Effect and prognostic significance of the KAI1 gene in human gastric carcinoma

The present study aimed to explore the effect and mechanism of the Kangai 1 (KAI1) gene in regulating the migration and invasion of gastric carcinoma cells, and the prognostic significance of this gene in gastric cancer patients. Immunohistochemistry and in situ hybridization were used to investigate the role of KAI1 in the progression and prognosis of gastric cancer. The pEGFP-N1-KAI1 plasmid was transfected into human gastric carcinoma SGC7901 cells using liposomes. The effect of transfection with the KAI1 gene was measured using a reverse transcription-semi-quantitative polymerase chain reaction (RT-sqPCR) assay. The Transwell chamber assay was used to study the metastatic and invasive ability of SGC7901 cells. Gastric cancer metastasis-associated genes, including hypoxia-inducible factor (HIF)-1α, matrix metalloproteinase (MMP)-2, MMP-9, basic fibroblast growth factor (bFGF), and urease plasminogen activator (uPA) were measured by RT-sqPCR prior to and following transfection with the KAI1 gene. The expression of KAI1 protein and mRNA was associated with the differentiation degree of gastric cancer, presence of lymph node metastasis, tumor-node-metastasis stage, depth of invasion and the survival time of patients. The migratory and invasive abilities of SGC7901 cells were significantly decreased subsequent to transfection with the KAI1 gene, and the expression of bFGF and uPA was downregulated. It was concluded that the tumor suppressor gene KAI1 inhibits the migration and invasion of gastric carcinoma cells, possibly by suppressing the expression of uPA. Patients that expressed KAI1 may demonstrate an improved prognosis.