In vivo NCL-targeting affects breast cancer aggressiveness through miRNA regulation [RNA-seq]

Numerous studies have described the altered expression and the causal role of miRNAs in human cancer. However, to date efforts to modulate miRNA levels for therapeutic purposes have been challenging to implement. Here, we find that Nucleolin (NCL), a major nucleolar protein, post-transcriptionally regulates the expression of a specific subset of miRNAs, including miR-21, miR-221, miR-222, and miR-103, causally involved in breast cancer initiation, progression and drug-resistance. We also show that NCL is commonly overexpressed in human breast tumors, and its expression correlates with that of NCL-dependent miRNAs. Finally, this study indicates that NCL-binding guanosine-rich aptamers affect the levels of NCL-dependent miRNAs and their target genes, reducing breast cancer cell aggressiveness, both in vitro and in vivo. These findings illuminate a path to novel therapeutic approaches based on NCL-targeting aptamers for the modulation of miRNA expression in the treatment of breast cancer. Identification of NCL regulated miRNAs by using miRNA high-throughput sequencing of HeLa cells stably expressing double-strand (ds) interfering RNA against NCL or scrambled sequences (sh-NCL or sh-Scr).

已有诸多研究阐明了微小RNA（miRNAs）在人类癌症中的异常表达及其致病作用。然而迄今为止，针对治疗用途调控微小RNA表达水平的相关尝试始终难以落地实施。本研究发现，作为主要核仁蛋白的核仁素（Nucleolin, NCL）可在转录后水平调控一类特定微小RNA的表达，其中包括miR-21、miR-221、miR-222及miR-103，这些微小RNA均与乳腺癌的发生、进展及耐药性存在直接因果关联。本研究同时证实，核仁素在人类乳腺肿瘤中普遍呈现高表达状态，且其表达水平与依赖核仁素的微小RNA的表达呈显著正相关。最后，本研究表明，结合核仁素的富鸟苷酸适配体可调控依赖核仁素的微小RNA及其靶基因的表达水平，在体外及体内实验中均能降低乳腺癌细胞的侵袭性。上述研究结果为基于靶向核仁素适配体的新型治疗策略提供了方向，该策略可通过调控微小RNA表达水平用于乳腺癌的治疗。本研究通过对稳定表达靶向核仁素的双链（ds）干扰RNA或乱序序列对照双链干扰RNA（sh-NCL或sh-Scr）的HeLa细胞进行微小RNA高通量测序，鉴定出受核仁素调控的微小RNA。