Contents lists available at ScienceDirect BBA - General Subjects journal homepage: www.elsevier.com/locate/bbagen SLMP53-1 interacts with wild-type and mutant p53 DNA-binding domain and reactivates multiple hotspot mutations Ana Sara Gomes a,1 , Helena Ramos a,1 , Sara Gomes a , Joana B. Loureiro a , Joana Soares a , Valentina Barcherini a , Paola Monti c , Gilberto Fronza c , Carla Oliveira d , Lucília Domingues d , Margarida Bastos e , Daniel F.A.R. Dourado f,i , Ana Luísa Carvalho g , Maria João Romão g , Benedita Pinheiro g , Filipa Marcelo g , Alexandra Carvalho h , Maria M.M. Santos b , Lucília Saraiva a, ⁎ a LAQV/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal b Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal c Mutagenesis and Cancer Prevention Unit, IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy d CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal e CIQUP, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, R. Campo Alegre, 687, P-4169-007 Porto, Portugal f School of Chemistry and Chemical Engineering, Queen's University Belfast, UK g UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal h CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal i Almac Sciences, Department of Biocatalysis and Isotope Chemistry, Almac House, 20 Seagoe Industrial Estate, Craigavon BT63 5QD, UK ARTICLE INFO Keywords: p53 Mutant Cancer Chemotherapy Reactivator ABSTRACT Background: Half of human cancers harbour TP53 mutations that render p53 inactive as a tumor suppressor. As such, reactivation of mutant (mut)p53 through restoration of wild-type (wt)-like function represents one of the most promising therapeutic strategies in cancer treatment. Recently, we have reported the (S)-tryptophanol- derived oxazoloisoindolinone SLMP53-1 as a new reactivator of wt and mutp53 R280K with in vitro and in vivo p53-dependent antitumor activity. The present work aimed a mechanistic elucidation of mutp53 reactivation by SLMP53-1. Methods and results: By cellular thermal shift assay (CETSA), it is shown that SLMP53-1 induces wt and mutp53 R280K thermal stabilization, which is indicative of intermolecular interactions with these proteins. Accordingly, in silico studies of wt and mutp53 R280K DNA-binding domain with SLMP53-1 unveiled that the compound binds at the interface of the p53 homodimer with the DNA minor groove. Additionally, using yeast and p53-null tumor cells ectopically expressing distinct highly prevalent mutp53, the ability of SLMP53-1 to reactivate multiple mutp53 is evidenced. Conclusions: SLMP53-1 is a p53-activating agent with the ability to directly target wt and a set of hotspot mutp53. General Significance: This work reinforces the encouraging application of SLMP53-1 in the personalized treat- ment of cancer patients harboring distinct p53 status. 1. Introduction The tumor suppressor protein p53 coordinates a myriad of essential cellular processes, including DNA repair, cell cycle arrest, and death, mostly by acting as a transcription factor [1]. The impairment or loss of p53 is a pivotal event in cancer formation and progression [1]. In about half of human cancers, p53 is inactivated by mutation, with colorectal, head and neck, esophagus, female genital organs, pancreas and skin cancers exhibiting the highest prevalence of TP53 mutations [2,3]. The majority of TP53 mutations are missense and occur within the p53 DNA-binding domain (DBD). Despite the huge diversity of mutations in the TP53 gene, there are six hotspot amino acid residues (R175, G245, R248, R249, R273, and R282) located in (or close to) the DNA-binding surface with high clinical relevance [2,3]. Mutant p53 (mutp53) https://doi.org/10.1016/j.bbagen.2019.129440 Received 12 June 2019; Received in revised form 10 September 2019; Accepted 13 September 2019 Abbreviations: DBD, DNA-binding domain; mutp53, mutant p53; wt, wild-type; CETSA, cellular thermal shift assay; SRB, sulforhodamine B ⁎ Corresponding author. E-mail address: lucilia.saraiva@ff.up.pt (L. Saraiva). 1 These authors contributed equally to the work. BBA - General Subjects 1864 (2020) 129440 Available online 16 September 2019 0304-4165/ © 2019 Elsevier B.V. All rights reserved. T