Browsing by Author "Timucin, Emel"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Bridging the Bridging Imidazolate in the Bimetallic Center of the Cu/Zn SOD1 and ALS
    (FRONTIERS MEDIA SA, 2021-01-01) Timucin, Ahmet Can; Cinaroglu, Suleyman Selim; Sezerman, Osman Ugur; Timucin, Emel
    Metallation status of human Cu/Zn superoxide dismutase 1 (SOD1) plays a pivotal role in the pathogenesis of amyotrophic lateral sclerosis (ALS). All of the amino acids found in the bimetallic center have been associated with ALS except for two positions. H63 which forms the bridging imidazolate ion in the bimetallic center and K136 which is not directly involved in coordination but located in the bimetallic center were not reported to be mutated in any of the identified ALS cases. In this study, we investigated the structure and flexibility of five SOD1 variants by using classical molecular dynamics simulations. These variants include three substitutions on the non-ALS-linked positions
  • Thumbnail Image
    Item
    Molecular modelling of the FOXO4-TP53 interaction to design senolytic peptides for the elimination of senescent cancer cells
    (ELSEVIER, 2021-01-01) Le, Hillary H.; Cinaroglu, Suleyman S.; Manalo, Elise C.; Ors, Aysegul; Gomes, Michelle M.; Sahbaz, Burcin Duan; Bonic, Karla; Marmolejo, Carlos A. Origel; Quentel, Arnaud; Plaut, Justin S.; Kawashima, Taryn E.; Ozdemir, E. Sila; Malhotra V, Sanjay; Ahiska, Yavuz; Sezerman, Ugur; Akcapinar, Gunseli Bayram; Saldivar, Joshua C.; Timucin, Emel; Fischer, Jared M.
    Background: Senescent cells accumulate in tissues over time as part of the natural ageing process and the removal of senescent cells has shown promise for alleviating many different age-related diseases in mice. Cancer is an age-associated disease and there are numerous mechanisms driving cellular senescence in cancer that can be detrimental to recovery. Thus, it would be beneficial to develop a senolytic that acts not only on ageing cells but also senescent cancer cells to prevent cancer recurrence or progression. Methods: We used molecular modelling to develop a series of rationally designed peptides to mimic and target FOXO4 disrupting the FOXO4-TP53 interaction and releasing TP53 to induce apoptosis. We then tested these peptides as senolytic agents for the elimination of senescent cells both in cell culture and in vivo. Findings: Here we show that these peptides can act as senolytics for eliminating senescent human cancer cells both in cell culture and in orthotopic mouse models. We then further characterized one peptide, ES2, showing that it disrupts FOXO4-TP53 foci, activates TP53 mediated apoptosis and preferentially binds FOXO4 compared to TP53. Next, we show that intratumoural delivery of ES2 plus a BRAF inhibitor results in a significant increase in apoptosis and a survival advantage in mouse models of melanoma. Finally, we show that repeated systemic delivery of ES2 to older mice results in reduced senescent cell numbers in the liver with minimal toxicity. Interpretation: Taken together, our results reveal that peptides can be generated to specifically target and eliminate FOXO4+ senescent cancer cells, which has implications for eradicating residual disease and as a combination therapy for frontline treatment of cancer. Funding: This work was supported by the Cancer Early Detection Advanced Research Center at Oregon Health \& Science University. (C) 2021 The Authors. Published by Elsevier B.V.