ERα increases expression and interacts with TERT in cataractous canine lens epithelial cells

PURPOSE: Estrogen receptor alpha (ERα) expression has previously been evaluated in lens epithelial cells (LEC). However, its function in the lens has not been determined. One potential function may be its interaction with the catalytic subunit of telomerase (TERT), which is present in normal LEC and higher in LEC that have undergone epithelial to mesenchymal transition (EMT). ERα is known to play a role in EMT, a process that may also involve TERT. METHODS: A commercially available transcription factor array was used to evaluate potential interactions between TERT and other proteins in normal and cataractous LEC. Based on these findings, ERα protein and mRNA expressions were measured using western blot analysis, immunohistochemical staining, and quantitative reverse transcription polymerase chain reaction (RT–PCR). Co-immunoprecipitation assays were used to evaluate the interaction of TERT with ERα as well as their phosphorylation in normal and cataractous LEC. RESULTS: The transcription factor array suggested that TERT interacted with ERα via the estrogen response element (ERE) in cataractous LEC but not in normal LEC. Expression of ERα protein and mRNA increased in cataractous LEC compared with normal LEC. Co-immunoprecipitation assays confirmed the interaction of TERT with ERα in cataractous LEC while no interaction was found in normal LEC. LEC that have undergone EMT, e.g., cataracts, are rapidly proliferating and migrating along the posterior lens capsule. CONCLUSIONS: ERα is known to play a role in EMT, and our data suggests that TERT and phosphorylated protein kinase B (pAkt) may be involved in the regulation of this process in cataractous LEC.