Expression of angiotensin Ⅱ in A375 human malignant melanoma cells and its influence on angiogenesis / 中华皮肤科杂志

ABSTRACT

Objective To investigate the expression of angiotensin Ⅱ (Ang Ⅱ) in malignant melanoma cells and to explore the influence of Ang Ⅱ on angiogenesis. Methods The expression of Ang Ⅱ in the supernatant of A375 cells and primary human melanocytes was detected by radioimmunoassay.Human umbilical vein endothelial cells (HUVECs) were incubated with Ang Ⅱ of 1 μmol/L for 20 hours in an in vitro tube formation assay to observe the effects of Ang Ⅱ on tube formation.A375 cells were incubated with angiotensin Ⅱ of 1 μmol/L and losartan (an inhibitor of angiotensin Ⅱ type 1 receptor,AT1R) of 1 μmol/L,respectively for 24 hours; subsequently, reverse transcription PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA)were carried out to measure the mRNA and protein expressions of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF),respectively.Results The level of Ang Ⅱ was 37.29 ± 0.27 pmol/L in the supernatant of A375 cells,significantly higher than that in the supernatant of normal human melanocytes (21.58 ± 0.32 pmol/L,P ＜ 0.05).Ang Ⅱ apparently promoted the tube formation by HUVECs.Intact tubiform structures were formed by HUVECs in two-dimension matrigel after being treated with Ang Ⅱ of 1 μmol/L,with the area of tubiform structures being 2.5 ± 0.3 times that in the HUVECs treated with phosphate buffered solution (PBS) (P ＜ 0.05).The protein expressions of VEGF and bFGF in the supernatant of A375 cells and their mRNA expressions in A375 cells were significantly increased by Ang Ⅱ,but suppressed by losartan (all P ＜ 0.05).Conclusions There is a local overexpression of Ang Ⅱ in malignant melanoma,which can markedly promote angiogenesis.This may be one of the mechanisms by which the local renin-angiotensin system affects the initiation of malignant melanoma.