技术资料

Early childhood tumours arise from transformed embryonic cells,which often carry large copy number alterations (CNA). However,it remains unclear how CNAs contribute to embryonic tumourigenesis due to a lack of suitable models. Here we employ female human embryonic stem cell (hESC) differentiation and single-cell transcriptome and epigenome analysis to assess the effects of chromosome 17q/1q gains,which are prevalent in the embryonal tumour neuroblastoma (NB). We show that CNAs impair the specification of trunk neural crest (NC) cells and their sympathoadrenal derivatives,the putative cells-of-origin of NB. This effect is exacerbated upon overexpression of MYCN,whose amplification co-occurs with CNAs in NB. Moreover,CNAs potentiate the pro-tumourigenic effects of MYCN and mutant NC cells resemble NB cells in tumours. These changes correlate with a stepwise aberration of developmental transcription factor networks. Together,our results sketch a mechanistic framework for the CNA-driven initiation of embryonal tumours. Subject terms: Paediatric cancer,Stem cells,Disease model,Cancer genomics,Embryonal neoplasms View Publication

Hematopoiesis continues throughout life to produce all types of blood cells from hematopoietic stem cells (HSCs). Metabolic state is a known regulator of HSC self-renewal and differentiation,but whether and how metabolic sensor O -GlcNAcylation,which can be modulated via an inhibition of its cycling enzymes O -GlcNAcase (OGA) and O -GlcNAc transferase (OGT),contributes to hematopoiesis remains largely unknown. Herein,isogenic,single-cell clones of OGA -depleted (OGAi) and OGT -depleted (OGTi) human induced pluripotent stem cells (hiPSCs) were successfully generated from the master hiPSC line MUSIi012-A,which were reprogrammed from CD34 + hematopoietic stem/progenitor cells (HSPCs) containing epigenetic memory. The established OGAi and OGTi hiPSCs exhibiting an increase or decrease in cellular O -GlcNAcylation concomitant with their loss of OGA and OGT,respectively,appeared normal in phenotype and karyotype,and retained pluripotency,although they may favor differentiation toward certain germ lineages. Upon hematopoietic differentiation through mesoderm induction and endothelial-to-hematopoietic transition,we found that OGA inhibition accelerates hiPSC commitment toward HSPCs and that disruption of O -GlcNAc homeostasis affects their commitment toward erythroid lineage. The differentiated HSPCs from all groups were capable of giving rise to all hematopoietic progenitors,thus confirming their functional characteristics. Altogether,the established single-cell clones of OGTi and OGAi hiPSCs represent a valuable platform for further dissecting the roles of O -GlcNAcylation in blood cell development at various stages and lineages of blood cells. The incomplete knockout of OGA and OGT in these hiPSCs makes them susceptible to additional manipulation,i.e.,by small molecules,allowing the molecular dynamics studies of O -GlcNAcylation. View Publication

Hemangiosarcoma and angiosarcoma are soft-tissue sarcomas of blood vessel–forming cells in dogs and humans,respectively. These vasoformative sarcomas are aggressive and highly metastatic,with disorganized,irregular blood-filled vascular spaces. Our objective was to define molecular programs which support the niche that enables progression of canine hemangiosarcoma and human angiosarcoma. Dog-in-mouse hemangiosarcoma xenografts recapitulated the vasoformative and highly angiogenic morphology and molecular characteristics of primary tumors. Blood vessels in the tumors were complex and disorganized,and they were lined by both donor and host cells. In a series of xenografts,we observed that the transplanted hemangiosarcoma cells created exuberant myeloid hyperplasia and gave rise to lymphoproliferative tumors of mouse origin. Our functional analyses indicate that hemangiosarcoma cells generate a microenvironment that supports expansion and differentiation of hematopoietic progenitor populations. Furthermore,gene expression profiling data revealed hemangiosarcoma cells expressed a repertoire of hematopoietic cytokines capable of regulating the surrounding stromal cells. We conclude that canine hemangiosarcomas,and possibly human angiosarcomas,maintain molecular properties that provide hematopoietic support and facilitate stromal reactions,suggesting their potential involvement in promoting the growth of hematopoietic tumors. We demonstrate that hemangiosarcomas regulate molecular programs supporting hematopoietic expansion and differentiation,providing insights into their potential roles in creating a permissive stromal-immune environment for tumor progression. View Publication

Cohesin plays a crucial role in the organization of topologically-associated domains (TADs),which influence gene expression and DNA replication timing. Whether epigenetic regulators may affect TADs via cohesin to mediate DNA replication remains elusive. Here,we discover that the histone demethylase PHF2 associates with RAD21,a core subunit of cohesin,to regulate DNA replication in mouse neural stem cells (NSC). PHF2 loss impairs DNA replication due to the activation of dormant replication origins in NSC. Notably,the PHF2/RAD21 co-bound genomic regions are characterized by CTCF enrichment and epigenomic features that resemble efficient,active replication origins,and can act as boundaries to separate adjacent domains. Accordingly,PHF2 loss weakens TADs and chromatin loops at the co-bound loci due to reduced RAD21 occupancy. The observed topological and DNA replication defects in PHF2 KO NSC support a cohesin-dependent mechanism. Furthermore,we demonstrate that the PHF2/RAD21 complex exerts little effect on gene regulation,and that PHF2’s histone-demethylase activity is dispensable for normal DNA replication and proliferation of NSC. We propose that PHF2 may serve as a topological accessory to cohesin for cohesin localization to TADs and chromatin loops,where cohesin represses dormant replication origins directly or indirectly,to sustain DNA replication in NSC. View Publication

Adult T-cell leukemia/lymphoma (ATL) occurs after human T-cell leukemia virus type-1 (HTLV-1) infection with a long latency period exceeding several decades. This implies the presence of immune evasion mechanisms for HTLV-1-infected T cells. Although ATL cells have a CD4 + CD25 + phenotype similar to that of regulatory T cells (Tregs),they do not always possess the immunosuppressive functions of Tregs. Factors that impart effective immunosuppressive functions to HTLV-1-infected cells may exist. A previous study identified a new CD13 + Treg subpopulation with enhanced immunosuppressive activity. We,herein,describe the paired CD13 − (designated as MT-50.1) and CD13 + (MT-50.4) HTLV-1-infected T-cell lines with Treg-like phenotype,derived from the peripheral blood of a single patient with lymphoma-type ATL. The cell lines were found to be derived from HTLV-1-infected non-leukemic cells. MT-50.4 cells secreted higher levels of immunosuppressive cytokines,IL-10 and TGF-β,expressed higher levels of Foxp3,and showed stronger suppression of CD4 + CD25 − T cell proliferation than MT-50.1 cells. Furthermore,the CD13 inhibitor bestatin significantly attenuated MT-50.4 cell growth,while it did not for MT-50.1 cells. These findings suggest that CD13 expression may be involved in the increased Treg-like activity of MT-50.4 cells. Hence,MT-50.4 cells will be useful for in-depth studies of CD13 + Foxp3 + HTLV-1-infected cells. Subject terms: Cancer,Microbiology,Oncology View Publication

Chimeric antigen receptor (CAR) T cell therapy has emerged as a powerful therapeutic approach against a range of hematologic malignancies. While the incorporation of CD28 or 4-1BB costimulatory signaling domains into CARs revolutionized immune responses,there is an exciting prospect of further enhancing CAR functionality. Here,we investigated the design of CD19 CARs enriched with distinct Toll-like receptor 4 (TLR4),myeloid differentiation primary response 88 (MyD88),or Toll/IL-1 domain-containing adaptor-inducing interferon (IFN)-β (TRIF) costimulatory domains. Screening of various designs identified several candidates with no tonic activity but with increased CD19 target cell-dependent interleukin (IL)-2 production. Human T cells transduced with the selected CAR construct exhibited augmented hIL-2 and hIFN-γ induction and cytotoxicity when cocultured with CD19-positive lymphoma and solid-tumor cell lines. RNA sequencing (RNA-seq) analysis demonstrated the upregulation of some genes involved in the innate immune response and T cell activation and proliferation. In experiments on a xenogeneic solid-tumor mice model,MyD88 and TLR4 CAR T cells exhibited prolonged remission. This study demonstrates that the integration of a truncated TLR4 signaling costimulatory domain could provide immunotherapeutic potential against both hematologic malignancies and solid tumors. View Publication

Precise gene editing uncovers mis-splicing of BUBR1 and CDC27 in human SF3B1-mutant HSPCs,leading to activation of mitotic checkpoint and rendering the cells sensitive to CHK1 inhibitor prexasertib. View Publication

Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However,the oxygenation heterogeneity and dense extracellular matrix (ECM) of tumor,as well as the potential resistance to chemotherapy,have severely impeded the resulting overall efficacy of HAP. A HAP potentiating strategy is proposed based on ultrasound responsive nanodroplets (PTP@PLGA),which is composed of protoporphyrin (PpIX),perfluoropropane (PFP) and a typical HAP,tirapazamine (TPZ). The intense vaporization of PFP upon ultrasound irradiation can magnify the sonomechanical effect,which loosens the ECM to promote the penetration of TPZ into the deep hypoxic region. Meanwhile,the PpIX enabled sonodynamic effect can further reduce the oxygen level,thus activating the TPZ in the relatively normoxic region as well. Surprisingly,abovementioned ultrasound effect also results in the downregulation of the stemness of cancer cells,which is highly associated with drug-refractoriness. This work manifests an ideal example of ultrasound-based nanotechnology for potentiating HAP and also reveals the potential acoustic effect of intervening cancer stem-like cells. The online version contains supplementary material available at 10.1186/s12951-024-02623-0. View Publication

Therapy-related myeloid neoplasms (t-MN) arise as a complication of chemo- and/or radiotherapy. Although t-MN can occur both in adult and childhood cancer survivors,the mechanisms driving therapy-related leukemogenesis likely vary across different ages. Chemotherapy is thought to induce driver mutations in children,whereas in adults pre-existing mutant clones are selected by the exposure. However,selective pressures induced by chemotherapy early in life are less well studied. Here,we use single-cell whole genome sequencing and phylogenetic inference to show that the founding cell of t-MN in children starts expanding after cessation of platinum exposure. In patients with Li-Fraumeni syndrome,characterized by a germline TP53 mutation,we find that the t-MN already expands during treatment,suggesting that platinum-induced growth inhibition is TP53- dependent. Our results demonstrate that germline aberrations can interact with treatment exposures in inducing t-MN,which is important for the development of more targeted,patient-specific treatment regimens and follow-up. Subject terms: Cancer genomics,Cancer genomics,Haematological cancer,Paediatric cancer View Publication

Heme oxygenase-1 (HO-1,HMOX1 ) degrades heme protecting cells from heme-induced oxidative damage. Beyond its well-established cellular functions,heme has emerged as a stabilizer of G-quadruplexes. These secondary DNA structures interfere with DNA replication. We recently revealed that nuclear HO-1 colocalizes with DNA G-quadruplexes and promotes their removal. Here,we investigate whether HO-1 safeguards cells against replication stress. Experiments were conducted in control and HMOX1 -deficient HEK293T cell lines. Immunostaining unveiled that DNA G-quadruplexes accumulated in the absence of HO-1,the effect that was further enhanced in response to δ-aminolevulinic acid (ALA),a substrate in heme synthesis. This was associated with replication stress,as evidenced by an elevated proportion of stalled forks analyzed by fiber assay. We observed the same effects in hematopoietic stem cells isolated from Hmox1 knockout mice and in a lymphoblastoid cell line from an HMOX1 -deficient patient. Interestingly,in the absence of HO-1,the speed of fork progression was higher,and the response to DNA conformational hindrance less stringent,indicating dysfunction of the PARP1-p53-p21 axis. PARP1 activity was not decreased in the absence of HO-1. Instead,we observed that HO-1 deficiency impairs the nuclear import and accumulation of p53,an effect dependent on the removal of excess heme. We also demonstrated that administering ALA is a more specific method for increasing intracellular free heme compared to treatment with hemin,which in turn induces strong lipid peroxidation. Our results indicate that protection against replication stress is a universal feature of HO-1,presumably contributing to its widely recognized cytoprotective activity. View Publication

Breast cancer is the most common cancer in women diagnosed in the U.S. and worldwide. Obesity increases breast cancer risk without clear underlying molecular mechanisms. Our studies demonstrate that circulating adipose fatty acid binding protein (A-FABP,or FABP4) links obesity-induced dysregulated lipid metabolism and breast cancer risk,thus potentially offering a new target for breast cancer treatment. We immunized FABP4 knockout mice with recombinant human FABP4 and screened hybridoma clones with specific binding to FABP4. The potential effects of antibodies on breast cancer cells in vitro were evaluated using migration,invasion,and limiting dilution assays. Tumor progression in vivo was evaluated in various types of tumorigenesis models including C57BL/6 mice,Balb/c mice,and SCID mice. The phenotype and function of immune cells in tumor microenvironment were characterized with multi-color flow cytometry. Tumor stemness was detected by ALDH assays. To characterize antigen-antibody binding capacity,we determined the dissociation constant of selected anti-FABP4 antibodies via surface plasmon resonance. Further analyses in tumor tissue were performed using 10X Genomics Visium spatial single cell technology. Herein,we report the generation of humanized monoclonal antibodies blocking FABP4 activity for breast cancer treatment in mouse models. One clone,named 12G2,which significantly reduced circulating levels of FABP4 and inhibited mammary tumor growth,was selected for further characterization. After confirming the therapeutic efficacy of the chimeric 12G2 monoclonal antibody consisting of mouse variable regions and human IgG1 constant regions,16 humanized 12G2 monoclonal antibody variants were generated by grafting its complementary determining regions to selected human germline sequences. Humanized V9 monoclonal antibody showed consistent results in inhibiting mammary tumor growth and metastasis by affecting tumor cell mitochondrial metabolism. Our current evidence suggests that targeting FABP4 with humanized monoclonal antibodies may represent a novel strategy for the treatment of breast cancer and possibly other obesity- associated diseases. The online version contains supplementary material available at 10.1186/s13058-024-01873-y. View Publication

Chemotherapy-induced peripheral neuropathy (CIPN) is a disabling side effect of cancer chemotherapy that can often limit treatment options for cancer patients or have life-long neurodegenerative consequences that reduce the patient’s quality of life. CIPN is caused by the detrimental actions of various chemotherapeutic agents on peripheral axons. Currently,there are no approved preventative measures or treatment options for CIPN,highlighting the need for the discovery of novel therapeutics and improving our understanding of disease mechanisms. In this study,we utilized human-induced pluripotent stem cell (hiPSC)-derived motor neurons as a platform to mimic axonal damage after treatment with vincristine,a chemotherapeutic used for the treatment of breast cancers,osteosarcomas,and leukemia. We screened a total of 1902 small molecules for neuroprotective properties in rescuing vincristine-induced axon growth deficits. From our primary screen,we identified 38 hit compounds that were subjected to secondary dose response screens. Six compounds showed favorable pharmacological profiles – AZD7762,A-674563,Blebbistatin,Glesatinib,KW-2449,and Pelitinib,all novel neuroprotectants against vincristine toxicity to neurons. In addition,four of these six compounds also showed efficacy against vincristine-induced growth arrest in human iPSC-derived sensory neurons. In this study,we utilized high-throughput screening of a large library of compounds in a therapeutically relevant assay. We identified several novel compounds that are efficacious in protecting different neuronal subtypes from the toxicity induced by a common chemotherapeutic agent,vincristine which could have therapeutic potential in the clinic. The online version contains supplementary material available at 10.1007/s00018-024-05340-x. View Publication