Objective:To investigate the expression of Per2 mRNA, HDAC1 mRNA and E-cadherin mRNA in esophageal cancer cells and their significance.Methods:The experimental study was conducted. Human normal esophageal epithelial cells as the control group and human esophageal cancer cell line KYSE-150 cells as the experimental group were cultured in vitro to logarithmic growth stage. Observation indicators: (1) the proliferation of cells; (2) the migration and invasion of cells; (3) the expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA in cells of initial physiological state; (4) the expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA after cells were treated with Per2-agonists or inhibitors; (5) the expression of Per2 mRNA and E-cadherin mRNA after cells were treated with HDAC1 inhibitors. Measurement data with normal distribution were represented as Mean± SD, the t test was used for comparison within groups and the t test or ANCOVA were used for comparison between groups. Results:(1) The proliferation of cells: the cell proliferation of the experimental group and control group were 0.90%±0.14% and 0.52%±0.08%, with a significant difference between the two groups ( t=5.166, P<0.05). (2) The migration and invasion of cells: the numbers of cell migration and invasion for the experimental group were 173±41 and 86±27, versus 50±15 and 21±9 for the control group, with significant differences between the two groups ( t=6.274, 5.153, P<0.05). (3) The expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA in cells of initial physiological state: the expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA in cells of initial physiological state for the experimental group was 11.7±2.7, 20.4±6.6, and 12.4±2.5, respectively, versus 2.4±0.5, 8.5±2.2, and 27.3±4.5 for the control group, with significant differences between the two groups ( t=5.782, 2.982, -5.034, P<0.05). (4) The expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA after cells were treated with Per2-agonists or inhibitors: after cells were treated with Per2-agonists, the expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA were 13.1±2.2, 22.4±6.2, 16.6±4.2 for the experimental group, and 9.9±3.1, 18.4±5.6, 15.3±2.3 for the control group, respectively. There was no significant difference in the expression of Per2 mRNA, HDAC1 mRNA, or E-cadherin mRNA of the experimental group between cells being treated with and without Per2-agonists ( t=-4.300, 10.087, -4.187, P>0.05). There were significant differences in the expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA of the control group between cells being treated with and without Per2-agonists ( t=-4.846, 3.501, 9.294, P<0.05). There was no significant difference in the expression of Per2 mRNA or E-cadherin mRNA between the experimental group and control group after cells were treated with Per2-agonists ( F=1.000, 7.582, P>0.05), while there was a significant difference in the expression of HDAC1 mRNA between the two groups ( F=1.724, P<0.05). After cells were treated with Per2-inhibitors, the expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA were 4.1±1.7, 7.5±2.2, 22.8±4.2 for the experimental group, and 3.1±0.9, 9.3±3.2, 28.4±5.8 for the control group, respectively. There were significant differences in the expression of Per2 mRNA, HDAC1 mRNA, and E-cadherin mRNA of the experimental group between cells being treated with and without Per2-inhibitors ( t=12.124, 5.105, -10.245, P<0.05). There was no significant difference in the expression of Per2 mRNA, HDAC1 mRNA, or E-cadherin mRNA of the control group between cells being treated with and without Per2-inhibitors ( t=-2.815, 1.568, -1.439, P>0.05). There were significant differences in the expression of Per2 mRNA and E-cadherin mRNA after cells were treated with Per2-inhibitors between the experimental group and control group ( F=22.965, 82.134, P<0.05), while there was no significant difference in the expressions of HDAC1 mRNA between the two groups ( F=6.416, P>0.05). (5) The expression of Per2 mRNA and E-cadherin mRNA after cells were treated with HDAC1 inhibitors: after cells were treated with HDAC1 inhibitors, the expression of Per2 mRNA and E-cadherin mRNA were 13.4±3.5, 24.2±3.4 for the experimental group, and 3.1±1.2, 26.8±5.2 for the control group, respectively. There was no significant difference in the expression of Per2 mRNA of the experimental group between cells being treated with and without HDAC1-inhibitors ( t=-3.959, P>0.05). There was a significant difference in the expression of E-cadherin mRNA of the experimental group between cells being treated with and without HDAC1-inhibitors ( t=-21.977, P<0.05). There was no significant difference in the expression of Per2 mRNA or E-cadherin mRNA of the control group between cells being treated with and without HDAC1-inhibitors ( t=-1.440, 1.058, P>0.05). After cells were treated with HDAC1-inhibitors, there was no significant difference in the expressions of Per2 mRNA between the experimental group and control group ( F=2.004, P>0.05), while there was a significant difference in the expression of E-cadherin mRNA between the two groups ( F=325.800, P<0.05). Conclusions:Human esophageal cancer cells have an elevated expression of Per2 mRNA and HDAC1 mRNA, and a reduced expression of E-cadherin mRNA. The overexpression of Per2 mRNA may activate the expression of downstream targeting protein HDAC1, and inhibit the expression of cell surface E-cadherin mRNA.