T-cells engineered with a novel VHH-based chimeric antigen receptor against CD19 exhibit comparable tumoricidal efficacy to their FMC63-based counterparts

Influencing factors and solution strategies of chimeric antigen receptor T-cell therapy (CAR-T) cell immunotherapy

Chimeric antigen receptor T-cesll therapy (CAR-T) has achieved groundbreaking advancements in clinical application, ushering in a new era for innovative cancer treatment. However, the challenges associated with implementing this novel targeted cell therapy are increasingly significant. Particularly in the clinical management of solid tumors, obstacles such as the immunosuppressive effects of the tumor microenvironment, limited local tumor infiltration capability of CAR-T cells, heterogeneity of tumor targeting antigens, uncertainties surrounding CAR-T quality, control, and clinical adverse reactions have contributed to increased drug resistance and decreased compliance in tumor therapy. These factors have significantly impeded the widespread adoption and utilization of this therapeutic approach. In this paper, we comprehensively analyze recent preclinical and clinical reports on CAR-T therapy while summarizing crucial factors influencing its efficacy. Furthermore, we aim to identify existing solution strategies and explore their current research status. Through this review article, our objective is to broaden perspectives for further exploration into CAR-T therapy strategies and their clinical applications.

Humanization of the antigen-recognition domain does not impinge on the antigen-binding, cytokine secretion, and antitumor reactivity of humanized nanobody-based CD19-redirected CAR-T cells

BACKGROUND

The immunogenicity of the antigen-recognition domains of chimeric antigen receptor (CAR)-T cells leads to immune responses that may compromise the antitumor effects of the adoptively transferred T cells. Herein, we attempt to humanize a CD19-specific VHH (named H85) using in silico techniques and investigate the impact of antigen-recognition domain humanization on CAR expression and density, cytokine secretion, and cytolytic reactivity of CAR-T cells based on the humanized VHH.

METHODS

H85 was humanized (named HuH85), and then HuH85 was compared with H85 in terms of conformational structure, physicochemical properties, antigenicity and immunogenicity, solubility, flexibility, stability, and CD19-binding capacity using in silico techniques. Next, H85CAR-T cells and HuH85CAR-T cells were developed and CAR expression and surface density were assessed via flow cytometry. Ultimately, the antitumor reactivity and secreted levels of IFN-γ, IL-2, and TNF-α were assessed following the co-cultivation of the CAR-T cells with Ramos, Namalwa, and K562 cells.

RESULTS

In silico findings demonstrated no negative impacts on HuH85 as a result of humanization. Ultimately, H85CAR and HuH85CAR could be surface-expressed on transduced T cells at comparable levels as assessed via mean fluorescence intensity. Moreover, H85CAR-T cells and HuH85CAR-T cells mediated comparable antitumor effects against Ramos and Namalwa cells and secreted comparable levels of IFN-γ, IL-2, and TNF-α following co-cultivation.

CONCLUSION

HuH85 can be used to develop immunotherapeutics against CD19-associated hematologic malignancies. Moreover, HuH85CAR-T cells must be further investigated in vitro and in preclinical xenograft models of CD19+ leukemias and lymphomas before advancing into clinical trials.

Universal CAR 2.0 to overcome current limitations in CAR therapy

Chimeric antigen receptor (CAR) T cell therapy has effectively complemented the treatment of advanced relapsed and refractory hematological cancers. The remarkable achievements of CD19- and BCMA-CAR T therapies have raised high expectations within the fields of hematology and oncology. These groundbreaking successes are propelling a collective aspiration to extend the reach of CAR therapies beyond B-lineage malignancies. Advanced CAR technologies have created a momentum to surmount the limitations of conventional CAR concepts. Most importantly, innovations that enable combinatorial targeting to address target antigen heterogeneity, using versatile adapter CAR concepts in conjunction with recent transformative next-generation CAR design, offer the promise to overcome both the bottleneck associated with CAR manufacturing and patient-individualized treatment regimens. In this comprehensive review, we delineate the fundamental prerequisites, navigate through pivotal challenges, and elucidate strategic approaches, all aimed at paving the way for the future establishment of multitargeted immunotherapies using universal CAR technologies.

Scrutiny of chimeric antigen receptor activation by the extracellular domain: experience with single domain antibodies targeting multiple myeloma cells highlights the need for case-by-case optimization

Introduction

Multiple myeloma (MM) remains incurable, despite the advent of chimeric antigen receptor (CAR)-T cell therapy. This unfulfilled potential can be attributed to two untackled issues: the lack of suitable CAR targets and formats. In relation to the former, the target should be highly expressed and reluctant to shedding; two characteristics that are attributed to the CS1-antigen. Furthermore, conventional CARs rely on scFvs for antigen recognition, yet this withholds disadvantages, mainly caused by the intrinsic instability of this format. VHHs have been proposed as valid scFv alternatives. We therefore intended to develop VHH-based CAR-T cells, targeting CS1, and to identify VHHs that induce optimal CAR-T cell activation together with the VHH parameters required to achieve this.

Methods

CS1-specific VHHs were generated, identified and fully characterized, in vitro and in vivo. Next, they were incorporated into second-generation CARs that only differ in their antigen-binding moiety. Reporter T-cell lines were lentivirally transduced with the different VHH-CARs and CAR-T cell activation kinetics were evaluated side-by-side. Affinity, cell-binding capacity, epitope location, in vivo behavior, binding distance, and orientation of the CAR-T:MM cell interaction pair were investigated as predictive parameters for CAR-T cell activation.

Results

Our data show that the VHHs affinity for its target antigen is relatively predictive for its in vivo tumor-tracing capacity, as tumor uptake generally decreased with decreasing affinity in an in vivo model of MM. This does not hold true for their CAR-T cell activation potential, as some intermediate affinity-binding VHHs proved surprisingly potent, while some higher affinity VHHs failed to induce equal levels of T-cell activation. This could not be attributed to cell-binding capacity, in vivo VHH behavior, epitope location, cell-to-cell distance or binding orientation. Hence, none of the investigated parameters proved to have significant predictive value for the extent of CAR-T cell activation.

Conclusions

We gained insight into the predictive parameters of VHHs in the CAR-context using a VHH library against CS1, a highly relevant MM antigen. As none of the studied VHH parameters had predictive value, defining VHHs for optimal CAR-T cell activation remains bound to serendipity. These findings highlight the importance of screening multiple candidates.

Adoptive T cell therapy for solid tumors: current landscape and future challenges

Adoptive cell therapy (ACT) comprises different strategies to enhance the activity of T lymphocytes and other effector cells that orchestrate the antitumor immune response, including chimeric antigen receptor (CAR) T-cell therapy, T-cell receptor (TCR) gene-modified T cells, and therapy with tumor-infiltrating lymphocytes (TILs). The outstanding results of CAR-T cells in some hematologic malignancies have launched the investigation of ACT in patients with refractory solid malignancies. However, certain characteristics of solid tumors, such as their antigenic heterogeneity and immunosuppressive microenvironment, hamper the efficacy of antigen-targeted treatments. Other ACT modalities, such as TIL therapy, have emerged as promising new strategies. TIL therapy has shown safety and promising activity in certain immunogenic cancers, mainly advanced melanoma, with an exciting rationale for its combination with immune checkpoint inhibitors. However, the implementation of TIL therapy in clinical practice is hindered by several biological, logistic, and economic challenges. In this review, we aim to summarize the current knowledge, available clinical results, and potential areas of future research regarding the use of T cell therapy in patients with solid tumors.

Biosynthesis cobalt-doped nickel nanoparticles and their toxicity against disease

The nanostructures have the great potential for novel medical and drug delivery applications. In present paper a green approach for the preparation of pure nickel oxide (NiO) and 5% cobalt-doped NiO (Co╫NiO) nanoparticles (NPs) by using Prosopis fracta extract have been study. The product of Co╫NiO NPs was proved through the PXRD, Raman, UV-Vis, FESEM, and EDX analyses. The results of XRD, EDX, and UV-Visible spectra displayed well doped cobalt in NiO NP. The particle sizes of Co╫NiO NPs were observed to be about 80 nm. The MTT test results for the cytotoxicity of Co╫NiO NPs on breast cancer cells (MCF-7) affirmed the stronger impact of doped NiO-NPs on cancer cells compared to NiO NPs. Thus, it is indicated that the doping process on NiO NPs caused an increase in its inhibitory effect against MCF-7 cells. RESEARCH HIGHLIGHTS: Cobalt-doped NiO nanoparticles were prepared using ecofriendly synthesis method and their cytotoxicity studied against MCF-7 cells.

Characterization of novel CD19-specific VHHs isolated from a camelid immune library by phage display

BACKGROUND

Monoclonal antibody (mAb)-based immunotherapies have achieved promising outcomes in the treatment of immunological and oncological indications. CD19 is considered one of the most qualified antigens in the treatment of B-cell neoplasms. VHHs (nanobodies) are known for their physicochemical advantages over conventional mAbs rendering them suitable therapeutics and diagnostic tools. Herein, we aimed to isolate CD19-specific VHHs from a novel immune library using phage display.

METHODS

An immune VHH gene library was constructed. Using phage display and after five biopanning rounds, two monoclonal CD19-specific VHHs were isolated. The selected VHHs were expressed, purified, and characterized in terms of their affinity, specificity, sensitivity, and ability to target CD19-positive cell lines. Moreover, in silico analyses were employed for further characterization.

RESULTS

A VHH library was developed, and because the outputs of the 4th biopanning round exhibited the most favorable characteristics, a panel of random VHHs was selected from them. Ultimately, two of the most favorable VHHs were selected and DNA sequenced (designated as GR37 and GR41). Precise experiments indicated that GR37 and GR41 exhibited considerable specificity, sensitivity, and affinity (1.15 × 107 M-1 and 2.08 × 107 M-1, respectively) to CD19. Flow cytometric analyses revealed that GR37 and GR41 could bind CD19 on the surface of cell lines expressing the antigen. Moreover, in silico experiments predicted that both VHHs target epitopes that are distinct from that targeted by the CD19-specific single-chain variable fragment (scFv) FMC63.

CONCLUSION

The selected VHHs can be used as potential targeting tools for the development of CD19-based immunotherapeutics.

CAR-T cell immunotherapy for ovarian cancer: hushing the silent killer

As the most lethal gynecologic oncological indication, carcinoma of the ovary has been ranked as the 5th cause of cancer-related mortality in women, with a high percentage of the patients being diagnosed at late stages of the disease and a five-year survival of ~ 30%. Ovarian cancer patients conventionally undergo surgery for tumor removal followed by platinum- or taxane-based chemotherapy; however, a high percentage of patients experience tumor relapse. Cancer immunotherapy has been regarded as a silver lining in the treatment of patients with various immunological or oncological indications; however, mirvetuximab soravtansine (a folate receptor α-specific mAb) and bevacizumab (a VEGF-A-specific mAb) are the only immunotherapeutics approved for the treatment of ovarian cancer patients. Chimeric antigen receptor T-cell (CAR-T) therapy has achieved tremendous clinical success in the treatment of patients with certain B-cell lymphomas and leukemias, as well as multiple myeloma. In the context of solid tumors, CAR-T therapies face serious obstacles that limit their therapeutic benefit. Such hindrances include the immunosuppressive nature of solid tumors, impaired tumor infiltration, lack of qualified tumor-associated antigens, and compromised stimulation and persistence of CAR-Ts following administration. Over the past years, researchers have made arduous attempts to apply CAR-T therapy to ovarian cancer. In this review, we outline the principles of CAR-T therapy and then highlight its limitations in the context of solid tumors. Ultimately, we focus on preclinical and clinical findings achieved in CAR-T-mediated targeting of different ovarian cancer-associated target antigens.

Site-specific transgene integration in chimeric antigen receptor (CAR) T cell therapies

Chimeric antigen receptor (CAR) T cells and natural killer (NK) cells are genetically engineered immune cells that can detect target antigens on the surface of target cells and eliminate them following adoptive transfer. Recent progress in CAR-based therapies has led to outstanding clinical success in certain patients with leukemias and lymphomas and offered therapeutic benefits to those resistant to conventional therapies. The universal approach to stable CAR transgene delivery into the T/NK cells is the use of viral particles. Such approaches mediate semi-random transgene insertions spanning the entire genome with a high preference for integration into sites surrounding highly-expressed genes and active loci. Regardless of the variable CAR expression level based on the integration site of the CAR transgene, foreign integrated DNA fragments may affect the neighboring endogenous genes and chromatin structure and potentially change a transduced T/NK cell behavior and function or even favor cellular transformation. In contrast, site-specific integration of CAR constructs using recent genome-editing technologies could overcome the limitations and disadvantages of universal random gene integration. Herein, we explain random and site-specific integration of CAR transgenes in CAR-T/NK cell therapies. Also, we tend to summarize the methods for site-specific integration as well as the clinical outcomes of certain gene disruptions or enhancements due to CAR transgene integration. Also, the advantages and limitations of using site-specific integration methods are discussed in this review. Ultimately, we will introduce the genomic safe harbor (GSH) standards and suggest some appropriate safety prospects for CAR integration in CAR-T/NK cell therapies.

Site-specific transgene integration in chimeric antigen receptor (CAR) T cell therapies

Chimeric antigen receptor (CAR) T cells and natural killer (NK) cells are genetically engineered immune cells that can detect target antigens on the surface of target cells and eliminate them following adoptive transfer. Recent progress in CAR-based therapies has led to outstanding clinical success in certain patients with leukemias and lymphomas and offered therapeutic benefits to those resistant to conventional therapies. The universal approach to stable CAR transgene delivery into the T/NK cells is the use of viral particles. Such approaches mediate semi-random transgene insertions spanning the entire genome with a high preference for integration into sites surrounding highly-expressed genes and active loci. Regardless of the variable CAR expression level based on the integration site of the CAR transgene, foreign integrated DNA fragments may affect the neighboring endogenous genes and chromatin structure and potentially change a transduced T/NK cell behavior and function or even favor cellular transformation. In contrast, site-specific integration of CAR constructs using recent genome-editing technologies could overcome the limitations and disadvantages of universal random gene integration. Herein, we explain random and site-specific integration of CAR transgenes in CAR-T/NK cell therapies. Also, we tend to summarize the methods for site-specific integration as well as the clinical outcomes of certain gene disruptions or enhancements due to CAR transgene integration. Also, the advantages and limitations of using site-specific integration methods are discussed in this review. Ultimately, we will introduce the genomic safe harbor (GSH) standards and suggest some appropriate safety prospects for CAR integration in CAR-T/NK cell therapies.

Novel chimeric antigen receptor T cell-based immunotherapy: a perspective for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is highly aggressive and does not express estrogen receptor (ER), progesterone (PR), or human epidermal growth factor receptor 2 (HER2). It has a poor prognosis, and traditional endocrine and anti-HER2 targeted therapies have low efficacy against it. In contrast, surgery, radiotherapy, and/or systemic chemotherapy are relatively effective at controlling TNBC. The resistance of TNBC to currently available clinical therapies has had a significantly negative impact on its treatment outcomes. Hence, new therapeutic options are urgently required. Chimeric antigen receptor T cell (CAR-T) therapy is a type of immunotherapy that integrates the antigen specificity of antibodies and the tumor-killing effect of T cells. CAR-T therapy has demonstrated excellent clinical efficacy against hematological cancers. However, its efficacy against solid tumors such as TNBC is inadequate. The present review aimed to investigate various aspects of CAR-T administration as TNBC therapy. We summarized the potential therapeutic targets of CAR-T that were identified in preclinical studies and clinical trials on TNBC. We addressed the limitations of using CAR-T in the treatment of TNBC in particular and solid tumors in general and explored key strategies to overcome these impediments. Finally, we comprehensively examined the advancement of CAR-T immunotherapy as well as countermeasures that could improve its efficacy as a TNBC treatment and the prognosis of patients with this type of cancer.

Effectiveness and safety of anti-BCMA chimeric antigen receptor T-cell treatment in relapsed/refractory multiple myeloma: a comprehensive review and meta-analysis of prospective clinical trials

Background: Chimeric antigen receptor T cells treatment targeting B cell maturation antigen (BCMA) is an emerging treatment option for relapsed/refractory multiple myeloma (RRMM) and has demonstrated outstanding outcomes in clinical studies. Objective: The aim of this comprehensive review and meta-analysis was to summarize the effectiveness and safety of anti-BCMA CAR-T treatment for patients with relapsed/refractory multiple myeloma (RRMM). Our research identifies variables influencing outcome measures to provide additional evidence for CAR-T product updates, clinical trial design, and clinical treatment guidance. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard was followed for conducting this comprehensive review and meta-analysis, which was submitted to PROSPERO (CRD42023390037). From the inception of the study until 10 September 2022, PubMed, Web of Science, EMBASE, the Cochrane Library, CNKI, and WanFang databases were searched for eligible studies. Stata software (version 16.0) was used to assess effectiveness and safety outcomes. Results: Out of 875 papers, we found 21 relevant trials with 761 patients diagnosed as RRMM and were given anti-BCMA CAR-T treatment. The overall response rate (ORR) for the entire sample was 87% (95% CI: 80-93%) complete response rate (CRR) was 44% (95% CI: 34-54%). The minimal residual disease (MRD) negativity rate within responders was 78% (95% CI: 65-89%). The combined incidence of cytokine release syndrome was 82% (95% CI: 72-91%) and neurotoxicity was 10% (95% CI: 5%-17%). The median progression-free survival (PFS) was 8.77 months (95% CI: 7.48-10.06), the median overall survival (OS) was 18.87 months (95% CI: 17.20-20.54) and the median duration of response (DOR) was 10.32 months (95% CI: 9.34-11.31). Conclusion: According to this meta-analysis, RRMM patients who received anti-BCMA CAR-T treatment have demonstrated both effectiveness and safety. Subgroup analysis confirmed the anticipated inter-study heterogeneity and pinpointed potential factors contributing to safety and efficacy, which may help with the development of CAR-T cell studies and lead to optimized BCMA CAR-T-cell products. Systematic Review Registration: Clinicaltrials.gov, PROSPERO, CRD42023390037.