1
|
PI3K/mTOR Dual Inhibitor Pictilisib Stably Binds to Site I of Human Serum Albumin as Observed by Computer Simulation, Multispectroscopic, and Microscopic Studies. Molecules 2022; 27:molecules27165071. [PMID: 36014303 PMCID: PMC9413508 DOI: 10.3390/molecules27165071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/02/2022] [Accepted: 08/06/2022] [Indexed: 11/17/2022] Open
Abstract
Pictilisib (GDC-0941) is a well-known dual inhibitor of class I PI3K and mTOR and is presently undergoing phase 2 clinical trials for cancer treatment. The present work investigated the dynamic behaviors and interaction mechanism between GDC-0941 and human serum albumin (HSA). Molecular docking and MD trajectory analyses revealed that GDC-0941 bound to HSA and that the binding site was positioned in subdomain IIA at Sudlow’s site I of HSA. The fluorescence intensity of HSA was strongly quenched by GDC-0941, and results showed that the HSA–GDC-0941 interaction was a static process caused by ground-state complex formation. The association constant of the HSA–GDC-0941 complex was approximately 105 M−1, reflecting moderate affinity. Thermodynamic analysis conclusions were identical with MD simulation results, which revealed that van der Waals interactions were the vital forces involved in the binding process. CD, synchronous, and 3D fluorescence spectroscopic results revealed that GDC-0941 induced the structural change in HSA. Moreover, the conformational change of HSA affected its molecular sizes, as evidenced by AFM. This work provides a useful research strategy for exploring the interaction of GDC-0941 with HSA, thus helping in the understanding of the transport and delivery of dual inhibitors in the blood circulation system.
Collapse
|
2
|
China’s radiopharmaceuticals on expressway: 2014–2021. RADIOCHIM ACTA 2022. [DOI: 10.1515/ract-2021-1137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
This review provides an essential overview on the progress of rapidly-developing China’s radiopharmaceuticals in recent years (2014–2021). Our discussion reflects on efforts to develop potential, preclinical, and in-clinical radiopharmaceuticals including the following areas: (1) brain imaging agents, (2) cardiovascular imaging agents, (3) infection and inflammation imaging agents, (4) tumor radiopharmaceuticals, and (5) boron delivery agents (a class of radiopharmaceutical prodrug) for neutron capture therapy. Especially, the progress in basic research, including new radiolabeling methodology, is highlighted from a standpoint of radiopharmaceutical chemistry. Meanwhile, we briefly reflect on the recent major events related to radiopharmaceuticals along with the distribution of major R&D forces (universities, institutions, facilities, and companies), clinical study status, and national regulatory supports. We conclude with a brief commentary on remaining limitations and emerging opportunities for China’s radiopharmaceuticals.
Collapse
|
3
|
Jin C, Luo X, Li X, Zhou R, Zhong Y, Xu Z, Cui C, Xing X, Zhang H, Tian M. Positron emission tomography molecular imaging-based cancer phenotyping. Cancer 2022; 128:2704-2716. [PMID: 35417604 PMCID: PMC9324101 DOI: 10.1002/cncr.34228] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/06/2022] [Accepted: 03/09/2022] [Indexed: 12/28/2022]
Abstract
During the past several decades, numerous studies have provided insights into biological characteristics of cancer cells and identified various hallmarks of cancer acquired in the tumorigenic processes. However, it is still challenging to image these distinctive traits of cancer to facilitate the management of patients in clinical settings. The rapidly evolving field of positron emission tomography (PET) imaging has provided opportunities to investigate cancer's biological characteristics in vivo. This article reviews the current status of PET imaging on characterizing hallmarks of cancer and discusses the future directions of PET imaging strategies facilitating in vivo cancer phenotyping. Various direct and indirect imaging strategies have been developed in positron emission tomography. Positron emission tomography has shown great potential in characterizing cancer hallmarks in vivo.
Collapse
Affiliation(s)
- Chentao Jin
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Xiaoyun Luo
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Xiaoyi Li
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Rui Zhou
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Yan Zhong
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Zhoujiao Xu
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Chunyi Cui
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Xiaoqing Xing
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Hong Zhang
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China.,College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.,Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China
| | - Mei Tian
- Department of Nuclear Medicine and Positron Emission Tomography Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| |
Collapse
|
4
|
Bilgi A, Yurt Kilcar A, Gokulu SG, Kayas C, Yildirim N, Karatay KB, Akman L, Biber Muftuler FZ, Ozsaran AA. mTOR inhibitors from a diagnostic perspective: radiolabeling of everolimus and its nanoformulation, in vitro incorporation assays against cervix and ovarian cancer cells. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-08066-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
5
|
Hu F, Gong C, Gai Y, Jiang D, Liu Q, Wang S, Hu M, Pi R, Shu H, Hu J, Lan X. [ 18F]F-ET-OTSSP167 Targets Maternal Embryo Leucine Zipper Kinase for PET Imaging of Triple-Negative Breast Cancer. Mol Pharm 2021; 18:3544-3552. [PMID: 34482695 DOI: 10.1021/acs.molpharmaceut.1c00454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Maternal embryo leucine zipper kinase (MELK) is a serine/threonine kinase and is highly expressed in triple-negative breast cancer (TNBC). This study aimed to develop a 18F-radiolabeled tracer based on the structure of a small-molecule MELK inhibitor OTSSP167 and evaluate its application for PET imaging of MELK expression in TNBC. OTSSP167 was modified with ethylene glycol to adjust its pharmacokinetics and was then radiolabeled with 18F to obtain [18F]F-ET-OTSSP167 at a labeling yield of 7.14 ± 2.19% and a molar activity of 16.23 ± 1.13 MBq/nmol. In vitro binding assays showed differentiated binding affinities of [18F]F-ET-OTSSP167 in different breast cancer cell lines, with high uptake in MDA-MB-231 (mild MELK expression) and low uptake in MCF-7 (negative MELK expression). PET imaging revealed that MDA-MB-231 tumors could be clearly delineated in vivo, while low tracer uptake was observed in MCF-7 tumors. These findings were confirmed by ex vivo biodistribution studies and were consistent with the immunohistochemistry and tissue staining results. Tracer accumulation in MDA-MB-231 tumors was significantly inhibited by excess amounts of OTSSP167, indicating high specificity of the tracer. In summary, [18F]F-ET-OTSSP167, an easily-prepared probe, can be used to visualize MELK positive tumors, demonstrating its promising clinical potential in selecting patients for MELK inhibitor therapy.
Collapse
Affiliation(s)
- Fan Hu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Chengpeng Gong
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Yongkang Gai
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Dawei Jiang
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Qingyao Liu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Sheng Wang
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Mengmeng Hu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Rundong Pi
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Hua Shu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Jia Hu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| | - Xiaoli Lan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan 430022, China
| |
Collapse
|
6
|
Zhang Z, Wang X, Ye J, Liu H, Fang J, Zhang M, Li Y, Huang J, Zhang D, Wang J, Zhang X. Development and Preclinical Evaluation of Radiolabeled Covalent G12C-Specific Inhibitors for Direct Imaging of the Oncogenic KRAS Mutant. Mol Pharm 2021; 18:3509-3518. [PMID: 34410132 DOI: 10.1021/acs.molpharmaceut.1c00426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although KRAS has been an important target for many cancers, direct inhibition of oncogenic RAS remains challenging. Until recently, covalent KRAS G12C-specific inhibitors have been developed and progressed to the clinics. Nevertheless, not all patients benefit from these covalent inhibitors. At present, identification of candidates for this treatment requires tissue biopsies and gene sequencing, which are invasive, time-consuming, and could be of insufficient quality and limited predictive value owing to tumor heterogeneity. The use of noninvasive molecular imaging techniques such as PET and SPECT for spying KRAS G12C mutation in tumors provide a promising strategy for circumventing these hurdles. In the present study, based on the covalent G12C-specific inhibitor ARS-1620, we sought to develop radiolabeled small molecules for direct imaging of the KRAS mutation status in tumors. [131I]I-ARS-1620 and [18F]F-ARS-1620 were successfully prepared with high radiochemical yield, radiochemical purity, and molar activity. In vitro and in vivo studies have demonstrated the affinity, specificity, and capacity of [131I]I-ARS-1620 for direct imaging of the oncogenic KRAS G12C mutant. This initial attempt allows us to directly screen the KRAS G12C mutant for the first time in vivo.
Collapse
Affiliation(s)
- Zhe Zhang
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Xiaobo Wang
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jiajun Ye
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Huanhuan Liu
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jianyang Fang
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Mingru Zhang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Yesen Li
- Department of Nuclear Medicine & Minnan PET Center, The First Affiliated Hospital of Xiamen University, Xiamen 361003, China
| | - Jinxiong Huang
- Department of Nuclear Medicine & Minnan PET Center, The First Affiliated Hospital of Xiamen University, Xiamen 361003, China
| | - Deliang Zhang
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jing Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Xianzhong Zhang
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| |
Collapse
|
7
|
Fang H, Cavaliere A, Li Z, Huang Y, Marquez-Nostra B. Preclinical Advances in Theranostics for the Different Molecular Subtypes of Breast Cancer. Front Pharmacol 2021; 12:627693. [PMID: 33986665 PMCID: PMC8111013 DOI: 10.3389/fphar.2021.627693] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/22/2021] [Indexed: 12/29/2022] Open
Abstract
Breast cancer is the most common cancer in women worldwide. The heterogeneity of breast cancer and drug resistance to therapies make the diagnosis and treatment difficult. Molecular imaging methods with positron emission tomography (PET) and single-photon emission tomography (SPECT) provide useful tools to diagnose, predict, and monitor the response of therapy, contributing to precision medicine for breast cancer patients. Recently, many efforts have been made to find new targets for breast cancer therapy to overcome resistance to standard of care treatments, giving rise to new therapeutic agents to offer more options for patients with breast cancer. The combination of diagnostic and therapeutic strategies forms the foundation of theranostics. Some of these theranostic agents exhibit high potential to be translated to clinic. In this review, we highlight the most recent advances in theranostics of the different molecular subtypes of breast cancer in preclinical studies.
Collapse
Affiliation(s)
- Hanyi Fang
- PET Center, Department of Radiology and Biomedical Imaging, School of Medicine, Yale University, New Haven, CT, United States.,Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
| | - Alessandra Cavaliere
- PET Center, Department of Radiology and Biomedical Imaging, School of Medicine, Yale University, New Haven, CT, United States
| | - Ziqi Li
- PET Center, Department of Radiology and Biomedical Imaging, School of Medicine, Yale University, New Haven, CT, United States.,Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yiyun Huang
- PET Center, Department of Radiology and Biomedical Imaging, School of Medicine, Yale University, New Haven, CT, United States
| | - Bernadette Marquez-Nostra
- PET Center, Department of Radiology and Biomedical Imaging, School of Medicine, Yale University, New Haven, CT, United States
| |
Collapse
|
8
|
A Radiobrominated Tyrosine Kinase Inhibitor for EGFR with L858R/T790M Mutations in Lung Carcinoma. Pharmaceuticals (Basel) 2021; 14:ph14030256. [PMID: 33809064 PMCID: PMC7998589 DOI: 10.3390/ph14030256] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 01/18/2023] Open
Abstract
Activating double mutations L858R/T790M in the epidermal growth factor receptor (EGFR) region are often observed as the cause of resistance to tyrosine kinase inhibitors (TKIs). Third-generation EGFR-TKIs, such as osimertinib and rociletinib (CO-1686), was developed to target such resistance mutations. The detection of activating L858R/T790M mutations is necessary to select sensitive patients for therapy. Hence, we aimed to develop novel radiobromine-labeled CO-1686 as a positron emission tomography (PET) imaging probe for detecting EGFR L858R/T790M mutations. Nonradioactive brominated-CO1686 (BrCO1686) was synthesized by the condensation of N-(3-[{2-chloro-5-(trifluoromethyl)pyrimidin-4-yl}amino]-5-bromophenyl) acrylamide with the corresponding substituted 1-(4-[4-amino-3-methoxyphenyl]piperazine-1-yl)ethan-1-one. The radiobrominated [77Br]BrCO1686 was prepared through bromodestannylation of the corresponding tributylstannylated precursor with [77Br]bromide and N-chlorosuccinimide. Although we aimed to provide a novel PET imaging probe, 77Br was used as an alternative radionuclide for 76Br. We fundamentally evaluated the potency of [77Br]BrCO1686 as a molecular probe for detecting EGFR L858R/T790M using human non-small-cell lung cancer (NSCLC) cell lines: H1975 (EGFR L858R/T790M), H3255 (EGFR L858R), and H441 (wild-type EGFR). The BrCO1686 showed high cytotoxicity toward H1975 (IC50 0.18 ± 0.06 µM) comparable to that of CO-1686 (IC50 0.14 ± 0.05 µM). In cell uptake experiments, the level of accumulation of [77Br]BrCO1686 in H1975 was significantly higher than those in H3255 and H441 upon 4 h of incubation. The radioactivity of [77Br]BrCO1686 (136.3% dose/mg protein) was significantly reduced to 56.9% dose/mg protein by the pretreatment with an excess CO-1686. These results indicate that the binding site of the radiotracers should be identical to that of CO-1686. The in vivo accumulation of radioactivity of [77Br]BrCO1686 in H1975 tumor (4.51 ± 0.17) was higher than that in H441 tumor (3.71 ± 0.13) 1 h postinjection. Our results suggested that [77Br]BrCO1686 has specificity toward NSCLC cells with double mutations EGFR L858R/T790M compared to those in EGFR L858R and wild-type EGFR. However, the in vivo accumulation of radioactivity in the targeted tumor needs to be optimized by structural modification.
Collapse
|
9
|
Wichmann CW, Goh YW, Parslow AC, Rigopoulos A, Guo N, Scott AM, Ackermann U, White JM. Synthesis and validation of [ 18F]mBPET-1, a fluorine-18 labelled mTOR inhibitor derivative based on a benzofuran backbone. EJNMMI Radiopharm Chem 2020; 5:3. [PMID: 31974638 PMCID: PMC6977806 DOI: 10.1186/s41181-020-0089-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/06/2020] [Indexed: 12/18/2022] Open
Abstract
Background Targeted therapy of HER2 positive breast cancer has led to clinical success in some cases with primary and secondary resistance being major obstacles. Due to the substantial involvement of mTOR kinase in cell growth and proliferation pathways it is now targeted in combination treatments to counteract HER2 targeted therapy resistance. However, the selection of receptive patient populations for a specific drug combination is crucial. This work aims to develop a molecular probe capable of identifying patients with tumour populations which are receptive to RAD001 combination therapy. Based on the structure of a mTOR inhibitor specific for mTORC1, we designed, synthesised and characterised a novel benzofuran based molecular probe which suits late stage fluorination via Click chemistry. Results Synthesis of the alkyne precursor 5 proceeded in 27.5% yield over 7 linear steps. Click derivatisation gave the non-radioactive standard in 25% yield. Radiosynthesis of [18F]1-((1-(2-Fluoroethyl)-1H-1,2,3-triazol-4-yl) methyl)-4-((5-methoxy-2-phenylbenzofuran-4-yl) methyl) piperazine ([18F]mBPET-1) proceeded over two steps which were automated on an iPhase FlexLab synthesis module. In the first step, 2-[18F]fluoroethylazide ([18F]6) was produced, purified by automated distillation in 60% non-decay-corrected yield and subjected to Click conditions with 5. Semi-preparative RP-HPLC purification and reformulation gave [18F]mBPET-1 in 40% ± 5% (n = 6) overall RCY with a process time of 90 min. Radiochemical purity was ≥99% at end of synthesis (EOS) and ≥ 98% after 4 h at room temperature. Molar activities ranged from typically 24.8 GBq/μmol (EOS) to a maximum of 78.6 GBq/μmol (EOS). Lipophilicity of [18F]mBPET-1 was determined at pH 7.4 (logD7.4 = 0.89). [18F]mBPET-1 showed high metabolic stability when incubated with mouse S9 liver fractions which resulted in a 0.8% drop in radiochemical purity after 3 h. Cell uptake assays showed 1.3–1.9-fold increased uptake of the [18F]mBPET-1 in RAD001 sensitive compared to insensitive cells across a panel of 4 breast cancer cell lines. Conclusion Molecular targeting of mTOR with [18F]mBPET-1 distinguishes mTOR inhibitor sensitive and insensitive cell lines. Future studies will explore the ability of [18F]mBPET-1 to predict response to mTOR inhibitor treatment in in vivo models.
Collapse
Affiliation(s)
- Christian W Wichmann
- The University of Melbourne, Parkville, VIC, 3010, Australia. .,Department of Molecular Imaging and Therapy, Austin Hospital, 145 Studley Road, Heidelberg, VIC, 3084, Australia. .,Olivia Newton-John Cancer Research Institute, 145 Studley Road, Heidelberg, VIC, 3084, Australia. .,School of Cancer Medicine, La Trobe University, Plenty Road & Kingsbury Drive, Bundoora, VIC, 3086, Australia.
| | - Yit Wooi Goh
- Department of Molecular Imaging and Therapy, Austin Hospital, 145 Studley Road, Heidelberg, VIC, 3084, Australia
| | - Adam C Parslow
- Olivia Newton-John Cancer Research Institute, 145 Studley Road, Heidelberg, VIC, 3084, Australia.,School of Cancer Medicine, La Trobe University, Plenty Road & Kingsbury Drive, Bundoora, VIC, 3086, Australia
| | - Angela Rigopoulos
- Olivia Newton-John Cancer Research Institute, 145 Studley Road, Heidelberg, VIC, 3084, Australia.,School of Cancer Medicine, La Trobe University, Plenty Road & Kingsbury Drive, Bundoora, VIC, 3086, Australia
| | - Nancy Guo
- Olivia Newton-John Cancer Research Institute, 145 Studley Road, Heidelberg, VIC, 3084, Australia
| | - Andrew M Scott
- The University of Melbourne, Parkville, VIC, 3010, Australia.,Department of Molecular Imaging and Therapy, Austin Hospital, 145 Studley Road, Heidelberg, VIC, 3084, Australia.,Olivia Newton-John Cancer Research Institute, 145 Studley Road, Heidelberg, VIC, 3084, Australia.,School of Cancer Medicine, La Trobe University, Plenty Road & Kingsbury Drive, Bundoora, VIC, 3086, Australia
| | - Uwe Ackermann
- The University of Melbourne, Parkville, VIC, 3010, Australia.,Department of Molecular Imaging and Therapy, Austin Hospital, 145 Studley Road, Heidelberg, VIC, 3084, Australia.,Olivia Newton-John Cancer Research Institute, 145 Studley Road, Heidelberg, VIC, 3084, Australia.,School of Cancer Medicine, La Trobe University, Plenty Road & Kingsbury Drive, Bundoora, VIC, 3086, Australia
| | | |
Collapse
|