Silencing essential meiotic endonuclease 1 inhibits the proliferation of liver cancer cells： A study of related mechanisms / 临床肝胆病杂志

ABSTRACT

ObjectiveTo investigate the expression of essential meiotic endonuclease 1 （EME1） in liver cancer tissue and its effect on the biological behavior of hepatoma cells. MethodsThe TCGA database was used to identify the differentially expressed genes between liver cancer tissue and paracancerous tissue. Immunohistochemistry and Western Blot were used to measure the expression abundance of EME1 in liver cancer tissue. A lentivirus was constructed by short hairpin RNA， and BEL-7404 cells were transfected with the lentivirus to interfere with the expression of the EME1 gene； the cells were divided into silencing group （shEME1 group） and control group （shCtrl group）. Quantitative real-time PCR and Western Blot were used to measure the mRNA and protein expression levels of EME1； Celigo Image Cytometer and MTT assay were used to measure cell proliferation rate； flow cytometry was used to observe cell cycle； Caspase 3/7 activity was used to measure cell apoptosis. The independent-samples t-test was used for comparison between two groups. ResultsTCGA results showed that the mRNA expression level of EME1 in liver cancer tissue was 18.9 times that in paracancerous tissue （t=5.00， P<0.001）， and the protein expression level of EME1 in liver cancer tissue was 7.0 times （based on immunohistochemistry： 8.4±2.6 vs 1.2±0.4， t=7.55， P<0.001） or 2.5 times （based on Western Blot： 249.0%±35.5% vs 100.0%±77.8%， t=3.02， P<0.05） that in paracancerous tissue. After lentivirus infection， compared with the shCtrl group， the shEME1 group had an mRNA expression level of EME1 reduced by 29.9% （29.9%±0.9% vs 100.0%±3.6%， t=32.82， P<0.001）， a protein expression level of EME1 reduced by 35.7% （35.7%±14.9% vs 100.0%±28.9%， t=3.42， P<0.05）， and a level of cell counting reduced by 45.1% （4 053±167 vs 8 988±477， t=16.91， P<0.001）， as well as a level of cell activity reduced to 66.9% （0.518±0.046 vs 0.774±0.022， t=8.74， P<0.001） and a level of colony forming ability reduced to 29.0% （75±6 vs 260±9， t=28.92， P<0.001）. Compared with the shCtrl group， the shEME1 group had a significant increase in the proportion of cells in G1 phase （49.9% vs 44.0%， t=8.96， P<0.001） and significant reductions in the proportion of cells in G2/M phase （15.9% vs 17.9%， t=9.13， P<0.001） and S phase （34.2% vs 38.1%， t=6.91， P<0.001）， while Caspase 3/7 activity was enhanced by 1.5 times （145.8%±5.9% vs 100.0%±2.3%， t=12.50， P<0.001）. ConclusionEME1 is highly expressed in liver cancer tissue， and silencing the EME1 gene can inhibit the proliferation of hepatoma cells and promote cell apoptosis.