Name: pretargeted radioimmunotherapy based on the inverse electron demand diels-alder reaction
Uploaded: 2019-01-29T14:30:00
Description: Watch this Scientific Journal Video about Pretargeted Radioimmunotherapy Based on the Inverse Electron Demand Diels-Alder Reaction at JoVE.com

The authors thank Dr. Jacob Houghton for helpful conversations.&#160;The authors would also like to thank the NIH for their generous funding (R00CA178205 and U01CA221046).

All in vivo animal experiments described in this work were performed according to approved protocols and executed under the ethical guidelines of the Memorial Sloan Kettering Cancer Center, Weill Cornell Medical Center, and Hunter College Institutional Animal Care and Use Committees (IACUC).
1. The preparation of huA33-TCO
NOTE: The synthesis of huA33-TCO has been previously reported29. However, for the ease of the reader, it is replic...

<ol>
	<li>Goldenberg, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+Therapy+of+Cancer+with+Radiolabeled+Antibodies.">Targeted Therapy of Cancer with Radiolabeled Antibodies.</a> Journal of Nuclear Medicine. 43 (5), 693-713 (2002).</li><li>Goldenberg, D. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radioimmunotherapy+of+B-cell+Lymphomas+with+Iodine-131-labeled+LL2+Monoclonal+Antibody.">Radioimmunotherapy of B-cell Lymphomas with Iodine-131-labeled LL2 Monoclonal Antibody.</a> Journal of Clinical Oncology. 9 (4), 548-564 (1991).</li><li>Kaminski, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radioimmunotherapy+with+131I-Tositumomab+for+Relapsed+or+Refractory+B-cell+non-Hodgkin+Lymphoma:+Updated+Results+and+Long-Term+Follow-Up+of+the+University+of+Michigan+Experience.">Radioimmunotherapy with 131I-Tositumomab for Relapsed or Refractory B-cell non-Hodgkin Lymphoma: Updated Results and Long-Term Follow-Up of the University of Michigan Experience.</a> Blood. 96 (4), 1259-1266 (2000).</li><li>Davies, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radioimmunotherapy+for+B-cell+Lymphoma:+Y90+Ibritumomab+Tiuxetan+and+I131+Tositumomab.">Radioimmunotherapy for B-cell Lymphoma: Y90 Ibritumomab Tiuxetan and I131 Tositumomab.</a> Oncogene. 26, 3614 (2007).</li><li>Rajendran, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+Radiation+Dose+Estimation+for+Myeloablative+Radioimmunotherapy+for+Relapsed+or+Recurrent+Mantle+Cell+Lymphoma+Using+131I+Tositumomab+to+That+of+Other+Types+of+Non-Hodgkin's+Lymphoma.">Comparison of Radiation Dose Estimation for Myeloablative Radioimmunotherapy for Relapsed or Recurrent Mantle Cell Lymphoma Using 131I Tositumomab to That of Other Types of Non-Hodgkin's Lymphoma.</a> Cancer Biotherapy and Radiopharmaceuticals. 19 (6), 738-745 (2004).</li><li>Rajendran, J. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Dose+131I-Tositumomab+(Anti-CD20)+Radioimmunotherapy+for+Non-Hodgkin's+Lymphoma:+Adjusting+Radiation+Absorbed+Dose+to+Actual+Organ+Volumes.">High-Dose 131I-Tositumomab (Anti-CD20) Radioimmunotherapy for Non-Hodgkin's Lymphoma: Adjusting Radiation Absorbed Dose to Actual Organ Volumes.</a> Journal of Nuclear Medicine. 45 (6), 1059-1064 (2004).</li><li>Larson, S. M., Carrasquillo, J. A., Cheung, N. -. K. V., Press, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radioimmunotherapy+of+Human+tumours.">Radioimmunotherapy of Human tumours.</a> Nature Reviews Cancer. 15 (6), 347-360 (2015).</li><li>Kelly, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+Targeting+by+a+Multivalent+Single-Chain+Fv+(scFv)+Anti-Lewis+Y+Antibody+Construct.">Tumor Targeting by a Multivalent Single-Chain Fv (scFv) Anti-Lewis Y Antibody Construct.</a> Cancer Biotherapy &#38; Radiopharmaceuticals. 23 (4), 411-423 (2008).</li><li>Yazaki, P. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+Targeting+of+Radiometal+Labeled+Anti-CEA+Recombinant+T84.66+Diabody+and+T84.66+Minibody:+Comparison+to+Radioiodinated+Fragments.">Tumor Targeting of Radiometal Labeled Anti-CEA Recombinant T84.66 Diabody and T84.66 Minibody: Comparison to Radioiodinated Fragments.</a> Bioconjugate Chemistry. 12 (2), 220-228 (2001).</li><li>van Duijnhoven, S. M. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diabody+Pretargeting+with+Click+Chemistry+In+Vivo.">Diabody Pretargeting with Click Chemistry In Vivo.</a> Journal of Nuclear Medicine. 56 (9), 1422-1428 (2015).</li><li>Altai, M., Membreno, R., Cook, B., Tolmachev, V., Zeglis, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pretargeted+Imaging+and+Therapy.">Pretargeted Imaging and Therapy.</a> Journal of Nuclear Medicine. 58 (10), 1553-1559 (2017).</li><li>Goldenberg, D. M., Chatal, J. -. F., Barbet, J., Boerman, O., Sharkey, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cancer+Imaging+and+Therapy+with+Bispecific+Antibody+Pretargeting.">Cancer Imaging and Therapy with Bispecific Antibody Pretargeting.</a> Update on cancer therapeutics. 2 (1), 19-31 (2007).</li><li>Rossin, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-Vivo+Chemistry+for+Pretargeted+Tumor+Imaging+in+Live+Mice.">In-Vivo Chemistry for Pretargeted Tumor Imaging in Live Mice.</a> Angewandte Chemie International Edition. 49 (19), 3375-3378 (2010).</li><li>Gestin, J. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-Step+Targeting+of+Xenografted+Colon+Carcinoma+Using+a+Bispecific+Antibody+and+188Re-Labeled+Bivalent+Hapten:+Biodistribution+and+Dosimetry+Studies.">Two-Step Targeting of Xenografted Colon Carcinoma Using a Bispecific Antibody and 188Re-Labeled Bivalent Hapten: Biodistribution and Dosimetry Studies.</a> Journal of Nuclear Medicine. 42 (1), 146-153 (2001).</li><li>Green, D. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+Analysis+of+Bispecific+Antibody+and+Streptavidin-Targeted+Radioimmunotherapy+for+B-cell+Cancers.">Comparative Analysis of Bispecific Antibody and Streptavidin-Targeted Radioimmunotherapy for B-cell Cancers.</a> Cancer Research. 76 (22), 6669 (2016).</li><li>Sharkey, R. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+Streptavidin&#8722;Anti-Carcinoembryonic+Antigen+Antibody,+Radiolabeled+Biotin+Pretargeting+Method+for+Radioimmunotherapy+of+Colorectal+Cancer.+Studies+in+a+Human+Colon+Cancer+Xenograft+Model.">Development of a Streptavidin&#8722;Anti-Carcinoembryonic Antigen Antibody, Radiolabeled Biotin Pretargeting Method for Radioimmunotherapy of Colorectal Cancer. Studies in a Human Colon Cancer Xenograft Model.</a> Bioconjugate Chemistry. 8 (4), 595-604 (1997).</li><li>Knox, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+II+Trial+of+Yttrium-90-DOTA-Biotin+Pretargeted+by+NR-LU-10+Antibody/Streptavidin+in+Patients+with+Metastatic+Colon+Cancer.">Phase II Trial of Yttrium-90-DOTA-Biotin Pretargeted by NR-LU-10 Antibody/Streptavidin in Patients with Metastatic Colon Cancer.</a> Clinical Cancer Research. 6 (2), 406 (2000).</li><li>Schubert, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+Tumor+Pretargeting+System+Based+on+Complementary+L-Configured+Oligonucleotides.">Novel Tumor Pretargeting System Based on Complementary L-Configured Oligonucleotides.</a> Bioconjugate Chemistry. 28 (4), 1176-1188 (2017).</li><li>Forero, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+1+Trial+of+a+Novel+Anti-CD20+Fusion+Protein+in+Pretargeted+Radioimmunotherapy+for+B-cell+Non-Hodgkin+Lymphoma.">Phase 1 Trial of a Novel Anti-CD20 Fusion Protein in Pretargeted Radioimmunotherapy for B-cell Non-Hodgkin Lymphoma.</a> Blood. 104 (1), 227 (2004).</li><li>Kalofonos, H. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+of+Tumor+in+Patients+with+Indium-111-Labeled+Biotin+and+Streptavidin-Conjugated+Antibodies:+Preliminary+Communication.">Imaging of Tumor in Patients with Indium-111-Labeled Biotin and Streptavidin-Conjugated Antibodies: Preliminary Communication.</a> Journal of Nuclear Medicine. 31 (11), 1791-1796 (1990).</li><li>Zeglis, B. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Pretargeted+PET+Imaging+Strategy+Based+on+Bioorthogonal+Diels-Alder+Click+Chemistry.">A Pretargeted PET Imaging Strategy Based on Bioorthogonal Diels-Alder Click Chemistry.</a> Journal of Nuclear Medicine. 54 (8), 1389-1396 (2013).</li><li>Meyer, J. -. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=18F-Based+Pretargeted+PET+Imaging+Based+on+Bioorthogonal+Diels-Alder+Click+Chemistry.">18F-Based Pretargeted PET Imaging Based on Bioorthogonal Diels-Alder Click Chemistry.</a> Bioconjugate Chemistry. 27 (2), 298-301 (2016).</li><li>Rossin, R., L&#228;ppchen, T., vanden Bosch, S. M., Laforest, R., Robillard, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diels-Alder+Reaction+for+Tumor+Pretargeting:+In+Vivo+Chemistry+Can+Boost+Tumor+Radiation+Dose+Compared+with+Directly+Labeled+Antibody.">Diels-Alder Reaction for Tumor Pretargeting: In Vivo Chemistry Can Boost Tumor Radiation Dose Compared with Directly Labeled Antibody.</a> Journal of Nuclear Medicine. 54 (11), 1989-1995 (2013).</li><li>Zeglis, B. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+a+Pretargeted+Strategy+for+the+PET+Imaging+of+Colorectal+Carcinoma+via+the+Modulation+of+Radioligand+Pharmacokinetics.">Optimization of a Pretargeted Strategy for the PET Imaging of Colorectal Carcinoma via the Modulation of Radioligand Pharmacokinetics.</a> Molecular Pharmaceutics. 12 (10), 3575-3587 (2015).</li><li>Agard, N. J., Prescher, J. A., Bertozzi, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Strain-Promoted+[3+++2]+Azide&#8722;Alkyne+Cycloaddition+for+Covalent+Modification+of+Biomolecules+in+Living+Systems.">A Strain-Promoted [3 + 2] Azide&#8722;Alkyne Cycloaddition for Covalent Modification of Biomolecules in Living Systems.</a> Journal of the American Chemical Society. 126 (46), 15046-15047 (2004).</li><li>Blackman, M. L., Royzen, M., Fox, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tetrazine+Ligation:+Fast+Bioconjugation+Based+on+Inverse-Electron-Demand+Diels&#8722;Alder+Reactivity.">Tetrazine Ligation: Fast Bioconjugation Based on Inverse-Electron-Demand Diels&#8722;Alder Reactivity.</a> Journal of the American Chemical Society. 130 (41), 13518-13519 (2008).</li><li>Houghton, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishment+of+the+In+Vivo+Efficacy+of+Pretargeted+Radioimmunotherapy+Utilizing+Inverse+Electron+Demand+Diels-Alder+Click+Chemistry.">Establishment of the In Vivo Efficacy of Pretargeted Radioimmunotherapy Utilizing Inverse Electron Demand Diels-Alder Click Chemistry.</a> Molecular Cancer Therapeutics. 16 (1), 124-133 (2017).</li><li>Membreno, R., Cook, B. E., Fung, K., Lewis, J. S., Zeglis, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Click-Mediated+Pretargeted+Radioimmunotherapy+of+Colorectal+Carcinoma.">Click-Mediated Pretargeted Radioimmunotherapy of Colorectal Carcinoma.</a> Molecular Pharmaceutics. 15 (4), 1729-1734 (2018).</li><li>Reiner, T., Lewis, J. S., Zeglis, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Harnessing+the+Bioorthogonal+Inverse+Electron+Demand+Diels-Alder+Cycloaddition+for+Pretargeted+PET+Imaging.">Harnessing the Bioorthogonal Inverse Electron Demand Diels-Alder Cycloaddition for Pretargeted PET Imaging.</a> Journal of Visualized Experiments. (96), e52335 (2015).</li><li>Cook, B. E., Membreno, R., Zeglis, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendrimer+Scaffold+for+the+Amplification+of+In+Vivo+Pretargeting+Ligations.">Dendrimer Scaffold for the Amplification of In Vivo Pretargeting Ligations.</a> Bioconjugate Chemistry. 29 (8), 2734-2740 (2018).</li><li>Cheal, S. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theranostic+Pretargeted+Radioimmunotherapy+of+Colorectal+Cancer+Xenografts+in+Mice+Using+Picomolar+Affinity+Y-86-+or+Lu-177-DOTA-Bn+Binding+scFv+C825/GPA33+IgG+Bispecific+Immunoconjugates.">Theranostic Pretargeted Radioimmunotherapy of Colorectal Cancer Xenografts in Mice Using Picomolar Affinity Y-86- or Lu-177-DOTA-Bn Binding scFv C825/GPA33 IgG Bispecific Immunoconjugates.</a> European journal of nuclear medicine and molecular imaging. 43 (5), 925-937 (2016).</li><li>Meyer, J. -. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioorthogonal+Masking+of+Circulating+Antibody-TCO+Groups+Using+Tetrazine-Functionalized+Dextran+Polymers.">Bioorthogonal Masking of Circulating Antibody-TCO Groups Using Tetrazine-Functionalized Dextran Polymers.</a> Bioconjugate Chemistry. 29 (2), 538-545 (2018).</li><li>Houghton, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pretargeted+Immuno-PET+of+Pancreatic+Cancer:+Overcoming+Circulating+Antigen+and+Internalized+Antibody+to+Reduce+Radiation+Doses.">Pretargeted Immuno-PET of Pancreatic Cancer: Overcoming Circulating Antigen and Internalized Antibody to Reduce Radiation Doses.</a> Journal of Nuclear Medicine. 57 (3), 453-459 (2016).</li><li>Kein&#228;nen, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pretargeting+of+Internalizing+Trastuzumab+and+Cetuximab+with+a+(18)F-Tetrazine+Tracer+in+Xenograft+Models.">Pretargeting of Internalizing Trastuzumab and Cetuximab with a (18)F-Tetrazine Tracer in Xenograft Models.</a> European Journal of Nuclear Medicine and Molecular Imaging Research. 7, 95 (2017).</li><li>Billaud, E. M. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micro-flow+Photosynthesis+of+New+Dienophiles+for+Inverse-Electron-Demand+Diels-Alder+Reactions.+Potential+Applications+for+Pretargeted+In+Vivo+PET+Imaging.">Micro-flow Photosynthesis of New Dienophiles for Inverse-Electron-Demand Diels-Alder Reactions. Potential Applications for Pretargeted In Vivo PET Imaging.</a> Chemical Science. 8 (2), 1251-1258 (2017).</li></ol>

One of the strengths of this approach to in vivo pretargeting &#8212; especially in relation to strategies predicated on bispecific antibodies and radiolabeled haptens &#8212; is its modularity: trans-cyclooctene moieties can be appended to any antibody, and tetrazine radioligands can be radiolabeled with an extraordinary variety of radionuclides without impairing their ability to react with their click partners. Yet the adaptation of this approach to other antibody/antigen system is not as simple as du...

Radioimmunotherapy (RIT) &#8212; the use of antibodies for the delivery of therapeutic radionuclides to tumors &#8212; has long been an enticing approach to the treatment of cancer1,2. Indeed, this promise has been underscored by the United States Food and Drug Administration&#8217;s approval of two radioimmunoconjugates for the treatment of Non-Hodgkin&#8217;s Lymphoma: 90Y-ibritumomab tiuxetan and 131I-tositumomab3,4. Yet even from its earliest days, the clinical prospects of RIT have been hampered by a critical complication: high radiation dose rates to healthy tissues5,6. Generally speaking, radioimmunoconjugates for RIT are labeled with long-lived radionuclides (e.g., 131I [t&#189; = 8.0 days] and 90Y [t&#189; = 2.7 days]) with physical half-lives that dovetail well with the long pharmacokinetic half-lives of immunoglobulins. This is essential, as it ensures that sufficient radioactivity remains once the antibody has reached its optimal biodistribution after several days of circulation. However, this combination of long residence times in the blood and long physical half-lives inevitably results in the irradiation of healthy tissues, thereby reducing therapeutic ratios and limiting the efficacy of therapy7. Several strategies have been explored to circumvent this problem, including the use of truncated antibody fragments such as Fab, Fab&#39;, F(ab&#39;)2, minibodies, and nanobodies8,9,10. One of the most promising and fascinating, yet undeniably complex, alternative approaches is in vivo pretargeting11.
In vivo pretargeting is an approach to nuclear imaging and therapy that seeks to harness the exquisite affinity and selectivity of antibodies while skirting their pharmacokinetic drawbacks11,12,13. To this end, the radiolabeled antibody used in traditional radioimmunotherapy is deconstructed into two components: a small molecule radioligand and an immunoconjugate that can bind both a tumor antigen and the aforementioned radioligand. The immunoconjugate is injected first and given a &#8216;head start&#8217;, often several days, during which it accumulates in the target tissue and clears from the blood. Subsequently, the small molecule radioligand is administered and either combines with the immunoconjugate at the tumor or rapidly clears from the body. In essence, in vivo pretargeting relies upon performing radiochemistry within the body itself. By reducing the circulation of the radioactivity, this approach simultaneously reduces radiation doses to healthy tissues and facilitates the use of radionuclides (e.g., 68Ga, t&#189; = 68 min211; As, t&#189; = 7.2 h) with half-lives that are typically considered incompatible with antibody-based vectors.
Starting in the late 1980s, a handful of different approaches to in vivo pretargeting have been developed, including strategies based on bispecific antibodies, the interaction between streptavidin and biotin, and the hybridization of complementary oligonucleotides14,15,16,17,18. Yet each has been held back to varying degrees by complications, most famously the potent immunogenicity of streptavidin-modified antibodies19,20. Over the last five years, our group and others have developed an approach to in vivo pretargeting based on the rapid and bioorthogonal inverse electron demand Diels-Alder ligation between trans-cyclooctene (TCO) and tetrazine (Tz)21,22,23,24. The most successful of these strategies have employed a TCO-modified antibody and a Tz-bearing radioligand, as TCO is typically more stable in vivo than its Tz partner (Figure 1)25,26. As in other pretargeting methodologies, the mAb-TCO immunoconjugate is administered first and given time to clear from circulation and accumulate in tumor tissue. Subsequently, the small molecule Tz radioligand is injected, after which it either clicks with the immunoconjugate within the target tissue or clears rapidly from the body. This in vivo pretargeting strategy has proven highly effective for PET and SPECT imaging with several different antibody/antigen systems, consistently producing images with high contrast and enabling the use of short-lived radionuclides such as 18F (t&#189; = 109 min) and 64Cu (t1/2 = 12.7 h)21,22,24. More recently, the efficacy of click-based pretargeted radioimmunotherapy (PRIT) has been demonstrated in murine models of pancreatic ductal adenocarcinoma (PDAC) and colorectal carcinoma27,28. To this end, the therapeutic radionuclide 177Lu (&#946;max = 498 keV, t1/2 = 6.7 days) was employed in conjunction with two different antibodies: 5B1, which targets carbohydrate antigen 19.9 (CA19.9) ubiquitously expressed in PDAC, and huA33, which targets A33, a transmembrane glycoprotein expressed in &#62;95% of colorectal cancers. In both cases, this approach to 177Lu-PRIT yielded high activity concentrations in tumor tissue, created a dose-dependent therapeutic effect, and simultaneously reduced activity concentrations in healthy tissues compared to traditional directly-labeled radioimmunoconjugates.
In this article, we describe protocols for PRIT using a 177Lu-DOTA-labeled tetrazine radioligand ([177Lu]Lu-DOTA-PEG7-Tz) and a TCO-modified variant of the huA33 antibody (huA33-TCO). More specifically, we describe the construction of huA33-TCO (Figure 2), the synthesis and radiolabeling of [177Lu]Lu-DOTA-PEG7-Tz (Figure 3 and Figure 4), and the performance of in vivo biodistribution and longitudinal therapy studies in murine models of colorectal carcinoma. Furthermore, in the representative results and discussion, we present a sample data set, address possible strategies for the optimization of this approach, and consider this strategy in the wider context of in vivo pretargeting and PRIT. Finally, it is important to note that while we have chosen to focus on pretargeting using huA33-TCO and [177Lu]Lu-DOTA-PEG7-Tz in this protocol, this strategy is highly modular and can be adapted to suit a wide range of antibodies and radionuclides.

<table>
	<tbody>
		<tr>
			<td>(E)-Cyclooct-4-enyl 2,5-dioxo-1-pyrrolidinyl carbonate (TCO-NHS)</td>
			<td>Sigma-Aldrich</td>
			<td>764523</td>
			<td>Store at -80 &#176;C</td>
		</tr>
		<tr>
			<td>2,5-Dioxo-1-pyrrolidinyl 5-[4-(1,2,4,5-tetrazin-3-yl)benzylamino]-5-oxopentanoate (Tz-NHS)</td>
			<td>Sigma-Aldrich</td>
			<td>764701</td>
			<td>Store at -80 &#176;C</td>
		</tr>
		<tr>
			<td>Acetonitrile (MeCN)</td>
			<td>Fisher Scientific</td>
			<td>A998-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium Acetate (NH4OAc)</td>
			<td>Fisher Scientific</td>
			<td>A639-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Boc-PEG7-amine (O-(2-Aminoethyl)-O&#8242;-[2-(Boc-amino)ethyl]hexaethylene glycol)</td>
			<td>Sigma-Aldrich</td>
			<td>70023</td>
			<td>Store at -20 &#176;C</td>
		</tr>
		<tr>
			<td>Dichloromethane (DCM)</td>
			<td>Fisher Scientific</td>
			<td>D143-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide (DMSO), anhydrous</td>
			<td>Fisher Scientific</td>
			<td>D12345</td>
			<td></td>
		</tr>
		<tr>
			<td>EMD Millipore Amicon Ultra-2 Centrifugal Filter Unit</td>
			<td>Fisher Scientific</td>
			<td>UFC205024</td>
			<td></td>
		</tr>
		<tr>
			<td>GE Healthcare Disposable PD-10 Desalting Columns</td>
			<td>Fisher Scientific</td>
			<td>45-000-148</td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-Dimethylformamide (DMF), anhydrous</td>
			<td>Fisher Scientific</td>
			<td>AC610941000</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline (PBS)</td>
			<td>Fisher Scientific</td>
			<td>70-011-044</td>
			<td>10x Concentrated</td>
		</tr>
		<tr>
			<td>p-SCN-Bn-DOTA</td>
			<td>Macrocyclics</td>
			<td>B-205</td>
			<td>Store at -20 &#176;C</td>
		</tr>
		<tr>
			<td>Triethylamine (TEA)</td>
			<td>Fisher Scientific</td>
			<td>AC157911000</td>
			<td></td>
		</tr>
		<tr>
			<td>Trifluoroacetic Acid (TFA)</td>
			<td>Fisher Scientific</td>
			<td>A116-50</td>
			<td></td>
		</tr>
		<tr>
			<td>Tumor measuring device</td>
			<td>Peira TM900</td>
			<td>Peira TM900</td>
			<td></td>
		</tr>
	</tbody>
</table>

pretargeted radioimmunotherapy based on the inverse electron demand diels-alder reaction

While radioimmunotherapy (RIT) is a promising approach for the treatment of cancer, the long pharmacokinetic half-life of radiolabeled antibodies can result in high radiation doses to healthy tissues. Perhaps not surprisingly, several different strategies have been developed to circumvent this troubling limitation. One of the most promising of these approaches is pretargeted radioimmunotherapy (PRIT). PRIT is predicated on decoupling the radionuclide from the immunoglobulin, injecting them separately, and then allowing them to combine in vivo at the target tissue. This approach harnesses the exceptional tumor-targeting properties of antibodies while skirting their pharmacokinetic drawbacks, thereby lowering radiation doses to non-target tissues and facilitating the use of radionuclides with half-lives that are considered too short for use in traditional radioimmunoconjugates. Over the last five years, our laboratory and others have developed an approach to in vivo pretargeting based on the inverse electron-demand Diels-Alder (IEDDA) reaction between trans-cyclooctene (TCO) and tetrazine (Tz). This strategy has been successfully applied to pretargeted positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging with a variety of antibody-antigen systems. In a pair of recent publications, we have demonstrated the efficacy of IEDDA-based PRIT in murine models of pancreatic ductal adenocarcinoma and colorectal carcinoma. In this protocol, we describe protocols for PRIT using a 177Lu-DOTA-labeled tetrazine radioligand ([177Lu]Lu-DOTA-PEG7-Tz) and a TCO-modified variant of the colorectal cancer targeting huA33 antibody (huA33-TCO). More specifically, we will describe the construction of huA33-TCO, the synthesis and radiolabeling of [177Lu]Lu-DOTA-PEG7-Tz, and the performance of in vivo biodistribution and longitudinal therapy studies in murine models of colorectal carcinoma.

The conjugation of TCO to huA33 is predicated on the coupling between the amine-reactive TCO-NHS and the lysine residues on the surface of the immunoglobulin. This method is highly robust and reproducible and reliably yields a degree-of-labeling of 2-4 TCO/mAb. In this case, MALDI-ToF mass spectrometry was employed to confirm a degree of labeling of approximately 4.0 TCO/mAb; a similar value was obtained using a fluorophore-modified tetrazine as a reporter24. The s...

Watch this Scientific Journal Video about Pretargeted Radioimmunotherapy Based on the Inverse Electron Demand Diels-Alder Reaction at JoVE.com

Pretargeted Radioimmunotherapy Based on the Inverse Electron Demand Diels-Alder Reaction

This protocol describes the synthesis and characterization of a trans-cyclooctene (TCO)-modified antibody and a 177Lu-labeled tetrazine (Tz) radioligand for pretargeted radioimmunotherapy (PRIT). In addition, it details the use of these two constructs for in vivo biodistribution and longitudinal therapy studies in a murine model of colorectal cancer.

While radioimmunotherapy (RIT) is a promising approach for the treatment of cancer, the long pharmacokinetic half-life of radiolabeled antibodies can ...

Research

JoVE Journal

Chemistry

Microwave-assisted Intramolecular Dehydrogenative Diels-Alder Reactions for the Synthesis of Functionalized Naphthalenes/Solvatochromic Dyes

Functionalized naphthalenes have applications in a variety of research fields ranging from the synthesis of natural or biologically active molecules to ...

Microfluidic On-chip Capture-cycloaddition Reaction to Reversibly Immobilize Small Molecules or Multi-component Structures for Biosensor Applications

Methods  for rapid surface immobilization of bioactive small molecules with control over  orientation and immobilization density are highly desirable for ...

Determining the Ice-binding Planes of Antifreeze Proteins by Fluorescence-based Ice Plane Affinity

Antifreeze proteins (AFPs) are expressed in a variety of cold-hardy organisms to prevent or slow internal ice growth. AFPs bind to specific planes of ice ...

Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. ...

An Inverse Analysis Approach to the Characterization of Chemical Transport in Paints

The ability to directly characterize chemical transport and interactions that occur within a material (i.e., subsurface dynamics) is a vital component in ...

1,3,5-Triphenylbenzene and Corannulene as Electron Receptors for Lithium Solvated Electron Solutions

The authors report on conductivity studies carried out on lithium solvated electron solutions (LiSES) prepared using two types of polyaromatic ...

The Preparation and Properties of Thermo-reversibly Cross-linked Rubber Via Diels-Alder Chemistry

A method for using Diels Alder thermo-reversible chemistry as cross-linking tool for rubber products is demonstrated. In this work, a commercial ...

A Rapid Synthesis Method for Au, Pd, and Pt Aerogels Via Direct Solution-Based Reduction

Here, a method to synthesize gold, palladium, and platinum aerogels via a rapid, direct solution-based reduction is presented. The combination of various ...

Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis

A novel elemental and chemical analysis scheme based on electron-channeling phenomena in crystalline materials is introduced, where the incident ...

Picometer-Precision Atomic Position Tracking through Electron Microscopy

The modern aberration-corrected scanning transmission electron microscopes (AC-STEM) have successfully achieved direct visualization of atomic columns ...