Effect Of Down-regulation Of SMYD3 Expression By RNAi On Histone 3 Lysine 4 Tri-methylation Of Esophageal Squamous Cell Carcinoma

Object: To investigate the expression of histone 3 lysine 4(H3K4) tri-methylation in esophageal squamous cell carcinoma tissues and esophageal normal tissues, to evalue the role of H3K4 tri-methylation in the development of esophageal squamous cell carcinoma; to verify the inhibitory function of SMYD3-si RNA in SMYD3 expression; to explore the effect of SMYD3 down-regulation on the expression of H3K4 tri-methylation.Method: 1. 14 groups of tissues including cancer and normal esophagus tissues were got from surgery, histone was extraceted to observe the quantity of H3K4 tri-methylation by ELISA. 2. 3 groups of SMYD3-si RNA(si RNA-440, si RNA-936, si RNA-1232), 1 group of ineffective si RNA and 1 group of positive control were designed and synthesized which were transfected into TE13 cells. SMYD3 m RNA and protein expression levels were measured in order to select the most efficient si RNA. After SMYD3 was down-regulated in esophageal squamous carcinoma TE13 cells, the quantity of H3K4 tri-methylation were measured by ELISA.Result: 1. The ELISA result showed that: in all the 14 groups, the quantity of H3K4 tri-methylation was observed; The quantity of H3K4 methylation in the cancer tissues were higher than that in in the adjacent tissues( p<0.05). 2. 3 groups of SMYD3-si RNA were constructed successfully. The m RNA and protein expression levels of SMYD3 were significantly decreased by RNA interference(p<0.05). The SMYD3-si RNA-936 was the most effective si RNA. There was statistically significant difference compared with other groups(p<0.05). Compared with the negative control group and the blank control group, after the transfection with SMYD3-si RNA-936, the quantity of H3K4 tri-methylation in the TE13 cells were significantly decreased(p<0.05).Conclusion: 1. H3K4 tri-methylation maybe participate in the normal physiological activities of cells due to the presence in both groups of tissues. But the quantity of H3K4 tri-methylation in the esophageal squamous cell carcinoma tissues was significantly higher than that in esophageal adjacent tissues, as a result, increasing the quantity of of H3K4 tri-methylation has a correlation with the occurrence of esophageal squamous cell carcinoma. 2. si RNA can efficiently down-regulate SMYD3 gene in esophageal squamous carcinoma TE13 cells, which offers an establishment of SMYD3-interfered cells-test-model for experiments in the future. In terms of SMYD3, RNAi should be a potential method for gene therapy and gene research. After the expression of SMYD3 was significantly decreased by RNAi in TE13 cells, the H3K4 tri-methylation expression level was significantly decreased. SMYD3 may participate in the physiological activities of esophageal squamous carcinoma through regulating the tri-methylation of H3K4.