PD-L1 regulates inflammatory programs of macrophages from human pluripotent stem cells

Establishment of human expanded potential stem cell lines via preimplantation embryo cultivation and somatic cell reprogramming

We previously reported the derivation of expanded potential stem cells (EPSCs) by modulating signaling pathways involved in preimplantation embryogenesis. These cells exhibit expanded developmental potential into embryonic and extraembryonic lineages, and we have shown that human EPSCs (hEPSCs) possess trophoblast differentiation potency for generating human trophoblast stem cells. Here we report protocols for deriving stable hEPSC lines directly from morula or early blastocyst stages of human preimplantation embryos (hEPSC-em) and by reprogramming human dermal fibroblasts (human induced EPSCs) using six exogenous factors, as an extension to our previous protocols on deriving porcine EPSCs from preimplantation embryos and by reprogramming somatic cells. These hEPSC lines proliferate robustly over long-term passaging and are amenable to both simple indels and precision genome editing. We provide guidance for characterizing these newly established hEPSCs, including cell-cycle analysis, pluripotency validation and karyotyping. The hEPSCs form teratomas with embryonic and extraembryonic cell lineages and readily differentiate into human trophoblast stem cells in vitro. At the molecular level, hEPSCs have unique features such as high expression of core histone genes and low H3K27me3 levels resembling eight-cell/morula stage embryos. These properties make hEPSCs a valuable tool not only for studying early human development but also for potential applications in regenerative medicine. The protocols presented in this manuscript can be readily performed by postgraduate students or postdoctoral fellows and completed within around 2 months.

miR-223 and Chromogranin A Affect Inflammatory Immune Cell Activation in Liver Metastasis of Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) are a diverse group originating from endocrine cells/their precursors in pancreas, small intestine, or lung. The key serum marker is chromogranin A (CgA). While commonly elevated in patients with NEN, its prognostic value is still under discussion. Secretion/posttranslational proteolytic cleavage of CgA results in multiple bioactive fragments, which are essential regulators of the cardiovascular and immune system. miR-223, regulator of Nrlp3 inflammasome and neutrophil activation, was recently found to have decreased in patients with NEN. We performed flow cytometry of circulating neutrophils in a patient cohort (n = 10) with NEN, microdissection and histology of tumor tissue. Subsequently, in vitro transfections using the well-established human pancreatic NEN cell line (BON), and co-culture experiments with primary macrophages and neutrophils were performed. Serum miR-223 in patients correlated with the expression of the neutrophil activation marker CD15 in circulating cells. Neutrophilic CD62L/CD63 showed good discrimination compared to healthy controls. Immune cell-derived miR-155, miR-193 and miR-223 colocalize with neutrophil in the extra-tumoral tissue alongside Nlrp3-associated caspase-1 activation. miR-223 knockdown in BON decreased the CgA intracellularly, increased in cellular granularity and caspase-1 activation. Plasmin inhibitor a2-aP reverted those effects. Western Blot showed fragmented CgA following miR-223 knockdown, which altered the inflammatory potential of neutrophils. Our data hence provide initial insights into an immunoregulatory mechanism via miR-223 and CgA in NEN cells, as regulation of miR-223 in NEN may affect tumor-associated inflammation.

PD-L1 and IFN-γ modulate Non-Small Cell Lung Cancer (NSCLC) cell plasticity associated to immune checkpoint inhibitor (ICI)-mediated hyperprogressive disease (HPD)

BACKGROUND

Non-Small Cell Lung Cancer (NSCLC) is the leading cause of cancer death worldwide. Although immune checkpoint inhibitors (ICIs) have shown remarkable clinical efficacy, they can also induce a paradoxical cancer acceleration, known as hyperprogressive disease (HPD), whose causative mechanisms are still unclear.

METHODS

This study investigated the mechanisms of ICI resistance in an HPD-NSCLC model. Two primary cell cultures were established from samples of a NSCLC patient, before ICI initiation ("baseline", NSCLC-B) and during HPD ("hyperprogression", NSCLC-H). The cell lines were phenotypically and molecularly characterized through immunofluorescence, Western Blotting and RNA-Seq analysis. To assess cell plasticity and aggressiveness, cellular growth patterns were evaluated both in vitro and in vivo through 2D and 3D cell growth assays and patient-derived xenografts establishment. In vitro investigations, including the evaluation of cell sensitivity to interferon-gamma (IFN-γ) and cell response to PD-L1 modulation, were conducted to explore the influence of these factors on cell plasticity regulation.

RESULTS

NSCLC-H exhibited increased expression of specific CD44 isoforms and a more aggressive phenotype, including organoid formation ability, compared to NSCLC-B. Plastic changes in NSCLC-H were well described by a deep transcriptome shift, that also affected IFN-γ-related genes, including PD-L1. IFN-γ-mediated cell growth inhibition was compromised in both 2D-cultured NSCLC-B and NSCLC-H cells. Further, the cytokine induced a partial activation of both type I and type II IFN-pathway mediators, together with a striking increase in NSCLC-B growth in 3D cell culture systems. Finally, low IFN-γ doses and PD-L1 modulation both promoted plastic changes in NSCLC-B, increasing CD44 expression and its ability to produce spheres.

CONCLUSIONS

Our findings identified plasticity as a relevant hallmark of ICI-mediated HPD by demonstrating that ICIs can modulate the IFN-γ and PD-L1 pathways, driving tumor cell plasticity and fueling HPD development.

PD-L1 blockade immunotherapy rewires cancer-induced emergency myelopoiesis

Introduction

Immune checkpoint blockade (ICB) immunotherapy has revolutionized cancer treatment, demonstrating exceptional clinical responses in a wide range of cancers. Despite the success, a significant proportion of patients still fail to respond, highlighting the existence of unappreciated mechanisms of immunotherapy resistance. Delineating such mechanisms is paramount to minimize immunotherapy failures and optimize the clinical benefit.

Methods

In this study, we treated tumour-bearing mice with PD-L1 blockage antibody (aPD-L1) immunotherapy, to investigate its effects on cancer-induced emergency myelopoiesis, focusing on bone marrow (BM) hematopoietic stem and progenitor cells (HSPCs). We examined the impact of aPD-L1 treatment on HSPC quiescence, proliferation, transcriptomic profile, and functionality.

Results

Herein, we reveal that aPD-L1 in tumour-bearing mice targets the HSPCs in the BM, mediating their exit from quiescence and promoting their proliferation. Notably, disruption of the PDL1/PD1 axis induces transcriptomic reprogramming in HSPCs, observed in both individuals with Hodgkin lymphoma (HL) and tumour-bearing mice, shifting towards an inflammatory state. Furthermore, HSPCs from aPDL1-treated mice demonstrated resistance to cancer-induced emergency myelopoiesis, evidenced by a lower generation of MDSCs compared to control-treated mice.

Discussion

Our findings shed light on unrecognized mechanisms of action of ICB immunotherapy in cancer, which involves targeting of BM-driven HSPCs and reprogramming of cancer-induced emergency myelopoiesis.

SARS-CoV-2 infection activates inflammatory macrophages in vascular immune organoids

SARS-CoV-2 provokes devastating tissue damage by cytokine release syndrome and leads to multi-organ failure. Modeling the process of immune cell activation and subsequent tissue damage is a significant task. Organoids from human tissues advanced our understanding of SARS-CoV-2 infection mechanisms though, they are missing crucial components: immune cells and endothelial cells. This study aims to generate organoids with these components. We established vascular immune organoids from human pluripotent stem cells and examined the effect of SARS-CoV-2 infection. We demonstrated that infections activated inflammatory macrophages. Notably, the upregulation of interferon signaling supports macrophages' role in cytokine release syndrome. We propose vascular immune organoids are a useful platform to model and discover factors that ameliorate SARS-CoV-2-mediated cytokine release syndrome.

Breakthroughs in synthetic controlling strategies for precision in CAR-T therapy

Chimeric antigen receptors (CAR) are synthetic receptors engineered to target a user-defined antigen. They comprise an extracellular single-chain variable fragment for target recognition and intracellular signalling domains commonly derived from immune cells. CAR-T cells have proven to be successful in therapy of some cancers. CAR-T cells are activated upon antigen-priming and subsequent intracellular signalling. However, tonic signalling in CAR-T cells remains a challenge in developing CAR-T therapeutics of high efficacy as it causes early T-cell exhaustion, limiting therapeutic persistence. Moreover, a poor choice of target antigen leads to off-target cytotoxicity, often hampering the host's survival. In addition, conventional methods of delivering CAR gene circuits utilise viral vectors, such as lentiviruses and retroviruses, which insert the CAR gene circuits into transcriptionally active sites in the genome. This increases the risks of malignant transformation due to improper genome integration. Optimisation in CAR-T engineering, from the architecture of CAR gene circuits to the structure of CAR and the behaviour of CAR-T cells, is paramount to ensure high efficacy, persistence, and precision in CAR-T therapy. This review provides insights into engineering CAR-T cells for precision in cancer therapy by highlighting the key strategies recently developed to optimise the function and efficiency of CARs. The delivery method of CAR gene circuits, circuit and structural modification of CAR, T-cell phenotype manipulation and T-cell arming will be discussed to accentuate their interplay in regulating CAR-T therapy's safety, precision, and efficacy.

Anti-PD-L1-Based Bispecific Antibodies Targeting Co-Inhibitory and Co-Stimulatory Molecules for Cancer Immunotherapy

Targeting PD-L1 via monospecific antibodies has shown durable clinical benefits and long-term remissions where patients exhibit no clinical cancer signs for many years after treatment. However, the durable clinical benefits and long-term remissions by anti-PD-L1 monotherapy have been limited to a small fraction of patients with certain cancer types. Targeting PD-L1 via bispecific antibodies (referred to as anti-PD-L1-based bsAbs) which can simultaneously bind to both co-inhibitory and co-stimulatory molecules may increase the durable antitumor responses in patients who would not benefit from PD-L1 monotherapy. A growing number of anti-PD-L1-based bsAbs have been developed to fight against this deadly disease. This review summarizes recent advances of anti-PD-L1-based bsAbs for cancer immunotherapy in patents and literatures, and discusses their anti-tumor efficacies in vitro and in vivo. Over 50 anti-PD-L1-based bsAbs targeting both co-inhibitory and co-stimulatory molecules have been investigated in biological testing or in clinical trials since 2017. At least eleven proteins, such as CTLA-4, LAG-3, PD-1, PD-L2, TIM-3, TIGIT, CD28, CD27, OX40, CD137, and ICOS, are involved in these investigations. Twenty-two anti-PD-L1-based bsAbs are being evaluated to treat various advanced cancers in clinical trials, wherein the indications include NSCLC, SNSCLC, SCLC, PDA, MBNHL, SCCHN, UC, EC, TNBC, CC, and some other malignancies. The released data from clinical trials indicated that most of the anti-PD-L1-based bsAbs were well-tolerated and showed promising antitumor efficacy in patients with advanced solid tumors. However, since the approved and investigational bsAbs have shown much more significant adverse reactions compared to PD-L1 monospecific antibodies, anti-PD-L1-based bsAbs may be further optimized via molecular structure modification to avoid or reduce these adverse reactions.