Exogenous expression of p16INK4a is associated with decrease in telomerase activity

In this study, gene transfection was used to determine whether the exogenous expression of p16(INK4a) modulated the biological characteristics of glioblastoma cells. The human glioblastoma cell line U87MG was doubly transfected with the plasmids pVgRXR and pIND harboring the wild-type p16 gene. The expression of p16(INK4a) in the resulting transfectants was regulated by the addition of the ecdysone homologue, muristerone A. When the cells expressed p16(INK4a), their growth capacity was reduced and morphological changes such as an increase in cell size and cellular flattening were observed. The analysis of cell cycle regulation provided evidence that cells expressing p16(INK4a) were inhibited from entry into the cell cycle, as assessed by Ki-67 antigen expression. Tn addition, it was observed that the exogenous expression of p16(INK4a) was associated with decrease in telomerase activity.