title: Transcription Factors in Breast Cancer-Lessons From Recent Genomic Analyses and Therapeutic Implications.
abstract: Multiplatform genomic analyses have identified 93 frequently altered genes in breast cancer. Of these, as many as 49 genes are directly or indirectly involved in transcription. These include constitutive and inducible DNA-binding transcription factors (DB-TFs, 13 genes), corepressors/coactivators (14 genes), epigenetic (10), and mediator/splicing/rRNA (3) factors. At least nine additional genes are immediate upstream regulators of transcriptional cofactors. G:profiler analysis reveals that these alterations affect cell cycle, development/differentiation, steroid hormone, and chromatin modification pathways. A notable observation is that DB-TFs that mediate major oncogenic signaling (e.g., WNT, receptor tyrosine kinase (RTK), NOTCH, and HIPPO), which switch from default repression (signal OFF) to transcriptional activation (signal ON), are not altered in breast cancer. Instead, corepressors (e.g., pRb for E2F1 downstream of various proliferation signals) or upstream factors (e.g., APC and AXIN for TCF, downstream of canonical WNT signaling) are lost, or coactivators (e.g., NOTCH1/2 for CSL/RBPJk) are induced. In contrast, constitutive (MYC, TBX3) and signal-induced (TP53, FOXA1) DB-TFs that do not mediate default repression are directly altered in breast cancer. Some of these TFs have been implicated in the establishment of super-enhancers and positive transcriptional elongation. In addition, oncogenic transcription is induced by mutations affecting regulatory elements or chromatin conformation that create new TF-binding sites in promoters and enhancers of oncogenic genes to promote tumorigenesis. Here we review these diverse oncogenic alterations in TFs in BC and discuss implications for therapy.
authors.affiliation: Toronto General Research Institute, University Health Network, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada. Electronic address: eldad.zacksenhaus@utoronto.ca.
authors.forename: E
authors.initials: E
authors.lastname: Zacksenhaus
authors.affiliation: Toronto General Research Institute, University Health Network, Toronto, ON, Canada.
authors.forename: J C
authors.initials: JC
authors.lastname: Liu
authors.affiliation: Toronto General Research Institute, University Health Network, Toronto, ON, Canada.
authors.forename: Z
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou Medical University, Guiyang, Guizhou, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Yao
authors.affiliation: The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou Medical University, Guiyang, Guizhou, PR China.
authors.forename: L
authors.initials: L
authors.lastname: Xia
authors.affiliation: Toronto General Research Institute, University Health Network, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Shrestha
authors.affiliation: The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou Medical University, Guiyang, Guizhou, PR China. Electronic address: yaacovbendavid@hotmail.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Ben-David
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D005260:Female; D016678:Genome; D006801:Humans; D009857:Oncogenes; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D014157:Transcription Factors
keywords: Breast cancer; Genomic analysis; Targeted therapy; Transcription factors