title: 3-Aminopyrazole inhibitors of CDK2/cyclin A as antitumor agents. 2. Lead optimization.
abstract: Inhibitors of cyclin-dependent kinases (CDK) such as CDK2/cyclin A-E are currently undergoing clinical trials to verify their potential as new anticancer agents. In a previous article we described the lead discovery process of a 3-aminopyrazole class of CDK2/cyclin A-E inhibitors. The endpoint of this process was PNU-292137, a compound endowed with in vivo antitumor activity in a mouse tumor xenograft model. We optimized this lead compound to improve some physicochemical properties, notably solubility and plasma protein binding. This lead optimization process brought us to the discovery of (2S)-N-(5-cyclopropyl-1H-pyrazol-3-yl)-2-[4-(2-oxo-1-pyrrolidinyl)phenyl]propanamide (PHA-533533, 13), a compound with a balanced activity vs druglike profile. Compound 13 inhibited CDK2/cyclin A with a K(i) of 31 nM, counteracting tumor cell proliferation of different cell lines with an IC(50) in the submicromolar range. Solubility was improved more than 10 times over the starting lead, while plasma protein binding was decreased from 99% to 74%. With exploitation of this globally enhanced in vitro profile, 13 was more active than PNU-292137 in vivo in the A2780 xenograft model showing a tumor growth inhibition of 70%. Proof of mechanism of action was obtained in vivo by immunohistochemical analysis of tumor slices of 13-treated vs untreated animals.
authors.affiliation: Department Chemistry, Nerviano Medical Sciences, BU-Oncology and BU-Preclinical Science, Viale Pasteur 10, 20014 Nerviano (MI), Italy. paolo.pevarello@nervianoms.com
authors.forename: Paolo
authors.initials: P
authors.lastname: Pevarello
authors.forename: Maria Gabriella
authors.initials: MG
authors.lastname: Brasca
authors.forename: Paolo
authors.initials: P
authors.lastname: Orsini
authors.forename: Gabriella
authors.initials: G
authors.lastname: Traquandi
authors.forename: Antonio
authors.initials: A
authors.lastname: Longo
authors.forename: Marcella
authors.initials: M
authors.lastname: Nesi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Orzi
authors.forename: Claudia
authors.initials: C
authors.lastname: Piutti
authors.forename: Pietro
authors.initials: P
authors.lastname: Sansonna
authors.forename: Mario
authors.initials: M
authors.lastname: Varasi
authors.forename: Alexander
authors.initials: A
authors.lastname: Cameron
authors.forename: Anna
authors.initials: A
authors.lastname: Vulpetti
authors.forename: Fulvia
authors.initials: F
authors.lastname: Roletto
authors.forename: Rachele
authors.initials: R
authors.lastname: Alzani
authors.forename: Marina
authors.initials: M
authors.lastname: Ciomei
authors.forename: Clara
authors.initials: C
authors.lastname: Albanese
authors.forename: Wilma
authors.initials: W
authors.lastname: Pastori
authors.forename: Aurelio
authors.initials: A
authors.lastname: Marsiglio
authors.forename: Enrico
authors.initials: E
authors.lastname: Pesenti
authors.forename: Francesco
authors.initials: F
authors.lastname: Fiorentini
authors.forename: Jim R
authors.initials: JR
authors.lastname: Bischoff
authors.forename: Ciro
authors.initials: C
authors.lastname: Mercurio
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D001798:Blood Proteins / Q000378:metabolism; D042846:CDC2-CDC28 Kinases / Q000037:antagonists & inhibitors*; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019925:Cyclin A / Q000037:antagonists & inhibitors*; D051357:Cyclin-Dependent Kinase 2; D004354:Drug Screening Assays, Antitumor; D019073:HT29 Cells; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D008819:Mice, Nude; D008958:Models, Molecular; D010539:Permeability; D010766:Phosphorylation; D011485:Protein Binding; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D011760:Pyrrolidinones / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D051381:Rats; D016160:Retinoblastoma Protein / Q000378:metabolism; D012995:Solubility; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014183:Transplantation, Heterologous
chemical_list: D000970:Antineoplastic Agents; D001798:Blood Proteins; D019925:Cyclin A; C500624:N-(5-cyclopropyl-1H-pyrazol-3-yl)-2-(4-(2-oxo-1-pyrrolidinyl)phenyl)propanamide; D011720:Pyrazoles; D011760:Pyrrolidinones; D016160:Retinoblastoma Protein; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; C495892:Cdk2 protein, rat; D051357:Cyclin-Dependent Kinase 2