Purpose: This study aimed to investigate the correlation of long non-coding RNA (lncRNA) TCONS_l2_00002973 expression with clinicopathological features as well as overall survival (OS) in triple-negative breast cancer (TNBC) patients, and further explore the regulatory effect of lncRNA TCONS_l2_00002973 on cells' proliferation and apoptosis in TNBC cells.
Methods: 96 TNBC patients undergoing surgery were consecutively enrolled in this prospective cohort study. LncRNA TCONS_l2_00002973 expression in tumor tissue sample and adjacent non-tumor sample was detected by qPCR. Normal control (NC) shRNA (NC(-) group), lncRNA TCONS_l2_00002973 shRNA (Lnc(-) group), NC overexpression (NC(+) group) and lncRNA TCONS_l2_00002973 overexpression plasmids (Lnc(+) group) were transfected into MDA-MB-231 breast cancer cells. Cell proliferation ability, cell apoptosis rate and apoptosis-related protein expressions were detected using CCK-8 assay, annexin V (AV)/propidium iodide (PI) assay and Western blot assay respectively.
Results: LncRNA TCONS_l2_00002973 expression was lower in tumor tissue compared to paired adjacent tissue (p<0.001), and its low expression was associated with increased T stage (p=0.002), raised N stage (p=0.003) and advanced TNM stage (p=0.005) in TNBC patients. Poor OS was found in lncRNA TCONS_l2_00002973 low expression group compared to lncRNA TCONS_l2_00002973 high expression group (p=0.006). Further in vitro experiments disclosed that lncRNA TCONS_l2_00002973 expression was reduced in various breast cancer cell lines compared to normal breast cell line, and lncRNA TCONS_l2_00002973 repressed cell proliferation and enhanced cells apoptosis in MDA-MB-231 cells.
Conclusions: LncRNA TCONS_l2_00002973 correlates with less advanced tumor stage and favorable survival, and it also inhibits cancer cells proliferation while enhances apoptosis in TNBC.