RESUMO
BACKGROUND: Autologous BCMA-specific CAR T-cell therapies have substantial activity in multiple myeloma (MM). However, due to logistical limitations and BCMAlow relapses, there is a need for alternatives. UCARTCS1 cells are 'off-the-shelf' allogeneic CAR T-cells derived from healthy donors targeting SLAMF7 (CS1), which is highly expressed in MM cells. In this study, we evaluated the preclinical activity of UCARTCS1 in MM cell lines, in bone marrow (BM) samples obtained from MM patients and in an MM mouse model. METHODS: Luciferase-transduced MM cell lines were incubated with UCARTCS1 cells or control (non-transduced, SLAMF7/TCRαß double knock-out) T-cells at different effector to target ratios for 24 hours. MM cell lysis was assessed by bioluminescence. Anti-MM activity of UCARTCS1 was also evaluated in 29 BM samples obtained from newly diagnosed patients (n=10), daratumumab-naïve relapsed/refractory patients (n=10) and daratumumab-refractory patients (n=9) in 24-hour flow cytometry-based cytotoxicity assays. Finally, UCARTCS1 activity was assessed in mouse xenograft models. RESULTS: UCARTCS1 cells induced potent CAR-mediated, and dose-dependent lysis of both MM cell lines and primary MM cells. There was no difference in ex vivo activity of UCARTCS1 between heavily pretreated and newly diagnosed patients. In addition, efficacy of UCARTCS1 was not affected by SLAMF7 expression level on MM cells, proportion of tumor cells, or frequency of regulatory T-cells in BM samples obtained from MM patients. UCARTCS1 treatment eliminated SLAMF7+ non-malignant immune cells in a dose-dependent manner, however lysis of normal cells was less pronounced compared to that of MM cells. Additionally, durable anti-MM responses were observed with UCARTCS1 in an MM xenograft model. CONCLUSIONS: These results demonstrate that UCARTCS1 has potent anti-MM activity against MM cell lines and primary MM cells, as well as in an MM xenograft model and support the evaluation of UCARTCS1 in patients with advanced MM.
Assuntos
Imunoterapia Adotiva , Mieloma Múltiplo , Família de Moléculas de Sinalização da Ativação Linfocitária , Mieloma Múltiplo/terapia , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/patologia , Humanos , Animais , Família de Moléculas de Sinalização da Ativação Linfocitária/metabolismo , Camundongos , Imunoterapia Adotiva/métodos , Receptores de Antígenos Quiméricos/metabolismo , Receptores de Antígenos Quiméricos/imunologia , Ensaios Antitumorais Modelo de Xenoenxerto , Feminino , Linhagem Celular TumoralRESUMO
Sickle cell disease is a devastating blood disorder that originates from a single point mutation in the HBB gene coding for hemoglobin. Here, we develop a GMP-compatible TALEN-mediated gene editing process enabling efficient HBB correction via a DNA repair template while minimizing risks associated with HBB inactivation. Comparing viral versus non-viral DNA repair template delivery in hematopoietic stem and progenitor cells in vitro, both strategies achieve comparable HBB correction and result in over 50% expression of normal adult hemoglobin in red blood cells without inducing ß-thalassemic phenotype. In an immunodeficient female mouse model, transplanted cells edited with the non-viral strategy exhibit higher engraftment and gene correction levels compared to those edited with the viral strategy. Transcriptomic analysis reveals that non-viral DNA repair template delivery mitigates P53-mediated toxicity and preserves high levels of long-term hematopoietic stem cells. This work paves the way for TALEN-based autologous gene therapy for sickle cell disease.
Assuntos
Anemia Falciforme , Edição de Genes , Terapia Genética , Células-Tronco Hematopoéticas , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição , Anemia Falciforme/terapia , Anemia Falciforme/genética , Edição de Genes/métodos , Animais , Células-Tronco Hematopoéticas/metabolismo , Humanos , Feminino , Camundongos , Terapia Genética/métodos , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição/metabolismo , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição/genética , Transplante de Células-Tronco Hematopoéticas , Globinas beta/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Reparo do DNA , Mutação , Talassemia beta/terapia , Talassemia beta/genética , Modelos Animais de Doenças , Técnicas de Transferência de GenesRESUMO
Despite the remarkable success of autologous chimeric antigen receptor (CAR) T cells, some patients relapse due to tumor antigen escape and low or uneven antigen expression, among other mechanisms. Therapeutic options after relapse are limited, emphasizing the need to optimize current approaches. In addition, there is a need to develop allogeneic "off-the-shelf" therapies from healthy donors that are readily available at the time of treatment decision and can overcome limitations of current autologous approaches. To address both challenges simultaneously, we generated a CD20xCD22 dual allogeneic CAR T cell. Herein, we demonstrate that allogeneic CD20x22 CAR T cells display robust, sustained and dose-dependent activity in vitro and in vivo, while efficiently targeting primary B-cell non-Hodgkin lymphoma (B-NHL) samples with heterogeneous levels of CD22 and CD20. Altogether, we provide preclinical proof-of-concept data for an allogeneic dual CAR T cell to overcome current mechanisms of resistance to CAR T-cell therapies in B-NHL, while providing a potential alternative to CD19 targeting.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Linfoma de Células B , Humanos , Receptores de Antígenos de Linfócitos T , Recidiva Local de Neoplasia , Linfócitos T , Linfócitos B , Imunoterapia Adotiva , Antígenos CD19RESUMO
Herpes simplex virus (HSV) infection is a leading cause of corneal blindness. However, keratoplasty is only rarely proposed due to the high frequency of graft failure and associated recurrences. Gene therapy of the corneal graft might provide sustained protection against HSV infection. To test that hypothesis, we designed a meganuclease specific to an HSV-1 DNA sequence coding for major capsid protein (UL19) and selected an adeno-associated virus type-2 as the vector. Meganuclease was transduced into corneas and its effect was challenged in vitro, ex vivo, and then in vivo in a rabbit HSV-1-infection model of stromal keratitis and endotheliitis. In vivo, meganuclease exposure resulted in fewer infected stromal and endothelial cells, and protected against corneal opacification and edema. Ex vivo, HSV-1 infection rates of meganuclease-treated human corneas were drastically reduced. Furthermore, genetically engineered corneas transplanted in vivo into rabbit eyes protected against HSV-1 infection. This genome-editing technology targeting HSV-1 opens new opportunities to manage severe post-herpetic corneal blindness by providing infected patients with genetically protected corneal transplants.
RESUMO
Universal CAR T-cell therapies are poised to revolutionize cancer treatment and to improve patient outcomes. However, realizing these advantages in an allogeneic setting requires universal CAR T-cells that can kill target tumor cells, avoid depletion by the host immune system, and proliferate without attacking host tissues. Here, we describe the development of a novel immune-evasive universal CAR T-cells scaffold using precise TALEN-mediated gene editing and DNA matrices vectorized by recombinant adeno-associated virus 6. We simultaneously disrupt and repurpose the endogenous TRAC and B2M loci to generate TCRαß- and HLA-ABC-deficient T-cells expressing the CAR construct and the NK-inhibitor named HLA-E. This highly efficient gene editing process enables the engineered T-cells to evade NK cell and alloresponsive T-cell attacks and extend their persistence and antitumor activity in the presence of cytotoxic levels of NK cell in vivo and in vitro, respectively. This scaffold could enable the broad use of universal CAR T-cells in allogeneic settings and holds great promise for clinical applications.
Assuntos
Edição de Genes , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição , Humanos , Imunoterapia Adotiva , Receptores de Antígenos de Linfócitos T/genética , Linfócitos TRESUMO
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with poor outcomes with conventional therapy. Nearly 100% of BPDCNs overexpress interleukin 3 receptor subunit alpha (CD123). Given that CD123 is differentially expressed on the surface of BPDCN cells, it has emerged as an attractive therapeutic target. UCART123 is an investigational product consisting of allogeneic T cells expressing an anti-CD123 chimeric antigen receptor (CAR), edited with TALEN® nucleases. In this study, we examine the antitumor activity of UCART123 in preclinical models of BPDCN. We report that UCART123 have selective antitumor activity against CD123-positive primary BPDCN samples (while sparing normal hematopoietic progenitor cells) in the in vitro cytotoxicity and T cell degranulation assays; supported by the increased secretion of IFNγ by UCART123 cells when cultured in the presence of BPDCN cells. UCART123 eradicate BPDCN and result in long-term disease-free survival in a subset of primary patient-derived BPDCN xenograft mouse models. One potential challenge of CD123 targeting therapies is the loss of CD123 antigen through diverse genetic mechanisms, an event observed in one of three BPDCN PDX studied. In summary, these results provide a preclinical proof-of-principle that allogeneic UCART123 cells have potent anti-BPDCN activity.
Assuntos
Neoplasias Hematológicas , Transplante de Células-Tronco Hematopoéticas , Transtornos Mieloproliferativos , Neoplasias Cutâneas , Doença Aguda , Animais , Células Dendríticas/metabolismo , Neoplasias Hematológicas/tratamento farmacológico , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Subunidade alfa de Receptor de Interleucina-3/metabolismo , Camundongos , Transtornos Mieloproliferativos/metabolismo , Neoplasias Cutâneas/patologiaRESUMO
Acute myeloid leukemia (AML) is a disease with high incidence of relapse that is originated and maintained from leukemia stem cells (LSCs). Hematopoietic stem cells can be distinguished from LSCs by an array of cell surface antigens such as CD123, thus a candidate to eliminate LSCs using a variety of approaches, including CAR T cells. Here, we evaluate the potential of allogeneic gene-edited CAR T cells targeting CD123 to eliminate LSCs (UCART123). UCART123 cells are TCRαßneg T cells generated from healthy donors using TALEN® gene-editing technology, decreasing the likelihood of graft vs host disease. As safety feature, cells express RQR8 to allow elimination with Rituximab. UCART123 effectively eliminates AML cells in vitro and in vivo with significant benefits in overall survival of AML-patient derived xenograft mice. Furthermore, UCART123 preferentially target AML over normal cells with modest toxicity to normal hematopoietic stem/progenitor cells. Together these results suggest that UCART123 represents an off-the shelf therapeutic approach for AML.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda , Animais , Humanos , Subunidade alfa de Receptor de Interleucina-3/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/terapia , Camundongos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Linfócitos TRESUMO
CD70 is highly expressed in renal cell carcinoma (RCC), with limited expression in normal tissue, making it an attractive CAR T target for an immunogenic solid tumor indication. Here we generated and characterized a panel of anti-CD70 single-chain fragment variable (scFv)-based CAR T cells. Despite the expression of CD70 on T cells, production of CAR T cells from a subset of scFvs with potent in vitro activity was achieved. Expression of CD70 CARs masked CD70 detection in cis and provided protection from CD70 CAR T cell-mediated fratricide. Two distinct classes of CAR T cells were identified with differing memory phenotype, activation status, and cytotoxic activity. Epitope mapping revealed that the two classes of CARs bind unique regions of CD70. CD70 CAR T cells displayed robust antitumor activity against RCC cell lines and patient-derived xenograft mouse models. Tissue cross-reactivity studies identified membrane staining in lymphocytes, thus matching the known expression pattern of CD70. In a cynomolgus monkey CD3-CD70 bispecific toxicity study, expected findings related to T-cell activation and elimination of CD70-expressing cells were observed, including cytokine release and loss of cellularity in lymphoid tissues. Finally, highly functional CD70 allogeneic CAR T cells were produced at large scale through elimination of the T-cell receptor by TALEN-based gene editing. Taken together, these efficacy and safety data support the evaluation of CD70 CAR T cells for the treatment of RCC and has led to the advancement of an allogeneic CD70 CAR T-cell candidate into phase I clinical trials. SIGNIFICANCE: These findings demonstrate the efficacy and safety of fratricide-resistant, allogeneic anti-CD70 CAR T cells targeting renal cell carcinoma and the impact of CAR epitope on functional activity. See related commentary by Adotévi and Galaine, p. 2517.
Assuntos
Carcinoma de Células Renais , Transplante de Células-Tronco Hematopoéticas , Neoplasias Renais , Animais , Ligante CD27 , Carcinoma de Células Renais/patologia , Linhagem Celular Tumoral , Humanos , Imunoterapia Adotiva , Neoplasias Renais/patologia , Macaca fascicularis , Camundongos , Linfócitos T/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
We evaluate gene editing of HSV in a well-established mouse model, using adeno-associated virus (AAV)-delivered meganucleases, as a potentially curative approach to treat latent HSV infection. Here we show that AAV-delivered meganucleases, but not CRISPR/Cas9, mediate highly efficient gene editing of HSV, eliminating over 90% of latent virus from superior cervical ganglia. Single-cell RNA sequencing demonstrates that both HSV and individual AAV serotypes are non-randomly distributed among neuronal subsets in ganglia, implying that improved delivery to all neuronal subsets may lead to even more complete elimination of HSV. As predicted, delivery of meganucleases using a triple AAV serotype combination results in the greatest decrease in ganglionic HSV loads. The levels of HSV elimination observed in these studies, if translated to humans, would likely significantly reduce HSV reactivation, shedding, and lesions. Further optimization of meganuclease delivery and activity is likely possible, and may offer a pathway to a cure for HSV infection.
Assuntos
Desoxirribonucleases/genética , Dependovirus/genética , Infecções Oculares/terapia , Edição de Genes/métodos , Herpes Simples/terapia , Herpesvirus Humano 1/genética , Latência Viral/genética , Animais , Sistemas CRISPR-Cas/genética , Células Cultivadas , Chlorocebus aethiops , Infecções Oculares/genética , Infecções Oculares/virologia , Feminino , Células HEK293 , Herpes Simples/genética , Herpesvirus Humano 1/patogenicidade , Humanos , Camundongos , Neurônios/metabolismo , Neurônios/virologia , RNA-Seq , Análise de Célula Única , Gânglio Cervical Superior/metabolismo , Gânglio Cervical Superior/virologia , Células VeroRESUMO
Clinical success of autologous CD19-directed chimeric antigen receptor T cells (CAR Ts) in acute lymphoblastic leukemia and non-Hodgkin lymphoma suggests that CAR Ts may be a promising therapy for hematological malignancies, including multiple myeloma. However, autologous CAR T therapies have limitations that may impact clinical use, including lengthy vein-to-vein time and manufacturing constraints. Allogeneic CAR T (AlloCAR T) therapies may overcome these innate limitations of autologous CAR T therapies. Unlike autologous cell therapies, AlloCAR T therapies employ healthy donor T cells that are isolated in a manufacturing facility, engineered to express CARs with specificity for a tumor-associated antigen, and modified using gene-editing technology to limit T cell receptor (TCR)-mediated immune responses. Here, transcription activator-like effector nuclease (TALEN) gene editing of B cell maturation antigen (BCMA) CAR Ts was used to confer lymphodepletion resistance and reduced graft-versus-host disease (GvHD) potential. The safety profile of allogeneic BCMA CAR Ts was further enhanced by incorporating a CD20 mimotope-based intra-CAR off switch enabling effective CAR T elimination in the presence of rituximab. Allogeneic BCMA CAR Ts induced sustained antitumor responses in mice supplemented with human cytokines, and, most importantly, maintained their phenotype and potency after scale-up manufacturing. This novel off-the-shelf allogeneic BCMA CAR T product is a promising candidate for clinical evaluation.
Assuntos
Antígeno de Maturação de Linfócitos B/imunologia , Transplante de Células/métodos , Imunoterapia Adotiva/métodos , Mieloma Múltiplo/terapia , Receptores de Antígenos Quiméricos/imunologia , Linfócitos T/imunologia , Linfócitos T/transplante , Animais , Antineoplásicos Imunológicos/uso terapêutico , Antígeno de Maturação de Linfócitos B/genética , Doadores de Sangue , Linhagem Celular Tumoral , Transplante de Células/efeitos adversos , Citotoxicidade Imunológica/genética , Edição de Genes , Vetores Genéticos , Doença Enxerto-Hospedeiro/terapia , Humanos , Imunoterapia Adotiva/efeitos adversos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Mieloma Múltiplo/patologia , Intervalo Livre de Progressão , Receptores de Antígenos Quiméricos/genética , Receptores de Antígenos Quiméricos/metabolismo , Rituximab/uso terapêutico , Linfócitos T/metabolismo , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição/genética , Transdução Genética , Transplante Homólogo/métodosAssuntos
Anticorpos Monoclonais/imunologia , Antineoplásicos Imunológicos/uso terapêutico , Subunidade alfa de Receptor de Interleucina-3/análise , Leucemia Mieloide Aguda/imunologia , Citometria de Fluxo , Humanos , Imunofenotipagem/métodos , Subunidade alfa de Receptor de Interleucina-3/antagonistas & inibidores , Subunidade alfa de Receptor de Interleucina-3/imunologia , Leucemia Mieloide Aguda/tratamento farmacológico , Terapia de Alvo Molecular/métodos , Seleção de PacientesRESUMO
Pyruvate kinase deficiency (PKD) is a rare erythroid metabolic disease caused by mutations in the PKLR gene. Erythrocytes from PKD patients show an energetic imbalance causing chronic non-spherocytic hemolytic anemia, as pyruvate kinase defects impair ATP production in erythrocytes. We generated PKD induced pluripotent stem cells (PKDiPSCs) from peripheral blood mononuclear cells (PB-MNCs) of PKD patients by non-integrative Sendai viral vectors. PKDiPSCs were gene edited to integrate a partial codon-optimized R-type pyruvate kinase cDNA in the second intron of the PKLR gene by TALEN-mediated homologous recombination (HR). Notably, we found allele specificity of HR led by the presence of a single-nucleotide polymorphism. High numbers of erythroid cells derived from gene-edited PKDiPSCs showed correction of the energetic imbalance, providing an approach to correct metabolic erythroid diseases and demonstrating the practicality of this approach to generate the large cell numbers required for comprehensive biochemical and metabolic erythroid analyses.
Assuntos
Anemia Hemolítica Congênita não Esferocítica/genética , Anemia Hemolítica Congênita não Esferocítica/terapia , Células Eritroides/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Piruvato Quinase/deficiência , Piruvato Quinase/genética , Erros Inatos do Metabolismo dos Piruvatos/genética , Erros Inatos do Metabolismo dos Piruvatos/terapia , Alelos , Sequência de Bases , Contagem de Células , DNA Complementar/genética , Células Eritroides/metabolismo , Marcação de Genes , Terapia Genética , Humanos , Leucócitos Mononucleares/metabolismo , Recombinação GenéticaRESUMO
Adoptive immunotherapy using autologous T cells endowed with chimeric antigen receptors (CAR) has emerged as a powerful means of treating cancer. However, a limitation of this approach is that autologous CAR T cells must be generated on a custom-made basis. Here we show that electroporation of transcription activator-like effector nuclease (TALEN) mRNA allows highly efficient multiplex gene editing in primary human T cells. We use this TALEN-mediated editing approach to develop a process for the large-scale manufacturing of T cells deficient in expression of both their αß T-cell receptor (TCR) and CD52, a protein targeted by alemtuzumab, a chemotherapeutic agent. Functionally, T cells manufactured with this process do not mediate graft-versus-host reactions and are rendered resistant to destruction by alemtuzumab. These characteristics enable the administration of alemtuzumab concurrently or prior to engineered T cells, supporting their engraftment. Furthermore, endowing the TALEN-engineered cells with a CD19 CAR led to efficient destruction of CD19(+) tumor targets even in the presence of the chemotherapeutic agent. These results demonstrate the applicability of TALEN-mediated genome editing to a scalable process, which enables the manufacturing of third-party CAR T-cell immunotherapies against arbitrary targets. As such, CAR T-cell immunotherapies can therefore be used in an "off-the-shelf" manner akin to other biologic immunopharmaceuticals
Assuntos
Técnicas de Inativação de Genes , Imunoterapia Adotiva , Linfócitos T/transplante , Alemtuzumab , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais Humanizados/farmacologia , Antígenos CD/genética , Antígenos CD19/imunologia , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/imunologia , Sequência de Bases , Antígeno CD52 , Citotoxicidade Imunológica , Resistência a Medicamentos , Glicoproteínas/deficiência , Glicoproteínas/genética , Doença Enxerto-Hospedeiro/prevenção & controle , Humanos , Ativação Linfocitária , Linfoma/terapia , Camundongos , Camundongos Mutantes , Dados de Sequência Molecular , RNA Mensageiro , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/deficiência , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Transfecção , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
TALEN is one of the most widely used tools in the field of genome editing. It enables gene integration and gene inactivation in a highly efficient and specific fashion. Although very attractive, the apparent simplicity and high success rate of TALEN could be misleading for novices in the field of gene editing. Depending on the application, specific TALEN designs, activity assessments and screening strategies need to be adopted. Here we report different methods to efficiently perform TALEN-mediated gene integration and inactivation in different mammalian cell systems including induced pluripotent stem cells and delineate experimental examples associated with these approaches.
Assuntos
Marcação de Genes/métodos , Genoma/genética , Ativação Transcricional/genética , Transfecção/métodos , Animais , Sequência de Bases , Linhagem Celular , Proteínas de Ligação a DNA/genética , Células HCT116 , Humanos , Dados de Sequência MolecularRESUMO
Following acute infection, herpes simplex virus (HSV) establishes latency in sensory neurons, from which it can reactivate and cause recurrent disease. Available antiviral therapies do not affect latent viral genomes; therefore, they do not prevent reactivation following therapy cessation. One possible curative approach involves the introduction of DNA double strand breaks in latent HSV genomes by rare-cutting endonucleases, leading to mutagenesis of essential viral genes. We tested this approach in an in vitro HSV latency model using the engineered homing endonuclease (HE) HSV1m5, which recognizes a sequence in the HSV-1 gene UL19, encoding the virion protein VP5. Coexpression of the 3'-exonuclease Trex2 with HEs increased HE-mediated mutagenesis frequencies up to sixfold. Following HSV1m5/Trex2 delivery with adeno-associated viral (AAV) vectors, the target site was mutated in latent HSV genomes with no detectable cell toxicity. Importantly, HSV production by latently infected cells after reactivation was decreased after HSV1m5/Trex2 exposure. Exposure to histone deacetylase inhibitors prior to HSV1m5/Trex2 treatment increased mutagenesis frequencies of latent HSV genomes another two- to fivefold, suggesting that chromatin modification may be a useful adjunct to gene-targeting approaches. These results support the continuing development of HEs and other nucleases (ZFNs, TALENs, CRISPRs) for cure of chronic viral infections.Molecular Therapy-Nucleic Acids (2014) 3, e1; doi:10.1038/mtna.2013.75; published online 4 February 2014.
RESUMO
Chimeric antigen receptor technology offers a highly effective means for increasing the anti-tumor effects of autologous adoptive T-cell immunotherapy, and could be made widely available if adapted to the use of allogeneic T-cells. Although gene-editing technology can be used to remove the alloreactive potential of third party T-cells through destruction of either the α or ß T-cell receptor (TCR) subunit genes, this approach results in the associated loss of surface expression of the CD3 complex. This is nonetheless problematic as it results in the lack of an important trophic signal normally mediated by the CD3 complex at the cell surface, potentially compromising T-cell survival in vivo, and eliminating the potential to expand TCR-knockout cells using stimulatory anti-CD3 antibodies. Here, we show that pre-TCRα, a TCRα surrogate that pairs with TCRß chains to signal proper TCRß folding during T-cell development, can be expressed in TCRα knockout mature T-cells to support CD3 expression at the cell surface. Cells expressing pre-TCR/CD3 complexes can be activated and expanded using standard CD3/CD28 T-cell activation protocols. Thus, heterologous expression of pre-TCRα represents a promising technology for use in the manufacturing of TCR-deficient T-cells for adoptive immunotherapy applications.
RESUMO
Xeroderma pigmentosum group C (XP-C) is a rare human syndrome characterized by hypersensitivity to UV light and a dramatic predisposition to skin neoplasms. XP-C cells are deficient in the nucleotide excision repair (NER) pathway, a complex process involved in the recognition and removal of DNA lesions. Several XPC mutations have been described, including a founder mutation in North African patients involving the deletion of a TG dinucleotide (ΔTG) located in the middle of exon 9. This deletion leads to the expression of an inactive truncated XPC protein, normally involved in the first step of NER. New approaches used for gene correction are based on the ability of engineered nucleases such as Meganucleases, Zinc-Finger nucleases or TALE nucleases to accurately generate a double strand break at a specific locus and promote correction by homologous recombination through the insertion of an exogenous DNA repair matrix. Here, we describe the targeted correction of the ΔTG mutation in XP-C cells using engineered meganuclease and TALEN™. The methylated status of the XPC locus, known to inhibit both of these nuclease activities, led us to adapt our experimental design to optimize their in vivo efficacies. We show that demethylating treatment as well as the use of TALEN™ insensitive to CpG methylation enable successful correction of the ΔTG mutation. Such genetic correction leads to re-expression of the full-length XPC protein and to the recovery of NER capacity, attested by UV-C resistance of the corrected cells. Overall, we demonstrate that nuclease-based targeted approaches offer reliable and efficient strategies for gene correction.
Assuntos
Desoxirribonucleases/genética , Xeroderma Pigmentoso/terapia , Sequência de Bases , Linhagem Celular , Clivagem do DNA , Metilação de DNA , Reparo do DNA , Proteínas de Ligação a DNA/genética , Epigênese Genética , Terapia Genética , Humanos , Mutagênese , Fenótipo , Engenharia de ProteínasRESUMO
Integrative gene transfer is widely used for bioproduction, drug screening, and therapeutic applications but usual viral methods lead to random and multicopy insertions, contribute to unstable transgene expression and can disturb endogenous gene expression. Homologous targeting of an expression cassette using rare-cutting endonucleases is a potential solution; however the number of studied loci remains limited. Furthermore, the behavior and performance of various types of gene cassettes following gene targeting is poorly defined. Here we have evaluated three loci for gene targeting, including one locus compatible with the proposed Safe Harbor criteria for human translational applications. Using optimized conditions for homologous gene targeting, reporter genes under the control of different promoters were efficiently inserted at each locus in both sense and antisense orientations. Sustainable expression was achieved at all three loci without detectable disturbance of flanking gene expression. However, the promoter, the integration locus and the cassette orientation have a strong impact on transgene expression. Finally, single targeted integrations exhibited greatly improved transgene expression stability versus multicopy or random integration. Taken together, our data suggest a potential set of loci for site-specific transgene integration, suitable for a variety of biotechnological applications.
Assuntos
Expressão Gênica , Marcação de Genes , Mutagênese Insercional/métodos , Transgenes , Biotecnologia/métodos , Linhagem Celular , Genes Reporter , Instabilidade Genômica , Humanos , Regiões Promotoras GenéticasRESUMO
The ability to specifically engineer the genome of living cells at precise locations using rare-cutting designer endonucleases has broad implications for biotechnology and medicine, particularly for functional genomics, transgenics and gene therapy. However, the potential impact of chromosomal context and epigenetics on designer endonuclease-mediated genome editing is poorly understood. To address this question, we conducted a comprehensive analysis on the efficacy of 37 endonucleases derived from the quintessential I-CreI meganuclease that were specifically designed to cleave 39 different genomic targets. The analysis revealed that the efficiency of targeted mutagenesis at a given chromosomal locus is predictive of that of homologous gene targeting. Consequently, a strong genome-wide correlation was apparent between the efficiency of targeted mutagenesis (≤ 0.1% to ≈ 6%) with that of homologous gene targeting (≤ 0.1% to ≈ 15%). In contrast, the efficiency of targeted mutagenesis or homologous gene targeting at a given chromosomal locus does not correlate with the activity of individual endonucleases on transiently transfected substrates. Finally, we demonstrate that chromatin accessibility modulates the efficacy of rare-cutting endonucleases, accounting for strong position effects. Thus, chromosomal context and epigenetic mechanisms may play a major role in the efficiency rare-cutting endonuclease-induced genome engineering.
Assuntos
Efeitos da Posição Cromossômica , Enzimas de Restrição do DNA/metabolismo , Animais , Células CHO , Linhagem Celular , Cricetinae , Cricetulus , Enzimas de Restrição do DNA/química , Marcação de Genes , Engenharia Genética , Genoma Humano , Humanos , MutagêneseRESUMO
The importance of safer approaches for gene therapy has been underscored by a series of severe adverse events (SAEs) observed in patients involved in clinical trials for Severe Combined Immune Deficiency Disease (SCID) and Chromic Granulomatous Disease (CGD). While a new generation of viral vectors is in the process of replacing the classical gamma-retrovirus-based approach, a number of strategies have emerged based on non-viral vectorization and/or targeted insertion aimed at achieving safer gene transfer. Currently, these methods display lower efficacies than viral transduction although many of them can yield more than 1% of engineered cells in vitro. Nuclease-based approaches, wherein an endonuclease is used to trigger site-specific genome editing, can significantly increase the percentage of targeted cells. These methods therefore provide a real alternative to classical gene transfer as well as gene editing. However, the first endonuclease to be in clinic today is not used for gene transfer, but to inactivate a gene (CCR5) required for HIV infection. Here, we review these alternative approaches, with a special emphasis on meganucleases, a family of naturally occurring rare-cutting endonucleases, and speculate on their current and future potential.