A high throughput microelectroporation device to introduce a chimeric antigen receptor to redirect the specificity of human T cells

Automating CAR-T Transfection with Micro and Nano-Technologies

Cancer poses a significant health challenge, with traditional treatments like surgery, radiotherapy, and chemotherapy often lacking in cell specificity and long-term curative potential. Chimeric antigen receptor T cell (CAR-T) therapy,utilizing genetically engineered T cells to target cancer cells, is a promising alternative. However, its high cost limits widespread application. CAR-T manufacturing process encompasses three stages: cell isolation and activation, transfection, and expansion.While the first and last stages have straightforward, commercially available automation technologies, the transfection stage lags behind. Current automated transfection relies on viral vectors or bulk electroporation, which have drawbacks such as limited cargo capacity and significant cell disturbance. Conversely, micro and nano-tool methods offer higher throughput and cargo flexibility, yet their automation remains underexplored.In this perspective, the progress in micro and nano-engineering tools for CAR-T transfection followed by a discussion to automate them is described. It is anticipated that this work can inspire the community working on micro and nano transfection techniques to examine how their protocols can be automated to align with the growing interest in automating CAR-T manufacturing.

Cellular Cancer Immunotherapy Development and Manufacturing in the Clinic

The transfusion of naturally derived or modified cellular therapies, referred to as adoptive cell therapy (ACT), has demonstrated clinical efficacy in the treatment of hematologic malignancies and metastatic melanoma. In addition, cellular vaccination, such as dendritic cell-based cancer vaccines, continues to be actively explored. The manufacturing of these therapies presents a considerable challenge to expanding the use of ACT as a viable treatment modality, particularly at academic production facilities. Furthermore, the expanding commercial interest in ACT presents new opportunities as well as strategic challenges for the future vision of cellular manufacturing in academic centers. Current trends in the production of ACT at tertiary care centers and prospects for improved manufacturing practices that will foster further clinical benefit are reviewed herein.

Chimeric antigen receptor (CAR) immunotherapy: basic principles, current advances, and future prospects in neuro-oncology

With recent advances, chimeric antigen receptor (CAR) immunotherapy has become a promising modality for patients with refractory cancer diseases. The successful results of CAR T cell therapy in relapsed and refractory B-cell malignancies shifted the paradigm of cancer immunotherapy by awakening the scientific, clinical, and commercial interest in translating this technology for the treatment of solid cancers. This review elaborates on fundamental principles of CAR T cell therapy (development of CAR construct, challenges of CAR T cell therapy) and its application on solid tumors as well as CAR T cell therapy potential in the field of neuro-oncology. Glioblastoma (GBM) is identified as one of the most challenging solid tumors with a permissive immunological milieu and dismal prognosis. Standard multimodal treatment using maximal safe resection, radiochemotherapy, and maintenance chemotherapy extends the overall survival beyond a year. Recurrence is, however, inevitable. GBM holds several unique features including its vast intratumoral heterogeneity, immunosuppressive environment, and a partially permissive anatomic blood–brain barrier, which offers a unique opportunity to investigate new treatment approaches. Tremendous efforts have been made in recent years to investigate novel CAR targets and target combinations with standard modalities for solid tumors and GBM to improve treatment efficacy. In this review, we outline the history of CAR immunotherapy development, relevant CAR target antigens validated with CAR T cells as well as preclinical approaches in combination with adjunct approaches via checkpoint inhibition, bispecific antibodies, and second-line systemic therapies that enhance anticancer efficacy of the CAR-based cancer immunotherapy.

Non-viral transfection technologies for next-generation therapeutic T cell engineering

Genetically engineered T cells have sparked interest in advanced cancer treatment, reaching a milestone in 2017 with two FDA-approvals for CD19-directed chimeric antigen receptor (CAR) T cell therapeutics. It is becoming clear that the next generation of CAR T cell therapies will demand more complex engineering strategies and combinations thereof, including the use of revolutionary gene editing approaches. To date, manufacturing of CAR T cells mostly relies on γ-retroviral or lentiviral vectors, but their use is associated with several drawbacks, including safety issues, high manufacturing cost and vector capacity constraints. Non-viral approaches, including membrane permeabilization and carrier-based techniques, have therefore gained a lot of interest to replace viral transductions in the manufacturing of T cell therapeutics. This review provides an in-depth discussion on the avid search for alternatives to viral vectors, discusses key considerations for T cell engineering technologies, and provides an overview of the emerging spectrum of non-viral transfection technologies for T cells. Strengths and weaknesses of each technology will be discussed in relation to T cell engineering. Altogether, this work emphasizes the potential of non-viral transfection approaches to advance the next-generation of genetically engineered T cells.

High-Throughput and Self-Powered Electroporation System for Drug Delivery Assisted by Microfoam Electrode

Electroporation is an effective approach for drug and gene delivery, but it is still limited by its low-throughput and severe cell damage. Herein, with a self-powered triboelectric nanogenerator as the power source, we demonstrated a high-throughput electroporation system based on the design of biocompatible and flexible polypyrrole microfoam as the electrode within the flow channel. In particular, to lower the imposed voltage, one-dimensional (1D) Ag nanowires were modified on the microfoam electrode to build up a locally enhanced electric field and reduce cell damage. The self-powered electroporation system realized a successful delivery of small and large biomolecules into different cell lines with efficiency up to 86% and cell viability over 88%. The handle throughput achieved as high as 10⁵ cells min^-1 on continuously flowed cells. The high-throughput and self-powered electroporation system is expected to have potential applications in the fields of high-throughput drug and gene delivery for in vitro isolated cells.

Therapeutic Prospects of mRNA-Based Gene Therapy for Glioblastoma

The treatment of glioblastoma has been a big challenge for decades in the oncological field mainly owing to its unique biological characteristics, such as high heterogeneity, diffusing invasiveness, and capacity to resist conventional therapies. The mRNA-based therapeutic modality holds many superior features, including easy manipulation, rapid and transient expression, and adaptive convertibility without mutagenesis, which are suitable for dealing with glioblastoma's complexity and variability. Synthetic anticancer mRNAs carried by various vehicles act as the ultimate attackers of the tumor across biological barriers. In this modality, specifically targeted glioblastoma treatment can be guaranteed by adding targeting molecules at certain levels. The choice of mRNA-bearing vehicle and administration method is a fully patient-tailored selection. This review covers the advantages and possible limitations of mRNA-based gene therapy, the in vitro synthesis of mRNA, the feasible methods for synthetic mRNA delivery and clinical therapeutic prospects of mRNA-based gene therapy for glioblastoma.

Scalable Device for Automated Microbial Electroporation in a Digital Microfluidic Platform

Electrowetting-on-dielectric (EWD) digital microfluidic laboratory-on-a-chip platforms demonstrate excellent performance in automating labor-intensive protocols. When coupled with an on-chip electroporation capability, these systems hold promise for streamlining cumbersome processes such as multiplex automated genome engineering (MAGE). We integrated a single Ti:Au electroporation electrode into an otherwise standard parallel-plate EWD geometry to enable high-efficiency transformation of Escherichia coli with reporter plasmid DNA in a 200 nL droplet. Test devices exhibited robust operation with more than 10 transformation experiments performed per device without cross-contamination or failure. Despite intrinsic electric-field nonuniformity present in the EP/EWD device, the peak on-chip transformation efficiency was measured to be 8.6 ± 1.0 × 10⁸ cfu·μg^-1 for an average applied electric field strength of 2.25 ± 0.50 kV·mm^-1. Cell survival and transformation fractions at this electroporation pulse strength were found to be 1.5 ± 0.3 and 2.3 ± 0.1%, respectively. Our work expands the EWD toolkit to include on-chip microbial electroporation and opens the possibility of scaling advanced genome engineering methods, like MAGE, into the submicroliter regime.

At The Bedside: Clinical review of chimeric antigen receptor (CAR) T cell therapy for B cell malignancies

T cells kill microbial-infected and malignant cells by detection of nonself antigens with the TCR. Tumor reactivity can be encoded genetically by introducing a chimeric antigen receptor (CAR) into T cells. CARs are composed of an antigen-binding domain and an intracellular T cell activation domain. Early human trials evaluating CD19-targeted CAR T cells for chronic lymphocytic leukemia (CLL) showed limited responses until CARs included a costimulation domain, and conditioning chemotherapy was given before T cell infusion. Clinical trials evaluating CD19-targeted CAR T cells for B cell acute lymphoblastic leukemia (B-ALL) are demonstrating response rates up to 90%. However, these clinical outcomes are associated with a cytokine release syndrome (CRS), which is caused by T cell activation and manifests as high-grade fever, hypotension, and other cardiovascular complications. It is currently managed conservatively but can be treated with cytokine-directed therapy or with high-dose steroids. Current efforts are dedicated to confirming the clinical efficacy and managing toxicities in multicenter Phase II trials. We present a thorough overview of the preclinical and clinical development of CAR T cell therapy that will highlight important areas for the basic researcher to investigate in the laboratory and contribute to this exciting field.

All-in-one processing of heterogeneous human cell grafts for gene and cell therapy

Current cell processing technologies for gene and cell therapies are often slow, expensive, labor intensive and are compromised by high cell losses and poor selectivity thus limiting the efficacy and availability of clinical cell therapies. We employ cell-specific on-demand mechanical intracellular impact from laser pulse-activated plasmonic nanobubbles (PNB) to process heterogeneous human cell grafts ex vivo with dual simultaneous functionality, the high cell type specificity, efficacy and processing rate for transfection of target CD3+ cells and elimination of subsets of unwanted CD25+ cells. The developed bulk flow PNB system selectively processed human cells at a rate of up to 100 million cell/minute, providing simultaneous transfection of CD3+ cells with the therapeutic gene (FKBP12(V36)-p30Caspase9) with the efficacy of 77% and viability 95% (versus 12 and 60%, respectively, for standard electroporation) and elimination of CD25+ cells with 99% efficacy. PNB flow technology can unite and replace several methodologies in an all-in-one universal ex vivo simultaneous procedure to precisely and rapidly prepare a cell graft for therapy. PNB’s can process various cell systems including cord blood, stem cells, and bone marrow.

Large-Scale mRNA Transfection of Dendritic Cells by Electroporation in Continuous Flow Systems

Electroporation is well established for transient mRNA transfection of many mammalian cells, including immune cells such as dendritic cells used in cancer immunotherapy. Therapeutic application requires methods to efficiently electroporate and transfect millions of immune cells in a fast process with high cell survival. Continuous flow of suspended dendritic cells through a channel incorporating spatially separated microporous meshes with a synchronized electrical pulsing sequence can yield dendritic cell transfection rates of >75 % with survival rates of >90 %. This chapter describes the instrumentation and methods needed for the efficient transfection by electroporation of millions of dendritic cells in one continuous flow process.

Gene therapy for cancer: present status and future perspective

Advancements in human genomics over the last two decades have shown that cancer is mediated by somatic aberration in the host genome. This discovery has incited enthusiasm among cancer researchers; many now use therapeutic approaches in genetic manipulation to improve cancer regression and find a potential cure for the disease. Such gene therapy includes transferring genetic material into a host cell through viral (or bacterial) and non-viral vectors, immunomodulation of tumor cells or the host immune system, and manipulation of the tumor microenvironment, to reduce tumor vasculature or to increase tumor antigenicity for better recognition by the host immune system. Overall, modest success has been achieved with relatively minimal side effects. Previous approaches to cancer treatment, such as retrovirus integration into the host genome with the risk of mutagenesis and second malignancies, immunogenicity against the virus and/or tumor, and resistance to treatment with disease relapse, have markedly decreased with the new generation of viral and non-viral vectors. Several tumor-specific antibodies and genetically modified immune cells and vaccines have been developed, yet few are presently commercially available, while many others are still ongoing in clinical trials. It is anticipated that gene therapy will play an important role in future cancer therapy as part of a multimodality treatment, in combination with, or following other forms of cancer therapy, such as surgery, radiation and chemotherapy. The type and mode of gene therapy will be determined based on an individual's genomic constituents, as well as his or her tumor specifics, genetics, and host immune status, to design a multimodality treatment that is unique to each individual's specific needs.

Gene therapy for cancer: present status and future perspective

Advancements in human genomics over the last two decades have shown that cancer is mediated by somatic aberration in the host genome. This discovery has incited enthusiasm among cancer researchers; many now use therapeutic approaches in genetic manipulation to improve cancer regression and find a potential cure for the disease. Such gene therapy includes transferring genetic material into a host cell through viral (or bacterial) and non-viral vectors, immunomodulation of tumor cells or the host immune system, and manipulation of the tumor microenvironment, to reduce tumor vasculature or to increase tumor antigenicity for better recognition by the host immune system. Overall, modest success has been achieved with relatively minimal side effects. Previous approaches to cancer treatment, such as retrovirus integration into the host genome with the risk of mutagenesis and second malignancies, immunogenicity against the virus and/or tumor, and resistance to treatment with disease relapse, have markedly decreased with the new generation of viral and non-viral vectors. Several tumor-specific antibodies and genetically modified immune cells and vaccines have been developed, yet few are presently commercially available, while many others are still ongoing in clinical trials. It is anticipated that gene therapy will play an important role in future cancer therapy as part of a multimodality treatment, in combination with, or following other forms of cancer therapy, such as surgery, radiation and chemotherapy. The type and mode of gene therapy will be determined based on an individual's genomic constituents, as well as his or her tumor specifics, genetics, and host immune status, to design a multimodality treatment that is unique to each individual's specific needs.

Microfluidic electroporation for cellular analysis and delivery

Electroporation is a simple yet powerful technique for breaching the cell membrane barrier. The applications of electroporation can be generally divided into two categories: the release of intracellular proteins, nucleic acids and other metabolites for analysis and the delivery of exogenous reagents such as genes, drugs and nanoparticles with therapeutic purposes or for cellular manipulation. In this review, we go over the basic physics associated with cell electroporation and highlight recent technological advances on microfluidic platforms for conducting electroporation. Within the context of its working mechanism, we summarize the accumulated knowledge on how the parameters of electroporation affect its performance for various tasks. We discuss various strategies and designs for conducting electroporation at the microscale and then focus on analysis of intracellular contents and delivery of exogenous agents as two major applications of the technique. Finally, an outlook for future applications of microfluidic electroporation in increasingly diverse utilities is presented.

CARs in chronic lymphocytic leukemia -- ready to drive

Adoptive transfer of antigen-specific T cells has been adapted by investigators for treatment of chronic lymphocytic leukemia (CLL). To overcome issues of immune tolerance which limits the endogenous adaptive immune response to tumor-associated antigens (TAAs), robust systems for the genetic modification and characterization of T cells expressing chimeric antigen receptors (CARs) to redirect specificity have been produced. Refinements with regards to persistence and trafficking of the genetically modified T cells are underway to help improve potency. Clinical trials utilizing this technology demonstrate feasibility, and increasingly, these early-phase trials are demonstrating impressive anti-tumor effects, particularly for CLL patients, paving the way for multi-center trials to establish the efficacy of CAR(+) T cell therapy.

Cell engineering with synthetic messenger RNA

mRNA has become an important alternative to DNA as a tool for cell reprogramming. To be expressed, exogenous DNA must be transmitted through the cell cytoplasm and placed into the nucleus. In contrast, exogenous mRNA simply has to be delivered into the cytoplasm. This can result in a highly uniform transfection of the whole population of cells, an advantage that has not been observed with DNA transfer. The use of mRNA, instead of DNA, in medical applications increases protocol safety by abolishing the risk of transgene insertion into host genomes. In this chapter, we review the aspects of mRNA structure and function that are important for its "transgenic" behavior, such as the composition of mRNA molecules and complexes with RNA binding proteins, localization of mRNA in cytoplasmic compartments, translation, and the duration of mRNA expression. In immunotherapy, mRNA is employed in reprogramming of antigen presenting cells (vaccination) and cytolytic lymphocytes. Other applications include generation of induced pluripotent stem (iPS) cells, and genome engineering with modularly assembled nucleases. The most investigated applications of mRNA technology are also reviewed here.

Antibody-based therapeutics for the treatment of human B cell malignancies

The dynamic expression of various phenotypic markers during B cell development not only defines the particular stage in ontogeny but also provides the necessary growth, differentiation, maturation and survival signals. When a B cell at any given stage becomes cancerous, these cell surface molecules, intracellular signaling molecules, and the over-expressed gene products become favorite targets for potential therapeutic intervention. Various adaptive and adoptive immunotherapeutic approaches induce T cell and antibody responses against cancer cells, and successful remission leading to minimal residual disease has been obtained. Nonetheless, subsequent relapse and development of resistant clones prompted further development and several novel strategies are evolving. Engineered monoclonal antibodies with high affinity and specificity to target antigens have been developed and used either alone or in combination with chemotherapeutic drugs. They are also used as vehicles to deliver cytotoxic drugs, toxins, or radionuclides that are either directly conjugated or encapsulated in liposomal vesicles. Likewise, genetically engineered T cells bearing chimeric antigen receptors are used to redirect cytotoxicity to antigen-positive target cells. This review describes recent advancements in some of these adoptive immunotherapeutic strategies targeting B cell malignancies.

Nonviral RNA transfection to transiently modify T cells with chimeric antigen receptors for adoptive therapy

Redirecting T cells with a chimeric antigen receptor (CAR) of predefined specificity showed remarkable efficacy in the adoptive therapy trials of malignant diseases. The CAR consists of a single chain fragment of variable region (scFv) antibody targeting domain covalently linked to the CD3ζ signalling domain of the T cell receptor complex to mediate T cell activation upon antigen engagement. By using an antibody-derived targeting domain a CAR can potentially redirect T cells towards any target expressed on the cell surface as long as a binding domain is available. Antibody-mediated targeting moreover circumvents MHC restriction of the targeted antigen, thereby broadening the potential of applicability of adoptive T cell therapy. While T cells were so far genetically modified by viral transduction, transient modification with a CAR by RNA transfection gained increasing interest during the last years. This chapter focuses on methods to modify human T cells from peripheral blood with a CAR by electroporation of in vitro transcribed RNA and to test modified T cells for function for use in adoptive immunotherapy.

Cell-specific multifunctional processing of heterogeneous cell systems in a single laser pulse treatment

Current methods of cell processing for gene and cell therapies use several separate procedures for gene transfer and cell separation or elimination, because no current technology can offer simultaneous multifunctional processing of specific cell subsets in highly heterogeneous cell systems. Using the cell-specific generation of plasmonic nanobubbles of different sizes around cell-targeted gold nanoshells and nanospheres, we achieved simultaneous multifunctional cell-specific processing in a rapid single 70 ps laser pulse bulk treatment of heterogeneous cell suspension. This method supported the detection of cells, delivery of external molecular cargo to one type of cells and the concomitant destruction of another type of cells without damaging other cells in suspension, and real-time guidance of the above two cellular effects.

Cell-specific transmembrane injection of molecular cargo with gold nanoparticle-generated transient plasmonic nanobubbles

Optimal cell therapies require efficient, selective and rapid delivery of molecular cargo into target cells without compromising their viability. Achieving these goals ex vivo in bulk heterogeneous multi-cell systems such as human grafts is impeded by low selectivity and speed of cargo delivery and by significant damage to target and non-target cells. We have developed a cell level approach for selective and guided transmembrane injection of extracellular cargo into specific target cells using transient plasmonic nanobubbles (PNB) as cell-specific nano-injectors. As a technical platform for this method we developed a laser flow cell processing system. The PNB injection method and flow system were tested in heterogeneous cell suspensions of target and non-target cells for delivery of Dextran-FITC dye into squamous cell carcinoma HN31 cells and transfection of human T-cells with a green fluorescent protein-encoding plasmid. In both models the method demonstrated single cell type selectivity, high efficacy of delivery (96% both for HN31 cells T-cells), speed of delivery (nanoseconds) and viability of treated target cells (96% for HN31 cells and 75% for T-cells). The PNB injection method may therefore be beneficial for real time processing of human grafts without removal of physiologically important cells.

Chimeric antibody receptors (CARs): driving T-cell specificity to enhance anti-tumor immunity

Adoptive transfer of antigen-specific T cells is a compelling tool to treat cancer. To overcome issues of immune tolerance which limits the endogenous adaptive immune response to tumor-associated antigens, robust systems for the genetic modification and characterization of T cells expressing chimeric antigen receptors (CARs) to redirect specificity have been produced. Refinements with regards to persistence and trafficking of the genetically modified T cells are underway to help improve the potency of genetically modified T cells. Clinical trials utilizing this technology demonstrate feasibility, and increasingly, antitumor activity, paving the way for multi-center trials to establish the efficacy of this novel T-cell therapy.

Redirecting T-cell specificity by introducing a tumor-specific chimeric antigen receptor

Infusions of antigen-specific T cells have yielded therapeutic responses in patients with pathogens and tumors. To broaden the clinical application of adoptive immunotherapy against malignancies, investigators have developed robust systems for the genetic modification and characterization of T cells expressing introduced chimeric antigen receptors (CARs) to redirect specificity. Human trials are under way in patients with aggressive malignancies to test the hypothesis that manipulating the recipient and reprogramming T cells before adoptive transfer may improve their therapeutic effect. These examples of personalized medicine infuse T cells designed to meet patients' needs by redirecting their specificity to target molecular determinants on the underlying malignancy. The generation of clinical grade CAR(+) T cells is an example of bench-to-bedside translational science that has been accomplished using investigator-initiated trials operating largely without industry support. The next-generation trials will deliver designer T cells with improved homing, CAR-mediated signaling, and replicative potential, as investigators move from the bedside to the bench and back again.