Vanessa V. Catania

Abstract Mucosal-associated invariant T (MAIT) cells are MR1-restricted innate-like T cells that recognize non-peptide antigens including riboflavin derivates. Although in vitro–activated MAIT cells show antitumor activity, the in vivo role of MAIT cells in cancer is still unclear. Here, we have shown that MAIT cells have antitumor function in vivo when activated by a combination of the synthetic riboflavin synthesis pathway–derived antigen 5-OP-RU [5-(2-oxopropylideneamino)-6-D-ribitylaminouracil] and the Toll-like receptor 9 (TLR9) agonist CpG. Coadministration of 5-OP-RU and CpG induced strong systemic in vivo expansion and activation of MAIT cells with high CD69 expression, pronounced effector memory phenotype, and upregulated levels of effector molecules including IFNγ, granzyme B, and perforin. Activated and expanded MAITs induced a potent and broad antitumor immune response in murine models of liver metastasis and hepatocellular carcinoma, lung metastasis, and subcutaneous tumors in two different mouse strains. Such tumor inhibition was absent in MAIT-deficient Mr1−/− mice. CRISPR/Cas9-mediated MR1 knockout in tumor cells did not affect efficacy of this MAIT-directed immunotherapy, pointing toward an indirect mechanism of action. Our findings suggest that MAIT cells are an attractive target for cancer immunotherapy. See related Spotlight by Lantz, p. 996.

ABSTRACT Glioblastoma, the most common primary brain malignancy, is invariably fatal. Systemic chemotherapy is ineffective mostly because of drug delivery limitations. To overcome this, we devised an internalized pump-catheter system for direct chronic convection-enhanced delivery (CED) into peritumoral brain tissue. Topotecan (TPT) by chronic CED in 5 patients with refractory glioblastoma selectively eliminated tumor cells without toxicity to normal brain. Large, stable drug distribution volumes were non-invasively monitored with MRI of co-infused gadolinium. Analysis of multiple radiographically localized biopsies taken before and after treatment showed a decreased proliferative tumor signature resulting in a shift to a slow-cycling mesenchymal/astrocytic-like population. Tumor microenvironment analysis showed an inflammatory response and preservation of neurons. This novel drug delivery strategy and innovative clinical trial paradigm overcomes current limitations in delivery and treatment response assessment as shown here for glioblastoma and is potentially applicable for other anti-glioma agents as well as other CNS diseases.

Abstract Introduction: Hepatocellular Carcinoma (HCC) is a leading cause of cancer-related death and can be considered a prototype of inflammation-derived cancer arising from chronic liver injury. The cell composition of the HCC tumor immune microenvironment (TiME) has a major impact on cancer biology as the TME can have divergent capacities on tumor initiation, progress, and response to therapy. Recent development of multi-omics and single-cell technologies help us to comprehensively quantify the cellular heterogeneity and spatial organization of the TiME and to further our understanding of antitumor immunity. Methods: Multiplexed immunofluorescence microscopy and high-dimensional flow cytometry was used to analyze immune cell infiltration in primary human liver cancer samples. We developed and validated a comprehensive 37-plex antibody panel for immunofluorescence imaging of human fresh frozen HCC samples. We applied highly multiplexed co-detection by indexing (CODEX) technology to simultaneously profile in situ expression of 37 proteins at sub-cellular resolution in 15 HCC patient samples using whole slide scanning. We established an image analysis pipeline to quantify all major cell populations in the human liver using supervised manual gating and unsupervised clustering algorithms. Proximity and nearest neighbor calculations as well as infiltration analysis was performed using HALO quantitative image analysis software. Results: Using high-dimensional flow cytometry and parallel spatially resolved quantitative analysis of multiplexed immunofluorescence microscopy images, we profiled the single-cell pathology landscape for human HCC. The translation from raw images to numerical output was successfully established. In situ phenotyping of 4,500,000 single cells (including 1,500,000 CD45+ immune cells) allowed for the quantification of cell phenotype clusters, differential analysis of activation markers and spatial features of each individual cell. CODEX imaging revealed detailed composition of the immune cell niche in human liver cancer tissue allowing for further distinct spatial analysis including infiltration analysis and nearest-neighbor analysis. We found impaired infiltration of CD163+ macrophages, granulocytes, CD8+ T cells, NK cells and MAIT cells into human HCC tumors compared to unaffected liver tissue. whereas regulatory T cells accumulated in tumor tissue. Flow cytometry data correlated well with image-based immune phenotyping. Beyond that, whole slide imaging allowed for the identification of the tumor-to-liver interface as a unique site of immune cell inhibition. Conclusion: Here, we demonstrate that spatially resolved, single-cell analysis of human liver cancer tissue allows for the in-depth characterization of the immune cell composition of HCC. This tool can be used for biomarker research, to determine cellular functional states in intact tissue and to spatially and functionally quantify interactions between immune cells in the context of hepatocarcinogenesis. Citation Format: Benjamin Ruf, Noemi Kedei, Matthias Bruhns, Sepideh Babaei, Vanessa V. Catania, Simon Wabitsch, Chi Ma, Bernd Heinrich, Varun Subramanyam, Merrill K. Stovroff, Layla T. Greten, Alexander Kroemer, Manfred Claassen, Tim F. Greten, Firouzeh Korangy. Highly multiplexed spatial analysis of the HCC tumor immune microenvironment using CODEX imaging [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P021.