The role of axon guidance factor semaphorin 6B in the invasion and metastasis of gastric cancer.

OBJECTIVE: To investigate the role of semaphorin 6B in gastric cancer invasion and metastasis. METHODS: Immunohistochemistry for semaphorin 6B was performed on gastric cancer tumour tissue samples in this retrospective study. Levels of semaphorin 6B protein and mRNA were determined in gastric cancer cell lines by Western blotting and quantitative reverse transcription-polymerase chain reaction, respectively. The human gastric cancer cell line SGC-7901 was transfected with small interfering RNA targeting semaphorin 6B; effects on cell adhesion, migration and invasion were determined by cell adhesion assay, transwell chamber migration assay and wound healing assay, respectively. RESULTS: Tumour tissue samples from 220 patients were analysed. In vivo, semaphorin 6B immunopositivity correlated with tumour differentiation, lymph node metastasis and distant metastasis but not patient age, sex or tumour stage. Semaphorin 6B gene silencing significantly suppressed adhesion, migration and invasion of gastric cancer cells in vitro. CONCLUSIONS: Semaphorin 6B is related to tumour differentiation and metastasis in vivo, and tumour cell migration, adhesion and invasion in vitro. Semaphorin 6B may represent a reliable biomarker for diagnosis, evaluation and gene-targeted therapy of gastric cancer.