Beyond PD-L1-Identification of Further Potential Therapeutic Targets in Oral Cancer

Manuel Weber; Rainer Lutz; Manuel Olmos; Jacek Glajzer; Christoph Baran; Christopher-Philipp Nobis; Tobias Möst; Markus Eckstein; Marco Kesting; Jutta Ries

doi:10.3390/cancers14071812

Beyond PD-L1-Identification of Further Potential Therapeutic Targets in Oral Cancer

Cancers (Basel). 2022 Apr 2;14(7):1812. doi: 10.3390/cancers14071812.

Authors

Manuel Weber^{1

2}, Rainer Lutz^{1

2}, Manuel Olmos^{1

2}, Jacek Glajzer^{1

2}, Christoph Baran^{1

2}, Christopher-Philipp Nobis^{1

2}, Tobias Möst^{1

2}, Markus Eckstein³, Marco Kesting^{1

2}, Jutta Ries^{1

2}

Affiliations

¹ Department of Oral and Maxillofacial Surgery, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany.
² Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany.
³ Institute of Pathology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany.

Abstract

Background: The involvement of immune cell infiltration and immune regulation in the progression of oral squamous cell carcinoma (OSCC) is shown. Anti-PD-1 therapy is approved for the treatment of advanced OSCC cases, but not all patients respond to immune checkpoint inhibitors. Hence, further targets for therapeutic approaches are needed. The number of identified cellular receptors with immune checkpoint function is constantly increasing. This study aimed to perform a comparative analysis of a large number of immune checkpoints in OSCC in order to identify possible targets for therapeutic application.

Materials and methods: A NanoString mRNA analysis was performed to assess the expression levels of 21 immune regulatory checkpoint molecules in OSCC tissue (n = 98) and healthy oral mucosa (NOM; n = 41). The expression rates were compared between the two groups, and their association with prognostic parameters was determined. Additionally, relevant correlations between the expression levels of different checkpoints were examined.

Results: In OSCC tissue, significantly increased expression of CD115, CD163, CD68, CD86, CD96, GITRL, CD28 and PD-L1 was detected. Additionally, a marginally significant increase in CD8 expression was observed. BTLA and PD-1 levels were substantially increased, but the differential expression was not statistically significant. The expression of CD137L was significantly downregulated in OSCC compared to NOM. Correlations between immune checkpoint expression levels were demonstrated, and some occurred specifically in OSCC tissue.

Conclusions: The upregulation of inhibitory receptors and ligands and the downregulation of activators could contribute to reduced effector T-cell function and could induce local immunosuppression in OSCC. Increased expression of activating actors of the immune system could be explained by the increased infiltration of myeloid cells and T-cells in OSCC tissue. The analysis contributes to the understanding of immune escape in OSCC and reveals potential targets for oral cancer immunotherapy.

Keywords: HNSCC; MDSC; OSCC; T-cell; head and neck cancer; immune checkpoints; immunotherapy; macrophage.