T-cell receptor gene transfer by lentiviral vectors in adoptive cell therapy

Current Landscape of Various Techniques and Methods of Gene Therapy through CRISPR Cas9 along with its Pharmacological and Interventional Therapies in the Treatment of Type 2 Diabetes Mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is frequently referred to as a "lifestyle illness". In 2000, India (31.7 million) had the greatest global prevalence of diabetes mellitus, followed by China (20.8 million), the United States (17.7 million), and other countries. In recent years, the treatment of gene therapy (T2DM) has attracted intensive interest.

OBJECTIVE

We aimed to critically review the literature on the various techniques and methods, which may be a possible novel approach through the gene therapy CRISPR Cas9 and some other gene editing techniques for T2DM. Interventional and pharmacological approaches for the treatment of T2DM were also included to identify novel therapies for its treatment.

METHOD

An extensive literature survey was done on databases like PubMed, Elsevier, Science Direct and Springer.

CONCLUSION

It can be concluded from the study that recent advancements in gene-editing technologies, such as CRISPR Cas9, have opened new avenues for the development of novel therapeutic approaches for T2DM. CRISPR Cas9 is a powerful tool that enables precise and targeted modifications of the genome.

Potential roles of hyaluronic acid in in vivo CAR T cell reprogramming for cancer immunotherapy

Chimeric antigen receptor (CAR) T cell therapy has recently shown unprecedented clinical efficacy for cancer treatment, particularly of hematological malignancies. However, the complex manufacturing processes that involve ex vivo genetic modification of autologous T cells limits its therapeutic application. CAR T cells generated in vivo provide a valid alternative immunotherapy, "off-the-shelf", for cancer treatment. This approach requires carriers for the delivery of CAR-encoding constructs, which are plasmid DNA or messenger RNA, to T cells for CAR expression to help eradicate the tumor. As such, there are a growing number of studies reporting gene delivery systems for in vivo CAR T cell therapy based on viral vectors and polymeric nanoparticles. Hyaluronic acid (HA) is a natural biopolymer that can serve for gene delivery, because of its inherent properties of cell recognition and internalization, as well as its biodegradability, biocompatibility, and presence of functional groups for the chemical conjugation of targeting ligands. In this review, the potential of HA in the delivery of CAR constructs is discussed on the basis of previous experience of HA-based nanoparticles for gene therapy. Furthermore, current studies on CAR carriers for in vivo-generated CAR T cells are included, giving an idea of a rational design of HA-based systems for the more efficient delivery of CAR to circulating T cells.

Fasten the seat belt: Increasing safety of CAR T-cell therapy

After the recent success and approvals of chimeric antigen receptor (CAR) T cells in haematological malignancies, its efficacy is currently evaluated in a broad spectrum of tumor entities including melanoma. However, severe and potentially life-threatening side effects like cytokine release syndrome, neurologic toxicities, and the competing risk of morbidity and mortality from the treatment itself are still a major limiting factor in the current CAR T-cell landscape. In addition, especially in solid tumors, the lack of ideal target antigens to avoid on-target/off-tumor toxicities also restricts its use. While various groups are working on strategies to boost CAR T-cell efficacy, mechanisms to increase engineered T-cell safety should not move out of focus. Thus, the aim of this article is to summarize and to discuss current and potential future strategies and mechanisms to increase CAR T-cell safety in order to enable the wide use of this promising approach in melanoma and other tumor entities.

TCRγ4δ1-engineered αβT cells exhibit effective antitumor activity

T cell engineering with T cell receptors (TCRs) specific for tumors plays an important role in adoptive T-cell transfer (ATC) therapy for cancer. Here, we present a novel strategy to redirect peripheral blood-derived αβT cells against tumors via TCRγ4δ1 gene transduction. The broad-spectrum anti-tumor activity of TCRδ1 cells in innate immunity is dependent on CDR3δ1. TCRγ4δ1-engineered αβT cells were prepared by lentiviral transduction and characterized by analyzing in vitro and in vivo cytotoxicity to tumors, ability of proliferation and cytokine production, and their potential role in autoimmunity. Results show TCRγ4δ1 genes were transduced to approximately 36% of polyclonal αβT cells. TCRγ4δ1-engineered αβT cells exhibited an effective in-vitro TCRγδ-dependent cytotoxicity against various tumor cells via the perforin-granzyme pathway. They also showed a strong proliferative capacity and robust cytokine production. TCRγ4δ1-engineered αβT cells neither expressed mixed TCR dimers nor bound/killed normal cells in vitro. More importantly, adoptive transfer of TCRγ4δ1-engineered αβT cells into nude mice bearing a human HepG2 cell line significantly suppressed tumor growth. Our results demonstrate a novel role for TCRγ4δ1 in gene therapy and ATC for cancer.

Adoptive T-cell therapy in the treatment of viral and opportunistic fungal infections

Viral infections and opportunistic fungal pathogens represent a major menace for immunocompromised patients. Despite the availability of antifungal and antiviral drugs, mortality in these patients remains high, underlining the need of novel therapeutic options based on completely different strategies. This review describes the potential of several T-cell-based therapeutic approaches in the prophylaxis and treatment of infectious diseases with a particular focus on persistent viral infections and opportunistic fungal infections, as these mostly affect immunocompromised patients.

Lentiviral vectors for cancer immunotherapy and clinical applications

The success of immunotherapy against infectious diseases has shown us the powerful potential that such a treatment offers, and substantial work has been done to apply this strategy in the fight against cancer. Cancer is however a fiercer opponent than pathogen-caused diseases due to natural tolerance towards tumour associated antigens and tumour-induced immunosuppression. Recent gene therapy clinical trials with viral vectors have shown clinical efficacy in the correction of genetic diseases, HIV and cancer. The first successful gene therapy clinical trials were carried out with onco(γ-)retroviral vectors but oncogenesis by insertional mutagenesis appeared as a serious complication. Lentiviral vectors have emerged as a potentially safer strategy, and recently the first clinical trial of patients with advanced leukemia using lentiviral vectors has proven successful. Additionally, therapeutic lentivectors have shown clinical efficacy for the treatment of HIV, X-linked adrenoleukodystrophy, and β-thalassaemia. This review aims at describing lentivectors and how they can be utilized to boost anti-tumour immune responses by manipulating the effector immune cells.

Influenza virus-specific TCR-transduced T cells as a model for adoptive immunotherapy

Adoptive transfer of T lymphocytes equipped with tumor-antigen specific T-cell receptors (TCRs) represents a promising strategy in cancer immunotherapy, but the approach remains technically demanding. Using influenza virus (Flu)-specific T-cell responses as a model system we compared different methods for the generation of T-cell clones and isolation of antigen-specific TCRs. Altogether, we generated 12 CD8(+) T-cell clones reacting to the Flu matrix protein (Flu-M) and 6 CD4(+) T-cell clones reacting to the Flu nucleoprotein (Flu-NP) from 4 healthy donors. IFN-γ-secretion-based enrichment of antigen-specific cells, optionally combined with tetramer staining, was the most efficient way for generating T-cell clones. In contrast, the commonly used limiting dilution approach was least efficient. TCR genes were isolated from T-cell clones and cloned into both a previously used gammaretroviral LTR-vector, MP91 and the novel lentiviral self-inactivating vector LeGO-MP that contains MP91-derived promotor and regulatory elements. To directly compare their functional efficiencies, we in parallel transduced T-cell lines and primary T cells with the two vectors encoding identical TCRs. Transduction efficiencies were approximately twice higher with the gammaretroviral vector. Secretion of high amounts of IFN-γ, IL-2 and TNF-α by transduced cells after exposure to the respective influenza target epitope proved efficient specificity transfer of the isolated TCRs to primary T-cells for both vectors, at the same time indicating superior functionality of MP91-transduced cells. In conclusion, we have developed optimized strategies to obtain and transfer antigen-specific TCRs as well as designed a novel lentiviral vector for TCR-gene transfer. Our data may help to improve adoptive T-cell therapies.

Enhanced T cell receptor gene therapy for cancer

IMPORTANCE OF THE FIELD

Adoptive therapy with T cell receptor- (TCR-) redirected T cells has shown efficacy in mouse tumor models and first responses in cancer patients. One prerequisite to elicit effective anti-tumor reactivity is the transfer of high-avidity T cells. Their generation, however, faces several technical difficulties. Target antigens are often expressed at low levels and their recognition requires the use of high-affine receptors. Yet, mainly low-affinity TCRs have been isolated from tumor-infiltrating lymphocytes. Furthermore, upon transfer into a T cell the introduced receptor has to compete with the endogenous TCR.

AREAS COVERED IN THIS REVIEW

This review discusses how the functional avidity of TCR-modified T cells can be enhanced by i) increasing the amount of introduced TCR heterodimers on the cell surface; and ii) generating receptors with high affinity. Risks of TCR gene therapy and possible safety mechanisms are discussed.

WHAT THE READER WILL GAIN

The reader will gain an overview of the technical developments in TCR and T cell engineering.

TAKE HOME MESSAGE

Despite technical obstacles, many advances have been made in the generation of high-avidity T cells expressing enhanced TCRs. Mouse studies and clinical trials will evaluate the effect of these improvements.

Gene therapy in diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease, whereby auto-reactive cytotoxic T cells target and destroy insulin-secreting β-cells in pancreatic islets leading to insulin deficiency and subsequent hyperglycemia. These individuals require multiple daily insulin injections every day of their life without which they will develop life-threatening diabetic ketoacidosis (DKA) and die. Gene therapy by viral vector and non-viral transduction may be useful techniques to treat T1D as it can be applied from many different angles; such as the suppression of autoreactive T cells to prevent islet destruction (prophylactic) or the replacement of the insulin gene (post-disease). The need for a better method for providing euglycemia arose from insufficient numbers of cadaver islets for transplantation and the immunosuppression required post-transplant. Ectopic expression of insulin or islet modification have been examined, but not perfected. This review examines the various gene transfer methods, gene therapy techniques used to date and promising novel techniques for the maintenance of euglycemia in the treatment of T1D.

Recombinant lentivector as a genetic immunization vehicle for antitumor immunity

Encouraged by remarkable successes in preventing infectious diseases and by the well-established potential of the immune system for controlling tumor growth, active therapeutic immunization approaches hold great promise for treating malignant tumors. In recent years, engineered recombinant viral vectors have been carefully examined as genetic-immunization vehicles and have been demonstrated to induce potent T-cell-mediated immune responses that can control tumor growth. Very recent efforts suggest that lentivectors possess important advantages over other candidate recombinant viral vectors for genetic immunization. Here, we review the development of recombinant lentivectors and the characteristics of T-cell immune responses elicited by lentivector immunization, including the mechanism of T-cell priming with a focus on the role of skin dendritic cells and potential applications for tumor immunotherapy.