Role of insulin-like growth factor binding protein-3 in human umbilical vein endothelial cell senescence.

Whereas insulin-like growth factor binding protein-3 (IGFBP-3) is frequently upregulated in senescent replicatively exhausted human umbilical vein endothelial cells (HUVEC), a systematic analysis of four different HUVEC donors revealed that IGFBP-3 is not consistently upregulated in all isolates at senescence. Lentiviral overexpression of IGFBP-3 inhibited cell proliferation, induced apoptosis and senescence in young HUVEC. Knockdown of IGFBP-3 in senescent HUVEC by lentivirally expressed shRNA did not revert but rather enforced senescence-associated beta-galactosidase staining and apoptosis. Together the data suggest that, although IGFBP-3 acts as an anti-proliferative and premature senescence-inducing protein, the role of IGFBP-3 on senescence depends on the genetic background of the donor, and additional factors might be important to maintain the senescent phenotype.