Description
Multiple gene expression studies have demonstrated that breast cancer biological diversity is associated with distinct transcriptional programs. Transcription factors, because of their unique ability to coordinate the expression of multiple genes, are speculated to play a role in generating phenotypic plasticity associated with cancer progression including acquired drug resistance. Combinatorial libraries of artificial zinc-finger transcription factors (ZF-TFs) provide a robust means 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 a fulvestrant, a clinically important anti-endocrine therapeutic agent. 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 ZF-TF-transduced breast cancer cell lines revealed a 72-gene cluster that constituted a common signature for the fulvestrant-resistance phenotype. Pathway enrichment-analysis of gene expression data revealed that the ZF-TF-induced fulvestrant resistance is associated with an estrogen receptor negative-like gene set and four unique myb-regulated gene sets. Furthermore, we identified a set of genes strongly expressed in the ZF-TF-induced fulvestrant-resistant cells that was correlated with a lower probability of distant metastasis-free or death-from-relapse-free survival of breast cancer patients.