控机制尚不清楚。
利用公开的转录组数据筛选和鉴定与CRLM相关的lncRNA。进行功能获得和缺失实验，以研究lncRNA CRLM1在体外和体内的生物学活性。进行RNA测序（RNA-seq）、RNA纯化染色质分离（ChIRP）、免疫荧光（IF）、定量实时PCR（qRT-PCR）、蛋白质免疫印迹，并进行拯救实验，以探索CRLM1的分子机制。此外，鉴定了与CRLM1相互作用的蛋白质、DNA和RNA。
本研究对CRLM、原发性CRC和正常组织中lncRNA表达动态的研究，鉴定出一系列与转移相关的lncRNA，包括CRLM1。CRLM1抑制CRC细胞凋亡，并促进Balb/C裸鼠的肝转移。CRLM1与参与细胞黏附和DNA损伤的基因的染色质区域弱相关，且这种相关性与CRLM1调节的促转移基因表达呈双向关联。CRLM1与hnRNPK蛋白发生物理相互作用，并促进其核定位。CRLM1有效增强hnRNPK启动子占据，并共同调节一组转移基因的表达。
临床意义重大的lncRNA CRLM1在促进转移和调节基因表达方面的发现，提示其可能成为CRLM治疗的生物标志物和靶点。
