Influence Of Down-regulation Of REG4Expression By Small Interfering RNA On Biological Behavior Of Gastric Cancer Cells

Objective REG4(regenerating islet-derived family, member4, REG4)is compsed of17496bp,six exons and five introns. The gene of Reg IV is located at1p12-13.1.Itencodes small secreted protein RegIV which is also named RELP(reg-like protein,RELP).Studies have shown that the expression of REG4is abnormal when people aresuffering from gastric, colon, pancreas and other gastrointestinal tumors. Ourobjective is to investigate the influence of down-regulation of REG4expression bysmall interfering RNA on biological behavior of gastric cancer cells.Methods In order to futher clarify the relation between the expressional level ofREG4and biological behaviorof gastric cancer cells,3small interfering RNA(siRNA1, siRNA2, siRNA3) targeting REG4were designed and transfected intogastric cancer cell lines. As a result, we gained cells that are silent in REG4expression, which belong to AGS cell lines. The effect of interference on REG4’sexpression on proliferation, apoptosis, migration and invasion of AGS cell weresystematically analyzed.Results Experimental results showed that siRNA2and siRNA3notablydown-regulated expression of REG4mRNA levels in contrast to that in control group.Therefore siRNA3was used in cell proliferation assay. After transfection of siRNA3,the proliferation of AGS cell significantly decreased compared with the controlgroup(Ｐ＜0.05). The results of flow cytometry revealed that transfection withsiRNA3causes the apoptosis rate of AGS significantly increased(Ｐ＜0.05). Resultsof scratches healing assay indicated that migratory speed of the cell was slower aftertransfection of siRNA3.Results of Transwell invasion assay also showed that whenexpression of REG4was interfered, the number of the cells that cross matrix gel wasalso decreased significantly(Ｐ＜0.05).Conclusion All of these results suggest that interfering and down regulating REG4 gene can inhibit proliferation、migration、invasion as well as promote apoptosis ofgastric cancer cells, indicating that REG4gene is probably a target for gastric cancergene therapy.