Wenbo Tang, Xinyang Liu, MinjunWang, Jin Li

Department of MedicalOncology, Fudan University Shanghai Cancer Center

Objective:To investigate the expression ofmicroRNA-425-5p in gastric cancer patients' specimens and cell lines; Toinvestigate the up-regulation and down-regulation of microRNA-425-5p on gastriccancer cell proliferation, migration and invasion; To investigate the targetgene and mechanism of microRNA-425-5p in mediation gastric cancer cellproliferation, migration and invasion. Method: Data from TCGA databaseand real-time PCR were used to assess the expression ofmicroRNA-425-5p ingastric cancer tissues and cell lines. MiRNA mimics and inhibitor were used forup-regulation and down-regulation of microRNA-425-5p in GC cells. Cell countingkit-8 was used to measure cell proliferation, and migration and invasion assayswere used to investigate the migration and invasion ability of GC cells.Prediction of target genes were done by TargetScan, miRanda and Pictar tools.Real-time PCR and Western blot were adopted to investigate the change of ZNF24when altering the expression of microRNA-425-5p in GC cells. Luciferasereporter gene system and luciferase assay were used in comfirming the targetgenes. Real-time PCR were used to detect the mRNA level of ZNF24 in 75 clinicalGC tissue samples with adjacent normal tissue samples and analyse theprognostic role of ZNF24 in gastric cancer. Cotransfection of microRNA-425-5pmimics and ZNF24 overexpression plasmid was used to confirm that ZNF24 isinvolved in microRNA-425-5p promoted proliferation, migration and invasion ofGC cells. Result: Data from TCGA indicated that a significantlyincreased level of microRNA-425-5p in GCs compared with corresponding non-tumortissues. The normal gastric membrane cell line GES-1 showed a relatively lowexpression of microRNA-425-5p. MGC803 and SGC7901 cells were chosen as tools.Overexpression of microRNA-425-5p significantly promoted, while knockdownsupressed the proliferation, migration and invasion abilities of GC cells.TargetScan, miRanda and Pictar analyses indicated ZNF24 as a potential targetgene. Relatively high ZNF24 expression was shown in GES-1 cells. PCR andwestern blot indicated decreased expression of ZNF24 in microRNA-425-5poverexpression cancer cells. Luciferase assay further confirmed thatmicroRNA-425-5p down regulated ZNF24 expression by directly targeting its3'UTR. Significantly higher level of ZNF24 was detected in non-tumor tissuesthan corresponding tumor samples. Overexpressionof ZNF24 would decrease theproliferation, migtation and invaison abilities of GC cells. Conclusion: Ourfindings demonstrate that microRNA-425-5p promoted GC cell proliferation,migration and invasion by directly and functionally repressing the expressionof ZNF24.

Key Words: gastric cancer  microRNA-425-5p  ZNF24