ABSTRACT
BACKGROUND: Promising outcomes have been observed in multiple myeloma (MM) with the use of immunotherapies, specifically chimeric antigen receptor T (CAR-T) cell therapy. However, a portion of MM patients do not respond to CAR-T therapy, and the reasons for this lack of response remain unclear. The objective of this study was to investigate the impact of miR-34a on the immunosuppressive polarization of macrophages obtained from MM patients. METHODS: The levels of miR-34a and TLR9 (Toll-like receptor 9) were examined in macrophages obtained from both healthy individuals and patients with MM. ELISA was employed to investigate the cytokine profiles of the macrophage samples. Co-culture experiments were conducted to evaluate the immunomodulatory impact of MM-associated macrophages on CAR-T cells. RESULTS: There was an observed suppressed activation of macrophages and CD4+ T lymphocytes in the blood samples of MM patients. Overexpression of miR-34a in MM-associated macrophages dampened the TLR9 expression and impaired the inflammatory polarization. In both the co-culture system and an animal model, MM-associated macrophages suppressed the activity and tumoricidal effect of CAR-T cells in a miR-34a-dependent manner. CONCLUSION: The findings imply that targeting the macrophage miR-34a/TLR9 axis could potentially alleviate the immunosuppression associated with CAR-T therapy in MM patients.
Subject(s)
MicroRNAs , Multiple Myeloma , Signal Transduction , Toll-Like Receptor 9 , Multiple Myeloma/immunology , Multiple Myeloma/genetics , Multiple Myeloma/therapy , Multiple Myeloma/metabolism , MicroRNAs/genetics , Toll-Like Receptor 9/metabolism , Toll-Like Receptor 9/genetics , Humans , Animals , Mice , Coculture Techniques , Tumor-Associated Macrophages/immunology , Tumor-Associated Macrophages/metabolism , Macrophages/immunology , Macrophages/metabolism , Immunotherapy, Adoptive/methods , Male , Female , Macrophage Activation/immunology , Macrophage Activation/genetics , Cell Line, TumorABSTRACT
Multiple myeloma (MM) progression involves diminished tumor antigen presentation and an immunosuppressive microenvironment, characterized by diminished expression of major histocompatibility complexes (MHC) class I molecule and elevated programmed death ligand 1 (PDL1) in MM cells, along with an enriched population of regulatory T cells (Tregs). To investigate Treg's influence on MM cells, we established a co-culture system using Tregs from MM patients and the MM cell lines (MM.1S and SK-MM-1) in vitro and assessed the effects of intervening in the relevant pathways connecting Tregs and MM cells in vivo. In vitro, Tregs induced transforming growth factor beta-1 (TGF-ß1) production, downregulated MHC I members, and increased PDL1 expression in MM cells. Treg-derived TGF-ß1 suppressed the cGAS-STING pathway, contributing to the loss of MHC I molecule expression and PDL1 upregulation. Correspondingly, neutralizing TGF-ß1 or activating the cGAS-STING pathway restored MHC I and PDL1 expression, effectively countering the pro-tumorigenic effect of Tregs on MM cells in vivo. These data elucidated how Tregs influence tumor antigen presentation and immunosuppressive signal in MM cells, potentially providing therapeutic strategies, such as neutralizing TGF-ß1 or activating the cGAS-STING pathway, to address the immune escape and immunosuppressive dynamics in MM.
Subject(s)
B7-H1 Antigen , Histocompatibility Antigens Class I , Membrane Proteins , Multiple Myeloma , Nucleotidyltransferases , Signal Transduction , T-Lymphocytes, Regulatory , Transforming Growth Factor beta1 , Humans , Multiple Myeloma/metabolism , Multiple Myeloma/immunology , Multiple Myeloma/pathology , Multiple Myeloma/genetics , Transforming Growth Factor beta1/metabolism , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , Histocompatibility Antigens Class I/metabolism , Histocompatibility Antigens Class I/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , B7-H1 Antigen/metabolism , B7-H1 Antigen/genetics , Cell Line, Tumor , Animals , Down-Regulation , Mice , Female , Coculture Techniques , Male , Gene Expression Regulation, NeoplasticABSTRACT
OBJECTIVE: To investigate regulatory T cells (Tregs) relative content in peripheral blood and bone marrow of patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) treated with or without decitabine (DAC), analyze the immunomodulatory of Tregs in pathogenesis and remission of MDS and AML, as well as effect of DAC on Tregs. METHODS: From October 2018 to February 2019, 15 patients with MDS and 49 patients with AML (newly diagnosed, treated with DAC or other chemotherapy regimens) were enrolled in this study, and 14 cases with iron deficiency or megaloblastic anemia while without malignant tumor and autoimmune disease as controls. The Tregs relative contents in bone marrow and peripheral blood were analyzed by flow cytometry, meanwhile clinical data of the objects were collected. RESULTS: In peripheral blood and bone marrow of the patients with MDS and AML, the Tregs relative contents at newly diagnosed were higher than those of the control group (P=0.05, P=0.043). The Tregs relative content of AML patients in DAC regimen treatment group was significantly lower than that in the newly diagnosed group and non-DAC chemotherapy group (P<0.05). In DAC regimen treatment group, the Tregs relative contents was significantly lower in remission group than in non-remission group (P<0.05). There was no difference between DAC regimen treatment group and control group in Tregs relative content. CONCLUSION: DAC may increase the body's anti-tumor immunity by consuming Tregs content, enhance the body's immune function to identify and kill tumor cells, thereby promote the patients' reliefs.