Author of

• 17783

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  P2.05 - Poster Session with Presenters Present (ID 463)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Radiotherapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 17785

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    P2.05-002 - CACNA2D1 Enhances Radio-Resistance in Cancer Stem-Like Cells in NSCLC (ID 4991)

    14:30 - 14:30  |  Author(s): G. Zhu
    • Abstract

    Background:
    Radiotherapy is one of the major treatment methods for patients with non-small cell lung cancer (NSCLC). However the presence of radio-resistant cancer stem cells (CSC) may attribute to the relapse or poor outcome of radiotherapy. We previously identified calcium channel α2δ1 subunit (CACNA2D1) isoform 5 as a marker for CSC in hepatocellular carcinoma. This study aimed to investigate the radio-sensitivity of CACNA2D1+ cells in NSCLC cell lines.
    
    Methods:
    NSCLC cell lines A549, H1975 and PC9 were used. CACNA2D1-knockdown or overexpression cell lines were established by lentivirus infection. The proportion of CACNA2D1+ cells before and after radiation was analyzed by flow cytometry. Colony formation assay was performed to determine the radiosensitivity. Sphere formation assay in serum-free medium was performed to evaluate the self-renewal capacity. γH2AX foci were analyzed by immunofluorescence. The monoclonal antibody of CACNA2D1 was applied alone or combined with radiation to CACNA2D1+ cells and colony formation and sphere formation assays were performed to determine its effect on CACNA2D1+ cells.
    
    Results:
    CACNA2D1+ cells had higher sphere-forming efficiency, and were resistant to radiation compared with CACNA2D1- cells. In unsorted cells the CACNA2D1+ percentage was enhanced after radiation. These data suggest CACNA2D1+ NSCLC cells are relatively radio-resistant. Knockdown of CACNA2D1 in CACNA2D1-high A549 enhanced radiosensitivity, while overexpression of CACNA2D1 in CACNA2D1-low PC9 and H1975 reduced radiosensitivity, suggesting CACNA2D1 converts the radio-resistance. The number of γH2AX foci increased after radiation, and decreased more rapidly in CACNA2D1-overexpression cells than control group. Moreover, in CACNA2D1-overexpression cells, the baseline phosphorylation level of CHK2 and ATM was higher than control group, and were more activated after radiation, suggesting CACNA2D1 overexpression resulted in an increase in the DNA damage repair capacity. The monoclonal antibody of CACNA2D1 had a synergetic effect with radiation to block self-renewal of CACNA2D1+ A549 cells. The antibody also enhanced radiosensitivity in CACNA2D1+ cells in colony formation assay.
    
    Conclusion:
    CACNA2D1 marks radio-resistant cancer stem-like cells in NSCLC. CACNA2D1 converts resistance to radiation, partially by enhancing the DNA damage repair efficiency. The monoclonal antibody of CANCA2D1 enhances the radio-sensitivity of CACNA2D1+ cells, suggesting its potential to improve the treatment outcome when combined with radiation on NSCLC.