title: 2-aroylindoles, a novel class of potent, orally active small molecule tubulin inhibitors.
abstract: 2-Aroylindoles with 5-methoxy-1H-2-indolyl-phenylmethanone (D-64131) as the lead structure were discovered as a new class of synthetic, small molecule tubulin inhibitors. By competitively binding with [(3)H]colchicine to alphabeta-tubulin and inhibiting microtubule formation, cycling cells were arrested in the G(2)-M phase of the cell division cycle. The proliferation of tumor cells from 12 of 14 different organs and tissues was inhibited with mean IC(50)s of 62 nM and 24 nM by D-64131 and D-68144, respectively, comparable with the potency of paclitaxel with mean IC(50) of 10 nM. By measuring the cytotoxicity in a human colon carcinoma cell model with ectopic ecdysone-inducible expression of the cyclin-dependent kinase inhibitor p21(WAF1), specificity toward cycling cells was demonstrated. In contrast to microtubule inhibitors from natural sources, 2-aroylindoles did not alter the polymerization-dependent GTPase activity of beta-tubulin and are not substrates of the multidrug resistance/multidrug resistance protein efflux pump. No cross-resistance toward cell lines with multidrug resistance/multidrug resistance protein independent resistance phenotypes became evident. In animal studies, no signs of systemic toxicity were observed after p.o. dosages of up to 400 mg/kg of D-64131. In xenograft experiments with the human amelanoic melanoma MEXF 989, D-64131 was highly active with treatment resulting in a growth delay of 23.4 days at 400 mg/kg. Therefore, D-64131 and analogues have the potential to be developed for cancer therapy, replacing or supplementing standard therapy regimens with tubulin-targeting drugs from natural sources.
authors.affiliation: ASTA Medica Oncology, D-60314 Frankfurt/Main, Germany. t.beckers@vff.uni-frankfurt.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Beckers
authors.forename: Thomas
authors.initials: T
authors.lastname: Reissmann
authors.forename: Mathias
authors.initials: M
authors.lastname: Schmidt
authors.forename: Angelika M
authors.initials: AM
authors.lastname: Burger
authors.forename: Heinz H
authors.initials: HH
authors.lastname: Fiebig
authors.forename: Udo
authors.initials: U
authors.lastname: Vanhoefer
authors.forename: Herwig
authors.initials: H
authors.lastname: Pongratz
authors.forename: Harald
authors.initials: H
authors.lastname: Hufsky
authors.forename: Jörg
authors.initials: J
authors.lastname: Hockemeyer
authors.forename: Markus
authors.initials: M
authors.lastname: Frieser
authors.forename: Siavosh
authors.initials: S
authors.lastname: Mahboobi
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D016195:G2 Phase / Q000187:drug effects; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007211:Indoles / Q000378:metabolism / Q000494:pharmacology*; D018328:Melanoma, Amelanotic / Q000188:drug therapy / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D008938:Mitosis / Q000187:drug effects; D014404:Tubulin / Q000378:metabolism; D050257:Tubulin Modulators; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: C459681:5-methoxy-1H-2-indolylphenylmethanone; D018435:ATP Binding Cassette Transporter, Subfamily B; D000970:Antineoplastic Agents; D007211:Indoles; D014404:Tubulin; D050257:Tubulin Modulators; D020558:GTP Phosphohydrolases