β-Elemene inhibits the proliferation of esophageal squamous cell carcinoma by regulating long noncoding RNA-mediated inhibition of hTERT expression.

The study aimed to clarify the relationship between β-elemene, a long noncoding RNA (lncRNA), and human telomerase reverse transcriptase (hTERT) in esophageal carcinoma ECA-109 cells. The proliferation of ECA-109 cells was measured using a CCK-8 kit and flow cytometry. PCR microarray and real-time RT-PCR were designed to determine lncRNA expression in ECA-109 cells before and after treatment with β-elemene. Western blot was used to detect the hTERT level after the differentially expressed lncRNAs in ECA-109 cells were interfered with small interfering RNA (siRNA). On treatment with β-elemene, the proliferation of ECA-109 cells was notably inhibited, and about 85% of the lncRNAs showed higher expression levels in ECA-109 cells than in those untreated cells, from which, CDKN2B-AS1 was screened out. A specific siRNA (si-CDKN2B-AS1) that targets the β-elemene-mediated lncRNA CDKN2B-AS1 was designed, synthesized, and applied to treat ECA-109 cells. Its interference efficiency reached as high as 89.6%. When ECA-109 cells were transfected with the siRNA, the hTERT level was increased by 84.7%. The CCK-8 assay showed that the proliferation of ECA-109 cells treated with β-elemene was significantly promoted after siRNA transfection (P<0.01). It was also shown by flow cytometry that, compared with the scramble-treated group (negative control), the proliferation index value of ECA-109 cells in the si-CDKN2B-AS1 treatment group was notably increased (25.7 vs. 51.7%) and the TERT protein level was increased by 67.25% after the cells were treated with si-CDKN2B-AS1. The chemotherapeutic drug β-elemene suppressed the proliferation of esophageal carcinoma ECA-109 cells by regulating the inhibition of hTERT expression by lncRNA CDKN2B-AS1.