title: A tamoxifen derivative, N,N-diethyl-2-[4-(phenylmethyl) phenoxy] ethanamine, selectively targets P-glycoprotein-positive multidrug resistant Chinese hamster cells.
abstract: DPPE, a tamoxifen derivative with antihistamine activity, was previously shown to potentiate the toxicity of chemotherapeutic drugs. Recently, a Phase III clinical study using doxorubicin with DPPE demonstrated significant increase in the overall survival of breast cancer patients. In this study we examined the effects of DPPE alone on the growth of drug sensitive and P-gp positive CHO cell line. Our results demonstrate DPPE is selectively toxic to P-gp positive cells and the sensitivity to DPPE alone correlated with the levels of P-gp expression. Moreover, in MDR cells, DPPE-induced apoptosis was significantly reduced with Bcl2 overexpression and in the presence of P-gp ATPase inhibitor, PSC833. Furthermore, knockdown of P-gp expression in MDR cells with P-gp-siRNA reversed DPPE sensitivity and increased their sensitivity to doxorubicin and taxol but not to cisplatin. The addition of DPPE to membrane fractions led to dose-dependent increase in P-gp ATPase that was inhibited with PSC833. Moreover, incubation of P-gp positive cells with DPPE led to a significant increase in superoxide levels and a drop in cellular ATP and GSH pools that were reversible with inhibitors of P-gp ATPase. The combined presence of DPPE and the mitochondria electron transport complex III inhibitor, antimycin A, synergized in their effects on the growth of MDR cells but had no effect on the growth of parental drug sensitive cells. Collectively, the results of this study provide a possible mechanism that may be relevant to the clinical results of DPPE in breast cancer trial and demonstrates DPPE as P-gp collateral sensitivity drug.
authors.affiliation: Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue (Montreal), Quebec, Canada H9X-3V9. Electronic address: Elias.Georges@McGill.CA.
authors.forename: Elias
authors.initials: E
authors.lastname: Georges
authors.affiliation: Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue (Montreal), Quebec, Canada H9X-3V9.
authors.forename: Jing
authors.initials: J
authors.lastname: Lian
authors.affiliation: Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue (Montreal), Quebec, Canada H9X-3V9.
authors.forename: Remi
authors.initials: R
authors.lastname: Laberge
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001559:Benzhydryl Compounds / Q000494:pharmacology*; D016466:CHO Cells; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002945:Cisplatin / Q000494:pharmacology; D003412:Cricetulus; D003524:Cyclosporins / Q000494:pharmacology; D004317:Doxorubicin / Q000494:pharmacology*; D018432:Drug Resistance, Multiple; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005021:Ethylamines / Q000494:pharmacology*; D005786:Gene Expression Regulation; D005978:Glutathione / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology*; D010647:Phenyl Ethers; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D013481:Superoxides / Q000819:agonists / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D001559:Benzhydryl Compounds; D003524:Cyclosporins; D004791:Enzyme Inhibitors; D005021:Ethylamines; D010647:Phenyl Ethers; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D013481:Superoxides; D000968:Antimycin A; D004317:Doxorubicin; D000255:Adenosine Triphosphate; D005978:Glutathione; C043062:tesmilifene; D017239:Paclitaxel; D002945:Cisplatin; C070272:valspodar
keywords: ABCB1; ATPase; Anti-histaminic, Tamoxifen derivative; Collateral sensitivity; DPPE; Drug resistance; P-glycoprotein; ROS