title: MicroRNAs 206 and 21 cooperate to promote RAS-extracellular signal-regulated kinase signaling by suppressing the translation of RASA1 and SPRED1.
abstract: Despite the low prevalence of activating point mutation of RAS or RAF genes, the RAS-extracellular signal-regulated kinase (ERK) pathway is implicated in breast cancer pathogenesis. Indeed, in triple-negative breast cancer (TNBC), there is recurrent genetic alteration of pathway components. Using short hairpin RNA (shRNA) methods, we observed that the zinc finger transcription factor Krüppel-like factor 4 (KLF4) can promote RAS-ERK signaling in TNBC cells. Endogenous KLF4 bound to the promoter regions and promoted the expression of two microRNAs (miRs), miR-206 and miR-21 (i.e., miR-206/21). Antisense-mediated knockdown (anti-miR) revealed that miR-206/21 coordinately promote RAS-ERK signaling and the corresponding cell phenotypes by inhibiting translation of the pathway suppressors RASA1 and SPRED1. In TNBC cells, including cells with mutation of RAS, the suppression of either RASA1 or SPRED1 increased the levels of GTP-bound, wild-type RAS and activated ERK 1/2. Unlike the control cells, treatment of RASA1- or SPRED1-suppressed cells with anti-miR-206/21 had little or no impact on the level of activated ERK 1/2 or on cell proliferation and failed to suppress tumor initiation. These results identify RASA1 and SPRED1 mRNAs as latent RAS-ERK pathway suppressors that can be upregulated in tumor cells by anti-miR treatment. Consequently, KLF4-regulated miRs are important for the maintenance of RAS-ERK pathway activity in TNBC cells.
authors.affiliation: Department of Biochemistry, West Virginia University, Morgantown, West Virginia, USA Program in Cancer Cell Biology, West Virginia University, Morgantown, West Virginia, USA.
authors.forename: Sriganesh B
authors.initials: SB
authors.lastname: Sharma
authors.affiliation: Department of Biochemistry, West Virginia University, Morgantown, West Virginia, USA The Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, USA.
authors.forename: Chen-Chung
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Department of Biochemistry, West Virginia University, Morgantown, West Virginia, USA Program in Cancer Cell Biology, West Virginia University, Morgantown, West Virginia, USA.
authors.forename: Mark K
authors.initials: MK
authors.lastname: Farrugia
authors.affiliation: The Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, USA.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: McLaughlin
authors.affiliation: The Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, USA.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Ellis
authors.affiliation: The Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Brundage
authors.affiliation: The Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, USA Department of Medicine, West Virginia University, Morgantown, West Virginia, USA.
authors.forename: Mohamad A
authors.initials: MA
authors.lastname: Salkeni
authors.affiliation: Department of Biochemistry, West Virginia University, Morgantown, West Virginia, USA The Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, USA mruppert@hsc.wvu.edu.
authors.forename: J Michael
authors.initials: JM
authors.lastname: Ruppert
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D020729:p120 GTPase Activating Protein / Q000235:genetics* / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D047908:Intracellular Signaling Peptides and Proteins; C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; C546087:MIRN206 microRNA, human; C524940:MIRN21 microRNA, human; D008565:Membrane Proteins; D035683:MicroRNAs; C557248:RASA1 protein, human; C504812:SPRED1 protein, human; D020729:p120 GTPase Activating Protein; D018631:ras Proteins