title: FZD1 activates protein kinase C delta-mediated drug-resistance in multidrug-resistant MES-SA/Dx5 cancer cells.
abstract: Multidrug-resistant (MDR) cancer is a major clinical problem in chemotherapy of cancer patients. We have noted inappropriate PKCδ hypomethylation and overexpression of genes in the PKCδ/AP-1 pathway in the human uterus sarcoma drug-resistant cell line, MES-SA/Dx5 cells, which also overexpress p-glycoprotein (ABCB1). Recent studies have indicated that FZD1 is overexpressed in both multidrug-resistant cancer cell lines and in clinical tumor samples. These data have led us to hypothesize that the FZD1-mediated PKCδ signal-transduction pathway may play an important role in drug resistance in MES-SA/Dx5 cells. In this work, the PKCδ inhibitor Rottlerin was found to reduce ABCB1 expression and to inhibit the MDR drug pumping ability in the MES-SA/Dx5 cells when compared with the doxorubicin-sensitive parental cell line, MES-SA. PKCδ was up-regulated with concurrent up-regulation of the mRNA levels of the AP-1-related factors, c-JUN and c-FOS. Activation of AP-1 also correlated with up-regulation of the AP-1 downstream genes HGF and EGR1. Furthermore, AP-1 activities were reduced and the AP-1 downstream genes were down-regulated in Rottlerin-treated or PKCδ shRNA-transfected cells. MES-SA/Dx5 cells were resensitized to doxorubicin-induced toxicity by co-treatment with doxorubicin and Rottlerin or PKCδ shRNA. In addition, cell viability and drug pump-out ability were significantly reduced in the FZD1 inhibitor curcumin-treated and FZD1 shRNA-knockdown MES-SA/Dx5 cells, indicating involvement of PKCδ in FZD1-modulated ABCB1 expression pathway. Taken together, our data demonstrate that FZD1 regulates PKCδ, and the PKCδ/AP-1 signalling transduction pathway plays an important role in drug resistance in MES-SA/Dx5 cells.
authors.affiliation: Graduate Institute of Biomedical Sciences, Division of Biotechnology College of medicine, Chang Gung University,Tao-Yuan, Taiwan, Republic of China.
authors.forename: Tsai-Hsien
authors.initials: TH
authors.lastname: Hung
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, Republic of China.
authors.forename: Chuan-Mu
authors.initials: CM
authors.lastname: Chen
authors.affiliation: Graduate Institute of Biomedical Sciences, Division of Biotechnology College of medicine, Chang Gung University,Tao-Yuan, Taiwan, Republic of China; Department of Medical Biotechnology and Laboratory Science, College of medicine, Chang Gung University, Tao-Yuan, Taiwan, Republic of China; Molecular Medicine Research Center, College of medicine, Chang Gung University, Tao-Yuan, Taiwan, Republic of China.
authors.forename: Ching-Ping
authors.initials: CP
authors.lastname: Tseng
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, Republic of China.
authors.forename: Chih-Jie
authors.initials: CJ
authors.lastname: Shen
authors.affiliation: Department of Medical Biotechnology and Laboratory Science, College of medicine, Chang Gung University, Tao-Yuan, Taiwan, Republic of China.
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Wang
authors.affiliation: Department of Preclinical Sciences, Faculty of Medicine and Health Sciences and Centre for Stem Cell Research, Universiti Tunku Abdul Rahman, Selangor, Malaysia.
authors.forename: Kong-Bung
authors.initials: KB
authors.lastname: Choo
authors.affiliation: Graduate Institute of Biomedical Sciences, Division of Biotechnology College of medicine, Chang Gung University,Tao-Yuan, Taiwan, Republic of China; Department of Medical Biotechnology and Laboratory Science, College of medicine, Chang Gung University, Tao-Yuan, Taiwan, Republic of China; Molecular Medicine Research Center, College of medicine, Chang Gung University, Tao-Yuan, Taiwan, Republic of China. Electronic address: kchong@mail.cgu.edu.tw.
authors.forename: Kowit Yu
authors.initials: KY
authors.lastname: Chong
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000096:biosynthesis / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000008:administration & dosage; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D051157:Frizzled Receptors / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051745:Protein Kinase C-delta / Q000096:biosynthesis*; D012509:Sarcoma / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D015398:Signal Transduction; D014594:Uterine Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; C489740:FZD1 protein, human; D051157:Frizzled Receptors; D004317:Doxorubicin; D051745:Protein Kinase C-delta
keywords: Apoptosis; Cell cycle; Multiple drug resistance; PKC delta; Rottelerin; shRNA