Development of the first CDK7 specific PET imaging probe based on a carbon-11 labeled pyrazolotriazine derivative for visualization of glioblastoma. Bihler, J., Martin-Armas, M., Guttormsen, Y., Lindemann, M., Oteiza, A., Sundset, R., Moldes-Anaya, A., & Kranz, M. Journal of Nuclear Medicine, 62(supplement 1):1456–1456, Society of Nuclear Medicine, 2021. ![Development of the first CDK7 specific PET imaging probe based on a carbon-11 labeled pyrazolotriazine derivative for visualization of glioblastoma [link]](https://bibbase.org/img/filetypes/link.svg "link")
Paper abstract bibtex 1 download 1456Introduction: Glioblastoma (GBM) represents the deadliest type of malignancies of the central nervous system. Major challenges such as critical brain locations, the lack of defined tumor margins and heterogeneity, contribute to inevitable tumor recurrence. However, the elucidation of the genomic profile of GBM has enabled the development of receptor specific drugs.1 Among others Cyclin-Dependent Kinase 7 (CDK7) is overexpressed in GBM and may be an interesting target for imaging and diagnosis due to its role in cell proliferation and tumor progression.2 A specific radiotracer for positron emission tomography (PET) might be beneficial in pathological characterization and tumor grading to tailor future treatments to individual tumor profiles. Among published structures the pyrazolotriazine inhibitor LCD3140 represents a potential tracer capable of crossing the blood-brain barrier (BBB).3 Here we describe the synthesis and first successful radiolabeling of this compound. Methods: The pyrazolotriazine standard 1 and precursor 2 for radiosynthesis were prepared in a 7 to 8-step synthetic pathway. Radiosynthesis of [11C]1 was performed by radiomethylation with [11C]MeOTf using tetramethylpiperidine (TMP) as a base in dimethylformamide (DMF) at 85°C for 4 min in a TRACERLAB FX2 C semiautomatic module with a X-Select C18 semipreparative column. The purified fraction was diluted, trapped onto a C18 SPE cartridge, eluted with ethanol, preconcentrated and formulated in isotonic saline. CDK7 Western Blot (WB) analysis in mouse (GL261, GL261 Luc2) and human GBM cell lines (U251) was performed to investigate CDK7 expression. Therefore, whole cell lysates were prepared, 50 μg of total protein was separated by gel electrophoresis, transferred to a nitrocellulose membrane and examined with CDK7 and HRP-linked antibody, respectively. Results: Non-radioactive pyrazolotriazine 1 and the precursor 2 were obtained in 7% and 5% overall yields with a purity of >99%. Radiomethylation of 2 with [11C]MeOTf resulted in [11C]1 with 19% (n=1) radiochemical yield (RCY, non-decay corrected, EOB), radiochemical purity (RCP) >99%, molar activity (Am) of 121 GBq/\textmumol (n=1) and a total synthesis time of 44 min. CDK7 expression was confirmed in GL261, GL261 Luc2 and U251 cells by Western Blotting rendering the resp. cell lines as suitable for further in vitro and in vivo studies with [11C]1. Conclusion: To our knowledge, the first 11C-labeled radiotracer for CDK7 imaging was successfully synthesized with high RCY, RCP and Am. In addition, we used WB to select appropriate cell lines for further investigation of the radiotracer for in vivo PET imaging. Therefore, studies with brain tumor bearing mice are planned to confirm BBB penetration, metabolic stability and specific binding in GBM under LDC3140 inhibition. Subsequently, the radiotracer will be further developed as tool for CDK7 imaging in brain tumor with PET and therapy monitoring in combined therapy approaches. References: 1 Vleeschouwer S, Glioblastoma. Brisbane (AU); 2017. 2 Meng W, et al. CDK7 inhibition is a novel therapeutic strategy against GBM both in-vitro and in-vivo. Cancer Manag Res. 2018. 3 Eickhoff J, Lead Discovery Center GmbH. Pyrazolo-triazine derivatives as selective cyclin-dependent kinase inhibitors. DE WO 2013/128028 Acknowledgements: This study is financed by 180°N the Norwegian Nuclear Medicine Consortium
@article {Bihler1456,
author = {Bihler, Julia and Martin-Armas, Montserrat and Guttormsen, Yngve and Lindemann, Marcel and Oteiza, Ana and Sundset, Rune and Moldes-Anaya, Angel and Kranz, Mathias},
title = {Development of the first CDK7 specific PET imaging probe based on a carbon-11 labeled pyrazolotriazine derivative for visualization of glioblastoma},
volume = {62},
number = {supplement 1},
pages = {1456--1456},
year = {2021},
publisher = {Society of Nuclear Medicine},
abstract = {1456Introduction: Glioblastoma (GBM) represents the deadliest type of malignancies of the central nervous system. Major challenges such as critical brain locations, the lack of defined tumor margins and heterogeneity, contribute to inevitable tumor recurrence. However, the elucidation of the genomic profile of GBM has enabled the development of receptor specific drugs.1 Among others Cyclin-Dependent Kinase 7 (CDK7) is overexpressed in GBM and may be an interesting target for imaging and diagnosis due to its role in cell proliferation and tumor progression.2 A specific radiotracer for positron emission tomography (PET) might be beneficial in pathological characterization and tumor grading to tailor future treatments to individual tumor profiles. Among published structures the pyrazolotriazine inhibitor LCD3140 represents a potential tracer capable of crossing the blood-brain barrier (BBB).3 Here we describe the synthesis and first successful radiolabeling of this compound. Methods: The pyrazolotriazine standard 1 and precursor 2 for radiosynthesis were prepared in a 7 to 8-step synthetic pathway. Radiosynthesis of [11C]1 was performed by radiomethylation with [11C]MeOTf using tetramethylpiperidine (TMP) as a base in dimethylformamide (DMF) at 85{\textdegree}C for 4 min in a TRACERLAB FX2 C semiautomatic module with a X-Select C18 semipreparative column. The purified fraction was diluted, trapped onto a C18 SPE cartridge, eluted with ethanol, preconcentrated and formulated in isotonic saline. CDK7 Western Blot (WB) analysis in mouse (GL261, GL261 Luc2) and human GBM cell lines (U251) was performed to investigate CDK7 expression. Therefore, whole cell lysates were prepared, 50 μg of total protein was separated by gel electrophoresis, transferred to a nitrocellulose membrane and examined with CDK7 and HRP-linked antibody, respectively. Results: Non-radioactive pyrazolotriazine 1 and the precursor 2 were obtained in 7\% and 5\% overall yields with a purity of \>99\%. Radiomethylation of 2 with [11C]MeOTf resulted in [11C]1 with 19\% (n=1) radiochemical yield (RCY, non-decay corrected, EOB), radiochemical purity (RCP) \>99\%, molar activity (Am) of 121 GBq/{\textmu}mol (n=1) and a total synthesis time of 44 min. CDK7 expression was confirmed in GL261, GL261 Luc2 and U251 cells by Western Blotting rendering the resp. cell lines as suitable for further in vitro and in vivo studies with [11C]1. Conclusion: To our knowledge, the first 11C-labeled radiotracer for CDK7 imaging was successfully synthesized with high RCY, RCP and Am. In addition, we used WB to select appropriate cell lines for further investigation of the radiotracer for in vivo PET imaging. Therefore, studies with brain tumor bearing mice are planned to confirm BBB penetration, metabolic stability and specific binding in GBM under LDC3140 inhibition. Subsequently, the radiotracer will be further developed as tool for CDK7 imaging in brain tumor with PET and therapy monitoring in combined therapy approaches. References: 1 Vleeschouwer S, Glioblastoma. Brisbane (AU); 2017. 2 Meng W, et al. CDK7 inhibition is a novel therapeutic strategy against GBM both in-vitro and in-vivo. Cancer Manag Res. 2018. 3 Eickhoff J, Lead Discovery Center GmbH. Pyrazolo-triazine derivatives as selective cyclin-dependent kinase inhibitors. DE WO 2013/128028 Acknowledgements: This study is financed by 180{\textdegree}N the Norwegian Nuclear Medicine Consortium},
issn = {0161-5505},
URL = {https://jnm.snmjournals.org/content/62/supplement_1/1456},
journal = {Journal of Nuclear Medicine}
}
Downloads: 1
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Major challenges such as critical brain locations, the lack of defined tumor margins and heterogeneity, contribute to inevitable tumor recurrence. However, the elucidation of the genomic profile of GBM has enabled the development of receptor specific drugs.1 Among others Cyclin-Dependent Kinase 7 (CDK7) is overexpressed in GBM and may be an interesting target for imaging and diagnosis due to its role in cell proliferation and tumor progression.2 A specific radiotracer for positron emission tomography (PET) might be beneficial in pathological characterization and tumor grading to tailor future treatments to individual tumor profiles. Among published structures the pyrazolotriazine inhibitor LCD3140 represents a potential tracer capable of crossing the blood-brain barrier (BBB).3 Here we describe the synthesis and first successful radiolabeling of this compound. Methods: The pyrazolotriazine standard 1 and precursor 2 for radiosynthesis were prepared in a 7 to 8-step synthetic pathway. Radiosynthesis of [11C]1 was performed by radiomethylation with [11C]MeOTf using tetramethylpiperidine (TMP) as a base in dimethylformamide (DMF) at 85°C for 4 min in a TRACERLAB FX2 C semiautomatic module with a X-Select C18 semipreparative column. The purified fraction was diluted, trapped onto a C18 SPE cartridge, eluted with ethanol, preconcentrated and formulated in isotonic saline. CDK7 Western Blot (WB) analysis in mouse (GL261, GL261 Luc2) and human GBM cell lines (U251) was performed to investigate CDK7 expression. Therefore, whole cell lysates were prepared, 50 μg of total protein was separated by gel electrophoresis, transferred to a nitrocellulose membrane and examined with CDK7 and HRP-linked antibody, respectively. Results: Non-radioactive pyrazolotriazine 1 and the precursor 2 were obtained in 7% and 5% overall yields with a purity of >99%. Radiomethylation of 2 with [11C]MeOTf resulted in [11C]1 with 19% (n=1) radiochemical yield (RCY, non-decay corrected, EOB), radiochemical purity (RCP) >99%, molar activity (Am) of 121 GBq/\\textmumol (n=1) and a total synthesis time of 44 min. CDK7 expression was confirmed in GL261, GL261 Luc2 and U251 cells by Western Blotting rendering the resp. cell lines as suitable for further in vitro and in vivo studies with [11C]1. Conclusion: To our knowledge, the first 11C-labeled radiotracer for CDK7 imaging was successfully synthesized with high RCY, RCP and Am. In addition, we used WB to select appropriate cell lines for further investigation of the radiotracer for in vivo PET imaging. Therefore, studies with brain tumor bearing mice are planned to confirm BBB penetration, metabolic stability and specific binding in GBM under LDC3140 inhibition. Subsequently, the radiotracer will be further developed as tool for CDK7 imaging in brain tumor with PET and therapy monitoring in combined therapy approaches. References: 1 Vleeschouwer S, Glioblastoma. Brisbane (AU); 2017. 2 Meng W, et al. CDK7 inhibition is a novel therapeutic strategy against GBM both in-vitro and in-vivo. Cancer Manag Res. 2018. 3 Eickhoff J, Lead Discovery Center GmbH. Pyrazolo-triazine derivatives as selective cyclin-dependent kinase inhibitors. DE WO 2013/128028 Acknowledgements: This study is financed by 180°N the Norwegian Nuclear Medicine Consortium","issn":"0161-5505","url":"https://jnm.snmjournals.org/content/62/supplement_1/1456","journal":"Journal of Nuclear Medicine","bibtex":"@article {Bihler1456,\n\tauthor = {Bihler, Julia and Martin-Armas, Montserrat and Guttormsen, Yngve and Lindemann, Marcel and Oteiza, Ana and Sundset, Rune and Moldes-Anaya, Angel and Kranz, Mathias},\n\ttitle = {Development of the first CDK7 specific PET imaging probe based on a carbon-11 labeled pyrazolotriazine derivative for visualization of glioblastoma},\n\tvolume = {62},\n\tnumber = {supplement 1},\n\tpages = {1456--1456},\n\tyear = {2021},\n\tpublisher = {Society of Nuclear Medicine},\n\tabstract = {1456Introduction: Glioblastoma (GBM) represents the deadliest type of malignancies of the central nervous system. Major challenges such as critical brain locations, the lack of defined tumor margins and heterogeneity, contribute to inevitable tumor recurrence. However, the elucidation of the genomic profile of GBM has enabled the development of receptor specific drugs.1 Among others Cyclin-Dependent Kinase 7 (CDK7) is overexpressed in GBM and may be an interesting target for imaging and diagnosis due to its role in cell proliferation and tumor progression.2 A specific radiotracer for positron emission tomography (PET) might be beneficial in pathological characterization and tumor grading to tailor future treatments to individual tumor profiles. Among published structures the pyrazolotriazine inhibitor LCD3140 represents a potential tracer capable of crossing the blood-brain barrier (BBB).3 Here we describe the synthesis and first successful radiolabeling of this compound. Methods: The pyrazolotriazine standard 1 and precursor 2 for radiosynthesis were prepared in a 7 to 8-step synthetic pathway. Radiosynthesis of [11C]1 was performed by radiomethylation with [11C]MeOTf using tetramethylpiperidine (TMP) as a base in dimethylformamide (DMF) at 85{\\textdegree}C for 4 min in a TRACERLAB FX2 C semiautomatic module with a X-Select C18 semipreparative column. The purified fraction was diluted, trapped onto a C18 SPE cartridge, eluted with ethanol, preconcentrated and formulated in isotonic saline. CDK7 Western Blot (WB) analysis in mouse (GL261, GL261 Luc2) and human GBM cell lines (U251) was performed to investigate CDK7 expression. Therefore, whole cell lysates were prepared, 50 μg of total protein was separated by gel electrophoresis, transferred to a nitrocellulose membrane and examined with CDK7 and HRP-linked antibody, respectively. Results: Non-radioactive pyrazolotriazine 1 and the precursor 2 were obtained in 7\\% and 5\\% overall yields with a purity of \\>99\\%. Radiomethylation of 2 with [11C]MeOTf resulted in [11C]1 with 19\\% (n=1) radiochemical yield (RCY, non-decay corrected, EOB), radiochemical purity (RCP) \\>99\\%, molar activity (Am) of 121 GBq/{\\textmu}mol (n=1) and a total synthesis time of 44 min. CDK7 expression was confirmed in GL261, GL261 Luc2 and U251 cells by Western Blotting rendering the resp. cell lines as suitable for further in vitro and in vivo studies with [11C]1. Conclusion: To our knowledge, the first 11C-labeled radiotracer for CDK7 imaging was successfully synthesized with high RCY, RCP and Am. In addition, we used WB to select appropriate cell lines for further investigation of the radiotracer for in vivo PET imaging. Therefore, studies with brain tumor bearing mice are planned to confirm BBB penetration, metabolic stability and specific binding in GBM under LDC3140 inhibition. Subsequently, the radiotracer will be further developed as tool for CDK7 imaging in brain tumor with PET and therapy monitoring in combined therapy approaches. References: 1 Vleeschouwer S, Glioblastoma. Brisbane (AU); 2017. 2 Meng W, et al. CDK7 inhibition is a novel therapeutic strategy against GBM both in-vitro and in-vivo. Cancer Manag Res. 2018. 3 Eickhoff J, Lead Discovery Center GmbH. Pyrazolo-triazine derivatives as selective cyclin-dependent kinase inhibitors. 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