TGF-β induced apoptosis and reduction of Bcl-2 in human lens epithelial cells in vitro

Abstract

Purpose. TGF-ß has been shown to induce lens epithelial cells to undergo an aberrant growth and transdifferentiation that mimic some characteristics of anterior subcapsular cataract, and posterior capsular opacification. Here we sought to examine whether TGF-ß induces apoptotic cell death in human lens epithelial cells in vitro. Methods. Cell death of human lens epithelial cells HLE-B3 cell line was measured by TUNEL assay, FACS analysis, and DNA fragmentation assay. The expression of Bcl-2 and Bax was examined using reverse transcription-polymerase chain reaction and Western blot analysis. The expression of poly (ADP-ribose) polymerase (PARP) and caspase-3 was examined using Western blot analysis. Results. TGF-ß-induced cell death was detected in human lens epithelial cells by TUNEL assay. DNA fragmentation assay showed the characteristic laddering pattern from the genomic DNA from human lens epithelial cells treated with TGF-ß. The expression of Bcl-2 mRNA and its protein was markedly decreased in human lens epithelial cells treated with TGF-ß. Caspase-3 and PARP were not activated in this process. Conclusions. This study suggests that TGF-ß induces apoptotic cell death in human lens epithelial cells and that decreased expression of Bcl-2 might play a role in this process.