Inhibition of gastric cancer cell growth, invasion and metastasis by tocotrienolic amide

Abstract

Purpose: To investigate the effect of tocotrienolic amide on gastric cancer (GC) cell growth and metastasis, and the underlying  mechanism of action.Methods: Gastric cancer (GC) cell lines MKN28 and NCI-N87 were cultured in Dulbecco's modified Eagle medium (DMEM) supplemented with 10 % fetal bovine serum (FBS) and 1 % penicillin/streptomycin solution at 37 ˚C in a humidified atmosphere of 5 % CO2 and 95 % air. Cell invasion and migration were determined using Transwell and wound healing assays, respectively. Realtime  quantitative polymerase chain reaction (qRT-PCR) and Western blotting were used for the determination of changes in the levels of expression of Snail, E-cadherin, vimentin, and microRNA-195-5p (miR-195-5p). In vivo tumor growth inhibition was determined 45 days after establishment of GC xenografts in nude mice.Results: Treatment of MKN28 and NCI-N87 cells with tocotrienolic amide significantly and dosedependently reduced their invasiveness and migratory capacity (p < 0.05). It also significantly and dosedependently downregulated the mRNA and protein expressions of Snail and vimentin, but significantly upregulated E-cadherin expression (p < 0.05). The mRNA expression of miR-195-5p was significantly and dose-dependently upregulated in MKN28 and NCI-N87 cells treated with tocotrienolic amide, but was downregulated after transfection with miR-195-5p inhibitor (p < 0.05). Transfection of MKN28 and NCI-N87 cells with miR-195-5p inhibitor significantly and dose-dependently upregulated mRNA and protein expressions of Snail (p < 0.05). Moreover, treatment of GC mice with TCTA led to significant and dose-dependent reduction in tumor weight and volume (p < 0.05).Conclusion: These results suggest that tocotrienolic amide inhibits the growth and metastasis of GC cells by directly targeting Snail and vimentin genes, and thus can potentially be developed for the management of gastric cancer. Keywords: Gastric cancer, Metastasis, Protein expression, Tocotrienolic amide, Tumor volume