Advances and challenges of CAR T therapy and suitability of animal models (Review)

Overcoming chimeric antigen receptor-T (CAR-T) resistance with checkpoint inhibitors: Existing methods, challenges, clinical success, and future prospects: A comprehensive review

Immune checkpoint blockade is, as of today, the most successful form of cancer immunotherapy, with more than 43 % of cancer patients in the US eligible to receive it; however, only up to 12.5 % of patients respond to it. Similarly, adoptive cell therapy using bioengineered chimeric antigen receptorT (CAR-T) cells and T-cell receptor (TCR-T) cells has provided excellent responses against liquid tumours, but both forms of immunotherapy have encountered challenges within a tumour microenvironment that is both lacks of tumour-specific T-cells and strongly immunosuppressive toward externally administered CAR-T and TCR-T cells. This review focuses on understanding approved checkpoint blockade and adoptive cell therapy at both biological and clinical levels before delving into how and why their combination holds significant promise in overcoming their individual shortcomings. The advent of next-generation checkpoint inhibitors has further strengthened the immune checkpoint field, and a special section explores how these inhibitors can address existing hurdles in combining checkpoint blockade with adoptive cell therapy and homing in on our cancer target for long-term immunity.

A Pathologist's Guide to Non-clinical Safety Assessment of Adoptive Cell Therapy Products

Through two decades of research and development, adoptive cell therapies (ACTs) have revolutionized treatment for hematologic malignancies. Many of the seven US Food and Drug Administration (FDA)-approved products are proven to be a curative last line of defense against said malignancies. The ACTs, known more commonly as chimeric antigen receptor (CAR) T-cells, utilize engineered lymphocytes to target and destroy cancer cells in a patient-specific, major histocompatibility complex (MHC)-independent manner, acting as "living drugs" that adapt to and surveil the body post-treatment. Despite their efficacy, CAR T-cell therapies present unique challenges in preclinical safety assessment. The safety and pharmacokinetics of CAR T-cells are influenced by numerous factors including donor and recipient characteristics, product design, and manufacturing processes that are not well-predicted by existing in vitro and in vivo preclinical safety models. The CAR therapy-mediated toxicities in clinical settings primarily arise from unintended targeting of non-tumor cells, potential tumorigenicity, and severe immune activation syndromes like cytokine release syndrome and immune effector cell-associated neurotoxicity. Addressing these issues necessitates a deep understanding of CAR target expression in normal tissues, inclusive of the spatial microanatomical distribution, off-target screening, and a deep understanding CAR cell manufacturing practices and immunopathology.

TCR-T cell therapy: current development approaches, preclinical evaluation, and perspectives on regulatory challenges

TCR-T cell therapy represents a promising advancement in adoptive immunotherapy for cancer treatment. Despite its potential, the development and preclinical testing of TCR-T cells face significant challenges. This review provides a structured overview of the key stages in preclinical testing, including in silico, in vitro, and in vivo methods, within the context of the sequential development of novel therapies. This review aimed to systematically outline the processes for evaluating TCR-T cells at each stage: from in silico approaches used to predict target antigens, assess cross-reactivity, and minimize off-target effects, to in vitro assays designed to measure cell functionality, cytotoxicity, and activation. Additionally, the review discusses the limitations of in vivo testing in animal models, particularly in accurately reflecting the human tumor microenvironment and immune responses. Performed analysis emphasizes the importance of these preclinical stages in the safe and effective development of TCR-T cell therapies. While current models provide valuable insights, we identify critical gaps, particularly in in vivo biodistribution and toxicity assessments, and propose the need for enhanced standardization and the development of more representative models. This structured approach aims to improve the predictability and safety of TCR-T cell therapy as it advances towards clinical application.

The efficacy and applicability of chimeric antigen receptor (CAR) T cell-based regimens for primary bone tumors: A comprehensive review of current evidence

Primary bone tumors (PBT), although rare, could pose significant mortality and morbidity risks due to their high incidence of lung metastasis. Survival rates of patients with PBTs may vary based on the tumor type, therapeutic interventions, and the time of diagnosis. Despite advances in the management of patients with these tumors over the past four decades, the survival rates seem not to have improved significantly, implicating the need for novel therapeutic interventions. Surgical resection with wide margins, radiotherapy, and systemic chemotherapy are the main lines of treatment for PBTs. Neoadjuvant and adjuvant chemotherapy, along with emerging immunotherapeutic approaches such as chimeric antigen receptor (CAR)-T cell therapy, have the potential to improve the treatment outcomes for patients with PBTs. CAR-T cell therapy has been introduced as an option in hematologic malignancies, with FDA approval for several CD19-targeting CAR-T cell products. This review aims to highlight the potential of immunotherapeutic strategies, specifically CAR T cell therapy, in managing PBTs.

CAR T treatment beyond cancer: Hope for immunomodulatory therapy of non-cancerous diseases

Engineering a patient's own T cells to accurately identify and eliminate cancer cells has effectively cured individuals afflicted with previously incurable hematologic cancers. These findings have stimulated research into employing chimeric antigen receptor (CAR) T therapy across various areas within the field of oncology. However, evidence from both clinical and preclinical investigations emphasize the broader potential of CAR T therapy, extending beyond oncology to address autoimmune disorders, persistent infections, cardiac fibrosis, age-related ailments and other conditions. Concurrently, the advent of novel technologies and platforms presents additional avenues for utilizing CAR T therapy in non-cancerous contexts. This review provides an overview of the rationale behind CAR T therapy, delineates ongoing challenges in its application to cancer treatment, summarizes recent findings in non-cancerous diseases, and engages in discourse regarding emerging technologies that bear relevance. The review delves into prospective applications of this therapeutic approach across a diverse range of scenarios. Lastly, the review underscores concerns related to precision and safety, while also outlining the envisioned trajectory for extending CAR T therapy beyond cancer treatment.

Canine Mammary Tumors: Classification, Biomarkers, Traditional and Personalized Therapies

In recent years, many studies have focused their attention on the dog as a proper animal model for human cancer. In dogs, mammary tumors develop spontaneously, involving a complex interplay between tumor cells and the immune system and revealing several molecular and clinical similarities to human breast cancer. In this review, we summarized the major features of canine mammary tumor, risk factors, and the most important biomarkers used for diagnosis and treatment. Traditional therapy of mammary tumors in dogs includes surgery, which is the first choice, followed by chemotherapy, radiotherapy, or hormonal therapy. However, these therapeutic strategies may not always be sufficient on their own; advancements in understanding cancer mechanisms and the development of innovative treatments offer hope for improved outcomes for oncologic patients. There is still a growing interest in the use of personalized medicine, which should play an irreplaceable role in the research not only in human cancer therapy, but also in veterinary oncology. Moreover, immunotherapy may represent a novel and promising therapeutic option in canine mammary cancers. The study of novel therapeutic approaches is essential for future research in both human and veterinary oncology.

Managing the immune microenvironment of osteosarcoma: the outlook for osteosarcoma treatment

Osteosarcoma, with poor survival after metastasis, is considered the most common primary bone cancer in adolescents. Notwithstanding the efforts of researchers, its five-year survival rate has only shown limited improvement, suggesting that existing therapeutic strategies are insufficient to meet clinical needs. Notably, immunotherapy has shown certain advantages over traditional tumor treatments in inhibiting metastasis. Therefore, managing the immune microenvironment in osteosarcoma can provide novel and valuable insight into the multifaceted mechanisms underlying the heterogeneity and progression of the disease. Additionally, given the advances in nanomedicine, there exist many advanced nanoplatforms for enhanced osteosarcoma immunotherapy with satisfactory physiochemical characteristics. Here, we review the classification, characteristics, and functions of the key components of the immune microenvironment in osteosarcoma. This review also emphasizes the application, progress, and prospects of osteosarcoma immunotherapy and discusses several nanomedicine-based options to enhance the efficiency of osteosarcoma treatment. Furthermore, we examine the disadvantages of standard treatments and present future perspectives for osteosarcoma immunotherapy.

Comparative Evaluation of Tumor-Infiltrating Lymphocytes in Companion Animals: Immuno-Oncology as a Relevant Translational Model for Cancer Therapy

Despite the important role of preclinical experiments to characterize tumor biology and molecular pathways, there are ongoing challenges to model the tumor microenvironment, specifically the dynamic interactions between tumor cells and immune infiltrates. Comprehensive models of host-tumor immune interactions will enhance the development of emerging treatment strategies, such as immunotherapies. Although in vitro and murine models are important for the early modelling of cancer and treatment-response mechanisms, comparative research studies involving veterinary oncology may bridge the translational pathway to human studies. The natural progression of several malignancies in animals exhibits similar pathogenesis to human cancers, and previous studies have shown a relevant and evaluable immune system. Veterinary oncologists working alongside oncologists and cancer researchers have the potential to advance discovery. Understanding the host-tumor-immune interactions can accelerate drug and biomarker discovery in a clinically relevant setting. This review presents discoveries in comparative immuno-oncology and implications to cancer therapy.