title: Small Molecule Inhibition of miR-544 Biogenesis Disrupts Adaptive Responses to Hypoxia by Modulating ATM-mTOR Signaling.
abstract: Hypoxia induces a complex circuit of gene expression that drives tumor progression and increases drug resistance. Defining these changes allows for an understanding of how hypoxia alters tumor biology and informs design of lead therapeutics. We probed the role of microRNA-544 (miR-544), which silences mammalian target of rapamycin (mTOR), in a hypoxic breast cancer model by using a small molecule (1) that selectively impedes the microRNA's biogenesis. Application of 1 to hypoxic tumor cells selectively inhibited production of the mature microRNA, sensitized cells to 5-fluorouracil, and derepressed mRNAs affected by miR-544 in cellulo and in vivo, including boosting mTOR expression. Thus, small molecule inhibition of miR-544 reverses a tumor cell's physiological response to hypoxia. Importantly, 1 sensitized tumor cells to hypoxia-associated apoptosis at a 25-fold lower concentration than a 2'-O-methyl RNA antagomir and was as selective. Further, the apoptotic effect of 1 was suppressed by treatment of cell with rapamycin, a well-known inhibitor of the mTOR signaling pathway, illustrating the selectivity of the compound. Thus, RNA-directed chemical probes, which could also serve as lead therapeutics, enable interrogation of complex cellular networks in cells and animals.
authors.affiliation: Department of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida , Jupiter, Florida 33458, United States.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Haga
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Scripps Florida , Jupiter, Florida 33458, United States.
authors.forename: Sai Pradeep
authors.initials: SP
authors.lastname: Velagapudi
authors.affiliation: Department of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida , Jupiter, Florida 33458, United States.
authors.forename: Jacqueline R
authors.initials: JR
authors.lastname: Strivelli
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Scripps Florida , Jupiter, Florida 33458, United States.
authors.forename: Wang-Yong
authors.initials: WY
authors.lastname: Yang
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Scripps Florida , Jupiter, Florida 33458, United States.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Disney
authors.affiliation: Department of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida , Jupiter, Florida 33458, United States.
authors.forename: Donald G
authors.initials: DG
authors.lastname: Phinney
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D005786:Gene Expression Regulation; D000860:Hypoxia / Q000503:physiopathology; D051379:Mice; D035683:MicroRNAs / Q000037:antagonists & inhibitors*; D009369:Neoplasms / Q000188:drug therapy; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C000605397:MIRN-544 microRNA, mouse; D035683:MicroRNAs; D054852:Small Molecule Libraries; C546843:mTOR protein, mouse; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D058570:TOR Serine-Threonine Kinases