title: Induction of stable drug resistance in human breast cancer cells using a combinatorial zinc finger transcription factor library.
abstract: Combinatorial libraries of artificial zinc-finger transcription factors (ZF-TFs) provide a robust tool for inducing and understanding various functional components of the cancer phenotype. Herein, we utilized combinatorial ZF-TF library technology to better understand how breast cancer cells acquire resistance to fulvestrant, a clinically important anti-endocrine therapeutic agent. From a diverse collection of nearly 400,000 different ZF-TFs, we isolated six ZF-TF library members capable of inducing stable, long-term anti-endocrine drug-resistance in two independent estrogen receptor-positive breast cancer cell lines. Comparative gene expression profile analysis of the six different ZF-TF-transduced breast cancer cell lines revealed five distinct clusters of differentially expressed genes. One cluster was shared among all 6 ZF-TF-transduced cell lines and therefore constituted a common fulvestrant-resistant gene expression signature. Pathway enrichment-analysis of this common fulvestrant resistant signature also revealed significant overlap with gene sets associated with an estrogen receptor-negative-like state and with gene sets associated with drug resistance to different classes of breast cancer anti-endocrine therapeutic agents. Enrichment-analysis of the four remaining unique gene clusters revealed overlap with myb-regulated genes. Finally, we also demonstrated that the common fulvestrant-resistant signature is associated with poor prognosis by interrogating five independent, publicly available human breast cancer gene expression datasets. Our results demonstrate that artificial ZF-TF libraries can be used successfully to induce stable drug-resistance in human cancer cell lines and to identify a gene expression signature that is associated with a clinically relevant drug-resistance phenotype.
authors.affiliation: Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America.
authors.forename: Jeongeun
authors.initials: J
authors.lastname: Lee
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Hirsh
authors.forename: Ben S
authors.initials: BS
authors.lastname: Wittner
authors.forename: Morgan L
authors.initials: ML
authors.lastname: Maeder
authors.forename: Rajasekhar
authors.initials: R
authors.lastname: Singavarapu
authors.forename: Magdalena
authors.initials: M
authors.lastname: Lang
authors.forename: Sailajah
authors.initials: S
authors.lastname: Janarthanan
authors.forename: Ultan
authors.initials: U
authors.lastname: McDermott
authors.forename: Vijay
authors.initials: V
authors.lastname: Yajnik
authors.forename: Sridhar
authors.initials: S
authors.lastname: Ramaswamy
authors.forename: J Keith
authors.initials: JK
authors.lastname: Joung
authors.forename: Dennis C
authors.initials: DC
authors.lastname: Sgroi
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology*; D045744:Cell Line, Tumor; D016000:Cluster Analysis; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D000077267:Fulvestrant; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D019151:Peptide Library; D014157:Transcription Factors / Q000378:metabolism*; D016896:Treatment Outcome; D016335:Zinc Fingers
chemical_list: D019151:Peptide Library; D014157:Transcription Factors; D000077267:Fulvestrant; D004958:Estradiol