High expression of the eukaryotic initiation factors eIF4a and eIF4e in retinoblastoma.

Abstract

Introduction: Retinoblastoma is a malignant, intraocular tumor which deve-lops within the first three years of life and has a variable prognosis. Aberrant expression of eukaryotic initiation factors (eIFs) has been reported in a variety of tumor entities, but there is a lack of data regarding eIF expression in retinoblastoma.

Material and methods: We analyzed the expression of eIF4a and eIF4e in 30 retinoblastomas and samples of other ocular diseases via immunohisto-chemistry. Via western blot, we determined the expression of eIF4a and eIF4e in the two retinoblastoma cell lines WERI-Rb1 and Y79. Furthermore, we evaluated the influence of the eIF inhibitor 4EGI-1 on the cell viabi-lity of both cancer cell lines.

Results: In this study, we observed increased expression of eIF4a and eIF4e in retinoblastoma samples compared to other ocular diseases. We also found that both proteins are expressed in the retinoblastoma cell lines WERI-Rb1 and Y79 and that their expression is independent of treatment with the eIF inhibitor 4EGI-1. However, inhibition of eIF function via 4EGI-1 reduced the cell viability of both cell lines in a dose- and time-dependent manner.

Conclusion: We provide evidence that eIF4a and eIF4e are overexpressed in retinoblastoma and that their inhibition might represent a therapeutic target for the therapy of retinoblastoma.