Mucosal-associated invariant T cells in Hepatocellular Carcinoma

• Applicant: Dr. Simon Wabitsch
• Subject Area: Hematology, Oncology
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 430914934

Hepatocellular carcinoma (HCC) is the second leading cause of cancer related death worldwide in men and sixth leading cause for women. Risk factors for HCC are well defined and include hepatitis B, hepatitis C, metabolic syndrome and alcohol abuse. Recently, immune-checkpoint inhibitors have been successfully applied to treat different cancer types such as melanoma and lung cancer. In case of HCC, several agents are currently under investigation. The tumor microenvironment appears to assume a pivotal role in defining which patients benefit from checkpoint inhibitors and which escape an immune response. Mucosal-associated invariant T cells (MAIT) represent the most dominant population of innate-like T-lymphocytes, comprising nearly 50% of all T-cells in the liver. The semi-invariant T-cell receptor of MAIT cells recognise non-peptide ligands presented by monomorphic MHC-like molecules and has a bridging function between the innate and adaptive immune system. It is suggested that MAIT play an important role in defending the biliary mucosa against ascending infections from the gut. The precise implications of MAITs in tumor development and progression remain to be clarified. MAIT represent only a small subset of T cells in common laboratory strains of mice. In murine livers, invariant NKT cells (iNKT) represent the largest population of innate-like T cells.As part of the NCI -CCR liver cancer program, the research group of Prof. Greten has established a collaboration with Dr. Alexander Kroemer from the center for liver and pancreas surgery of the Georgetown University Hospital. This allows for obtaining fresh tumor tissue from HCC patients. We want to isolate, sort and perform single cell RNA sequencing of MAIT from the core and rim of HCC tissue samples as well as peritumoral control liver tissue and blood of patients. After sorting for MAITs, cells are loaded on the BD rhapsody platform for cDNA library preparation. This platform is designed to perform surface staining of antigens with DNA barcode-labelled beads, giving the opportunity to acquire data about the mRNA levels of a single cell and to obtain data concerning the protein level of the same cell to correlate transcriptomic and protein information.A further line of investigation is intended by using a murine model. Herein, we will use liver-specific MYC oncogene transgenic mice and animals will be treated with different regimes: Placebo and the tested anti-PD-1 checkpoint inhibitor. iNKT cell population and function will be analyzed in control tissue, gut, tumor core and tumor rim as described above. Applying this technique gives us the chance to perform a multidimensional analysis of iNKT cells in the liver of HCC and identify subpopulations and function and their potential in the context of HCC. Ultimately, our study will provide us with a comprehensive understanding of the role of MAIT in HCC, which might play a critical role in immune response regulation.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Tim F. Greten