Background: To improve the prognosis of patients with lung adenocarcinoma (LUAD), revolutionary treatments for metastatic lesions are essential.Methods: To identify genes closely involved in LUAD-cell-derived metastasis, we used RNA sequencing to generate microRNA (miRNA) expression signatures of brain metastatic lesions. Once tumor-suppressive miRNAs are identified, it will be possible to explore the numerous tumor-promoting genes that are regulated by miRNAs.Results: By comparison with a previously created LUAD signature, we identified several miRNAs whose expression was significantly suppressed in brain metastases. We focused on both strands of pre-miR-195(miR-195-5pandmiR-195-3p), which were significantly downregulated in brain metastatic tissues, and confirmed by ectopic expression assays that both strands of pre-miR-195attenuated the aggressive phenotypes (cell proliferation, migration, and invasion) of LUAD cells. These data suggest that both strands of pre-miR-195have tumor-suppressive functions in LUAD cells. Next, we explored the target molecules that each miRNA strand regulates in LUAD cells. We identified 159 target genes regulated bymiR-195-5pandmiR-195-3p, of which 12 genes (ANLN,CDC6,CDCA2,CDK1,CEP55,CHEK1,CLSPN,GINS1,KIF23,MAD2L1,OIP5, andTIMELESS) affect cell cycle/cell division and the prognosis of LUAD patients. Finally, we focused on two genes,ANLN(miR-195-5ptarget) andMAD2L1(miR-195-3ptarget), and demonstrated their oncogenic functions and the molecular pathways they regulate in LUAD cells.Conclusions: The miRNA signature derived from lung cancer brain metastasis will be a landmark in the field, and analysis of this miRNA signature will accelerate the identification of genes involved in lung cancer brain metastasis.
背景：为改善肺腺癌（LUAD）患者预后，针对转移性病灶的革新性治疗至关重要。方法：为识别与肺腺癌细胞源性转移密切相关的基因，我们采用RNA测序技术构建了脑转移病灶的microRNA（miRNA）表达谱。通过鉴定具有肿瘤抑制功能的miRNA，可进一步探索受miRNA调控的众多促癌基因。结果：通过与既往建立的肺腺癌表达谱对比，我们发现在脑转移灶中多个miRNA表达显著受抑制。研究聚焦于前体miR-195的双链（miR-195-5p与miR-195-3p），其在脑转移组织中显著下调。异位表达实验证实，前体miR-195双链均能抑制肺腺癌细胞的侵袭性表型（细胞增殖、迁移和侵袭），提示二者在肺腺癌细胞中均具有肿瘤抑制功能。随后我们探究了各miRNA链在肺腺癌细胞中调控的靶分子，共鉴定出159个受miR-195-5p和miR-195-3p调控的靶基因，其中12个基因（ANLN、CDC6、CDCA2、CDK1、CEP55、CHEK1、CLSPN、GINS1、KIF23、MAD2L1、OIP5及TIMELESS）可影响细胞周期/细胞分裂并关联肺腺癌患者预后。最终我们聚焦于ANLN（miR-195-5p靶点）和MAD2L1（miR-195-3p靶点）两个基因，证实了它们在肺腺癌细胞中的致癌功能及其调控的分子通路。结论：源自肺癌脑转移的miRNA表达谱将成为该领域的里程碑，对此表达谱的分析将加速肺癌脑转移相关基因的鉴定进程。
肿瘤(癌症)患者之家