Kyung-Ho Jung, Jin Hee Lee, Mina Kim, Y. Cho, Kyung-Han Lee
{"title":"89Zr Immuno-PET Imaging of Tumor PD-1 Reveals That PMA Upregulates Lymphoma PD-1 through NFκB and JNK Signaling","authors":"Kyung-Ho Jung, Jin Hee Lee, Mina Kim, Y. Cho, Kyung-Han Lee","doi":"10.1155/2022/5916692","DOIUrl":null,"url":null,"abstract":"Immune therapy of T-cell lymphoma requires assessment of tumor-expressed programmed cell death protein-1 (PD-1). Herein, we developed an immuno-PET technique that quantitatively images and monitors regulation of PD-1 expression on T-cell lymphomas. Methods. Anti-PD-1 IgG underwent sulfhydryl moiety-specific conjugation with maleimide-deferoxamine and 89Zr labeling. Binding assays and Western blotting were performed in EL4 murine T-cell lymphoma cells. In vivo pharmacokinetics, biodistribution, and PET were performed in mice. Results. 89Zr-PD-1 IgG binding to EL4 cells was completely blocked by cold antibodies, confirming excellent target specificity. Following intravenous injection into mice, 89Zr-PD-1 IgG showed biexponential blood clearance and relatively low normal organ uptake after five days. PET/CT and biodistribution demonstrated high EL4 tumor uptake that was suppressed by cold antibodies. In EL4 cells, phorbol 12-myristate 13-acetate (PMA) increased 89Zr-PD-1 IgG binding (305.5 ± 30.6%) and dose-dependent augmentation of PD-1 expression (15.8 ± 3.8 − fold of controls by 200 ng/ml). FACS showed strong PD-1 expression on all EL4 cells and positive but weaker expression on 41.6 ± 2.1% of the mouse spleen lymphocytes. PMA stimulation led to 2.7 ± 0.3-fold increase in the proportion of the strongest PD-1 expressing EL4 cells but failed to influence that of PD-1+ mouse lymphocytes. In mice, PMA treatment increased 89Zr-PD-1 IgG uptake in EL4 lymphomas from 6.6 ± 1.6 to 13.9 ± 3.6%ID/g (P = 0.01), and tumor uptake closely correlated with PD-1 level (r = 0.771, P < 0.001). On immunohistochemistry of tumor sections, infiltrating CD8α+ T lymphocytes constituted a small fraction of tumor cells. The entire tumor section showed strong PD-1 staining that was even stronger for PMA-treated mice. Investigation of involved signaling revealed that PMA increased EL4 cell and tumor HIF-1α accumulation and NFκB and JNK activation. Conclusion. 89Zr-PD-1 IgG offered high-contrast PET imaging of tumor PD-1 in mice. This was found to mostly represent binding to EL4 tumor cells, although infiltrating T lymphocytes may also have contributed. PD-1 expression on T-cell lymphomas was upregulated by PMA stimulation, and this was reliably monitored by 89Zr-PD-1 IgG PET. This technique may thus be useful for understanding the mechanisms of PD-1 regulation in lymphomas of living subjects.","PeriodicalId":49796,"journal":{"name":"Molecular Imaging","volume":null,"pages":null},"PeriodicalIF":2.8000,"publicationDate":"2022-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Molecular Imaging","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1155/2022/5916692","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Medicine","Score":null,"Total":0}
引用次数: 2
Abstract
Immune therapy of T-cell lymphoma requires assessment of tumor-expressed programmed cell death protein-1 (PD-1). Herein, we developed an immuno-PET technique that quantitatively images and monitors regulation of PD-1 expression on T-cell lymphomas. Methods. Anti-PD-1 IgG underwent sulfhydryl moiety-specific conjugation with maleimide-deferoxamine and 89Zr labeling. Binding assays and Western blotting were performed in EL4 murine T-cell lymphoma cells. In vivo pharmacokinetics, biodistribution, and PET were performed in mice. Results. 89Zr-PD-1 IgG binding to EL4 cells was completely blocked by cold antibodies, confirming excellent target specificity. Following intravenous injection into mice, 89Zr-PD-1 IgG showed biexponential blood clearance and relatively low normal organ uptake after five days. PET/CT and biodistribution demonstrated high EL4 tumor uptake that was suppressed by cold antibodies. In EL4 cells, phorbol 12-myristate 13-acetate (PMA) increased 89Zr-PD-1 IgG binding (305.5 ± 30.6%) and dose-dependent augmentation of PD-1 expression (15.8 ± 3.8 − fold of controls by 200 ng/ml). FACS showed strong PD-1 expression on all EL4 cells and positive but weaker expression on 41.6 ± 2.1% of the mouse spleen lymphocytes. PMA stimulation led to 2.7 ± 0.3-fold increase in the proportion of the strongest PD-1 expressing EL4 cells but failed to influence that of PD-1+ mouse lymphocytes. In mice, PMA treatment increased 89Zr-PD-1 IgG uptake in EL4 lymphomas from 6.6 ± 1.6 to 13.9 ± 3.6%ID/g (P = 0.01), and tumor uptake closely correlated with PD-1 level (r = 0.771, P < 0.001). On immunohistochemistry of tumor sections, infiltrating CD8α+ T lymphocytes constituted a small fraction of tumor cells. The entire tumor section showed strong PD-1 staining that was even stronger for PMA-treated mice. Investigation of involved signaling revealed that PMA increased EL4 cell and tumor HIF-1α accumulation and NFκB and JNK activation. Conclusion. 89Zr-PD-1 IgG offered high-contrast PET imaging of tumor PD-1 in mice. This was found to mostly represent binding to EL4 tumor cells, although infiltrating T lymphocytes may also have contributed. PD-1 expression on T-cell lymphomas was upregulated by PMA stimulation, and this was reliably monitored by 89Zr-PD-1 IgG PET. This technique may thus be useful for understanding the mechanisms of PD-1 regulation in lymphomas of living subjects.
期刊介绍:
Molecular Imaging is a peer-reviewed, open access journal highlighting the breadth of molecular imaging research from basic science to preclinical studies to human applications. This serves both the scientific and clinical communities by disseminating novel results and concepts relevant to the biological study of normal and disease processes in both basic and translational studies ranging from mice to humans.