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R. Maeda



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    P1.01 - Poster Session 1 - Cancer Biology (ID 143)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P1.01-025 - Apoptosis-Related Gene Transcription in Human A549 Lung Cancer Cells via A<sub>3 </sub>Adenosine Receptor (ID 2157)

      09:30 - 16:30  |  Author(s): R. Maeda

      • Abstract

      Background
      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 receptortargeted 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 A~3~ 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 A~3~ 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.

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    P2.01 - Poster Session 2 - Cancer Biology (ID 145)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P2.01-021 - AMP Converted from Intracellularly Transported Adenosine Upregulates p53 Expression to Induce Malignant Pleural Mesothelioma Cell Apoptosis (ID 1174)

      09:30 - 16:30  |  Author(s): R. Maeda

      • Abstract

      Background
      The present study investigated adenosine-induced apoptosis in human malignant pleural mesothelioma cells.

      Methods
      MTT assay, TUNEL staining, flow cytometry using propidium iodide and annexin V-FITC, real-time RT-PCR, Western blotting, and assay of caspase-3, -8, and -9 activities were carried out using malignant pleural mesothelioma cell lines such as NCI-H28, NCI-H2052, NCI-H2452, and MSTO-211H cells, and P53 or A3 adenosine receptor was knocked-down by transfecting each siRNA into cells.

      Results
      Adenosine induced apoptosis in all the malignant pleural mesothelioma cells used here, independently of caspase activation. The adenosine effect was prevented by the adenosine transporter inhibitor dipyridamole, the adenosine kinase inhibitor ABT-702, or the A3 adenosine receptor inhibitor MRS1191. Adenosine upregulated expression of the p53 mRNA and protein, that is abolished by ABT-702, but not by knocking-down A3 adenosine receptor. Adenosine-induced apoptosis in NCI-H28 cells was significantly inhibited by knocking-down p53 and in part by knocking-down A3 adenosine receptor.

      Conclusion
      The results of the present study show that AMP converted from intracellularly transported adenosine upregulates p53 expression to induce caspase-independent apoptosis in malignant pleural mesothelioma cells and that A3 adenosine receptor also participates partially in the apoptosis by the different mechanism.

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    P3.01 - Poster Session 3 - Cancer Biology (ID 147)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P3.01-021 - A3 Adenosine Receptor-Mediated p53- Dependent Apoptosis in Lu-65 Human Lung Cancer Cells (ID 1208)

      09:30 - 16:30  |  Author(s): R. Maeda

      • Abstract

      Background
      A3 adenosine receptor mediates apoptosis in cancer cells via diverse signaling pathways. The present study examined A3 adenosine receptor-mediated apoptosis in Lu-65 cells, a human giant cell lung carcinoma cell line.

      Methods
      MTT assay, TUNEL staining, real-time RT-PCR, Western blotting, and assay of caspase-3, -8, and -9 activities were carried out in Lu-65 cells, and A3 adenosine receptor or p53 was knocked-down by transfecting each siRNA into cells.

      Results
      Extracellular adenosine induces Lu-65 cell apoptosis in a concentration (0.01-10 mM)-dependent manner, and the effect was inhibited by the A3 adenosine receptor inhibitor MRS1191 or by knocking-down A3 adenosine receptor or p53. Like adenosine, the A3 adenosine receptor agonist 2-Cl-IB-MECA also induced Lu-65 cell apoptosis. Adenosine upregulated expression of p53 and Noxa mRNAs and activated caspase-3 and -9, but not caspase-8. Those adenosine effects were still inhibited by knocking- down A3 adenosine receptor or p53.

      Conclusion
      The results of the present study show that adenosine upregulates p53 expression via A3 adenosine receptor, to promote p53-dependent Noxa gene transcription, causing activation of caspase-9 and the effector caspase-3 to induce Lu-65 cell apoptosis.