title: The novel atypical retinoid ST1926 is active in ATRA resistant neuroblastoma cells acting by a different mechanism.
abstract: E-3-(4'-Hydroxy-3'-adamantylbiphenyl-4-yl)acrylic acid (ST1926) is a novel orally available compound belonging to the class of synthetic atypical retinoids. These agents are attracting growing attention because of their unique mechanism of antitumor action that appears different from that of classical retinoic acid. This study aims at investigating the antitumor activity of ST1926 in neuroblastoma (NB) preclinical models. In vitro, ST1926 was more cytotoxic than both its prototype, CD437 and all-trans-retinoic acid (ATRA) and it was active in the SK-N-AS cell line, which is refractory to ATRA. We showed that unlike ATRA, ST1926 does not induce morphological differentiation in NB cells where it produces indirect DNA damage, cell cycle arrest in late S-G2 phases and p53-independent programmed cell death. DNA damage was not mediated by oxidative stress and was repaired by 24h after drug removal. The SK-N-DZ cell line appeared the most sensitive to the proapoptotic activity of ST1926, probably because both the extrinsic and intrinsic pathways appear involved in the process. Studies with Z-VAD-FMK, suggested that ST1926 might also mediate caspase-independent apoptosis in NB cells. In vivo, orally administered ST1926, appeared to inhibit tumor growth of NB xenografts with tolerable toxicity. Overall, our results support the view that ST1926 might represent a good drug candidate in this pediatric tumor.
authors.affiliation: Division of Pediatric Oncology, Catholic University of Rome, Largo A Gemelli 8, 00168 Rome, Italy. labfarm2@rm.unicatt.it
authors.forename: Angela Maria
authors.initials: AM
authors.lastname: Di Francesco
authors.forename: Daniela
authors.initials: D
authors.lastname: Meco
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Torella
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Barone
authors.forename: Maurizio
authors.initials: M
authors.lastname: D'Incalci
authors.forename: Claudio
authors.initials: C
authors.lastname: Pisano
authors.forename: Paolo
authors.initials: P
authors.lastname: Carminati
authors.forename: Riccardo
authors.initials: R
authors.lastname: Riccardi
mesh_terms: D000218:Adamantane / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002934:Cinnamates / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D019008:Drug Resistance, Neoplasm; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D015394:Molecular Structure; D009447:Neuroblastoma / Q000188:drug therapy* / Q000473:pathology*; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: C472791:3-(4'-hydroxy-3'-adamantylbiphenyl-4-yl)acrylic acid; D000970:Antineoplastic Agents; D002934:Cinnamates; D014212:Tretinoin; D000218:Adamantane