| 1. |
- Bonagas, Nadilly, et al.
(författare)
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Pharmacological targeting of MTHFD2 suppresses acute myeloid leukemia by inducing thymidine depletion and replication stress
- 2022
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Ingår i: NATURE CANCER. - : Springer Science and Business Media LLC. - 2662-1347. ; 3:2, s. 156-
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Tidskriftsartikel (refereegranskat)abstract
- The folate metabolism enzyme MTHFD2 (methylenetetrahydrofolate dehydrogenase/cyclohydrolase) is consistently overexpressed in cancer but its roles are not fully characterized, and current candidate inhibitors have limited potency for clinical development. In the present study, we demonstrate a role for MTHFD2 in DNA replication and genomic stability in cancer cells, and perform a drug screen to identify potent and selective nanomolar MTHFD2 inhibitors; protein cocrystal structures demonstrated binding to the active site of MTHFD2 and target engagement. MTHFD2 inhibitors reduced replication fork speed and induced replication stress followed by S-phase arrest and apoptosis of acute myeloid leukemia cells in vitro and in vivo, with a therapeutic window spanning four orders of magnitude compared with nontumorigenic cells. Mechanistically, MTHFD2 inhibitors prevented thymidine production leading to misincorporation of uracil into DNA and replication stress. Overall, these results demonstrate a functional link between MTHFD2-dependent cancer metabolism and replication stress that can be exploited therapeutically with this new class of inhibitors. Helleday and colleagues describe a nanomolar MTHFD2 inhibitor that causes replication stress and DNA damage accumulation in cancer cells via thymidine depletion, demonstrating a potential therapeutic strategy in AML tumors in vivo.
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| 2. |
- Almqvist, Helena, et al.
(författare)
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CETSA screening identifies known and novel thymidylate synthase inhibitors and slow intracellular activation of 5-fluorouracil
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Target engagement is a critical factor for therapeutic efficacy. Assessment of compound binding to native target proteins in live cells is therefore highly desirable in all stages of drug discovery. We report here the first compound library screen based on biophysical measurements of intracellular target binding, exemplified by human thymidylate synthase (TS). The screen selected accurately for all the tested known drugs acting on TS. We also identified TS inhibitors with novel chemistry and marketed drugs that were not previously known to target TS, including the DNA methyltransferase inhibitor decitabine. By following the cellular uptake and enzymatic conversion of known drugs we correlated the appearance of active metabolites over time with intracellular target engagement. These data distinguished a much slower activation of 5-fluorouracil when compared with nucleoside-based drugs. The approach establishes efficient means to associate drug uptake and activation with target binding during drug discovery.
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| 3. |
- Back, Tom, et al.
(författare)
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Glomerular Filtration Rate After Alpha-Radioimmunotherapy with At-211-MX35-F(ab ')(2): A Long-Term Study of Renal Function in Nude Mice
- 2009
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Ingår i: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 24:6, s. 649-658
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Tidskriftsartikel (refereegranskat)abstract
- Besides bone marrow, the kidneys are often dose-limiting organs in internal radiotherapy. The effects of high-linear energy transfer (LET) radiation on the kidneys after alpha-radioimmunotherapy (alpha-RIT) with the alpha-particle emitter, At-211, were studied in nude mice by serial measurements of the glomerular filtration rate (GFR). The renal toxicity was evaluated at levels close to the dose limit for the bone marrow and well within the range for therapeutic efficacy on tumors. Astatinated MX35-F(ab ')(2) monoclonal antibodies were administered intravenously to nude mice. Both non-tumor-bearing animals and animals bearing subcutaneous xenografts of the human ovarian cancer cell line, OVCAR-3, were used. The animals received approximately 0.4, 0.8, or 1.2MBq in one, two, or three fractions. The mean absorbed doses to the kidneys ranged from 1.5 to 15 Gy. The renal function was studied by serial GFR measurements, using plasma clearance of Cr-51-EDTA, up to 67 weeks after the first astatine injection. A dose-dependent effect on GFR was found and at the time interval 8-30 weeks after the first administration of astatine, the absorbed doses causing a 50% decrease in GFR were 16.4 +/- 3.3 and 14.0 +/- 4.1 Gy (mean +/- SEM), tumor-and non-tumor-bearing animals, respectively. The reduction in GFR progressed with time, and at the later time interval, (31-67 weeks) the corresponding absorbed doses were 7.5 +/- 2.4 and 11.3 +/- 2.3 Gy, respectively, suggesting that the effects of radiation on the kidneys were manifested late. Examination of the kidney sections showed histologic changes that were overall subdued. Following a-RIT with 211 At-MX35-F(ab')(2) at levels close to the dose limit of severe myelotoxicity, the effects found on renal function were relatively small, with only minor to moderate reductions in GFR. These results suggest that a mean absorbed dose to the kidneys of approximately 10Gy is acceptable, and that the kidneys would not be the primary dose-limiting organ in systemic a-RIT when using At-211-MX35-F(ab')(2).
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| 4. |
- Buvall, Lisa, 1976, et al.
(författare)
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Orellanine specifically targets renal clear cell carcinoma
- 2017
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 8:53, s. 91085-91098
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Tidskriftsartikel (refereegranskat)abstract
- Renal cell carcinoma (RCC), arising from the proximal tubule in the kidney, accounts for approximately 85% of kidney cancers and causes over 140,000 annual deaths worldwide. In the last decade, several new therapies have been identified for treatment of metastatic RCC. Although these therapies increase survival time compared to standard care, none of them has curative properties. The nephrotoxin orellanine specifically targets proximal tubular epithelial cells, leaving other organs unaffected. We therefore hypothesized that the selective toxicity of orellanine extends to clear cell RCC (ccRCC) cells since they emanate from proximal tubular cells. Orellanine would thus target both primary and metastatic ccRCC in vitro and in vivo. We found that orellanine induces dose-dependent cell death in proximal tubular cells and in all ccRCC cells tested, both primary and cell lines, with no toxicity detected in control cells. The toxic action of orellanine involve decreased protein synthesis, disrupted cell metabolism and induction of apoptosis. In nude rats carrying human ccRCC xenografts, brief orellanine treatment eliminated more than 90% of viable tumor mass compared to control rats. This identifies orellanine as a potential treatment concept for ccRCC patients on dialysis, due to its unique selective toxicity towards ccRCC.
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| 5. |
- Bäck, Tom, 1964, et al.
(författare)
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Glomerular filtration rate after alpha-radioimmunotherapy with 211At-MX35-F(ab')2: a long-term study of renal function in nude mice.
- 2009
-
Ingår i: Cancer biotherapy & radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 24:6, s. 649-58
-
Tidskriftsartikel (refereegranskat)abstract
- Besides bone marrow, the kidneys are often dose-limiting organs in internal radiotherapy. The effects of high-linear energy transfer (LET) radiation on the kidneys after alpha-radioimmunotherapy (alpha-RIT) with the alpha-particle emitter, (211)At, were studied in nude mice by serial measurements of the glomerular filtration rate (GFR). The renal toxicity was evaluated at levels close to the dose limit for the bone marrow and well within the range for therapeutic efficacy on tumors. Astatinated MX35-F(ab')(2) monoclonal antibodies were administered intravenously to nude mice. Both non-tumor-bearing animals and animals bearing subcutaneous xenografts of the human ovarian cancer cell line, OVCAR-3, were used. The animals received approximately 0.4, 0.8, or 1.2 MBq in one, two, or three fractions. The mean absorbed doses to the kidneys ranged from 1.5 to 15 Gy. The renal function was studied by serial GFR measurements, using plasma clearance of (51)Cr-EDTA, up to 67 weeks after the first astatine injection. A dose-dependent effect on GFR was found and at the time interval 8-30 weeks after the first administration of astatine, the absorbed doses causing a 50% decrease in GFR were 16.4 +/- 3.3 and 14.0 +/- 4.1 Gy (mean +/- SEM), tumor- and non-tumor-bearing animals, respectively. The reduction in GFR progressed with time, and at the later time interval, (31-67 weeks) the corresponding absorbed doses were 7.5 +/- 2.4 and 11.3 +/- 2.3 Gy, respectively, suggesting that the effects of radiation on the kidneys were manifested late. Examination of the kidney sections showed histologic changes that were overall subdued. Following alpha-RIT with (211)At-MX35-F(ab')(2) at levels close to the dose limit of severe myelotoxicity, the effects found on renal function were relatively small, with only minor to moderate reductions in GFR. These results suggest that a mean absorbed dose to the kidneys of approximately 10 Gy is acceptable, and that the kidneys would not be the primary dose-limiting organ in systemic alpha-RIT when using (211)At-MX35-F(ab')(2).
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| 6. |
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| 7. |
- Demirbay, Baris, et al.
(författare)
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Photo-physical characterization of high triplet yield brominated fluoresceins by transient state (TRAST) spectroscopy
- 2023
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Ingår i: Methods and applications in fluorescence. - : IOP Publishing. - 2050-6120. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- Photo-induced dark transient states of fluorophores can pose a problem in fluorescence spectroscopy. However, their typically long lifetimes also make them highly environment sensitive, suggesting fluorophores with prominent dark-state formation yields to be used as microenvironmental sensors in bio-molecular spectroscopy and imaging. In this work, we analyzed the singlet-triplet transitions of fluorescein and three synthesized carboxy-fluorescein derivatives, with one, two or four bromines linked to the anthracence backbone. Using transient state (TRAST) spectroscopy, we found a prominent internal heavy atom (IHA) enhancement of the intersystem crossing (ISC) rates upon bromination, inferred by density functional theory calculations to take place via a higher triplet state, followed by relaxation to the lowest triplet state. A corresponding external heavy atom (EHA) enhancement was found upon adding potassium iodide (KI). Notably, increased KI concentrations still resulted in lowered triplet state buildup in the brominated fluorophores, due to relatively lower enhancements in ISC, than in the triplet decay. Together with an antioxidative effect on the fluorophores, adding KI thus generated a fluorescence enhancement of the brominated fluorophores. By TRAST measurements, analyzing the average fluorescence intensity of fluorescent molecules subject to a systematically varied excitation modulation, dark state transitions within very high triplet yield (>90%) fluorophores can be directly analyzed under biologically relevant conditions. These measurements, not possible by other techniques such as fluorescence correlation spectroscopy, opens for bio-sensing applications based on high triplet yield fluorophores, and for characterization of high triplet yield photodynamic therapy agents, and how they are influenced by IHA and EHA effects.
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| 8. |
- Ejserholm, Fredrik, et al.
(författare)
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A polymer neural probe with tunable flexibility
- 2013
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Ingår i: 2013 6th International IEEE/EMBS Conference on Neural Engineering (NER). - 1948-3546. - 9781467319690 ; , s. 691-694
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Konferensbidrag (refereegranskat)abstract
- A novel polymeric material, off stoichiometry thiol-ene-epoxy (OSTE+), has been evaluated for the fabrication of neural implants. OSTE+ is easily photo-structurable and exhibits mechanical properties suitable for stable implantation of the probe into brain tissue, while being sufficiently soft at physiological temperatures to reduce living tissue damage. The facile processing of OSTE+ allows use in applications where SU-8 or polyimide currently are the materials of choice. Uniquely, OSTE+ has a Young’s modulus of 1.9 GPa at 10 °C decreasing almost two orders of magnitude to 30 MPa at 40 °C, which can be compared to the Young’s modulus of 2.1 GPa for SU-8. We show a probe, with nine gold electrode sites, implanted into 0.5% agar at 40 °C using active cooling during the implantation.
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| 9. |
- Giovannucci, Tatiana A., et al.
(författare)
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Identification of a novel compound that simultaneously impairs the ubiquitin-proteasome system and autophagy
- 2022
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Ingår i: Autophagy. - : Taylor & Francis. - 1554-8627 .- 1554-8635. ; 18:7, s. 1486-1502
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Tidskriftsartikel (refereegranskat)abstract
- The ubiquitin-proteasome system (UPS) and macroautophagy/autophagy are the main proteolytic systems in eukaryotic cells for preserving protein homeostasis, i.e., proteostasis. By facilitating the timely destruction of aberrant proteins, these complementary pathways keep the intracellular environment free of inherently toxic protein aggregates. Chemical interference with the UPS or autophagy has emerged as a viable strategy for therapeutically targeting malignant cells which, owing to their hyperactive state, heavily rely on the sanitizing activity of these proteolytic systems. Here, we report on the discovery of CBK79, a novel compound that impairs both protein degradation by the UPS and autophagy. While CBK79 was identified in a high-content screen for drug-like molecules that inhibit the UPS, subsequent analysis revealed that this compound also compromises autophagic degradation of long-lived proteins. We show that CBK79 induces non-canonical lipidation of MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 beta) that requires ATG16L1 but is independent of the ULK1 (unc-51 like autophagy activating kinase 1) and class III phosphatidylinositol 3-kinase (PtdIns3K) complexes. Thermal preconditioning of cells prevented CBK79-induced UPS impairment but failed to restore autophagy, indicating that activation of stress responses does not allow cells to bypass the inhibitory effect of CBK79 on autophagy. The identification of a small molecule that simultaneously impairs the two main proteolytic systems for protein quality control provides a starting point for the development of a novel class of proteostasis-targeting drugs.
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| 10. |
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