To explore the mechanism of inhibiting invasion and epithelial mesenchymal transformation of esophageal squamous cell carcinoma cells by chidamide (CHI) through long noncoding RNA (LncRNA) VPS9D1-AS1.

Human normal esophageal epithelial cells (HEEC) group (HEEC were cultured normally without any treatment), human esophageal squamous cell carcinoma KYSE-450 cells were divided into KYSE-450 group (normal culture), CHI group (treated with 20 μmol·L^-1 CHI for 48 h), CHI+oe-NC group (transfected with oe-NC, treated with 20 μmol·L^-1 CHI for 48 h), CHI+oe-LncRNA VPS9D1-AS1 group (transfected with oe-LncRNA VPS9D1-AS1, treated with 20 μmol·L^-1 CHI for 48 h). The positive expression of LncRNA VPS9D1-AS1 in the cells was detected by fluorescence in situ hybridization, the invasion ability of the cells was detected by Transwell, and the epithelial mesenchymal transformation and mitogen-activated protein kinase (MEK)/extracellular signal-related protein kinase (ERK) signaling pathway related protein expression levels were detected by protein Western blot.

The positive expression levels of LncRNA VPS9D1-AS1 in HEEC group, KYSE-450 group and CHI group were 1.00±0.06, 4.58±0.84 and 1.93±0.37, respectively. Compared with HEEC group and KYSE-450 group, compared with CHI group and KYSE-450 group, the positive expression levels of LncRNA VPS9D1-AS1 were significantly different (P<0.05). The invasion numbers of cells in KYSE-450 group, CHI group, CHI+oe-NC group, CHI+oe-LncRNA VPS9D1-AS1 group were 89.57±15.61, 22.49±5.18, 27.04±5.95 and 57.82±10.73, respectively; the relative expression levels of N-cadherin were 1.00±0.07, 0.52±0.12, 0.59±0.09 and 0.91±0.16, respectively; the relative expression levels of E-cadherin were 1.00±0.11, 1.81±0.35, 1.79±0.30 and 1.24±0.22, respectively; the relative expression levels of MEK1 were 1.00±0.08, 0.64±0.11, 0.69±0.13 and 0.93±0.17, respectively; p-ERK1/ERK1 levels were 1.00±0.05, 0.61±0.07, 0.55±0.10 and 0.95±0.15, respectively; p-ERK2/ERK2 levels were 1.00±0.12, 0.43±0.09, 0.42±0.08 and 0.89±0.14, respectively. Compared between KYSE-450 group and CHI group, between CHI+oe-LncRNA VPS9D1-AS1 group and CHI+oe-NC group, there were statistical significance in the levels of the above indexes (P<0.05).

CHI can inhibit esophageal squamous cell invasion and epithelial mesenchymal transformation, which may be related to the inhibition of MEK/ERK signaling pathway activation by LncRNA VPS9D1-AS1 down-regulated by CHI.