… by positron emission tomography (PET) imaging and ex vivo … clinical PD-L1 PET imaging
because it detects even very low … The peptide WL12 was purchased from CPC Scientific (San …
Abstract
Noninvasive imaging of the immune checkpoint protein programmed death ligand 1 (PD-L1; synonyms: CD274, B7–H1) holds great promise to improve patient selection and, thus, response rates for immune checkpoint therapy (ICT) with monoclonal antibodies targeting the PD1/PD-L1 axis. The PD-L1 specific peptide WL12 (cyclo(AcY-(NMe)A-N-P-H-L-Hyp-W-S-W(Me)-(NMe)Nle-(NMe)Nle-O-C)-G-NH2) was functionalized with the Gallium-68 chelator TRAP by means of click chemistry (CuAAC). The resulting conjugate TRAP-WL12 was labeled with Gallium-68 within 16 min, with approximately 90% radiochemical yield and 99% radiochemical purity, affording Ga-68-TRAP-WL12 with molar activities typically exceeding 100 MBq/nmol. This radiotracer was characterized by positron emission tomography (PET) imaging and ex vivo biodistribution in murine xenografts of nontransfected PD-L1 expressing tumor cell lines, MDA-MB-231 (human breast carcinoma), and H2009 (human lung adenocarcinoma). It showed a favorable biodistribution profile with rapid renal clearance and low background (tumor-to-blood ratio = 26.6, 3 h p.i.). Conjugation of the Ga-68-TRAP moiety to WL12 successfully mitigated the nonspecific uptake of this peptide in organs, particularly the liver. This was demonstrated by comparing Ga-68-TRAP-WL12 with the archetypical Ga-68-DOTA-WL12, for which tumor-to-liver ratios of 1.4 and 0.5, respectively, were found. Although immunohistochemistry (IHC) revealed a low PD-L1 expression in MDA-MB-213 and H2009 xenografts that corresponds well to the clinical situation, PET showed high tumor uptakes (6.6 and 7.3% injected activity per gram of tissue (iA/g), respectively) for Ga-68-TRAP-WL12. Thus, this tracer has the potential for routine clinical PD-L1 PET imaging because it detects even very low PD-L1 expression densities with high sensitivity and may open an avenue to replace PD-L1 IHC of biopsies as the standard means to select potential responders for ICT.
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Shurtleff, V.W., Layton, M.E., Parish, C.A., Perkins, J.J., Schreier, J.D., Wang, Y., Adam, G.C., Alvarez, N., Bahmanjah, S., Bahnck-Teets, C.M. and Boyce, C.W. Journal of Medicinal Chemistry 67, no. 5 (2024): 3935-3958.
- Center for Discovery and Innovation, Hackensack Meridian Health. 111 Ideation Way. Nutley, New Jersey 07110, United States.
- Merck & Co., Inc., Rahway, New Jersey 07065, United States.
The enzymatic activity of recombinantly expressed 3CLPro enzymes from different coronaviruses was measured using the following synthetic quenched FRET peptide: CP488-ESATLQSGLRKAK- (CPQ2)-NH2 (CPC Scientific, San Jose, CA.
Goh, Joleen Pei Zhen. Nanyang Technological University (2023)
9 generic fluorogenic substrates (CPC Scientific) (Figure S4) were added to the final concentration of 20 μM. Fluorescence was measured at Excitation/Emission=330/390 nm on BioTek Synergy H1 microplate reader and proteolytic activity was calculated as a change in relative fluorescence units per sec using the slope of the linear range for this signal.
Design-rules for stapled peptides with in vivo activity and their application to Mdm2/X antagonists.
Chandramohan, A., Josien, H., Yuen, T.Y., Duggal, R., Spiegelberg, D., Yan, L., Juang, Y.C.A., Ge, L., Aronica, P.G., Kaan, H.Y.K. and Lim, Y.H. Nature Communications 15, no. 1 (2024): 489.
- Merck & Co., Inc., Kenilworth, NJ 07033, USA.
- Merck & Co., Inc., Boston, MA 02115, USA
- Merck & Co., Inc., West Point, PA 19486, USA
- Genentech, South San Francisco, CA 94080, USA
We thank Evans (Chen) Ge, Mike (Dixin) Xue, and Simon (Junhua) Li at Chinese Peptide Company (CPC) for peptide synthesis support.
Hao, Liangliang, Renee T. Zhao, Nicole L. Welch, Edward Kah Wei Tan, Qian Zhong, Nour Saida Harzallah, Chayanon Ngambenjawong et al. Nature Nanotechnology (2023): 1-10.
All peptides and oligonucleotides were synthesized and HPLC purified by CPC Scientific and Integrated DNA Technologies (IDT), respectively. Peptide–oligonucleotide conjugates were generated by copper-free click chemistry.
Kikuchi, F., Ikeda, Z., Kakegawa, K., Nishikawa, Y., Sasaki, S., Fukuda, K., Takami, K., Banno, Y., Nishikawa, H., Taya, N. and Nakahata, T. Bioorganic & Medicinal Chemistry 93 (2023): 117462.
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
- Pharmaceutical Sciences, Takeda Pharmaceutical Company Ltd., 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
5FAM-Abu-Gly-Asp-Asp-Asp-Lys-Ile-Val-Gly-Gly-Lys(CPQ2)-Lys-Lys-NH2 (purity: 97.2%, CPC Scientific, Inc.) was diluted with an assay buffer to prepare a 5.4 μM substrate solution.
Senotherapeutic peptide treatment reduces biological age and senescence burden in human skin models.
Zonari, A.; Brace, L. E.; Al-Katib, K.; Porto, W. F.; Foyt, D.; Guiang, M.; Cruz, E. A. O.; Marshall, B.; Gentz, M.; Guimaraes, G. R.; Franco, O. L.; Oliveira, C. R.; Boroni, M.; Carvalho, J. L., NPJ Aging 2023, 9 (1), 10.
The top hit peptides selected (Pep 14, 144, 156, 195, and 393) from the screening and the fluorescence labeled peptide (5FAM-PEG2-Pep 14) were purchased from CPC Scientific Inc. (USA), which synthesized the peptide by solid phase (Fmoc) on a Rink amide resin, with >95% purity, in the form of acetate salt.
Synthetic oligonucleotides constitute an important class of therapeutics developed to treat a variety of indications. Two main synthetic approaches exist for the conjugation of a peptide to an oligonucleotide: parallel and linear. The primary benefit of the linear approach is the one-pot solid-phase assembly and compatibility with machine automation. However, in cases where poor compatibility of peptide and oligo chemistries exist or long peptide and oligo fragments are required, preparing both components separately and linking both compounds together may offer the simplest solution.
Solid-phase peptide synthesis (SPPS) approaches require that the side chains of certain amino acids be protected from undesired reactivity during synthesis. The installation and removal of these protection groups results in a lower atom economy in the production process. Removal of the protection groups often requires large volumes of trifluoroacetic acid (TFA) or other strong acids which can result in lower yields and pose a significant risk to the environment.
Schiemer, J., Maxwell, A., Horst, R., Liu, S., Uccello, D.P., Borzilleri, K., Rajamohan, N., Brown, M.F. and Calabrese, M.F. Nature Communications 14, no. 1 (2023): 1189.
- Discovery Sciences, Pfizer Worldwide Research and Development, Groton, CT, USA
After 3 h the resin was washed with binding buffer until no protein was detected, followed by elution with 0.2 mg ml−1 FLAG peptide DYKDDDDK (CPC Scientific Peptide company)
