Effects of Down-regulation of HDAC6 Expression on Proliferation,Cell Cycling and Migration of Esophageal Squamous CellCarcinoma Cells and Related Molecular Mechanisms

Objective: To study the effects of down-regulation of HDAC6 expression on proliferation, cell cycling andmigration of esophageal squamous cell carcinoma (ESCC) cells and related molecular mechanisms.
Methods:ESCC cell line EC9706 cells were randomly divided into untreated (with no transfection), control siRNA(transfected with control siRNA) and HDAC6 siRNA (transfected with HDAC6 small interfering RNA) groups.Effects of HDAC6 siRNA interference on expression of HDAC6 mRNA and protein in EC9706 cells wereinvestigated by semi-quantitative RT-PCR, Western blotting and immunocytochemistry methods. Effects ofdown-regulation of HDAC6 expression on cell proliferation, cell cycle, and cell migration were studied usinga CCK-8 kit, flow cytometry and Boyden chambers, respectively. Changes of mRNA and protein expressionlevels of cell cycle related factor (p21) and cell migration related factor (E-cadherin) were investigated by semiquantitativeRT-PCR and Western blotting methods.
Results: After transfection of HDAC6 siRNA, the expressionof HDAC6 mRNA and protein in EC9706 cells was significantly downregulated. In the HDAC6 siRNA group,cell proliferation was markedly inhibited, the percentage of cells in G0/G1 phase evidently increased and thepercentage of cells in S phase decreased, and the number of migrating cells significantly and obviously decreased.The mRNA and protein expression levels of p21 and E-cadherin in the HDAC6 siRNA group were significantlyhigher than those in the untreated group and the control siRNA group, respectively.
Conclusions: HDAC6 siRNAcan effectively downregulate the expression of HDAC6 mRNA and protein in EC9706 cells. Down-regulation ofHDAC6 expression can obviously inhibit cell proliferation, arrest cell cycling in the G0/G1 phase and reduce cellmigration. The latter two functions may be closely related with the elevation of mRNA and protein expressionof p21 and E-cadherin.