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Gedda, Lars
Publications (10 of 28) Show all publications
Eriksson, E. K., Edwards, K., Grad, P., Gedda, L. & Agmo Hernández, V. (2019). Osmoprotective effect of ubiquinone in lipid vesicles modelling the E.coli plasma membrane. Biochimica et Biophysica Acta - Biomembranes, 1861(7), 1388-1396
Open this publication in new window or tab >>Osmoprotective effect of ubiquinone in lipid vesicles modelling the E.coli plasma membrane
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2019 (English)In: Biochimica et Biophysica Acta - Biomembranes, ISSN 0005-2736, E-ISSN 1879-2642, Vol. 1861, no 7, p. 1388-1396Article in journal (Refereed) Published
Abstract [en]

Bacteria need to be able to adapt to sudden changes in their environment, including drastic changes in the surrounding osmolarity. Adjusting the composition of the cytoplasmic membrane is one strategy used by the cells to minimize changes in turgor pressure upon osmotic shock. Recent studies have shown that ubiquinones, lipid soluble molecules involved in cell respiration, are overproduced by bacteria grown in hyperosmotic conditions and it is thus believed that these molecules can provide with osmo-protection. Hereby we explore the mechanisms behind these observations. Liposomes with a lipid headgroup composition mimicking that of the cytoplasmic membrane of bacteria are used as suitable models. The effect of ubiquinone-10 (Q10) on water transport across the membranes is characterized using a custom developed fluorescence-based experimental approach to simultaneously determine the membrane permeability coefficient and estimate the elastic resistance of the membrane towards deformation. It is shown that both parameters are affected by the presence of ubiquinone-10. Solanesol, a molecule similar to Q10 but lacking the quinone headgroup, also provides with osmo-protection although it only improves the resistance of the membrane against deformation. The fluorescence experiments are complemented by cryogenic transmission electron microscopy studies showing that the bacterial membrane mimics tend to flatten into spheroid oblate structures when osmotically stressed, indicating lipid segregation. In agreement with its proposed osmo-protective role, the flattening process is hindered by the presence of Q10.

Keywords
Coenzyme Q10, Liposomes, Membrane elasticity, Osmotic stress, Solanesol, Water permeability
National Category
Analytical Chemistry
Research subject
Chemistry with specialization in Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-361360 (URN)10.1016/j.bbamem.2019.04.008 (DOI)31026443 (PubMedID)
Funder
Swedish Research Council, 2016-03464Swedish Cancer Society, 17 0566
Available from: 2018-09-23 Created: 2018-09-23 Last updated: 2019-06-10Bibliographically approved
Ahlgren, S., Fondell, A., Gedda, L. & Edwards, K. (2017). EGF-targeting lipodisks for specific delivery of poorly water-soluble anticancer agents to tumour cells. RSC Advances, 7(36), 22178-22186
Open this publication in new window or tab >>EGF-targeting lipodisks for specific delivery of poorly water-soluble anticancer agents to tumour cells
2017 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 36, p. 22178-22186Article in journal (Refereed) Published
Abstract [en]

Concerns regarding poor aqueous solubility, high toxicity and lack of specificity impede the translation of many hydrophobic anticancer agents into safe and effective anticancer drugs. The application of colloidal drug delivery systems, and in particular the use of lipid-based nanocarriers, has been identified as a promising means to overcome these issues. PEG-stabilized lipid nanodisks (lipodisks) have lately emerged as a novel type of biocompatible, nontoxic and adaptable drug nanocarrier. In this study we have explored the potential of lipodisks as a platform for formulation and tumour targeted delivery of hydrophobic anticancer agents. Using curcumin as a model compound, we show that lipodisks can be loaded with substantial amounts of hydrophobic drugs (curcumin/lipid molar ratio 0.15). We demonstrate moreover that by deliberate choice of preparation protocols the lipodisks can be provided with relevant amounts of targeting proteins, such as epidermal growth factor (EGF). Data from in vitro cell studies verify that such EGF-decorated curcumin-loaded lipodisks are capable of EGF-receptor specific targeting of human A-431 tumour cells, and strongly suggest that the interaction between the lipodisks and the tumour cells results in receptor-mediated internalization of the disks and their cargo.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-323680 (URN)10.1039/c7ra04059h (DOI)000400157700020 ()
Available from: 2017-06-08 Created: 2017-06-08 Last updated: 2017-11-29Bibliographically approved
Piskounova, S., Gedda, L., Hulsart-Billström, G., Hilborn, J. & Bowden, T. (2014). Characterization of recombinant human bone morphogenetic protein-2 delivery from injectable hyaluronan-based hydrogels by means of I-125-radiolabelling. Journal of Tissue Engineering and Regenerative Medicine, 8(10), 821-830
Open this publication in new window or tab >>Characterization of recombinant human bone morphogenetic protein-2 delivery from injectable hyaluronan-based hydrogels by means of I-125-radiolabelling
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2014 (English)In: Journal of Tissue Engineering and Regenerative Medicine, ISSN 1932-6254, E-ISSN 1932-7005, Vol. 8, no 10, p. 821-830Article in journal (Refereed) Published
Abstract [en]

This study presents a thorough in vitro and in vivo characterization of the delivery of bone morphogenetic protein 2 (BMP-2) from a hyaluronan-based hydrogel system. The in vitro release of BMP-2 from similar hydrogels has previously been studied by enzyme-linked immunosorbent assay (ELISA), by which only a fraction of the loaded protein is detected. In the current study, I-125 radiolabelling was used instead to monitor BMP-2 in vitro and in vivo. To minimize protein loss during handling, I-125-BMP-2 adsorption to different tubes was studied at different times and temperatures. The data showed that Protein LoBind tubes exhibited the lowest protein affinity. Furthermore, a biphasic release profile of biologically active BMP-2 was observed both in vitro and in vivo, with the initial fast phase during the first week, followed by a slower release during the remaining 3 weeks. The initial fast-release phase corresponded to the early bone formation observed after 8 days in an ectopic model in rats. Bone volume and mineral content increased until day 14, after which a decrease in bone volume was observed, possibly due to resorption in response to decreased amounts of released BMP-2. Overall, the results suggested that cautious protein handling and a reliable quantification technique are essential factors for successful design of a BMP-2 delivery system.

Keywords
BMP-2 delivery, radioactive labeling, hyaluronan hydrogels, reproducibility, ectopic bone formation, protein adsorption
National Category
Biomaterials Science
Research subject
Chemistry with specialization in Polymer Chemistry
Identifiers
urn:nbn:se:uu:diva-158961 (URN)10.1002/term.1584 (DOI)000343059700009 ()22927307 (PubMedID)
Available from: 2011-09-19 Created: 2011-09-19 Last updated: 2018-12-04
Stenfelt, S., Hulsart-Billström, G., Gedda, L., Bergman, K., Larsson, S., Hilborn, J. & Bowden, T. (2014). Pre-incubation of chemically crosslinked hyaluronan-based hydrogels, loaded with BMP-2 and hydroxyapatite, and its effect on ectopic bone formation. Journal of materials science. Materials in medicine, 25(4), 1013-1023
Open this publication in new window or tab >>Pre-incubation of chemically crosslinked hyaluronan-based hydrogels, loaded with BMP-2 and hydroxyapatite, and its effect on ectopic bone formation
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2014 (English)In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 25, no 4, p. 1013-1023Article in journal (Refereed) Published
Abstract [en]

The effects of pre-incubation of hyaluronan hydrogels, for different lengths of time after the initiation of chemical crosslinking and prior to injection, were explored both by investigating the in vitro BMP-2 release kinetics from the hydrogel and by studying the ectopic bone formation in rats. From the curing profile, obtained from rheological analysis, appropriate pre-incubation times (1 min, 5 h and 3 days) were selected, to prepare slightly, moderately and fully cured hydrogels. Comparable release profiles were observed for all three test groups in vitro. Furthermore, radiography, pQCT and histology of the explanted grafts showed cancellous bone formation in all groups after 5 weeks in vivo. However, longer pre-incubation times gave rise to an increase in bone volume, but a decrease in bone density. Moreover, the 5 h and the 3 days grafts appeared to be more ordered and resistant to deformation from the surrounding tissue than the 1 min grafts. The observed variations in mechanical and biological properties could potentially be used to adapt the treatment for a specific indication.

National Category
Biomaterials Science
Research subject
Chemistry with specialization in Polymer Chemistry
Identifiers
urn:nbn:se:uu:diva-158963 (URN)10.1007/s10856-014-5147-y (DOI)000333093300006 ()
Available from: 2011-09-19 Created: 2011-09-19 Last updated: 2018-12-04
Gedda, L., Björkelund, H., Lebel, L., Asplund, A., Dubois, L., Wester, K., . . . Andersson, K. (2013). Evaluation of Real-Time Immunohistochemistry and Interaction Map as an Alternative Objective Assessment of HER2 Expression in Human Breast Cancer Tissue. Applied immunohistochemistry & molecular morphology (Print), 21(6), 497-505
Open this publication in new window or tab >>Evaluation of Real-Time Immunohistochemistry and Interaction Map as an Alternative Objective Assessment of HER2 Expression in Human Breast Cancer Tissue
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2013 (English)In: Applied immunohistochemistry & molecular morphology (Print), ISSN 1541-2016, E-ISSN 1533-4058, Vol. 21, no 6, p. 497-505Article in journal (Refereed) Published
Abstract [en]

Immunohistochemical study (IHC) is a critical tool in the clinical diagnosis of breast cancer. One common assessment is the expression level of the HER2 receptor in breast cancer tissue samples with the aim of stratifying patients for applicability of the therapeutic antibody Herceptin. In this study, we aimed to investigate whether a novel assay, real-time IHC combined with Interaction Map analysis, offers the possibility of objective assessment of HER2 expression. Interaction Map presents real-time interaction data as a collection of peaks on a surface, and it was performed on 20 patient tissue samples previously scored for HER2 expression. The result shows that the relative weight of the peaks in the maps contains novel information that could discriminate between high and low HER2 expression in an operator-independent manner (P<0.001). We conclude that the real-time IHC assay has a promising potential to complement conventional IHC and may improve the precision in the future clinical diagnostics of breast cancer.

Keywords
antibody, HER2, immunohistochemistry, IHC, kinetics, real time, tissue
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-212827 (URN)10.1097/PAI.0b013e318281162d (DOI)000327212100004 ()
Available from: 2013-12-18 Created: 2013-12-16 Last updated: 2018-12-04
Hulsart-Billström, G., Piskounova, S., Gedda, L., Andersson, B.-M., Bergman, K., Hilborn, J., . . . Bowden, T. (2013). Morphological differences in BMP-2-induced ectopic bone between solid and crushed hyaluronan hydrogel templates. Journal of materials science. Materials in medicine, 24(5), 1201-1209
Open this publication in new window or tab >>Morphological differences in BMP-2-induced ectopic bone between solid and crushed hyaluronan hydrogel templates
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2013 (English)In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, no 5, p. 1201-1209Article in journal (Refereed) Published
Abstract [en]

The possibility to affect bone formation by using crushed versus solid hydrogels as carriers for bone morphogenetic protein 2 (BMP-2) was studied. Hydrogels, based on chemical crosslinking between hyaluronic acid and poly(vinyl alcohol) derivatives, were loaded with BMP-2 and hydroxyapatite. Crushed and solid forms of the gels were analyzed both in vitro via a release study using I-125 radioactive labeling of BMP-2, and in vivo in a subcutaneous ectopic bone model in rats. Dramatically different morphologies were observed for the ectopic bone formed in vivo in the two types of gels, even though virtually identical release profiles were observed in vitro. Solid hydrogels induced formation of a dense bone shell around non-degraded hydrogel, while crushed hydrogels demonstrated a uniform bone formation throughout the entire sample. These results suggest that by crushing the hydrogel, the construct's three-dimensional network becomes disrupted. This could expose unreacted functional groups, making the fragment's surfaces reactive and enable limited chemical fusion between the crushed hydrogel fragments, leading to similar in vitro release profiles. However, in vivo these interactions could be broken by enzymatic activity, creating a macroporous structure that allows easier cell infiltration, thus, facilitating bone formation.

National Category
Engineering and Technology Natural Sciences Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-201244 (URN)10.1007/s10856-013-4877-6 (DOI)000318510200008 ()
Available from: 2013-06-10 Created: 2013-06-10 Last updated: 2018-12-04
Björkelund, H., Gedda, L., Malmqvist, M. & Andersson, K. (2013). Resolving the EGF-EGFR interaction characteristics through a multiple-temperature, multiple-inhibitor, real-time interaction analysis approach. Molecular and Clinical Oncology, 1(2), 343-352
Open this publication in new window or tab >>Resolving the EGF-EGFR interaction characteristics through a multiple-temperature, multiple-inhibitor, real-time interaction analysis approach
2013 (English)In: Molecular and Clinical Oncology, ISSN 2049-9469, Vol. 1, no 2, p. 343-352Article in journal (Refereed) Published
Abstract [en]

Overexpression and aberrant activity of the epidermal growth factor (EGF) have been observed in various cancer types, rendering it an important target in oncology research. The interaction between EGF and its receptor (EGFR), as well as subsequent internalization, is complex and may be affected by various factors including tyrosine kinase inhibitors (TKIs). By combining real‑time binding curves produced in LigandTracer® with internalization assays conducted at different temperatures and with different TKIs, the processes of ligand binding, internalization and excretion was visualized. SKOV3 cells had a slower excretion rate compared to A431 and U343 cells, and the tested TKIs (gefitinib, lapatinib, AG1478 and erlotinib) reduced the degree of internalization. The kinetic analysis of the binding curves further demonstrated TKI‑dependent balances of EGFR monomer and dimer populations, where lapatinib promoted the monomeric form, while the other TKIs induced dimers. The dimer levels were found to be associated with the apparent affinity of the EGF‑EGFR interaction, with EGF binding stronger to EGFR dimers compared to monomers. This study analyzed how real‑time molecular interaction analysis may be utilized in combination with perturbations in order to understand the kinetics of a ligand‑receptor interaction, as well as some of its associated intracellular processes. Our multiple‑temperature and ‑inhibitor assay setup renders it possible to follow the EGFR monomer, dimer and internalized populations in a detailed manner, allowing for a new perspective of the EGFR biology.

Keywords
epidermal growth factor, tyrosine kinase inhibitors, internalization, kinetics, dimerization, heterogeneity
National Category
Medical and Health Sciences
Research subject
Medicine; Molecular Biotechnology; Medical Cell Biology
Identifiers
urn:nbn:se:uu:diva-183868 (URN)10.3892/mco.2012.37 (DOI)
Available from: 2012-11-05 Created: 2012-11-05 Last updated: 2018-12-04
Göstring, L., Malm, M., Höidén-Guthenberg, I., Frejd, F., Ståhl, S., Löfblom, J. & Gedda, L. (2012). Cellular effects of HER3-specific affibody molecules. PLoS ONE, 7(6), e40023
Open this publication in new window or tab >>Cellular effects of HER3-specific affibody molecules
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2012 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 6, p. e40023-Article in journal (Refereed) Published
Abstract [en]

Recent discoveries have led to the recognition of the epidermal growth factor receptor HER3 as a key player in cancer, and consequently this receptor has gained increased interest as a target for cancer therapy. Although practically devoid of kinase activity, signaling via this receptor is often seen in tumours resistant to EGFR or HER2 therapy. Here, we show that two HER3-specific affibody molecules, Z5416 and Z5417, reduce heregulin-induced cell growth of the breast cancer cells MCF-7 and, to a lesser extent, SKBR‑3 cells. These affibody molecules have earlier been shown to block binding of the natural ligand heregulin (HRG) to HER3, which was confirmed here in cellular studies. Further, both Z5416 and Z5417 blocked HRG-induced HER3 and HER2 phosphorylation in MCF-7 cells, but only HER3 phosphorylation in SKBR-3 cells which have constantly active HER2.. These findings demonstrate that Z5416 and Z5417 exert an anti-proliferative effect on two breast cancer cells with either high or low HER2 expression, by inhibiting HRG-induced phosphorylation of HER3. The promising results presented in this study indicate that the HER3-binding affibody molecules may be suitable candidates for future therapy of cancers in which the interaction between HER3 and HRG plays an important role.

Keywords
HER3, heregulin, Affibody, proliferation
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-156734 (URN)10.1371/journal.pone.0040023 (DOI)000305892100176 ()
Available from: 2011-08-08 Created: 2011-08-08 Last updated: 2017-12-08Bibliographically approved
Gedda, L., Fondell, A., Lundqvist, H., Park, J. & Edwards, K. (2012). Experimental radionuclide therapy of HER2-expressing xenografts using two-step targeting Nuclisome-particles. Journal of Nuclear Medicine, 53(3), 480-487
Open this publication in new window or tab >>Experimental radionuclide therapy of HER2-expressing xenografts using two-step targeting Nuclisome-particles
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2012 (English)In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 53, no 3, p. 480-487Article in journal (Refereed) Published
Abstract [en]

The therapeutic potential of Auger-electron emitting radionuclides is strongly dependent on their close vicinity to DNA, since the energy deposition is mainly localized within a few cubic nanometers around the site of decay. Thus, apart from specificity, successful tumor therapy relies on a nuclear delivery strategy. We recently presented a two-step targeting strategy to transport Auger-electron-emitting radionuclides into the cell nucleus by means of nuclide-filled liposomes (Nuclisome particles), that is, polyethylene glycol-stabilized, tumor-cell-targeting liposomes loaded with (125)I-labeled anthracyclines. In the present study, the survival of mice intraperitoneally inoculated with human HER2-expressing SKOV-3 tumor cells and treated with HER2-targeting Nuclisome particles was studied.

METHODS:

BALB/c nu/nu mice were inoculated with 10(7) SKOV-3 cells intraperitoneally and thereafter directly injected with Nuclisome particles with increasing specific radioactivity. Groups of 10-12 mice were treated with 0.01 MBq/mouse up to 2 MBq/mouse, and survival was monitored and compared with that in control groups (n = 33). Organs were analyzed for HER2 expression and radiotoxic effects histologically. Absorbed doses were estimated using dose factors from the online Radiation Dose Assessment Resource model.

RESULTS:

The results showed a clear correlation between administered radioactive dose and survival. No such dose-dependent survival was observed for mice treated with Nuclisome particles lacking HER2-targeting ability. With HER2-targeting Nuclisome particles, a significant increase in survival, compared with that of untreated control mice, could already be seen at an administered activity of 0.1 MBq/mouse (P = 0.0301). At the highest activity administered, 2 MBq/mouse (P < 0.0001), 70% of the mice survived the study and most were tumor-free. Neither macroscopic nor microscopic radiotoxic side effects were observed. Dosimetric calculations, assuming nonreceptor targeting, revealed that the radioactive doses to normal tissues were low.

CONCLUSION:

Taken together the results show that with successful targeting to the tumor-cell nucleus it is possible to obtain a therapeutic effect from Auger-electron-emitting radionuclides administered at radioactive doses low enough to spare normal tissue from radiotoxic side effects.

National Category
Other Basic Medicine
Identifiers
urn:nbn:se:uu:diva-158992 (URN)10.2967/jnumed.111.096891 (DOI)000301194300046 ()22323773 (PubMedID)
Available from: 2011-09-20 Created: 2011-09-20 Last updated: 2018-12-04
Billström, G. H., Piskounova, S., Gedda, L., Hilborn, J., Bowden, T. & Larsson, S. (2012). Improved bone formation by altering surface area of hyaluronan-based hydrogel carrier for bone morphogenetic protein-2. Paper presented at 39th Annual Congress of the European-Calcified-Tissue-Society (ECTS), MAY 19-23, 2012, Stockholm, SWEDEN. Bone, 50, S114-S114
Open this publication in new window or tab >>Improved bone formation by altering surface area of hyaluronan-based hydrogel carrier for bone morphogenetic protein-2
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2012 (English)In: Bone, ISSN 8756-3282, E-ISSN 1873-2763, Vol. 50, p. S114-S114Article in journal, Meeting abstract (Other academic) Published
National Category
Medical and Health Sciences Polymer Chemistry
Research subject
Chemistry with specialization in Polymer Chemistry
Identifiers
urn:nbn:se:uu:diva-177449 (URN)10.1016/j.bone.2012.02.351 (DOI)000304503500324 ()
Conference
39th Annual Congress of the European-Calcified-Tissue-Society (ECTS), MAY 19-23, 2012, Stockholm, SWEDEN
Available from: 2012-12-13 Created: 2012-07-13 Last updated: 2018-12-04
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