Apoptosis-related gene transcription in human A549 lung cancer cells via A(3) adenosine receptor

Cell Physiol Biochem. 2012;29(5-6):687-96. doi: 10.1159/000312589. Epub 2012 May 11.


Background/aims: 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.

Conclusion: 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.

MeSH terms

  • Adenosine / pharmacology
  • Apoptosis* / drug effects
  • Base Sequence
  • Cell Line, Tumor
  • Flow Cytometry
  • Humans
  • In Situ Nick-End Labeling
  • RNA, Small Interfering
  • Real-Time Polymerase Chain Reaction
  • Receptor, Adenosine A3 / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription, Genetic*


  • RNA, Small Interfering
  • Receptor, Adenosine A3
  • Adenosine