Expression of Sp1/Sp3 may represent a good predictor for selecting HCECs that are most likely to proliferate, stratify, and differentiate properly when used for the production of reconstructed corneal substitutes.

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Unlike FN, which functions as an activator of alpha5 gene transcription, LM repressed transcription, directed by the alpha6 gene promoter, by altering the nuclear levels of Sp1 and Sp3. Reappearance of LM in the basement membrane after repair of the corneal damage is therefore expected to substantially contribute to the final steps of this process by influencing the degree to which genes that encode protein products requested for cell adhesion and migration, such as integrin genes, are expressed during corneal wound healing.

Cancer aggressiveness is related to the ability of cancer cells to escape the anchorage dependency toward the extracellular matrix, a process regulated by the integrin α5β1 and its ligand fibronectin. Here, we characterized the expression of the α5 gene in human uveal melanoma cell lines with distinct tumorigenic properties and investigated some of the mechanisms underlying the variations of their malignancy. Strong and weak expression of α5 was observed in cells with no (T108/T115) and high (T97/T98) tumorigenic properties, respectively. Expression and DNA binding of the transcription factors Sp1, activator protein 1 (AP-1) (both acting as activators), and nuclear factor I (NFI) (a strong repressor) to the α5 promoter were demonstrated in all cell lines. A reduced expression of AP-1 combined with a dramatic increase in NFI correlated with the suppression of α5 expression in T97 and T98 cells. Restoring α5 expression in T97 cells entirely abolished their tumorigenicity in immunodeficient mice. These uveal melanoma cell lines might therefore prove particularly useful as cellular models to investigate α5β1 function in the pathogenesis of invasive uveal melanoma.

Electromobility shift assay is a simple, efficient, and rapid method for the study of specific DNA-protein interactions. It relies on the reduction in the electrophoretic mobility conferred to a DNA fragment by an interacting protein. The technique is suitable to qualitative, quantitative, and kinetic analyses. It can also be used to analyze conformational changes.