OBJECTIVESTo study the inhibitory effect of specially synthesized oligodeoxynucleotide (SODN) on malignant phenotype of human hepatocellular carcinoma Hep3B cells by complementary binding to the fourth promoter of IGF-2 gene.

METHODSA SODN was synthesized according to the sequence of the fourth promoter of IGF-2 gene, and was then transfected into Hep3B cells which overexpressed IGF-2. IGF-2 gene transcription activity and protein expression were assayed by RT-PCR and Western blot methods. The effect on cell growth by SODN was estimated by MTT method, and the effect on cell cycle distribution was measured by flow cytometry. Colony formation assay was performed on 6-well tissue culture dishes. Alteration on mobility and invasiveness were studied used transwell plates.

RESULTSIGF-2 mRNA and protein levels in Hep3B cells transfected with SODN were significantly lower in comparison with those in control groups (Hep3B cells and Hep3B cells transfected with a control oligodeoxynucleotide). Results also showed that SODN did not have inhibitory effects on cell growth and mobility of Hep3B cells, but did have an effect on its colony formation and invasiveness.

CONCLUSIONSODN has inhibitory effect on IGF-2 expression in Hep3B cells as a molecular switch, which partially alterates the malignant phenotype of this cell line.