Development Of Cell Therapies Research Articles

CT-159 Precise Measurement of Transduction Efficiency at Single-Cell Resolution for Cell Therapy Development

Cell and gene therapies are transformative solutions for a host of inherited and acquired diseases for which existing interventions are ineffective. Many such therapies rely on the introduction of transgenes into host cells using viral or non-viral vectors. Unlike most small molecule drugs, this approach offers long-term benefits and may even serve as a curative solution. The accurate measurement of gene transfer is critical to the development of therapeutic agents and is a key attribute for assessing their safety and efficacy. Yet, conventional methods for measuring gene transfer either report a population average (bulk) or involve time-consuming clonal outgrowth. Here, we demonstrate that single-cell DNA sequencing identifies transduced versus non-transduced cells with exceptional accuracy and precision for populations of up to 10,000 cells. Cells were transduced with lentivirus containing a unique genetic sequence and were then diluted with non-transduced cells to achieve roughly 0, 25, 50, 75, and 100% of positively transduced cells. Five replicates from each concentration were then quantified using Mission Bio's Tapestri Platform, an instrument that leverages droplet microfluidics to enable the targeting and sequencing of DNA in 1,000s of individual cells. The data were analyzed using Tapestri proprietary software. The dilution series showed excellent linearity (R2 greater than 0.99) and precision among replicates (%CV's below 5%) between the expected and observed transduction percentages. For the 5 replicates of non-transduced cells, the false positive rate was below 0.03%. This study showcases the ability of single-cell DNA sequencing to accurately report the percentage of positively transduced cells in a single high-throughput assay without the need for tedious single-cell isolations and clonal outgrowth. Single-cell DNA sequencing offers exciting new capabilities for the development of in vivo and ex vivo cell and gene therapies. By precisely measuring the presence or absence of viral DNA on a per cell basis, researchers can quickly optimize gene transfer protocols during preclinical development, clinical trials and batch release testing during cell product manufacturing.

Poster: CT-159 Precise Measurement of Transduction Efficiency at Single-Cell Resolution for Cell Therapy Development

Poster: CT-159 Precise Measurement of Transduction Efficiency at Single-Cell Resolution for Cell Therapy Development

In vivo generation of bone marrow from embryonic stem cells in interspecies chimeras.

Generation of bone marrow (BM) from embryonic stem cells (ESCs) promises to accelerate the development of future cell therapies for life-threatening disorders. However, such approach is limited by technical challenges to produce a mixture of functional BM progenitor cells able to replace all hematopoietic cell lineages. Herein, we used blastocyst complementation to simultaneously produce BM cell lineages from mouse ESCs in a rat. Based on fluorescence-activated cell sorting analysis and single-cell RNA sequencing, mouse ESCs differentiated into multiple hematopoietic and stromal cell types that were indistinguishable from normal mouse BM cells based on gene expression signatures and cell surface markers. Receptor-ligand interactions identified Cxcl12-Cxcr4, Lama2-Itga6, App-Itga6, Comp-Cd47, Col1a1-Cd44, and App-Il18rap as major signaling pathways between hematopoietic progenitors and stromal cells. Multiple hematopoietic progenitors, including hematopoietic stem cells (HSCs) in mouse-rat chimeras derived more efficiently from mouse ESCs, whereas chondrocytes predominantly derived from rat cells. In the dorsal aorta and fetal liver of mouse-rat chimeras, mouse HSCs emerged and expanded faster compared to endogenous rat cells. Sequential BM transplantation of ESC-derived cells from mouse-rat chimeras rescued lethally irradiated syngeneic mice and demonstrated long-term reconstitution potential of donor HSCs. Altogether, a fully functional BM was generated from mouse ESCs using rat embryos as 'bioreactors'.

Differentiation Capacity of Bone Marrow-Derived Rat Mesenchymal Stem Cells from DsRed and Cre Transgenic Cre/loxP Models

Cre/loxP recombination is a well-established technique increasingly used for modifying DNA both in vitro and in vivo. Nucleotide alterations can be edited in the genomes of mammalian cells, and genetic switches can be designed to target the expression or excision of a gene in any tissue at any time in animal models. In this study, we propose a system which worked via the Cre/loxP switch gene and DsRed/emGFP dual-color fluorescence imaging. Mesenchymal stem cells (MSCs) can be used to regenerate damaged tissue because of their differentiation capacity. Although previous studies have presented evidence of fusion of transplanted MSCs with recipient cells, the possibility of fusion in such cases remains debated. Moreover, the effects and biological implications of the fusion of MSCs at the tissue and organ level have not yet been elucidated. Thus, the method for determining this issue is significant and the models we proposed can illustrate the question. However, the transgenic rats exhibited growth slower than that of wild-type rats over several weeks. The effects on the stemness, proliferation, cell cycle, and differentiation ability of bone marrow–derived rat MSCs (BM-rMSCs) from the models were examined to ensure our design was appropriate for the in vivo application. We demonstrated that MSC surface markers were maintained in DsRed and Cre transgenic rMSCs (DsRed-rMSCs and Cre-rMSCs, respectively). A WST-8 assay revealed decreased proliferative activity in these DsRed-rMSCs and Cre-rMSCs; this result was validated through cell counting. Furthermore, cell cycle analysis indicated a decrease in the proportion of G1-phase cells and a concomitant increase in the proportion of S-phase cells. The levels of cell cycle–related proteins also decreased in the DsRed-rMSCs and Cre-rMSCs, implying decelerated phase transition. However, the BM-rMSCs collected from the transgenic rats did not exhibit altered adipogenesis, osteogenesis, or chondrogenesis. The specific markers of these types of differentiation were upregulated after induction. Therefore, BM-rMSCs from DsRed and Cre transgenic models can be used to investigate the behavior of MSCs and related mechanisms. Such application may further the development of stem cell therapy for tissue damage and other diseases.

A closed, modular approach to autologous CAR T cell therapy manufacturing

Watch this video to gain an in-depth understanding of Thermo Fisher Scientific’s digitally compatible, GMP-compliant manufacturing platform to produce CAR T cells.In this video you will see:Preparation of media and reagents used for cell isolation and activationSet up of consumable and instrument for cell processing using the Gibco CTS Rotea Counterflow Centrifugation SystemIsolation and activation of the cells using the Gibco CTS DynaMag Magnet and CTS Rotea SystemTransfer of the target cells to the bioreactor using the Thermo Scientific HyPerforma G3Lab controller for culture and lentiviral infectionBead removal, cell wash and concentrate and cryopreservation of the final CAR T cell productJason Isaacson is a scientist in the Cell and Gene Therapy business on the Cell Therapy Innovations team at Thermo Fisher Scientific. He is responsible for development and optimization of end-to-end cell therapy workflow solutions that integrate Thermo Fisher’s closed, automated instrumentation platforms. Prior to this role, Jason has gained experience across many industrial environments from large pharma, to small biotech and startups. His extensive experience in research includes 10 years developing HIV small molecule inhibitors, 7 years developing small molecule inhibitors for various oncology targets, and 7 years working with T cell and NK cell therapy development.

Researches on Stem and Progenitor Cells in Intervertebral Discs: An Analysis of the Scientific Landscape.

Low back pain (LBP) is a common clinical symptom, and the prevalence is ranged from 60% to 70%. With the deepening of basic research, the development of intervertebral disc regeneration-oriented cell therapy, especially stem and progenitor cells therapy, showed good research prospects and was expected to become new methods of treatment for LBP. Our study is aimed at analyzing the scientific output of stem and progenitor cells in intervertebral discs and at driving future research into new publications. Researches focused on this file were searched from the Science Citation Index Expanded (SCI-E) of the Web of Science (WOS) core collection database and were screened according to inclusion criteria. We evaluated and visualized the results, including annual publications, citations, authors, organizations, countries, research directions, funds, and journals by bibliometric website, VOSviewer, and Citespace softwares on May 27, 2022. A total of 450 original articles and reviews were included, and the overall trend of the number of publications rapidly increased. In worldwide, China and the USA were the leading countries for research production. The retrieved 450 publications received 14322 citations, with an average of 31.83 citations and an H-index of 62. The most high-yield author, organization, country, research directions, funds, and journals were Chen QX from Zhejiang University, Zhejiang University, China, Cell Biology, National Natural Science Foundation of China, and Spine, respectively. Keywords cluster analysis showed the research hotspots in the future, including “human intervertebral disc”, “adipose-derived mesenchymal stem cell”, “intervertebral disc degeneration”, “degenerative disc model”, “nucleus pulposus regeneration”, “human cartilage”, “3d culture”, “shrinkage-free preparation”, and “polylactide disc”. Furthermore, with accumulating evidence demonstrating the role of stem and progenitor cells in intervertebral discs, “microenvironment”, “activation”, “intervertebral disc degeneration”, and “oxidative stress” are becoming the research frontiers and trends.

Ceiling culture of human mature white adipocytes with a browning agent: A novel approach to induce transdifferentiation into beige adipocytes.

Excess and dysfunctional adipose tissue plays an important role in metabolic diseases, including obesity, atherosclerosis and type 2 diabetes mellitus. In mammals, adipose tissue is categorized into two types: white and brown. Adult brown tissue is mainly composed of beige adipocytes, which dispose of stored energy as heat and have become increasingly popular as a therapeutic target for obesity. However, there is still a paucity of cell models that allow transdifferentiation of mature white adipocytes into beige adipocytes, as seen in vivo. Here, we describe a novel, ceiling culture-based model of human mature white adipocytes, which transdifferentiate into beige adipocytes under the mechanical force and hypoxia of ceiling culture. We also show that the use of rosiglitazone and rapamycin can modulate transdifferentiation, up and down regulating expression of beige adipocyte-specific genes, respectively. Rosiglitazone additionally facilitated the upregulation of fatty acid lipolysis and oxidation genes. Finally, these beige adipocytes derived from dedifferentiated adipocytes exhibited a progenitor-specific phenotype, with higher expression of mature adipocyte-specific genes than adipocyte-derived stem cells. Overall, we report a novel approach to conveniently cultivate beige adipocytes from white adipocytes in vitro, suitable for mechanistic studies of adipose biology and development of cell and drug therapies in the future.

SYST-15 TARGETING AXONAL GUIDANCE WITH ANTI-ROBO1 CAR T CELLS: A NEW THERAPEUTIC STRATEGY FOR MALIGNANT BRAIN CANCER

Abstract No standardized treatments exist for patients with treatment-refractory brain metastasis, glioblastoma and other recurrent brain tumours. Given the aggressive nature of these diseases and difficulty in modelling tumour recurrence, minimal efforts have been made to design rational therapies against them. Neurodevelopmental pathways are often highjacked and go awry in the progression of these cancers. The roundabout guidance receptor 1 (ROBO1) protein is involved in axonal guidance during neurodevelopment, and we have shown that aberrant ROBO signalling promotes invasiveness and tumour growth in glioblastoma. Likewise, this signalling may contribute to the metastasis and growth of metastatic brain tumours, making the ROBO1-expressing tumour cell population an attractive and functionally relevant therapeutic target. Here, we present that ROBO1 is highly expressed on the surface of malignant and treatment-refractory brain tumour initiating cells (BTICs), prompting the development of an anti-ROBO1 CAR-T cell therapy. Using the binding region of a single-domain antibody targeting ROBO1, we developed second-generation anti-ROBO1 CAR-T cells specific and effective against malignant brain cancers, upregulating markers of activation and degranulation upon exposure to ROBO1-expressing BTICs. Additionally, orthotopic patient-derived xenograft models of malignant brain tumours treated with anti-ROBO1 CAR-T cells had a reduced tumour burden and prolonged survival, demonstrating therapeutic potential for treating brain malignancies.

Genome Engineering for Next-Generation Cellular Immunotherapies.

Over the past decade, cellular immunotherapies such as CAR-T, TCR-T, and NK cell therapies have achieved tremendous success in cancer treatment. However, various challenges and obstacles remain, including antigen escape, immunosuppression in the tumor microenvironment, toxicities, and on-target off-tumor effects. Recent strategies for overcoming these roadblocks have included the use of genome engineering. Multiplexed CRISPR-Cas and synthetic biology approaches facilitate the development of cell therapies with higher potency and sophisticated modular control; they also offer a toolkit for allogeneic therapy development. Engineering approaches have targeted genetic modifications to enhance long-term persistence through cytokine modulation, knockout of genes mediating immunosuppressive signals, and genes such as the endogenous TCR and MHC-I that elicit adverse host-graft interactions in an allogeneic context. Genome engineering approaches for other immune cell types are also being explored, such as CAR macrophages and CAR-NK cells. Future therapeutic development of cellular immunotherapies may also be guided by novel target discovery through unbiased CRISPR genetic screening approaches.

The Ultramarathon of Gene Therapy Development for Rare Diseases: How Can We Cross the Finish Line Together?

The promising developments in gene and cell therapy bring an array of hope to the >7000 rare disease patient communities, of which 90% to 95% are still working toward a treatment. However, the pace of gene and cell therapy development pathways often resembles ultramarathon relay races that potentially span decades. It is a pace that is incongruent to the sprint that most individuals with rare diseases and their families are living and working in pursuit of life-saving treatments. It is also challenging for the medical professionals, academic researchers, and pharmaceutical partners working tirelessly to bring a treatment to reality. Gene and cell therapy development programs can have many parallels to an ultramarathon, including extensive training and preparation leading up to clinical trials, selecting inclusion and exclusion criteria, supporting trial participants, and creating support teams. All aspects of the development course carry the greatest hope that as many treatments as possible can cross the finish line. Drawing on this analogy, perspectives and insights from a patient family member and rare disease advocacy leader in a community that has experienced its first clinical trial of gene therapy is shared. Bringing attention to these experiences, challenges, barriers, and potential learnings from a patient family perspective will likely encourage continued improvements in development of patient-driven gene and cell drug and therapy for the rare disease community.

The steep uphill path leading to ex vivo gene therapy for genodermatoses.

Cell therapy, gene therapy, and tissue engineering have the potential to revolutionize the field of regenerative medicine. In particular, gene therapy is understood as the therapeutical correction of mutated genes by addition of a correct copy of the gene or site-specific gene modifications. Gene correction of somatic stem cells sustaining renewing tissues is critical to ensure long-term clinical success of ex vivo gene therapy. To date, remarkable clinical outcomes arose from combined ex vivo cell and gene therapy of different genetic diseases, such as immunodeficiencies and genodermatoses. Despite the efforts of researchers around the world, only a few of these advanced approaches have yet made it to routine therapy. In fact, gene therapy poses one of the greatest technical challenges in modern medicine, spanning safety and efficacy issues, regulatory constraints, registration and market access, all of which need to be addressed to make the therapy available to patients with rare disease. In this review, we survey some of the main challenges in the development of combined cell and gene therapy of genetic skin diseases.

Recent advances and clinical pharmacology aspects of Chimeric Antigen Receptor (CAR) T-cellular therapy development.

Advances in immuno‐oncology have provided a variety of novel therapeutics that harness the innate immune system to identify and destroy neoplastic cells. It is noteworthy that acceptable safety profiles accompany the development of these targeted therapies, which result in efficacious cancer treatment with higher survival rates and lower toxicities. Adoptive cellular therapy (ACT) has shown promising results in inducing sustainable remissions in patients suffering from refractory diseases. Two main types of ACT include engineered Chimeric Antigen Receptor (CAR) T cells and T cell receptor (TCR) T cells. The application of these immuno‐therapies in the last few years has been successful and has demonstrated a safe and rapid treatment regimen for solid and non‐solid tumors. The current review presents an insight into the clinical pharmacology aspects of immuno‐therapies, especially CAR‐T cells. Here, we summarize the current knowledge of TCR and CAR‐T cell immunotherapy with particular focus on the structure of CAR‐T cells, the effects and toxicities associated with these therapies in clinical trials, risk mitigation strategies, dose selection approaches, and cellular kinetics. Finally, the quantitative approaches and modeling techniques used in the development of CAR‐T cell therapies are described.

Role of Metabolism in Adoptive T Cell Therapy: Strategies and Challenges.

Significance: Immune cell therapy involves the administration of immune cells into patients, and it has emerged as one of the most common type of immunotherapy for cancer treatment. Knowledge on the biology and metabolism of the adoptively transferred immune cells and the metabolic requirements of different cell types in the tumor is fundamental for the development of immune cell therapy with higher efficacy. Recent Advances: Adoptive T cell therapy has been shown to be effective in limited types of cancer. Different types and generations of adoptive T cell therapies have evolved in the recent decade. This review covers the basic principles and development of these therapies in cancer treatment. Critical Issues: Our review provides an overview on the basic concepts on T cell metabolism and highlights the metabolic requirements of T and adoptively transferred T cells. Future Directions: Integrating the knowledge just cited will facilitate the development of strategies to maximize the expansion of adoptively transferred T cells ex vivo and in vivo and to promote their durability and antitumor effects. Antioxid. Redox Signal. 37, 1303-1324.

Diffuse Choroidal Dystrophies

Hereditary diffuse choroidal dystrophies are conditions with atrophy especially in choriocapillaris, retinal pigment epithelium, and outer retinal layers. Choroideremia transmitted by X recessive inheritance and autosomal recessive Gyrate atrophy is common choroidal dystrophies. In the first decades, these two groups of diseases, whose symptoms begin with a decrease in night vision, progress with a progressive decrease in vision in the advanced decades as the pigmentary changes in the peripheral retina are also affected by the central retina. In Gyrate atrophy, progressive vision decrease and ocular complications can be stopped with dietary changes. However, the development of gene therapy and stem cell therapies for choroideremia is promising.

Advances and challenges in photoreceptor repair and regeneration

<p indent="0mm">Vision relies on converting light into electrical signals and sequentially transmitting the electrical signals along a visual pathway. Photon reception and electrical signal conversion is the first step in vision, which is carried out by a specialized type of retinal neuron called the photoreceptor. Loss of photoreceptors leads to irreversible retinal degeneration and blindness, and currently, there is no cure. Gene therapy is expected to relieve some hereditary retinal degenerative diseases. The first and the only by far gene-drug LUXTURNA® was approved by the US FDA in 2017 for the treatment of Leber congenital amaurosis (LCA). However, the high cost ($850,000/person) and narrow treatment window make it unavailable for most patients with RPE65 mutations. Recent advances in the differentiation of embryonic stem cells and induced pluripotent stem cells and in transdifferentiation of endogenous Müller cells provide hope for regenerating photoreceptors and will provide new routes for treating degenerative retinal diseases. This review focuses on the ongoing development of gene and stem cell therapies, highlighting the current advances and challenges in photoreceptor repair and regeneration.

Newer therapeutic options for inherited retinal diseases: Gene and cell replacement therapy.

Inherited retinal diseases (IRD) are genotypically and phenotypically varied disorders that lead to progressive degeneration of the outer retina and the retinal pigment epithelium (RPE) eventually resulting in severe vision loss. Recent research and developments in gene therapy and cell therapy have shown therapeutic promise in these hitherto incurable diseases. In gene therapy, copies of a healthy gene are introduced into the host cells via a viral vector. Clinical trials for several genes are underway while treatment for RPE65 called voretigene neparvovec, is already approved and commercially available. Cell therapy involves the introduction of stem cells that can replace degenerated cells. These therapies are delivered to the target tissues, namely the photoreceptors (PR) and RPE via subretinal, intravitreal, or suprachoroidal delivery systems. Although there are several limitations to these therapies, they are expected to slow the disease progression and restore some visual functions. Further advances such as gene editing technologies are likely to result in more precise and personalized treatments. Currently, several IRDs such as retinitis pigmentosa, Stargardt disease, Leber congenital amaurosis, choroideremia, achromatopsia, and Usher syndrome are being evaluated for possible gene therapy or cell therapy. It is important to encourage patients to undergo gene testing and maintain a nationwide registry of IRDs. This article provides an overview of the basics of these therapies and their current status.

P1435: PRECLINICAL EVALUATION OF ZILOVERTAMAB-BASED ANTI-ROR1 CHIMERIC ANTIGEN RECEPTORS IN NK AND T CELLS

Background: The receptor tyrosine kinase-like orphan receptor ROR1 is a promising target for immunotherapies of many cancers, including mantle cell lymphoma, diffuse large B-cell lymphoma, B-cell acute lymphocytic leukemia and chronic lymphocytic leukemia. Normally only expressed during embryonic development and only minimally, if at all, in adult normal tissues, ROR1 is overexpressed on malignant cells. Zilovertamab is a monoclonal antibody binding ROR1 that is currently in Phase 1/2 clinical trials. The antibody blocks survival signals mediated by Wnt5a via the ROR1 receptor. A different approach is the use of the antigen binding domain of the antibody in chimeric antigen receptors (CARs) expressed in NK or T cells to induce cellular cytotoxicity against ROR1-expressing cancer cells. Aims: This study aimed to evaluate different CAR designs in NK cells and T cells for cytotoxicity and cytokine production in vitro and control of cancer growth in a murine in vivo model. Methods: Two CARs using different linkers between the single chain antibody fragment (scFv) and the transmembrane domain were designed and cloned into lentiviral vectors. The two constructs were expressed in the cell line NK92 and the cells’ response against ROR1-positive and negative cancer cell lines was measured by degranulation and interferon-γ production. The construct that showed a stronger activation was tested in an in vivo model. Immune deficient NSG mice were injected with ROR1-positive JEKO-1 cells transgenic for luciferase. The cancer cell burden was monitored by intravital imaging. When cancer cell growth was established, the mice received either 1, 3, or 9 x 106 human T cells expressing the CAR or untransduced T cells. Results: NK92 cells expressing either of the two CARs showed enhanced degranulation and IFN-γ production in response to the ROR1-expressing cancer cell lines RPMI 8226 and JEKO-1. NK cells expressing the CAR containing the shorter linker between the scFv and the transmembrane domain exhibited higher activation levels. Primary human T cells expressing this CAR construct demonstrated degranulation and cytokine production during co-incubation with the ROR1-expressing JEKO-1 cell line but not the ROR1-negative Jurkat cell line. Injection of anti-ROR1 human CAR-T cells into NSG mice with established cancer growth greatly reduced the cell burden of JEKO-1 while untransduced T cells were unable to control cancer cell growth. Summary/Conclusion: The zilovertamab-based CAR tested in this study enhances the NK cell response towards ROR1-expressing cancer cells and enables T cells to clear fast-growing cancer cells in an in vivo model. These findings support the development of anti-ROR1 cell therapies for the potential treatment of ROR1-positive hematological malignancies.

Cell therapy in corneal endothelial disease.

Endothelial keratoplasty is the current gold standard for treating corneal endothelial diseases, achieving excellent visual outcomes and rapid rehabilitation. There are, however, severe limitations to donor tissue supply and uneven access to surgical teams and facilities across the globe. Cell therapy is an exciting approach that has shown promising early results. Herein, we review the latest developments in cell therapy for corneal endothelial disease. We highlight the work of several groups that have reported successful functional outcomes of cell therapy in animal models, with the utilization of human embryonic stem cells, human-induced pluripotent stem cells and cadaveric human corneal endothelial cells (CECs) to generate populations of CECs for intracameral injection. The use of corneal endothelial progenitors, viability of cryopreserved cells and efficacy of simple noncultured cells, in treating corneal decompensation is of particular interest. Further additions to the collective understanding of CEC physiology, and the process of cultivating and administering effective cell therapy are reviewed as well. The latest developments in cell therapy for corneal endothelial disease are presented. The continuous growth in this field gives rise to the hope that a viable solution to the large numbers of corneal blind around the world will one day be reality.

Process Development for Adoptive Cell Therapy in Academia: A Pipeline for Clinical-Scale Manufacturing of Multiple TCR-T Cell Products.

Cellular immunotherapies based on T cell receptor (TCR) transfer are promising approaches for the treatment of cancer and chronic viral infections. The discovery of novel receptors is expanding considerably; however, the clinical development of TCR-T cell therapies still lags. Here we provide a pipeline for process development and clinical-scale manufacturing of TCR-T cells in academia. We utilized two TCRs specific for hepatitis C virus (HCV) as models because of their marked differences in avidity and functional profile in TCR-redirected cells. With our clinical-scale pipeline, we reproduced the functional profile associated with each TCR. Moreover, the two TCR-T cell products demonstrated similar yield, purity, transduction efficiency as well as phenotype. The TCR-T cell products had a highly reproducible yield of over 1.4 × 109 cells, with an average viability of 93%; 97.8–99% of cells were CD3+, of which 47.66 ± 2.02% were CD8+ T cells; the phenotype was markedly associated with central memory (CD62L+CD45RO+) for CD4+ (93.70 ± 5.23%) and CD8+ (94.26 ± 4.04%). The functional assessments in 2D and 3D cell culture assays showed that TCR-T cells mounted a polyfunctional response to the cognate HCV peptide target in tumor cell lines, including killing. Collectively, we report a solid strategy for the efficient large-scale manufacturing of TCR-T cells.

Abstract 564: Targeting axonal guidance with anti-ROBO1 CAR T cells: A new therapeutic strategy for malignant brain cancer

Abstract No standardized treatment exists for patients with recurrent glioblastoma (GBM). Given the aggressive nature of the disease and difficulty in modeling tumor recurrence, minimal efforts have been made to design rational therapies against it. The roundabout guidance receptor 1 (ROBO1) protein is involved in axonal guidance during neurodevelopment and is aberrantly upregulated in glioma where it mediates glioma cell migration. Here, we present that ROBO1 is highly expressed on the surface of malignant and treatment-refractory brain tumor initiating cells (BTICs), prompting the development of an anti-ROBO1 CAR-T cell therapy. Using the binding region of a single-domain antibody targeting ROBO1, we developed second-generation anti-ROBO1 CAR-T cells specific and effective against ROBO1-expressing BTICs. Upon antigen exposure, anti-ROBO1 CAR-T cells upregulated markers of activation and degranulation. Additionally, treatment of orthotopic and patient-derived brain tumor xenograft models with anti-ROBO1 CAR-T cells resulted in reduced tumor burden and prolonged survival, demonstrating the therapy’s therapeutic potential for treating neoplastic brain malignancies. Citation Format: Sheila Kumari Singh, Chirayu R. Chokshi, Benjamin Brakel, Martin A. Rossotti, Chitra Venugopal, Sabra Salim, Kevin Henry. Targeting axonal guidance with anti-ROBO1 CAR T cells: A new therapeutic strategy for malignant brain cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 564.