Project description:To characterize the spatial tumor microenvironment (TME) of high-grade serous ovarian cancer (HGSC) at the single cell level, we performed single-cell RNA sequencing (scRNA-seq) on 48 tumor or ascites samples from 29 HGSC patients. This data set includes paired scRNA-seq data from chemo-naive and post-neoadjuvant chemotherapy (IDS) samples of 22 HGSC patients.
Project description:To uncover the intricate, chemotherapy-induced spatiotemporal remodeling of the tumor microenvironment, we conducted integrative spatial and molecular characterization of 97 high-grade serous ovarian cancer (HGSC) samples collected before and after chemotherapy. Using single-cell and spatial analyses, we identify increasingly versatile immune cell states, which form spatiotemporally dynamic microcommunities at the tumor-stroma interface. We demonstrate that chemotherapy triggers spatial redistribution and exhaustion of CD8+ T cells due to prolonged antigen presentation by macrophages, both within interconnected myeloid networks termed "Myelonets" and at the tumor stroma interface. Single-cell and spatial transcriptomics identifies prominent TIGIT-NECTIN2 ligand-receptor interactions induced by chemotherapy. Using a functional patient-derived immuno-oncology platform, we show that CD8+T-cell activity can be boosted by combining immune checkpoint blockade with chemotherapy. Our discovery of chemotherapy-induced myeloid-driven spatial T-cell exhaustion paves the way for novel immunotherapeutic strategies to unleash CD8+ T-cell-mediated anti-tumor immunity in HGSC.
Project description:Cytotoxic chemotherapy is used to treat many thousands of patients across many cancer types annually. Recent studies have demonstrated that chemotherapy causes systemic response that can be exploited to promote cancer cell survival and dissemination, termed “chemotherapy-induced metastasis. However, there have been no studies investigating how chemotherapy alters the extracellular matrix of breast tumors, or if those changes might help to support metastatic dissemination. Here, we report the first characterization of the chemotherapy-treated breast cancer matrisome using the MMTV-PyMT transgenic mouse model of breast cancer. We identify distinct changes induced by different cytotoxic chemotherapies. In particular, we identify collagen IV as significantly associated with taxane-based chemotherapy treatment. Biological validation confirmed collagen IV as chemotherapy-associated and identified collagen IV-driven Src and FAK signaling as important mediators of invasion in the post-chemotherapy tumor microenvironment.
Project description:Some neuroblastoma patients relapse after chemotherapy. Here, a Th-MYCNCPM32 mouse model usually have spontaneously tumours which are sensitive to chemotherapy. By treating mice with consecutive cycles of sublethal cyclophosphamide (CPM) using a personal dose escalation protocol (PDE), resistant tumours may develop. This experiment aims to compare the expression profiles (RNA-Seq) of sensitive and resistant MYCN driven tumours in order to understand the mechanisms behind resistance. Samples also presented cross-resistance to vincristine and doxorubicin.
Project description:Little is known about the roles of Rictor/mTORC2 in the leukemogenesis of AML. Here, we demonstrated that Rictor is essential for the maintenance of MLL-driven leukemia by preventing LSCs from exhaustion. Rictor depletion led to a reactive activation of mTORC1 signaling by facilitating the assembly of mTORC1. Hyperactivated mTORC1 signaling in turn drove LSCs into cycling, compromised the quiescence of LSCs and eventually exhausted their capacity to generate leukemia. At the same time, loss of Rictor had led to a reactive activation of FoxO3a in leukemia cells, which acts as negative feedback to restrain greater over-reactivation of mTORC1 activity and paradoxically protects leukemia cells from exhaustion. Simultaneous depletion of Rictor and FoxO3a enabled rapid exhaustion of MLL LSCs and a quick eradication of MLL leukemia. As such, our present findings highlighted a pivotal regulatory axis of Rictor-FoxO3a in maintaining quiescence and the stemness of LSCs. To understand the critical molecular events caused by Rictor loss in MLL-AF9-driven leukemia,the K+Gâ mice BM cells were sorted from the 1st BMT of RictorÎ/Î(MA9_R1,MA9_R2,MA9_R3) or control(MA9_C1,MA9_C2,MA9_C3), and subjected to microarray analysis on Affymetrix microarrays.Furthermore, the MLL-NRIP3-driven mice model was chosen for further examination.The K+Gâ mice BM cells were sorted from the 1st BMT of RictorÎ/Î(MN3_R1,MN3_R2,MN3_R3) or control(MN3_C1,MN3_C2,MN3_C3), and subjected to microarray analysis on Affymetrix microarrays.