Development of an orally-administrable tumor vasculature-targeting therapeutic using annexin A1-binding D-peptides.

Motohiro Nonaka,Chun-Teng Huang,Itsuko Kimura-Takagi,Chizuko Nishizawa-Harada,Yoichi Suwa,Michiko N Fukuda,Masato Nagaoka,Hideaki Mabashi-Asazuma,Kazuhiko Yamasaki,Donald L Jarvis,Toshio Sasai,Takashi Yaegashi,Tomoya O Akama,Yu-Hsuan Tsai

doi:10.1371/journal.pone.0241157

Abstract

We previously reported that IF7 peptide, which binds to the annexin A1 (ANXA1) N-terminus, functions as a tumor vasculature-targeted drug delivery vehicle after intravenous injection. To enhance IF7 stability in vivo, we undertook mirror-image peptide phage display using a synthetic D-peptide representing the ANXA1 N-terminus as target. We then identified peptide sequences, synthesized them as D-amino acids, and designated the resulting peptide dTIT7, which we showed bound to the ANXA1 N-terminus. Whole body imaging of mouse brain tumor models injected with near infrared fluorescent IRDye-conjugated dTIT7 showed fluorescent signals in brain and kidney. Furthermore, orally-administered dTIT7/geldanamycin (GA) conjugates suppressed brain tumor growth. Ours is a proof-of-concept experiment showing that ANXA1-binding D-peptide can be developed as an orally-administrable tumor vasculature-targeted therapeutic.

Highlights

It is widely accepted that surfaces of the vasculature are heterogenous and express varying tissue-specific receptors under different pathological conditions [1]
D-MC16 and L-MC16 peptides, which consist of Nterminal residues of human Annexin A1 (ANXA1) plus a cysteine residue at position (MAMVSEFLKQAWFIEC), and L-MC16 mutants were synthesized by Bio-Synthesis (Lewisville, TX)
Since dTIT7 interaction with the MC16 sequence within the ANXA1 N-terminal domain likely occurs when MC16 is localized to the cell membrane, we mimicked this state by coating plastic plates with MC16 peptide and adding a solution of biotinylated dTIT7 to plates

Summary

Introduction

It is widely accepted that surfaces of the vasculature are heterogenous and express varying tissue-specific receptors under different pathological conditions [1]. Oh et al used subtractive proteomics analysis of malignant vs normal vasculature to identify Annexin A1 (ANXA1) as highly specific surface marker of malignant tumor vasculature [2, 3]. Independent of these studies, we looked for carbohydrate mimetic peptides to inhibit cell surface carbohydratedependent hematogenous cancer colonization of the lung [4,5,6]. Since carbohydrate antigen specificity is determined by 3–4 carbohydrate residues of 600–800 Da, we assumed that a 7-mer peptide of 770 Da would mimick a carbohydrate antigen.

Methods

Results

Conclusion