Department of Breast Surgery, Peking Union Medical College Hospital, Peking Union Medical College &Chinese Academy of Medical Sciences (CAMS), Beijing, China.
Sci Rep. 2020 May 6;10(1):7662. doi: 10.1038/s41598-020-64713-x.
The actin fiber-associated protein 1-antisense RNA1 (AFAP1-AS1) is upregulated in various cancers and associated with cancer proliferation and metastasis. Several cancer-related pathways have been linked to up-expression of this long non-coding (lnc)RNA, but the underlying mechanisms are yet unknown. In triple negative breast cancer (TNBC), AFAP1-AS1 expression is also significantly overexpressed compared to that in other subtypes of breast cancer from the TCGA dataset. In this study, we performed bioinformatic RNAhybrid analyses and identified that miR-145 is a potential target of AFAP1-AS1 and able to reduce MutT homolog-1 (MTH1) expression. Thus, this study investigated the oncogenic activity of AFAP1-AS1 in TNBC cells and the underlying mechanisms that are yet poorly understood. The results showed that miR-145 expression was low, whereas AFAP1-AS1 and MTH1 expression was high in TNBC cells and that miR-145 mimics reduced TNBC cell proliferation and invasion, whereas miR-145 knockdown exerted the opposite activity in TNBC cells. Moreover, knockdown of AFAP1-AS1 reduced tumor cell proliferation and invasion, but miR-145 co-transfection rescued tumor cell viability and colony formation ability. The dual luciferase reporter assay showed that AFAP1-AS1 could directly target miR-145, while miR-145 could directly target MTH1. After knockdown of ATF6, AFAP1-AS1 was reduced along with AFAP1-AS1 promoter activity. This study revealed that AFAP1-AS1 could promote TNBC cell proliferation and invasion via regulation of MTH1 expression through targeting of miR-145.
肌动蛋白纤维相关蛋白 1-反义 RNA1（AFAP1-AS1）在各种癌症中上调，与癌症增殖和转移有关。几种与癌症相关的途径与这种长非编码（lnc）RNA 的上调有关，但潜在的机制尚不清楚。在三阴性乳腺癌（TNBC）中，与 TCGA 数据集中其他乳腺癌亚型相比，AFAP1-AS1 的表达也明显过表达。在这项研究中，我们进行了生物信息学 RNAhybrid 分析，确定 miR-145 是 AFAP1-AS1 的潜在靶标，能够降低 MutT 同源物-1（MTH1）的表达。因此，本研究调查了 AFAP1-AS1 在 TNBC 细胞中的致癌活性及其潜在的机制尚不清楚。结果表明，miR-145 表达较低，而 AFAP1-AS1 和 MTH1 表达较高在 TNBC 细胞中，miR-145 模拟物降低了 TNBC 细胞的增殖和侵袭，而 miR-145 敲低则在 TNBC 细胞中发挥相反的作用。此外，AFAP1-AS1 的敲低降低了肿瘤细胞的增殖和侵袭，但 miR-145 的共转染挽救了肿瘤细胞的活力和集落形成能力。双荧光素酶报告基因检测显示，AFAP1-AS1 可以直接靶向 miR-145，而 miR-145 可以直接靶向 MTH1。在敲低 ATF6 后，AFAP1-AS1 减少，同时 AFAP1-AS1 启动子活性降低。本研究表明，AFAP1-AS1 可以通过靶向 miR-145 调节 MTH1 表达来促进 TNBC 细胞的增殖和侵袭。
