MicroRNAs (miRNAs) play important roles in the development of various cancers including lung cancer which is one of the devastating diseases worldwide. How miRNAs function in de novo lung tumorigenesis remains largely unknown. We here developed a CRISPR/Cas9-mediated dual guide RNA (dgRNA) system to knockout miRNAs in genetically engineered mouse model (GEMM). Through bioinformatic analyses of human lung cancer miRNA database, we identified 16 downregulated miRNAs associated with malignant progression and performed individual knockout with dgRNA system in Kras^G12D/Trp53^L/L (KP) mouse model. Using this in vivo knockout screening, we identified miR-30b and miR-146a, which has been previously reported as tumor suppressors and miR-190b, a new tumor-suppressive miRNA in lung cancer development. Over-expression of miR-190b in KP model as well as human lung cancer cell lines significantly suppressed malignant progression. We further found that miR-190b targeted the Hus1 gene and knockout of Hus1 in KP model dramatically suppressed lung tumorigenesis. Collectively, our study developed an in vivo miRNA knockout platform for functionally screening in GEMM and identified miR-190b as a new tumor suppressor in lung cancer.

MicroRNA（miRNA）在包括肺癌在内的各种癌症的发展中起着重要作用，而肺癌是全世界范围内的毁灭性疾病之一。miRNA在新生肺肿瘤发生过程中如何发挥作用尚不清楚。我们在这里开发了一种CRISPR / Cas9介导的双向导RNA（dgRNA）系统，以敲除基因工程小鼠模型（GEMM）中的miRNA。通过人类肺癌miRNA数据库的生物信息学分析，我们在Kras ^G12D / Trp53 ^{L / L}（KP）小鼠模型中鉴定了16个与恶性进展相关的下调的miRNA，并用dgRNA系统进行了基因敲除。使用这种在体内在基因敲除筛选中，我们鉴定了miR-30b和miR-146a（先前已报道为抑癌剂）和miR-190b（miRNA-190b，一种在肺癌发展中抑制肿瘤的新miRNA）。miR-190b在KP模型以及人类肺癌细胞系中的过表达显着抑制了恶性进展。我们进一步发现的miR-190B针对性的HUS1基因和基因敲除的HUS1在KP模型显着抑制肺癌的发生。总体而言，我们的研究开发了一种体内miRNA敲除平台，用于在GEMM中进行功能筛选，并确定了miR-190b是肺癌中的一种新型肿瘤抑制因子。