Adoptive T-Cell Therapy of Cancer

Cancer Nano-Immunotherapy: The Novel and Promising Weapon to Fight Cancer

Cancer is a complex disease that, despite advances in treatment and the greater understanding of the tumor biology until today, continues to be a prevalent and lethal disease. Chemotherapy, radiotherapy, and surgery are the conventional treatments, which have increased the survival for cancer patients. However, the complexity of this disease together with the persistent problems due to tumor progression and recurrence, drug resistance, or side effects of therapy make it necessary to explore new strategies that address the challenges to obtain a positive response. One important point is that tumor cells can interact with the microenvironment, promoting proliferation, dissemination, and immune evasion. Therefore, immunotherapy has emerged as a novel therapy based on the modulation of the immune system for combating cancer, as reflected in the promising results both in preclinical studies and clinical trials obtained. In order to enhance the immune response, the combination of immunotherapy with nanoparticles has been conducted, improving the access of immune cells to the tumor, antigen presentation, as well as the induction of persistent immune responses. Therefore, nanomedicine holds an enormous potential to enhance the efficacy of cancer immunotherapy. Here, we review the most recent advances in specific molecular and cellular immunotherapy and in nano-immunotherapy against cancer in the light of the latest published preclinical studies and clinical trials.

Cancer immunotherapy: Challenges and limitations

Although cancer immunotherapy has taken center stage in mainstream oncology inducing complete and long-lasting tumor regression, only a subset of patients receiving treatment respond and others relapse after an initial response. Different tumor types respond differently, and even in cancer types that respond (hot tumors), we still observe tumors that are unresponsive (cold tumors), suggesting the presence of resistance. Hence, the development of intrinsic or acquired resistance is a big challenge for the cancer immunotherapy field. Resistance to immunotherapy, including checkpoint inhibitors, CAR-T cell therapy, oncolytic viruses, and recombinant cytokines arises due to cancer cells employing several mechanisms to evade immunosurveillance.

Adoptive Immunotherapy For Leukemia With Ex vivo Expanded T Cells

The development of novel T cell therapies to target leukemia has facilitated the translation of this approach for hematologic malignancies. Different methods of manufacturing leukemia-specific T cells have evolved, along with additional measures to increase the safety of this therapy. This is an overview of expanded T cell therapeutics with a focus on how the manufacturing strategies have been refined, and where the research is heading.

High-intensity focused ultrasound tumor ablation activates autologous tumor-specific cytotoxic T lymphocytes

Previous studies have shown that high-intensity focused ultrasound (HIFU) ablation can enhance host antitumor immune response, though the mechanism is still unknown. In the present study, we investigated whether HIFU ablation could activate tumor-specific T lymphocytes and then induce antitumor cellular immunity. We studied 70 C57BL/6J mice bearing the H(22) tumor; they were randomly divided into a HIFU group and a sham-HIFU group. Of the mice, 35 in the HIFU group underwent HIFU ablation of the H(22) hepatic tumor, and the remaining 35 received a sham-HIFU procedure. In addition, 35 female, naïve syngeneic C57BL/6J mice were used as controls. All mice were sacrificed 14 days after HIFU, and the spleens were harvested. The function of T lymphocytes was determined. As a valuable tool for detecting and characterizing peptide-specific cells, the frequency of MHC class I tetramer/CD8-positive cells was quantified, which could help to determine the response and number of T lymphocytes. The therapeutic effect of the HIFU-activated lymphocytes on tumor-bearing mice was investigated after adoptive transfer of the lymphocytes. The results showed that compared to sham-HIFU and control groups, HIFU ablation significantly increased the cytotoxicity of cytotoxic T lymphocytes (p < 0.05), with a significant increase of IFN-γ and TNF-α secretion (p < 0.001). The frequency of the MHC class I tetramer/CD8-positive cells was significantly higher in the HIFU group (p < 0.05). A stronger inhibition of tumor progression and higher survival rates were observed to be significant after adoptive immunotherapy in the HIFU group as compared to the sham-HIFU and control groups (p < 0.01). It is concluded that HIFU ablation could activate tumor-specific T lymphocytes, thus inducing antitumor cellular immune responses in tumor-bearing mice.

The construction of chimeric T-Cell receptor with spacer base of modeling study of VHH and MUC1 interaction

Adaptive cell immunotherapy with the use of chimeric receptors leads to the best and most specific response against tumors. Chimeric receptors consist of a signaling fragment, extracellular spacer, costimulating domain, and an antibody. Antibodies cause immunogenicity; therefore, VHH is a good replacement for ScFv in chimeric receptors. Since peptide sequences have an influence on chimeric receptors, the effect of peptide domains on each other's conformation were investigated. CD3Zeta, CD28, VHH and CD8α, and FcgIIα are used as signaling moieties, costimulating domain, antibody, and spacers, respectively. To investigate the influence of the ligation of spacers on the conformational structure of VHH, models of VHH were constructed. Molecular dynamics simulation was run to study the influence of the presence of spacers on the conformational changes in the binding sites of VHH. Root mean square deviation and root mean square fluctuation of critical segments in the binding site showed no noticeable differences with those in the native VHH. Results from molecular docking revealed that the presence of spacer FcgIIα causes an increasing effect on VHH with MUC1 interaction. Each of the constructs was transformed into the Jurkat E6.1. Expression analysis and evaluation of their functions were examined. The results showed good expression and function.

Adoptive therapy using antigen-specific T-cell clones

T-cell therapy involves the ex vivo isolation and expansion of antigen-specific T cells for adoptive transfer. The use of T-cell clones represents one embodiment of this approach and provides a uniform population of effector cells, so that parameters contributing to an effective response can be rigorously evaluated. T cells of defined specificity, phenotype, and function are isolated and expanded; when infused into patients, these intrinsic factors can be considered in light of extrinsic factors such as the type of conditioning regimen, cytokine support, and immunomodulatory reagents. In this chapter, 2 topics related to the use of antigen-specific T-cell clones are discussed: first, advances enabling the isolation and expansion of antigen-specific T-cell clones for human trials of adoptive therapy, and second, a contextual framework of advantages and limitations in which the use of adoptively transferred T-cell clones can be judiciously applied as a means to dissect the requirements for effective therapy.

Virus-specific cytotoxic CD4+ T cells for the treatment of EBV-related tumors

Although adoptive immunotherapy with CD8(+) CTL is providing clinically relevant results against EBV-driven malignancies, the effector role of CD4(+) T cells has been poorly investigated. We addressed this issue in a lymphoblastoid cell line-induced mouse model of posttransplant lymphoproliferative disease (PTLD) by comparing the therapeutic efficacy of EBV-specific CD4(+) and CD8(+) T cell lines upon adoptive transfer. CD4(+) T cells disclosed a long-lasting and stronger proliferative potential than CD8(+) T cells, had a similar activation and differentiation marker profile, efficiently killed their targets in a MHC class II-restricted manner, and displayed a lytic machinery comparable to that of cognate CD8(+) T cells. A detailed analysis of Ag specificity revealed that CD4(+) T cells potentially target EBV early lytic cycle proteins. Nonetheless, when assessed for the relative therapeutic impact after in vivo transfer, CD4(+) T cells showed a reduced activity compared with the CD8(+) CTL counterpart. This feature was apparently due to a strong and selective downmodulation of MHC class II expression on the tumor cells surface, a phenomenon that could be reverted by the demethylating agent 5-aza-2'-deoxycytidine, thus leading to restoration of lymphoblastoid cell line recognition and killing by CD4(+) T cells, as well as to a more pronounced therapeutic activity. Conversely, immunohistochemical analysis disclosed that HLA-II expression is fully retained in human PTLD samples. Our data indicate that EBV-specific cytotoxic CD4(+) T cells are therapeutic in mice bearing PTLD-like tumors, even in the absence of CD8(+) T cells. These findings pave the way to use cultures of pure CD4(+) T cells in immunotherapeutic approaches for EBV-related malignancies.

Adoptive CD8 T cell control of pathogens cannot be improved by combining protective epitope specificities

Adoptive transfer of CD8 T cells has the potential to cure infectious or malignant diseases that are refractory to conventional chemotherapy. A practically important but still unanswered question is whether mixtures of protective CD8 T cells with different epitope specificities mediate more efficient effector cell functions than do the monospecific individual CD8 T cell populations. In this study, we have addressed this issue for models of viral and bacterial infection. CD8 T cell-mediated cytotoxicity in vitro and protection in vivo were assessed to test whether CD8 T cell lines cooperate in target cell lysis and control of infection, respectively. Our data clearly show that mixtures of cytolytic T cell lines specific for different epitopes of either murine cytomegalovirus or Listeria monocytogenes do not act synergistically. An efficient anti-infectious protection thus proved to be dependent primarily on the number of transferred protective CD8 T cells rather than on the cooperative effects of multiple specificities.

Gene-modified bone marrow cell therapy for prostate cancer

There is a critical need to develop new and effective cancer therapies that target bone, the primary metastatic site for prostate cancer and other malignancies. Among the various therapeutic approaches being considered for this application, gene-modified cell-based therapies may have specific advantages. Gene-modified cell therapy uses gene transfer and cell-based technologies in a complementary fashion to chaperone appropriate gene expression cassettes to active sites of tumor growth. In this paper, we briefly review potential cell vehicles for this approach and discuss relevant gene therapy strategies for prostate cancer. We further discuss selected studies that led to the conceptual development and preclinical testing of IL-12 gene-modified bone marrow cell therapy for prostate cancer. Finally, we discuss future directions in the development of gene-modified cell therapy for metastatic prostate cancer, including the need to identify and test novel therapeutic genes such as GLIPR1.

IL-21 mediated Foxp3 suppression leads to enhanced generation of antigen-specific CD8+ cytotoxic T lymphocytes

Efforts to reproducibly isolate tumor antigen-specific T cells from patients would be facilitated by removing immunoregulatory barriers. Using a human model for eliciting T-cell responses to tumor-associated antigens, we develop a novel strategy that eliminates nearly all Foxp3-expressing cells through the combination of CD25 depletion and IL-21 treatment resulting in a more than 150-fold decrease in Foxp3(+) cells to virtually undetectable levels and a more than 200-fold increase in antigen-specific cytotoxic T lymphocytes (CTLs). The extent of Foxp3 elimination and degree of expansion of antigen-specific CTLs shown in this study have not previously been achievable and are unique to IL-21. We demonstrate for the first time a possible mechanism for IL-21-mediated expansion of antigen-specific CTLs that involves suppression of Foxp3-expressing cells and reversal of inhibition to tumor-associated antigen-specific CTL generation in vitro. Taken together, the combination of CD25 depletion and IL-21 exposure, by releasing regulatory constraints, leads to markedly enhanced CTL induction and represents a robust strategy for the ex vivo generation of antigen-specific T cells for adoptive cellular therapy.