Role of promyelocytic leukemia zinc finger protein in proliferation of cultured human corneal endothelial cells

Purpose: To review the role of promyelocytic leukemia zinc finger (PLZF), a transcriptional repressor and negative regulator of cell cycling, in the proliferation of cultured human corneal endothelial cells (HCECs). Methods: The expression pattern of PLZF mRNA was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time quantitative PCR in HCECs and normal human corneal epithelia. The effect of cell-cell contact on expression of the PLZF gene was studied after incubation of the cultured HCECs in EDTA. The proliferation rate of cultured HCECs was assayed by a real-time electronic sensing (RT-CES) system, and DNA microarray analysis was performed to find the PLZF-regulating genes in cultured HCECs infected with LacZ-and PLZF-carrying adenoviruses (Ad-LacZ, Ad-PLZF). Results: PLZF mRNA was expressed in HCECs in vivo and in completely confluent HCECs but not in subconfluent HCECs in vitro. Real-time PCR showed that the expression of PLZF mRNA was decreased by similar to 20-fold when incubated with EDTA and returned to a normal level as the cell-cell contact reformed. Cell proliferation assay by the RT-CES system showed that infection of cultured HCECs with Ad-PLZF inhibited proliferation. Conclusions: These findings suggest that PLZF plays an important role in the suppression of proliferation of HCECs.