Native Cltx (Cltx-CONH2) was synthesized at CPC Scientific (Sunnyvale, CA) by routine methods and stored dry at -20 °C.
Abstract
Background
Chlorotoxin (Cltx) isolated from scorpion venom is an established tumor targeting and antiangiogenic peptide. Radiolabeled Cltx therapeutic (131I-TM601) yielded promising results in human glioma clinical studies, and the imaging agent tozuleristide, is under investigation in CNS cancer studies. Several binding targets have previously been proposed for Cltx but none effectively explain its pleiotropic effects; its true target remains ambiguous and is the focus of this study.
Methods
A peptide-drug conjugate (ER-472) composed of Cltx linked to cryptophycin as warhead was developed as a tool to probe the molecular target and mechanism of action of Cltx, using multiple xenograft models.
Results
Neuropilin-1 (NRP1), an endocytic receptor on tumor and endothelial cells, was identified as a novel Cltx target, and NRP1 binding by Cltx increased drug uptake into tumor. Metabolism of Cltx to peptide bearing free C-terminal arginine, a prerequisite for NRP1 binding, took place in the tumor microenvironment, while native scorpion Cltx with amidated C-terminal arginine did not bind NRP1, and instead acts as a cryptic peptide. Antitumor activity of ER-472 in xenografts correlated to tumor NRP1 expression. Potency was significantly reduced by treatment with NRP1 blocking antibodies or knockout in tumor cells, confirming a role for NRP1-binding in ER-472 activity. Higher cryptophycin metabolite levels were measured in NRP1-expressing tumors, evidence of NRP1-mediated enhanced drug uptake and presumably responsible for the superior antitumor efficacy.
Conclusions
NRP1 was identified as a novel Cltx target which enhances tumor drug uptake. This finding should facilitate tumor selection for chlorotoxin-based therapeutics and diagnostics.
SOCIAL MEDIA
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Solid-phase peptide synthesis (SPPS) has many advantages over liquid-phase peptide synthesis (LPPS) for preparing and manufacturing synthetic peptides. Except the synthesis of short peptide sequences (i.e., less than five amino acid residues), SPPS is faster, more efficient, and more economical than liquid-phase peptide synthesis (LPPS). Some of the advantages of SPPS include: (1) Excess reagents and products can be easily washed away, (2) using excess reagents to increase reaction rates and drive reactions to completion, (3) intermediates do not require isolation or characterization, (4) access to a broader range of solvents with low volatility and high polarity, (5) tethered peptide provides a ‘pseudo-dilute’ microenvironment, which can inhibit intermolecular reactions, making some modifications easier to accomplish, and (6) compatibility with automated synthesis technology.
Lo, J.H., Hao, L., Muzumdar, M.D., Raghavan, S., Kwon, E.J., Pulver, E.M., Hsu, F., Aguirre, A.J., Wolpin, B.M., Fuchs, C.S. and Hahn, W.C. Molecular Cancer Therapeutics 17, no. 11 (2018): 2377-2388.
pTP-TAMRA-iRGD (CH3(CH)15-[GWTLNSAGYLLGKINLKALAALAKKIL-GGK(TAMRA)GGCRGDKGPDC, Cys-Cys bridge]) used in all figures except Fig. S1 was synthesized by CPC Scientific.
Ng, Ee Xien, Myat Noe Hsu, Guoyun Sun, and Chia-Hung Chen. Methods in Enzymology 628 (2019): 59-94.
The peptide sequences of the four FRET-based substrates ([..] CPC Scientific) are as follows: UV: AlexaFluor405-Leu-Ala-Gln-Ala-HompheArg-Ser-Lys (QSY35)-NH2; Blue: Dabcyl-Gly-Pro-Leu-Gly-Met-Arg-Gly-Lys (5-FAM)-NH2; Green: QSY7-Ala-Pro-Phe-Glu..
West, J.A., Tsakmaki, A., Huang, J.H., Ghosh, S.S., Parkes, D.G., Wismann, P., Rigbolt, K.T., Pedersen, P.J., Pavlidis, P., Maggs, D. and Lopez-Talavera, J.C. bioRxiv (2019) 822122.
- Fractyl Laboratories Inc, Lexington, MA, 02421, USA
- Diabetes Research Group, School of Life Course Sciences, Faculty of Life Science and Medicine, King’s College London, London, WC2R 2LS, England, UK
[..] infusion of vehicle 2 via osmotic minipump; (2) glucagon-like peptide-1 receptor (GLP-1R) agonist (0.2 mg/kg liraglutide, SC, QD, Victoza (Novo Nordisk, Bagsværd, Denmark) and continuous infusion of vehicle 2 via osmotic minipump; (3) vehicle 1 (SC, QD) and continuous infusion of a glucose-dependent insulinotropic polypeptide receptor (GIPR) antagonist (∼4.5 mg/kg/day / 56.8 nmol/kg/h GIP[3-30]NH2, CPC Scientific Inc, Sunnyvale, CA, USA) via osmotic minipump;
Artur Javmen, Vladimir Y. Toshchakov, et al. Journal of Leukocyte Biology (2019).
All CPDPs included the N‐terminal Antennapedia homeodomain sequence RQIKIWFQNRRMKWKK.38 The Cy3‐labeled peptides were produced by CPC Scientific (Sunnyvale, CA, USA). The Cy3 label was placed at the peptide N‐terminus..
Gilles, Maud-Emmanuelle, Slack, Frank J, et al. Oncotarget, 2019, Vol. 10, (No. 51), pp: 5349-5358
"Tandem peptide (pTP-iRGD: CH3(CH)15-GWTLNSAGYLLGKINLKALAALAKKIL-GGK(TAMRA)GGCRGDKGPDC, Cys-Cys bridge) was synthesized by CPC Scientific."
Garner, Thomas P., Dulguun Amgalan, Denis E. Reyna, Sheng Li, Richard N. Kitsis, and Evripidis Gavathiotis. Nature Chemical Biology 15, no. 4 (2019): 322.
"Hydrocarbon-stapled peptides corresponding to the BH3 domain of BIM, BIM SAHBA2: N-acetylated- and FITC-Ahx-EIWIAQELRS5IGDS5FNAYYA-CONH2, where S5 represents the non-natural amino acid inserted for olefin metathesis, were synthesized, purified at >95% purity by CPC Scientific Inc. and characterized as previously described."
Gibbs, Ebrima, Judith M. Silverman, Beibei Zhao, Xubiao Peng, Jing Wang, Cheryl L. Wellington, Ian R. Mackenzie, Steven S. Plotkin, Johanne M. Kaplan, and Neil R. Cashman. Scientific Reports 9, no. 1 (2019): 1-14.
The conformational epitope was synthesized as a cyclic peptide with additional N-terminal residues CG and a C-terminal G to recapitulate the predicted structure of HHQK on AβO. Peptide synthesis was performed by CPC Scientific Inc. (Sunnyvale CA, USA) [..] Cyclization was performed via a head-to-tail (C-G) amide bond and c[CGHHQKG] was then conjugated to either keyhole limpet hemocyanin (KLH) or bovine serum albumin (BSA) via maleimide-based coupling.
SUNNYVALE, US. and Hangzhou, China, June 24th, 2019 /CPCNewswire/ — CPC Scientific Inc. and its affiliate Chinese Peptide Company, a public Hangzhou-based CDMO (Stock Symbol: 002390) is pleased to announce today that their GMP manufacturing facility, has successfully passed its inspection by the competent authority of Germany as an“active substance manufacturer that has been inspected […]