Suchergebnisse

The virtual screening of a library of chalcone derivatives led us to the identification of potential new MDM2 ligands. The chalcones with the best docking scores obeying the Lipinski rule of five were subsequently prepared by base-catalyzed aldol reactions. The activity of these compounds as inhibitors of p53–MDM2 interaction was investigated using a yeast-based screening assay. Using this approach two chalcones (3 and 4) were identified as putative small molecule inhibitors of p53–MDM2 interaction. The activity of both chalcones was further investigated in a panel of human tumor cells. Chalcones 3 and 4 revealed a pronounced tumor cell growth inhibitory effect on tumor cell lines. Additionally, chalcone 4 caused alterations in the cell cycle profile, induced apoptosis and increased the levels of p53, p21 and PUMA proteins in NCI-H460 cells. Computational docking studies allowed to predict that, like nutlin-3A (a well-known small-molecule inhibitor of p53–MDM2 interaction), chalcones 3 and 4 bind to the p53-binding site of MDM2. The results here presented will be valuable for the structure-based design of novel and potent p53–MDM2 inhibitors. ; This research was partially supported by the Strategic Funding UID/Multi/04423/2013 , ERDF , COMPETE , and FCT under the projects PTDC/MAR-BIO/4694/2014, and INNOVMAR – Innovation and Sustainability in the Management and Exploitation of Marine Resources, reference NORTE-01-0145-FEDER-000035 , Research Line NOVELMAR . This work also received financial support from the European Union (FEDER funds POCI/01/0145/FEDER/007265) and National Funds (FCT/MEC, Fundação para a Ciência e Tecnologia and Ministério da Educação e Ciência) under the Partnership Agreement PT2020 UID/QUI/50006/2013 and the FCT project PTDC/DTP-FTO/1981/2014, "PEst-C/SAU/LA0003/2013", "NORTE-07-0162-FEDER-00018 – Contributos para o reforço da capacidade do IPATIMUP enquanto actor do sistema regional de inovação" and NORTE-07-0162-FEDER-000067 – Reforço e consolidação da capacidade infraestrutural do IPATIMUP para o sistema regional de inovação", both supported by ON.2 – O Novo Norte, through FEDER funds under the QREN. IPATIMUP integrates the i3S Research Unit, which is partially supported by FCT. The authors also thank FCT for the grants of R.T. Lima ( SFRH/BPD/68787/2010 ), J. Soares ( SFRH/BD/78971/2011 ), and S. Gomes ( SFRH/BD/96189/2013 ; Doctoral Programme BiotechHealth), L. Raimundo ( PD/BI/113926/2015 , Doctoral Programme BiotechHealth).

Protein kinase C (PKC) isozymes play major roles in human diseases, including cancer. Yet, the poor understanding of isozymes-specific functions and the limited availability of selective pharmacological modulators of PKC isozymes have limited the clinical translation of PKC-targeting agents. Here, we report the first small-molecule PKCd-selective activator, the 7a-acetoxy-6ß-benzoyloxy-12-O-benzoylroyleanone (Roy-Bz), which binds to the PKCd-C1-domain. Roy-Bz potently inhibited the proliferation of colon cancer cells by inducing a PKCd-dependent mitochondrial apoptotic pathway involving caspase-3 activation. In HCT116 colon cancer cells, Roy-Bz specifically triggered the translocation of PKCd but not other phorbol ester responsive PKCs. Roy-Bz caused a marked inhibition in migration of HCT116 cells in a PKCd-dependent manner. Additionally, the impairment of colonosphere growth and formation, associated with depletion of stemness markers, indicate that Roy-Bz also targets drug-resistant cancer stem cells, preventing tumor dissemination and recurrence. Notably, in xenograft mouse models, Roy-Bz showed a PKCd-dependent antitumor effect, through anti-proliferative, pro-apoptotic, and anti-angiogenic activities. Besides, Roy-Bz was non-genotoxic, and in vivo it had no apparent toxic side effects. Collectively, our findings reveal a novel promising anticancer drug candidate. Most importantly, Roy-Bz opens the way to a new era on PKC biology and pharmacology, contributing to the potential redefinition of the structural requirements of isozyme-selective agents, and to the re-establishment of PKC isozymes as feasible therapeutic targets in human diseases. ; We thank European Union (FEDER funds POCI/01/0145/FEDER/007728, FCOMP-01-0124-FEDER-028417 and POCI-01-0145-FEDER-007440, through Programa Operacional Factores de Competitividade—COMPETE) and National Funds (FCT/MEC, Fundação para a Ciência e Tecnologia and Ministério da Educação e Ciência) under the Partnership Agreement PT2020 UID/MULTI/ 04378/2013, UID/NEU/04539/2013, UID/DTP/04567/2016, and the project (3599-PPCDT) PTDC/DTP-FTO/1981/2014—POCI-01-0145-FEDER-016581, as well as Centro 2020 Regional Operational Programmes (CENTRO-01-0145-FEDER-000012: HealthyAging2020). FCT fellowships: SFRH/BD/87109/2012 (C. Bessa), SFRH/BD/117949/2016 (L. Raimundo), and SFRH/BD/128673/2017 (J. B. Loureiro).

Half of human cancers harbor TP53 mutations that render p53 inactive as a tumor suppressor. In these cancers, reactivation of mutant p53 (mutp53) through restoration of wild-type-like function constitutes a valuable anticancer therapeutic strategy. In order to search for mutp53 reactivators, a small library of tryptophanol-derived oxazoloisoindolinones was synthesized and the potential of these compounds as mutp53 reactivators and anticancer agents was investigated in human tumor cells and xenograft mouse models. By analysis of their anti-proliferative effect on a panel of p53-null NCI-H1299 tumor cells ectopically expressing highly prevalent mutp53, the compound SLMP53-2 was selected based on its potential reactivation of multiple structuralmutp53. In mutp53-Y220C-expressing hepatocellular carcinoma (HCC) cells, SLMP53-2-induced growth inhibition was mediated by cell cycle arrest, apoptosis, and endoplasmic reticulum stress response. In these cells, SLMP53-2 restored wild-type-like conformation and DNA-binding ability of mutp53-Y220C by enhancing its interaction with the heat shock protein 70 (Hsp70), leading to the reestablishment of p53 transcriptional activity. Additionally, SLMP53-2 displayed synergistic effect with sorafenib, the only approved therapy for advanced HCC. Notably, it exhibited potent antitumor activity in human HCC xenograft mouse models with a favorable toxicological profile. Collectively, SLMP53-2 is a new mutp53-targeting agent with promising antitumor activity, particularly against HCC. ; Funding: This work was supported by National Funds through Fundação para a Ciência e Tecnologia, I.P. via the projects UID/QUI/50006/2019 and PTDC/QUI-QOR/29664/2017. Acknowledgments: Authors acknowledge the financial support from European Union (FEDER funds POCI/01/0145/FEDER/007728 through Programa Operacional Factores de Competitividade—COMPETE) and National Funds (FCT/MEC, Fundação para a Ciência e Tecnologia and Ministério da Educação e Ciência) under the Partnership Agreement UID/DTP/04138/2019 (iMed.ULisboa), UID/NEU/04539/2013, UID/NEU/04539/2019. CENTRO-01-0145-FEDER-000012-HealthyAging2020, UID/BIO/04469/2019, BioTecNorte operation (NORTE-01-0145-FEDER-000004), and the projects (3599-PPCDT) PTDC/DTP-FTO/1981/2014—POCI-01-0145-FEDER-016581, and POCI-01-0145-FEDER-028736. We also thank FCT for the financial support through the grant CEECIND/01772/2017 (M. M. M. Santos), and fellowships SFRH/BD/96189/2013 (S. Gomes), PD/BD/143126/2019 (V. Barcherini), SFRH/BD/117949/2016 (L. Raimundo), SFRH/BD/119144/2016 (H. Ramos), SFRH/BD/128673/2017 (J. B. Loureiro), and the Programa Operacional Potencial Humano (POCH), specifically the BiotechHealth Programme (Doctoral Programme on Cellular and Molecular Biotechnology Applied to Health Sciences; PD/00016/2012). We also acknowledge the support from the Italian Association for Cancer Research, AIRC (IG#18985 to AI).