The Wnt receptor FZD1 mediates chemoresistance in neuroblastoma through activation of the Wnt/beta-catenin pathway.
The development of chemoresistance represents a major obstacle in the successful treatment of cancers such as neuroblastoma (NB), a particularly aggressive childhood solid tumour. The mechanisms underlying the chemoresistant phenotype in NB were addressed by gene expression profiling of two doxorubicin (DoxR)-resistant vs sensitive parental cell lines. Not surprisingly, the MDR1 gene was included in the identified upregulated genes, although the highest overexpressed transcript in both cell lines was the frizzled-1 Wnt receptor (FZD1) gene, an essential component of the Wnt/beta-catenin pathway. FZD1 upregulation in resistant variants was shown to mediate sustained activation of the Wnt/beta-catenin pathway as revealed by nuclear beta-catenin translocation and target genes transactivation. Interestingly, specific micro-adapted short hairpin RNA (shRNAmir)-mediated FZD1 silencing induced parallel strong decrease in the expression of MDR1, another beta-catenin target gene, revealing a complex, Wnt/beta-catenin-mediated implication of FZD1 in chemoresistance. The significant restoration of drug sensitivity in FZD1-silenced cells confirmed the FZD1-associated chemoresistance. RNA samples from 21 patient tumours (diagnosis and postchemotherapy), showed a highly significant FZD1 and/or MDR1 overexpression after treatment, underlining a role for FZD1-mediated Wnt/beta-catenin pathway in clinical chemoresistance. Our data represent the first implication of the Wnt/beta-catenin pathway in NB chemoresistance and identify potential new targets to treat aggressive and resistant NB.
Department of Paediatrics, University Hospital CHUV, Lausanne, Switzerland. Marjorie.Flahaut@chuv.ch
M
M
Flahaut
R
R
Meier
A
A
Coulon
K A
KA
Nardou
F K
FK
Niggli
D
D
Martinet
J S
JS
Beckmann
J-M
JM
Joseph
A
A
Mühlethaler-Mottet
N
N
Gross
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D005455:Fluorescent Antibody Technique; D051157:Frizzled Receptors / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D009447:Neuroblastoma / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D051153:Wnt Proteins / Q000235:genetics* / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics* / Q000378:metabolism
C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; C495270:CTNNB1 protein, human; C489740:FZD1 protein, human; D051157:Frizzled Receptors; D051153:Wnt Proteins; D051176:beta Catenin; D004317:Doxorubicin; D020169:Caspases