[Effect of Skp2 antisense oligodeoxynucleotide on growth and proliferation of K562 cells].

Background & Objective: The ubiquitin-proteosome pathway is important for selective degradation of short-lived protein in eukaryotic cells. In this pathway Skp2 (S-phase kinase-associated protein 2) plays a critical role in degrading cyclin-dependent kinase inhibitor p27. It is verified that Skp2 is an oncoprotein that promotes cell cycle progression in solid tumor, but its role in leukemia cells remains unclear. This study was designed to investigate the effect of Skp2 antisense oligodeoxynucleotides(ASODN) on the growth and proliferation of leukemic K562 cells and its probable mechanism.

Methods: K562 cells were cocultured with Skp2 ASODN. The growth and proliferation of K562 cells were observed with light microscopy and MTT assay. The cell cycle was analyzed using flow cytometry. The expression levels of mRNA and protein were determined using reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry, respectively.

Results: After treatment with Skp2 ASODN, the growth and proliferation of K562 cells were inhibited and the cell cycle was arrested at G(0)/G(1) phase(Skp2 ASODN group 39.7+/-9.1% vs. control group 31.5+/-7.3%,P< 0.05). Both Skp2 mRNA and its protein levels were down-regulated. Although p27 mRNA level remained unchanged, its protein level was up-regulated.

Conclusion: Skp2 ASODN can inhibit the growth and proliferation of K562 cells, which is mediated by interfering with ubiquitin-proteosome system and regulating of cell cycle progression.