S phase kinase-interacting protein 2 targeting SiRNA inhibits cell proliferation of tenon's capsule fibroblast by increasing p27 protein level.

Invest Ophthalmol Vis Sci 51(3):1475-82 (2010) PMID 19875654

Objective: Although antiproliferative drugs have been used to prevent scarring after filtration surgery in patients with glaucoma, there are complications associated with their use. In the present study, we investigated wheather small interfering RNA (siRNA)-mediated gene silencing of Skp2 can be employed to increase p27 kip1 level and inhibit cell proliferation in rabbit Tenon's capsule fibroblast (rTF). Methods: A plasmid containing Skp2 siRNA was used to decrease the high constitutive level of Skp2 protein in rTF which can lead to consequent degradation of p27 kip1. Cell proliferation was assayed by immunocytochemistry using antibodies against 59-bromodeoxyuridine (BrdU) and proliferating cell neuclear antigen (PCNA). Skp2 siRNA was delivered to trabeculectomy animal model to study the effect on rTF proliferation in vivo. Results: Immunocytochemistry and Western blot showed a decreased level of Skp2 and increased level of p27 kip1 in cells transfected with pSkp2 siRNA, but not in vehicle transfection and uninfected cells in vitro and in vivo. MTT assay showed that cell viability significantly declined in rTF transfected with Skp2 siRNA. Skp2 siRNA transfected cells showed significantly less Brdu and PCNA positive staining compared with control cells in vitro and in vivo. Infitration bleb was detected in Skp2 siRNA group 14 days after trabeculectomy. Conclusions: Skp2 siRNA inhibited cell proliferation and decreased cell viability of rTF in vivo and in vitro. Our findings suggest that siRNA-mediated gene silencing of Skp2 can be a novel gene therapy to treat scarring after glaucoma surgery by suppression of p27 kip1 down-regulation.