Reconstituting the head and neck tumor microenvironment with air-liquid interface organoids.

[INTRODUCTION] A patient-derived head and neck cancer organoid (HNCO) model that can reconstruct the tumor-immune microenvironment (TME) was established using air-liquid interface (ALI) culture technology. The Tumor-Infiltrating Lymphocytes (TILs) and cancer-associated fibroblasts (CAFs) could be maintained in this model for a certain period of time. This model was confirmed to simulate PD-1/PD-L1 checkpoint blockade, providing a reliable model for the verification and clinical prediction of the therapeutic effects of relevant immunotherapy drugs for head and neck cancer (HNC).

[METHODS] Fresh tumor tissue samples were obtained to establish an ALI head and neck cancer organoid (ALI-HNCO) model. The oncological characteristics of the organoids and their homology with parental tumors were verified using histomorphological analysis. T lymphocytes and fibroblasts in the organoids were detected using immunofluorescence staining. After treating with pembrolizumab (a PD-1 inhibitor), the secreted levels of the cytokine interferon-γ (IFN-γ) were measured using an enzyme-linked immunosorbent assay (ELISA), and changes in the ratio of CD8+/CD4+ distributed in the immune microenvironment of the organoid, as well as the expression of CD69+ immune cell subsets, were analyzed using flow cytometry. The FVS staining assay was used to verify the killing of tumor cells by cytotoxic T cells.

[RESULTS] The comparison of immunofluorescence in organoids and parental tumor tissues showed that CD3+ lymphocytes and SMA+ cells were also present in the active organoid tissues. Approximately 17.86% (5/28) of the ALI-HNCO model could amplify specific reactive CD8+ T lymphocytes, generating tumor specificity and cytotoxicity.

[DISCUSSION] An HNC immune microenvironment model was successfully constructed using the ALI method. This model maintained the proportions and structures of the components of the original tumor, such as tumor-infiltrating lymphocytes and cancer-associated fibroblasts, for a period of time , providing an experimental platform for exploring the complex crosstalk between HNC cells and multiple cell colonies. This study preliminarily validated the feasibility of using ALI organoid models to evaluate the efficacy of immunotherapy drugs in treating HNC, providing a reliable and stable preclinical model, and new ideas for drug screening platforms for personalized precision medicine in HNC.