title: REIC/Dkk-3 overexpression downregulates P-glycoprotein in multidrug-resistant MCF7/ADR cells and induces apoptosis in breast cancer.
abstract: The overexpression of reduced expression in immortalized cells (REIC)/Dickkopf-3 (Dkk-3), a tumor suppressor gene, induced apoptosis in human prostatic and testicular cancer cells. The aim of this study is to examine the potential of REIC/Dkk-3 as a therapeutic target against breast cancer. First, the in vitro apoptotic effect of Ad-REIC treatment was investigated in breast cancer cell lines and the adenovirus-mediated overexpression of REIC/Dkk-3 was thus found to lead to apoptotic cell death in a c-Jun-NH(2)-kinase (JNK) phosphorylaion-dependent manner. Moreover, an in vivo apoptotic effect and MCF/Wt tumor growth inhibition were observed in the mouse model after intratumoral Ad-REIC injection. As multidrug resistance (MDR) is a major problem in the chemotherapy of progressive breast cancer, the in vitro effects of Ad-REIC treatment were investigated in terms of the sensitivity of multidrug-resistant MCF7/ADR cells to doxorubicin and of the P-glycoprotein expression. Ad-REIC treatment in MCF7/ADR cells also downregulated P-glycoprotein expresssion through JNK activation, and sensitized its drug resistance against doxorubicin. Therefore, not only apoptosis induction but also the reversal of anticancer drug resistance was achieved using Ad-REIC. We suggest that REIC/Dkk-3 is a novel target for breast cancer treatment and that Ad-REIC might be an attractive agent against drug-resistant cancer in combination with conventional antineoplastic agents.
authors.affiliation: Department of Cancer and Thoracic Surgery, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kawasaki
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Sakaguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Ogasawara
authors.forename: K
authors.initials: K
authors.lastname: Ochiai
authors.forename: Y
authors.initials: Y
authors.lastname: Nasu
authors.forename: H
authors.initials: H
authors.lastname: Doihara
authors.forename: Y
authors.initials: Y
authors.lastname: Kashiwakura
authors.forename: N-h
authors.initials: NH
authors.lastname: Huh
authors.forename: H
authors.initials: H
authors.lastname: Kumon
authors.forename: H
authors.initials: H
authors.lastname: Date
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis* / Q000235:genetics; D048868:Adaptor Proteins, Signal Transducing; D000256:Adenoviridae; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D018925:Chemokines; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D004317:Doxorubicin / Q000494:pharmacology* / Q000627:therapeutic use; D018432:Drug Resistance, Multiple / Q000187:drug effects / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics; D005260:Female; D015316:Genetic Therapy; D006367:HeLa Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics; D048670:MAP Kinase Kinase 4 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D048868:Adaptor Proteins, Signal Transducing; D000903:Antibiotics, Antineoplastic; D018925:Chemokines; C498624:DKK3 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D004317:Doxorubicin; D048670:MAP Kinase Kinase 4