Glioblastoma is a deadly brain cancer with discouraging standard of care. New methods like convection enhanced delivery and chimeric antigen receptor T cells (CAR-T) are promising treatments that can be translated to glioblastoma. In this study, CAR-T cell flow through a hydrogel was explored in the context of in-vitro convection enhanced delivery. A culture method to create large spheroids mimicking tumors from preexisting glioblastoma stem cell lines was fabricated, a convection enhanced delivery system for in-vitro testing was designed, and characterization of the CAR-T cells using the in-vitro system took place. The spheroid culture method was successfully optimized to produce spheroids large enough to act as a sufficient tumor in little time, the in-vitro set-up successfully administered treatment, and CAR-T cells were found to increase their velocities through a medium as their injection velocity increased. It was discovered that the density of the spheroid plays a crucial role in treatment delivery, often times driving how treatment will move through the spheroid. This system can be used in the future studies to test the killing potential of CAR-T cells to a tumor in-vitro. / Master of Science / Glioblastoma is a deadly brain cancer with current treatments that are discouraging at best. New methods must be utilized to aid in patient recovery. Chimeric antigen receptor T-Cells (CAR-T) are a promising treatment that can be used in glioblastoma. In this study, CAR-T cell behavior is defined in the context of in-vitro convection enhanced delivery. A large spheroid, or sphere of cells, mimicking a tumor was created, a convection enhanced delivery system set-up for in-vitro testing was designed, and characterization of CAR-T cell behavior using the in-vitro system took place. The spheroids were successfully cultured to act as a sufficient tumor, the in-vitro set-up successfully administered treatment, and CAR-T cells were found to increase their velocities in a gel as their injection velocity increases. It was discovered that the density of the spheroid plays a crucial role in treatment delivery, often times driving how treatment will move through the spheroid. This system can be used in the future studies to test the killing potential of CAR-T cells to a tumor in-vitro.

Advances in our understanding of the molecular events leading to cancer have facilitated the development of next-generation targeted therapies. Among the most promising new approaches is immuno-oncology, where therapeutic agents engage the immune system to fight cancer. One exciting strategy therein is the adoptive transfer of ex vivo cultivated tumor-specific T lymphocytes into a cancer patient. Tumor-specific T cells can be produced by engineering a patient’s own T cells with synthetic receptors (e.g. chimeric antigen receptors (CARs)) designed to redirect T cell cytotoxicity against a tumor target. CAR-engineered T cells (CAR-T cells) were expected to be a non-toxic cellular therapy which would seek out and specifically eliminate disseminated tumors. The clinical experience supports the promise of CAR-T cell therapy (striking efficacy has been observed in the treatment of hematological malignancies), while highlighting areas for improvement; CAR-T cell use has been associated with a host of toxicities and robust clinical efficacy has yet to be replicated in solid tumors. This thesis uses pre-clinical models to describe previously unappreciated aspects of CAR-T cell-associated toxicity and novel synthetic receptor strategies, including: i. The capacity of NKG2D-based CAR-T cells to mediate toxicity. ii. The utility of designed ankyrin repeat proteins as CAR antigen-binding domains. iii. The discovery that variables intrinsic to human CAR-T cell products contribute to toxicity. iv. A novel synthetic receptor capable of redirecting T cell specificity against a tumor target – the T cell antigen coupler (TAC). Unlike equivalent CAR-T cells, TAC-T cells are capable of mediating efficacy against a solid tumor in the absence of toxicity. We anticipate that these results will contribute towards the development of next-generation synthetic receptor-engineered T cell products that can deliver upon the promise of safe, systemic cancer therapeutics. / Thesis / Doctor of Philosophy (PhD) / The human immune system has the unique capacity to “seek and destroy” tumor cells throughout the body. A novel class of drugs, immuno-oncology agents, harness this ability to fight cancer. Within this class is a new cellular drug where genetic engineering is used to create killer immune cells (called T cells) capable of recognizing and eliminating tumors. Two of these cellular drugs have recently received FDA approval, supporting the feasibility of this approach. However, further research is needed to improve the safety of engineered-T cells and increase the number of patients whom can benefit from their use. This thesis uses laboratory investigations to better understand the side-effects associated with anti-cancer engineered-T cells and evaluate new engineering strategies. We anticipate that these results will contribute towards the development of next-generation engineered-T cell drugs which retain the ability to function systemically against cancer but offer an enhanced safety profile.

Breast cancer is one of the most common cancer types in women and its metastases cause most patient deaths in the advanced stage of this disease. 1,2,3 Unfortunately, metastases develop drug resistance to chemotherapy and impaired T lymphocyte infiltration into metastatic lesions by compressing blood vessels. 4,5,10,11,12 Although losartan decompressed vessels and increased the presence of T lymphocytes in the metastatic lesions, T-cells were not effective at eliminating tumors.10 In this thesis, we generated chimeric antigen receptor constructs that have specificity against epithelial cell adhesion molecule (EpCAM). After optimizing a retroviral transfection/transduction system, we successfully generated EpCAM CAR T-cells and tested their efficacy against tumor spheroids. We noticed a dramatic reduction of spheroids' area and spheroids' diameter after 36 hours of treatment and observed spheroids’ destruction and tumor cell elimination after 96 hours of treatment, compared to non-specific stimulated T-cells treatment on tumor spheroids. EpCAM CAR T-cells have been shown to be effective against cancer in vitro; therefore, injection of EpCAM CAR T-cells into mice with breast cancer will be conducted to determine whether losartan is able to improve infiltration. We expect that the use of losartan will improve the number of infiltrated CAR-T-cells and their efficacy against breast tumors.

Liver metastases are the most common cause of death in colorectal cancer patients. The standard of care and potential for cure for colorectal liver metastases is resection, but often times disease it too extensive for this treatment. Over the years, cancer research has made way for advances in treating progressive disease through immunotherapy. By genetically modifying an individual’s immune system using virally transduced chimeric antigen receptor T cells (CAR-T), patients are better able to receive exquisitely specific T cells to target specific tumors. Furthermore, selective delivery strategies may enhance efficacy while limiting detrimental, systemic adverse effects. Not only this, CAR-Ts have also lead to complete remission in some liquid tumors while maintaining the potential for remission in solid tumors as well. This literature review takes readers through the emergence of the different generations of CAR-T and the various studies including clinical trials that have demonstrated the safety and efficacy of CAR-T. The second portion of this paper will outline the design for a phase II clinical trial using intrahepatic CAR-T therapy in addition to selective internal radiation therapy (SIRT) for refractory CEA+ colorectal liver metastases. Benefits and limitations of using these therapies are further discussed.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22882号 / 医博第4676号 / 新制||医||1047(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙折 晃史, 教授 濵﨑 洋子, 教授 羽賀 博典 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Most Adoptive Cell Therapies (ACT), including CAR T cell therapies, suffer failure because of the severe side effects due to loss-of-control of the therapeutic cells once they are inside the patient’s body, suggesting that novel strategies must be developed for a better in vivo control of these engineered cells. In the meantime, CAR T cell therapies targeting solid tumors have not experienced the remarkable success achieved with hematopoietic cancers, mainly due to continuous tumor antigen exposure and a suppressive tumor microenvironment. Here we designed a private passageway fusion receptor, which is composed of a ligand binding domain and a glycosylphosphatidylinositol (GPI) anchoring domain, to be expressed and localized to the surface of CAR T cells independently to the classical CAR T construct. These ligand binding domains preserve high binding affinity towards their cognate ligands and are only expressed on the CAR T cells that have been transduced. Therefore, cytotoxic drugs or immunosuppressants linked to the corresponding targeting ligands are shown to be specifically delivered to these fusion receptor positive CAR T cells for lowering the activity of the over-activated CAR T cells. On the other hand, we discovered that a potent TLR7 agonist is able to enhance the lysis effect of the exhausted CAR T cells in a co-culture model. Serial releasable and non-releasable targeted TLR7 agonists were prepared and tested. Based on these data, we suggest that our secret passageway fusion receptor platform provides a better control of the activity of CAR T cells using the corresponding targeting ligand-payload conjugates in a dose dependent manner and function as a doorway for the delivery of instructions to CAR T cells for versatile purposes.

This thesis addresses multiple approaches to investigating mechanisms of immune linked disease. There are four projects outlined below which describe the work of these investigations. First, educating students about techniques to study disease and therapies is an important area of research. Flow cytometry is a common technique in immunology and its versatility and high throughput abilities can be applied to many fields. While it is very useful, flow cytometry is a complex technique that requires training to operate and understand, and there are very few reports about administering effective training. This thesis outlines the first report of a full semester university course about flow cytometry. Students who completed the course reported increased confidence in their skill levels in conceptual, technical and analytical areas. Second, in the fight against cancer, immunotherapies may provide the necessary adaptability to successfully combat many cancer types. By strengthening and educating the immune system, clinicians can help patients fight cancer without resorting to harmful chemotherapeutics, or immunotherapies can be used in tandem with current treatments. Chimeric antigen receptor (CAR) T cells and checkpoint blockade are two of the most successful immunotherapies. CAR T cells combine the extraordinary binding ability of an antibody with T cell signaling molecules via genetic engineering, for a faster and more efficient cancer killing version of the patient's own T cells. These have been remarkably successful, but results depend on the specific signaling co-receptors that are included in the design. Increased understanding of co-receptor function could help in making CAR T cell design more specific, and enable CAR T cells to be effective against more types of cancers. Metabolic function is crucial in understanding T cell therapeutics because T cells need to use energy efficiently enough to compete with ravenous cancer cells. This thesis outlines an ongoing investigation into a co-receptor's effect on CAR T cell metabolism, suggesting that co-receptors can alter CAR T cell metabolism by increasing maximal respiration. Third, CD5 is a negative regulatory co-receptor on T cells that can modulate T cell activation. Related inhibitory co-receptors (PD-1 and CTLA-4) are currently being effectively blocked as checkpoint therapies to reactivate T cells towards cancerous cells. This thesis outlines ongoing work investigating CD5's impact on cellular metabolism. We have found that T cells without CD5 are hypermetabolic as compared to normal naïve T cells. CD5 deficient T cells also have higher maximal respiration, higher basal respiration and higher glycolytic capacity. These differences are also present transiently after non-specific activation. Thus, CD5 significantly regulates the ability of a T cell to use energy, suggesting that CD5 may be a good target for creating more efficient T cell immunotherapies. Fourth, in a separate project, this thesis examines environmental causes of disease. Asthma and allergies are common and growing problems in children and adults. Evaporative cooling can be a less expensive alternative to central cooling, but its effects on allergens and other bioaerosols in the home remains unclear. This project examines the relationship between evaporative cooling and bioaerosols (dust mites, bacterial endotoxin, and fungal β-(1→3)-D-glucans) in low income homes in Utah. We report significantly higher levels of these bioaerosols, particularly fungi in homes with evaporative cooling after adjusting for home-specific factors.

Rapid developments in the field of CAR T cells offer important new opportunities while at the same time increasing numbers of patients pose major challenges. This review is summarizing on the one hand the state of the art in CAR T cell trials with a unique perspective on the role that Europe is playing. On the other hand, an overview of reproducible processing techniques is presented, from manual or semi-automated up to fully automated manufacturing of clinical-grade CAR T cells. Besides regulatory requirements, an outlook is given in the direction of digitally controlled automated manufacturing in order to lower cost and complexity and to address CAR T cell products for a greater number of patients and a variety of malignant diseases.

Recombinant oncolytic virus (OV) vaccines that encode tumour-associated antigens are potent boosting agents for adoptive transfer of tumor-specific T cells (adoptive T cell therapy or ACT). Current strategies to exploit boosting vaccines for ACT rely on a priori knowledge of targetable tumour epitopes and isolation of matched epitope-specific T cells. Therefore, booster vaccines must be developed on a patient-by-patient basis, which severely limits clinical feasibility. To overcome the requirement for individualized pairing of vaccines and T cells, we propose a “universal” strategy for boosting tumor-specific T cells where the boost is provided through a synthetic receptor that can be engineered into any T cell and a matched vaccine. To this end, we are employing chimeric antigen receptors (CARs), which confer MHC-independent antigen specificity to engineered T cells, and a paired OV vaccine that encodes the CAR target. As proof-of-concept, we have developed and evaluated a model where murine TCR transgenic T cells are engineered with boosting CARs against a surrogate antigen for studies in immunocompetent hosts. In chapter 3, I optimized a murine CAR-T cell manufacturing protocol that allows for generation of highly-transduced T cells that maintain a predominantly central memory (Tcm) phenotype. This protocol leads to generation of highly functional CAR-T cell products that can be cryopreserved at the end of ex vivo culture for future use in adoptive transfer and vaccination studies. In chapter 4, I evaluated the in vivo boosting potential of our dual-specific CAR-T cells with paired OV vaccines. Adoptive transfer of these CAR-engineered tumor-specific T cells followed by vaccination with paired oncolytic vesicular stomatitis virus (VSV) vaccine leads to robust, but variable and transient, CAR-mediated expansion of tumour-specific CD8+ T-cells, resulting in delayed tumour progression in aggressive syngeneic tumour models. In chapter 5, I investigated the role of OV-induced type I interferon (IFN-I) responses on CAR-T cell boosting. I found that CAR-T cell expansion and anti-tumour function following OV vaccination is limited by the IFN-I response and can be further enhanced by blocking interferon alpha and beta receptor subunit 1 (IFNAR1). This IFN-I-mediated T cell suppression was found to be T cell-extrinsic and related to premature termination of OV infection and antigen expression in vivo. In chapter 6, I investigated the role of CD4+ T cell help in vaccine-mediated T cell boosting and evaluated different genetic engineering strategies to integrate pro-survival STAT5 signaling into the CAR-T cell product in an effort to improve persistence and long-term anti-tumour efficacy. The work presented herein describes a novel and clinically feasible approach to enhancing adoptive T cell therapies and contributes to the basic understanding of T cell biology in the context of CAR-engineering and cancer vaccination. / Thesis / Doctor of Philosophy (PhD) / Despite recent advances in cancer prevention, detection, and treatment, 2 in 5 Canadians are expected to be diagnosed with cancer in their lifetime and approximately 1 in 4 will succumb to their disease. New, more specific therapies are needed to improve responses to treatment and reduce therapy-related side effects. Cell therapy is a new way to treat cancer that uses the patient’s own immune cells as a living drug. The immune cells are taken from a patient’s blood or tumour, trained to attack cancer in the laboratory, and infused back into the patient where they will find and kill cancer cells. A major challenge with this strategy is that the trained immune cells do not always survive in the patient for long enough to get rid of the tumour. To “boost” the immune cells, we are developing a new strategy where the immune cells are genetically modified and combined with a vaccine to enhance their anti-tumor activity. Just like a vaccine against a bacteria or virus, this vaccine will tell the modified immune cells to turn on, make more of themselves, and to find and kill the cancer cells. By delivering this “go” signal through a vaccine, we think that the immune cells will be better able to survive and generate a stronger, longer-lasting immune response against the cancer. This thesis tests this approach in relevant mouse models of cancer and aims to understand how we can best design the immune cells and vaccine to work together in their tumour-killing activities.

Immunotherapy for cancer is a young research field progressing at high speed. The first chimera of an antibody and a signaling chain was designed by Zelig Eshhar and was later further developed to enhance existing T cell therapy by combining a single-chain fragment of an antibody with the CD3 zeta chain of the TCR complex. T cells expressing these chimeric antigen receptors (CARs) could recognize and specifically kill tumor cells. However the T cells, lacked in persistence and tumor rejection did not occur. Thus, the CAR constructs have been improved by providing the T cell with costimulatory signals promoting activation. The focus of this thesis has been to evaluate second and third generation αCD19-CAR T cells for the treatment of B cell leukemia and lymphoma. B cell tumors commonly upregulate anti-apoptotic proteins such as Bcl-2, which generates therapy resistance. In the first paper a second generation (2G) αCD19-CD28-CAR T cell was combined with the Bcl-2 family inhibitor ABT-737. ABT-737 sensitized tumor cells to CAR T cell therapy and may be an interesting clinical combination treatment. In paper II, the phenotype and function of a third generation (3G) αCD19-CD28-4-1BB-CAR T cell were evaluated. B cell-stimulated CAR T cells showed increased proliferation and an antigen-driven accumulation of CAR+ T cells. 3G CAR T cells had equal cytotoxic capacity, similar lineage, memory and exhaustion profile phenotype compared to 2G CARs. However, 3G CAR T cells proliferated better and had increased activation of intracellular signaling pathways compared to 2G CAR T cells. In paper III, αCD19-CD28-4-1BB-CAR T cells were used to stimulate immature dendritic cells leading to an upregulation of maturation markers on co-cultured dendritic cells. Hence, CAR T cells may not only directly kill the tumor cells, but may induce bystander immunity that indirectly aids tumor control. This thesis also include supplementary information about the development and implementation of protocols for GMP production of CAR T cell batches for a phase I/IIa clinical trial currently ongoing for patients with refractory B cell leukemia and lymphoma. So far, two patients have safely been treated on the lowest dose.