Abstract
DLG1-AS1 and PBX3 have been identified as acting as an oncogene in cervical cancer. However, they have not been well explored in triple-negative breast cancer (TNBC). As TNBC is one of the malignancies causing increasing death throughout the world, this study aimed to probe into the regulatory relationship between DLG1-AS1 and PBX3 in TNBC cells. In this study, real-time quantitative PCR (qRT-PCR) and western blot experiments were conducted to investigate the RNA and protein levels of genes of interest in TNBC cells. Functional experiments were implemented, such as 5-ethynyl-2'-deoxyuridine (EdU), transwell, and wound healing assays, to assess the changes in TNBC cell phenotype. Chromatin immunoprecipitation, luciferase reporter, RNA binding protein immunoprecipitation, and RNA pull-down assays were conducted to investigate the binding relationships among subject genes. The results show that DLG1-AS1 and PBX3 displayed high expression in TNBC cells, and PBX3 worked as the transcriptional activator of DLG1-AS1. Also, DLG1-AS1 served as an oncogene in TNBC cells and as a sponge for miR-16-5p to up-regulate JARID2. Meanwhile, JARID2 and PBX3 exerted oncogenic effects on TNBC cell growth. In conclusion, PBX3-activated DLG1-AS1 can promote the proliferation, invasion, and migration of TNBC cells by sponging miR-16-5p and elevating JARID2 expression.