| 1. |
- Abou, Diane S., et al.
(författare)
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Improved 223Ra Therapy with Combination Epithelial Sodium Channel Blockade
- 2021
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 2159-662X. ; 62:12, s. 1751-1758
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Tidskriftsartikel (refereegranskat)abstract
- [223Ra]RaCl2 is the first approved a-particle-emitting therapy and is indicated for treatment of bonemetastatic castration-resistant prostate cancer. Approximately half the dose is absorbed into the gastrointestinal tract within minutes of administration, limiting disease-site uptake and contributing to toxicity. Here,we investigated the role of enteric ion channels and their modulation for improved therapeutic efficacy and reduced side effects. Methods: Using primary human duodenal organoids (enteroids) asin vitromodelsof the functionalgastrointestinal epithelium, we found that amiloride (epithelial sodium ion channel blocker) and NS-1619 (K+ channel activator) presented significant effects in 223Ramembranal transport.Radioactivedrugdistributionwas evaluated for lead combinations in vivo and in osteosarcoma and prostate cancermodels.Results:Amiloride shifted 223Ra uptake in vivo fromthe gut and nearly doubled the uptake at sites of bone remodeling. Bone tumor growth inhibition with the combination as measured by bioluminescent imaging and radiographywas significantly greater than that with single agents alone, and the combination resulted in noweight loss.Conclusion: This combination of approved agentsmay readily be implemented as a clinical approach to improve the outcomes of bonemetastatic cancer patients with the benefit of ameliorated tolerability. COPYRIGHT
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| 2. |
- Abou, Diane S., et al.
(författare)
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Preclinical Single Photon Emission Computed Tomography of Alpha Particle-Emitting Radium-223
- 2020
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Ingår i: Cancer Biotherapy and Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1084-9785 .- 1557-8852. ; 35:7, s. 520-529
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Dose optimization and pharmacokinetic evaluation of α-particle emitting radium-223 dichloride (223RaCl2) by planar γ-camera or single photon emission computed tomography (SPECT) imaging are hampered by the low photon abundance and injected activities. In this study, we demonstrate SPECT of 223Ra using phantoms and small animal in vivo models. Methods: Line phantoms and mice bearing 223Ra were imaged using a dedicated small animal SPECT by detecting the low-energy photon emissions from 223Ra. Localization of the therapeutic agent was verified by whole-body and whole-limb autoradiography and its radiobiological effect confirmed by immunofluorescence. Results: A state-of-the-art commercial small animal SPECT system equipped with a highly sensitive collimator enables collection of sufficient counts for three-dimensional reconstruction at reasonable administered activities and acquisition times. Line sources of 223Ra in both air and in a water scattering phantom gave a line spread function with a full-width-at-half-maximum of 1.45 mm. Early and late-phase imaging of the pharmacokinetics of the radiopharmaceutical were captured. Uptake at sites of active bone remodeling was correlated with DNA damage from the α particle emissions. Conclusions: This work demonstrates the capability to noninvasively define the distribution of 223RaCl2, a recently approved α-particle-emitting radionuclide. This approach allows quantitative assessment of 223Ra distribution and may assist radiation-dose optimization strategies to improve therapeutic response and ultimately to enable personalized treatment planning.
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| 3. |
- Abou, Diane S, et al.
(författare)
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Whole-Body and Microenvironmental Localization of Radium-223 in Naïve and Mouse Models of Prostate Cancer Metastasis.
- 2016
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 1460-2105 .- 0027-8874. ; 108:5
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Tidskriftsartikel (refereegranskat)abstract
- Bone-metastatic, castration-resistant prostate cancer (bmCRPC) represents a lethal stage of the most common noncutaneous cancer in men. The recent introduction of Radium-223 dichloride, a bone-seeking alpha particle (α)-emitting radiopharmaceutical, demonstrates statistically significant survival benefit and palliative effect for bmCRPC patients. Clinical results have established safety and efficacy, yet questions remain regarding pharmacodynamics and dosing for optimized patient benefit.
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| 4. |
- Benabdallah, Nadia, et al.
(författare)
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Beyond Average : a-Particle Distribution and Dose Heterogeneity in Bone Metastatic Prostate Cancer
- 2024
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Ingår i: Journal of Nuclear Medicine. - 0161-5505. ; 65:2, s. 245-251
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Tidskriftsartikel (refereegranskat)abstract
- a-particle emitters are emerging as a potent modality for disseminated cancer therapy because of their high linear energy transfer and localized absorbed dose profile. Despite great interest and pharmaceutical development, there is scant information on the distribution of these agents at the scale of the a-particle pathlength. We sought to determine the distribution of clinically approved [223Ra]RaCl2 in bone metastatic castration-resistant prostate cancer at this resolution, for the first time to our knowledge, to inform activity distribution and dose at the near-cell scale. Methods: Biopsy specimens and blood were collected from 7 patients 24 h after administration. 223Ra activity in each sample was recorded, and the microstructure of biopsy specimens was analyzed by micro-CT. Quantitative autoradiography and histopathology were segmented and registered with an automated procedure. Activity distributions by tissue compartment and dosimetry calculations based on the MIRD formalism were performed. Results: We revealed the activity distribution differences across and within patient samples at the macro- and microscopic scales. Microdistribution analysis confirmed localized high-activity regions in a background of low-activity tissue. We evaluated heterogeneous a-particle emission distribution concentrated at bone–tissue interfaces and calculated spatially nonuniform absorbed-dose profiles. Conclusion: Primary patient data of radiopharmaceutical therapy distribution at the small scale revealed that 223Ra uptake is nonuniform. Dose estimates present both opportunities and challenges to enhance patient outcomes and are a first step toward personalized treatment approaches and improved understanding of a-particle radiopharmaceutical therapies.
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| 5. |
- McDevitt, Michael R., et al.
(författare)
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Feed-forward alpha particle radiotherapy ablates androgen receptor-addicted prostate cancer
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Human kallikrein peptidase 2 (hK2) is a prostate specific enzyme whose expression is governed by the androgen receptor (AR). AR is the central oncogenic driver of prostate cancer (PCa) and is also a key regulator of DNA repair in cancer. We report an innovative therapeutic strategy that exploits the hormone-DNA repair circuit to enable molecularly-specific alpha particle irradiation of PCa. Alpha-particle irradiation of PCa is prompted by molecularly specific-targeting and internalization of the humanized monoclonal antibody hu11B6 targeting hK2 and further accelerated by inherent DNA-repair that up-regulate hK2 (KLK2) expression in vivo. hu11B6 demonstrates exquisite targeting specificity for KLK2. A single administration of actinium-225 labeled hu11B6 eradicates disease and significantly prolongs survival in animal models. DNA damage arising from alpha particle irradiation induces AR and subsequently KLK2, generating a unique feed-forward mechanism, which increases binding of hu11B6. Imaging data in nonhuman primates support the possibility of utilizing hu11B6 in man.
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| 6. |
- Storey, Claire M, et al.
(författare)
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Quantitative In Vivo Imaging of the Androgen Receptor Axis Reveals Degree of Prostate Cancer Radiotherapy Response
- 2023
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Ingår i: Molecular cancer research : MCR. - 1557-3125. ; 21:4, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Non-invasive biomarkers for androgen receptor (AR) pathway activation are urgently needed to better monitor patient response to prostate cancer (PCa) therapies. AR is a critical driver and mediator of resistance of PCa but currently available non-invasive PCa biomarkers to monitor AR activity are discordant with downstream AR pathway activity. External beam radiotherapy (EBRT) remains a common treatment for all stages of PCa, and DNA damage induced by EBRT upregulates AR pathway activity to promote therapeutic resistance. [89Zr]11B6-PET is a novel modality targeting prostate-specific protein human kallikrein 2 (hK2), which is a surrogate biomarker for AR activity. Here, we studied if [&sup89;Zr]11B6-PET can accurately assess EBRT-induced AR activity. Genetic and human PCa mouse models received EBRT (2-50 Gy) and treatment response was monitored by [89Zr]11B6-PET/CT. Radiotracer uptake and expression of AR and AR target genes was quantified in resected tissue. EBRT increased AR pathway activity and [&sup89;Zr]11B6 uptake in LNCaP-AR and 22RV1 tumors. EBRT increased prostate-specific [&sup89;Zr]11B6 uptake in PCa-bearing mice (Hi-Myc x Pb_KLK2) with no significant changes in uptake in healthy (Pb_KLK2) mice, and this correlated with hK2 protein levels. Implications: hK2 expression in PCa tissue is a proxy of EBRT-induced AR activity that can non-invasively be detected using [&sup89;Zr]11B6-PET; further clinical evaluation of hK2-PET for monitoring response and development of resistance to EBRT in real time is warranted.
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| 7. |
- Thorek, Daniel L.J., et al.
(författare)
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Harnessing androgen receptor pathway activation for targeted alpha particle radioimmunotherapy of breast cancer
- 2019
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Ingår i: Clinical Cancer Research. - 1078-0432. ; 25:2, s. 881-891
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The impact of androgen receptor (AR) activity Results: D-Norgestrel and DHT activated the AR pathway, in breast cancer biology is unclear. We characterized and while 17b-Estradiol did not. Competitive binding for AR tested a novel therapy to an AR-governed target in breast protein showed similar affinity between DHT and D-Norges-cancer. trel, indicating direct AR–ligand interaction. In vivo production Experimental Design: We evaluated the expression of of hK2 was sufficient to achieve site-specific delivery of ther-prototypical AR gene products human kallikrein 2 (hK2) apeutic radionuclide to tumor tissue at >20-fold over back- and PSA in breast cancer models. We screened 13 well-ground muscle uptake; effecting long-term local tumor characterized breast cancer cell lines for hK2 and PSA control. production upon in vitro hormone stimulation by testoster-Conclusions: [225Ac]hu11B6 targeted radiotherapy one [dihydrotestosterone (DHT)]. AR-positive lines were was potentiated by DHT and by D-Norgestrel in murine further evaluated by exposure to estrogen (17b-Estradiol) xenograft models of breast cancer. AR activity in and the synthetic progestin D-Norgestrel. We then evaluated breast cancer correlates with kallikrein-related peptidase-2 an anti-hK2–targeted radiotherapy platform (hu11B6), and can be activated by D-Norgestrel, a common con-labeled with alpha (a)-particle emitting Actinium-225, to traceptive, and AR induction can be harnessed for hK2-specifically treat AR-expressing breast cancer xenografts targeted breast cancer a-emitter radiotherapy. under hormone stimulation.
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| 8. |
- Thorek, Daniel L J, et al.
(författare)
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Internalization of secreted antigen-targeted antibodies by the neonatal Fc receptor for precision imaging of the androgen receptor axis
- 2016
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Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 8:367
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Tidskriftsartikel (refereegranskat)abstract
- Targeting the androgen receptor (AR) pathway prolongs survival in patients with prostate cancer, but resistance rapidly develops. Understanding this resistance is confounded by a lack of noninvasive means to assess AR activity in vivo. We report intracellular accumulation of a secreted antigen-targeted antibody (SATA) that can be used to characterize disease, guide therapy, and monitor response. AR-regulated human kallikrein-related peptidase 2 (free hK2) is a prostate tissue-specific antigen produced in prostate cancer and androgen-stimulated breast cancer cells. Fluorescent and radio conjugates of 11B6, an antibody targeting free hK2, are internalized and noninvasively report AR pathway activity in metastatic and genetically engineered models of cancer development and treatment. Uptake is mediated by a mechanism involving the neonatal Fc receptor. Humanized 11B6, which has undergone toxicological tests in nonhuman primates, has the potential to improve patient management in these cancers. Furthermore, cellspecific SATA uptake may have a broader use for molecularly guided diagnosis and therapy in other cancers.
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| 9. |
- Thorek, Daniel L J, et al.
(författare)
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Non-invasive mapping of deep-tissue lymph nodes in live animals using a multimodal PET/MRI nanoparticle.
- 2014
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5:Jan 20
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Tidskriftsartikel (refereegranskat)abstract
- The invasion status of tumour-draining lymph nodes (LNs) is a critical indicator of cancer stage and is important for treatment planning. Clinicians currently use planar scintigraphy and single-photon emission computed tomography (SPECT) with (99m)Tc-radiocolloid to guide biopsy and resection of LNs. However, emerging multimodality approaches such as positron emission tomography combined with magnetic resonance imaging (PET/MRI) detect sites of disease with higher sensitivity and accuracy. Here we present a multimodal nanoparticle, (89)Zr-ferumoxytol, for the enhanced detection of LNs with PET/MRI. For genuine translational potential, we leverage a clinical iron oxide formulation, altered with minimal modification for radiolabelling. Axillary drainage in naive mice and from healthy and tumour-bearing prostates was investigated. We demonstrate that (89)Zr-ferumoxytol can be used for high-resolution tomographic studies of lymphatic drainage in preclinical disease models. This nanoparticle platform has significant translational potential to improve preoperative planning for nodal resection and tumour staging.
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