Breast Cancer Cell-Derived Adenosine Enhances Generation and Suppressor Function of Human Adaptive Regulatory T Cells

Magis Mandapathil; Miroslaw J Szczepanski; Edwin K Jackson; Stephan Lang; Theresa L Whiteside

doi:10.3390/jpm11080754

Breast Cancer Cell-Derived Adenosine Enhances Generation and Suppressor Function of Human Adaptive Regulatory T Cells

J Pers Med. 2021 Jul 30;11(8):754. doi: 10.3390/jpm11080754.

Authors

Magis Mandapathil^{1

2}, Miroslaw J Szczepanski³, Edwin K Jackson⁴, Stephan Lang⁵, Theresa L Whiteside⁶

Affiliations

¹ Department of Otorhinolaryngology, Asklepios Clinic St. Georg, 20099 Hamburg, Germany.
² Department of Otorhinolaryngol Head & Neck Surg, Philipps University of Marburg, 35033 Marburg, Germany.
³ Department of Biochemistry, Medical University of Warsaw, PL-02097 Warsaw, Poland.
⁴ Department of Pharmacology, University of Pittsburgh, Pittsburgh, PA 15219, USA.
⁵ Department of Otorhinolaryngology, University of Duisburg-Essen, 45147 Essen, Germany.
⁶ UPMC Hillman Cancer Center, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.

Abstract

Introduction: Adaptive regulatory T cells (Tr1) are induced in the periphery by environmental stimuli. CD73 expression and adenosine (ADO) production by tumor cells may influence Tr1 generation and their immunosuppressive activity.

Material and methods: Tr1 were generated in co-cultures of CD4+CD25neg T cells, autologous immature dendritic cells (iDC), and irradiated ADO-producing CD73+ or non-producing CD73neg breast cancer (BrCa) cell lines (TU). The expression of ectonucleotidases and other surface markers on Tr1 was determined by flow cytometry. Tr1-mediated suppression of proliferation was evaluated in CFSE-based assays. Luciferase-based ATP detection assays and mass spectrometry were used to measure ATP hydrolysis and ADO levels. Cytokine levels were measured by ELISA or Luminex. CD73 expression on tumor cells or T cells in TU tissues was assessed by immunofluorescence.

Results: CD73+ TU induced higher numbers of Tr1 cells (p < 0.01) than CD73neg TU. Tr1TU73+ hydrolyzed more exogenous ATP, produced more ADO, and mediated higher suppression than Tr1TU73neg (p < 0.05 for all). ARL67156, an ectonucleotidase inhibitor, and ZM241385, A2A receptor antagonist, reduced suppression of proliferation mediated by Tr1TU73+ cells (p < 0.01). Basal-like primary BrCa cells expressed higher levels of ectonucleotidases and induced more Tr1 than less aggressive primary luminal-like BrCa.

Conclusion: BrCa producing ADO (CD73+ TU) favor the induction of Tr1, which expresses CD39 and CD73, hydrolyzes ATP to ADO, and effectively suppresses anti-tumor immunity.

Keywords: CD73; Treg; adenosine; breast cancer (BrCa); immunosuppression.

Abstract

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