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Engineering PD-1-targeted small protein variants for in vitro diagnostics and in vivo PET imaging.
- Source :
-
Journal of translational medicine [J Transl Med] 2024 May 06; Vol. 22 (1), pp. 426. Date of Electronic Publication: 2024 May 06. - Publication Year :
- 2024
-
Abstract
- Background: Programmed cell death 1 (PD-1) belongs to immune checkpoint proteins ensuring negative regulation of the immune response. In non-small cell lung cancer (NSCLC), the sensitivity to treatment with anti-PD-1 therapeutics, and its efficacy, mostly correlated with the increase of tumor infiltrating PD-1 <superscript>+</superscript> lymphocytes. Due to solid tumor heterogeneity of PD-1 <superscript>+</superscript> populations, novel low molecular weight anti-PD-1 high-affinity diagnostic probes can increase the reliability of expression profiling of PD-1 <superscript>+</superscript> tumor infiltrating lymphocytes (TILs) in tumor tissue biopsies and in vivo mapping efficiency using immune-PET imaging.<br />Methods: We designed a 13 kDa β-sheet Myomedin scaffold combinatorial library by randomization of 12 mutable residues, and in combination with ribosome display, we identified anti-PD-1 Myomedin variants (MBA ligands) that specifically bound to human and murine PD-1-transfected HEK293T cells and human SUP-T1 cells spontaneously overexpressing cell surface PD-1.<br />Results: Binding affinity to cell-surface expressed human and murine PD-1 on transfected HEK293T cells was measured by fluorescence with LigandTracer and resulted in the selection of most promising variants MBA066 (hPD-1 KD = 6.9 nM; mPD-1 KD = 40.5 nM), MBA197 (hPD-1 KD = 29.7 nM; mPD-1 KD = 21.4 nM) and MBA414 (hPD-1 KD = 8.6 nM; mPD-1 KD = 2.4 nM). The potential of MBA proteins for imaging of PD-1 <superscript>+</superscript> populations in vivo was demonstrated using deferoxamine-conjugated MBA labeled with <superscript>68</superscript> Galium isotope. Radiochemical purity of <superscript>68</superscript> Ga-MBA proteins reached values 94.7-99.3% and in vitro stability in human serum after 120 min was in the range 94.6-98.2%. The distribution of <superscript>68</superscript> Ga-MBA proteins in mice was monitored using whole-body positron emission tomography combined with computerized tomography (PET/CT) imaging up to 90 min post-injection and post mortem examined in 12 mouse organs. The specificity of MBA proteins was proven by co-staining frozen sections of human tonsils and NSCLC tissue biopsies with anti-PD-1 antibody, and demonstrated their potential for mapping PD-1 <superscript>+</superscript> populations in solid tumors.<br />Conclusions: Using directed evolution, we developed a unique set of small binding proteins that can improve PD-1 diagnostics in vitro as well as in vivo using PET/CT imaging.<br /> (© 2024. The Author(s).)
- Subjects :
- Humans
Animals
HEK293 Cells
Mice
Carcinoma, Non-Small-Cell Lung diagnostic imaging
Carcinoma, Non-Small-Cell Lung pathology
Carcinoma, Non-Small-Cell Lung metabolism
Cell Line, Tumor
Lung Neoplasms diagnostic imaging
Lung Neoplasms pathology
Lung Neoplasms metabolism
Lung Neoplasms genetics
Amino Acid Sequence
Programmed Cell Death 1 Receptor metabolism
Positron-Emission Tomography methods
Protein Engineering
Subjects
Details
- Language :
- English
- ISSN :
- 1479-5876
- Volume :
- 22
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Journal of translational medicine
- Publication Type :
- Academic Journal
- Accession number :
- 38711085
- Full Text :
- https://doi.org/10.1186/s12967-024-05210-x