Humanized mice in translational biomedical research

Strategies for neoantigen screening and immunogenicity validation in cancer immunotherapy (Review)

Cancer immunotherapy stimulates and enhances antitumor immune responses to eliminate cancer cells. Neoantigens, which originate from specific mutations within tumor cells, are key targets in cancer immunotherapy. Neoantigens manifest as abnormal peptide fragments or protein segments that are uniquely expressed in tumor cells, making them highly immunogenic. As a result, they activate the immune system, particularly T cell‑mediated immune responses, effectively identifying and eliminating tumor cells. Certain tumor‑associated antigens that are abnormally expressed in normal host proteins in cancer cells are promising targets for immunotherapy. Neoantigens derived from mutated proteins in cancer cells offer true cancer specificity and are often highly immunogenic. Furthermore, most neoantigens are unique to each patient, highlighting the need for personalized treatment strategies. The precise identification and screening of neoantigens are key for improving treatment efficacy and developing individualized therapeutic plans. The neoantigen prediction process involves somatic mutation identification, human leukocyte antigen (HLA) typing, peptide processing and peptide‑HLA binding prediction. The present review summarizes the major current methods used for neoantigen screening, available computational tools and the advantages and limitations of various techniques. Additionally, the present review aimed to summarize experimental strategies for validating the immunogenicity of the predicted neoantigens, which will determine whether these neoantigens can effectively trigger immune responses, as well as challenges encountered during neoantigen screening, providing relevant recommendations for the optimization of neoantigen‑based immunotherapy.

Animal models in preclinical metastatic breast cancer immunotherapy research: A systematic review and meta-analysis of efficacy outcomes

Breast cancer, particularly metastatic breast cancer (MBC), presents aggressive clinical challenges with limited treatment success. Immunotherapy has emerged as a promising approach, however, discrepancies between preclinical animal models and human cancers complicate translation to clinical outcomes. This systematic review and meta-analysis evaluated the effect of immunotherapy on primary and metastatic tumor regression in animal models of MBC and assessed the models' appropriateness and reproducibility to improve future preclinical study design. Following a preregistered protocol in PROSPERO (CRD42021207033), we conducted searches in MEDLINE, Embase, and Web of Science databases, yielding 2255 studies for title/abstract screening and 108 studies included after full-text screening. All included studies used mouse models, assessing primary outcomes through tumor volume or weight and metastatic outcomes via nodule count or bioluminescence. Only 14% of studies fully reported experimental animal characteristics, and 43% provided detailed experimental procedures. Of 105 articles (293 comparisons) included in the meta-analysis, pooled effect sizes indicated significant reductions in both primary and metastatic tumors. However, high heterogeneity across studies and wide prediction intervals suggested substantial variability in model responses to immunotherapy. Univariable and multivariable meta-regressions failed to significantly explain this heterogeneity, suggesting additional factors may influence outcomes. Trim-and-fill and Egger's regression tests indicated funnel plot asymmetry, implying potential publication bias and small study effects. While our analysis demonstrated positive effects of immunotherapy on MBC and highlighted variability in animal tumor models, addressing model-related heterogeneity and enhancing methodological transparency are essential to improve reproducibility and clinical translatability.

Molecular probes for in vivo optical imaging of immune cells

Advancing the understanding of the various roles and components of the immune system requires sophisticated methods and technology for the detection of immune cells in their natural states. Recent advancements in the development of molecular probes for optical imaging have paved the way for non-invasive visualization and real-time monitoring of immune responses and functions. Here we discuss recent progress in the development of molecular probes for the selective imaging of specific immune cells. We emphasize the design principles of the probes and their comparative performance when using various optical modalities across disease contexts. We highlight molecular probes for imaging tumour-infiltrating immune cells, and their applications in drug screening and in the prediction of therapeutic outcomes of cancer immunotherapies. We also discuss the use of these probes in visualizing immune cells in atherosclerosis, lung inflammation, allograft rejection and other immune-related conditions, and the translational opportunities and challenges of using optical molecular probes for further understanding of the immune system and disease diagnosis and prognosis.

Cancer mRNA vaccines: clinical application progress and challenges

Messenger RNA (mRNA) vaccines have emerged as one of the most promising and rapidly evolving immunotherapeutic approaches due to their ease of production, demonstrated clinical efficacy, and high safety. The coronavirus disease 2019(COVID-19) pandemic has showcased the remarkable therapeutic potential of mRNA vaccines, prompting researchers to explore their use for cancer treatment. Preclinical studies and human clinical trials have indicated their substantial clinical applicability. However, current research faces several challenges, including the complexity of tumor antigen selection, vaccine stability, and the development of resistance. This review summarizes the optimization strategies for cancer mRNA vaccines in preclinical settings, the progress of clinical trials, and the challenges encountered while analyzing various delivery vehicle types, infusion methods, and application cases across different cancer types, highlighting key factors in vaccine design. The findings demonstrate that mRNA vaccines elicit specific immune responses and exhibit favorable safety and tolerability in clinical trials. Moreover, developing personalized neoantigen vaccines offers a novel direction for cancer immunotherapy. The unique contribution of this review lies in its comprehensive overview of the latest advancements in therapeutic mRNA vaccines for cancer treatment while identifying critical areas for future research to propel the field forward.

The SRG RAT® supports human cell xenotransplantation through enhanced tumor microenvironment interactions

The use of immunodeficient mice for human tumor engraftment is an essential model of human cancer, with uses ranging from basic science to translational research. However, low engraftment rates, slow growth, and smaller tumor volumes can be limitations. Previously, we reported a highly immunodeficient rat strain with the functional deletion of both the Rag2 and Il2rg genes on the Sprague-Dawley background ( SRG RAT ® ), which lacks B, T, and NK cells. Here, we subcutaneously engrafted two cell-derived xenograft (CDX) and seven patient-derived xenograft (PDX) models, including prostate, lung, ovarian, and uterine cancer models, into the SRG rat or NSG mouse models and tracked tumor growth. In all cases, the engraftment and tumor growth rates were better supported in the SRG rat compared to the NSG mouse. Interestingly, the SRG rat is not more immunocompromised than the NSG mouse, suggesting alternative mechanisms leading to the supportive growth in the SRG rat. Therefore, we explored potential differences in the tumor microenvironment (TME) between models grown in the two host animals. Lung PDX models grown in SRG rats showed enhanced formation of vasculature and stroma and were morphologically more consistent with the originating patient tumors. IHC analysis of the NCI-H660 CDX model showed differences in the tumors' stroma, vasculature, and macrophages when grown in the two host species. Single-cell spatial imaging of engrafted tumors showed upregulation of the human CXCL2 and TCIM in NCI-H660 tumors grown in the SRG rat versus the NSG mouse, both of which have been linked to poor prognosis in cancer. Combined, our data demonstrate that the SRG rat supports the growth of multiple human cancer types and displays enhanced tumor microenvironment interactions compared to NSG mice.

Can Humanized Immune System Mouse and Rat Models Accelerate the Development of Cytomegalovirus-Based Vaccines Against Infectious Diseases and Cancers?

Over the past three decades, immunodeficient mouse models carrying human immune cells, with or without human lymphoid tissues, termed humanized immune system (HIS) rodent models, have been developed to recapitulate the human immune system and associated immune responses. HIS mouse models have successfully modeled many human-restricted viral infections, including those caused by human cytomegalovirus (HCMV) and human immunodeficiency virus (HIV). HIS mouse models have also been used to model human cancer immunobiology, which exhibits differences from murine cancers in traditional mouse models. Variants of HIS mouse models that carry human liver cells, lung tissue, skin tissue, or human patient-derived tumor xenografts and human hematopoietic stem cells-derived-human immune cells with or without lymphoid tissue xenografts have been developed to probe human immune responses to infections and human tumors. HCMV-based vaccines are human-restricted, which poses limitations for mechanistic and efficacy studies using traditional animal models. The HCMV-based vaccine approach is a promising vaccine strategy as it induces robust effector memory T cell responses that may be critical in preventing and rapidly controlling persistent viral infections and cancers. Here, we review novel HIS mouse models with robust human immune cell development and primary and secondary lymphoid tissues that could address many of the limitations of HIS mice in their use as animal models for HCMV-based vaccine research. We also reviewed novel HIS rat models, which could allow long-term (greater than one year) vaccinology studies and better recapitulate human pathophysiology. Translating laboratory research findings to clinical application is a significant bottleneck in vaccine development; HIS rodents and related variants that more accurately model human immunology and diseases could increase the translatability of research findings.

Discovery and preclinical development of a SdAb-based CAR-T technology for targeting CD33 in AML

Chimeric antigen receptor T cell (CAR-T) therapies have revolutionized cancer immunotherapy. Traditional single-chain variable fragments (ScFvs) used as CAR recognition moieties face challenges such as high tonic signaling, compromised binding epitopes, and suboptimal affinity. Single-domain antibodies (SdAbs) offer an attractive alternative due to their smaller size, stability, and reduced immunogenicity. In this work, we developed an SdAb-CAR-T cell discovery platform integrating generation, characterization, and selection of SdAbs based on various properties. This approach was demonstrated by developing CAR-T cells with SdAbs against CD33, a target for acute myeloid leukemia (AML). We identified diverse SdAbs against CD33, with affinities ranging from 3.9-115 nM, and characterized their binding kinetics and epitope recognition. Using SdAb-based second-generation CARs, we assessed tonic signaling, T cell phenotypes, cytotoxicity and cytokine release in vitro, resulting in reduced tonic signaling and increased cytokine production. In vivo, SdAb-based CAR-T cells exhibited enhanced efficacy at lower doses, in a xenograft AML mouse model, demonstrating advantages over ScFv-based CD33 CAR-T cells.

Differences in treatment outcome between translational platforms in developing therapies for gastrointestinal cancers

The variability in translational models profoundly impacts the outcomes and predictive value of preclinical studies for gastrointestinal (GI) cancer treatments. Preclinical models, including 2D cell cultures, 3D organoids, patient-derived xenografts (PDXs), and animal models, provide distinct advantages and limitations in replicating the complex tumor microenvironment (TME) of human cancers. Each model's unique biological and structural differences contribute to discrepancies in treatment responses, challenging the direct translation of experimental results to clinical settings. While 2D cell cultures are cost-effective and suitable for high-throughput screening, they lack the 3D architecture and cellular interactions of the in vivo TME. Organoids offer a more comprehensive 3D structure that better mirrors tumor heterogeneity, yet they still face limitations in fully mimicking in vivo conditions, such as vascularization and immune cell interactions. PDXs, although more representative of human cancers due to their genetic fidelity and TME preservation, are costly and resource-intensive, with human stromal and immune components gradually replaced by murine counterparts over time. This review assesses the strengths and limitations of each model, highlighting recent advancements in translational platforms that incorporate complex TME features. Understanding the influence of model selection on treatment efficacy predictions is essential for enhancing the reliability of preclinical findings and advancing personalized therapeutic strategies for GI cancers.

A versatile mouse model to advance human microglia transplantation research in neurodegenerative diseases

BACKGROUND

Recent studies highlight the critical role of microglia in neurodegenerative disorders, and emphasize the need for humanized models to accurately study microglial responses. Human-mouse microglia xenotransplantation models are a valuable platform for functional studies and for testing therapeutic approaches, yet currently those models are only available for academic research. This hampers their implementation for the development and testing of medication that targets human microglia.

METHODS

We developed the hCSF1Bdes mouse line, which is suitable as a new transplantation model and available to be crossed to any disease model of interest. The hCSF1Bdes model created by CRISPR gene editing is RAG2 deficient and expresses human CSF1. Additionally, we crossed this model with two humanized App KI mice, the AppHu and the AppSAA. Flow cytometry, immunohistochemistry and bulk sequencing was used to study the response of microglia in the context of Alzheimer's disease.

RESULTS

Our results demonstrate the successful transplantation of iPSC-derived human microglia into the brains of hCSF1Bdes mice without triggering a NK-driven immune response. Furthermore, we confirmed the multipronged response of microglia in the context of Alzheimer's disease. The hCSF1Bdes and the crosses with the Alzheimer's disease knock-in model AppSAA and the humanized App knock-in control mice, AppHu are deposited with EMMA and fully accessible to the research community.

CONCLUSION

The hCSF1Bdes mouse is available for both non-profit and for-profit organisations, facilitating the use of the xenotransplantation paradigm for human microglia to study complex human disease.

Pre-clinical safety and efficacy of human induced pluripotent stem cell-derived products for autologous cell therapy in Parkinson's disease

Human induced pluripotent stem cell (hiPSC)-derived midbrain dopaminergic cells (mDACs) represent a promising source for autologous cell therapy in Parkinson's disease (PD), but standardized regulatory criteria are essential for clinical translation. In this pre-clinical study, we generated multiple clinical-grade hiPSC lines from freshly biopsied fibroblasts of four sporadic PD patients using episomal reprogramming and differentiated them into mDACs using a refined 21-day protocol. Rigorous evaluations included whole-genome/exome sequencing, RNA sequencing, and in vivo studies, including a 39-week Good Laboratory Practice-compliant mouse safety study. While mDACs from all lines met safety criteria, mDACs from one patient failed to improve rodent behavioral outcomes, underscoring inter-individual variability. Importantly, in vitro assessments did not reliably predict in vivo efficacy, identifying dopaminergic fiber density as a key efficacy criterion. These findings support comprehensive quality control guidelines for autologous cell therapy and pave the way for a clinical trial with eight sporadic PD patients, scheduled to commence in 2025.

A novel SIV-infection animal model based on nude mice inoculated with MT-2 cells

To establish a novel murine model conducive to simian immunodeficiency virus (SIV) replication in vivo, male BALB/c nude mice, aged three weeks, were administered a single intraperitoneal inoculation of SIV-infected MT-2 cells (derived from human T-cell leukemia). Subsequently, alterations in plasma viral load and the engraftment of MT-2 cells in vivo were examined, while immunological changes were assessed via ELISA and flow cytometry analysis. All of the mice in the experimental group exhibited detectable plasma viral loads in their peripheral circulation, largely due to the proliferation of SIV-infected MT-2 cells within the T-cell-deficient environment of nude mice, resulting in colonization of the abdominal cavity and lymph nodes and the subsequent release of free virions to perpetuate the infection. Mice that received highly active anti-retroviral therapy (HAART) treatment demonstrated a statistically significant reduction in plasma viral loads, with HAART administration partially reversing the course of SIV-induced immune dysfunction. Therefore, the model presented in this study offers substantial potential as a robust tool for evaluating antiviral efficacy and immune modulation in an in vivo setting.

Inflammatory responses revealed through HIV infection of microglia-containing cerebral organoids

Cerebral organoids (COs) are valuable tools for studying the intricate interplay between glial cells and neurons in brain development and disease, including HIV-associated neuroinflammation. We developed a novel approach to generate microglia containing COs (CO-iMs) by co-culturing hematopoietic progenitors and inducing pluripotent stem cells. This approach allowed for the differentiation of microglia within the organoids concomitantly with the neuronal progenitors. Compared with conventional COs, CO-iMs were more efficient at generating CD45+/CD11b+/Iba-1+ microglia and presented a physiologically relevant proportion of microglia (~ 7%). CO-iMs presented substantially increased expression of microglial homeostatic and sensome markers as well as markers for the complement cascade. CO-iMs are susceptible to HIV infection, resulting in a significant increase in several pro-inflammatory cytokines/chemokines, which are abrogated by the addition of antiretrovirals. Thus, CO-iM is a robust model for deciphering neuropathogenesis, neuroinflammation, and viral infections of brain cells in a 3D culture system.

A Novel Immunodeficient Hyperglycemic Mouse Carrying the Ins1 Akita Mutation for Xenogeneic Islet Cell Transplantation

BACKGROUND

For patients who have difficulty controlling blood glucose even with insulin administration, xenogeneic islet cells, including human stem cell-derived pancreatic islets (hSC-islet) and porcine islets, have garnered attention as potential solutions to challenges associated with donor shortages. For the development of diabetes treatment modalities that use cell transplantation therapy, it is essential to evaluate the efficacy and safety of transplanted cells using experimental animals over the long term.

METHODS

We developed permanent diabetic immune-deficient mice by introducing the Akita (C96Y) mutation into the rodent-specific Insulin1 gene of NOD/Shi-scid IL2rγc null (NOG) mice ( Ins1 C96Y/C96Y NOG). Their body weight, nonfasting blood glucose, and survival were measured from 4 wk of age. Insulin sensitivity was assessed via tolerance tests. To elucidate the utility of these mice in xenotransplantation experiments, we transplanted hSC-islet cells or porcine islets under the kidney capsules of these mice.

RESULTS

All male and female homozygous mice exhibited persistent severe hyperglycemia associated with β-cell depletion as early as 4 wk of age and exhibited normal insulin sensitivity. These mice could be stably engrafted with hSC-islets, and the mice that received porcine islet grafts promptly exhibited lowered blood glucose levels, maintaining blood glucose levels below the normal glucose range for at least 52 wk posttransplantation.

CONCLUSIONS

The Ins1C96Y/C96Y NOG mouse model provides an effective platform to assess both the efficacy and safety of long-term xenograft engraftment without the interference of their immune responses. This study is expected to contribute essential basic information for the clinical application of islet cell transplantation.

Donor MHC-specific thymus vaccination allows for immunocompatible allotransplantation

Organ transplantation is the last-resort option to treat organ failure. However, less than 10% of patients benefit from this only option due to lack of major histocompatibility complex (MHC)-matched donor organs and 25%-80% of donated organs could not find MHC-matched recipients. T cell allorecognition is the principal mechanism for allogeneic graft rejection. We herein present a "donor MHC-specific thymus vaccination" (DMTV) strategy to induce T cell tolerance to both autologous and allogeneic donor MHC. Allogeneic MHC molecules were expressed in the recipient thymus through adeno-associated virus-mediated delivery, which led to stable expression of allogeneic MHC together with the autologous MHC in the engineered thymus. During local T cell education, those T cells recognizing either autologous MHC or allogeneic MHC were equally depleted. We constructed C57BL/6-MHC and BALB/c-MHC dual immunocompatible mice via thymus vaccination of C57BL/6-MHC into the BALB/c thymus and observed long-term graft tolerance after transplantation of C57BL/6 skin and C57BL/6 mouse embryonic stem cells into the vaccinated BALB/c mice. We also validated our DMTV strategy in a bone marrow, liver, thymus (BLT)-humanized mouse model for immunocompatible allotransplantation of human embryonic stem cells. Our study suggests that the DMTV strategy is a potent avenue to introduce a donor compatible immune system in recipients, which overcomes the clinical dilemma of the extreme shortage of MHC-matched donor organs for treating patients with end-stage organ failure.

LLT1 overexpression renders allogeneic-NK resistance and facilitates the generation of enhanced universal CAR-T cells

BACKGROUND

The benefit of universal CAR-T cells over autologous CAR-T cell therapy is that they are a treatment that is ready to use. However, the prevention of graft-versus-host disease (GVHD) and host-versus-graft reaction (HVGR) remains challenging. Deleting class I of human leukocyte antigen (HLA-I) and class II of human leukocyte antigen (HLA-II) can prevent rejection by allogeneic T cells; however, natural killer (NK) cell rejection due to the loss of self-recognition remains unresolved. This study tested whether the overexpression of Lectin-like transcript 1 (LLT1), an NK cell inhibitory ligand, in T cell receptor (TCR) and HLA-I/II disrupted universal CD38-targeting CAR-T cells could prevent rejection by allogeneic NK cells.

METHODS

We generated CD38-targeting universal CAR-T cells by transducing T cells with lentiviruses encoding the CD38 CAR and LLT1 constructs. T cells were subjected to CD38, TCR, HLA-I, and HLA-II gene knockdown using CRISPR/Cas9, followed by lentiviral transduction. We performed cytotoxicity, proliferation, and cytokine assays to evaluate the functionality of universal chimeric antigen receptor-T cell (UCAR-T) cells and conducted in vitro and in vivo assays, including allogeneic responses and RNA sequencing, to assess their resistance to allogeneic T and NK cells, anti-leukemia efficacy, and persistence in treating hematologic malignancies.

RESULTS

Genetic editing of CD38 universal CAR-T cells, including CD38, T cell receptor alpha constant (TRAC), beta-2-microglobulin (B2M), and class II major histocompatibility complex transactivator (CIITA) knockdowns, was successfully achieved. In vitro, LLT1 overexpression boosted CAR-T cell proliferation and antitumor activity, leading to a transcriptional signature characterized by elevated stemness-related markers (SELL, BCL6, TCF7, and CD27) and increased levels of IL-10 and other cytokines. It also effectively mitigates rejection by allogeneic NK and T cells. In a humanized T-cell acute lymphoblastic leukemia (T-ALL) model, CD38 allogeneic universal CAR-T cells demonstrated superior survival rates and tumor clearance with reduced inflammatory responses.

CONCLUSION

According to these results, LLT1 overexpression enhances UCAR-T cell activity and prevents allogeneic rejection, providing essential insights for the development of universal CAR-T cell therapy.

Human PBMC-based humanized mice exhibit myositis features and serve as a drug evaluation model

Idiopathic inflammatory myopathies (IIMs) are a group of autoimmune disorders characterized by immune cell infiltration of muscle tissue accompanied by inflammation. Treatment of IIMs is challenging, with few effective therapeutic options due to the lack of appropriate models that successfully recapitulate the features of IIMs observed in humans. In the present study, we demonstrate that immunodeficient mice transplanted with human peripheral blood mononuclear cells (hPBMCs) exhibit the key pathologic features of myositis observed in humans and develop graft-versus-host disease. The hPBMC mice exhibit elevated serum levels of creatine kinase and aspartate transaminase, markers of myositis, and increased expression levels of myositis-related genes, such as vascular cell adhesion molecule 1, intercellular adhesion molecule 1, and serum amyloid A1, in muscle tissues. Histopathologic and flow cytometric analyses reveal the infiltration of CD8+ T cells in the muscle tissue of hPBMC mice, similar to that observed in patients with myositis, particularly in those with polymyositis. Transplantation of CD8+ T cell-depleted hPBMC leads to a significant reduction in polymyositis-like symptoms, in agreement with previous studies demonstrating CD8+ T cells as the main pathologic drivers of polymyositis. Furthermore, the transcriptome analysis of muscle tissue from hPBMC mice reveal extensive upregulation of characteristic genes of polymyositis, providing further support that hPBMC mice accurately reflect the pathophysiology of myositis in humans. Finally, administration of prednisolone or tacrolimus, which are commonly used for IIM treatment, leads to significant alleviation of myositis findings. Therefore, we propose that hPBMC mice should be considered as a model that accurately reflects the pathophysiology of myositis in human patients.

Harnessing cellular therapeutics for type 1 diabetes mellitus: progress, challenges, and the road ahead

Type 1 diabetes mellitus (T1DM) is a growing global health concern that affects approximately 8.5 million individuals worldwide. T1DM is characterized by an autoimmune destruction of pancreatic β cells, leading to a disruption in glucose homeostasis. Therapeutic intervention for T1DM requires a complex regimen of glycaemic monitoring and the administration of exogenous insulin to regulate blood glucose levels. Advances in continuous glucose monitoring and algorithm-driven insulin delivery devices have improved the quality of life of patients. Despite this, mimicking islet function and complex physiological feedback remains challenging. Pancreatic islet transplantation represents a potential functional cure for T1DM but is hindered by donor scarcity, variability in harvested cells, aggressive immunosuppressive regimens and suboptimal clinical outcomes. Current research is directed towards generating alternative cell sources, improving transplantation methods, and enhancing cell survival without chronic immunosuppression. This Review maps the progress in cell replacement therapies for T1DM and outlines the remaining challenges and future directions. We explore the state-of-the-art strategies for generating replenishable β cells, cell delivery technologies and local targeted immune modulation. Finally, we highlight relevant animal models and the regulatory aspects for advancing these technologies towards clinical deployment.

A novel anti-CD47 antibody with therapeutic potential for NK/T-cell lymphoma

NK/T-cell lymphoma (NKTCL) is a rare type of non-Hodgkin lymphoma (NHL). Although L-asparaginase-based chemotherapy has significantly improved survival in early-stage patients, the prognosis is poor in advanced and relapsed or refractory patients. CD47 is a promising target for cancer immunotherapy. However, the expression of CD47 in NKTCL and the antitumor effect and mechanism of the anti-CD47 monoclonal antibody (mAb) AK117 in NKTCL remain unclear. Firstly, the expression level of CD47 protein in NKTCL cells was detected by immunoblot and flow cytometry. Secondly, in order to validate the role of CD47 downregulation in the proliferation, apoptosis, and cell cycle of NKTCL cells, we used shRNA transfection to knock down CD47 expression. We determined the effect of knocking down CD47 and the novel anti-CD47 antibody AK117 on the phagocytosis of NKYS and YTS cells by M2 macrophages in vitro. Finally, we assessed the ability of AK117 to inhibit tumor growth in an NKTCL xenograft model in which YTS cells were engrafted in SCID mice. The results showed that CD47 is relatively highly expressed in NKTCL cells. CD47 knockdown in NKTCL promoted phagocytosis by M2 macrophages in an in vitro coculture assay. The study also demonstrated that anti-CD47 mAb AK117 promoted phagocytosis of NKTCL cells by M2 macrophages. In addition, in vivo experiments showed that the anti-CD47 mAb AK117 significantly inhibited the growth of subcutaneous xenograft tumors in SCID mice compared to the control antibody IgG. Our results indicate that targeting CD47 monoclonal antibodies is a potential therapeutic strategy for NKTCL.

Challenges in establishing small animal models for Ancylostoma caninum : Host specificity and resistance to infection in rodent hosts

This study explores potential small animal models for the dog hookworm, Ancylostoma caninum , a parasitic nematode which has repeatedly exhibited the ability to develop resistance to a range of anthelmintics. Immunomodulated hamsters, gerbils, rats, and mice were infected with A. caninum. Despite varying degrees of immunosuppression, and in some cases, total adaptive immunodeficiency, no adult worms were recovered, and larval arrest (L3 stage) occurred in muscle tissue of mice and hamsters. This highlights the strict host specificity of A. caninum and emphasizes the challenges of developing rodent models usable for anthelmintic testing with a strict specialist parasite.

Cas9 editing of ATXN1 in a spinocerebellar ataxia type 1 mice and human iPSC-derived neurons

Spinocerebellar ataxia type 1 (SCA1) is an adult-onset neurodegenerative disease caused by an expansion of the CAG repeat region of the ATXN1 gene. Currently there are no disease-modifying treatments; however, previous work has shown the potential of gene therapy, specifically RNAi, as a potential modality. Cas9 editing offers potential for these patients but has yet to be evaluated in SCA1 models. To test this, we first characterized the number of transgenes harbored in the common B05 mouse model of SCA1. Despite having five copies of the human mutant transgene, a 20% reduction of ATXN1 improved behavior deficits without increases in inflammatory markers. Importantly, the editing approach was confirmed in induced pluripotent stem cell (iPSC) neurons derived from patients with SCA1, promoting the translatability of the approach to patients.

Primary Bone Tumors and Breast Cancer-Induced Bone Metastases: In Vivo Animal Models and New Alternative Approaches

Bone is the preferential site of metastasis for the most common tumors, including breast cancer. On the other hand, osteosarcoma is the primary bone cancer that most commonly occurs and causes bone cancer-related deaths in children. Several treatment strategies have been developed so far, with little or no efficacy for patient survival and with the development of side effects. Therefore, there is an urgent need to develop more effective therapies for bone primary tumors and bone metastatic disease. This almost necessarily requires the use of in vivo animal models that better mimic human pathology and at the same time follow the ethical principles for the humane use of animal testing. In this review we aim to illustrate the main and more suitable in vivo strategies employed to model bone metastases and osteosarcoma. We will also take a look at the recent technologies implemented for a partial replacement of animal testing.

Predicting clinical trial success for Clostridium difficile infections based on preclinical data

Preclinical models are ubiquitous and essential for drug discovery, yet our understanding of how well they translate to clinical outcomes is limited. In this study, we investigate the translational success of treatments for Clostridium difficile infection from animal models to human patients. Our analysis shows that only 36% of the preclinical and clinical experiment pairs result in translation success. Univariate analysis shows that the sustained response endpoint is correlated with translation failure (SRC = -0.20, p-value = 1.53 × 10-54), and explainability analysis of multi-variate random forest models shows that both sustained response endpoint and subject age are negative predictors of translation success. We have developed a recommendation system to help plan the right preclinical study given factors such as drug dosage, bacterial dosage, and preclinical/clinical endpoint. With an accuracy of 0.76 (F1 score of 0.71) and by using only 7 features (out of 68 total), the proposed system boosts translational efficiency by 25%. The method presented can extend to any disease and can serve as a preclinical to clinical translation decision support system to accelerate drug discovery and de-risk clinical outcomes.

Xianling Lianxia formula improves the efficacy of trastuzumab by enhancing NK cell-mediated ADCC in HER2-positive BC

Trastuzumab has improved survival rates in human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC), but drug resistance leads to treatment failure. Natural killer (NK) cell-mediated antibody-dependent cell cytotoxicity (ADCC) represents an essential antitumor immune mechanism of trastuzumab. Traditional Chinese medicine (TCM) has been used for centuries to treat diseases because of its capacity to improve immune responses. Xianling Lianxia formula (XLLXF), based on the principle of "strengthening body and eliminating toxin", exhibits a synergistic effect in the trastuzumab treatment of patients with HER2-positive BC. Notably, this synergistic effect of XLLXF was executed by enhancing NK cells and ADCC, as demonstrated through in vitro co-culture of NK cells and BC cells and in vivo intervention experiments. Mechanistically, the augmented impact of XLLXF on NK cells is linked to a decrease in cytokine inducible Src homology 2 (SH2) containing protein (CISH) expression, which in turn activates the Janus kinase 1 (JAK1)/signal transducer and activator of transcription 5 (STAT5) pathway. Collectively, these findings suggested that XLLXF holds promise for enhancing NK cell function and sensitizing patients with HER2-positive BC to trastuzumab.

Efficient generation of human immune system rats using human CD34+ cells

Human immune system (HIS) mice generated using human CD34+ hematopoietic stem cells serve as a pivotal model for the in vivo evaluation of immunotherapies for humans. Yet, HIS mice possess certain limitations. Rats, due to their size and comprehensive immune system, hold promise for translational experiments. Here, we describe an efficacious method for long-term immune humanization, through intrahepatic injection of hCD34+ cells in newborn immunodeficient rats expressing human SIRPα. In contrast to HIS mice and similar to humans, HIS rats showed in blood a predominance of T cells, followed by B cells. Immune humanization was also high in central and secondary lymphoid organs. HIS rats treated with the anti-human CD3 antibody were depleted of human T cells, and human cytokines were detected in sera. We describe for the first time a method to efficiently generate HIS rats. HIS rats have the potential to be a useful model for translational immunology.

Human-mouse chimeric brain models constructed from iPSC-derived brain cells: Applications and challenges

The establishment of reliable human brain models is pivotal for elucidating specific disease mechanisms and facilitating the discovery of novel therapeutic strategies for human brain disorders. Human induced pluripotent stem cell (iPSC) exhibit remarkable self-renewal capabilities and can differentiate into specialized cell types. This makes them a valuable cell source for xenogeneic or allogeneic transplantation. Human-mouse chimeric brain models constructed from iPSC-derived brain cells have emerged as valuable tools for modeling human brain diseases and exploring potential therapeutic strategies for brain disorders. Moreover, the integration and functionality of grafted stem cells has been effectively assessed using these models. Therefore, this review provides a comprehensive overview of recent progress in differentiating human iPSC into various highly specialized types of brain cells. This review evaluates the characteristics and functions of the human-mouse chimeric brain model. We highlight its potential roles in brain function and its ability to reconstruct neural circuitry in vivo. Additionally, we elucidate factors that influence the integration and differentiation of human iPSC-derived brain cells in vivo. This review further sought to provide suitable research models for cell transplantation therapy. These research models provide new insights into neuropsychiatric disorders, infectious diseases, and brain injuries, thereby advancing related clinical and academic research.

Lymphotoxin-β promotes breast cancer bone metastasis colonization and osteolytic outgrowth

Bone metastasis is a lethal consequence of breast cancer. Here we used single-cell transcriptomics to investigate the molecular mechanisms underlying bone metastasis colonization-the rate-limiting step in the metastatic cascade. We identified that lymphotoxin-β (LTβ) is highly expressed in tumour cells within the bone microenvironment and this expression is associated with poor bone metastasis-free survival. LTβ promotes tumour cell colonization and outgrowth in multiple breast cancer models. Mechanistically, tumour-derived LTβ activates osteoblasts through nuclear factor-κB2 signalling to secrete CCL2/5, which facilitates tumour cell adhesion to osteoblasts and accelerates osteoclastogenesis, leading to bone metastasis progression. Blocking LTβ signalling with a decoy receptor significantly suppressed bone metastasis in vivo, whereas clinical sample analysis revealed significantly higher LTβ expression in bone metastases than in primary tumours. Our findings highlight LTβ as a bone niche-induced factor that promotes tumour cell colonization and osteolytic outgrowth and underscore its potential as a therapeutic target for patients with bone metastatic disease.

Testosterone supplementation increases red blood cell susceptibility to oxidative stress, decreases membrane deformability, and decreases survival after cold storage and transfusion

BACKGROUND

Blood collection from donors on testosterone therapy (TT) is restricted to red blood cell (RBC) concentrates to avoid patient exposure to supraphysiological testosterone (T). The objective of this study was to identify TT-related changes in RBC characteristics relevant to transfusion effectiveness in patients.

STUDY DESIGN

This was a two-part study with cohorts of patients and blood donors on TT. In part 1, we conducted longitudinal evaluation of RBCs collected before and at three time points after initiation of T. RBC assays included storage and oxidative hemolysis, membrane deformability (elongation index), and oximetry. In part 2, we evaluated the fate of transfused RBCs from TT donors in immunodeficient mice and by retrospective analyses of NIH's vein-to-vein databases.

RESULTS

TT increased oxidative hemolysis (1.45-fold change) and decreased RBC membrane deformability. Plasma free testosterone was positively correlated with oxidative hemolysis (r = .552) and negatively correlated with the elongation index (r = -.472). Stored and gamma-irradiated RBCs from TT donors had lower posttransfusion recovery in mice compared to controls (41.6 ± 12 vs. 55.3 ± 20.5%). Recipients of RBCs from male donors taking T had 25% lower hemoglobin increments compared to recipients of RBCs from non-TT male donors, and had increased incidence (OR, 1.80) of requiring additional RBC transfusions within 48 h of the index transfusion event.

CONCLUSIONS

TT is associated with altered RBC characteristics and transfusion effectiveness. These results suggest that clinical utilization of TT RBCs may be less effective in recipients who benefit from longer RBC survival, such as chronically transfused patients.

Epizootic of enterocolitis and clostridial overgrowth in NSG and NSG-related mouse strains

While the immunodeficient status of NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) and NSG-related mice provides utility for numerous research models, it also results in increased susceptibility to opportunistic pathogens. Over a 9-week period, a high rate of mortality was reported in a housing room of NSG and NSG-related mice. Diagnostics were performed to determine the underlying etiopathogenesis. Mice submitted for evaluation included those found deceased (n = 2), cage mates of deceased mice with or without diarrhea (n = 17), and moribund mice (n = 8). Grossly, mice exhibited small intestinal and cecal dilation with abundant gas and/or digesta (n = 18), serosal hemorrhage and congestion (n = 6), or were grossly normal (n = 3). Histologically, there was erosive to ulcerative enterocolitis (n = 7) of the distal small and large intestine or widespread individual epithelial cell death with luminal sloughing (n = 13) and varying degrees of submucosal edema and mucosal hyperplasia. Cecal dysbiosis, a reduction in typical filamentous bacteria coupled with overgrowth of bacterial rods, was identified in 18 of 24 (75%) mice. Clostridium spp. and Paeniclostridium sordellii were identified in 13 of 23 (57%) and 7 of 23 (30%) mice, respectively. Clostridium perfringens (7 of 23, 30%) was isolated most frequently. Toxinotyping of C. perfringens positive mice (n = 2) identified C. perfringens type A. Luminal immunoreactivity to several clostridial species was identified within lesioned small intestine by immunohistochemistry. Clinicopathologic findings were thus associated with overgrowth of various clostridial species, though direct causality could not be ascribed. A diet shift preceding the mortality event may have contributed to loss of intestinal homeostasis.

Patient-Derived-Xenografts in Mice: A Preclinical Platform for Cancer Research

The use of patient-derived xenografts (PDXs) has dramatically improved drug development programs. PDXs (1) reproduce the pathological features and the genomic profile of the parental tumors more precisely than other preclinical models, and (2) more faithfully predict therapy response. However, PDXs have limitations. These include the inability to completely capture tumor heterogeneity and the role of the immune system, the low engraftment efficiency of certain tumor types, and the consequences of the human-host interactions. Recently, the use of novel mouse strains and specialized engraftment techniques has enabled the generation of "humanized" PDXs, partially overcoming such limitations. Importantly, establishing, characterizing, and maintaining PDXs is costly and requires a significant regulatory, administrative, clinical, and laboratory infrastructure. In this review, we will retrace the historical milestones that led to the implementation of PDXs for cancer research, review the most recent innovations in the field, and discuss future avenues to tackle deficiencies that still exist.

HIV-1 infection promotes neuroinflammation and neuron pathogenesis in novel microglia-containing cerebral organoids

Cerebral organoids (COs) are a valuable tool to study the intricate interplay between glial cells and neurons in brain development and disease, including HIV-associated neuroinflammation. We developed a novel approach to generate microglia containing COs (CO-iMs) by co-culturing hematopoietic progenitors and induced pluripotent stem cells. This approach allowed for the differentiation of microglia within the organoids concomitantly to the neuronal progenitors. CO- iMs exhibited higher efficiency in generation of CD45 + /CD11b + /Iba-1 + microglia cells compared to conventional COs with physiologically relevant proportion of microglia (∼7%). CO-iMs exhibited substantially higher expression of microglial homeostatic and sensome markers as well as markers for the complement cascade. CO-iMs showed susceptibility to HIV infection resulting in a significant increase in several pro-inflammatory cytokines/chemokines and compromised neuronal function, which were abrogated by addition of antiretrovirals. Thus, CO-iM is a robust model to decipher neuropathogenesis, neurological disorders, and viral infections of brain cells in a 3D culture system.

Engineering CD3/CD137 Dual Specificity into a DLL3-Targeted T-Cell Engager Enhances T-Cell Infiltration and Efficacy against Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is an aggressive cancer for which immune checkpoint inhibitors (ICI) have had only limited success. Bispecific T-cell engagers are promising therapeutic alternatives for ICI-resistant tumors, but not all patients with SCLC are responsive. Herein, to integrate CD137 costimulatory function into a T-cell engager format and thereby augment therapeutic efficacy, we generated a CD3/CD137 dual-specific Fab and engineered a DLL3-targeted trispecific antibody (DLL3 trispecific). The CD3/CD137 dual-specific Fab was generated to competitively bind to CD3 and CD137 to prevent DLL3-independent cross-linking of CD3 and CD137, which could lead to systemic T-cell activation. We demonstrated that DLL3 trispecific induced better tumor growth control and a marked increase in the number of intratumoral T cells compared with a conventional DLL3-targeted bispecific T-cell engager. These findings suggest that DLL3 trispecific can exert potent efficacy by inducing concurrent CD137 costimulation and provide a promising therapeutic option for SCLC.

The Intersection of HIV and Pulmonary Vascular Health: From HIV Evolution to Vascular Cell Types to Disease Mechanisms

People living with HIV (PLWH) face a growing burden of chronic diseases, owing to the combinations of aging, environmental triggers, lifestyle choices, and virus-induced chronic inflammation. The rising incidence of pulmonary vascular diseases represents a major concern for PLWH. The study of HIV-associated pulmonary vascular complications ideally requires a strong understanding of pulmonary vascular cell biology and HIV pathogenesis at the molecular level for effective applications in infectious diseases and vascular medicine. Active HIV infection and/or HIV proteins disturb the delicate balance between vascular tone and constriction, which is pivotal for maintaining pulmonary vascular health. One of the defining features of HIV is its high genetic diversity owing to several factors including its high mutation rate, recombination between viral strains, immune selective pressures, or even geographical factors. The intrinsic HIV genetic diversity has several important implications for pathogenic outcomes of infection and the overall battle to combat HIV. Challenges in the field present themselves from two sides of the same coin: those imposed by the virus itself and those stemming from the host. The field may be advanced by further developing in vivo and in vitro models that are well described for both pulmonary vascular diseases and HIV for mechanistic studies. In essence, the study of HIV-associated pulmonary vascular complications requires a multidisciplinary approach, drawing upon insights from both infectious diseases and vascular medicine. In this review article, we discuss the fundamentals of HIV virology and their impact on pulmonary disease, aiming to enhance the understanding of either area or both simultaneously. Bridging the gap between preclinical research findings and clinical practice is essential for improving patient care. Addressing these knowledge gaps requires interdisciplinary collaborations, innovative research approaches, and dedicated efforts to prioritize HIV-related pulmonary complications on the global research agenda.

Bone formation by human paediatric marrow stromal cells in a functional allogeneic immune system

Allogeneic stem-cell based regenerative medicine is a promising approach for bone defect repair. The use of chondrogenically differentiated human marrow stromal cells (MSCs) has been shown to lead to bone formation by endochondral ossification in immunodeficient pre-clinical models. However, an insight into the interactions between the allogeneic immune system and the human MSC-derived bone grafts has not been fully achieved yet. The choice of a potent source of MSCs isolated from pediatric donors with consistent differentiation and high proliferation abilities, as well as low immunogenicity, could increase the chance of success for bone allografts. In this study, we employed an immunodeficient animal model humanised with allogeneic immune cells to study the immune responses towards chondrogenically differentiated human pediatric MSCs (ch-pMSCs). We show that ch-differentiated pMSCs remained non-immunogenic to allogeneic CD4 and CD8 T cells in an in vitro co-culture model. After subcutaneous implantation in mice, ch-pMSC-derived grafts were able to initiate bone mineralisation in the presence of an allogeneic immune system for 3 weeks without the onset of immune responses. Re-exposing the splenocytes of the humanised animals to pMSCs did not trigger further T cell proliferation, suggesting an absence of secondary immune responses. Moreover, ch-pMSCs generated mature bone after 8 weeks of implantation that persisted for up to 6 more weeks in the presence of an allogeneic immune system. These data collectively show that human allogeneic chondrogenically differentiated pediatric MSCs might be a safe and potent option for bone defect repair in the tissue engineering and regenerative medicine setting.

Humanized mouse models: A valuable platform for preclinical evaluation of human cancer

Animal models are routinely employed to assess the treatments for human cancer. However, due to significant differences in genetic backgrounds, traditional animal models are unable to meet bioresearch needs. To overcome this restriction, researchers have generated and optimized immunodeficient mice, and then engrafted human genes, cells, tissues, or organs in mice so that the responses in the model mice could provide a more reliable reference for treatments. As a bridge connecting clinical application and basic research, humanized mice are increasingly used in the preclinical evaluation of cancer treatments, particularly after gene interleukin 2 receptor gamma mutant mice were generated. Human cancer models established in humanized mice support exploration of the mechanism of cancer occurrence and provide an efficient platform for drug screening. However, it is undeniable that the further application of humanized mice still faces multiple challenges. This review summarizes the construction approaches for humanized mice and their existing limitations. We also report the latest applications of humanized mice in preclinical evaluation for the treatment of cancer and point out directions for future optimization of these models.

Animals in Respiratory Research

The respiratory barrier, a thin epithelial barrier that separates the interior of the human body from the environment, is easily damaged by toxicants, and chronic respiratory diseases are common. It also allows the permeation of drugs for topical treatment. Animal experimentation is used to train medical technicians, evaluate toxicants, and develop inhaled formulations. Species differences in the architecture of the respiratory tract explain why some species are better at predicting human toxicity than others. Some species are useful as disease models. This review describes the anatomical differences between the human and mammalian lungs and lists the characteristics of currently used mammalian models for the most relevant chronic respiratory diseases (asthma, chronic obstructive pulmonary disease, cystic fibrosis, pulmonary hypertension, pulmonary fibrosis, and tuberculosis). The generation of animal models is not easy because they do not develop these diseases spontaneously. Mouse models are common, but other species are more appropriate for some diseases. Zebrafish and fruit flies can help study immunological aspects. It is expected that combinations of in silico, in vitro, and in vivo (mammalian and invertebrate) models will be used in the future for drug development.

Dclre1c-Mutation-Induced Immunocompromised Mice Are a Novel Model for Human Xenograft Research

Severe combined immunodeficient (SCID) mice serve as a critical model for human xenotransplantation studies, yet they often suffer from low engraftment rates and susceptibility to graft-versus-host disease (GVHD). Moreover, certain SCID strains demonstrate 'immune leakage', underscoring the need for novel model development. Here, we introduce an SCID mouse model with a targeted disruption of the dclre1c gene, encoding Artemis, which is essential for V(D)J recombination and DNA repair during T cell receptor (TCR) and B cell receptor (BCR) assembly. Artemis deficiency precipitates a profound immunodeficiency syndrome, marked by radiosensitivity and compromised T and B lymphocyte functionality. Utilizing CRISPR/Cas9-mediated gene editing, we generated dclre1c-deficient mice with an NOD genetic background. These mice exhibited a radiosensitive SCID phenotype, with pronounced DNA damage and defective thymic, splenic and lymph node development, culminating in reduced T and B lymphocyte populations. Notably, both cell lines and patient-derived tumor xenografts were successfully engrafted into these mice. Furthermore, the human immune system was effectively rebuilt following peripheral blood mononuclear cells (PBMCs) transplantation. The dclre1c-knockout NOD mice described herein represent a promising addition to the armamentarium of models for xenotransplantation, offering a valuable platform for advancing human immunobiological research.

Characterization of Human Engraftment and Hemophagocytic Lymphohistiocytosis in NSG-SGM3 Neonate Mice Engrafted with Purified CD34+ Hematopoietic Stem Cells

Immunodeficient mice bearing human immune systems, or "humanized" chimeric mice, are widely used in basic research, along with the preclinical stages of drug development. Nonobese diabetic-severe combined immunodeficiency (NOD-SCID) IL2Rγnull (NSG) mice expressing human stem cell factor, granulocyte-macrophage colony stimulating factor, and interleukin-3 (NSG-SGM3) support robust development of human myeloid cells and T cells but have reduced longevity due to the development of fatal hemophagocytic lymphohistiocytosis (HLH). Here, we describe an optimized protocol for development of human immune chimerism in NSG-SGM3 mice. We demonstrate that efficient human CD45+ reconstitution can be achieved and HLH delayed by engraftment of neonatal NSG-SGM3 with low numbers of human umbilical cord-derived CD34+ hematopoietic stem cells in the absence of preconditioning irradiation.

Accelerated Neuroimmune Dysfunction in Aged HIV-1-Infected Humanized Mice

Disordered immunity, aging, human immunodeficiency virus type one (HIV-1) infection, and responses to antiretroviral therapy are linked. However, how each factor is linked with the other(s) remains incompletely understood. It has been reported that accelerated aging, advanced HIV-1 infection, inflammation, and host genetic factors are associated with host cellular, mitochondrial, and metabolic alterations. However, the underlying mechanism remains elusive. With these questions in mind, we used chronically HIV-1-infected CD34-NSG humanized mice (hu-mice) to model older people living with HIV and uncover associations between HIV-1 infection and aging. Adult humanized mice were infected with HIV-1 at the age of 20 weeks and maintained for another 40 weeks before sacrifice. Animal brains were collected and subjected to transcriptomics, qPCR, and immunofluorescence assays to uncover immune disease-based biomarkers. CD4+ T cell decline was associated with viral level and age. Upregulated C1QA, CD163, and CXCL16 and downregulated LMNA and CLU were identified as age-associated genes tied to HIV-1 infection. Ingenuity pathway analysis affirmed links to innate immune activation, pyroptosis signaling, neuroinflammation, mitochondrial dysfunction, cellular senescence, and neuronal dysfunction. In summary, CD34-NSG humanized mice are identified as a valuable model for studying HIV-1-associated aging. Biomarkers of immune senescence and neuronal signaling are both age- and virus-associated. By exploring the underlying biological mechanisms that are linked to these biomarkers, interventions for next generation HIV-1-infected patients can be realized.

Organoids: An Emerging Precision Medicine Model for Prostate Cancer Research

Prostate cancer (PCa) has been known as the most prevalent cancer disease and the second leading cause of cancer mortality in men almost all over the globe. There is an urgent need for establishment of PCa models that can recapitulate the progress of genomic landscapes and molecular alterations during development and progression of this disease. Notably, several organoid models have been developed for assessing the complex interaction between PCa and its surrounding microenvironment. In recent years, PCa organoids have been emerged as powerful in vitro 3D model systems that recapitulate the molecular features (such as genomic/epigenomic changes and tumor microenvironment) of PCa metastatic tumors. In addition, application of organoid technology in mechanistic studies (i.e., for understanding cellular/subcellular and molecular alterations) and translational medicine has been recognized as a promising approach for facilitating the development of potential biomarkers and novel therapeutic strategies. In this review, we summarize the application of PCa organoids in the high-throughput screening and establishment of relevant xenografts for developing novel therapeutics for metastatic, castration resistant, and neuroendocrine PCa. These organoid-based studies are expected to expand our knowledge from basic research to clinical applications for PCa diseases. Furthermore, we also highlight the optimization of PCa cultures and establishment of promising 3D organoid models for in vitro and in vivo investigations, ultimately facilitating mechanistic studies and development of novel clinical diagnosis/prognosis and therapies for PCa.

Phenotyping of Macrophages in Human Immune System Mice

Human immune system mice, also referred to as humanized mice, are a major research tool for the in vivo study of human immune system function. Upon reconstitution with human hematopoietic stem cells, all major human leukocyte populations develop in immunodeficient mice and can be detected in peripheral blood as well as in lymphatic and nonlymphatic tissue. This includes human macrophages that are intrinsically difficult to study from humans due to their organ-resident nature. In the following chapter, we provide a detailed protocol for generation of human immune system mice. We suggest that these mice are a suitable model to study human macrophage function in vivo.

Primary Human Leukemia Stem Cell (LSC) Isolation and Characterization

Leukemia stem cells (LSC) are thought to be the basis of leukemia progression since they are highly resistant to conventional chemotherapy. LSC isolation is critical in experimental studies, drug development, and application. Due to their likely hematopoietic stem cell (HSC) origin, LSCs have surface antigens that are similar to HSC. Surface markers such as CD34, CD123, CD133, and CD33 have been used extensively to assess LSCs. LSCs could be separated from other cells using magnetic selection (MS) or flow cytometry selection (FCS) methods using these markers. Understanding the role of LSCs in cancer progression and how to therapeutically target them in vitro and in vivo is critical for the development of LSC-targeting drug candidates. In this chapter, we set out to describe the primary human LSC purification and characterization processes used on patient samples with leukemia and lymphoma.

Advancements and application prospects of three-dimensional models for primary liver cancer: a comprehensive review

Primary liver cancer (PLC) is one of the most commonly diagnosed cancers worldwide and a leading cause of cancer-related deaths. However, traditional liver cancer models fail to replicate tumor heterogeneity and the tumor microenvironment, limiting the study and personalized treatment of liver cancer. To overcome these limitations, scientists have introduced three-dimensional (3D) culture models as an emerging research tool. These 3D models, utilizing biofabrication technologies such as 3D bioprinting and microfluidics, enable more accurate simulation of the in vivo tumor microenvironment, replicating cell morphology, tissue stiffness, and cell-cell interactions. Compared to traditional two-dimensional (2D) models, 3D culture models better mimic tumor heterogeneity, revealing differential sensitivity of tumor cell subpopulations to targeted therapies or immunotherapies. Additionally, these models can be used to assess the efficacy of potential treatments, providing guidance for personalized therapy. 3D liver cancer models hold significant value in tumor biology, understanding the mechanisms of disease progression, and drug screening. Researchers can gain deeper insights into the impact of the tumor microenvironment on tumor cells and their interactions with the surrounding milieu. Furthermore, these models allow for the evaluation of treatment responses, offering more accurate guidance for clinical interventions. In summary, 3D models provide a realistic and reliable tool for advancing PLC research. By simulating tumor heterogeneity and the microenvironment, these models contribute to a better understanding of the disease mechanisms and offer new strategies for personalized treatment. Therefore, 3D models hold promising prospects for future PLC research.

A novel FOXP3 knockout-humanized mouse model for pre-clinical safety and efficacy evaluation of Treg-like cell products

Forkhead box P3 (FOXP3) is an essential transcription factor for regulatory T cell (Treg) function. Defects in Tregs mediate many immune diseases including the monogenic autoimmune disease immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX), which is caused by FOXP3 mutations. Treg cell products are a promising modality to induce allograft tolerance or reduce the use of immunosuppressive drugs to prevent rejection, as well as in the treatment of acquired autoimmune diseases. We have recently opened a phase I clinical trial for IPEX patients using autologous engineered Treg-like cells, CD4LVFOXP3. To facilitate the pre-clinical studies, a novel humanized-mouse (hu-mouse) model was developed whereby immune-deficient mice were transplanted with human hematopoietic stem progenitor cells (HSPCs) in which the FOXP3 gene was knocked out (FOXP3KO) using CRISPR-Cas9. Mice transplanted with FOXP3KO HSPCs had impaired survival, developed lymphoproliferation 10-12 weeks post-transplant and T cell infiltration of the gut, resembling human IPEX. Strikingly, injection of CD4LVFOXP3 into the FOXP3KO hu-mice restored in vivo regulatory functions, including control of lymphoproliferation and inhibition of T cell infiltration in the colon. This hu-mouse disease model can be reproducibly established and constitutes an ideal model to assess pre-clinical efficacy of human Treg cell investigational products.

Therapeutic cancer vaccines: advancements, challenges, and prospects

With the development and regulatory approval of immune checkpoint inhibitors and adoptive cell therapies, cancer immunotherapy has undergone a profound transformation over the past decades. Recently, therapeutic cancer vaccines have shown promise by eliciting de novo T cell responses targeting tumor antigens, including tumor-associated antigens and tumor-specific antigens. The objective was to amplify and diversify the intrinsic repertoire of tumor-specific T cells. However, the complete realization of these capabilities remains an ongoing pursuit. Therefore, we provide an overview of the current landscape of cancer vaccines in this review. The range of antigen selection, antigen delivery systems development the strategic nuances underlying effective antigen presentation have pioneered cancer vaccine design. Furthermore, this review addresses the current status of clinical trials and discusses their strategies, focusing on tumor-specific immunogenicity and anti-tumor efficacy assessment. However, current clinical attempts toward developing cancer vaccines have not yielded breakthrough clinical outcomes due to significant challenges, including tumor immune microenvironment suppression, optimal candidate identification, immune response evaluation, and vaccine manufacturing acceleration. Therefore, the field is poised to overcome hurdles and improve patient outcomes in the future by acknowledging these clinical complexities and persistently striving to surmount inherent constraints.

Temporal evolution reveals bifurcated lineages in aggressive neuroendocrine small cell prostate cancer trans-differentiation

Trans-differentiation from an adenocarcinoma to a small cell neuroendocrine state is associated with therapy resistance in multiple cancer types. To gain insight into the underlying molecular events of the trans-differentiation, we perform a multi-omics time course analysis of a pan-small cell neuroendocrine cancer model (termed PARCB), a forward genetic transformation using human prostate basal cells and identify a shared developmental, arc-like, and entropy-high trajectory among all transformation model replicates. Further mapping with single cell resolution reveals two distinct lineages defined by mutually exclusive expression of ASCL1 or ASCL2. Temporal regulation by groups of transcription factors across developmental stages reveals that cellular reprogramming precedes the induction of neuronal programs. TFAP4 and ASCL1/2 feedback are identified as potential regulators of ASCL1 and ASCL2 expression. Our study provides temporal transcriptional patterns and uncovers pan-tissue parallels between prostate and lung cancers, as well as connections to normal neuroendocrine cell states.

Humanized mouse models for inherited thrombocytopenia studies

Inherited thrombocytopenia (IT) is a group of hereditary disorders characterized by a reduced platelet count as the main clinical manifestation, and often with abnormal platelet function, which can subsequently lead to impaired hemostasis. In the past decades, humanized mouse models (HMMs), that are mice engrafted with human cells or genes, have been widely used in different research areas including immunology, oncology, and virology. With advances of the development of immunodeficient mice, the engraftment, and reconstitution of functional human platelets in HMM permit studies of occurrence and development of platelet disorders including IT and treatment strategies. This article mainly reviews the development of humanized mice models, the construction methods, research status, and problems of using humanized mice for the in vivo study of human thrombopoiesis.

Progress in building clinically relevant patient-derived tumor xenograft models for cancer research

Patient-derived tumor xenograft (PDX) models, a method involving the surgical extraction of tumor tissues from cancer patients and subsequent transplantation into immunodeficient mice, have emerged as a pivotal approach in translational research, particularly in advancing precision medicine. As the first stage of PDX development, the patient-derived orthotopic xenograft (PDOX) models implant tumor tissue in mice in the corresponding anatomical locations of the patient. The PDOX models have several advantages, including high fidelity to the original tumor, heightened drug sensitivity, and an elevated rate of successful transplantation. However, the PDOX models present significant challenges, requiring advanced surgical techniques and resource-intensive imaging technologies, which limit its application. And then, the humanized mouse models, as well as the zebrafish models, were developed. Humanized mouse models contain a human immune environment resembling the tumor and immune system interplay. The humanized mouse models are a hot topic in PDX model research. Regarding zebrafish patient-derived tumor xenografts (zPDX) and patient-derived organoids (PDO) as promising models for studying cancer and drug discovery, zPDX models are used to transplant tumors into zebrafish as novel personalized medical animal models with the advantage of reducing patient waiting time. PDO models provide a cost-effective approach for drug testing that replicates the in vivo environment and preserves important tumor-related information for patients. The present review highlights the functional characteristics of each new phase of PDX and provides insights into the challenges and prospective developments in this rapidly evolving field.

Host Interactions with Engineered T-cell Micropharmacies

Genetically engineered, cytotoxic, adoptively transferred T cells localize to antigen-positive cancer cells inside patients, but tumor heterogeneity and multiple immune escape mechanisms have prevented the eradication of most solid tumor types. More effective, multifunctional engineered T cells are in development to overcome the barriers to the treatment of solid tumors, but the interactions of these highly modified cells with the host are poorly understood. We previously engineered prodrug-activating enzymatic functions into chimeric antigen receptor (CAR) T cells, endowing them with a killing mechanism orthogonal to conventional T-cell cytotoxicity. These drug-delivering cells, termed Synthetic Enzyme-Armed KillER (SEAKER) cells, demonstrated efficacy in mouse lymphoma xenograft models. However, the interactions of an immunocompromised xenograft with such complex engineered T cells are distinct from those in an immunocompetent host, precluding an understanding of how these physiologic processes may affect the therapy. Herein, we expanded the repertoire of SEAKER cells to target solid-tumor melanomas in syngeneic mouse models using specific targeting with T-cell receptor (TCR)-engineered T cells. We demonstrate that SEAKER cells localized specifically to tumors, and activated bioactive prodrugs, despite host immune responses. We additionally show that TCR-engineered SEAKER cells were efficacious in immunocompetent hosts, demonstrating that the SEAKER platform is applicable to many adoptive cell therapies.

Challenges and Prospects of Patient-Derived Xenografts for Cancer Research

We discuss the importance of the in vivo models in elucidating cancer biology, focusing on the patient-derived xenograft (PDX) models, which are classic and standard functional in vivo platforms for preclinical evaluation. We provide an overview of the most representative models, including cell-derived xenografts (CDX), tumor and metastatic cell-derived xenografts, and PDX models utilizing humanized mice (HM). The orthotopic models, which could reproduce the cancer environment and its progression, similar to human tumors, are particularly common. The standard procedures and rationales of gastric adenocarcinoma (GAC) orthotopic models are addressed. Despite the significant advantages of the PDX models, such as recapitulating key features of human tumors and enabling drug testing in the in vivo context, some challenges must be acknowledged, including loss of heterogeneity, selection bias, clonal evolution, stroma replacement, tumor micro-environment (TME) changes, host cell carryover and contaminations, human-to-host cell oncogenic transformation, human and host viral infections, as well as limitations for immunologic research. To compensate for these limitations, other mouse models, such as syngeneic and humanized mouse models, are currently utilized. Overall, the PDX models represent a powerful tool in cancer research, providing critical insights into tumor biology and potential therapeutic targets, but their limitations and challenges must be carefully considered for their effective use. Lastly, we present an intronic quantitative PCR (qPCR) method to authenticate, detect, and quantify human/murine cells in cell lines and PDX samples.

Targeting TCF19 sensitizes MSI endometrial cancer to anti-PD-1 therapy by alleviating CD8+ T cell exhaustion via TRIM14-IFN-β axis

Immune checkpoint blockade (ICB) therapies display clinical efficacy in microsatellite instable (MSI) endometrial cancer (EC) treatment, the key mechanism of which is reversing T cell exhaustion and restoration of anti-tumor immunity. Here, we demonstrate that transcription factor 19 (TCF19), one of the most significantly differentially expressed genes between MSI and microsatellite stable (MSS) patients in The Cancer Genome Atlas (TCGA)-EC cohort, is associated with poor prognosis and immune exhaustion signature. Specifically, TCF19 is significantly elevated in MSI EC, which in turn promotes tripartite motif-containing 14 (TRIM14) transcription and correlates with hyperactive signaling of the TANK-binding kinase 1 (TBK1)-interferon regulatory factor 3 (IRF3)-interferon β (IFN-β) pathway. The TCF19-TRIM14 axis promotes tumorigenicity under non-immunological background, and the enhanced downstream secretion of IFN-β facilitates CD8+ T cell exhaustion through cell differentiation reprogramming. Finally, using humanized models, we show that a combination of TCF19 inhibition and ICB therapy demonstrates more effective anti-tumor responses. Together, our study indicates that targeting TCF19 is a potent strategy for alleviating CD8+ T cell exhaustion and synergizing with ICB in tumor treatment.