Project description:Tumor cells orchestrate their microenvironment. Here, we provide biochemical, structural, functional and clinical evidence that Cathepsin S (CTSS) alterations induce a tumor-promoting immune microenvironment in follicular lymphoma (FL). We found CTSS mutations at Y132 in 6% of FL (19/305). Another 13% (37/286) had CTSS amplification, which was associated with higher CTSS expression. CTSS Y132 mutations lead to accelerated autocatalytic conversion from pro-CTSS to active CTSS and increase substrate cleavage, including CD74 which regulates MHC-II-restricted antigen presentation. Lymphoma cells with hyperactive CTSS more efficiently activated antigen-specific CD4+ T-cells in vitro. Tumors with hyperactive CTSS showed increased CD4+ T-cell infiltration and proinflammatory cytokine perturbation in a mouse model and in human FLs. In mice, this CTSS-induced immune microenvironment promoted tumor growth. Clinically, patients with CTSS-hyperactive FL had better treatment outcomes with standard immunochemotherapies, indicating that these immunosuppressive regimens target both the lymphoma cells and the tumor-promoting immune microenvironment. Digital multiplexed gene expression profiling of formalin-fixed and paraffin-embedded biopsy specimens of the GLSG2000 cohort was performed as previously described (Hellmuth et al., Blood 2018)
Project description:Tumor cells orchestrate their microenvironment. Here, we provide biochemical, structural, functional and clinical evidence that Cathepsin S (CTSS) alterations induce a tumor-promoting immune microenvironment in follicular lymphoma (FL). We found CTSS mutations at Y132 in 6% of FL (19/305). Another 13% (37/286) had CTSS amplification, which was associated with higher CTSS expression. CTSS Y132 mutations lead to accelerated autocatalytic conversion from pro-CTSS to active CTSS and increase substrate cleavage, including CD74 which regulates MHC-II-restricted antigen presentation. Lymphoma cells with hyperactive CTSS more efficiently activated antigen-specific CD4+ T-cells in vitro. Tumors with hyperactive CTSS showed increased CD4+ T-cell infiltration and proinflammatory cytokine perturbation in a mouse model and in human FLs. In mice, this CTSS-induced immune microenvironment promoted tumor growth. Clinically, patients with CTSS-hyperactive FL had better treatment outcomes with standard immunochemotherapies, indicating that these immunosuppressive regimens target both the lymphoma cells and the tumor-promoting immune microenvironment. Digital multiplexed gene expression profiling of formalin-fixed and paraffin-embedded biopsy specimens of the validation cohort was performed as previously described (Hellmuth et al., Blood 2018)
Project description:Transcriptomic profiling; Determination of the transcriptomic similarity between Egfr fl/fl and Met fl/fl progenitor cells isolated from excised livers (n=3, each)
Project description:Twenty percent of follicular lymphoma (FL) patients relapse early with poor outcomes; however, the molecular mechanisms underlying this aggressive feature are unknown. Using a multiomics approach, we show that FL patients with elevated IRF4 expression (IRF4hi) have poor prognosis, dysregulated immune signaling, and a suppressive tumor microenvironment. Loss- and gain-of-function experiments in IRF4hi lymphoma cells, along with chromatin profiling, demonstrate that IRF4 impairs their interaction with T cells by repressing antigen presentation and co-receptor gene modules, while promoting the expression of cytokines that antagonize TFH and Treg functions. Additionally, IRF4 rewires tumor metabolism which restricts glucose availability to immune cells. Silencing of IRF4 inhibits tumor cell growth, and restores immune surveillance mechanisms, thus representing a promising target for therapy. Our data suggest that IRF4hi lymphoma cells co-opt a developmental mechanism used to exit the germinal center response in promoting a more aggressive cancer via engagement of multiple immune-evasive mechanisms.
Project description:Follicular lymphoma (FL) is a B-cell lymphoma with a complex tumor microenvironment that is rich in non-malignant immune cells. We applied single-cell RNA-sequencing to characterize the immune microenvironment of FL. This provides a classification framework of the FL microenvironment, their association with FL genotypes and antigen presentation, and informs different potential immunotherapeutic strategies.
Project description:Follicular lymphoma (FL) is a B-cell lymphoma with a complex tumor microenvironment that is rich in non-malignant immune cells. We applied single-cell RNA-sequencing to characterize the immune microenvironment of FL. This provides a classification framework of the FL microenvironment, their association with FL genotypes and antigen presentation, and informs different potential immunotherapeutic strategies.
Project description:Tumor cells can induce their own advantageous microenvironment. Here, we describe aberrant cathepsin S (CTSS) activity to modulate T-cell activation in follicular lymphoma (FL). In donor-derived FLs following bone marrow transplantation, we identified independent acquisition of CTSS mutations at Y132 in the donor´s and recipient's tumors. In a larger cohort, 6% of FL (20/312) harbored CTSS mutations, mostly Y132D, another 14% had CTSS amplification (40/280). Y132D leads to accelerated conversion from pro-CTSS to active CTSS and increased substrate cleavage, including CD74, which regulates MHC-II restricted antigen-presentation. In co-culture experiments, CTSS mutant lymphoma cells induced increased antigen-specific CD4+ T-cell activation. Moreover, antigen-processing was the top upregulated pathway in CTSS mutant primary FL biopsies. Thus, aberrant CTSS activity is a promising target in lymphoma.
Project description:Twenty percent of follicular lymphoma (FL) patients relapse early with poor outcomes; however, the molecular mechanisms underlying this aggressive behavior are unknown. Using a multiomics approach, we show that FL patients with elevated IRF4 expression (IRF4hi) have increased transformation risk, dysregulated immune signaling, and a suppressive tumor microenvironment. Loss- and gain-of-function experiments in IRF4hi lymphoma cells, along with chromatin profiling, demonstrate that IRF4 impairs their interaction with T cells by repressing antigen presentation and co-receptor gene modules, while promoting the expression of cytokines that antagonize TFH and Treg functions. Additionally, IRF4 rewires tumor metabolism which restricts glucose availability to immune cells. Silencing of IRF4 inhibits tumor cell growth and restores immune surveillance mechanisms, thus representing a promising target for therapy. Our data suggest that IRF4hi lymphoma cells co-opt a developmental mechanism used to exit the germinal center response in promoting a more aggressive cancer via engagement of multiple immune-evasive mechanisms.