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Zheleznyak A, Tang R, Duncan K, Manion B, Liang K, Xu B, Vanover A, Ghai A, Prior J, Lees S, Achilefu S, Kelly K, Shokeen M. Development of New CD38 Targeted Peptides for Cancer Imaging. Mol Imaging Biol 2024:10.1007/s11307-024-01901-5. [PMID: 38480650 DOI: 10.1007/s11307-024-01901-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 04/18/2024]
Abstract
PURPOSE Multiple myeloma (MM) affects over 35,000 patients each year in the US. There remains a need for versatile Positron Emission Tomography (PET) tracers for the detection, accurate staging, and monitoring of treatment response of MM that have optimal specificity and translational attributes. CD38 is uniformly overexpressed in MM and thus represents an ideal target to develop CD38-targeted small molecule PET radiopharmaceuticals to address these challenges. PROCEDURES Using phage display peptide libraries and pioneering algorithms, we identified novel CD38 specific peptides. Imaging bioconjugates were synthesized using solid phase peptide chemistry, and systematically analyzed in vitro and in vivo in relevant MM systems. RESULTS The CD38-targeted bioconjugates were radiolabeled with copper-64 (64Cu) with100% radiochemical purity and an average specific activity of 3.3 - 6.6 MBq/nmol. The analog NODAGA-PEG4-SL022-GGS (SL022: Thr-His-Tyr-Pro-Ile-Val-Ile) had a Kd of 7.55 ± 0.291 nM and was chosen as the lead candidate. 64Cu-NODAGA-PEG4-SL022-GGS demonstrated high binding affinity to CD38 expressing human myeloma MM.1S-CBR-GFP-WT cells, which was blocked by the non-radiolabeled version of the peptide analog and anti-CD38 clinical antibodies, daratumumab and isatuximab, by 58%, 73%, and 78%, respectively. The CD38 positive MM.1S-CBR-GFP-WT cells had > 68% enhanced cellular binding when compared to MM.1S-CBR-GFP-KO cells devoid of CD38. Furthermore, our new CD38-targeted radiopharmaceutical allowed visualization of tumors located in marrow rich bones, remaining there for up to 4 h. Clearance from non-target organs occurred within 60 min. Quantitative PET data from a murine disseminated tumor model showed significantly higher accumulation in the bones of tumor-bearing animals compared to tumor-naïve animals (SUVmax 2.06 ± 0.4 versus 1.24 ± 0.4, P = 0.02). Independently, tumor uptake of the target compound was significantly higher (P = 0.003) compared to the scrambled peptide, 64Cu-NODAGA-PEG4-SL041-GGS (SL041: Thr-Tyr-His-Ile-Pro-Ile-Val). The subcutaneous MM model demonstrated significantly higher accumulation in tumors compared to muscle at 1 and 4 h after tracer administration (SUVmax 0.8 ± 0.2 and 0.14 ± 0.04, P = 0.04 at 1 h; SUVmax 0.89 ± 0.01 and 0.09 ± 0.01, P = 0.0002 at 4 h). CONCLUSIONS The novel CD38-targeted, radiolabeled bioconjugates were specific and allowed visualization of MM, providing a starting point for the clinical translation of such tracers for the detection of MM.
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Affiliation(s)
- Alexander Zheleznyak
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Rui Tang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Kathleen Duncan
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Brad Manion
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Kexian Liang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Baogang Xu
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Alexander Vanover
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Anchal Ghai
- Department of Biomedical Engineering, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Julie Prior
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Stephen Lees
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, 22908, USA
| | - Samuel Achilefu
- Department of Biomedical Engineering, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Kimberly Kelly
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, 22908, USA
| | - Monica Shokeen
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Alvin J. Siteman Cancer Center, Washington University School of Medicine and Barnes-Jewish Hospital, St. Louis, MO, 63110, USA.
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63110, USA.
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA.
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