88P - Biology of plasmacytoid dendritic cells in head and neck cancer (88P)

Date 08 December 2017
Event ESMO Immuno-Oncology Congress 2017
Session Lunch & Poster Display session
Topics Anti-Cancer Agents & Biologic Therapy
Drug Development
Bioethics, Legal, and Economic Issues
Presenter Vladimír Koucký
Citation Annals of Oncology (2017) 28 (suppl_11): xi6-xi29. 10.1093/annonc/mdx711
Authors V. Koucký1, K. Hladíková2, S. Partlová1, J. Bouček3, M. Zábrodský3, A. Fialová1
  • 1Sotio, Sotio, 17000 - Prague/CZ
  • 2Sotio, Sotio, Prague/CZ
  • 3Department Of Otorhinolaryngology And Head And Neck Surgery, 1st Faculty of Medicine, Charles University and Motol University Hospital, Prague/CZ

Abstract

Background

Plasmacytoid dendritic cells (pDC) are the most important IFN type I producing cells. They are studied in context of many malignancies and data show their negative effect on patient prognosis in breast, ovarian, skin and oral cancer. It is assumed, that tumor infiltrating pDC are dysfunctional and support immunosuppressive environment in comparison to blood derived cells. Hence, there is only a few data on functional state of pDC in head and neck cancer (HNSCC).

Methods

Single cell suspensions derived from tumor tissue and PBMC were analysed by flow cytometry. Cytokine levels in cell culture supernatants were detected using Luminex (IFNa, IFNg, IL-10, IL-17a, IL-3, IL-4, IL-6, TNFa). Plasmacytoid DCs were identified as CD45+, Lineage -, CD4+, BDCA2+, CD123+ cells.

Results

We detected higher number of IFNa+ pDC using intracellular staining after Imiquimod stimulation in comparison to CpG (tumor: 18.6% vs. 1.9%, PBMC: 6.2% vs. 2.6%). However, there were higher levels of IFNa in cell culture supernatants after CpG stimulation (tumor: 722.1 vs 208.3 pg/ml, PBMC: 590.8 vs. 23.3 pg/ml). Moreover we found, that IFNa production is highly dependent on a delay between collecting and processing of samples. There was decrease in number of IFNa+ pDC when measured 5h (IMQ: 72.2%, CpG: 53%) and 10h after collection (IMQ: 97.9%, CpG: 84.5%) in healthy controls. The decrease was bigger in samples stored at room temperature. Also, we observed difference when comparing blood samples collected before and after surgery. Non-oncology patients showed stronger reaction to stimulation in samples collected after surgery (IMQ: 13.6% vs 10% IFNa+ pDC, CpG: 6.5% vs 3.2% IFNa+ pDC). On the contrary, preoperative samples of oncology patients showed high number of IFNa+ pDC even in unstimulated cultures. After surgery we observed decrease especially in unstimulated (90.6%) and IMQ stimulated cells (69.2%).

Conclusions

Plasmacytoid DCs might play an important role in regulation of tumor microenvironment in patients with HNSCC. Our data confirm that functionality of pDC is highly dependent on time spent ex vivo. Indeed, there are factors during sample processing which can significantly influence data analysis and so the precise standardization of working protocols is crucial.

Clinical trial identification

Legal entity responsible for the study

Sotio

Funding

Sotio

Disclosure

All authors have declared no conflicts of interest.