Author of

• 30844

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  P1.04 - Immuno-oncology (ID 164)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Immuno-oncology
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/08/2019, 09:45 - 18:00, Exhibit Hall

  • 30886

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    P1.04-36 - An in Vivo Inflammatory Loop Potentiates KRAS Blockade (ID 521)

    09:45 - 18:00  |  Presenting Author(s): Kristina Anna Maria Arendt
    • Abstract

    Background
    

    Several reports from different groups suggest that novel KRAS inhibitors are not effective ex vivo, but the mechanism(s) responsible for this are unknown. We performed complex experiments that highlight the huge discrepancy between the marked in vivo and the minimal in vitro effects of KRAS inhibitors. Furthermore, we identified and validated the mechanism of the in vivo-restricted actions of KRAS inhibitors in immunocompetent mice, which can be translated to successful new treatments for patients with KRAS-mutant cancers.

    Method
    

    We treated tumor cells with defined KRAS mutation status with KRAS inhibitors deltarasin, cysmethynil, and AA12 and used different in vitro assays as readout. Additionally KRAS silencing and overexpression were done using shRNA and KRAS^G12C vectors and included in the experimental setup. In parallel C57BL/6 wildtype mice or deficient in interleukin (IL)-1β (Il1b-/-) or chemokine receptors (Ccr2-/-, Cxcr1-/-, Cxcr2+/-) received s.c. KRAS-mutant or wild-type tumor cells followed by saline or deltarasin treatments. Microarrays were done using a large set of Kras-mutant and Kras-wildtype cell lines.

    Result
    

    We identified that KRAS inhibitors exerted comparable effects against cancer cells in vitro irrespective of KRAS status. However, mice only with KRAS-mutant tumors responded selectively to deltarasin treatment. Similar in vivo-restricted effects were evident after genetic manipulation of KRAS. Microarrays identified a 42-gene signature specific to Kras-mutant cancer cells and responsive to Kras manipulation, which contained Kras, Ccl2, Il1r1, Ccl7, and Cxcl1. Deltarasin was effective in halting KRAS-mutant flank tumors in Wt, Cxcr1-/-, and Cxcr2+/-, but not in Ccr2-/- and Il1b-/- mice. qPCR results revealed a strong regulation of Il1r1/IL1R1 mRNA expression depending of Kras/KRAS mutation status and drug treatment. Thereby, KRAS inhibition can be effective in vivo via blockade of the positive feedback loop of KRAS-CCL2-IL1ß.

    Conclusion
    

    Inflammatory signaling loops are synthetic lethality targets for KRAS mutant tumors and only druggable by KRAS inhibitors in vivo. Hence in vitro drug screens may be suboptimal settings for anti-KRAS drug discovery.

• 30780

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  P2.03 - Biology (ID 162)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Biology
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 30830

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    P2.03-48 - Tumor-Derived Granulocyte Chemotactic Protein 2 Cooperates with Proteases to Drive Lung Adenocarcinoma (ID 1326)

    10:15 - 18:15  |  Author(s): Kristina Anna Maria Arendt
    • Abstract

    Background
    

    Introduction: Lung adenocarcinoma (LADC) commonly arises in the lungs of smokers that are heavily affected by chronic inflammation. Inflammatory signaling from tumor to host cells is critically involved in the pathogenesis of LADC, but the exact mechanisms by which the lung epithelium interacts with the immune system during carcinogenesis are obscure.

    Objectives: We discovered that murine and human LADC cell lines overexpress the inflammatory and angiogenic CXC chemokine granulocyte chemotactic protein 2 (GCP2, CXCL6) compared with normal epithelial cells. GCP2 is processed by immune proteases: neutrophil elastase (NE, ELANE), proteinase 3 (PR3, PRTN3) and matrix metalloproteinase 9 (MMP9, MMP9). We suppose that GCP2 interacts with these proteases to drive LADC and aimed at investigating its function(s).

    Method
    

    GCP2, MMP9 and PR3 expressions were determined by ELISA and immunohistochemistry. Mouse and human microarray data were analyzed using Affymetrix Transcriptome Analysis Console. GCP2 silencing using dedicated shRNA pools (SantaCruz Biotechnology) and NE/PR3 or MMP9 compound knockout mice were used to study GCP2 interaction with immune proteases in LADC progression.

    Result
    

    Murine and human LADC tumors and cell lines overexpress GCP2, MMP9, NE and PR3 at the mRNA and protein levels. GCP2 is sequestered to tumor cells, whereas proteases are produced by tumor-infiltrating immune cells. LADC-secreted GCP2 is incompletely processed and require MMP9, NE or PR3 for full activation and vasoactive effects. Moreover, GCP2-silenced LADC cells injected in mice show a lack in metastasis formation.

    Conclusion
    

    Our results indicate that tumor-originated GCP2 cooperates with immune proteases to drive LADC, providing a paradigm of how the respiratory epithelium coopts the innate immune system during carcinogenesis.