Breast cancer (BC) is a common cancer with poor survival. This study aimed to explore the effect of miR-940 on the process of BC cells and its target gene FOXO3. The expression of miR-940 was assessed in BC tissues and cells using qRT-PCR. Furthermore, the correlation between miR-940 and prognosis of BC patients from the TCGA database was analyzed. CCK8 assays and colony formation assays were used to explore the effect of miR-940 on BC cell proliferation. The invasion abilities were detected by transwell assays. Luciferase reporter assay was performed to scrutinize the relationship between miR-940 and FOXO3. Finally, rescue experiments were performed through FOXO3 downregulation and miR-940 inhibitors by using CCK8 assays, colony formation assays and transwell assays. miR-940 was significantly upregulated in BC cells and tissues. In addition, the high level of miR-940 correlated with poor survival of BC patients (P=0.023). CCK8 assays, colony formation assays and transwell assays indicated that miR-940 promoted the proliferation and invasion abilities of BC cells. The luciferase reporter assay suggested that miR-940 directly targeted FOXO3. Moreover, we found that the effect of si-FOXO3 was rescued by miR-940 inhibitor in BC cells. miR-940 may promote the proliferation and invasion abilities of BC cells by targeting FOXO3. Our study suggested that miR-940 could be a novel molecular target for therapies against BC.

中文翻译：

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MiR-940通过调节FOXO3促进乳腺癌的恶性进展。

乳腺癌（BC）是存活率低的常见癌症。这项研究旨在探讨miR-940对BC细胞及其靶基因FOXO3的作用。使用qRT-PCR评估miR-940在BC组织和细胞中的表达。此外，从TCGA数据库分析了miR-940与BC患者预后之间的相关性。使用CCK8测定和集落形成测定来探索miR-940对BC细胞增殖的影响。通过transwell测定法检测侵袭能力。进行荧光素酶报告基因分析以检查miR-940和FOXO3之间的关系。最后，通过使用CCK8分析，菌落形成分析和transwell分析，通过FOXO3下调和miR-940抑制剂进行了拯救实验。miR-940在BC细胞和组织中显着上调。此外，miR-940的高水平与BC患者生存率低有关（P = 0.023）。CCK8测定，集落形成测定和transwell测定表明，miR-940促进了BC细胞的增殖和侵袭能力。荧光素酶报告基因测定表明miR-940直接靶向FOXO3。此外，我们发现，miR-940抑制剂在BC细胞中拯救了si-FOXO3的作用。miR-940可通过靶向FOXO3促进BC细胞的增殖和侵袭能力。我们的研究表明，miR-940可能是针对BC治疗的新型分子靶标。荧光素酶报告基因测定表明miR-940直接靶向FOXO3。此外，我们发现，miR-940抑制剂在BC细胞中拯救了si-FOXO3的作用。miR-940可通过靶向FOXO3促进BC细胞的增殖和侵袭能力。我们的研究表明，miR-940可能是针对BC治疗的新型分子靶标。荧光素酶报告基因测定表明miR-940直接靶向FOXO3。此外，我们发现，miR-940抑制剂在BC细胞中拯救了si-FOXO3的作用。miR-940可通过靶向FOXO3促进BC细胞的增殖和侵袭能力。我们的研究表明，miR-940可能是针对BC治疗的新型分子靶标。