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R. Puri

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    O08 - Preclinical Therapeutic Models I (ID 92)

    • Event: WCLC 2013
    • Type: Oral Abstract Session
    • Track: Biology
    • Presentations: 1
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      O08.01 - A novel autophagosome non-small cell lung cancer vaccine (DRibbles) contains short-lived proteins, defective ribosomal products, at least nine NCI-prioritized antigens, and agonists for TLR 2, 3, 4, 7, and 9. (ID 2612)

      16:15 - 17:45  |  Author(s): R. Puri

      • Abstract
      • Presentation
      • Slides

      Tumor-derived autophagosomes, referred to as DRibbles, are novel cancer vaccines that have been shown to be effective against 5 preclinical models of established tumors. We hypothesize that DRibbles’ efficacy stems from their ability to present stabilized tumor-derived short-lived proteins (SLiPs) and defective ribosomal products (DRiPs) that are, due to their short-lived nature, normally not processed and presented by professional antigen presenting cells. These SLiPs and DRiPs represent a potential pool of tumor antigens against which the host is not tolerant. A pilot clinical trial of an autologous DRibble vaccine demonstrated feasibility and suggested immune effects in 4 patients with advanced NSCLC (WCLC 2013, submitted). In order to expand the DRibble strategy to patients without an autologous tumor source, we have produced an allogeneic DRibble vaccine (DPV-001) from two NSCLC cell lines and developed a panel of 13 NSCLC cell lines expressing relevant antigenic targets that will be used to monitor induction of tumor-specific immunity.

      The two NSCLC cell lines used to produce the DPV-001 vaccine (UbiLT3 and 6) were cultured with bortezomib and ammonium chloride to block the proteasome and prevent lysosomal degradation of SLiPs and DRiPs. Gene expression profiles were performed for each lot produced (Human Gene 1.0 ST arrays). Stability of indicator tumor antigens was assessed by Western blots. Toll-like receptor (TLR) agonist activity was assessed using HEK blue cells transfected with specific TLRs. After informed consent, a panel of NSCLC cell lines was established from 13 patients (tumor tissue or pleural fluid). These cell lines were HLA-typed for use in immunologic monitoring studies. cDNA was synthesized in triplicate from total RNA extracted from each cell line in log phase growth. Samples were then analyzed using human microarrays containing approximately 17,000 oligonucleotides (CBER array). Data files were uploaded into the mAdb database and analyzed by software provided by the Center for Information Technology (CIT), NIH. Group t-test was used to compare gene expression differences between NSCLC and normal lung tissues and between cell lines.

      Analyses confirm reproducible gene expression profiles from both cell lines during DPV-001 manufacture, and stability studies demonstrate that the vaccine remains stable for 23 months. The vaccine contains at least nine NCI-prioritized cancer antigens and agonists for 5 TLRs. Gene expression profiles of the 13 NSCLC cell lines identified 46 commonly overexpressed genes, all of which are expressed in the DPV-001 vaccine.

      The DPV-001 vaccine provides a source of broad-spectrum relevant NSCLC antigens. We are conducting a multicenter, randomized, phase II trial of adjuvant DPV-001 vaccine in patients with definitively treated stage IIIA/B NSCLC. T-cell immune responses will be monitored using HLA matched cell lines from the indicator panel of 13 NSCLC cell lines. NIH grants R21 CA123864 (WJU) and R43/44 CA121612 (SA, TH), Kuni Foundation (WJU), Murdoch Trust, Robert Franz, Wes and Nancy Lematta, Lyn and Jack Loacker, and the Chiles Foundation. study identifier pending

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