Humanized mice in studying efficacy and mechanisms of PD-1-targeted cancer immunotherapy

Humanized mouse models of KRAS-mutated colorectal and pancreatic cancers with HLA-class-I match for pre-clinical evaluation of cancer immunotherapies

Cancer immunotherapy promises to treat challenging cancers including KRAS-mutated colorectal cancer (CRC) and pancreatic ductal adenocarcinoma (PDAC). However, pre-clinical animal models that better mimic patient tumor and immune system interactions are required. While humanized mice are promising vehicles for pre-clinical immunotherapy testing, currently used cancer models retain limitations, such as lack of a human thymus for human leukocyte antigen (HLA)-based education of human T cells. As cytotoxic T lymphocyte (CTL) activity underlies many immunotherapies, we developed more clinically relevant KRAS-mutated CRC and PDAC humanized cancer models using transgenic NRG-A2 mice expressing HLA-A2.1 to enable HLA-class-I match between mouse tissues (including the thymus), the humanized immune system and human tumors. Using these novel humanized cancer models and a CTL-mediated combination (immuno)therapy with clinical potential, we were able to recapitulate the complexity and therapy-induced changes reported in patient biopsies, demonstrating the use of these HLA-matched models for pre-clinical validation of novel immunotherapies.

Combined Molecular Subclass and Immune Phenotype Correlate to Atezolizumab Plus Radiation Therapy Response in Invasive Bladder Cancer: BPT-ART Phase 2 Study

PURPOSE

Bladder preservation therapy in combination with atezolizumab and radiation therapy trial, which was a multicenter, open-label, single-arm phase 2 study, showed a promisingly high interim clinical complete response (cCR) rate of 84.4% (38/45). In the present study, we aimed to identify potential tissue biomarkers for achieving cCR using bladder preservation therapy in combination with atezolizumab and radiation therapy.

METHODS AND MATERIALS

We used tumor tissue samples of the bladder and blood samples collected from patients at baseline to analyze the tumor immune microenvironment at baseline using an integrated approach of immunophenotyping, genomic, and tumor-infiltrating lymphocyte (TIL) profiling.

RESULTS

Immune phenotype analysis revealed that cCR rates of patients with the desert phenotype were as similarly high as patients with excluded/inflamed phenotypes (73.3% [11/15] vs 93.3% [14/15], P = .33) despite lower programmed death-ligand 1 expression levels in the desert phenotype. Genomic and TIL profiling then revealed that increased CD8+ and CD204+ TIL infiltration, high CD8:forkhead box protein P3 ratios in the stroma of the excluded/inflamed phenotypes, and gene alterations, such as CDK12, GNAS, NOTCH2, and AR1D1A, were associated with a high cCR rate (93.3%). Furthermore, the characteristics of these dual TILs, CD8-forkhead box protein P3 ratios, and gene alterations (especially FGFR3) bifurcated the desert phenotype into 2 subgroups with different cCR rates (100% [11/11] and 0% [0/4]).

CONCLUSIONS

These potential subgroups, defined by combined molecular subclass and immune phenotype, could lead to the identification of good responders to atezolizumab plus radiation therapy for invasive bladder cancer. However, given the small cohort size and limited number of tumor samples, these findings should be viewed as hypothesis-generating and require further validation in larger studies.

Engineering Mice to Study Human Immunity

Humanized mice, which carry a human hematopoietic and immune system, have greatly advanced our understanding of human immune responses and immunological diseases. These mice are created via the transplantation of human hematopoietic stem and progenitor cells into immunocompromised murine hosts further engineered to support human hematopoiesis and immune cell growth. This article explores genetic modifications in mice that enhance xeno-tolerance, promote human hematopoiesis and immunity, and enable xenotransplantation of human tissues with resident immune cells. We also discuss genetic editing of the human immune system, provide examples of how humanized mice with humanized organs model diseases for mechanistic studies, and highlight the roles of these models in advancing knowledge of organ biology, immune responses to pathogens, and preclinical drugs tested for cancer treatment. The integration of multi-omics and state-of-the art approaches with humanized mouse models is crucial for bridging existing human data with causality and promises to significantly advance mechanistic studies.

In vitro models: Can they unravel the complexities of cancer cell metastasis?

Metastasis still accounts for the majority of cancer-related deaths despite intense research efforts made worldwide to better understand the determinants involved and discover novel ways to halt it. However, studying the pathogenesis of metastasis in actual patients is indeed challenging which renders the need for the development of relevant experimental models urgent. Traditionally, several in vitro and in vivo models have been developed to study metastasis each of which having its own advantages and limitations. In the present review, we analyzed the current approaches used in cancer biology research to study cancer cell metastasis giving emphasis on the newly developed in vitro systems that take into account factors like the three-dimensional (3D) nature of the tumor, the interaction between cancer cells and the extracellular matrix or other cells present in the tumor microenvironment, and thus, better recapitulate the metastatic process. These approaches, namely 3D bioprinting, 3D tissue models, microfluidics systems, and spheroid generation are currently used separately or in combination depending on the research question and the cancer type in order to better represent the actual in vivo setting.

T Cell Development and Responses in Human Immune System Mice

Human Immune System (HIS) mice constructed with mature human immune cells or with human hematopoietic stem cells and thymic tissue have provided an important tool for human immunological research. In this article, we first review the different types of HIS mice based on human tissues transplanted and sources of the tissues. We then focus on knowledge of human T cell development and responses obtained using HIS mouse models. These areas include the development of human T cell subsets, with a focus on αβ conventional T cells and regulatory T cells, and human T cell responses in the settings of infection, transplantation rejection and tolerance, autoimmune disease, cancer immunotherapy, and regulatory T cell therapy. We also discuss the limitations and potential future applications of HIS mouse models.

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.

Establishment of CD34 + hematopoietic stem cell-derived xenograft model of hyperleukocytic acute myeloid leukemia

BACKGROUND

Hyperleukocytic acute myeloid leukemia (HLL) is marked by high early mortality and presents significant therapeutic challenges. Research on HLL is still in its infancy, and comprehensive development of patient-derived xenograft (PDX) models, especially CD34 + hematopoietic stem cell-derived models, remains limited.

METHODS

We evaluated the establishment of the HLL model through blood examinations, smear analysis, bone marrow biopsy, flow cytometry, and mutation analysis. Correlation between survival times in mice and patients was assessed using linear regression.

RESULTS

In the HLL PDX mouse model, leukocyte counts could reach up to 37.35^10⁹/L, and immunophenotyping revealed the presence of hCD45+, hCD15+, and hCD33 + cells in both peripheral blood (PB) and bone marrow (BM) following inoculation with PB-derived cells for the establishment of the HLL PDX model. Similar results were observed with cells derived from the patient's BM. In the CD34 + hematopoietic stem cell-derived xenograft model, extensive infiltration of CD34 + cells into the BM, liver, and spleen was observed. Additionally, human WT1 and NRAS mutations were identified in the liver, spleen, and BM of the mice. A comparative analysis of multiple experiments revealed that shorter survival times were observed in mice receiving a higher irradiation dose of 2.5 Gy and a greater number of cells derived from PB. Additionally, shorter survival times were observed in model mice injected with cells carrying NRAS, DNMT3A, FLT3, or NPM1 gene mutations. Correlation analysis indicated that the survival times of the mice were significantly associated with the survival status of the patients.

CONCLUSIONS

We successfully established a CD34 + hematopoietic stem cell-derived xenograft model of HLL, providing a valuable tool for mechanistic research, drug screening, individualized therapy, and precision medicine.

TRIAL REGISTRATION

Not application.

LSD1 inhibition corrects dysregulated MHC-I and dendritic cells activation through IFNγ-CXCL9-CXCR3 axis to promote antitumor immunity in HNSCC

Poor infiltration of CD8+ T cells and dysregulated MHC-I confer resistance to anticancer clinical therapies. This study aimed to elucidate the mechanisms of lysine-specific demethylase 1 (LSD1, encoded by KDM1A gene) in antitumor immunity in Head and Neck Squamous cell carcinoma (HNSCC). LSD1 inhibition in syngeneic and chronic tobacco carcinogen-induced HNSCC mice recruited activated dendritic cells (DCs), CD4+ and CD8+ T cells, enriched interferon-gamma (IFNγ) in T cells, CXCL9 in DCs, and CXCR3 in T cells, as evaluated using flow cytometry and single-cell RNA-seq analysis. Humanized HNSCC mice and TCGA data validated the inverse correlation of KDM1A with DC markers, CD8+ T cells, and their activating chemokines. Kdm1a knockout in mouse HNSCC and LSD1 inhibitor treatment to co-culture of human HNSCC cells with human peripheral blood mononuclear cells (PBMCs) resulted in MHC-I upregulation in cancer cells for efficient antigen presentation in tumors. Overall, LSD1 inhibition in tumor cells upregulates MHC class I and induces DCs to produce CXCL9, which in turn activates CD8+ T cells through the CXCL9-CXCR3 axis to produce IFNγ. Finally, we identified a novel mechanism by which LSD1 inhibition promotes the activation of H3K4me2 and its direct interaction with MHC-I to induce antitumor immunity. This may have implications in poorly immunogenic and immunotherapy-resistant cancers.

Statement of Significance

LSD1-mediated unique mechanisms have impact on epigenetic therapy, MHC-I resistant HNSCC therapies, and poor CD8+ and dendritic cell infilterated tumors.

Endothelial OX40 activation facilitates tumor cell escape from T cell surveillance through S1P/YAP-mediated angiogenesis

Understanding the complexity of the tumor microenvironment is vital for improving immunotherapy outcomes. Here, we report that the T cell costimulatory molecule OX40 was highly expressed in tumor endothelial cells (ECs) and was negatively associated with the prognosis of patients, which is irrelevant to T cell activation. Analysis of conditional OX40 loss- and gain-of-function transgenic mice showed that OX40 signal in ECs counteracted the antitumor effects produced in T cells by promoting angiogenesis. Mechanistically, leucine-rich repeat-containing GPCR5 (Lgr5+ ) cancer stem cells induced OX40 expression in tumor ECs via EGF/STAT3 signaling. Activated OX40 interacted with Spns lysolipid transporter 2 (Spns2), obstructing the export of sphingosine 1-phosphate (S1P) and resulting in S1P intracellular accumulation. Increased S1P directly bound to Yes 1-associated protein (YAP), disrupting its interaction with large tumor suppressor kinase 1 (LATS1) and promoting YAP nuclear translocation. Finally, the YAP inhibitor verteporfin enhanced the antitumor effects of the OX40 agonist. Together, these findings reveal an unexpected protumor role of OX40 in ECs, highlighting the effect of nonimmune cell compartments on immunotherapy.

Humanized Mouse Models for Immuno-Oncology Research: A Review and Implications in Lung Cancer Research

Cancer immunotherapy has brought significant clinical benefits to patients with cancer, including those with lung cancer. Patient-derived tumor xenograft mouse models have become the preferred animal model for translational cancer research and preclinical studies. Given the unmet need for improved predictive models in immuno-oncology, humanized mouse models which are co-engrafted with both human tumors and immune system components have been used to investigate novel immunotherapeutics. These models have similarly been used to predict immune-related adverse events and to develop predictive biomarkers. This review summarizes key concepts related to humanized mouse models. We highlight the various approaches to generate them, factors that are critical to successfully establishing such models, their respective limitations, and considerations in model selection for preclinical lung cancer immuno-oncology research and therapeutic studies.

Hematopoietic stem cells: Understanding the mechanisms to unleash the therapeutic potential of hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is a promising approach in regenerative medicine and serves as a standard treatment for different malignant and non-malignant conditions. Despite its widespread applications, HSCT is associated with various complications that compromise patients' lives and pose considerable risks of morbidity and mortality. Understanding the molecular physiology of HSCs is fundamental to ultimately enhance the mobilization, engraftment and differentiation of HSCs, thus unleashing the full therapeutic potential of HSCT in the treated patients. This review outlines the current understanding of HSC biology and its relevance to the clinical challenges associated with HSCT. Furthermore, we critically discuss the pros and cons of the preclinical murine models exploited in the HSCT field. Understanding the molecular physiology of HSCs will ultimately unleash the full therapeutic potential of HSCT. HSCs derived from induced pluripotent stem cells (iPSCs) might present an attractive tool which could be exploited preclinically and clinically. Nonetheless, further studies are warranted to systematically evaluate their potential in terms of improving the therapeutic outcome and minimizing the adverse effects of HSCT.

The cardio-oncologic burden of breast cancer: molecular mechanisms and importance of preclinical models

Breast cancer, the most prevalent cancer affecting women worldwide, poses a significant cardio-oncological burden. Despite advancements in novel therapeutic strategies, anthracyclines, HER2 antagonists, and radiation remain the cornerstones of oncological treatment. However, each carries a risk of cardiotoxicity, though the molecular mechanisms underlying these adverse effects differ. Common mechanisms include DNA damage response, increased reactive oxygen species, and mitochondrial dysfunction, which are key areas of ongoing research for potential cardioprotective strategies. Since these mechanisms are also essential for effective tumor cytotoxicity, we explore tumor-specific effects, particularly in hereditary breast cancer linked to BRCA1 and BRCA2 mutations. These genetic variants impair DNA repair mechanisms, increase the risk of tumorigenesis and possibly for cardiotoxicity from treatments such as anthracyclines and HER2 antagonists. Novel therapies, including immune checkpoint inhibitors, are used in the clinic for triple-negative breast cancer and improve the oncological outcomes of breast cancer patients. This review discusses the molecular mechanisms underlying BRCA dysfunction and the associated pathological pathways. It gives an overview of preclinical models of breast cancer, such as genetically engineered mouse models, syngeneic murine models, humanized mouse models, and various in vitro and ex vivo systems and models to study cardiovascular side effects of breast cancer therapies. Understanding the underlying mechanism of cardiotoxicity and developing cardioprotective strategies in preclinical models are essential for improving treatment outcomes and reducing long-term cardiovascular risks in breast cancer patients.

Mammary Cancer Models: An Overview from the Past to the Future

Breast cancer research heavily relies on diverse model systems to comprehend disease progression, develop novel diagnostics, and evaluate new therapeutic strategies. This review offers a comprehensive overview of mammary cancer models, covering both ex vivo and in vivo approaches. We delve into established techniques, such as cell culture and explore cutting-edge advancements, like tumor-on-a-chip and bioprinting. The in vivo section encompasses spontaneous, induced, and transplanted models, genetically engineered models, chick chorioallantoic membrane assays, and the burgeoning field of in silico models. Additionally, this article briefly highlights the key discoveries made using these models, significantly enhancing our understanding of breast cancer. In essence, this article serves as a comprehensive compass, charting the trajectory of mammary cancer modeling from its early beginnings to the promising vistas of tomorrow.

Microbubble-Protected Oncolytic Virotherapy Targeted by Sonoporation Induces Tumor Necrosis and T-Lymphocyte Infiltration in Humanized Mice Bearing Triple-Negative Breast Cancer

Oncolytic virotherapy has shown great promise in mediating targeted tumor destruction through tumor-selective replication and induction of anti-tumor immunity; however, obstacles remain for virus candidates to reach the clinic. These include avoiding neutralizing antibodies, preventing stimulation of the adaptive immune response during intravenous administration, and inducing sufficient apoptosis and immune activation so that the body's defense can work to eradicate systemic disease. We have developed a co-formulation of oncolytic viruses (OVs) with Imagent® lipid-encapsulated, perfluorocarbon microbubbles (MBs) to protect the OVs from the innate and adaptive immune system. Once inside the MB, the viral particles become acoustically active such that external ultrasound can target the delivery of the virus locally within the tumor. Humanized NSG female mice (Hu-CD34+ NSG-SGM3) engrafted in their flanks with MDA-MB-231-Luc triple-negative breast cancer (TNBC) cells were transduced with MB/OVs, with or without adjuvant Pembrolizumab treatment, and tumor sizes and tumor necrosis were assessed. The presence of CD8+ (cytotoxic T-cells), CD4+ (helper T-cells), and CD25+ (Tregs) tumor-infiltrating lymphocytes (TILs) was quantified in the tumor samples by immunohistochemistry. In an in vivo model of humanized mice engrafted with a human immune system, we observed significantly greater tumor necrosis and smaller tumor mass in human TNBC xenografts systemically treated with MB/OV complexes in the presence or absence of pembrolizumab adjuvant treatment, compared to controls. Additionally, we observed a low ratio of CD4+/CD8+ TILs and a high ratio of CD8+/CD25+ TILs in the MDA-MB-231 xenografts treated with MB/OVs complexes with or without pembrolizumab adjuvant treatment, compared to controls. Our study demonstrated the feasibility of using MBs to target OVs to TNBC through diagnostic ultrasound, which decreased tumor mass by increasing tumor necrosis and stimulated a local and systemic antitumoral immune response by increasing intratumoral CD8+ T-cytotoxic lymphocyte infiltration and decreasing CD25+ Treg cells.

Microdissected tumor cuboids: a microscale cancer model for large-scale testing that retains a complex tumor microenvironment

To bridge the gap between bench and bedside, there is a need for more faithful models of human cancers that can recapitulate key features of the human tumor microenvironment (TME) and simultaneously facilitate large-scale drug tests. Our recently developed microdissection method optimizes the yield of large numbers of cuboidal microtissues (″cuboids″, ~(400 µm) 3 ) from a tumor biopsy. Here we demonstrate that cuboids from syngeneic mouse tumor models and human tumors retain a complex TME, making them amenable for drug and immunotherapy evaluation. We characterize relevant TME parameters, such as cellular architecture, cytokine secretion, proteomics profiles, and response to drug panels in multi-well arrays. Despite the cutting procedure and the time spent in culture (up to 7 days), the cuboids display strong cytokine expression and drug responses, including to immunotherapy. Overall, our results suggest that cuboids could provide essential therapeutic information for personalized oncology applications and could help the development of TME-dependent therapeutics and cancer disease models, including for clinical trials.

Humanized patient-derived xenograft mouse model bearing ovarian clear cell carcinoma

OBJECTIVE

The study aimed to establish humanized patient-derived xenograft (PDX) mouse models of ovarian clear cell carcinoma (OCCC) and evaluate their therapeutic responses.

METHODS

PDX models and their humanized counterparts (CD34+ humanized PDX models) derived from the same tumor source were developed, and the therapeutic responses were compared between the models.

RESULTS

Treatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor significantly reduced tumor size in traditional OCCC PDX models (p=0.021). Although differences in tumor growth between traditional PDX models and humanized PDX models were observed, they were not statistically significant (p=0.438). However, treatment effects of PI3K inhibitor differed significantly between conventional and humanized mice (p=0.006). In the Humanized PDX cohort, both programmed cell death protein-1 antibody monotherapy and PI3K inhibitor treatment slowed tumor growth relative to controls, with a synergistic effect noted during the latter part of the study, though these effects were not statistically significant.

CONCLUSION

This pioneering study successfully develop a humanized PDX model for OCCC, highlighting differential responses to treatments compared to conventional PDX models.

Prodrugs of paclitaxel improve in situ photo-vaccination

Photodynamic therapy (PDT) effectively kills cancer cells and initiates immune responses that promote anticancer effects locally and systemically. Primarily developed for local and regional cancers, the potential of PDT for systemic antitumor effects [in situ photo-vaccination (ISPV)] remains underexplored. This study investigates: (1) the comparative effectiveness of paclitaxel (PTX) prodrug [Pc-(L-PTX)2] for PDT and site-specific PTX effects versus its pseudo-prodrug [Pc-(NCL-PTX)2] for PDT combined with checkpoint inhibitors; (2) mechanisms driving systemic antitumor effects; and (3) the prophylactic impact on preventing cancer recurrence. A bilateral tumor model was established in BALB/c mice through subcutaneous injection of CT26 cells. Mice received the PTX prodrug (0.5 μmole kg-1, i.v.), and tumors were treated with a 690-nm laser (75 mW cm-2 for 30 min, drug-light interval 0.5 h, light does 135 J cm-1), followed by anti-CTLA-4 (100 μg dose-1, i.p.) on days 1, 4, and 7. Notable enhancement in both local and systemic antitumor effectiveness was observed with [Pc-(L-PTX)2] compared to [Pc-(NCL-PTX)2] with checkpoint inhibitor. Immune cell depletion and immunohistochemistry confirmed neutrophils and CD8+ T cells are effectors for systemic antitumor effects. Treatment-induced immune memory resisted newly rechallenged CT26, showcasing prophylactic benefits. ISPV with a PTX prodrug and anti-CTLA-4 is a promising approach for treating metastatic cancers and preventing recurrence.

CircRNome-wide characterisation reveals the promoting role of circAATF in anti-PD-L1 immunotherapy of gallbladder carcinoma

Circular RNAs (circRNAs) have been shown to play important roles in tumour development and tumour immunology. However, genome-wide characterisation of circRNAs and their roles in the immunology and immunotherapy of gallbladder carcinoma (GBC) has been lacking. We present a comprehensive characterisation of the circRNA landscape in GBC, revealing GBC-specific circRNAs. Our analysis found that circRNAs are significantly enriched in cell proliferation and are involved in cancer-related hallmarks. In particular, circAATF was upregulated in GBC, which was positively correlated with AATF mRNA expression, and promoted GBC cell growth. Through integrating computational and experimental approaches, we revealed that circAATF is positively associated with the CD4+ T cell abundance and PD-L1 level, and enhances the clinical benefits of anti-PD-L1 immunotherapy for GBC. We further demonstrate that circAATF elevates the PD-L1 level by activating phosphorylated AKT and acting as a sponge for miR-142-5p. CircAATF is positively associated with CD4+ T cells and PD-L1 levels and shows potential to aid anti-PD-L1 immunotherapy for GBC. Our study provides insights into roles of circAATF in the tumour development and immunology of GBC and accelerates the development of therapeutic strategies for GBC immunotherapy. HIGHLIGHTS: We present a comprehensive characterisation of circRNA landscape in gallbladder carcinoma (GBC). CircAATF is positively associated with CD4+ T cell abundance and PD-L1 expression and is shown to promote PD-L1 treatment in mouse model. CircAATF can elevate PD-L1 level through phosphorylated AKT and linear AATF, which upregulates PD-L1 by acting as a sponge of miR-142-5p.

Computational immune synapse analysis reveals T-cell interactions in distinct tumor microenvironments

The tumor microenvironment (TME) and the cellular interactions within it can be critical to tumor progression and treatment response. Although technologies to generate multiplex images of the TME are advancing, the many ways in which TME imaging data can be mined to elucidate cellular interactions are only beginning to be realized. Here, we present a novel approach for multipronged computational immune synapse analysis (CISA) that reveals T-cell synaptic interactions from multiplex images. CISA enables automated discovery and quantification of immune synapse interactions based on the localization of proteins on cell membranes. We first demonstrate the ability of CISA to detect T-cell:APC (antigen presenting cell) synaptic interactions in two independent human melanoma imaging mass cytometry (IMC) tissue microarray datasets. We then verify CISA's applicability across data modalities with melanoma histocytometry whole slide images, revealing that T-cell:macrophage synapse formation correlates with T-cell proliferation. We next show the generality of CISA by extending it to breast cancer IMC images, finding that CISA quantifications of T-cell:B-cell synapses are predictive of improved patient survival. Our work demonstrates the biological and clinical significance of spatially resolving cell-cell synaptic interactions in the TME and provides a robust method to do so across imaging modalities and cancer types.

Label-free, real-time monitoring of cytochrome C drug responses in microdissected tumor biopsies with a multi-well aptasensor platform

Functional assays on intact tumor biopsies can complement genomics-based approaches for precision oncology, drug testing, and organs-on-chips cancer disease models by capturing key therapeutic response determinants, such as tissue architecture, tumor heterogeneity, and the tumor microenvironment. Most of these assays rely on fluorescent labeling, a semiquantitative method best suited for single-time-point assays or labor-intensive immunostaining analysis. Here, we report integrated aptamer electrochemical sensors for on-chip, real-time monitoring of cytochrome C, a cell death indicator, from intact microdissected tissues with high affinity and specificity. The platform features a multi-well sensor layout and a multiplexed electronic setup. The aptasensors measure increases in cytochrome C in the supernatant of mouse or human microdissected tumors after exposure to various drug treatments. Because of the sensor's high affinity, it primarily tracks rising concentrations of cytochrome C, capturing dynamic changes during apoptosis. This approach could help develop more advanced cancer disease models and apply to other complex in vitro disease models, such as organs-on-chips and organoids.

Dynamic changes in immune cells in humanized liver metastasis and subcutaneous xenograft mouse models

Preclinical drug efficacy and tumor microenvironment (TME) investigations often utilize humanized xenograft mouse models, yet these models typically fall short in replicating the intricate TME. We developed a humanized liver metastasis (LM) model by transplanting human peripheral blood mononuclear cells (PBMCs) and assessed it against the conventional subcutaneous (SC) xenograft model, focusing on immune cell dynamics post-transplantation and immunotherapy response. NOD-scid IL2Rgammanull(NSG) were inoculated with PBMCs to create humanized models. We induced SC and LM models using HCT116 cells, to investigate and compare the distributions and transformations of immune cell subsets, respectively. Both models were subjected to anti-PD-L1 therapy, followed by an analysis the TME analysis. The LM model demonstrated enhanced central tumor infiltration by tumor-infiltrating lymphocytes (TILs) compared to the peripheral pattern of SC model. TIL subpopulations in the LM model showed a progressive increase, contrasting with an initial rise and subsequent decline in the SC model. Post-anti-PD-L1 therapy, the LM model exhibited a significant rise in central and effector memory T cells, a response absents in the SC model. Our study highlights differential TME responses between SC and LM models and introduces a robust humanized LM model that swiftly indicates the potential efficacy of immunotherapies. These insights could streamline the preclinical evaluation of TME-targeting immunotherapeutic agents.

A novel anti-FGFR1 monoclonal antibody OM-RCA-01 exhibits potent antitumor activity and enhances the efficacy of immune checkpoint inhibitors in lung cancer models

Background

Fibroblast growth factor receptor 1 (FGFR1) plays a crucial role in carcinogenesis. Exploring the combination of the novel humanized monoclonal anti-FGFR1 antibody OM-RCA-01 and immunotherapy was intriguing due to involvement of FGFR1 in mechanisms of resistance to checkpoint inhibitors.

Materials and methods

Lung cancer A549, exhibiting distinct levels of FGFR1 expression, were cultured in basic FGF medium with OM-RCA-01 supplementation. The efficacy of antibody monotherapy was validated in a lung cancer xenograft study. To investigate whether OM-RCA-01 could enhance the efficacy of immunotherapy in vitro and in vivo, mixed lymphocyte reaction/Staphylococcal enterotoxin B assays and FGFR1/programmed death-ligand 1-positive patient-derived xenograft model were established.

Results

The antibody effectively suppressed receptor phosphorylation, resulting in inhibited cell proliferation. OM-RCA-01 led to a substantial delay in tumor growth compared to non-specific immunoglobulin G in a xenograft study. The median tumor volume was 1048.5 mm3 and 2174 mm3 in the study and vehicle groups, respectively, representing a twofold difference in favor of the anti-FGFR1 antibody. In vitro, the combination of nivolumab and OM-RCA-01 resulted in higher levels of interferon gamma and interleukin-2 release compared with nivolumab alone. In vivo, pembrolizumab in combination with OM-RCA-01 produced a greater inhibitory effect on tumor growth compared with vehicle and pembrolizumab alone. The curve plateaued, indicating minimal tumor growth from day 16 onwards in the combination group. The OM-RCA-01 demonstrated no toxicity, even at therapeutic doses or higher doses.

Conclusions

Our preclinical studies demonstrate that OM-RCA-01 exhibits robust activity with minimal toxicity. Combining an anti-FGFR1 antibody with a checkpoint inhibitor may enhance the efficacy of both drugs. However, further studies are needed to elucidate the mechanism of this interaction.

Translational modeling-based evidence for enhanced efficacy of standard-of-care drugs in combination with anti-microRNA-155 in non-small-cell lung cancer

BACKGROUND

Elevated microRNA-155 (miR-155) expression in non-small-cell lung cancer (NSCLC) promotes cisplatin resistance and negatively impacts treatment outcomes. However, miR-155 can also boost anti-tumor immunity by suppressing PD-L1 expression. Therapeutic targeting of miR-155 through its antagonist, anti-miR-155, has proven challenging due to its dual molecular effects.

METHODS

We developed a multiscale mechanistic model, calibrated with in vivo data and then extrapolated to humans, to investigate the therapeutic effects of nanoparticle-delivered anti-miR-155 in NSCLC, alone or in combination with standard-of-care drugs.

RESULTS

Model simulations and analyses of the clinical scenario revealed that monotherapy with anti-miR-155 at a dose of 2.5 mg/kg administered once every three weeks has substantial anti-cancer activity. It led to a median progression-free survival (PFS) of 6.7 months, which compared favorably to cisplatin and immune checkpoint inhibitors. Further, we explored the combinations of anti-miR-155 with standard-of-care drugs, and found strongly synergistic two- and three-drug combinations. A three-drug combination of anti-miR-155, cisplatin, and pembrolizumab resulted in a median PFS of 13.1 months, while a two-drug combination of anti-miR-155 and cisplatin resulted in a median PFS of 11.3 months, which emerged as a more practical option due to its simple design and cost-effectiveness. Our analyses also provided valuable insights into unfavorable dose ratios for drug combinations, highlighting the need for optimizing dose regimens to prevent antagonistic effects.

CONCLUSIONS

This work bridges the gap between preclinical development and clinical translation of anti-miR-155 and unravels the potential of anti-miR-155 combination therapies in NSCLC.

Immune checkpoint inhibitor monotherapy is sufficient to promote microenvironmental normalization via the type I interferon pathway in PD-L1-expressing head and neck cancer

Immune checkpoint blockers (ICBs) targeting programmed cell death protein 1 (PD-1) have been proven to be an effective first-line therapy against programmed cell death 1 ligand 1 (PD-L1; also known as CD274 molecule)-expressing head and neck squamous cell carcinoma (HNSCC) in recent KEYNOTE-048 trial. However, associated changes in the tumor microenvironment (TME) and underlying mechanisms remain elusive. Oral tumors in C57/BL6 mice were induced by administering 7,12-dimethylbenzanthracene into the buccal mucosa. Single-cell suspension was isolated from tumor tissue; proliferating cells were injected subcutaneously into the left flank of mice to establish Ajou oral cancer (AOC) cell lines. Subsequently, a syngeneic PD-L1-expressing HNSCC model was developed by injecting AOC cells into the buccal or tongue area. The model recapitulated human HNSCC molecular features and showed reliable in vivo tumorigenicity with significant PD-L1 expression. ICB monotherapy induced global changes in the TME, including vascular normalization. Furthermore, the antitumor effect of ICB monotherapy was superior to those of other therapeutic agents, including cisplatin and inhibitors of vascular endothelial growth factor receptor 2 (VEGFR2). The ICB-induced antitumorigenicity and TME normalization were alleviated by blocking the type I interferon pathway. In summary, ICB monotherapy is sufficient to induce TME normalization in the syngeneic model; the type I interferon pathway is indispensable in realizing the effects of ICBs. Furthermore, these results explain the underlying mechanism of the efficacy of ICB monotherapy against PD-L1-expressing HNSCC in the KEYNOTE-048 trial.

Recent advancements of hydrogels in immunotherapy: Breast cancer treatment

Breast cancer is the most prevalent cancer among women and the leading cause of cancer-related deaths in this population. Recent advances in Immunotherapy, or combined immunotherapy, offering a more targeted and less toxic approach, expand the survival rate of patients more than conventional treatment. Notably, hydrogels, a versatile platform provided promising avenues to combat breast cancer in preclinical studies and extended to clinical practices. With advantages such as the alternation of tumor microenvironment, immunomodulation, targeted delivery of therapeutic agents, and their sustained release at specific sites of interest, hydrogels can potentially be used for the treatment of breast cancer. This review highlights the advantages, mechanisms of action, stimuli-responsiveness properties, and recent advancements of hydrogels for treating breast cancer immunotherapy. Moreover, post-treatment and its clinical translations are discussed in this review. The integration of hydrogels in immunotherapy strategies may pave the way for more effective, personalized, and patient-friendly approaches to combat breast cancer, ultimately contributing to a brighter future for breast cancer patients.

Development of a Multiscale Mechanistic Model for Predicting Tumor Response to Anti-miR-155

In this paper, we present a two-compartmental multiscale mechanistic model for investigating anti-miR-155 monotherapy for non-small cell lung cancer (NSCLC). The model was first quantified using in vivo data and subsequently extrapolated to human-scale for evaluating its translational potential in patients. Using the human-scale model, we explored the impact of dosing schedules on tumor response. The model demonstrated the efficacy of anti-miR-155 monotherapy in a virtual NSCLC patient, revealing treatment schedule-dependent suppression of tumor growth. Further analysis of the model will include testing the synergistic effects of anti-miR-155 with standard-of-care drugs, which will help design and optimize treatment schedules for combination therapy in NSCLC.

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.

Fetal liver CD34+ contain human immune and endothelial progenitors and mediate solid tumor rejection in NOG mice

BACKGROUND

Transplantation of CD34+ hematopoietic stem and progenitor cells (HSPC) into immunodeficient mice is an established method to generate humanized mice harbouring a human immune system. Different sources and methods for CD34+ isolation have been employed by various research groups, resulting in customized models that are difficult to compare. A more detailed characterization of CD34+ isolates is needed for a better understanding of engraftable hematopoietic and potentially non-hematopoietic cells. Here we have performed a direct comparison of CD34+ isolated from cord blood (CB-CD34+) or fetal liver (FL-CD34+ and FL-CD34+CD14-) and their engraftment into immunocompromised NOD/Shi-scid Il2rgnull (NOG) mice.

METHODS

NOG mice were transplanted with either CB-CD34+, FL-CD34+ or FL-CD34+CD14- to generate CB-NOG, FL-NOG and FL-CD14--NOG, respectively. After 15-20 weeks, the mice were sacrificed and human immune cell reconstitution was assessed in blood and several organs. Liver sections were pathologically assessed upon Haematoxylin and Eosin staining. To assess the capability of allogenic tumor rejection in CB- vs. FL-reconstituted mice, animals were subcutaneously engrafted with an HLA-mismatched melanoma cell line. Tumor growth was assessed by calliper measurements and a Luminex-based assay was used to compare the cytokine/chemokine profiles.

RESULTS

We show that CB-CD34+ are a uniform population of HSPC that reconstitute NOG mice more rapidly than FL-CD34+ due to faster B cell development. However, upon long-term engraftment, FL-NOG display increased numbers of neutrophils, dendritic cells and macrophages in multiple tissues. In addition to HSPC, FL-CD34+ isolates contain non-hematopoietic CD14+ endothelial cells that enhance the engraftment of the human immune system in FL-NOG mice. We demonstrate that these CD14+CD34+ cells are capable of reconstituting Factor VIII-producing liver sinusoidal endothelial cells (LSEC) in FL-NOG. However, CD14+CD34+ also contribute to hepatic sinusoidal dilatation and immune cell infiltration, which may culminate in a graft-versus-host disease (GVHD) pathology upon long-term engraftment. Finally, using an HLA-A mismatched CDX melanoma model, we show that FL-NOG, but not CB-NOG, can mount a graft-versus-tumor (GVT) response resulting in tumor rejection.

CONCLUSION

Our results highlight important phenotypical and functional differences between CB- and FL-NOG and reveal FL-NOG as a potential model to study hepatic sinusoidal dilatation and mechanisms of GVT.

Mouse Models for Head and Neck Squamous Cell Carcinoma

The prognosis and survival rate of head and neck squamous cell carcinoma (HNSCC) have remained unchanged for years, and the pathogenesis of HNSCC is still not fully understood, necessitating further research. An ideal animal model that accurately replicates the complex microenvironment of HNSCC is urgently needed. Among all the animal models for preclinical cancer research, tumor-bearing mouse models are the best known and widely used due to their high similarity to humans. Currently, mouse models for HNSCC can be broadly categorized into chemical-induced models, genetically engineered mouse models (GEMMs), and transplanted mouse models, each with its distinct advantages and limitations. In chemical-induced models, the carcinogen spontaneously initiates tumor formation through a multistep process. The resemblance of this model to human carcinogenesis renders it an ideal preclinical platform for studying HNSCC initiation and progression from precancerous lesions. The major drawback is that these models are time-consuming and, like human cancer, unpredictable in terms of timing, location, and number of lesions. GEMMs involve transgenic and knockout mice with gene modifications, leading to malignant transformation within a tumor microenvironment that recapitulates tumorigenesis in vivo, including their interaction with the immune system. However, most HNSCC GEMMs exhibit low tumor incidence and limited prognostic significance when translated to clinical studies. Transplanted mouse models are the most widely used in cancer research due to their consistency, availability, and efficiency. Based on the donor and recipient species matching, transplanted mouse models can be divided into xenografts and syngeneic models. In the latter, transplanted cells and host are from the same strain, making syngeneic models relevant to study functional immune system. In this review, we provide a comprehensive summary of the characteristics, establishment methods, and potential applications of these different HNSCC mouse models, aiming to assist researchers in choosing suitable animal models for their research.

New insights into immune cells in cancer immunotherapy: from epigenetic modification, metabolic modulation to cell communication

Cancer is one of the leading causes of death worldwide, and more effective ways of attacking cancer are being sought. Cancer immunotherapy is a new and effective therapeutic method after surgery, radiotherapy, chemotherapy, and targeted therapy. Cancer immunotherapy aims to kill tumor cells by stimulating or rebuilding the body's immune system, with specific efficiency and high safety. However, only few tumor patients respond to immunotherapy and due to the complex and variable characters of cancer immune escape, the behavior and regulatory mechanisms of immune cells need to be deeply explored from more dimensions. Epigenetic modifications, metabolic modulation, and cell-to-cell communication are key factors in immune cell adaptation and response to the complex tumor microenvironment. They collectively determine the state and function of immune cells through modulating gene expression, changing in energy and nutrient demands. In addition, immune cells engage in complex communication networks with other immune components, which are mediated by exosomes, cytokines, and chemokines, and are pivotal in shaping the tumor progression and therapeutic response. Understanding the interactions and combined effects of such multidimensions mechanisms in immune cell modulation is important for revealing the mechanisms of immunotherapy failure and developing new therapeutic targets and strategies.

Transcriptome profiling and characterization of peritoneal metastasis ovarian cancer xenografts in humanized mice

Although immunotherapy has not yet been as successful in ovarian cancer (OC), it remains a potential therapeutic strategy. Preclinical models of OC are necessary to evaluate the efficacy of immuno-oncology (IO) drugs targeting human immune components but have been underutilized. Developing mouse models with a humanized (Hu) immune system can help understand the human immune response to IO drugs which have demonstrated limited effectiveness in OC patients. We established OC xenograft Hu-mouse models by intraperitoneally injecting luciferase-expressing SKOV-3 Luc and OVCAR-3 Luc OC cells into CD34+ Hu-mice. Tumor growth was monitored through bioluminescence imaging (BLI). In the SKOV-3 Luc Hu-mouse model, we assessed the efficacy of PD-1 blockade with pembrolizumab. We observed the presence of human lymphocyte and myeloid cell subsets within the tumors, lymph nodes, blood, and spleens in these models. Notably, these tumors exhibited a high prevalence of tumor-infiltrating macrophages. Furthermore, we identified HDAC class I target genes, and genes associated with epithelial-mesenchymal transition (EMT) and fibroblasts in the tumors of Hu-mice treated with pembrolizumab. Our xenograft Hu-mouse model of OC provides a valuable tool for investigating the efficacy of IO drugs. The insights gained from this model offer useful information to explore potential mechanisms associated with unresponsive anti-PD-1 treatment in OC.

Neoadjuvant radiotherapy in ER+, HER2+, and triple-negative -specific breast cancer based humanized tumor mice enhances anti-PD-L1 treatment efficacy

Pre-operative radiation therapy is not currently integrated into the treatment protocols for breast cancer. However, transforming immunological "cold" breast cancers by neoadjuvant irradiation into their "hot" variants is supposed to elicit an endogenous tumor immune defense and, thus, enhance immunotherapy efficiency. We investigated cellular and immunological effects of sub-lethal, neoadjuvant irradiation of ER pos., HER2 pos., and triple-negative breast cancer subtypes in-vitro and in-vivo in humanized tumor mice (HTM). This mouse model is characterized by a human-like immune system and therefore facilitates detailed analysis of the mechanisms and efficiency of neoadjuvant, irradiation-induced "in-situ vaccination", especially in the context of concurrently applied checkpoint therapy. Similar to clinical appearances, we observed a gradually increased immunogenicity from the luminal over the HER2-pos. to the triple negative subtype in HTM indicated by an increasing immune cell infiltration into the tumor tissue. Anti-PD-L1 therapy divided the HER2-pos. and triple negative HTM groups into responder and non-responder, while the luminal HTMs were basically irresponsive. Irradiation alone was effective in the HER2-pos. and luminal subtype-specific HTM and was supportive for overcoming irresponsiveness to single anti-PD-L1 treatment. The treatment success correlated with a significantly increased T cell proportion and PD-1 expression in the spleen. In all subtype-specific HTM combination therapy proved most effective in diminishing tumor growth, enhancing the immune response, and converted non-responder into responder during anti-PD-L1 therapy. In HTM, neoadjuvant irradiation reinforced anti-PD-L1 checkpoint treatment of breast cancer in a subtype -specific manner. According to the "bench to bedside" principle, this study offers a vital foundation for clinical translating the use of neoadjuvant irradiation in the context of checkpoint therapy.

Autologous human preclinical modeling of melanoma interpatient clinical responses to immunotherapeutics

BACKGROUND

Despite recent advances in immunotherapy, a substantial population of late-stage melanoma patients still fail to achieve sustained clinical benefit. Lack of translational preclinical models continues to be a major challenge in the field of immunotherapy; thus, more optimized translational models could strongly influence clinical trial development. To address this unmet need, we designed a preclinical model reflecting the heterogeneity in melanoma patients' clinical responses that can be used to evaluate novel immunotherapies and synergistic combinatorial treatment strategies. Using our all-autologous humanized melanoma mouse model, we examined the efficacy of a novel engineered interleukin 2 (IL-2)-based cytokine variant immunotherapy.

METHODS

To study immune responses and antitumor efficacy for human melanoma tumors, we developed an all-autologous humanized melanoma mouse model using clinically annotated, matched patient tumor cells and peripheral blood mononuclear cells (PBMCs). After inoculating immunodeficient NSG mice with patient tumors and an adoptive cell transfer of autologous PBMCs, mice were treated with anti-PD-1, a novel investigational engineered IL-2-based cytokine (nemvaleukin), or recombinant human IL-2 (rhIL-2). The pharmacodynamic effects and antitumor efficacy of these treatments were then evaluated. We used tumor cells and autologous PBMCs from patients with varying immunotherapy responses to both model the diversity of immunotherapy efficacy observed in the clinical setting and to recapitulate the heterogeneous nature of melanoma.

RESULTS

Our model exhibited long-term survival of engrafted human PBMCs without developing graft-versus-host disease. Administration of an anti-PD-1 or nemvaleukin elicited antitumor responses in our model that were patient-specific and were found to parallel clinical responsiveness to checkpoint inhibitors. An evaluation of nemvaleukin-treated mice demonstrated increased tumor-infiltrating CD4+ and CD8+ T cells, preferential expansion of non-regulatory T cell subsets in the spleen, and significant delays in tumor growth compared with vehicle-treated controls or mice treated with rhIL-2.

CONCLUSIONS

Our model reproduces differential effects of immunotherapy in melanoma patients, capturing the inherent heterogeneity in clinical responses. Taken together, these data demonstrate our model's translatability for novel immunotherapies in melanoma patients. The data are also supportive for the continued clinical investigation of nemvaleukin as a novel immunotherapeutic for the treatment of melanoma.

TheraVision: Engineering platform technology for the development of oncolytic viruses based on herpes simplex virus type 1

Viruses are able to efficiently penetrate cells, multiply, and eventually kill infected cells, release tumor antigens, and activate the immune system. Therefore, viruses are highly attractive novel agents for cancer therapy. Clinical trials with first generations of oncolytic viruses (OVs) are very promising but show significant need for optimization. The aim of TheraVision was to establish a broadly applicable engineering platform technology for combinatorial oncolytic virus and immunotherapy. Through genetic engineering, an attenuated herpes simplex virus type 1 (HSV1) was generated that showed increased safety compared to the wild-type strain. To demonstrate the modularity and the facilitated generation of new OVs, two transgenes encoding retargeting as well as immunomodulating single-chain variable fragments (scFvs) were integrated into the platform vector. The resulting virus selectively infected epidermal growth factor receptor (EGFR)-expressing cells and produced a functional immune checkpoint inhibitor against programmed cell death protein 1 (PD-1). Thus, both viral-mediated oncolysis and immune-cell-mediated therapy were combined into a single viral vector. Safety and functionality of the armed OVs have been shown in novel preclinical models ranging from patient-derived organoids and tissue-engineered human in vitro 3D tumor models to complex humanized mouse models. Consequently, a novel and proprietary engineering platform vector based on HSV1 is available for the facilitated preclinical development of oncolytic virotherapy.

Translational modeling-based evidence for enhanced efficacy of standard-of-care drugs in combination with anti-microRNA-155 in non-small-cell lung cancer

Elevated microRNA-155 (miR-155) expression in non-small-cell lung cancer (NSCLC) promotes cisplatin resistance and negatively impacts treatment outcomes. However, miR-155 can also boost anti-tumor immunity by suppressing PD-L1 expression. We developed a multiscale mechanistic model, calibrated with in vivo data and then extrapolated to humans, to investigate the therapeutic effects of nanoparticle-delivered anti-miR-155 in NSCLC, alone or in combination with standard-of-care drugs. Model simulations and analyses of the clinical scenario revealed that monotherapy with anti-miR-155 at a dose of 2.5 mg/kg administered once every three weeks has substantial anti-cancer activity. It led to a median progression-free survival (PFS) of 6.7 months, which compared favorably to cisplatin and immune checkpoint inhibitors. Further, we explored the combinations of anti-miR-155 with standard-of-care drugs, and found strongly synergistic two- and three-drug combinations. A three-drug combination of anti-miR-155, cisplatin, and pembrolizumab resulted in a median PFS of 13.1 months, while a two-drug combination of anti-miR-155 and cisplatin resulted in a median PFS of 11.3 months, which emerged as a more practical option due to its simple design and cost-effectiveness. Our analyses also provided valuable insights into unfavorable dose ratios for drug combinations, highlighting the need for optimizing dose regimen to prevent antagonistic effects. Thus, this work bridges the gap between preclinical development and clinical translation of anti-miR-155 and unravels the potential of anti-miR-155 combination therapies in NSCLC.

Immune-restoring CAR-T cells display antitumor activity and reverse immunosuppressive TME in a humanized ccRCC mouse model

One of the major barriers that have restricted successful use of chimeric antigen receptor (CAR) T cells in the treatment of solid tumors is an unfavorable tumor microenvironment (TME). We engineered CAR-T cells targeting carbonic anhydrase IX (CAIX) to secrete anti-PD-L1 monoclonal antibody (mAb), termed immune-restoring (IR) CAR G36-PDL1. We tested CAR-T cells in a humanized clear cell renal cell carcinoma (ccRCC) orthotopic mouse model with reconstituted human leukocyte antigen (HLA) partially matched human leukocytes derived from fetal CD34+ hematopoietic stem cells (HSCs) and bearing human ccRCC skrc-59 cells under the kidney capsule. G36-PDL1 CAR-T cells, haploidentical to the tumor cells, had a potent antitumor effect compared to those without immune-restoring effect. Analysis of the TME revealed that G36-PDL1 CAR-T cells restored active antitumor immunity by promoting tumor-killing cytotoxicity, reducing immunosuppressive cell components such as M2 macrophages and exhausted CD8+ T cells, and enhancing T follicular helper (Tfh)-B cell crosstalk.

Label-Free, Real-Time Monitoring of Cytochrome C Responses to Drugs in Microdissected Tumor Biopsies with a Multi-Well Aptasensor Platform

Functional assays on intact tumor biopsies can potentially complement and extend genomics-based approaches for precision oncology, drug testing, and organs-on-chips cancer disease models by capturing key determinants of therapeutic response, such as tissue architecture, tumor heterogeneity, and the tumor microenvironment. Currently, most of these assays rely on fluorescent labeling, a semi-quantitative method best suited to be a single-time-point terminal assay or labor-intensive terminal immunostaining analysis. Here, we report integrated aptamer electrochemical sensors for on-chip, real-time monitoring of increases of cytochrome C, a cell death indicator, from intact microdissected tissues with high affinity and specificity. The platform features a multi-well sensor layout and a multiplexed electronic setup. The aptasensors measure increases in cytochrome C in the supernatant of mouse or human microdissected tumors after exposure to various drug treatments. Since the aptamer probe can be easily exchanged to recognize different targets, the platform could be adapted for multiplexed monitoring of various biomarkers, providing critical information on the tumor and its microenvironment. This approach could not only help develop more advanced cancer disease models but also apply to other complex in vitro disease models, such as organs-on-chips and organoids.

Patient-Derived Xenografts: A Valuable Preclinical Model for Drug Development and Biomarker Discovery

Patient-derived xenografts (PDXs), established by implanting patient tumor cells into immunodeficient mice, offer a platform for faithfully replicating human tumors. They closely mimic the histopathology, genomics, and drug sensitivity of patient tumors. This chapter highlights the versatile applications of PDXs, including studying tumor biology, metastasis, and chemoresistance, as well as their use in biomarker identification, drug screening, and personalized medicine. It also addresses challenges in using PDXs in cancer research, including variations in metastatic potential, lengthy establishment timelines, stromal changes, and limitations in immunocompromised models. Despite these challenges, PDXs remain invaluable tools guiding patient treatment and advancing preclinical drug development.

Azoxymethane/Dextran Sodium Sulfate (AOM/DSS) Model of Colorectal Cancer

Recent progress in developing new vaccination strategies against cancer requires the production of complex and reliable animal models reflecting the complexity of the tumors with their microenvironment. Mice can be considered a good source due to low cost and ease of being genetically modified, inoculated with tumor cell lines or treated by chemicals to induce different cancers. Despite significant limitations in modeling human cancer complexity, preclinical trials conducted in mice can efficiently contribute to understand molecular mechanisms of cancer, to closely resemble and follow carcinogenesis steps impossible to study into humans, and to test new anticancer therapies. In this chapter, we generally describe the different mouse models developed for cancer vaccines' preclinical trials. A particular focus is dedicated to a chemically-induced colorectal cancer model in use in our laboratories.

Mouse Melanoma Model in Tumor Vaccines and Immunotherapy Research

Efficacy of novel cancer immunization protocols could be tested in cell line-derived xenograft tumor models (CDX), which are based on the implantation of human tumor cell lines into mice for the development of different tumors by numerous means, such as subcutaneous implantation and orthotopic, venial, or peritoneal injections. However, the disadvantages of this model are the biological alteration of the derived cells or the inability of the cell lines to accurately reflect the complexity of tumor heterogeneity. Therefore, syngeneic mouse models, which offer a relatively simple grafting technique, preservation of lineage hierarchy, and the ability to generate tumors in as little as 2-8 weeks, are being used to study potential future applications in medical treatment, particularly immunotherapies. Here, we describe a B16.F10 C57Bl/6 mouse melanoma model we selected for therapeutic studies employing IL-2 and IL-12 immunization protocols. Procedure of tumor cells inoculation and melanoma development in mice is described in detail, as first and necessary set-up for successful immunization experiments.

Kidney Immune Cell Characterization of Humanized Mouse Models

Experimental studies often fail to translate to clinical practice. Humanized mouse models are an important tool to close this gap. We immunophenotyped the kidneys of NOG (EXL) and NSG mouse strains engrafted with human CD34 + hematopoietic stem cells or PBMCs and compared with immune cell composition of normal human kidney. Human CD34 + hematopoietic stem cell engraftment results in steady renal immune cell populations in mouse kidney with key similarities in composition compared with human kidney. Successful translation of experimental mouse data to human diseases is limited because of biological differences and imperfect disease models. Humanized mouse models are being used to bring murine models closer to humans. However, data for application in renal immune cell-mediated diseases are rare. We therefore studied immune cell composition of three different humanized mouse kidneys and compared them with human kidney. NOG and NOGEXL mice engrafted with human CD34 + hematopoietic stem cells were compared with NSG mice engrafted with human PBMCs. Engraftment was confirmed with flow cytometry, and immune cell composition in kidney, blood, spleen, and bone marrow was analyzed in different models. The results from immunophenotyping of kidneys from different humanized mouse strains were compared with normal portions of human kidneys. We found significant engraftment of human immune cells in blood and kidney of all tested models. huNSG mice showed highest frequencies of hTCR + cells compared with huNOG and huNOGEXL in blood. huNOGEXL was found to have the highest hCD4 + frequency among all tested models. Non-T cells such as hCD20 + and hCD11c + cells were decreased in huNSG mice compared with huNOG and huNOGEXL. Compared with normal human kidney, huNOG and huNOGEXL mice showed representative immune cell composition, rather than huNSG mice. In summary, humanization results in immune cell infiltration in the kidney with variable immune cell composition of tested humanized mouse models and partially reflects normal human kidneys, suggesting potential use for translational studies.

Development of Tumor Markers for Breast Cancer Immunotherapy

Although breast cancer treatment has been developed remarkably in recent years, it remains the primary cause of death among women. Immune checkpoint blockade therapy has significantly altered the way breast cancer is treated, although not all patients benefit from the changes. At present, the most effective mechanism of immune checkpoint blockade application in malignant tumors is not clear and efficacy may be influenced by many factors, including host, tumor, and tumor microenvironment dynamics. Therefore, there is a pressing need for tumor immunomarkers that can be used to screen patients and help determine which of them would benefit from breast cancer immunotherapy. At present, no single tumor marker can predict treatment efficacy with sufficient accuracy. Multiple markers may be combined to more accurately pinpoint patients who will respond favorably to immune checkpoint blockade medication. In this review, we have examined the breast cancer treatments, developments in research on the role of tumor markers in maximizing the clinical efficacy of immune checkpoint inhibitors, prospects for the identification of novel therapeutic targets, and the creation of individualized treatment plans. We also discuss how tumor markers can provide guidance for clinical practice.

Preclinical liver cancer models in the context of immunoprecision therapy: Application and perspectives

Hepatocellular carcinoma (HCC), ranking as the third leading cause of cancer-related mortality globally, continues to pose challenges in achieving optimal treatment outcomes. The complex nature of HCC, characterized by high spatiotemporal heterogeneity, invasive potential, and drug resistance, presents difficulties in its research. Consequently, an in-depth understanding and accurate simulation of the immune microenvironment of HCC are of paramount importance. This article comprehensively explores the application of preclinical models in HCC research, encompassing cell line models, patient-derived xenograft mouse models, genetically engineered mouse models, chemically induced models, humanized mouse models, organoid models, and microfluidic chip-based patient derived organotypic spheroids models. Each model possesses its distinct advantages and limitations in replicating the biological behavior and immune microenvironment of HCC. By scrutinizing the limitations of existing models, this paper aims to propel the development of next-generation cancer models, enabling more precise emulation of HCC characteristics. This will, in turn, facilitate the optimization of treatment strategies, drug efficacy prediction, and safety assessments, ultimately contributing to the realization of personalized and precision therapies. Additionally, this article also provides insights into future trends and challenges in the fields of tumor biology and preclinical research.

Engineered Adoptive T-Cell Therapies for Breast Cancer: Current Progress, Challenges, and Potential

Breast cancer remains a significant health challenge, and novel treatment approaches are critically needed. This review presents an in-depth analysis of engineered adoptive T-cell therapies (E-ACTs), an innovative frontier in cancer immunotherapy, focusing on their application in breast cancer. We explore the evolving landscape of chimeric antigen receptor (CAR) and T-cell receptor (TCR) T-cell therapies, highlighting their potential and challenges in targeting breast cancer. The review addresses key obstacles such as target antigen selection, the complex breast cancer tumor microenvironment, and the persistence of engineered T-cells. We discuss the advances in overcoming these barriers, including strategies to enhance T-cell efficacy. Finally, our comprehensive analysis of the current clinical trials in this area provides insights into the future possibilities and directions of E-ACTs in breast cancer treatment.

Preclinical evaluation of the efficacy of an antibody to human SIRPα for cancer immunotherapy in humanized mouse models

Tumor-associated macrophages (TAMs) are abundant in the tumor microenvironment and are considered potential targets for cancer immunotherapy. To examine the antitumor effects of agents targeting human TAMs in vivo, we here established preclinical tumor xenograft models based on immunodeficient mice that express multiple human cytokines and have been reconstituted with a human immune system by transplantation of human CD34+ hematopoietic stem and progenitor cells (HIS-MITRG mice). HIS-MITRG mice supported the growth of both human cell line (Raji)- and patient-derived B cell lymphoma as well as the infiltration of human macrophages into their tumors. We examined the potential antitumor action of an antibody to human SIRPα (SE12C3) that inhibits the interaction of CD47 on tumor cells with SIRPα on human macrophages and thereby promotes Fcγ receptor-mediated phagocytosis of the former cells by the latter. Treatment with the combination of rituximab (antibody to human CD20) and SE12C3 inhibited Raji tumor growth in HIS-MITRG mice to a markedly greater extent than did rituximab monotherapy. This enhanced antitumor effect was dependent on human macrophages and attributable to enhanced rituximab-dependent phagocytosis of lymphoma cells by human macrophages. Treatment with rituximab and SE12C3 also induced reprogramming of human TAMs toward a proinflammatory phenotype. Furthermore, the combination treatment essentially prevented the growth of patient-derived diffuse large B cell lymphoma in HIS-MITRG mice. Our findings thus support the study of HIS-MITRG mice as a model for the preclinical evaluation in vivo of potential therapeutics, such as antibodies to human SIRPα, that target human TAMs.

Expression of PD-1/PD-L1 axis in mediastinal lymph nodes and lung tissue of human and experimental lung fibrosis indicates a potential therapeutic target for idiopathic pulmonary fibrosis

BACKGROUND

Mediastinal lymph node enlargement is prevalent in patients with idiopathic pulmonary fibrosis (IPF). Studies investigating whether this phenomenon reflects specific immunologic activation are lacking.

METHODS

Programmed cell death-1 (PD-1)/ programmed cell death ligand-1 (PD-L1) expression in mediastinal lymph nodes and lung tissues was analyzed. PD-1, PD-L1 mRNA expression was measured in tracheobronchial lymph nodes of mice following bleomycin-induced injury on day 14. Finally, the effect of the PD-1 inhibitor, pembrolizumab, in bleomycin-induced pulmonary fibrosis was investigated.

RESULTS

We analyzed mediastinal lymph nodes of thirty-three patients (n = 33, IPF: n = 14, lung cancer: n = 10, concomitant IPF and lung cancer: n = 9) and lung tissues of two hundred nineteen patients (n = 219, IPF: 123, controls: 96). PD-1 expression was increased, while PD-L1 expression was decreased, in mediastinal lymph nodes of patients with IPF compared to lung cancer and in IPF lungs compared to control lungs. Tracheobronchial lymph nodes isolated on day 14 from bleomycin-treated mice exhibited increased size and higher PD-1, PD-L1 mRNA levels compared to saline-treated animals. Pembrolizumab blunted bleomycin-induced lung fibrosis, as indicated by reduction in Ashcroft score and improvement in respiratory mechanics.

CONCLUSIONS

Mediastinal lymph nodes of patients with IPF exhibit differential expression profiles than those of patients with lung cancer indicating distinct immune-mediated pathways regulating fibrogenesis and carcinogenesis. PD-1 expression in mediastinal lymph nodes is in line with lung tissue expression. Lower doses of pembrolizumab might exert antifibrotic effects. Clinical trials aiming to endotype patients based on mediastinal lymph node profiling and accordingly implement targeted therapies such as PD-1 inhibitors are greatly anticipated.

Preclinical Models of Visceral Sarcomas

Visceral sarcomas are a rare malignant subgroup of soft tissue sarcomas (STSs). STSs, accounting for 1% of all adult tumors, are derived from mesenchymal tissues and exhibit a wide heterogeneity. Their rarity and the high number of histotypes hinder the understanding of tumor development mechanisms and negatively influence clinical outcomes and treatment approaches. Although some STSs (~20%) have identifiable genetic markers, as specific mutations or translocations, most are characterized by complex genomic profiles. Thus, identification of new therapeutic targets and development of personalized therapies are urgent clinical needs. Although cell lines are useful for preclinical investigations, more reliable preclinical models are required to develop and test new potential therapies. Here, we provide an overview of the available in vitro and in vivo models of visceral sarcomas, whose gene signatures are still not well characterized, to highlight current challenges and provide insights for future studies.

Antitumor activity of pegylated human interferon β as monotherapy or in combination with immune checkpoint inhibitors via tumor growth inhibition and dendritic cell activation

Type I interferons (IFN), especially human IFN alpha (IFNα), have been utilized for antitumor therapy for decades. Human interferon beta (IFNβ) is rarely used for cancer treatment, despite advantages over IFNα in biological activities such as tumor growth inhibition and dendritic cell (DC) activation. The utilization of pegylated human IFNβ (PEG-IFNβ), as monotherapy or in combination with immune checkpoint inhibitors (ICIs) was evaluated in this study through in vivo efficacy studies in syngeneic mouse melanoma, non-small cell lung cancer (NSCLC), and colon adenocarcinoma (COAD) models resistant to immune checkpoint inhibitors (ICIs). In vitro comparative study of PEG-IFNβ and pegylated IFNα-2b was performed in terms of tumor growth inhibition against human melanoma, NSCLC and COAD cell lines and activation of human monocyte-derived DCs (MoDCs). Our data demonstrate that the in vivo antitumor effects of PEG-IFNβ are partially attributable to tumor growth-inhibitory effects and DC-activating activities, superior to pegylated IFNα-2b. Our findings suggest that utilizing PEG-IFNβ as an antitumor therapy can enhance the therapeutic effect of ICIs in ICI-resistant tumors by directly inhibiting tumor growth and induction of DC maturation.

Physical activity regulates the immune response to breast cancer by a hematopoietic stem cell-autonomous mechanism

Physical activity is a modifiable lifestyle factor that is associated with a decreased risk for the development of breast cancer. While the exact mechanisms for the reduction in cancer risk due to physical activity are largely unknown, it is postulated that the biological reduction in cancer risk is driven by improvements in inflammation and immune function with exercise. Hematopoietic stem cells (HSCs) are the progenitor for all of the cells of the immune system and are involved in cancer immunosurveillance through differentiation into cytotoxic cell population. In this study, we investigate the role of physical activity (PA) in a spontaneously occurring model of breast cancer over time, with a focus on tumor incidence, circulating and tumor-infiltrating immune cells as well gene expression profiles of tumors and hematopoietic stem cells. Furthermore, we show that, in addition to a direct effect of PA on the immune cells of tumor-bearing mice, PA reduces the oxidative stress in HSCs of wildtype and tumor-bearing mice, and by doing so, alters the differentiation of the HSCs towards T cells in order to enhance cancer immunosurveillance.

Advancing translational research for colorectal immuno-oncology

Colorectal cancer (CRC) is a common and deadly disease. Unfortunately, immune checkpoint inhibitors (ICIs) fail to elicit effective anti-tumour responses in the vast majority of CRC patients. Patients that are most likely to respond are those with DNA mismatch repair deficient (dMMR) and microsatellite instability (MSI) disease. However, reliable predictors of ICI response are lacking, even within the dMMR/MSI subtype. This, together with identification of novel mechanisms to increase response rates and prevent resistance, are ongoing and vitally important unmet needs. To address the current challenges with translation of early research findings into effective therapeutic strategies, this review summarises the present state of preclinical testing used to inform the development of immuno-regulatory treatment strategies for CRC. The shortfalls and advantages of commonly utilised mouse models of CRC, including chemically induced, transplant and transgenic approaches are highlighted. Appropriate use of existing models, incorporation of patient-derived data and development of cutting-edge models that recapitulate important features of human disease will be key to accelerating clinically relevant research in this area.