Toward in vivo proof of binding of 18F-labeled inhibitor [18F]TRACK to peripheral tropomyosin receptor kinases
Abstract Background Tropomyosin receptor kinases (TrkA, TrkB, TrkC) are a family of tyrosine kinases primarily expressed in neuronal cells of the brain. Identification of oncogenic alterations in Trk expression as a driver in multiple tumor types has increased interest in their role in human cancers...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-07-01
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| Series: | EJNMMI Research |
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| Online Access: | https://doi.org/10.1186/s13550-022-00915-w |
| _version_ | 1828375176297840640 |
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| author | Melinda Wuest Justin J. Bailey Jennifer Dufour Darryl Glubrecht Vanessa Omana Tom H. Johnston Jonathan M. Brotchie Ralf Schirrmacher |
| author_facet | Melinda Wuest Justin J. Bailey Jennifer Dufour Darryl Glubrecht Vanessa Omana Tom H. Johnston Jonathan M. Brotchie Ralf Schirrmacher |
| author_sort | Melinda Wuest |
| collection | DOAJ |
| description | Abstract Background Tropomyosin receptor kinases (TrkA, TrkB, TrkC) are a family of tyrosine kinases primarily expressed in neuronal cells of the brain. Identification of oncogenic alterations in Trk expression as a driver in multiple tumor types has increased interest in their role in human cancers. Recently, first- and second-generation 11C and 18F-labeled Trk inhibitors, e.g., [18F]TRACK, have been developed. The goal of the present study was to analyze the direct interaction of [18F]TRACK with peripheral Trk receptors in vivo to prove its specificity for use as a functional imaging probe. Methods In vitro uptake and competition experiments were carried out using the colorectal cancer cell line KM12. Dynamic PET experiments were performed with [18F]TRACK, either alone or in the presence of amitriptyline, an activator of Trk, entrectinib, a Trk inhibitor, or unlabeled reference compound TRACK in KM12 tumor-bearing athymic nude mice as well as B6129SF2/J and corresponding B6;129S2-Ntrk2 tm1Bbd /J mice. Western blot and immunohistochemistry experiments were done with KM12 tumors, brown adipose tissue (BAT), and brain tissue samples. Results Uptake of [18F]TRACK was increasing over time reaching 208 ± 72% radioactivity per mg protein (n = 6/2) after 60 min incubation time. Entrectinib and TRACK competitively blocked [18F]TRACK uptake in vitro (IC50 30.9 ± 3.6 and 29.4 ± 9.4 nM; both n = 6/2). [18F]TRACK showed uptake into KM12 tumors (SUVmean,60 min 0.43 ± 0.03; n = 6). Tumor-to-muscle ratio reached 0.9 (60 min) and 1.2 (120 min). In TrkB expressing BAT, [18F]TRACK uptake reached SUVmean,60 min 1.32 ± 0.08 (n = 7). Activation of Trk through amitriptyline resulted in a significant radioactivity increase of 21% in KM12 tumor (SUVmean,60 min from 0.53 ± 0.01 to 0.43 ± 0.03; n = 6; p < 0.05) and of 21% in BAT (SUVmean,60 min from 1.32 ± 0.08; n = 5 to 1.59 ± 0.07; n = 6; p < 0.05) respectively. Immunohistochemistry showed TrkB > TrkA expression on BAT fat cells, but TrkA > TrkB in whole brain. WB analysis showed sevenfold higher TrkB expression in BAT versus KM12 tumor tissue. Conclusion The present data show that radiotracer [18F]TRACK can target peripheral Trk receptors in human KM12 colon cancer as well as brown adipose tissue as confirmed through in vitro and in vivo blocking experiments. Higher TrkB versus TrkA protein expression was detected in brown adipose tissue of mice confirming a peripheral functional role of brain-derived neurotrophic factor in adipose tissue. |
| first_indexed | 2024-04-14T07:44:04Z |
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| institution | Directory Open Access Journal |
| issn | 2191-219X |
| language | English |
| last_indexed | 2024-04-14T07:44:04Z |
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| spelling | doaj.art-3dc92fdbba9e4cf8974624c528cb9b862022-12-22T02:05:24ZengSpringerOpenEJNMMI Research2191-219X2022-07-0112111610.1186/s13550-022-00915-wToward in vivo proof of binding of 18F-labeled inhibitor [18F]TRACK to peripheral tropomyosin receptor kinasesMelinda Wuest0Justin J. Bailey1Jennifer Dufour2Darryl Glubrecht3Vanessa Omana4Tom H. Johnston5Jonathan M. Brotchie6Ralf Schirrmacher7Department of Oncology, Cross Cancer Institute, University of AlbertaDepartment of Oncology, Cross Cancer Institute, University of AlbertaDepartment of Oncology, Cross Cancer Institute, University of AlbertaDepartment of Oncology, Cross Cancer Institute, University of AlbertaThe Neuro - Montreal Neurological Institute-Hospital, McGill UniversityKrembil Research Institute, University Health NetworkKrembil Research Institute, University Health NetworkDepartment of Oncology, Cross Cancer Institute, University of AlbertaAbstract Background Tropomyosin receptor kinases (TrkA, TrkB, TrkC) are a family of tyrosine kinases primarily expressed in neuronal cells of the brain. Identification of oncogenic alterations in Trk expression as a driver in multiple tumor types has increased interest in their role in human cancers. Recently, first- and second-generation 11C and 18F-labeled Trk inhibitors, e.g., [18F]TRACK, have been developed. The goal of the present study was to analyze the direct interaction of [18F]TRACK with peripheral Trk receptors in vivo to prove its specificity for use as a functional imaging probe. Methods In vitro uptake and competition experiments were carried out using the colorectal cancer cell line KM12. Dynamic PET experiments were performed with [18F]TRACK, either alone or in the presence of amitriptyline, an activator of Trk, entrectinib, a Trk inhibitor, or unlabeled reference compound TRACK in KM12 tumor-bearing athymic nude mice as well as B6129SF2/J and corresponding B6;129S2-Ntrk2 tm1Bbd /J mice. Western blot and immunohistochemistry experiments were done with KM12 tumors, brown adipose tissue (BAT), and brain tissue samples. Results Uptake of [18F]TRACK was increasing over time reaching 208 ± 72% radioactivity per mg protein (n = 6/2) after 60 min incubation time. Entrectinib and TRACK competitively blocked [18F]TRACK uptake in vitro (IC50 30.9 ± 3.6 and 29.4 ± 9.4 nM; both n = 6/2). [18F]TRACK showed uptake into KM12 tumors (SUVmean,60 min 0.43 ± 0.03; n = 6). Tumor-to-muscle ratio reached 0.9 (60 min) and 1.2 (120 min). In TrkB expressing BAT, [18F]TRACK uptake reached SUVmean,60 min 1.32 ± 0.08 (n = 7). Activation of Trk through amitriptyline resulted in a significant radioactivity increase of 21% in KM12 tumor (SUVmean,60 min from 0.53 ± 0.01 to 0.43 ± 0.03; n = 6; p < 0.05) and of 21% in BAT (SUVmean,60 min from 1.32 ± 0.08; n = 5 to 1.59 ± 0.07; n = 6; p < 0.05) respectively. Immunohistochemistry showed TrkB > TrkA expression on BAT fat cells, but TrkA > TrkB in whole brain. WB analysis showed sevenfold higher TrkB expression in BAT versus KM12 tumor tissue. Conclusion The present data show that radiotracer [18F]TRACK can target peripheral Trk receptors in human KM12 colon cancer as well as brown adipose tissue as confirmed through in vitro and in vivo blocking experiments. Higher TrkB versus TrkA protein expression was detected in brown adipose tissue of mice confirming a peripheral functional role of brain-derived neurotrophic factor in adipose tissue.https://doi.org/10.1186/s13550-022-00915-wTrkATrkBPETMolecular imagingRadiotracer[18F]TRACK |
| spellingShingle | Melinda Wuest Justin J. Bailey Jennifer Dufour Darryl Glubrecht Vanessa Omana Tom H. Johnston Jonathan M. Brotchie Ralf Schirrmacher Toward in vivo proof of binding of 18F-labeled inhibitor [18F]TRACK to peripheral tropomyosin receptor kinases EJNMMI Research TrkA TrkB PET Molecular imaging Radiotracer [18F]TRACK |
| title | Toward in vivo proof of binding of 18F-labeled inhibitor [18F]TRACK to peripheral tropomyosin receptor kinases |
| title_full | Toward in vivo proof of binding of 18F-labeled inhibitor [18F]TRACK to peripheral tropomyosin receptor kinases |
| title_fullStr | Toward in vivo proof of binding of 18F-labeled inhibitor [18F]TRACK to peripheral tropomyosin receptor kinases |
| title_full_unstemmed | Toward in vivo proof of binding of 18F-labeled inhibitor [18F]TRACK to peripheral tropomyosin receptor kinases |
| title_short | Toward in vivo proof of binding of 18F-labeled inhibitor [18F]TRACK to peripheral tropomyosin receptor kinases |
| title_sort | toward in vivo proof of binding of 18f labeled inhibitor 18f track to peripheral tropomyosin receptor kinases |
| topic | TrkA TrkB PET Molecular imaging Radiotracer [18F]TRACK |
| url | https://doi.org/10.1186/s13550-022-00915-w |
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