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Bile acids restrict functional reprogramming of myeloid-derived suppressor cells in tumor beds

胆汁酸限制肿瘤床中骨髓源性抑制细胞的功能重编程

基本信息

批准号：
10482381
负责人：
Paulo Cesar Rodriguez
金额：
$ 36.92万
依托单位：
H. LEE MOFFITT CANCER CTR & RES INST
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-15 至 2026-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10482381
关键词：
Automobile Driving Beds Bile Acids Cell physiology Cells Cholesterol Cholesterol Homeostasis Chronic Development Effectiveness Endoplasmic Reticulum Foundations Goals Human Immune Immune checkpoint inhibitor Immunity Immunosuppression Immunotherapy In Situ Individual Interferons Intestines Knockout Mice Link Liver Liver Regeneration Malignant Neoplasms Mediating Mediator of activation protein Metabolic Modeling Mus Myeloid Cells Myeloid-derived suppressor cells Myelopoiesis Phosphotransferases Proteins Publications Reaction Receptor Activation Receptor Signaling Regulation Role STAT1 gene Signal Transduction T cell response T-Lymphocyte Testing Therapeutic Transplantation Tumor Immunity Tumor Markers Tumor-infiltrating immune cells XBP1 gene anticancer treatment base cancer immunotherapy cell transformation checkpoint therapy endoplasmic reticulum stress gut inflammation immunogenic in vivo insight novel strategies novel therapeutic intervention protein folding receptor response success therapeutically effective transcription factor tumor tumor growth tumor microenvironment type I interferon receptor uptake

项目摘要

ABSTRACT The expansion of myeloid-derived suppressor cells (MDSC) in tumor-bearing hosts has emerged as a primary mechanism to limit protective anti-tumor T cell responses and a major obstacle to the success of cancer immunotherapy. It is therefore imperative to develop new effective therapeutic strategies to overcome the immune restricting effects induced by MDSC in tumors. Our recent studies demonstrated that MDSC chronically activate an integrated signaling network known as the unfolded protein responses (UPR) as a reaction to the sustained and pronounced endoplasmic reticulum (ER) stress induced by the precarious conditions of the tumor microenvironment (TME). Also, conditional deletion of the UPR-related PKR-like ER kinase (PERK) functionally reprogrammed MDSC into immunostimulatory cells that partially restore protective anti-tumor immunity in tumor beds. Importantly, our new Preliminary Results demonstrate a compensatory accumulation of highly immune- regulatory primary and secondary bile acids (BAs) in PERK-ablated MDSC in tumors. BAs are synthetized in the liver and intestine as final products of cholesterol metabolism and signal through priming of farnesoid X receptor (FXR) transcription factor, which was found increased in PERK-null MDSC and augmented MDSC suppressive activity. Based on these crucial findings, we hypothesize that the accumulation of intracellular BAs restricts the transformation of PERK-null MDSC in tumors into myeloid cells that promote sustained protective T cell immunity through activation of FXR and a subsequent induction of the compensatory UPR mediators, IRE1→Xbp1. We also propose that inhibition of PERK plus IRE1 will completely overcome MDSC-linked suppression in tumors and synergize with T cell and checkpoint immunotherapies. We propose the following Specific Aims: In Aim 1, we will determine the restrictive action of the accumulated BAs in the functional transformation of PERK-null MDSC into myeloid cells that prime sustained protective anti-tumor T cell immunity. In Aim 2, we will elucidate the mechanisms whereby BAs restrict PERKKO MDSC transformation in tumors. In Aim 3, we will test the prediction that combined inhibition of PERK and IRE1 completely overcomes MDSC- associated immunosuppression and enhances the effectiveness of cancer immunotherapy. The metabolic mediators driving the immunosuppressive functionality of MDSC in tumor beds remain poorly described. Thus, development of the Aims will have a profound impact on the field by substantiating a major metabolic signal whereby tumors restrict the functional transformation of MDSC after targeting the ER stress mediator, PERK. Also, our proposal will provide a mechanistic rationale for the development of novel therapeutic approaches to entirely reprogram immunosuppressive myelopoiesis in tumor-bearing hosts, which is likely to synergize with cancer immunotherapy and provide new biomarkers for tumor-MDSC reprogramming.

摘要