title: Therapeutic efficacy of a new topoisomerase I and II inhibitor TAS-103, against both P-glycoprotein-expressing and -nonexpressing drug-resistant human small-cell lung cancer.
abstract: We examined the effect of a novel topoisomerase I and II (topo I and II) inhibitor, TAS-103, on P-glycoprotein (P-gp)-expressing and -nonexpressing drug-resistant human small-cell lung cancer (SCLC) cells in vitro and in vivo. We observed that TAS-103 was effective in inhibiting in vitro proliferation of human SCLC (SBC-3 and H69) cells and their drug-resistant variants SBC-3/ADM or SBC-3/CDDP and H-69/VP, respectively. SBC-3/ADM and H-69/VP expressed high P-gp, whereas SBC-3/CDDP did not. TAS-103 also effectively reduced the tumor growth (more than 50% inhibition) of the parental as well as MDR SCLC cells grown SC in nude mice. Adriamycin (ADM) and cisplatin (CDDP), on the other hand, were effective only against the parental cells, while these drugs failed to inhibit the respective drug-resistant variants in vitro or in vivo. TAS-103 was observed to induce apoptosis dose dependently in the parental as well as drug-resistant SCLC cells as analyzed after 48 h of in vitro treatment, suggesting that the stabilization of cleavable topo I- or II-DNA complexes by topo I and II inhibitors like TAS-103 is followed by apoptosis of the cells. Overall, our study suggests that TAS-103 may have clinical application against drug-resistant human SCLC.
authors.affiliation: Third Department of Internal Medicine, University of Tokushima School of Medicine, Japan.
authors.forename: P
authors.initials: P
authors.lastname: Parajuli
authors.forename: S
authors.initials: S
authors.lastname: Yano
authors.forename: Y
authors.initials: Y
authors.lastname: Nishioka
authors.forename: H
authors.initials: H
authors.lastname: Nokihara
authors.forename: M
authors.initials: M
authors.lastname: Hanibuchi
authors.forename: N
authors.initials: N
authors.lastname: Nishimura
authors.forename: T
authors.initials: T
authors.lastname: Utsugi
authors.forename: S
authors.initials: S
authors.lastname: Sone
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000187:drug effects / Q000378:metabolism; D000634:Aminoquinolines / Q000627:therapeutic use*; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis; D018288:Carcinoma, Small Cell / Q000188:drug therapy*; D019008:Drug Resistance, Neoplasm; D006801:Humans; D007192:Indenes / Q000627:therapeutic use*; D008175:Lung Neoplasms / Q000188:drug therapy*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000187:drug effects / Q000378:metabolism; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000634:Aminoquinolines; D000970:Antineoplastic Agents; D007192:Indenes; D009363:Neoplasm Proteins; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; C106647:6-((2-(dimethylamino)ethyl)amino)-3-hydroxy-7H-indeno(2,1-c)quinolin-7-one