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Fernando Souza-Fonseca Guimaraes



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    FP10 - Small Cell Lung Cancer/NET (ID 231)

    • Event: WCLC 2020
    • Type: Posters (Featured)
    • Track: Small Cell Lung Cancer/NET
    • Presentations: 1
    • Moderators:
    • Coordinates: 1/28/2021, 00:00 - 00:00, ePoster Hall
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      FP10.02 - Investigating the Immunophenotype of Small Cell Lung Cancer to Improve Immunotherapeutic Targeting (ID 1686)

      00:00 - 00:00  |  Author(s): Fernando Souza-Fonseca Guimaraes

      • Abstract
      • Presentation
      • Slides

      Introduction

      Small cell lung cancer (SCLC) is the most aggressive subtype of lung cancer and although most patients initially respond to platinum-based chemotherapy, resistance rapidly develops. Immunotherapy has promise in the treatment of lung cancer, however SCLC patients exhibit poor overall responses. This highlights the necessity for alternative treatment approaches. Recently, SCLC has been divided into four subtypes based on the expression of key transcription factors, ASCL1, NEUROD1, POU2F3 and YAP1. Though it has been speculated that these subtypes may respond differentially to therapeutic interventions, response to cytotoxic immune cell killing has not been investigated.

      Methods

      We have investigated the immune microenvironment (IM) profiles of human SCLC patients on freshly obtained endobronchial ultrasound biopsies. We characterized the IM through antibody panels (flow cytometry) and unbiased hierarchal clustering (single-cell sequencing). Immune cell signatures were also interrogated in publicly available human SCLC datasets. Subcutaneous transplantation studies utilizing syngeneic SCLC cell lines were performed to functionally validate the role of cytotoxic immune cell populations. Tumor growth, metastatic dissemination and the activation of CD8+ T and natural killer (NK) cells were evaluated by histology and flow cytometry.

      Results

      Transcriptomic analysis of treatment naïve human SCLC samples revealed heterogeneous immune checkpoint and cytotoxic signature profiles. We identified that immune cell infiltration scores stratified the four subtypes of SCLC, suggesting immunotherapeutic targeting may be prognostic in some patient cohorts. To functionally evaluate the role of cytotoxic immune cells in the surveillance of SCLC, we demonstrated that the absence of NK cells, but not CD8+ T cells, significantly enhanced metastatic dissemination of SCLC in vivo.

      Conclusion

      These proof-of-principle findings provide a rationale for exploiting the anti-tumor functions of NK cells in the treatment of SCLC patients. Critically, the distinct IM profiles of SCLC subtypes reveal an unappreciated level of heterogeneity that warrants further investigation in the stratification of patients for immunotherapy.

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    MA13 - Tumor Biology: Focus on EGFR Mutation, DNA Repair and Tumor Microenvironment (ID 214)

    • Event: WCLC 2020
    • Type: Mini Oral
    • Track: Tumor Biology and Systems Biology - Basic and Translational Science
    • Presentations: 1
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      MA13.04 - Harnessing Natural Killer Cells to Treat Metastatic Small Cell Lung Cancer (ID 1641)

      16:45 - 17:45  |  Author(s): Fernando Souza-Fonseca Guimaraes

      • Abstract
      • Slides

      Introduction

      Small cell lung cancer (SCLC) is the most aggressive subtype of lung cancer, characterized by early metastatic spread. Though most patients initially respond to platinum-based chemotherapy, resistance rapidly develops. Recently, T cell based immune checkpoint blockade (ICB) therapy has rejuvenated first-line treatment of SCLC, however patients inevitably exhibit poor overall responses, highlighting the necessity for alternative therapeutic approaches. Natural killer (NK) cells are an innate cytotoxic immune cell type and emerging alternative to T cell-based immunotherapies. NK cells do not require sensitization to antigens presented on the surface of tumor cells, overcoming the limitations of T cell based ICB.

      Methods

      To investigate immune cell control of metastatic SCLC spread, we utilized a transplantation model of p53Δ/Δ/Rb1Δ/Δ SCLC in recipient mice with modulated immune function. Intravenous injection of the p53Δ/Δ/Rb1Δ/Δ cell line RP-116 results in dissemination to the liver, the primary metastatic site of p53Δ/Δ/Rb1Δ/Δ spontaneous lung tumors and a key metastatic site of patient SCLC metastasis. We investigated the metastatic dissemination of RP-116 in mice deplete of CD8+ T cells and NK cells to identify the key cytotoxic mediator of SCLC.

      Results

      Utilizing sophisticated genetically engineered mouse models, we demonstrated that the absence of NK cells, but not CD8+ T cells, significantly enhanced metastatic dissemination of SCLC tumor cells in vivo. Moreover, hyperactivation of NK cell activity through augmentation of IL-15 or TGF-b signaling pathways ameliorated SCLC metastases, an effect which was further enhanced when combined with anti-PD1 therapy.

      Conclusion

      Our proof-of-principle findings provide a rationale for exploiting the anti-tumor functions of NK cells as a novel therapeutic target in the treatment of SCLC.

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