Acta Pharmacologica Sinica 2006 December; 27 (12): 1630-1636; doi: 10.1111/j.1745-7254.2006.00459.x

Aim: Overexpression of midkine (MK) has been observed in many malignancies. This aim of this study is to screen for suitable antisense oligonucleotides (ASODN) targeting MK in hepatocellular carcinoma (HCC) cells and evaluate its antitumor activity.

Methods: Ten ASODN targeting MK were designed and synthesized. After transfection with ASODN, cell proliferation was analyzed with MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium, inner salt] assay. In addition, MK mRNA, protein levels, as well as apoptosis and caspase-3 activity were also examined in HepG2 cells. Cell proliferation was then analyzed after treatment with both ASODN and chemotherapeutic drugs.

Results: In this experiment, the ASODN5 among the 10 ASODN showed higher inhibitory activity against proliferation of hepatocellular carcinoma cells in a dose-dependent manner. In HepG2 cells, ASODN5 could significantly reduce the MK mRNA level and protein content. After transfection with ASODN5 for 48 h, accompanied with a decline of survivin and Bcl-2 protein content, a remarkable increase of apoptosis and caspase-3 activity was observed in HepG2 cells. Furthermore, ASODN5 transfer can significantly increase chemosensitivity in HepG2 cells.

Conclusion: Antisense oligonucleotidestargeting MK shows therapeutic effectson HCC; ASODN5 has the possibility to be developed as an effective antitumor agent.

Keywords: antisense oligonucleotide; midkine; apopto-sis; hepatocellular carcinoma; chemosen-sitivity