Differentiation of Y79 retinoblastoma cells induced by succinylated concanavalin A

The growth and differentiation potential of Y79 human retinoblastoma cells was assessed in vitro following treatment with the differentiating agent succinylated concanavalin A (SCA). Since SCA treatment induced Y79 cells to display differentiated morphologies in vitro, we sought to determine potential differentiated phenotypes with the use of retinal cell markers. Seventy-two h after SCA treatment, Y79 cells exhibited a decrease in the glial cell marker GFAP and a dramatic and reversible increase in the photoreceptor marker IRBP, while maintaining neuron-specific enolase and PGP 9.5 positivity. These results were indicative of a predominantly neuronal, photoreceptor cell population in response to SCA treatment. In addition, Y79 cell growth inhibition was observed in response to SCA, which could be reversed within 24 h of treatment with the blocking sugar α-methyl-D- mannoside. These changes were accompanied by a significant modulation of the N-MYC oncoprotein, as detected by Western blot analysis and immunocytochemistry. Thus, in this system, the status of N-MYC seems to be closely linked to changes in the growth and differentiated state of SCA- treated Y79 retinoblastoma cells.