Motif mimetic of epsin perturbs tumor growth and metastasis
Yunzhou Dong, … , R. Sathish Srinivasan, Hong Chen
Yunzhou Dong, … , R. Sathish Srinivasan, Hong Chen
Published November 16, 2015
Citation Information: J Clin Invest. 2015;125(12):4349-4364. https://doi.org/10.1172/JCI80349.
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Research Article Angiogenesis Cardiology Oncology Vascular biology

Motif mimetic of epsin perturbs tumor growth and metastasis

Abstract

Tumor angiogenesis is critical for cancer progression. In multiple murine models, endothelium-specific epsin deficiency abrogates tumor progression by shifting the balance of VEGFR2 signaling toward uncontrolled tumor angiogenesis, resulting in dysfunctional tumor vasculature. Here, we designed a tumor endothelium–targeting chimeric peptide (UPI) for the purpose of inhibiting endogenous tumor endothelial epsins by competitively binding activated VEGFR2. We determined that the UPI peptide specifically targets tumor endothelial VEGFR2 through an unconventional binding mechanism that is driven by unique residues present only in the epsin ubiquitin–interacting motif (UIM) and the VEGFR2 kinase domain. In murine models of neoangiogenesis, UPI peptide increased VEGF-driven angiogenesis and neovascularization but spared quiescent vascular beds. Further, in tumor-bearing mice, UPI peptide markedly impaired functional tumor angiogenesis, tumor growth, and metastasis, resulting in a notable increase in survival. Coadministration of UPI peptide with cytotoxic chemotherapeutics further sustained tumor inhibition. Equipped with localized tumor endothelium–specific targeting, our UPI peptide provides potential for an effective and alternative cancer therapy.

Authors

Yunzhou Dong, Hao Wu, H.N. Ashiqur Rahman, Yanjun Liu, Satish Pasula, Kandice L. Tessneer, Xiaofeng Cai, Xiaolei Liu, Baojun Chang, John McManus, Scott Hahn, Jiali Dong, Megan L. Brophy, Lili Yu, Kai Song, Robert Silasi-Mansat, Debra Saunders, Charity Njoku, Hoogeun Song, Padmaja Mehta-D’Souza, Rheal Towner, Florea Lupu, Rodger P. McEver, Lijun Xia, Derek Boerboom, R. Sathish Srinivasan, Hong Chen

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Figure 1

UPI mimetic targets endothelial cells and tumor vasculature to block epsin-VEGFR2 interaction.

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UPI mimetic targets endothelial cells and tumor vasculature to block eps...
(A) Alignment of the UPI mimetic peptide with UIMs of human epsins (hEpsin), murine epsins (mEpsin), and yeast Vps27 (yVps). (B) Schematic of the UPI peptide depicting the UIM (pink), plasma membrane–anchoring (PM anchor) sequence (green), and iRGD-homing sequence (yellow). (C) Ribbon diagrams of yeast Vps27 UIM (left), epsin UIM (middle), and UPI (right) peptides predicted using PEP-FOLD. (D) Ribbon diagrams of yeast Vps27 UIM-ubiquitin (Ub) complex (left), human epsin UIM-Ub complex (middle), and UPI-Ub complex (right). (E) Ribbon diagram showing UPI peptide (red) docked into the VEGFR2 KD (blue). (F) FACS analysis of surface αvβ3 expression in HUVECs transfected with HUVECαvβ3. HUVECs transfected with pcDNA3 were used as a control (see also Supplemental Figure 1A). P < 0.001, by 2-tailed Student’s t test. (G) FUPI selectivity in HUVECs and HUVECαvβ3 treated with 10 μM FUPI for 15 hours. Representative image (n = 5). Scale bar: 100 μm. (H) Pharmacokinetic analysis of FUPI peptide stability in tumor vasculature of s.c. B16 tumor–bearing mice injected i.v. once with FUPI peptide (10 mg/kg). Tumors were harvested at the indicated time points and processed for immunofluorescence staining with anti-CD31 Ab. Data represent the average percentage of FUPI peptide–positive vessels relative to total CD31-positive vessels (n = 5). See also Supplemental Figure 1E. (I) Tissue distribution of FUPI peptide in s.c. LLC tumor–bearing mice 4 hours after i.v. injection (10 mg/kg FUPI). FITC fluorescence intensity was analyzed by confocal microscopy and quantified (n = 4). *P < 0.001, by 1-way ANOVA. See also Supplemental Figure 2A. (J) Representative Western blot showing UPI peptide inhibition of epsin 1 IP by VEGFR2 KD (His) analyzed by coincubating control or UPI peptide and anti-His Ab in lysates from 293T cells overexpressing HA-tagged epsin 1 and His-tagged VEGFR2 KD (n = 5). CTR, control; pep-1, peptide 1; pep-2, peptide 2.