Small interfering RNA targeting of S phase kinase-interacting protein 2 inhibits cell proliferation of pterygium fibroblasts

PURPOSE: Fibroblast cell proliferation is major reason for recurrence of pterygia. In the present study, we investigated if small interfering RNA (siRNA)-mediated gene silencing of S phase-kinase-interacting protein 2 (Skp2) can be employed to inhibit protein 27 kinase inhibition protein 1 (p27(kip1)) down-regulation in pterygium fibroblast cells (PFC) in vitro and in vivo. METHODS: A plasmid containing transgenes encoding Skp2 siRNA was used to decreasing the high constitutive levels of Skp2 protein in PFC and normal fibrboblast cells (NFC) in vitro and in vivo which can lead to consequent degradation of p27(kip1). Cell proliferation and viability were investigated using cell counts, 59-bromodeoxyuridine incorporation (BrdU assay) and tetrazolium reduction (MTT assay). RESULTS: Infection of PFC and NFC with Skp2 siRNA resulted in significant inhibition of cell proliferation and metabolic activity in vitro. Immunoflurescence showed decreased levels of Skp2 and increased levels of p27(kip1) in pSkp2 siRNA infected cells, but not in plasmid and uninfected cells. CONCLUSIONS: Skp2 siRNA inhibited the cell proliferation of PFC in vitro and in vivo.