Antisense oligodeoxynucleotides targeting the serine/threonine kinase Pim-2 inhibited proliferation of DU-145 cells

Aim: To investigate the effect of antisense oligodeoxynucleotides (ASODN) targeting Pim-2 on cell proliferation of DU-145 cells. Methods: Three ASODN targeting Pim-2 were designed and synthesized. After transfection with ASODN, cell proliferation was analyzed using an MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assay. In addition, Pim-2 mRNA, protein levels, and cell cycles were examined. Results: The ASODN designed and synthesized by our laboratory significantly reduced Pim-2 mRNA level and protein content in DU-145 cells. After transfection with ASODN for 48 h, a marked reduction in cell viability was observed in DU-145 cells in a dose-dependent manner. No remarkable apoptosis occurred in cells treated with ASODN compared with control cells. However, it should be noted that G ₁ phase arrest was clearly observed in ASODN-treated cells. Conclusion: ASODN targeting Pim-2 resulted in a marked reduction in DU-145 cell proliferation, and induction of G₁ phase cell cycle arrest is one of the important mechanisms for ASODN to reduce cell growth. Moreover, antisense inhibition of Pim-2 expression provides a new promising therapy target for prostate cancer.