Islet-1 promotes the proliferation and invasion, and inhibits the apoptosis of A375 human melanoma cells.

Abstract

The aim of this study was to examine the effects of the insulin gene enhancer-binding protein, islet-1(ISL1), on the proliferation, invasion and apoptosis of the human melanoma cell line,A375. An ISL1 overexpression lentiviral vector was constructed and transfected into the A375cells. The proliferation of the A375 cells transfected with the ISL1 vector(termed A375/ISL1cells) was examined by MTT assay, flow cytometry and TUNEL assay, and cell invasion was examined by Transwell assay. The expression levels of matrix metalloproteinase(MMP)-2 and MMP-9 were measured by qPCR and western blot analysis; the expression levels of Akt and p-Akt were measured in the cells treated with vascular endothelial growth factor(VEGF) and the PI3K/Akt inhibitor, LY294002, by western blot analysis. The optical density value of the A375/ISL1cells was increased after 12h of culture(P<0.001), as shown by MTT assay. The ratio of apoptotic A375/ISL1 cells was significantly decreased(P<0.001), as shown by flow cytometry and TUNEL assay. In addition, the average penetration rate of the A375/ISL1cells significantly increased(P<0.001), as shown by Transwell assay. The expression levels of MMP-2 andMMP-9 were significantly increased in the A375/ISL1cells, as shown by qPCR and western blot analysis(P<0.001). Moreover, treatment of the A375/ISL1cells with VEGF for 48h increased the expression of Akt andp-Akt compared with the control cells transfected with A375/green fluorescent protein(GFP)(P<0.05;P<0.001,respectively). In addition, in the A375/ISL1cells treated with the LY294002inhibitor for 24and 48h, the level of Akt was also found to increase compared to the control A375/GFP cells(P<0.05). On the whole, the findings of this study indicate that the overexpression of ISL1 promotes the proliferation and invasion, and inhibits the apoptosis of A375 melanoma cells. ISL1 thus plays an important role in A375cell survival, and these effects are possibly mediate via the PI3K/Akt signaling pathway.