Abstract
Purpose :
Crystallin proteins are major constituents of the vertebrate eye lens and are divided into two primary classes, α-crystallins and β, γ-crystallins. αB-crystallin (CRYAB) is a small heat shock protein and molecular chaperone. The heat shock response of CRYAB has been studied in triple negative breast cancer, but not in ocular melanoma. We provide the first expression patterning of CRYAB and other crystallin proteins in ocular melanoma to show the presence of the heat shock response and its implications in ocular melanoma development and migration in the eye.
Methods :
OCM3 malignant melanoma cells derived from human eye tissue were grown to 80% confluence. Protein lysates were prepared and centrifuged to remove cellular debris. A BCA protein assay was performed on the lysates and SDS-PAGE gel electrophoresis separated the proteins. Western blotting was performed for CRYAB, αA-crystallin (CRYAA), β-crystallin, and γ-crystallin and the results were analyzed using ImageJ software with retinal pigmented epithelial (RPE) cells as a control.
Results :
Each protein analyzed had an immunoreactive band on the western blot within the expected size range. As expected, CRYAB protein expression was present in both RPE cells and OCM3 cells, with a slight upregulation observed in OCM3 cells. CRYAA was not detected in RPE cells, but appeared to be present as a weak band in OCM3 cells. β and γ-crystallin both had slight expressions in RPE cells and were upregulated in ocular melanoma.
Conclusions :
The findings shed light into the role of crystallin proteins in ocular melanoma. CRYAB expression from western blot analysis shows that there is active molecular chaperone activity in ocular melanoma. In addition, other crystallins appear to be present in low abundance in ocular melanoma and may have roles in its development and cellular progression. These findings raise questions about how exactly crystallins, particularly CRYAB, may contribute to ocular melanoma’s migratory ability.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.