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01.12.2018 | Research | Ausgabe 1/2018 Open Access

Journal of Experimental & Clinical Cancer Research 1/2018

A synthetic cell-penetrating peptide derived from nuclear localization signal of EPS8 exerts anticancer activity against acute myeloid leukemia

Zeitschrift:
Journal of Experimental & Clinical Cancer Research > Ausgabe 1/2018
Autoren:
Yiran Chen, Xiaoling Xie, Anqin Wu, Lei Wang, Yuxing Hu, Honghao Zhang, Yuhua Li
Wichtige Hinweise

Electronic supplementary material

The online version of this article (https://​doi.​org/​10.​1186/​s13046-018-0682-x) contains supplementary material, which is available to authorized users.
Yiran Chen and Xiaoling Xie are co-first authors.

Abstract

Background

Oncogenic roles of epidermal growth factor receptor pathway substrate no.8 (EPS8) have been widely reported in various tumors, making targeting of EPS8 an appealing prospect. Here, we describe the role of EPS8 in acute myeloid leukemia (AML) and consider the potential of EPS8 as an anti-AML target. Nuclear localization signal (NLS) residues of tumor-associated proteins are crucial for cell cycle progression, and specific inhibitors derived from the NLS have inhibitory effect on cancer cells. The NLS in EPS8 has potential as a specific anti-AML target.

Methods

Gene Expression Omnibus expression profiles of AML patients were used to test associations between EPS8 expression and AML patient outcome. The biological characteristics of AML cells after EPS8 knockdown were analyzed in vitro and in vivo. A specific peptide (CP-EPS8-NLS) derived from the NLS of EPS8 (amino acids 298–310) was synthesized, and the anti-AML effects of CP-EPS8-NLS were analyzed in cancer cells and in xenograft models. Mutated CP-EPS8-NLS and penetratin served as controls.

Results

We observed that elevated EPS8 expression in AML patients is associated with poor outcome. Knockdown of EPS8 significantly suppressed the survival of AML cells in vitro and in vivo. CP-EPS8-NLS interfered with EPS8-associated signaling and consequently exerted anti-AML activity. Importantly, CP-EPS8-NLS displayed anti-AML activity in various AML cell types, with diminished activity in PBMCs. CP-ESP8-NLS suppressed U937 cell proliferation, and injection of CP-EPS8-NLS exerted potent antitumor activity in the xenograft tumor models. A synergistic effect of CP-EPS8-NLS and chemotherapeutic agents was also observed in vitro and in vivo. Mechanistically, treatment of various AML cells with CP-EPS8-NLS downregulated the expression of EPS8 and its downstream pathways.

Conclusions

The function of CP-EPS8-NLS is explained by the presence of a NLS in EPS8, which has been shown to induce nuclear translocation, consequently resulting in EPS8 overexpression. These results indicate that EPS8 is a potential target for AML treatment.
Zusatzmaterial
Additional file 1: Changes in EGF/PDGF signaling pathway targets analyzed with a RT2 profiler™ PCR assay. A Array layout of the RT2 profiler™ PCR assay. B Changes in EGF/PDGF signaling pathway targets in KG1α/sh1 cells compared with those in KG1α/NC cells. (TIFF 6966 kb)
13046_2018_682_MOESM1_ESM.tif
Additional file 2: The ability of EPS8 to influence AML cells survival. A Changes in EPS8 expression levels after treatment with increasing concentrations of the Akt inhibitor (perifosine) (0 to 40 μM) for 12 and 24 h analyzed by western blot. B Proliferation ability of KG1α cells after EPS8 knockdown. C Colony formation analysis in parental U937 cells or KG1α cells compared with shRNA1- and NC shRNA-infected cells. D Changes in EPS8 associated signaling pathways after EPS8 knockdown analyzed by western blot. (TIFF 7639 kb)
13046_2018_682_MOESM2_ESM.tif
Additional file 3: U937 cells treated with CP-EPS8-NLS for 8 h and observed under a laser confocal scanning microscope. (TIFF 7912 kb)
13046_2018_682_MOESM3_ESM.tif
Additional file 4: Percentage of apoptotic KG1α cells after CP-EPS8-NLS treatment for 24 and 48 h. (TIFF 4126 kb)
13046_2018_682_MOESM4_ESM.tif
Literatur
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