LncRNA APTR as a potential prognostic biomarker for triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most invasive subtype of breast cancer (BC) with high recurrence, high mortality, poor prognosis, and a lack of effective targeted therapies. This study aimed to investigate the prognostic value of lncRNA Alu-mediated p21 transcriptional regulator (APTR) in TNBC. APTR/miR-298 levels in TNBC tissues and cell lines were detected by RT-qPCR. The correlation between APTR and the prognosis of TNBC patients was analyzed by Kaplan-Meier survival analysis. The direct binding relationship between APTR and miR-298 was verified with a luciferase reporter assay. CCK-8 and Transwell assays were conducted to elucidate the role of APTR knockdown and miR-298 co-knockdown in regulating the viability and migration of TNBC cells. APTR was upregulated in TNBC tissues and cell lines, while miR-298 was downregulated. High APTR expression was closed associated with poor prognosis of TNBC patients. Mechanistically, APTR directly binds to and negatively regulates miR-298. Functional experiments showed that knockdown of APTR significantly inhibited the viability and migration of TNBC cells, while miR-298 inhibition partially abrogated these tumor-suppressive effects. APTR is upregulated in TNBC and is closely related to poor prognosis. APTR exerts an oncogenic role in TNBC by negatively regulating miR-298, suggesting that APTR serves as a promising novel prognostic biomarker for TNBC.