A human-derived reporter gene for noninvasive imaging in humans: Mitochondrial thymidine kinase type 2 Journal Article
| Authors: | Ponomarev, V.; Doubrovin, M.; Shavrin, A.; Serganova, I.; Beresten, T.; Ageyeva, L.; Cai, C.; Balatoni, J.; Alauddin, M.; Gelovani, J. |
| Article Title: | A human-derived reporter gene for noninvasive imaging in humans: Mitochondrial thymidine kinase type 2 |
| Abstract: | A human-derived intrinsically nonimmunogenic reporter gene was tested for PET imaging of different molecular-genetic processes for potential clinical use. Methods: The human mitochondrial thymidine kinase type 2 (hTK2) reporter gene truncated at the N terminus (ΔhTK2), alone or fused with green fluorescent protein (GFP), was used for preclinical evaluation in a mouse model. The levels of enzymatic activity of ΔhTK2 and ΔhTK2 GFP proteins were assessed using radiotracer accumulation and prodrug activation assays in vitro and in subcutaneous tumors grown from the corresponding cell lines in nude mice. Kinetic analyses of 124I-2′-fluoro-2′-deoxy-1-β-D- β-arabinofuranosyl-5-iodouracil (FIAU), 18F-2′-fluoro- 2′-deoxy-1-β-D-β-arabinofuranosyl-5-ethyluracil (FEAU), or 18F-9-(4-18F-fluoro-3-hydroxymethylbutyl)guanine (FHBG) uptake in tumors and biodistribution studieswere performed. Results: ΔhTK2 was successfully expressed in the cytoplasm of transduced cells. A new anti-hTK2 monoclonal antibody 8G2 was developed. The levels of FIAU and FEAU accumulation in cells expressing ΔhTK2 and ΔhTK2 GFP were at least 10-fold higher than in wild-type cells in vitro and about 6 times higher in vivo. We determined that FEAU is a more specific reporter substrate for ΔhTK2 than FIAU, whereas FHBG is not phosphorylated by this enzyme. In addition, we showed that ΔhTK2 transduced cells can be eliminated by treatment with D-arabinofuranosyl-cytosine. Conclusion: We have tested a human-derived reporter gene that is likely to be non-immunogenic and potentially allows for long-term monitoring of different molecular-genetic processes by nuclear imaging techniques in humans. Using 124I-FIAU, 18F-FIAU, or 18F-FEAU, it should be possible to image ΔhTK2 reporter gene expression with PET in preclinical and clinical studies. Copyright © 2007 by the Society of Nuclear Medicine, Inc. |
| Keywords: | controlled study; protein expression; unclassified drug; genetics; nonhuman; positron emission tomography; glioma; mouse; metabolism; green fluorescent protein; animal experiment; animal model; tumor xenograft; enzymology; enzyme activity; enzyme substrate; molecular imaging; cell line, tumor; monoclonal antibody; enzyme phosphorylation; amino terminal sequence; diagnostic agent; drug distribution; tumor cell line; radioactivity; 2' fluoro 2' deoxy 1 beta dextro beta arabinofuranosyl 5 ethyluracil f 18; radiopharmaceutical agent; scintiscanning; reporter gene; thymidine kinase; genes, reporter; pet; mitochondria; non invasive procedure; mitochondrion; feau; fiau; penciclovir; human mitochondrial thymidine kinase; 2' fluoro 2' deoxy 1 beta dextro beta arabinofuranosyl 5 iodouracil i 124; 9 (4 fluoro 3 hydroxymethylbutyl f 18)guanine f 18; cytosine derivative; dextro arabinofuranosyl cytosine; monoclonal antibody 8g2; thymidine kinase 2 |
| Journal Title: | Journal of Nuclear Medicine |
| Volume: | 48 |
| Issue: | 5 |
| ISSN: | 0161-5505 |
| Publisher: | Society of Nuclear Medicine |
| Date Published: | 2007-05-01 |
| Start Page: | 819 |
| End Page: | 826 |
| Language: | English |
| DOI: | 10.2967/jnumed.106.036962 |
| PUBMED: | 17468435 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 29" - "Export Date: 17 November 2011" - "CODEN: JNMEA" - "Source: Scopus" |
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