| 1. |
- Abramenkovs, Andris, et al.
(författare)
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Ra-223 induces clustered DNA damage and inhibits cell survival in several prostate cancer cell lines
- 2022
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Ingår i: Translational Oncology. - : Elsevier. - 1944-7124 .- 1936-5233. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- The bone-seeking radiopharmaceutical Xofigo (Radium-223 dichloride) has demonstrated both extended sur-vival and palliative effects in treatment of bone metastases in prostate cancer. The alpha-particle emitter Ra-223, targets regions undergoing active bone remodeling and strongly binds to bone hydroxyapatite (HAp). However, the toxicity mechanism and properties of Ra-223 binding to hydroxyapatite are not fully understood. By exposing 2D and 3D (spheroid) prostate cancer cell models to free and HAp-bound Ra-223 we here studied cell toxicity, apoptosis and formation and repair of DNA double-strand breaks (DSBs). The rapid binding with a high affinity of Ra-223 to bone-like HAp structures was evident (KD= 19.2 x 10-18 M) and almost no dissociation was detected within 24 h. Importantly, there was no significant uptake of Ra-223 in cells. The Ra-223 alpha-particle decay produced track-like distributions of the DNA damage response proteins 53BP1 and gamma H2AX induced high amounts of clustered DSBs in prostate cancer cells and activated DSB repair through non-homologous end-joining (NHEJ). Ra-223 inhibited growth of prostate cancer cells, independent of cell type, and induced high levels of apoptosis. In summary, we suggest the high cell killing efficacy of the Ra-223 was attributed to the clustered DNA damaged sites induced by alpha-particles.
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| 2. |
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| 3. |
- Abramenkovs, Andris, et al.
(författare)
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The α-emitter Ra-223 induces clustered DNA damage and significantly reduces cell survival
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The bone-seeking radiopharmaceutical Xofigo (Radium-223 dichloride) has demonstrated both extended survival and palliative effects in treatment of bone metastases in patients with prostate cancer. The alpha-particle emitter Ra-223, administered as Ra-223 dichloride, targets regions undergoing active bone remodeling and strongly binds hydroxyapatite found in bone. However, the mechanisms mediating toxicity and properties of Ra-223 binding to hydroxyapatite are not fully understood. In the current study, we show that the alpha-particles originating from the Ra-223 decay chain produce a track-like distribution of the DNA damage response proteins 53BP1 and ɣH2AX and induce high amounts of clustered DNA double-strand breaks in prostate cancer cell nuclei. The Ra-223 treatment inhibited growth of prostate cancer cells, grown in 2D- and 3D- models in vitro, independent of prostate cancer cell type and androgen receptor variant 7 (ARv7) expression. The rapid binding with a high affinity of Ra-223 to bone structures was verified in an in silico assay (KD= 19.2 ± 6.5 e-18) and almost no dissociation was detected within 24 hours. Importantly, there was no significant uptake of Ra-223 in cells. Further, we demonstrate the importance of the local dose-distribution of this treatment; there was more than 100-fold increase in cell killing when Ra-223 was attached to the bone-like hydroxyapatite structure, compared to when the radioactivity was distributed in the cell growth media. However, independent of the exposure condition, the high cell killing efficacy of the Ra-223 was attributed to the clustered DNA damaged sites induced by the released α-particles.
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| 4. |
- Chandramohan, Arun, et al.
(författare)
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Design-rules for stapled peptides with in vivo activity and their application to Mdm2/X antagonists
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Although stapled α-helical peptides can address challenging targets, their advancement is impeded by poor understandings for making them cell permeable while avoiding off-target toxicities. By synthesizing >350 molecules, we present workflows for identifying stapled peptides against Mdm2(X) with in vivo activity and no off-target effects. Key insights include a clear correlation between lipophilicity and permeability, removal of positive charge to avoid off-target toxicities, judicious anionic residue placement to enhance solubility/behavior, optimization of C-terminal length/helicity to enhance potency, and optimization of staple type/number to avoid polypharmacology. Workflow application gives peptides with >292x improved cell proliferation potencies and no off-target cell proliferation effects ( > 3800x on-target index). Application of these ‘design rules’ to a distinct Mdm2(X) peptide series improves ( > 150x) cellular potencies and removes off-target toxicities. The outlined workflow should facilitate therapeutic impacts, especially for those targets such as Mdm2(X) that have hydrophobic interfaces and are targetable with a helical motif.
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| 5. |
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| 6. |
- Ingelshed, Katrine, et al.
(författare)
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MDM2/MDMX inhibition by Sulanemadlin synergizes with anti-Programmed Death 1 immunotherapy in wild-type p53 tumors
- 2024
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Ingår i: iScience. - : Elsevier. - 2589-0042. ; 27:6
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Tidskriftsartikel (refereegranskat)abstract
- Immunotherapy has revolutionized cancer treatment but its efficacy depends on a robust immune response in the tumor. Silencing of the tumor suppressor p53 is common in tumors and can affect the recruitment and activation of different immune cells, leading to immune evasion and poor therapy response. We found that the p53 activating stapled peptide MDM2/MDMX inhibitor Sulanemadlin (ALRN-6924) inhibited p53 wild-type cancer cell growth in vitro and in vivo. In mice carrying p53 wild-type CT26.WT tumors, monotherapy with the PD-1 inhibitor DX400 or Sulanemadlin delayed tumor doubling time by 50% and 37%, respectively, while combination therapy decreased tumor doubling time by 93% leading to an increased median survival time. Sulanemadlin treatment led to increased immunogenicity and combination treatment with PD-1 inhibition resulted in an increased tumor infiltration of lymphocytes. This combination treatment strategy could potentially turn partial responders into responders of immunotherapy, expanding the patient target group for PD-1-targeting immunotherapy.
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| 7. |
- Ingelshed, Katrine, et al.
(författare)
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The MDM2 Inhibitor Navtemadlin Arrests Mouse Melanoma Growth In Vivo and Potentiates Radiotherapy
- 2022
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Ingår i: Cancer Research Communications. - : American Association For Cancer Research (AACR). - 2767-9764. ; 2:9, s. 1075-1088
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Tidskriftsartikel (refereegranskat)abstract
- The tumor suppressor protein p53 is mutated in close to 50% of human tumors and is dysregulated in many others, for instance by silencing or loss of p14ARF. Under steady-state conditions, the two E3 ligases MDM2/MDM4 interact with and inhibit the transcriptional activity of p53. Inhibition of p53–MDM2/4 interaction to reactivate p53 in tumors with wild-type (WT) p53 has therefore been considered a therapeutic strategy. Moreover, studies indicate that p53 reactivation may synergize with radiation and increase tumor immunogenicity. In vivo studies of most MDM2 inhibitors have utilized immunodeficient xenograft mouse models, preventing detailed studies of action of these molecules on the immune response. The mouse melanoma cell line B16-F10 carries functional, WT p53 but does not express the MDM2 regulator p19ARF. In this study, we tested a p53-MDM2 protein–protein interaction inhibitor, the small molecule Navtemadlin, which is currently being tested in phase II clinical trials. Using mass spectrometry–based proteomics and imaging flow cytometry, we identified specific protein expression patterns following Navtemadlin treatment of B16-F10 melanoma cells compared with their p53 CRISPR-inactivated control cells. In vitro, Navtemadlin induced a significant, p53-dependent, growth arrest but little apoptosis in B16-F10 cells. When combined with radiotherapy, Navtemadlin showed synergistic effects and increased apoptosis. In vivo, Navtemadlin treatment significantly reduced the growth of B16-F10 melanoma cells implanted in C57Bl/6 mice. Our data highlight the utility of a syngeneic B16-F10 p53+/+ mouse melanoma model for assessing existing and novel p53-MDM2/MDM4 inhibitors and in identifying new combination therapies that can efficiently eliminate tumors in vivo.Significance:The MDM2 inhibitor Navtemadlin arrests mouse tumor growth and potentiates radiotherapy. Our results support a threshold model for apoptosis induction that requires a high, prolonged p53 signaling for cancer cells to become apoptotic.
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| 8. |
- Lundgren Mortensen, Anja Charlotte, et al.
(författare)
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Combination therapy of tyrosine kinase inhibitor sorafenib with the HSP90 inhibitor onalespib as a novel treatment regimen for thyroid cancer
- 2023
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Thyroid cancer is the most common endocrine malignancy, affecting nearly 600,000 new patients worldwide. Treatment with the BRAF inhibitor sorafenib partially prolongs progression-free survival in thyroid cancer patients, but fails to improve overall survival. This study examines enhancing sorafenib efficacy by combination therapy with the novel HSP90 inhibitor onalespib. In vitro efficacy of sorafenib and onalespib monotherapy as well as in combination was assessed in papillary (PTC) and anaplastic (ATC) thyroid cancer cells using cell viability and colony formation assays. Migration potential was studied in wound healing assays. The in vivo efficacy of sorafenib and onalespib therapy was evaluated in mice bearing BHT-101 xenografts. Sorafenib in combination with onalespib significantly inhibited PTC and ATC cell proliferation, decreased metabolic activity and cancer cell migration. In addition, the drug combination approach significantly inhibited tumor growth in the xenograft model and prolonged the median survival. Our results suggest that combination therapy with sorafenib and onalespib could be used as a new therapeutic approach in the treatment of thyroid cancer, significantly improving the results obtained with sorafenib as monotherapy. This approach has the potential to reduce treatment adaptation while at the same time providing therapeutic anti-cancer benefits such as reducing tumor growth and metastatic potential.
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| 9. |
- Lundgren Mortensen, Anja, et al.
(författare)
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The Stapled Peptide PM2 Stabilizes p53 Levels and Radiosensitizes Wild-Type p53 Cancer Cells
- 2019
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Ingår i: Frontiers in Oncology. - : Frontiers Media SA. - 2234-943X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The tumor suppressor p53 is a key mediator of cellular stress and DNA damage response cascades and is activated after exposure to ionizing radiation. Amplifying wild-type p53 expression by targeting negative regulators such as MDM2 in combination with external beam radiotherapy (EBRT) may result in increased therapeutic effects. The novel stapled peptide PM2 prevents MDM2 from suppressing wild-type p53, and is thus a promising agent for therapeutic combination with EBRT. Effects of PM2 and potential PM2-induced radiosensitivity were assessed in a panel of cancer cell lines using 2D cell viability assays. Western Blot and flow cytometric analyses were used to investigate the mechanisms behind the observed effects in samples treated with PM2 and EBRT. Finally, PM2-treatment combined with EBRT was evaluated in an in vitro 3D spheroid model. PM2-therapy decreased cell viability in wild-type p53, HPV-negative cell lines. Western Blotting and flow cytometry confirmed upregulation of p53, as well as initiation of p53-mediated apoptosis measured by increased cleaved caspase-3 and Noxa activity. Furthermore, 3D in vitro tumor spheroid experiments confirmed the superior effects of the combination, as the only treatment regime resulting in growth inhibition and complete spheroid disintegration. We conclude that PM2 induces antitumorigenic effects in wt p53 HPV-negative cancer cells and potentiates the effects of EBRT, ultimately resulting in tumor eradication in a 3D spheroid model. This strategy shows great potential as a new wt p53 specific tumor-targeting compound, and the combination of PM2 and EBRT could be a promising strategy to increase therapeutic effects and decrease adverse effects from radiotherapy.
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| 10. |
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| 11. |
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| 12. |
- Lundsten, Sara, et al.
(författare)
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The HSP90 inhibitor onalespib potentiates Lu-177-DOTATATE therapy in neuroendocrine tumor cells
- 2019
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Ingår i: International Journal of Oncology. - : SPANDIDOS PUBL LTD. - 1019-6439 .- 1791-2423. ; 55:6, s. 1287-1295
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Tidskriftsartikel (refereegranskat)abstract
- Lu-177-DOTATATE was recently approved for the treatment of somatostatin receptor (SSTR)-positive neuroen-docrine tumors (NETs). However, despite impressive response rates, complete responses are rare. Heat shock protein 90 (HSP90) inhibitors have been suggested as suitable therapeutic agents for NETs, as well as a potential radiosensitizers. Consequently, the aim of this study was to investigate whether the HSP90-inhibitor onalespib could reduce NET cell growth and act as a radiosensitizer when used in combination with Lu-177-DOTATATE. The NET cell lines BON, NCI-H727 and NCI-H460, were first characterized with regards to Lu-177-DOTATATE uptake and sensitivity to onalespib treatment in monolayer cell assays. The growth inhibitory effects of the monotherapies and combination treatments were then examined in three-dimensional multicellular tumor spheroids. Lastly, the molecular effects of the treatments were assessed. Lu-177-DOTATATE uptake was observed in the BON and NCI-H727 cells, while the NCI-H460 cells exhibited no detectable uptake. Accordingly, Lu-177-DOTATATE reduced the growth of BON and NCI-H727 spheroids, while no effect was observed in the NCI-H460 spheroids. Onalespib reduced cell viability and spheroid growth in all three cell lines. Furthermore, the combination of onalespib and Lu-177-DOTATATE exerted synergistic therapeutic effects on the BON and NCI-H727 spheroids. Western blot analysis of BON spheroids revealed the downregulation of epidermal growth factor receptor (EGFR) and the upregulation of gamma H2A histone family member X (gamma H2AX) following combined treatment with onalespib and Lu-177-DOTATATE. Moreover, flow cytometric analyses revealed a two-fold increase in caspase 3/7 activity in the combination group. In conclusion, the findings of this study demonstrate that onalespib exerts antitumorigenic effects on NET cells and may thus be a feasible treatment option for NETs. Furthermore, onalespib was able to synergistically potentiate Lu-177-DOTATATE treatment in a SSTR-specific manner. The radiosensitizing mechanisms of onalespib involved the downregulation of EGFR expression and the induction of apoptosis. Consequently, the combination of onalespib and Lu-177-DOTATATE may prove to be a promising strategy with which to improve therapeutic responses in patients with NETs. Further studies investigating this strategy in vivo regarding the therapeutic effects and potential toxicities are warranted to expand these promising findings.
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| 13. |
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| 14. |
- Lundsten, Sara, et al.
(författare)
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The radiosensitizer Onalespib increases complete remission in Lu-177-DOTATATE-treated mice bearing neuroendocrine tumor xenografts
- 2020
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : SPRINGER. - 1619-7070 .- 1619-7089. ; 47:4, s. 980-990
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Lu-177-DOTATATE targeting the somatostatin receptor (SSTR) is utilized for treatment of neuroendocrine tumors (NETs). Onalespib, a heat shock protein 90 (HSP90) inhibitor, has demonstrated radiosensitizing properties and may thus enhance the effect of Lu-177-DOTATATE. Consequently, the aim of this study was to assess the potential of Onalespib in combination with Lu-177-DOTATATE in vivo and to examine the toxicity profiles of the treatments.Methods: Lu-177-DOTATATE selectivity and distribution in NET xenografts were studied using biodistribution and autoradiography. Therapeutic effects of Onalespib in combination with Lu-177-DOTATATE were studied in NET xenografts. Histological analyses were used to assess molecular effects from treatment and to establish toxicity profiles.Results: Biodistribution and autoradiography confirmed the SSTR-selective tumor uptake of Lu-177-DOTATATE, which was unaffected by Onalespib treatment. Immunohistochemistry verified molecular responses to Onalespib therapy in the tumors. While Onalespib and Lu-177-DOTATATE monotherapies resulted in a 10% and 33% delay in tumor doubling time compared with control, the combination treatment resulted in a 73% delayed tumor doubling time. Moreover, combination treatment increased complete remissions threefold from Lu-177-DOTATATE monotherapy, resulting in 29% complete remissions. In addition, histological analyses demonstrated radiation-induced glomerular injury in the Lu-177-DOTATATE monotherapy group. The damage was decreased tenfold in the combination group, potentially due to Onalespib-induced HSP70 upregulation in the kidneys.Conclusion: Treatment with Onalespib potentiated Lu-177-DOTATATE therapy of NET xenografts with a favorable toxicity profile. Utilizing Onalespib's radiosensitizing properties with Lu-177-DOTATATE may lead to better therapeutic results in the future and may reduce unwanted side effects in dose-limiting organs.
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| 15. |
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| 16. |
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| 17. |
- Mortensen, Anja, et al.
(författare)
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Preclinical evaluation of a novel engineered recombinant human anti-CD44v6 antibody for potential use in radio-immunotherapy
- 2018
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Ingår i: International Journal of Oncology. - : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 52:6, s. 1875-1885
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Tidskriftsartikel (refereegranskat)abstract
- CD44v6 is overexpressed in a variety of cancers, rendering it a promising target for radio-immunotherapy (RIT). In this study, we have characterized a novel engineered recombinant monoclonal anti-CD44v6 antibody, AbN44v6, and assessed its potential for use in RIT using either Lu-177 or I-131 as therapeutic radionuclides. In vitro affinity and specificity assays characterized the binding of the antibody labeled with Lu-177, I-125 or I-131. The therapeutic effects of Lu-177-AbN44v6 and I-131-AbN44v6 were investigated using two in vitro 3D tumor models with different CD44v6 expression. Finally, the normal tissue biodistribution and dosimetry for Lu-177-AbN44v6 and I-125-AbN44v6/I-131-AbN44v6 were assessed in vivo using a mouse model. All AbN44v6 radioconjugates demonstrated CD44v6-specific binding in vitro. In the in vitro 3D tumor models, dose-dependent therapeutic effects were observed with both Lu-177-AbN44v6 and I-131-AbN44v6, with a greater significant therapeutic effect observed on the cells with a higher CD44v6 expression. Biodistribution experiments demonstrated a greater uptake of Lu-177-AbN44v6 in the liver, spleen and bone, compared to I-125-AbN44v6, whereas I-125-AbN44v6 demonstrated a longer circulation time. In dosimetric calculations, the critical organs for Lu-177-AbN44v6 were the liver and spleen, whereas the kidneys and red marrow were considered the critical organs for I-131-AbN44v6. The effective dose was in the order of 0.1 mSv/MBq for both labels. In conclusion, AbN44v6 bound specifically and with high affinity to CD44v6. Furthermore, in vitro RIT demonstrated growth inhibition in a CD44v6-specific activity-dependent manner for both radioconjugates, demonstrating that both Lu-177-AbN44v6 and I-131-AbN44v6 may be promising RIT candidates. Furthermore, biodistribution and dosimetric analysis supported the applicability of both conjugates for RIT. The CD44v6-specific therapeutic effects observed with radiolabeled AbN44v6 in the 3D tumor models in vitro, combined with the beneficial dosimetry in vivo, render AbN44v6 a potential candidate for RIT.
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| 18. |
- Mortensen, Anja, et al.
(författare)
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Utilizing CD44v6 and V600EBRAF-mutation for in vitro targeted combination therapy of thyroid carcinomas
- 2023
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Ingår i: Heliyon. - : Cell Press. - 2405-8440. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The aim of this study was to assess the feasibility of targeted therapy of thyroid carcinoma, first exploring potential targets BRAF, EGFR and CD44v6 in patient material through immunohistochemistry and mutation analysis.Materials and methods: A patient cohort (n = 22) consisting of seven papillary (PTC), eight anaplastic (ATC) and seven follicular (FTC) thyroid carcinomas were evaluated. Additionally, eight thyroid carcinoma cells lines were analyzed for CD44v6-expression and sensitivity to the multi-kinase inhibitor sorafenib (Nexavar (R)), which targets numerous serine/threonine and tyrosine kinases, including the Raf family kinases. Targeted therapy using 131I-AbN44v6, a novel anti-CD44v6 antibody, and/or sorafenib was evaluated in 3D multicellular tumor spheroids. RResults: Of the two cell surface proteins, EGFR and CD44v6, the latter was overexpressed in >80 % of samples, while EGFR-expression levels were moderate at best in only a few samples. BRAF mutations were more common in PTC patient samples than in ATC samples, while FTC samples did not harbor BRAF mutations. CD44v6-expression levels in the thyroid carcinoma cell lines were more heterogenous compared to patient samples, while BRAF mutational status was in line with the original tumor type. Monotherapy in 3D multicellular ATC tumor spheroids with either 131I-AbN44v6 or sorafenib resulted in delayed spheroid growth. The combination of 131I-AbN44v6 and sorafenib was the most potent and resulted in significantly impaired spheroid growth.Conclusion: This "proof of concept" targeted therapy study in the in vitro ATC 3D multicellular tumor spheroids indicated applicability of utilizing CD44v6 for molecular radiotherapy both as a monotherapy and in combination with sorafenib.
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| 19. |
- Spiegelberg, Diana, 1982-, et al.
(författare)
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CD44v6-Targeted Imaging of Head and Neck Squamous Cell Carcinoma : Antibody-Based Approaches
- 2017
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Ingår i: Contrast Media & Molecular Imaging. - : Hindawi Publishing Corporation. - 1555-4309 .- 1555-4317.
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Forskningsöversikt (refereegranskat)abstract
- Head and neck squamous cell carcinoma (HNSCC) is a common and severe cancer with low survival rate in advanced stages. Noninvasive imaging of prognostic and therapeutic biomarkers could provide valuable information for planning and monitoring of the different therapy options. Thus, there is amajor interest in development of new tracers towards cancer-specific molecular targets to improve diagnostic imaging and treatment. CD44v6, an oncogenic variant of the cell surface molecule CD44, is a promising molecular target since it exhibits a unique expression pattern in HNSCC and is associated with drug-and radio-resistance. In this review we summarize results from preclinical and clinical investigations of radiolabeled anti-CD44v6 antibody-based tracers: full-length antibodies, Fab, F(ab')(2) fragments, and scFvs with particular focus on the engineering of various antibody formats and choice of radiolabel for the use as molecular imaging agents in HNSCC. We conclude that the current evidence points to CD44v6 imaging being a promising approach for providing more specific and sensitive diagnostic tools, leading to customized treatment decisions and functional diagnosis. Improved imaging tools hold promise to enable more effective treatment for head and neck cancer patients.
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| 20. |
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| 21. |
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| 22. |
- Spiegelberg, Diana, 1982-, et al.
(författare)
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Higher Risk of Recurrence in Patients Treated for Head and Neck Cancer with Low BMI and Elevated Levels of C-Reactive Protein
- 2022
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 14:20
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary Head and neck cancer (HNC) treatment poses several challenges in clinical practice, and treatment side effects can be debilitating due to the close proximity of important anatomical structures. Cancer recurrence post-treatment presents some of the most challenging HNC management issues. This prospective study identifies high-risk groups for recurrence of head and neck cancer, based on commonly accessible clinical parameters. In this study with 272 HNC patients, elevated pre- and post-treatment CRP levels, low BMI and advanced stage at admission indicate higher risk for recurrence of disease. Using these parameters, a risk model is proposed which may be useful for estimating the probability of cancer recurrence and allow the identification of high and low-risk patients. This prospective study identifies high-risk groups for recurrence of head and neck cancer by BMI and circulating inflammatory response markers. Head and neck cancer patients from three Swedish hospitals were included (n = 272). Leukocyte and thrombocyte counts, CRP levels, and BMI were measured pre-treatment and post-treatment. Associations between the four factors and treatment failure (residual tumor, loco-regional failure, general failure/distant metastasis) were assessed using a Cox proportional hazards model adjusted for sex, age at the initial visit, smoking status, cancer stage, and hemoglobin count. CRP level was the only significant single variable, with an average increase in risk of recurrence of 74% (p = 0.018) for every doubling. The predictive power of a combined model using all variables was highest during the initial months after treatment, with AUC under the ROC curve 0.75 at the 0-3 month timepoints. Patients with elevated pre- and post-treatment CRP levels are at higher risk for recurrence of disease. Male patients with low post-treatment BMI, advanced stage, and high CRP at any time post treatment are at high risk for recurrence. The combined model may be useful for stratifying post-treatment patients into low and high-risk groups, to enable more detailed follow-up or additional treatment regimens.
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| 23. |
- Spiegelberg, Diana, 1982-
(författare)
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HSP90 inhibition in angiosarcoma
- 2017
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Ingår i: British Journal of Dermatology. - : WILEY. - 0007-0963 .- 1365-2133. ; 177:2, s. 343-344
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 24. |
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| 25. |
- Spiegelberg, Diana, 1982-, et al.
(författare)
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K-D determination from time-resolved experiments on live cells with LigandTracer and reconciliation with end-point flow cytometry measurements
- 2021
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Ingår i: European Biophysics Journal. - : Springer Nature. - 0175-7571 .- 1432-1017. ; 50:7, s. 979-991
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Tidskriftsartikel (refereegranskat)abstract
- Design of next-generation therapeutics comes with new challenges and emulates technology and methods to meet them. Characterizing the binding of either natural ligands or therapeutic proteins to cell-surface receptors, for which relevant recombinant versions may not exist, represents one of these challenges. Here we report the characterization of the interaction of five different antibody therapeutics (Trastuzumab, Rituximab, Panitumumab, Pertuzumab, and Cetuximab) with their cognate target receptors using LigandTracer. The method offers the advantage of being performed on live cells, alleviating the need for a recombinant source of the receptor. Furthermore, time-resolved measurements, in addition to allowing the determination of the affinity of the studied drug to its target, give access to the binding kinetics thereby providing a full characterization of the system. In this study, we also compared time-resolved LigandTracer data with end-point K-D determination from flow cytometry experiments and hypothesize that discrepancies between these two approaches, when they exist, generally come from flow cytometry titration curves being acquired prior to full equilibration of the system. Our data, however, show that knowledge of the kinetics of the interaction allows to reconcile the data obtained by flow cytometry and LigandTracer and demonstrate the complementarity of these two methods.
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| 26. |
- Spiegelberg, Diana, 1982-, et al.
(författare)
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The HSP90 inhibitor Onalespib exerts synergistic anti-cancer effects when combined with radiotherapy : an in vitro and in vivo approach
- 2020
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Oncogenic client-proteins of the chaperone Heat shock protein 90 (HSP90) insure unlimited tumor growth and are involved in resistance to chemo- and radiotherapy. The HSP90 inhibitor Onalespib initiates the degradation of oncoproteins, and might also act as a radiosensitizer. The aim of this study was therefore to evaluate the efficacy of Onalespib in combination with external beam radiotherapy in an in vitro and in vivo approach. Onalespib downregulated client proteins, lead to increased apoptosis and caused DNA-double-strands. Monotherapy and combination with radiotherapy reduced colony formation, proliferation and migration assessed in radiosensitive HCT116 and radioresistant A431 cells. In vivo, a minimal treatment regimen for 3 consecutive days of Onalespib (3 x 10 mg/kg) doubled survival, whereas Onalespib with radiotherapy (3 x 2 Gy) caused a substantial delay in tumor growth and prolonged the survival by a factor of 3 compared to the HCT116 xenografted control group. Our results demonstrate that Onalespib exerts synergistic anti-cancer effects when combined with radiotherapy, most prominent in the radiosensitive cell models. We speculate that the depletion and downregulation of client proteins involved in signalling, migration and DNA repair mechanisms is the cause. Thus, individually, or in combination with radiotherapy Onalespib inhibits tumor growth and has the potential to improve radiotherapy outcomes, prolonging the overall survival of cancer patients.
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| 27. |
- Spiegelberg, Diana, 1982-, et al.
(författare)
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The MDM2/MDMX-p53 Antagonist PM2 Radiosensitizes Wild-Type p53 Tumors
- 2018
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Ingår i: Cancer Research. - : AMER ASSOC CANCER RESEARCH. - 0008-5472 .- 1538-7445. ; 78:17, s. 5084-5093
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Tidskriftsartikel (refereegranskat)abstract
- Radiotherapy amplifies p53 expression in cancer cells with wild-type (wt) p53. Blocking the negative regulators MDM2 and MDMX stabilizes p53 and may therefore potentiate radiotherapy outcomes. In this study, we investigate the efficacy of the novel anti-MDM2/X stapled peptide PM2 alone and in combination with externalgamma radiation in vitro and in vivo. PM2 therapy combined with radiotherapy elicited synergistic therapeutic effects compared with monotherapy in cells with wt p53 in both in vitro and in vivo assays, whereas these effects did not manifest in p53(-/-) cells. Biodistribution and autoradiography of 125I-PM2 revealed high and retained uptake homogenously distributed throughout the tumor. In mice carrying wt p53 tumors, PM2 combined with radiother-apy significantly prolonged the median survival by 50%, whereas effects of PM2 therapy on mutant and p53(-/-) tumors were negligible. PM2-dependent stabilization of p53 was confirmed with ex vivo immunohistochemistry. These data demonstrate the potential of the stapled peptide PM2 as a radiotherapy potentiator in vivo and suggest that clinical application of PM2 with radiotherapy in wt p53 cancers might improve tumor control.Significance: These findings contribute advances to cancer radiotherapy by using novel p53-reactivating stapled peptides as radiosensitizers in wild-type p53 cancers.
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| 28. |
- Spiegelberg, Diana, 1982-, et al.
(författare)
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The Novel Anti-cMet Antibody seeMet 12 Potentiates Sorafenib Therapy and Radiotherapy in a Colorectal Cancer Model
- 2020
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Ingår i: Frontiers in Oncology. - : Frontiers Media SA. - 2234-943X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Rational: cMet is abnormally regulated in gastrointestinal cancer, and is associated with increased invasiveness of the disease and poor overall survival. There are indications that targeted therapy against cMet, alone or in combination with additional cancer therapies, can help improve treatment outcome. Thus, in the present study we investigated the therapeutic efficacy of a novel cMet-targeting antibody therapy in gastrointestinal cancer models, and assessed potential augmenting effects in combination with tyrosine kinase inhibitor (TKI) targeted therapy or radiotherapy.Methods: Three different cMet-targeting antibodies were first characterized with respect to antigen binding and effects on cell viability in vitro. The best performing candidate seeMet 12 was then further assessed for effects on colorectal cancer cell growth, proliferation and migration. Combinations with the TKI-inhibitor sorafenib or external beam radiotherapy were then evaluated for potential additive or synergistic effects in vitro using monolayer- and multicellular tumor spheroid assays. Finally, the combination of seeMet 12 and radiotherapy was evaluated in vivo in a proof-of-concept colorectal cancer xenograft study.Results: Dose-dependent therapeutic effects were demonstrated for all three cMet-targeting antibodies. Monotherapy using seeMet 12 resulted in impaired cellular migration/proliferation and reduced tumor spheroid growth. Moreover, seeMet 12 was able to potentiate therapeutic effects in vitro for both sorafenib and radiotherapy treatments. Finally, the in vivo therapy study demonstrated promising results, where a combination of seeMet 12 and fractionated radiotherapy increased median survival by 79% compared to radiotherapy alone, and tripled maximum survival.Conclusion: The novel anti-cMet antibody seeMet 12 demonstrated therapeutic effects in cMet positive gastrointestinal cancer cells in vitro. Moreover, the addition of seeMet 12 augmented the effects of sorafenib and radiotherapy. An in vivo proof-of-concept study of seeMet 12 and radiotherapy further validated the results. Thus, cMet-targeted therapy should be further explored as a promising approach to increase therapeutic effects, circumvent treatment resistance, and reduce side effects.
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| 29. |
- Spiegelberg, Diana, 1982-, et al.
(författare)
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The novel HSP90 inhibitor AT13387 potentiates radiation effects in squamous cell carcinoma and adenocarcinoma cells
- 2015
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 6:34, s. 35652-35666
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Tidskriftsartikel (refereegranskat)abstract
- Overexpression of heat shock protein 90 (HSP90) is associated with increased tumor cell survival and radioresistance. In this study we explored the efficacy of the novel HSP90 inhibitor AT13387 and examined its radiosensitizing effects in combination with gamma-radiation in 2D and 3D structures as well as mice-xenografts. AT13387 induced effective cytotoxic activity and radiosensitized cancer cells in monolayer and tumor spheroid models, where low drug doses triggered significant synergistic effects on cell survival together with radiation. Furthermore, AT13387 treatment resulted in G2/M-phase arrest and significantly reduced the migration capacity. The expression of selected client proteins involved in DNA repair, cell-signaling and cell growth was downregulated in vitro, though the expression of most investigated proteins recurred after 8-24 h. These results were confirmed in vivo where AT13387 treated tumors displayed effective downregulation of HSP90 and its oncogenic client proteins. In conclusion, our results demonstrate that AT13387 is a potent new cancer drug and effective radiosensitizer in vitro with an excellent in vivo efficacy. AT13387 treatment has the potential to improve external beam therapy and radionuclide therapy outcomes and restore treatment efficacy in cancers that are resistant to initial therapeutic regimes.
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| 30. |
- Spiegelberg, Diana, 1982-
(författare)
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Towards Personalized Cancer Therapy : New Diagnostic Biomarkers and Radiosensitization Strategies
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on the evaluation of biomarkers for radio-immunodiagnostics and radio-immunotherapy and on radiosensitization strategies after HSP90 inhibition, as a step towards more personalized cancer medicine. There is a need to develop new tracers that target cancer-specific biomarkers to improve diagnostic imaging, as well as to combine treatment strategies to potentiate synergistic effects. Special focus has been on the cell surface molecule CD44 and its oncogenic variants, which were found to exhibit unique expression patterns in head and neck squamous cell carcinoma (HNSCC). The variant CD44v6 seems to be a promising target, because it is overexpressed in this cancer type and is associated with radioresistance. Two new radioconjugates that target CD44v6, namely, the Fab fragment AbD15179 and the bivalent fragment AbD19384, were investigated with regard to specificity, biodistribution and imaging performance. Both conjugates were able to efficiently target CD44v6-positive tumors in vitro and in vivo. PET imaging of CD44v6 with 124I-AbD19384 revealed many advantages compared with the clinical standard 18F-FDG. Furthermore, the efficacy of the novel HSP90 inhibitor AT13387 and its potential use in combination with radiation treatment were evaluated. AT13387 proved to be a potent new cancer drug with favorable pharmacokinetics. Synergistic combination effects at clinically relevant drug and radiation doses are promising for both radiation dose reduction and minimization of side effects, or for an improved therapeutic response. The AT13387 investigation indicated that CD44v6 is not dependent on the molecular chaperone HSP90, and therefore, radio-immunotargeting of CD44v6 in combination with the HSP90 inhibitor AT13387 might potentiate treatment outcomes. However, EGFR expression levels did correlate with HSP90 inhibition, and therefore, molecular imaging of EGFR-positive tumors may be used to assess the treatment response to HSP90 inhibitors.In conclusion, these results demonstrate how tumor targeting with radiolabeled vectors and chemotherapeutic compounds can provide more specific and sensitive diagnostic tools and treatment options, which can lead to customized treatment decisions and a functional diagnosis that provides more precise and safer drug prescribing, as well as a more effective treatment for each patient.
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| 31. |
- Yu Koh, Xin, et al.
(författare)
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Conformation specific antagonistic high affinity antibodies to the RON receptor kinase for imaging and therapy
- 2022
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The RON receptor tyrosine kinase is an exceptionally interesting target in oncology and immunology. It is not only overexpressed in a wide variety of tumors but also has been shown to be expressed on myeloid cells associated with tumor infiltration, where it serves to dampen tumour immune responses and reduce the efficacy of anti-CTLA4 therapy. Potent and selective inhibitory antibodies to RON might therefore both inhibit tumor cell growth and stimulate immune rejection of tumors. We derived cloned and sequenced a new panel of exceptionally avid anti-RON antibodies with picomolar binding affinities that inhibit MSP-induced RON signaling and show remarkable potency in antibody dependent cellular cytotoxicity. Antibody specificity was validated by cloning the antibody genes and creating recombinant antibodies and by the use of RON knock out cell lines. When radiolabeled with 89-Zirconium, the new antibodies 3F8 and 10G1 allow effective immuno-positron emission tomography (immunoPET) imaging of RON-expressing tumors and recognize universally exposed RON epitopes at the cell surface. The 10G1 was further developed into a novel bispecific T cell engager with a 15 pM EC50 in cytotoxic T cell killing assays.
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