Chemotherapy Induces Pancreatic Cancer Organoid Immune Evasion by Upregulating Programmed Death Ligand 1
Authors: Holokai Loryn , Chakrabarti Jayati , Chang Julie , Lanfranca Mirna Perusina , Wang Jiang , Frankel Timothy , Ahmad Syed , Zavros Yana 
Published: June 2021

Background

Pancreatic Ductal Adenocarcinoma (PDAC) has a 5‐year survival rate of only 8%. This is due to the lack of targeted therapies and a poor response to chemotherapeutics. PDAC cells evade the immune response by expressing programmed death ligand 1 (PD‐L1), which is able to inhibit cytotoxic T lymphocyte (CTL) proliferation and effector function. Currently, there are no reliable preclinical models that allow us to test the efficacy of chemotherapeutics or PD‐L1 inhibitors. This evidence warrants the development of a preclinical model whereby the patient's immune response within the tumor microenvironment is tested prior to therapy.

Hypothesis

Treatment of PDAC‐derived organoids (huTPOs) with chemotherapeutics induces the expression of PD‐L1 leading to increased immune evasion and tumor growth.

Methods

HuTPOs were derived from resected pancreatic tumors of PDAC patients. Conditioned media was collected from cultured huTPOs (huTPOCM). Peripheral blood mononuclear cells (PBMCs) were extracted from autologous patient blood. Dendritic cells (DCs) were cultured in a cytokine cocktail and sorted by flow cytometry for high HLA‐DR expression. CD8+ CTLs were isolated from patient PBMCs using a CD8+ T Cell Enrichment Kit. DCs were then pulsed with huTPOCM for 24 hours and co‐cultured with autologous isolated CTLs for 72 hours. HuTPOs were co‐cultured with autologous‐pulsed DCs and activated CTLs for 24 hours. The cultures were then treated with the chemotherapeutic agent(s) with which the patient was treated, with or without PD‐L1 inhibitor and apoptosis was analyzed by TUNEL assay. In a separate series of experiments, a 72‐hour time course was performed using huTPOs treated with combinations of chemotherapeutics with which the patients were treated.

Results

HuTPOs mimic patient response to chemotherapeutics. HuTPOs exhibited divergent responses to chemotherapeutic agents including FOLFIRNOX (oxaliplatin, leucovorin, irinotecan and 5‐FU) or gemcitabine and abraxane. HuTPO response correlated with the patient's tumor response to similar chemotherapeutic treatment.

HuTPOs express increased PD‐L1 expression following chemotherapy treatment: Following chemotherapy treatment, huTPOs expressed increased PD‐L1 compared to untreated huTPOs. HuTPOs that expressed PD‐L1 were protected from CTL mediated apoptosis in an autologous huTPOs/immune cell co‐culture except when treated with PD‐L1 inhibitor.

Conclusion

The current patient‐derived approach is expected to create a personalized model system that can be used to determine the most efficacious chemotherapeutic treatment as well as response to PD‐L1 inhibitors in PDAC patients.

Support or Funding Information

Steven Goldman Memorial Pancreatic Cancer Research Grant (Zavros) 1RO1DK083402

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.