Effects of hypoxia on antigen presentation and T cell-based immune recognition of HPV16-transformed cells

ABSTRACT: Attempts to develop a therapeutic vaccine against human papillomavirus (HPV)-induced malignancies have not been clinically successful to date. One reason may be the hypoxic microenvironment present in most tumors, including cervical cancer. Hypoxia dysregulates the levels of human leukocyte antigen (HLA) class I molecules in different tumor entities, impacts function of cytotoxic T cells, and leads to decreased protein levels of the oncoproteins E6 and E7 in HPV-transformed cells. Therefore, we investigated the effect of hypoxia on the presentation of HPV16 E6- and E7-derived epitopes in cervical cancer cells and its effect on epitope-specific T cell cytotoxicity. Hypoxia induced downregulation of E7 protein levels in all analyzed cell lines, as assessed by Western blotting. However, contrary to previous reports, no perturbation of antigen presentation machinery (APM) components and HLA-A2 surface expression upon hypoxia treatment was detected by mass spectrometry and flow cytometry, respectively. Cytotoxicity assays performed in hypoxic conditions showed differential effects on the specific killing of HPV16-positive cervical cancer cells by epitope-specific CD8+ T cell lines in a donor- and peptide-specific manner. Effects of hypoxia on the expression of PD-L1 were ruled out by flow cytometry analysis. Altogether, our results suggest an intact APM, and cytotoxicity despite the decreased expression of E6 and E7, suggesting that successful immunotherapies can be developed for HPV-induced cervical cancer, especially if combined with hypoxia-alleviating measures.

INSTRUMENT(S): Thermo Scientific instrument model

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Sophia Foehr  

LAB HEAD: Angelika Riemer

PROVIDER: PXD032217 | Pride | 2022-11-16

REPOSITORIES: Pride