Long Non-coding RNA FOXD2-AS1 Silencing Inhibits Malignant Behaviors of Ovarian Cancer Cells Via miR-324-3p/SOX4 Signaling Axis

It is urgent to develop new therapeutic strategies for ovarian cancer (OC). Long-noncoding RNAs (lncRNAs) have participated in multiple biological processes including tumor recurrence and progression. This study aimed to determine the effects and potential regulatory mechanism of lncRNA FOXD2-AS1 in OC progression. Levels of lncRNA FOXD2-AS1 and miR-324-3p in OC tissues and cell lines were analyzed using quantitative real-time PCR (qRT-PCR). The direct target between FOXD2-AS1 or miR-324-3p was determined using bioinformatics tools and further verified by dual-luciferase reporter assay. Cell viability, apoptosis, migration, along invasion were assessed by MTT, flow cytometry, as well as Transwell assays, respectively. In addition, the levels of miR-324-3p, PCNA, MMP9, Bax, Bcl-2, and SOX4 in OC cells were evaluated using qRT-PCR and western blot assays. We observed that lncRNA FOXD2-AS1 was up-regulated while miR-324-3p was down-regulated in OC tissues and cell lines, especially in SKOV3 cells. Moreover, miR-324-3p was a direct target of lncRNA FOXD2-AS1. Meanwhile, SOX4 interacted with miR-324-3p and was negatively regulated by miR-324-3p in SKOV3 cells. Function assays confirmed that lncRNA FOXD2-AS1 silenced depressed cell proliferation, migration, and invasion while accelerating apoptosis. These functions of lncRNA FOXD2-AS1 were attenuated by miR-324-3p inhibition. Our research demonstrated that FOXD2-AS1 silencing restrained cell growth and metastasis of OC via regulating miR-324-3p/SOX4 axis, indicating that lncRNA FOXD2-AS1 could be a novel potential therapeutic target for OC.