ABSTRACT
Recent transcriptomic-based analysis of diffuse large B cell lymphoma (DLBCL) has highlighted the clinical relevance of LN fibroblast and tumor-infiltrating lymphocyte (TIL) signatures within the tumor microenvironment (TME). However, the immunomodulatory role of fibroblasts in lymphoma remains unclear. Here, by studying human and mouse DLBCL-LNs, we identified the presence of an aberrantly remodeled fibroblastic reticular cell (FRC) network expressing elevated fibroblast-activated protein (FAP). RNA-Seq analyses revealed that exposure to DLBCL reprogrammed key immunoregulatory pathways in FRCs, including a switch from homeostatic to inflammatory chemokine expression and elevated antigen-presentation molecules. Functional assays showed that DLBCL-activated FRCs (DLBCL-FRCs) hindered optimal TIL and chimeric antigen receptor (CAR) T cell migration. Moreover, DLBCL-FRCs inhibited CD8+ TIL cytotoxicity in an antigen-specific manner. Notably, the interrogation of patient LNs with imaging mass cytometry identified distinct environments differing in their CD8+ TIL-FRC composition and spatial organization that associated with survival outcomes. We further demonstrated the potential to target inhibitory FRCs to rejuvenate interacting TILs. Cotreating organotypic cultures with FAP-targeted immunostimulatory drugs and a bispecific antibody (glofitamab) augmented antilymphoma TIL cytotoxicity. Our study reveals an immunosuppressive role of FRCs in DLBCL, with implications for immune evasion, disease pathogenesis, and optimizing immunotherapy for patients.
Subject(s)
Lymphoma, Large B-Cell, Diffuse , T-Lymphocytes , Humans , Mice , Animals , Lymphoma, Large B-Cell, Diffuse/pathology , Fibroblasts/metabolism , Lymph Nodes , Tumor MicroenvironmentSubject(s)
Lymphoma , Antigens, CD34 , B-Lymphocytes , Hematopoietic Stem Cell Mobilization , Humans , Lymphoma/diagnosis , Lymphoma/genetics , Lymphoma/therapy , Mutation , Stem CellsABSTRACT
Mantle cell lymphoma (MCL), a malignancy of B-lymphocytes, has a poor prognosis. It is thus necessary to improve the understanding of the pathobiology of MCL and identify factors contributing to its aggressiveness. Our studies, based on Affymetrix data from 17 MCL biopsies, real-time quantitative polymerase chain reaction data from 18 sorted primary MCL cells and 108 MCL biopsies compared to non-malignant tissue, reveals that GNAZ expression predicts poor clinical outcome of MCL patients (Cox regression, P = 0·014) and lymphocytosis (Mann-Whitney, P = 0·011). We show that GNAZ translates to Gαz protein - a signalling molecule within the G-protein coupled receptor network. Our findings suggest that GNAZ/Gαz contribute to the MCL pathobiology.
