A novel humanized immune stroma PDX cancer model for therapeutic studies

Dongli Yang1,2, Ian Beddows3, Huijuan Tang1

  • 1Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, UPMC Hillman Cancer Center and the Magee-Womens Research Institute, University of Pittsburgh, Pittsburgh, PA, USA.

Insights

New human stroma-patient-derived xenograft (HS-PDX) models incorporate human tumor stroma, improving preclinical testing. These models better predict patient response to therapies, including immunotherapies, by reflecting stroma

Area of Science:

  • Oncology
  • Preclinical Cancer Models
  • Drug Discovery

Background:

  • Standard preclinical human tumor models lack human tumor stroma, a key component influencing therapeutic resistance.
  • This deficiency may limit the stringency and predictive power of current models for novel cancer therapies.

Purpose of the Study:

  • To develop an advanced preclinical tumor model that incorporates human tumor stroma for more accurate drug testing.
  • To evaluate the utility of this new model in predicting patient response to targeted therapy, chemotherapy, and immunotherapy.

Main Methods:

  • Creation of human stroma-patient-derived xenograft (HS-PDX) models using patient-derived tumor cells, cancer-associated mesenchymal stem/progenitor cells, and human endothelial cells.
  • Development of humanized immune stroma-patient-derived xenograft (HIS-PDX) models by engrafting HS-PDX in mice with humanized bone marrow.
  • Comparative analysis of HS-PDX and standard PDX models regarding therapeutic resistance and patient response correlation.
  • RNA sequencing to assess genomic correlation between HIS-PDX models and primary human tumors.
  • Investigation of the impact of human tumor stroma on immune cell infiltration (e.g., TAMs) and response to immunotherapies.

Main Results:

  • HS-PDX models exhibited greater resistance to targeted therapy and chemotherapy compared to standard PDX models.
  • HS-PDX models demonstrated a higher correlation with patient responses to therapy.
  • HIS-PDX models successfully incorporated human connective tissues, vascular components, and immune cell infiltrates, showing 94-96% RNA sequencing correlation with primary human tumors.
  • Human tumor stroma was shown to influence the recruitment of tumor-associated macrophages (TAMs) and promote tumor immune exclusion, impacting immunotherapy response.
  • A significant immunosuppressive role of human tumor stroma was identified, highlighting its potential to be targeted by immunotherapeutic combinations.

Conclusions:

  • The developed HS-PDX and HIS-PDX models accurately recapitulate the human tumor microenvironment, including stroma and immune components.
  • These advanced models are crucial for preclinical drug testing, offering improved prediction of therapeutic efficacy and patient outcomes.
  • The HIS-PDX model serves as a valuable tool for identifying novel immunotherapeutic strategies to overcome stroma-mediated immunosuppression in cancer.

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