We aimed to investigate the potential role and regulatory mechanism of long noncoding RNA tumor-associated lncRNA expressed in chromosome 2 (TALNEC2) in breast cancer. The expression of TALNEC2 in breast cancer tissues and cells were investigated. MCF-7 and MDA-MB-231 cells were transfected with small interfering RNA (siRNA) duplexes for targeting TALNEC2 (si-TALNEC2), enhancer of zeste homolog 2 (EZH2; si-EZH2) and p57KIP2 (si-p57 KIP2 ), and their corresponding controls (si-NC). The viability, colony forming ability, cell cycle, apoptosis, and autophagy of transfected cells were assessed. The expressions of p-p38 mitogen-activated protein kinase (MAPK) and nuclear factor êB (NF-êB) pathway-related proteins were investigated. The results showed that TALNEC2 was highly expressed in breast cancer tissues and cells. Knockdown of TALNEC2 significantly inhibited the malignant behaviors of MCF-7 and MDA-MB-231 cells, including inhibiting cell viability and colony forming, arresting cell cycle at G0/G1 phase, inducing cell apoptosis, and promoting cell autophagy. EZH2 was a TALNEC2 binding protein, which was upregulated in breast cancer tissues and cells and could negatively regulate p57 KIP2 . Effects of TALNEC2 knockdown on malignant behaviors of MCF-7 cells were reversed by p57 KIP2 knockdown. The expressions of p-p38, RelA, and RelB in MCF-7 cells were decreased after knockdown of TALNEC2 or EZH2, which were reversed by knockdown of p57 KIP2 concurrently. In conclusion, TALNEC2 may play an oncogenic role in breast cancer by binding to EZH2 to target p57 KIP2 . Activation of p-p38 MAPK and NF-êB pathways may be key mechanisms mediating the oncogenic role of TALNEC2 in breast cancer. TALNEC2 may serve as a promising target in the therapy of breast cancer.
Apoptosis Autophagy