OBJECTIVETo screen and identify the proteins related with tumor metastasis of gastric cancer in a nude mouse model bearing orthotopic transplanted tumor.

METHODSZinc finger protein 139 (ZNF139)-specific siRNA was synthesized and transfected into gastric cancer cell line SGC7901, which was then screened by G418. ZNF139-siRNA-transfected cells, negative plasmid-transfected cells and untreated SGC7901 cells were orthotopically transplanted separately on the stomach wall of BALB/c nude mice. The primary tumors and metastatic lymph nodes were harvested to separate the proteins by 2-D fluorescence difference gel electrophoresis (2-D DIGE); after gel digestion, the differential proteins were subjected to liquid chromatography-mass spectrometry (LC-MS) for identification and their functions were analyzed. Western blotting was performed to verify the identified proteins.

RESULTSZNF139 expression was effectively inhibited in siRNA-transfected SGC7901 cells. ZNF139-siRNA-transfected cells showed obviously suppressed tumor growth with a lowered lymph node metastasis rate in nude mice compared with untreated cells and the negative control cells (P<0.05). Proteomic study with 2-D DIGE showed that fascin and hnRNPA2/B1 were down-regulated while ANXA1 was up-regulated in the primary tumors, and ANXA5 was down-regulated in the metastatic lymph nodes in ZNF139-siRNA-transfected group. Western blotting confirmed the results of proteomic analysis.

CONCLUSIONZNF139 gene may promote lymph node metastasis of gastric cancer by regulating fascin, hnRNPA2/B1, ANXA1, and ANXA5.