title: Apoptosis-related gene transcription in human A549 lung cancer cells via A(3) adenosine receptor.
abstract: OBJECTIVE
  Extracellular adenosine induces apoptosis in a variety of cancer cells via diverse signaling pathways. The present study investigated the mechanism underlying adenosine-induced apoptosis in A549 human lung cancer cells.
  
  
  METHODS
  MTT assay, TUNEL staining, flow cytometry using propidium iodide and annexin V-FITC, real-time RTPCR, Western blotting, monitoring of mitochondrial membrane potentials, and assay of caspase-3, -8, and -9 activities were carried out in A549 cells, and the siRNA to silence the A(3) adenosine receptor-targeted gene was constructed.
  
  
  RESULTS
  Extracellular adenosine induces A549 cell apoptosis in a concentration (0.01-10 mM)-dependent manner, and the effect was inhibited by the A3 adenosine receptor inhibitor MRS1191 or knocking-down A(3) adenosine receptor. Like adenosine, the A(3) adenosine receptor agonist 2-Cl-IB-MECA also induced A549 cell apoptosis. Adenosine increased expression of mRNAs for Puma, Bax, and Bad, disrupted mitochondrial membrane potentials, and activated caspase-3 and -9 in A549 cells, and those adenosine effects were also suppressed by knocking-down A3 adenosine receptor.
  
  
  CONCLUSIONS
  Adenosine induces A549 cell apoptosis by upregulating expression of Bax, Bad, and Puma, to disrupt mitochondrial membrane potentials and to activate caspase-9 followed by the effector caspase-3, via A(3) adenosine receptor.
authors.affiliation: Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kamiya
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kanno
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Fujita
authors.forename: Akinobu
authors.initials: A
authors.lastname: Gotoh
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nishizaki
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D006801:Humans; D020287:In Situ Nick-End Labeling; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction; D043684:Receptor, Adenosine A3 / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D034741:RNA, Small Interfering; D043684:Receptor, Adenosine A3; D000241:Adenosine