title: Characterization of ARC-111 as a novel topoisomerase I-targeting anticancer drug.
abstract: 8,9-Dimethoxy-5-(2-N,N-dimethylaminoethyl)-2,3-methylenedioxy-5H-dibenzo[c,h][1,6] naphthyridin-6-one (ARC-111, topovale) is a new synthetic antitumor agent. In the current study, we show that ARC-111 is highly potent in scid mice carrying human tumor xenografts. ARC-111 was shown to be as active as camptothecin (CPT)-11 in the HCT-8 colon tumor model, and compared favorably with CPT-11 and topotecan in the SKNEP anaplastic Wilms' tumor model. In tissue culture models, ARC-111 exhibited low nM cytotoxicity against a panel of cancer cells. ARC-111 cytotoxicity as well as ARC-111-induced apoptosis was reduced >100-fold in CPT-resistant topoisomerase I (TOP1)-deficient P388/CPT45 cells as compared with P388 cells. Similarly, ARC-111 cytotoxicity was greatly reduced in CPT-resistant CPT-K5 and U937/CR cells, which express CPT-resistant mutant TOP1, suggesting that the cytotoxic target of ARC-111 is TOP1. Indeed, ARC-111, like CPT, was shown to induce reversible TOP1 cleavage complexes in tumor cells as evidenced by specific reduction of the TOP1 immunoreactive band in a band depletion assay, as well as elevation of small ubiquitin modifier-TOP1 conjugate levels and activation of 26S proteasome-mediated degradation of TOP1. Unlike CPT, ARC-111 is not a substrate for the ATP-binding cassette transporter breast cancer resistance protein. In addition, ARC-111 cytotoxicity was not significantly reduced in the presence of human serum albumin. These results suggest that ARC-111 is a promising new TOP1-targeting antitumor drug with a different drug resistance profile than CPT.
authors.affiliation: Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
authors.forename: Tsai-Kun
authors.initials: TK
authors.lastname: Li
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Houghton
authors.forename: Shyamal D
authors.initials: SD
authors.lastname: Desai
authors.forename: Parima
authors.initials: P
authors.lastname: Daroui
authors.forename: Angela A
authors.initials: AA
authors.lastname: Liu
authors.forename: Eszter S
authors.initials: ES
authors.lastname: Hars
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Ruchelman
authors.forename: Edmond J
authors.initials: EJ
authors.lastname: LaVoie
authors.forename: Leroy F
authors.initials: LF
authors.lastname: Liu
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D020552:Comet Assay; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D009287:Naphthyridines / Q000378:metabolism / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000378:metabolism; D011485:Protein Binding; D012709:Serum Albumin / Q000494:pharmacology; D059004:Topoisomerase I Inhibitors; D009396:Wilms Tumor / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D023041:Xenograft Model Antitumor Assays
chemical_list: C116614:ABCG2 protein, human; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D009287:Naphthyridines; D009363:Neoplasm Proteins; D012709:Serum Albumin; D059004:Topoisomerase I Inhibitors; C481982:topovale; D004264:DNA Topoisomerases, Type I