结直肠癌（CRC）是癌症相关死亡的主要原因之一。反义RNA（asRNA）与癌症的恶性变化密切相关。本研究旨在揭示asRNA在控制CRC恶性变化中的作用机制。对RNA测序数据的分析表明，AFAP1-AS1和MLK7-AS1在CRC患者和细胞系中上调表达。高水平的这两种asRNA与CRC患者的预后不良有关。体外和体内实验表明，抑制这两种asRNA可以降低CRC细胞的增殖和转移能力。机制学上，AFAP1-AS1和MLK7-AS1通过作为ceRNA降低了miR-149-5p和miR-485-5p的水平。通过引入miRNA模拟子，miRNA的过表达直接与SHMT2和IGFBP5的mRNA的3' UTR结合，抑制它们的表达。抑制这两种asRNA可以降低SHMT2和IGFBP5的表达，而miRNA抑制剂对这两种miRNA的抑制可以逆转该效应。通过使用载荷有小干扰RNA的纳米粒子对asRNA进行体内药理靶向，结果显示抑制asRNA可以显著减少肿瘤的生长和转移。我们的研究结果表明，AFAP1-AS1和MLK7-AS1通过吸附抑制性miRNA miR-149-5p和miR-485-5p来促进CRC的发展，从而上调SHMT2和IGFBP5的表达。© 2023 作者

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths. Antisense RNAs (asRNAs) are closely associated with cancer malignancy. This study aimed to identify the action mechanism of asRNAs in controlling CRC malignancy. Analysis of the RNA sequencing data revealed that AFAP1-AS1 and MLK7-AS1 were upregulated in CRC patients and cell lines. High levels of both asRNAs were associated with poor prognosis in patients with CRC. Both in vitro and in vivo experiments revealed that the knockdown of the two asRNAs decreased the proliferative and metastatic abilities of CRC cells. Mechanistically, AFAP1-AS1 and MLK7-AS1 decreased the levels of miR-149-5p and miR-485-5p by functioning as ceRNAs. Overexpression of miRNAs by introducing miRNA mimics suppressed the expression of SHMT2 and IGFBP5 by directly binding to the 3' UTR of their mRNA. Knockdown of both asRNAs decreased the expression of SHMT2 and IGFBP5, which was reversed by inhibition of both miRNAs by miRNA inhibitors. In vivo pharmacological targeting of both asRNAs by small interfering RNA-loaded nanoparticles showed that knockdown of asRNAs significantly reduced tumor growth and metastasis. Our findings demonstrate that AFAP1-AS1 and MLK7-AS1 promote CRC progression by sponging the tumor-suppressing miRNAs miR-149-5p and miR-485-5p, thus upregulating SHMT2 and IGFBP5.© 2023 The Author(s).