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Autophagy Induction by Endothelial-Monocyte Activating Polypeptide II Contributes to the Inhibition of Malignant Biological Behaviors by the Combination of EMAP II with Rapamycin in Human Glioblastoma.

Ma J, Meng F, Li S, Liu L, Zhao L, Liu Y, Hu Y, Li Z, Yao Y, Xi Z, Teng H, Xue Y - Front Mol Neurosci (2015)

Bottom Line: In this study, EMAP II inhibited the cell viability and decreased the mitochondrial membrane potential in human GBM cells and GSCs, and autophagy inhibitor 3-methyl adenine (3-MA) blocked these effects.In addition, the up-regulation of microtubule-associated protein-1 light chain-3 (LC3)-II and the down-regulation of autophagic degraded substrate p62/SQSTM1 caused by EMAP II were observed.The combination of EMAP II with rapamycin demonstrated the inhibitory effect on the malignant biological behaviors of human GBM cells and GSCs in vitro and in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, College of Basic Medicine, China Medical University Shenyang, China ; Institute of Pathology and Pathophysiology, China Medical University Shenyang, China.

ABSTRACT
This study aims to investigate the effect of endothelial-monocyte activating polypeptide II (EMAP II) on human glioblastoma (GBM) cells and glioblastoma stem cells (GSCs) as well as its possible mechanisms. In this study, EMAP II inhibited the cell viability and decreased the mitochondrial membrane potential in human GBM cells and GSCs, and autophagy inhibitor 3-methyl adenine (3-MA) blocked these effects. Autophagic vacuoles were formed in these cells after EMAP II treatment and this phenomenon was blocked by 3-MA. In addition, the up-regulation of microtubule-associated protein-1 light chain-3 (LC3)-II and the down-regulation of autophagic degraded substrate p62/SQSTM1 caused by EMAP II were observed. Cells treated with EMAP-II inhibited the PI3K/Akt/mTOR signal pathway, and PI3K/Akt agonist insulin-like growth factor-1 (IGF-1) blocked the effect of EMAP II on the expression of LC3-II and p62/SQSTM1. Cells exposed to EMAP-II experienced mitophagy and ER stress. Furthermore, the inhibition of cell proliferation, migration and invasion of GBM cells and GSCs were more remarkable by the combination of EMAP II and rapamycin than either agent alone in vitro and in vivo. The current study demonstrated that the cytotoxicity of EMAP II in human GBM cells and GSCs was induced by autophagy, accompanied by the inhibition of PI3K/Akt/mTOR signal pathway, mitophagy and ER stress. The combination of EMAP II with rapamycin demonstrated the inhibitory effect on the malignant biological behaviors of human GBM cells and GSCs in vitro and in vivo.

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Effects of EMAP II and IGF-1 on the expression of LC3 and p62/SQSTM1 in human GBM cells and GSCs. (A) Western blot analysis of the expression levels of LC3-II/LC3-I and p62/SQSTM1 in U87, U118, and GSCs after treatment with EMAP II, IGF-1 and their combination. IDV of LC3-II/LC3-I and p62/SQSTM1 are shown. Values represented the means ± SD (n = 5, each). ∗∗P < 0.01 vs. control group, ##P < 0.01 vs. EMAP II group. (B) The distribution and expression of LC3 and p62/SQSTM1 in U87, U118, and GSCs. Scale bar = 20 μm.
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Figure 5: Effects of EMAP II and IGF-1 on the expression of LC3 and p62/SQSTM1 in human GBM cells and GSCs. (A) Western blot analysis of the expression levels of LC3-II/LC3-I and p62/SQSTM1 in U87, U118, and GSCs after treatment with EMAP II, IGF-1 and their combination. IDV of LC3-II/LC3-I and p62/SQSTM1 are shown. Values represented the means ± SD (n = 5, each). ∗∗P < 0.01 vs. control group, ##P < 0.01 vs. EMAP II group. (B) The distribution and expression of LC3 and p62/SQSTM1 in U87, U118, and GSCs. Scale bar = 20 μm.

Mentions: As shown in Figure 4A, the expression of p-PI3K/PI3K and p-PI3K/GAPDH were decreased in U87, U118, and GSCs at 0.5, 1, and 2 h after 0.05 nM EMAP II treatment compared with the control group (P < 0.01), and the lowest points were at 0.5 h. The expression of p-Akt/Akt, p-Akt/GAPDH, p-mTOR/mTOR, and p-mTOR/GAPDH exhibited similar results as above (Figures 4B,C). As shown in Figure 5A, compared with the control group, cells treated with 0.05 nM EMAP II at 0.5 h significantly up-regulated the LC3-II expression and down-regulated the p62/SQSTM1 expression in U87, U118, and GSCs (P < 0.01). In addition, the LC3-II expression in EMAP II+IGF-1 group was decreased, whereas the p62/SQSTM1 expression in this group was increased compared with EMAP II group (P < 0.01). These results suggested that IGF-1 could block the effect of EMAP II on the expression of LC3-II and p62/SQSTM1. Moreover, results from immunofluorescence assay were consistent with the above results (Figure 5B).


Autophagy Induction by Endothelial-Monocyte Activating Polypeptide II Contributes to the Inhibition of Malignant Biological Behaviors by the Combination of EMAP II with Rapamycin in Human Glioblastoma.

Ma J, Meng F, Li S, Liu L, Zhao L, Liu Y, Hu Y, Li Z, Yao Y, Xi Z, Teng H, Xue Y - Front Mol Neurosci (2015)

Effects of EMAP II and IGF-1 on the expression of LC3 and p62/SQSTM1 in human GBM cells and GSCs. (A) Western blot analysis of the expression levels of LC3-II/LC3-I and p62/SQSTM1 in U87, U118, and GSCs after treatment with EMAP II, IGF-1 and their combination. IDV of LC3-II/LC3-I and p62/SQSTM1 are shown. Values represented the means ± SD (n = 5, each). ∗∗P < 0.01 vs. control group, ##P < 0.01 vs. EMAP II group. (B) The distribution and expression of LC3 and p62/SQSTM1 in U87, U118, and GSCs. Scale bar = 20 μm.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4664732&req=5

Figure 5: Effects of EMAP II and IGF-1 on the expression of LC3 and p62/SQSTM1 in human GBM cells and GSCs. (A) Western blot analysis of the expression levels of LC3-II/LC3-I and p62/SQSTM1 in U87, U118, and GSCs after treatment with EMAP II, IGF-1 and their combination. IDV of LC3-II/LC3-I and p62/SQSTM1 are shown. Values represented the means ± SD (n = 5, each). ∗∗P < 0.01 vs. control group, ##P < 0.01 vs. EMAP II group. (B) The distribution and expression of LC3 and p62/SQSTM1 in U87, U118, and GSCs. Scale bar = 20 μm.
Mentions: As shown in Figure 4A, the expression of p-PI3K/PI3K and p-PI3K/GAPDH were decreased in U87, U118, and GSCs at 0.5, 1, and 2 h after 0.05 nM EMAP II treatment compared with the control group (P < 0.01), and the lowest points were at 0.5 h. The expression of p-Akt/Akt, p-Akt/GAPDH, p-mTOR/mTOR, and p-mTOR/GAPDH exhibited similar results as above (Figures 4B,C). As shown in Figure 5A, compared with the control group, cells treated with 0.05 nM EMAP II at 0.5 h significantly up-regulated the LC3-II expression and down-regulated the p62/SQSTM1 expression in U87, U118, and GSCs (P < 0.01). In addition, the LC3-II expression in EMAP II+IGF-1 group was decreased, whereas the p62/SQSTM1 expression in this group was increased compared with EMAP II group (P < 0.01). These results suggested that IGF-1 could block the effect of EMAP II on the expression of LC3-II and p62/SQSTM1. Moreover, results from immunofluorescence assay were consistent with the above results (Figure 5B).

Bottom Line: In this study, EMAP II inhibited the cell viability and decreased the mitochondrial membrane potential in human GBM cells and GSCs, and autophagy inhibitor 3-methyl adenine (3-MA) blocked these effects.In addition, the up-regulation of microtubule-associated protein-1 light chain-3 (LC3)-II and the down-regulation of autophagic degraded substrate p62/SQSTM1 caused by EMAP II were observed.The combination of EMAP II with rapamycin demonstrated the inhibitory effect on the malignant biological behaviors of human GBM cells and GSCs in vitro and in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, College of Basic Medicine, China Medical University Shenyang, China ; Institute of Pathology and Pathophysiology, China Medical University Shenyang, China.

ABSTRACT
This study aims to investigate the effect of endothelial-monocyte activating polypeptide II (EMAP II) on human glioblastoma (GBM) cells and glioblastoma stem cells (GSCs) as well as its possible mechanisms. In this study, EMAP II inhibited the cell viability and decreased the mitochondrial membrane potential in human GBM cells and GSCs, and autophagy inhibitor 3-methyl adenine (3-MA) blocked these effects. Autophagic vacuoles were formed in these cells after EMAP II treatment and this phenomenon was blocked by 3-MA. In addition, the up-regulation of microtubule-associated protein-1 light chain-3 (LC3)-II and the down-regulation of autophagic degraded substrate p62/SQSTM1 caused by EMAP II were observed. Cells treated with EMAP-II inhibited the PI3K/Akt/mTOR signal pathway, and PI3K/Akt agonist insulin-like growth factor-1 (IGF-1) blocked the effect of EMAP II on the expression of LC3-II and p62/SQSTM1. Cells exposed to EMAP-II experienced mitophagy and ER stress. Furthermore, the inhibition of cell proliferation, migration and invasion of GBM cells and GSCs were more remarkable by the combination of EMAP II and rapamycin than either agent alone in vitro and in vivo. The current study demonstrated that the cytotoxicity of EMAP II in human GBM cells and GSCs was induced by autophagy, accompanied by the inhibition of PI3K/Akt/mTOR signal pathway, mitophagy and ER stress. The combination of EMAP II with rapamycin demonstrated the inhibitory effect on the malignant biological behaviors of human GBM cells and GSCs in vitro and in vivo.

No MeSH data available.


Related in: MedlinePlus