Hemogenic Endothelium Differentiation from Human Pluripotent Stem Cells in A Feeder- and Xeno-free Defined Condition

Deriving functional hematopoietic stem and progenitor cells (HSPCs) from human pluripotent stem cells (PSCs) have been an elusive goal for autologous ...

Generation of Natural Killer Cells from Human Expanded Potential Stem Cells

The differentiation of natural killer (NK) cells from human pluripotent stem cells allows for research on and the manufacture of clinical-grade cellular ...

Center for iPS cell research and application (CiRA)

The University of Hong Kong

Centre for Translational Stem Cell Biology

Deriving hematopoietic stem cells (HSCs) from human pluripotent stem cells is one of major goals in stem cell and hematological research. To induce HSCs from human pluripotent stem cells, many attempts to mimic embryonic development through stepwise exposure to morphogens. HSCs arise from dorsal aorta of embryos then migrate and settle in the bone marrow. Development and maintenance of HSCs are controlled by the microenvironmental cues around the blood vessels (called vascular niche) through morphogens and cytokines. Vascular niche serves as a common mechanism from embryo development to life-long maintenance of HSCs. In this chapter, I discuss that how vascular niche regulates development and maintenance of HSCs and exemplify the role of vascular niche to exquisitely induce HSCs from human pluripotent stem cells.

The significance and application of vascular niche in the development and maintenance of hematopoietic stem cells.

Hematopoietic stem cell (HSC) transplantation is a curative treatment for hematologic malignancies and innate immunodeficiency, but its applications are limited to matched donors, and the availability of umbilical cord blood of immune types. Therefore, derivation of HSCs from patient-specific human induced pluripotent stem cells (hiPSCs) is a holy grail in regenerative medicine. However, derivation of HSCs from iPSCs has proven elusive. Here, the authors developed a method to derive hematopoietic stem and progenitor cells (HSPCs) by combining two established methods. The first method mimics embryonic development by directed differentiation of iPSCs into a cellular state termed hemogenic endothelium (HE) by stepwise exposure to different combinations of morphogens and cytokines. In the second method, transcription factors are induced in HE cells for specification into HSCs. By combining these approaches, the authors identified a set of select transcription factors that programmed HE cells into HSPCs with long-term and multilineage capacity in vivo. In this chapter, I provide an overview of this technology, technical tips, and future applications.

Derivation of Hematopoietic Stem and Progenitor Cells from Human Pluripotent Stem Cells.

Advanced, unresectable hepatocellular carcinoma has a dismal outcome. Multiple immune checkpoint inhibitors (ICIs) targeting the programmed-cell death 1 pathway (PD-1/L1) have been approved for the treatment of advanced HCC. However, outcomes remain undesirable and unpredictable on a patient-to-patient basis. The combination of anti-PD-1/L1 with alternative agents, chiefly cytotoxic T-lymphocyte antigen-4 (CTLA-4) ICIs or agents targeting other oncogenic pathways such as the vascular endothelial growth factor (VEGF) pathway and the c-MET pathway, has, in addition to the benefit of directly targeting alterative oncogenic pathways, in vitro evidence of synergism through altering the genomic and function signatures of T cells and expression of immune checkpoints. Several trials have been completed or are underway evaluating such combinations. Finally, studies utilizing transcriptomics and organoids are underway to establish biomarkers to predict ICI response. This review aims to discuss the biological rationale and clinical advances in ICI-based combinations in HCCs, as well as the progress and prospects of the search for the aforementioned biomarkers in ICI treatment of HCC.

Recent Advances and Future Prospects in Immune Checkpoint (ICI)-Based Combination Therapy for Advanced HCC.

Autologous chimeric antigen receptor (CAR) T cells have expanded the scope and therapeutic potential of anti-cancer therapy. Nevertheless, autologous CAR-T therapy has been challenging due to labor some manufacturing processes for every patient, and the cost due to the complexity of the process. Moreover, T cell dysfunction results from the immunosuppressive tumor microenvironment in certain patients. Considering technical challenges in autologous donors, the development of safe and efficient allogeneic CAR-T therapy will address these issues. Since the advent of the generation of immune cells from pluripotent stem cells (PSCs), numerous studies focus on the off-the-shelf generation of CAR-immune cells derived from the universal donor PSCs, which simplifies the manufacturing process and standardizes CAR-T products. In this review, we will discuss advances in the generation of immune cells from PSCs, together with the potential and perspectives of CAR-T, CAR-macrophages, and CAR-natural killer (NK) cells in cancer treatment. The combination of PSC-derived immune cells and CAR engineering will pave the way for developing next-generation cancer immunotherapy.

Off-the-Shelf Chimeric Antigen Receptor Immune Cells from Human Pluripotent Stem Cells.

The tumor microenvironment (TME) is a complex milieu consisting of lymphoid cells, myeloid cells, fibroblasts, and multiple molecules, which play a key role in tumor progression and immunotherapy. TME is characterized by immune-suppressive features, which release anti-inflammatory cytokines such as IL-4 and TGFβ to skew the T cells to a Th2 state as well to polarize tumor-associated macrophages (TAMs) to an anti-inflammatory phenotype to curb the immunotherapy. Considering the heterogeneity of the TME and its role in determining response to chimeric antigen receptor (CAR)-T cells, delineating TME at a single-cell level will provide useful information for cancer treatment. First, we discuss cellular and molecular features that curb the response to CAR-T cells, for example, high expression of immune checkpoint molecules (PD-1, LAG3) and anti-inflammatory cytokines (IL-4, TGFb) that block CAR-T cell function. Then, we summarize how newly invented single-cell technologies such as spatial multi-omics would benefit the understanding of cancer immunotherapy. Finally, we will further describe recent attempts of CAR-T to remodel TME by arming the CAR-T with anti-PD-1 single-chain variants or Th1 triggering cytokines (such as IL-7, IL-12) to remodel TME into a pro-inflammatory state. Herein, we review the single-cell-level signatures of TME and the strategies of CAR-T to remodel TME.

The Single-Cell Level Perspective of the Tumor Microenvironment and Its Remodeling by CAR-T Cells.

The tumor microenvironment encompasses various innate immune cells which regulate tumor progression. Exploiting innate immune cells is a new frontier of cancer immunotherapy. However, the classical surface markers for cell-type classification cannot always well-conclude the phenotype, which will further hinge our understanding. The innate immune cells include dendritic cells, monocytes/macrophages, natural killer cells, and innate lymphoid cells. They play important roles in tumor growth and survival, in some cases promoting cancer, in other cases negating cancer. The precise characterization of innate immune cells at the single-cell level will boost the potential of cancer immunotherapy. With the development of single-cell RNA sequencing technology, the transcriptome of each cell in the tumor microenvironment can be dissected at a single-cell level, which paves a way for a better understanding of the cell type and its functions. Here, we summarize the subtypes and functions of innate immune cells in the tumor microenvironment based on recent literature on single-cell technology. We provide updates on recent achievements and prospects for how to exploit novel functions of tumor-associated innate immune cells and target them for cancer immunotherapy.

Deciphering Innate Immune Cell-Tumor Microenvironment Crosstalk at a Single-Cell Level.

Chimeric antigen receptors (CAR) T cells (CAR-T) mark a significant step towards producing safe and effective personal anticancer treatments. CAR-T strategies engineers the T cells from the patients to allow specific binding to a tumour-specific antigen. CAR-Ts are a second-wave offensive strategy to clear out remaining chemotherapy-resistant tumour cells. Though showing practical antitumor abilities in multiple haematological malignancies and solid tumour cancers, the issues of antigen escape, tumour infiltration/penetration, and toxicity side effects limit the usage of prolonged CAR-T therapies. However, engineering immunology has exploited human stem cell-based CAR-T therapies and the development of CAR-M (macrophage) therapies to combat the disadvantages of conventional CAR-T therapies. In this review, we will highlight the challenges of CAR-T therapies and combat them with engineering immunology for cancer immunotherapy.

Ryohichi Sugimura

Center for iPS cell research and application (CiRA)

Hemogenic Endothelium Differentiation from Human Pluripotent Stem Cells in A Feeder- and Xeno-free Defined Condition

Generation of Natural Killer Cells from Human Expanded Potential Stem Cells