title: The antiproliferative and proapoptotic effects of cladosporols A and B are related to their different binding mode as PPARγ ligands.
abstract: Cladosporols are secondary metabolites from Cladosporium tenuissimum characterized for their ability to control cell proliferation. We previously showed that cladosporol A inhibits proliferation of human colon cancer cells through a PPARγ-mediated modulation of gene expression. In this work, we investigated cladosporol B, an oxidate form of cladosporol A, and demonstrate that it is more efficient in inhibiting HT-29 cell proliferation due to a robust G0/G1-phase arrest and p21(waf1/cip1) overexpression. Cladosporol B acts as a PPARγ partial agonist with lower affinity and reduced transactivation potential in transient transfections as compared to the full agonists cladosporol A and rosiglitazone. Site-specific PPARγ mutants and surface plasmon resonance (SPR) experiments confirm these conclusions. Cladosporol B in addition displays a sustained proapoptotic activity also validated by p21(waf1/cip1) expression analysis in the presence of the selective PPARγ inhibitor GW9662. In the DMSO/H2O system, cladosporols A and B are unstable and convert to the ring-opened compounds 2A and 2B. Finally, docking experiments provide the structural basis for full and partial PPARγ agonism of 2A and 2B, respectively. In summary, we report here, for the first time, the structural characteristics of the binding of cladosporols, two natural molecules, to PPARγ. The binding of compound 2B is endowed with a lower transactivation potential, higher antiproliferative and proapoptotic activity than the two full agonists as compound 2A and rosiglitazone (RGZ).
authors.affiliation: Dipartimento di Scienze e Tecnologie, Università del Sannio, via Port'Arsa 11, 82100 Benevento, Italy.
authors.forename: Diana
authors.initials: D
authors.lastname: Zurlo
authors.affiliation: Dipartimento di Scienze e Tecnologie, Università del Sannio, via Port'Arsa 11, 82100 Benevento, Italy.
authors.forename: Pamela
authors.initials: P
authors.lastname: Ziccardi
authors.affiliation: Dipartimento di Scienze e Tecnologie, Università del Sannio, via Port'Arsa 11, 82100 Benevento, Italy.
authors.forename: Carolina
authors.initials: C
authors.lastname: Votino
authors.affiliation: Dipartimento di Scienze e Tecnologie, Università del Sannio, via Port'Arsa 11, 82100 Benevento, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Colangelo
authors.affiliation: Dipartimento di Farmacia, "Drug Discovery" Laboratory, Università degli Studi di Napoli Federico II, via D. Montesano 49, 80131 Napoli, Italy.
authors.forename: Carmen
authors.initials: C
authors.lastname: Cerchia
authors.affiliation: Dipartimento di Farmacia, Università degli Studi di Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Dal Piaz
authors.affiliation: Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Dallavalle
authors.affiliation: Dipartimento di Scienze delle Produzioni Agroalimentari e dell'Ambiente (DiSPAA), Università degli Studi di Firenze, Piazzale delle Cascine 18, 50144 Firenze, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Moricca
authors.affiliation: Dipartimento di Farmacia, "Drug Discovery" Laboratory, Università degli Studi di Napoli Federico II, via D. Montesano 49, 80131 Napoli, Italy.
authors.forename: Ettore
authors.initials: E
authors.lastname: Novellino
authors.affiliation: Dipartimento di Farmacia, "Drug Discovery" Laboratory, Università degli Studi di Napoli Federico II, via D. Montesano 49, 80131 Napoli, Italy. Electronic address: antonio.lavecchia@unina.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Lavecchia
authors.affiliation: Dipartimento di Scienze e Tecnologie, Università del Sannio, via Port'Arsa 11, 82100 Benevento, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Colantuoni
authors.affiliation: Dipartimento di Scienze e Tecnologie, Università del Sannio, via Port'Arsa 11, 82100 Benevento, Italy. Electronic address: lupo@unisannio.it.
authors.forename: Angelo
authors.initials: A
authors.lastname: Lupo
mesh_terms: D000813:Anilides / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D054333:Drug Partial Agonism; D059585:G1 Phase Cell Cycle Checkpoints; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D062105:Molecular Docking Simulation; D009284:Naphthols / Q000494:pharmacology*; D018384:Oxidative Stress; D047495:PPAR gamma / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D015533:Transcriptional Activation
chemical_list: C457499:2-chloro-5-nitrobenzanilide; D000813:Anilides; D000970:Antineoplastic Agents; D050759:Cyclin-Dependent Kinase Inhibitor p21; D008024:Ligands; D009284:Naphthols; D047495:PPAR gamma; C000610716:cladosporol A; C000610717:cladosporol B
keywords: Apoptosis; Cladosporols; Colorectal cancer cells; Docking; Full and partial PPARγ agonists