Abstract
Purpose: :
Maspin (mammary serine protease inhibitor), a member of the serine protease inhibitor superfamily, was identified as a tumor suppressor that inhibits cell motility, invasion, angiogenesis, and metastasis. The purpose of our study was to investigate maspin expression in normal retinal pigment epithelial cells (RPE) and retinal tissues and the regulation of maspin by the DNA methylation inhibitor 5-aza-2’-deoxycytidine (5-AZA).
Methods: :
The expression of maspin was evaluated by immunohistochemistry in early passage cultured human RPE cells, fetal retinal tissue sections, normal adult retinal tissue sections and human surgically excised proliferative vitreoretinopathy (PVR) membranes. Maspin mRNA expression was analyzed by RT-PCR. The regulation of maspin expression by 5-AZA was evaluated using Western blot at different time points (2 uM ,6 h,16 h,24 h,48 h,72 h) and different doses (5-AZA, 0.1,1,2,6 uM) for 72 hours.
Results: :
Immunohistochemistry, Western blot and RT-PCR showed positive maspin expression in cultured human RPE cells, and in normal fetal and adult retinal sections. Maspin expression in cultured RPE was significantly enhanced by 5-AZA treatment (24h, 48h, 72h, 6 uM, p<0.05). In human PVR membranes, weak staining for maspin was identified but the intensity of staining was reduced, when compared to normal tissues.
Keywords: retinal pigment epithelium