Effects of vascular endothelial growth factor and insulin growth factor-1 on proliferation, migration, osteogenesis and vascularization of human carious dental pulp stem cells

Abstract

The present study aimed to investigate the effects of vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) on the proliferation, migration and differentiation of human carious dental pulp stem cells (hCD PSCs), and to elucidate the underlying mechanism(s). Cell counting kit-8 assay was used to detect the effect of different concentrations of IGF-1 and VEGF on the proliferation of hCD PSCs. Transwell assay was used to detect the migratory ability of the hCD PSCs. Alizarin red and alkaline phosphatase (AL P) staining were used to detect the osteogenic ability of hCD PSCs, whereas the angiogenic ability of the hCD PSCs was tested by tube formation assay. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to detect the expression levels of associated genes and proteins. IGF-1 (100 ng/ml) or VEGF (25 ng/ml) alone were revealed to be able to promote proliferation and migration of hCD PSCs; however, the combined use of IGF-1 and VEGF enhanced this effect when compared with the use of either agent in isolation. Alizarin red and AL P staining revealed that the use of either VEGF or IGF-1 alone did not result in any significant effects, whereas their use in combination promoted the osteogenic differentiation of hCD PSCs. In addition, the RT-qPCR and western blotting analyses revealed that the expression levels of Runt-related transcription factor 2 (RUN X2), bone sialoprotein (BSP) and AL P were increased upon combined treatment of the cells with VEGF and IGF-1. The expression levels of VEGF and plateletderived growth factor (PDGF) in hCD PSCs were enhanced upon treatment with either VEGF or IGF-1 in isolation, with greater effects observed when VEGF and IGF-1 were added in combination, indicating that VEGF and IGF-1 may exert a synergisticrole in these events. Further experiments revealed that the combination of VEGF and IGF-1 led to an activation of the AKT signaling pathway. The proliferation and angiogenesis of hCD PSCs were also shown to be more effective compared with treatment with either VEGF or IGF-1 in isolation. Taken together, the present study has demonstrated that the combined use of VEGF and IGF-1 leads to an increase in the proliferation, migration, osteogenesis and angiogenesis of hCD PSCs and, furthermore, these signaling molecules may mediate their effects via activation of the AKT signaling pathway.