Project description:Despite the widespread application of immunotherapy, treating immune-cold tumors remains a significant challenge in cancer therapy. Using multiomic spatial analyses and experimental validation, we have identified MGAT1, a glycosyltransferase, as a pivotal factor governing tumor immune response. Overexpression of MGAT1 leads to immune evasion due to aberrant elevation of CD73 membrane translocation, which suppresses CD8+ T cell function, especially in immune-cold triple-negative breast cancer (TNBC). Mechanistically, addition of N-acetylglucosamine to CD73 by MGAT1 enables the CD73 dimerization necessary for CD73 loading onto VAMP3, ensuring membrane fusion. We further show that THBS1 is an upstream etiological factor orchestrating the MGAT1-CD73-VAMP3-adenosine axis in suppressing CD8+ T cell antitumor activity. Spatial transcriptomic profiling reveals spatially resolved features of interacting malignant and immune cells pertaining to expression levels of MGAT1 and CD73. In preclinical models of TNBC, W-GTF01, a newly developed inhibitor, specifically blocked the MGAT1-catalyzed CD73 glycosylation, sensitizing refractory tumors to anti-PD-L1 therapy via restoring capacity to elicit a CD8+ IFNγ-producing T cell response. Collectively, our findings uncover a strategy for targeting the immunosuppressive molecule CD73 by inhibiting MGAT1.
Project description:The understanding of heterogeneity of human memory T cells will help to know the function, development and maintenance of memory population, then to improve the recall response or effective immunotherapy. Ecto-5’-nucleotidase CD73 expression in four subsets of memory T cells decreases with aging. The resistance to apoptosis and high expression of IL7R entitle CD73+ memory T cells to be long-lived population. We found antigen-specific memory T cells have overwhelming CD73 expression. The transcriptional and chromatin accessibility profiles indicate the elevated effector functions in CD73+ memory CD4 T cells comparing to CD73- counterparts. Homer analysis and Transcriptional factor (TF)-regulatory element-target gene triplet network clearly show the crucial role of RUNT and NR family TFs in CD73+ cells. Furthermore, CD73+ memory CD4 T cells were prone to differentiate into TRM-like cells under in-vitro sequential TCR and TGF/IL-15 signaling. The decreased percentage of CD73+ memory T cells with age leads to the less replenishment of TRM cells from peripheral blood.
Project description:High levels of ecto-5'-nucleotidase (CD73) have been implicated in immune suppression and tumor progression. Elevated levels of CD73 has also been observed in patients who progress on anti–PD-1 immunotherapy. While regulatory T cells can express CD73 and inhibit T cell responses via the production of adenosine, less is known if conventional T cells and natural killer (NK) cells can express CD73. We found that the expression of CD73 is restricted to tumor-infiltrating NK cells and the frequency of these cells correlate with larger tumor size in patients with breast cancer. In addition, the expression of other immune checkpoint receptors including LAG-3 and VISTA was significantly higher in CD73 positive NK cells than on CD73 negative NK cells. Furthermore, the prognostic value of CD73 gene expression was influenced by NK cell signature expressed in patients with breast cancer and sarcoma. Mechanistically, upon engagement of 4-1BBL on tumor cells, NK cells transport CD73 in intracellular vesicles to the cell surface and extracellular space via actin polymerization-dependent exocytosis. These CD73 positive NK cells undergo transcriptional reprogramming and upregulate IL10 production via STAT3 transcriptional activity and suppress CD4 T cell activity. Altogether, our results support that tumors can hijack NK cells as a means to escape immunity and that CD73 expression defines an inducible population of NK cells with immune regulatory properties within the tumor microenvironment.
Project description:We identified CD73+ bone marrow stromal cells as hematopoietic niche candidates. To further validate our finding, we tested the functional role of CD73 during bone marrow transplantation using CD73-/- mice. We evaluated the transcriptome of transplanted WT hematopoietic stem and progenitor cells from WT or CD73-/- recipient mice and found changes in metabolic, cell cycle and signaling genes.
Project description:The understanding of heterogeneity of human memory T cells will help to know the function, development and maintenance of memory population, then to improve the recall response or effective immunotherapy. Ecto-5’-nucleotidase CD73 expression in four subsets of memory T cells decreases with aging. The resistance to apoptosis and high expression of IL7R entitle CD73+ memory T cells to be long-lived population. We found antigen-specific memory T cells have overwhelming CD73 expression. The transcriptional and chromatin accessibility profiles indicate the elevated effector functions in CD73+ memory CD4 T cells comparing to CD73- counterparts. Homer analysis and Transcriptional factor (TF)-regulatory element-target gene triplet network clearly show the crucial role of RUNT and NR family TFs in CD73+ cells. Furthermore, CD73+ memory CD4 T cells were prone to differentiate into TRM-like cells under in-vitro sequential TCR and TGF/IL-15 signaling. The decreased percentage of CD73+ memory T cells with age leads to the less replenishment of TRM cells from peripheral blood.
Project description:Triple negative breast cancer (TNBC) is a heterogeneous and clinically aggressive disease for which there is no targeted therapy. Here we report the preferential and high sensitivity of TNBCs to BET bromodomain inhibitors such as JQ1 manifested by cell cycle arrest in early G1, apoptosis, and induction of markers of luminal epithelial differentiation in vitro and in vivo. The sensitivity of TNBC and other tumor types to BET inhibition establishes a rationale for clinical investigation, and a motivation to understand mechanisms of resistance. After engendering acquired resistance to BET inhibition in previously sensitive TNBCs, we utilized integrative approaches to identify a unique mechanism of epigenomic resistance to this epigenetic therapy. Resistant cells remain dependent on BRD4, confirmed by RNA interference. However, TNBC cells adapt to BET bromodomain inhibition by re-recruitment of unmutated BRD4 to super-enhancers, now in a bromodomain-independent manner. Proteomic studies of resistant TNBC identify hyper-phosphorylation of BRD4 and strong association with MED1. Together, these studies provide a rationale for BET inhibition in TNBC and argue for combination strategies to anticipate clinical drug resistance. ChIP-seq in parental and JQ1 resistant triple negative breast cancer (TNBC) in response to DMSO or JQ1 treatment
Project description:Triple negative breast cancer (TNBC) is a heterogeneous and clinically aggressive disease for which there is no targeted therapy. Here we report the preferential and high sensitivity of TNBCs to BET bromodomain inhibitors such as JQ1 manifested by cell cycle arrest in early G1, apoptosis, and induction of markers of luminal epithelial differentiation in vitro and in vivo. The sensitivity of TNBC and other tumor types to BET inhibition establishes a rationale for clinical investigation, and a motivation to understand mechanisms of resistance. After engendering acquired resistance to BET inhibition in previously sensitive TNBCs, we utilized integrative approaches to identify a unique mechanism of epigenomic resistance to this epigenetic therapy. Resistant cells remain dependent on BRD4, confirmed by RNA interference. However, TNBC cells adapt to BET bromodomain inhibition by re-recruitment of unmutated BRD4 to super-enhancers, now in a bromodomain-independent manner. Proteomic studies of resistant TNBC identify hyper-phosphorylation of BRD4 and strong association with MED1. Together, these studies provide a rationale for BET inhibition in TNBC and argue for combination strategies to anticipate clinical drug resistance. Chem-Seq in parental and JQ1 resistant triple negative breast cancer (TNBC)
Project description:Recent studies have shown that non-enzymatic function of CD73 play a key role in tumor progression, but this function of CD73 in pancreatic cancer cells has not been studied. In the present study, PANC-1 cell lines were transfected with CD73 siRNA, and proliferation ability and cell cycle was significantly inhibited. However, little is known about the mechanisms involved in CD73 regulation in tumors.