Author of

• 11515

  +

  P2.05 - Poster Session 2 - Preclinical Models of Therapeutics/Imaging (ID 158)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Biology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 11538

    +

    P2.05-023 - In vivo micro-imaging of apoptosis in a murine xenograft model of human lung adenocarcinoma (ID 3324)

    09:30 - 09:30  |  Author(s): J. Picquenot
    • Abstract

    Background
    Resistance to apoptosis is a hallmark of cancer that can be reversed by several chemotherapy drugs and targeted therapies, including cisplatin and erlotinib. In vivo imaging of apoptosis would be of great interest to study molecular mechanisms of drug activity and resistance. The aim of this study is to investigate whether in vivo micro-imaging of apoptosis could be used for early assessment of treatment response in a murine xenograft model of human lung cancer.

    Methods
    A549 (EGFR wild type), H1650 (carrying EGFR exon 19 deletion that confers sensitivity to Erlotinib) and H1975 (carrying EGFR mutations L858R and T790M, resistant to Erlotinib) cell lines were used to induce subcutaneous tumors in Nude mice. In vivo micro-imaging of apoptosis was performed using fibered confocal fluorescence microscopy (FCFM) after intra-venous injection of a fluorogenic caspase 3 substrate. Tumors were treated by cisplatin (10mg/kg) (5 mice, A549 xenografts), erlotinib (25mg/kg) (6 mice, 2 A549, 2 H1650, 2 H1975), or vehicle (6 mice, 2 A549, 2 H1650, 2 H1975).

    Results
    In A549 xenografts treated by cisplatin, apoptosis was detected in vivo at 24h post-treatment. Fluorescence intensity ratio (FIR) was significantly higher than in untreated tumors (16.9+/-3.1 vs 4.8+/-2.1 respectively, p<0.001). 24h after treatment by erlotinib, FIR in H1650 erlotinib sensitive tumors was significantly higher than in A549 tumors, and than in H1975 erlotinib resistant tumors (12.2+/-2.4 vs 6.1+/-1.2 vs 1.9+/-0.7 respectively, p<0.01, Figures 1 and 2). Results were confirmed ex vivo on harvested tumor xenografts by TUNEL assay and immunohistochemistry for activated caspase 3, and on cell lines in vitro by flow cytometry and fluorescence microscopy. Figure 1 Figure 2

    Conclusion
    Early in vivo micro-imaging of apoptosis using FCFM makes it possible to differentiate sensitive from resistant tumors to Erlotinib in a murine xenograft model of human lung adenocarcinoma.