Leukemia Inhibitory Factor-Mediated Immune Modulation in Oral Squamous Cell Carcinomas(2/3)

The progression of OSCC is profoundly affected by a delicate interacting network consisting of cancer cells, infiltrating immune cells, and microenvironmental factors such as the infection of human papillomavirus. Emerging evidences indicate that leukemia inhibitory factor (LIF) plays a critical role in facilitating cancer progression by promoting tumor growth and resistance to anti-cancer therapy. Nevertheless, few studies have been conducted to elucidate the functional role of LIF in OSCC progression or the LIF-mediated immune modulations in OSCC tumor microenvironment. We analyzed the TCGA NGS database and found that higher LIF expression was correlated with a poorer overall survival in OSCC patients. Expression of LIF was associated with functions of the T cell signaling, interferon signaling, and epithelial-mesenchymal transition (EMT) based on results of gene-set enrichment analysis (GSEA). IHC data showed that approximately 30 % (11/35) of OSCC cases we investigated exhibited medium to high infiltration of LIF+-immune cells. LIF might also play a role in the immune modulation of cancer cells. Our data demonstrated that higher LIF expression in cancer cells would suppress expression of key antigen presentation molecules. Using t-SNE and heap map analyses on single cell RNA sequencing data of paired-OSCC samples, we found distinct clonal types of immune cells distributed within OSCC microenvironment. Overall, an immunosuppressive immune phenotype was observed compared to cells derived from adjacent normal tissue. In this project, we combine the oligonucleotide-barcoded surface antibodies, the 3’-single-cell RNA sequencing, and 5’-V(D)J expression technology to investigate the dynamic changes of immune repertoires with more focus on how LIF modulates immune responses within the microenvironment of OSCC. Systemic analyses of single cell RNA sequencing on 20-paired OSCC samples are utilized to obtain insights of OSCC microenvironment and the roles of LIF in immune regulation, followed by strict validations and functional/mechanistic studies. Specific aims include: (1) determine the clinical relevance of LIF expression in oral cancer cells and tumor infiltrating immune cells; (2) determine the profiles of 3’-single cell transcriptome and 5’V(D)J expression in cells derived from OSCC tissues; (3) investigate whether LIF regulates TILs/macrophage polarization in OSCC microenvironment; (4) establish a set of immune marker panel for predicting therapeutic response and evaluate the predictive power on OSCC diagnosis/prognosis; (5) evaluate the potential benefits by targeting to LIF or combining LIF inhibitors in both in vitro and in vivo models; (6) isolate clonal T cells that recognize LIF or selected neoantigens. As we gain a greater understanding of factors in modulating OSCC tumor microenvironment, we should be able to tailor therapeutic strategies by converting the immunosuppressive microenvironment for a selected OSCC patients.