Virtual Library

 x 
My Library Virtual Library FAQ

Start Your Search

A. Khong



Author of

  • +

    MINI 24 - Epidemiology, Early Detection, Biology (ID 140)

    • Event: WCLC 2015
    • Type: Mini Oral
    • Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
    • Presentations: 1
    • +

      MINI24.14 - Use of Next Generation Sequencing to Improve Lung Tumor Immunotherapy (ID 1749)

      18:00 - 18:05  |  Author(s): A. Khong

      • Abstract
      • Presentation
      • Slides

      Background:
      Immunotherapy of pulmonary tumors is now a clinical reality, however most patients do not respond. To convert non-responders into responders one potential approach is to identify the tumor‐specific ‘neo‐antigens’ that arise from DNA mutations in order to follow tumor-specific responses and to design therapeutic vaccines to try to ‘enforce’ a response against these resistant tumors.

      Methods:
      First, in order to identify tumor neo-antigens we performed RNAseq and exome analysis to identify single nucleotide variants (SNV) in murine pulmonary tumors. An average of 485 SNVs was found. We focused on AB1 and AB1-HA (asbestos-induced mesotheliomas, which mimic human mesothelioma) and Line 1 (lung cancer). We used the NetMHCpan 2.8 algorithm to identify candidate mutation‐carrying peptides and screened them in an interferon‐γ ELISPOT assay. Second, to determine if more neo-antigens could be ‘unmasked’ by therapy, we tested three candidate therapies in our murine model then reanalyzed neo-antigen responses a) Treg depletion using Foxp3-DTR mice, b) gemcitabine, an immunogenic cytotoxic chemotherapy commonly used for pulmonary malignancies, and c) antiCTLA4 (a checkpoint blockade therapy).

      Results:
      We identified 20 candidate mutation‐carrying peptides in the ELISPOT assay. A strong spontaneous endogenous pre-treatment immune response was demonstrated to DUqcrc2, a component of the respiratory chain protein ubiquinol cytochrome complex. It was found to stimulate a strong response at a similar magnitude to the model neo-antigen viral haemagglutinin (HA). The DUqcrc2 peptide sequence (amino acid 405-413) is predicted to bind the H-2Kd, and the mutant has a proline to alanine substitution mutation at position 408. Treg depletion unmasked a second neo-antigen, DGANAB. GANAB is an alpha glucosidase which cleaves the 2 innermost alpha-1,3-linked glucose residues from the Glc-2-Man-9-GlcNAc-2 oligosaccharide precursor of immature glycoproteins. There is an arginine to glutamine substitution mutation at position 969 of DGANAB (965-972) sequence. This observation supports the theory that removing Treg cells may broaden the immune response to a greater number of neo-antigens, a response presumably otherwise restrained by Treg suppression. Gemcitabine and antiCTLA4 checkpoint blockade did not unmask any additional neo-antigens.

      Conclusion:
      Thus, removing some immune restraints may expose a greater number of neo-antigens as potential clinical targets. The results from these approaches suggest novel ways to improve the immunotherapy of lung tumor and are the basis for planning current clinical trials.

      Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.

      Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.