Publications by authors named "Karin Straathof"

27 Publications

  • Page 1 of 1

Somatic mutations and single-cell transcriptomes reveal the root of malignant rhabdoid tumours.

Nat Commun 2021 03 3;12(1):1407. Epub 2021 Mar 3.

Princess Máxima Center for Pediatric Oncology, 3584CS, Utrecht, the Netherlands.

Malignant rhabdoid tumour (MRT) is an often lethal childhood cancer that, like many paediatric tumours, is thought to arise from aberrant fetal development. The embryonic root and differentiation pathways underpinning MRT are not firmly established. Here, we study the origin of MRT by combining phylogenetic analyses and single-cell mRNA studies in patient-derived organoids. Comparison of somatic mutations shared between cancer and surrounding normal tissues places MRT in a lineage with neural crest-derived Schwann cells. Single-cell mRNA readouts of MRT differentiation, which we examine by reverting the genetic driver mutation underpinning MRT, SMARCB1 loss, suggest that cells are blocked en route to differentiating into mesenchyme. Quantitative transcriptional predictions indicate that combined HDAC and mTOR inhibition mimic MRT differentiation, which we confirm experimentally. Our study defines the developmental block of MRT and reveals potential differentiation therapies.
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http://dx.doi.org/10.1038/s41467-021-21675-6DOI Listing
March 2021

Tumor to normal single-cell mRNA comparisons reveal a pan-neuroblastoma cancer cell.

Sci Adv 2021 Feb 5;7(6). Epub 2021 Feb 5.

Wellcome Sanger Institute, CB10 1SA Hinxton, UK.

Neuroblastoma is a childhood cancer that resembles developmental stages of the neural crest. It is not established what developmental processes neuroblastoma cancer cells represent. Here, we sought to reveal the phenotype of neuroblastoma cancer cells by comparing cancer ( = 19,723) with normal fetal adrenal single-cell transcriptomes ( = 57,972). Our principal finding was that the neuroblastoma cancer cell resembled fetal sympathoblasts, but no other fetal adrenal cell type. The sympathoblastic state was a universal feature of neuroblastoma cells, transcending cell cluster diversity, individual patients, and clinical phenotypes. We substantiated our findings in 650 neuroblastoma bulk transcriptomes and by integrating canonical features of the neuroblastoma genome with transcriptional signals. Overall, our observations indicate that a pan-neuroblastoma cancer cell state exists, which may be attractive for novel immunotherapeutic and targeted avenues.
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http://dx.doi.org/10.1126/sciadv.abd3311DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7864567PMC
February 2021

Intratumoral IL-12 delivery empowers CAR-T cell immunotherapy in a pre-clinical model of glioblastoma.

Nat Commun 2021 01 19;12(1):444. Epub 2021 Jan 19.

Institute of Experimental Immunology, University of Zurich, 8057, Zurich, Switzerland.

Glioblastoma multiforme (GBM) is the most common and aggressive form of primary brain cancer, for which effective therapies are urgently needed. Chimeric antigen receptor (CAR)-based immunotherapy represents a promising therapeutic approach, but it is often impeded by highly immunosuppressive tumor microenvironments (TME). Here, in an immunocompetent, orthotopic GBM mouse model, we show that CAR-T cells targeting tumor-specific epidermal growth factor receptor variant III (EGFRvIII) alone fail to control fully established tumors but, when combined with a single, locally delivered dose of IL-12, achieve durable anti-tumor responses. IL-12 not only boosts cytotoxicity of CAR-T cells, but also reshapes the TME, driving increased infiltration of proinflammatory CD4 T cells, decreased numbers of regulatory T cells (Treg), and activation of the myeloid compartment. Importantly, the immunotherapy-enabling benefits of IL-12 are achieved with minimal systemic effects. Our findings thus show that local delivery of IL-12 may be an effective adjuvant for CAR-T cell therapy for GBM.
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http://dx.doi.org/10.1038/s41467-020-20599-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7815781PMC
January 2021

Antitumor activity without on-target off-tumor toxicity of GD2-chimeric antigen receptor T cells in patients with neuroblastoma.

Sci Transl Med 2020 11;12(571)

Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 1EH, UK.

The reprogramming of a patient's immune system through genetic modification of the T cell compartment with chimeric antigen receptors (CARs) has led to durable remissions in chemotherapy-refractory B cell cancers. Targeting of solid cancers by CAR-T cells is dependent on their infiltration and expansion within the tumor microenvironment, and thus far, fewer clinical responses have been reported. Here, we report a phase 1 study (NCT02761915) in which we treated 12 children with relapsed/refractory neuroblastoma with escalating doses of second-generation GD2-directed CAR-T cells and increasing intensity of preparative lymphodepletion. Overall, no patients had objective clinical response at the evaluation point +28 days after CAR-T cell infusion using standard radiological response criteria. However, of the six patients receiving ≥10/meter CAR-T cells after fludarabine/cyclophosphamide conditioning, two experienced grade 2 to 3 cytokine release syndrome, and three demonstrated regression of soft tissue and bone marrow disease. This clinical activity was achieved without on-target off-tumor toxicity. Targeting neuroblastoma with GD2 CAR-T cells appears to be a valid and safe strategy but requires further modification to promote CAR-T cell longevity.
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http://dx.doi.org/10.1126/scitranslmed.abd6169DOI Listing
November 2020

Pediatric pan-central nervous system tumor analysis of immune-cell infiltration identifies correlates of antitumor immunity.

Nat Commun 2020 08 28;11(1):4324. Epub 2020 Aug 28.

Wolfson Childhood Cancer Research Centre, Northern Institute for Cancer Research, Newcastle University, Newcastle Upon Tyne, UK.

Immune-therapy is an attractive alternative therapeutic approach for targeting central nervous system (CNS) tumors and the constituency of the Tumor Immune Microenvironment (TIME) likely to predict patient response. Here, we describe the TIME of >6000 primarily pediatric CNS tumors using a deconvolution approach (methylCIBERSORT). We produce and validate a custom reference signature defining 11 non-cancer cell types to estimate relative proportions of infiltration in a panCNS tumor cohort spanning 80 subtypes. We group patients into three broad immune clusters associated with CNS tumor types/subtypes. In cohorts of medulloblastomas (n = 2325), malignant rhabdoid tumors (n = 229) and pediatric high-grade gliomas (n = 401), we show significant associations with molecular subgroups/subtypes, mutations, and prognosis. We further identify tumor-specific immune clusters with phenotypic characteristics relevant to immunotherapy response (i.e. Cytolytic score, PDL1 expression). Our analysis provides an indication of the potential future therapeutic and prognostic possibilities of immuno-methylomic profiling in pediatric CNS tumor patients that may ultimately inform approach to immune-therapy.
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http://dx.doi.org/10.1038/s41467-020-18070-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7455736PMC
August 2020

Embryonal precursors of Wilms tumor.

Science 2019 12;366(6470):1247-1251

Wellcome Sanger Institute, Hinxton CB10 1SA, UK.

Adult cancers often arise from premalignant clonal expansions. Whether the same is true of childhood tumors has been unclear. To investigate whether Wilms tumor (nephroblastoma; a childhood kidney cancer) develops from a premalignant background, we examined the phylogenetic relationship between tumors and corresponding normal tissues. In 14 of 23 cases studied (61%), we found premalignant clonal expansions in morphologically normal kidney tissues that preceded tumor development. These clonal expansions were defined by somatic mutations shared between tumor and normal tissues but absent from blood cells. We also found hypermethylation of the locus, a known driver of Wilms tumor development, in 58% of the expansions. Phylogenetic analyses of bilateral tumors indicated that clonal expansions can evolve before the divergence of left and right kidney primordia. These findings reveal embryonal precursors from which unilateral and multifocal cancers develop.
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http://dx.doi.org/10.1126/science.aax1323DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914378PMC
December 2019

Establishment and phenotyping of neurosphere cultures from primary neuroblastoma samples.

F1000Res 2019 10;8:823. Epub 2019 Jun 10.

Cancer Section, DBC Programme, UCL Great Ormond Street Institute of Child Health, London, UK.

: Primary cell culture using serum free media supplemented with growth factors has been used in a number of cancers to propagate primary cells with stem like properties, which form as spherical cellular aggregates. : We systematically evaluated the capacity of freshly disaggregated neuroblastoma tumors to become established as neurospheres in stem cell media using a uniform protocol. 67 primary neuroblastoma samples from patients treated at a single institution were prospectively evaluated for their ability to become established in culture. Samples, either solid tissue or cells from surgical transit fluid both post chemotherapy and chemotherapy naïve, were evaluated from diagnostic needle biopsies or surgical resections. : Overall 37 neurosphere cultures were successfully established from 67 samples. In 11 out of 14 cases investigated by flow cytometry, uniform staining for neuroblastoma markers CD56 and GD2 was demonstrated in CD45 negative non-hemopoietic cells, confirming neuroblastoma origin. : We present a simple and reproducible approach for producing primary neurospheres from neuroblastoma samples, which provides a reliable resource for future work including genetic analysis, stem cell research and models for therapeutics.
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http://dx.doi.org/10.12688/f1000research.18209.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6611133PMC
June 2020

Highlights of Children with Cancer UK's Workshop on Drug Delivery in Paediatric Brain Tumours.

Ecancermedicalscience 2016 31;10:630. Epub 2016 Mar 31.

Royal Manchester Children's Hospital, Oxford Rd, Manchester M13 9WL.

The first Workshop on Drug Delivery in Paediatric Brain Tumours was hosted in London by the charity Children with Cancer UK. The goals of the workshop were to break down the barriers to treating central nervous system (CNS) tumours in children, leading to new collaborations and further innovations in this under-represented and emotive field. These barriers include the physical delivery challenges presented by the blood-brain barrier, the underpinning reasons for the intractability of CNS cancers, and the practical difficulties of delivering cancer treatment to the brains of children. Novel techniques for overcoming these problems were discussed, new models brought forth, and experiences compared.
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http://dx.doi.org/10.3332/ecancer.2016.630DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4817522PMC
April 2016

An Optimized GD2-Targeting Retroviral Cassette for More Potent and Safer Cellular Therapy of Neuroblastoma and Other Cancers.

PLoS One 2016 31;11(3):e0152196. Epub 2016 Mar 31.

Cancer Institute, University College London, London, United Kingdom.

Neuroblastoma is the commonest extra cranial solid cancer of childhood. Despite escalation of treatment regimens, a significant minority of patients die of their disease. Disialoganglioside (GD2) is consistently expressed at high-levels in neuroblastoma tumors, which have been targeted with some success using therapeutic monoclonal antibodies. GD2 is also expressed in a range of other cancer but with the exception of some peripheral nerves is largely absent from non-transformed tissues. Chimeric Antigen Receptors (CARs) are artificial type I proteins which graft the specificity of a monoclonal antibody onto a T-cell. Clinical data with early CAR designs directed against GD2 have shown some promise in Neuroblastoma. Here, we describe a GD2-targeting CAR retroviral cassette, which has been optimized for CAR T-cell persistence, efficacy and safety.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152196PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4816271PMC
August 2016

Fluorescence-guided development of a tricistronic vector encoding bimodal optical and nuclear genetic reporters for in vivo cellular imaging.

EJNMMI Res 2015 28;5:18. Epub 2015 Mar 28.

UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD UK.

Background: In vivo imaging using genetic reporters is a central supporting tool in the development of cell and gene therapies affording us the ability to selectively track the therapeutic indefinitely. Previous studies have demonstrated the utility of the human norepinephrine transporter (hNET) as a positron emission tomography/single photon emission computed tomography (PET/SPECT) genetic reporter for in vivo cellular imaging. Here, our aim was to extend on this work and construct a tricistronic vector with dual optical (firefly luciferase) and nuclear (hNET) in vivo imaging and ex vivo histochemical capabilities. Guiding this development, we describe how a fluorescent substrate for hNET, 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP(+)), can be used to optimise vector design and serve as an in vitro functional screen.

Methods: Vectors were designed to co-express a bright red-shifted firefly luciferase (FLuc), hNET and a small marker gene RQR8. Genes were co-expressed using 2A peptide linkage, and vectors were transduced into a T cell line, SupT1. Two vectors were constructed with different gene orientations; FLuc.2A.RQR8.2A.hNET and hNET.2A.FLuc.2A.RQR8. hNET function was assessed using ASP(+)-guided flow cytometry. In vivo cellular conspicuity was confirmed using sequential bioluminescence imaging (BLI) and SPECT imaging of transduced SupT1 cells injected into the flanks of mice.

Results: SupT1/FLuc.2A.RQR8.2A.hNET cells resulted in >4-fold higher ASP(+) uptake compared to SupT1/hNET.2A.FLuc.2A.RQR8, suggesting that 2A orientation effected hNET function. SupT1/FLuc.2A.RQR8.2A.hNET cells were readily visualised with both BLI and SPECT, demonstrating high signal to noise at 24 h post (123)I-meta-iodobenzylguanidine (MIBG) administration.

Conclusions: In this study, a pre-clinical tricistronic vector with flow cytometry, BLI, SPECT and histochemical capabilities was constructed, which can be widely applied in cell tracking studies supporting the development of cell therapies. The study further demonstrates that hNET function in engineered cells can be assessed using ASP(+)-guided flow cytometry in place of costly radiosubstrate methodologies. This fluorogenic approach is unique to the hNET PET/SPECT reporter and may prove valuable when screening large numbers of cell lines or vector/mutant constructs.
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http://dx.doi.org/10.1186/s13550-015-0097-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4385325PMC
April 2015

Fluorescence-guided development of a tricistronic vector encoding bimodal optical and nuclear genetic reporters for in vivo cellular imaging.

EJNMMI Res 2015 28;5:18. Epub 2015 Mar 28.

UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD UK.

Background: In vivo imaging using genetic reporters is a central supporting tool in the development of cell and gene therapies affording us the ability to selectively track the therapeutic indefinitely. Previous studies have demonstrated the utility of the human norepinephrine transporter (hNET) as a positron emission tomography/single photon emission computed tomography (PET/SPECT) genetic reporter for in vivo cellular imaging. Here, our aim was to extend on this work and construct a tricistronic vector with dual optical (firefly luciferase) and nuclear (hNET) in vivo imaging and ex vivo histochemical capabilities. Guiding this development, we describe how a fluorescent substrate for hNET, 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP(+)), can be used to optimise vector design and serve as an in vitro functional screen.

Methods: Vectors were designed to co-express a bright red-shifted firefly luciferase (FLuc), hNET and a small marker gene RQR8. Genes were co-expressed using 2A peptide linkage, and vectors were transduced into a T cell line, SupT1. Two vectors were constructed with different gene orientations; FLuc.2A.RQR8.2A.hNET and hNET.2A.FLuc.2A.RQR8. hNET function was assessed using ASP(+)-guided flow cytometry. In vivo cellular conspicuity was confirmed using sequential bioluminescence imaging (BLI) and SPECT imaging of transduced SupT1 cells injected into the flanks of mice.

Results: SupT1/FLuc.2A.RQR8.2A.hNET cells resulted in >4-fold higher ASP(+) uptake compared to SupT1/hNET.2A.FLuc.2A.RQR8, suggesting that 2A orientation effected hNET function. SupT1/FLuc.2A.RQR8.2A.hNET cells were readily visualised with both BLI and SPECT, demonstrating high signal to noise at 24 h post (123)I-meta-iodobenzylguanidine (MIBG) administration.

Conclusions: In this study, a pre-clinical tricistronic vector with flow cytometry, BLI, SPECT and histochemical capabilities was constructed, which can be widely applied in cell tracking studies supporting the development of cell therapies. The study further demonstrates that hNET function in engineered cells can be assessed using ASP(+)-guided flow cytometry in place of costly radiosubstrate methodologies. This fluorogenic approach is unique to the hNET PET/SPECT reporter and may prove valuable when screening large numbers of cell lines or vector/mutant constructs.
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http://dx.doi.org/10.1186/s13550-015-0097-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4385325PMC
April 2015

Inducible apoptosis as a safety switch for adoptive cell therapy.

N Engl J Med 2011 Nov;365(18):1673-83

Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA.

Background: Cellular therapies could play a role in cancer treatment and regenerative medicine if it were possible to quickly eliminate the infused cells in case of adverse events. We devised an inducible T-cell safety switch that is based on the fusion of human caspase 9 to a modified human FK-binding protein, allowing conditional dimerization. When exposed to a synthetic dimerizing drug, the inducible caspase 9 (iCasp9) becomes activated and leads to the rapid death of cells expressing this construct.

Methods: We tested the activity of our safety switch by introducing the gene into donor T cells given to enhance immune reconstitution in recipients of haploidentical stem-cell transplants. Patients received AP1903, an otherwise bioinert small-molecule dimerizing drug, if graft-versus-host disease (GVHD) developed. We measured the effects of AP1903 on GVHD and on the function and persistence of the cells containing the iCasp9 safety switch.

Results: Five patients between the ages of 3 and 17 years who had undergone stem-cell transplantation for relapsed acute leukemia were treated with the genetically modified T cells. The cells were detected in peripheral blood from all five patients and increased in number over time, despite their constitutive transgene expression. A single dose of dimerizing drug, given to four patients in whom GVHD developed, eliminated more than 90% of the modified T cells within 30 minutes after administration and ended the GVHD without recurrence.

Conclusions: The iCasp9 cell-suicide system may increase the safety of cellular therapies and expand their clinical applications. (Funded by the National Heart, Lung, and Blood Institute and the National Cancer Institute; ClinicalTrials.gov number, NCT00710892.).
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http://dx.doi.org/10.1056/NEJMoa1106152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3236370PMC
November 2011

Adoptive transfer of EBV-specific T cells results in sustained clinical responses in patients with locoregional nasopharyngeal carcinoma.

J Immunother 2010 Nov-Dec;33(9):983-90

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas 77030, USA.

Patients with recurrent or refractory Epstein Barr Virus (EBV)-positive nasopharyngeal carcinoma (NPC) continue to have poor outcomes. Our earlier Phase I dose escalation clinical study of 10 NPC patients showed that infusion of EBV-specific cytotoxic T cells (EBV-CTLs) was safe and had antitumor activity. To better define the overall response rate and discover whether disease status, EBV-antigen specificity, and/or in vivo expansion of infused EBV-CTLs predicted outcome, we treated 13 additional NPC patients with EBV-CTLs in a fixed-dose, Phase II component of the study. We assessed toxicity, efficacy, specificity, and expansion of infused CTLs for all 23 recurrent/refractory NPC patients treated on this Phase I/II clinical study. At the time of CTL infusion, 8 relapsed NPC patients were in remission and 15 had active disease. No significant toxicity was observed. Of the relapsed patients treated in their second or subsequent remission, 62% (5/8) remain disease free (at 17 to 75 mo), whereas 48.7% (7/15) of those with active disease had a CR/CRu (33.3%) or PR (15.4%). In contrast to locoregional disease, metastatic disease was associated with an increased risk of disease progression (HR: 3.91, P=0.015) and decreased overall survival (HR: 5.55, P=0.022). Neither the specificity of the infused CTLs for particular EBV antigens nor their measurable in vivo expansion discernibly influenced outcome. In conclusion, treatment of patients with relapsed/refractory EBV-positive NPC with EBV-CTLs is safe and can be associated with significant, long-term clinical benefit, particularly for patients with locoregional disease.
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http://dx.doi.org/10.1097/CJI.0b013e3181f3cbf4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2964409PMC
May 2011

Generation of EBV-specific cytotoxic T cells that are resistant to calcineurin inhibitors for the treatment of posttransplantation lymphoproliferative disease.

Blood 2009 Nov 21;114(23):4792-803. Epub 2009 Sep 21.

Molecular Immunology Unit, Institute of Child Health, University College London, London, United Kingdom.

Epstein-Barr virus (EBV)-driven posttransplantation lymphoproliferative disease (PTLD) is a serious complication of immunosuppression after either stem cell transplantation (SCT) or solid organ transplantation (SOT). Adoptive transfer of EBV-specific cytotoxic T lymphocytes (EBV-CTLs) is an effective prophylaxis and treatment for PTLD after SCT, but not for PTLD after SOT when pharmacologic immunosuppression cannot be discontinued. We report the generation of calcineurin (CN) mutants that render EBV-CTL resistant to the immunosuppressants tacrolimus (FK506) and cyclosporin A (CsA): mutant CNa12 confers resistance to CsA but not FK506, and mutant CNa22 confers resistance to FK506 but not CsA, whereas mutant CNb30 renders CTLs resistant to both calcineurin inhibitors. Untransduced EBV-CTLs do not proliferate in the presence of FK506/CsA. However, EBV-CTLs transduced with a retroviral vector coding for these mutants retain the ability to both proliferate and secrete normal levels of interferon-gamma in the presence therapeutic levels of FK506 (CNa12), CsA (CNa22), or both (CNb30). The cytotoxicity and phenotype of EBV-CTL lines were unaffected by expression of these mutant CNs. This approach should allow effective immunotherapy with EBV-CTLs in the SOT setting without risking the graft by reduction in immunosuppression, and represents a generic approach to improving immunotherapy in the face of immunosuppression.
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http://dx.doi.org/10.1182/blood-2009-07-228387DOI Listing
November 2009

Haemopoietic stem-cell transplantation with antibody-based minimal-intensity conditioning: a phase 1/2 study.

Lancet 2009 Sep 2;374(9693):912-20. Epub 2009 Sep 2.

Great Ormond Street Children's Hospital, London, UK.

Background: Stem-cell transplantation can cure primary immunodeficiencies. However, in patients with pre-existing organ toxicity, patients younger than 1 year, and those with DNA or telomere repair disorders, chemotherapy-based conditioning is poorly tolerated and results in major morbidity and mortality. We tested a novel antibody-based minimal-intensity conditioning (MIC) regimen to assess whether this approach allowed curative donor stem-cell engraftment without non-haemopoietic toxicity.

Methods: 16 high-risk patients underwent stem-cell transplantation for primary immunodeficiencies with an MIC regimen consisting of two rat anti-CD45 monoclonal antibodies YTH 24.5 and YTH 54.12 for myelosuppression, and alemtuzumab (anti-CD52) and fludarabine, and low dose cyclophosphamide for immunosuppression. Donors were matched siblings (n=5), and matched (9) and mismatched (2) unrelated donors.

Findings: Antibody-based conditioning was well tolerated, with only two cases of grade 3 and no grade 4 toxicity. Rates of clinically significant acute (n=6, 36%) and chronic graft-versus-host disease (GVHD) (n=5, 31%) were acceptable. 15 of 16 patients (94%) engrafted, of whom 11 (69%) achieved full or high-level mixed chimerism in both lymphoid and myeloid lineages, and three achieved engraftment in the T-lymphoid lineage only. One patient needed retransplantation. At a median of 40 months post-transplant, 13 of 16 patients (81%) in this high-risk cohort were alive and cured from their underlying disease.

Interpretation: Monoclonal antibody-based conditioning seems well tolerated and can achieve curative engraftment even in patients with severe organ toxicity or DNA repair defects, or both. This novel approach represents a shift from the paradigm that intensive chemotherapy or radiotherapy, or both, is needed for donor stem-cell engraftment. This antibody-based conditioning regimen may reduce toxicity and late effects and enable SCT in virtually any primary immunodeficiency patient with a matched donor.

Funding: None.
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http://dx.doi.org/10.1016/S0140-6736(09)60945-4DOI Listing
September 2009

Enhancing the in vivo expansion of adoptively transferred EBV-specific CTL with lymphodepleting CD45 monoclonal antibodies in NPC patients.

Blood 2009 Mar 29;113(11):2442-50. Epub 2008 Oct 29.

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA.

Treatment of Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC) with EBV-specific cytotoxic T cells (EBV-specific CTL) has been promising, producing clinical responses. However, infused EBV-specific CTL did not expand in vivo, likely limiting their antitumor activity. Lymphodepleting patients with chemotherapy before T-cell transfer enhances in vivo T-cell expansion, but results in nonspecific destruction of the resident immune system and can have significant toxicity. To evaluate if monoclonal antibodies (mAbs) can produce a more selective lymphodepletion, we conducted a clinical study in which NPC patients received a pair of lymphodepleting mAbs targeted to the CD45 antigen (CD45 mAbs) before EBV-specific CTL infusion. Eight patients with recurrent NPC received CD45 mAbs followed by escalating doses of autologous EBV-specific CTL. Infusion of CD45 mAbs resulted in transient lymphopenia in all patients and an increase in interleukin-15 (IL-15) levels in 6 out 8 patients. All patients had an increase in their peripheral blood frequency of EBV-specific T cells after CTL infusion. Three patients with a persistent increase had clinical benefits including 1 complete response (> 24 months) and 2 with stable disease (for 12 and 15 months). Lymphodepleting mAbs prior CTL transfer may represent an alternative to chemotherapy to enhance expansion of infused CTL. This study is registered at (http://www.clinialtrials.gov) as NCT00608257.
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http://dx.doi.org/10.1182/blood-2008-05-157222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2656271PMC
March 2009

An inducible caspase 9 safety switch can halt cell therapy-induced autoimmune disease.

J Immunol 2008 May;180(9):6365-73

Division of Immunology, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, The Netherlands.

Transfer of either allogeneic or genetically modified T cells as a therapy for malignancies can be accompanied by T cell-mediated tissue destruction. The introduction of an efficient "safety switch" can potentially be used to control the survival of adoptively transferred cell populations and as such reduce the risk of severe graft-vs-host disease. In this study, we have tested the value of an inducible caspase 9-based safety switch to halt an ongoing immune attack in a murine model for cell therapy-induced type I diabetes. The data obtained in this model indicate that self-reactive T cells expressing this conditional safety switch show unimpaired lymphopenia- and vaccine-induced proliferation and effector function in vivo, but can be specifically and rapidly eliminated upon triggering. These data provide strong support for the evaluation of this conditional safety switch in clinical trials of adoptive cell therapy.
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http://dx.doi.org/10.4049/jimmunol.180.9.6365DOI Listing
May 2008

Complete responses of relapsed lymphoma following genetic modification of tumor-antigen presenting cells and T-lymphocyte transfer.

Blood 2007 Oct 3;110(8):2838-45. Epub 2007 Jul 3.

Center for Cell and Gene Therapy, Baylor College of Medicine, The Methodist Hospital and Texas Children's Hospital, Houston, TX 77030, USA.

Epstein-Barr virus (EBV)-associated tumors developing in immunocompetent individuals present a challenge to immunotherapy, since they lack expression of immunodominant viral antigens. However, the tumors consistently express viral proteins including LMP2, which are immunologically "weak" but may nonetheless be targets for immune T cells. We previously showed that a majority of cytotoxic T lymphocytes (CTLs) reactivated using EBV-transformed B-lymphoblastoid cells lines (LCLs) contained minor populations of LMP2-specific T cells and homed to tumor sites. However, they did not produce remissions in patients with bulky disease. We have now used gene transfer into antigen-presenting cells (APCs) to augment the expression and immunogenicity of LMP2. These modified APCs increased the frequency of LMP2-specific CTLs by up to 100-fold compared with unmodified LCL-APCs. The LMP2-specific population expanded and persisted in vivo without adverse effects. Nine of 10 patients treated in remission of high-risk disease remain in remission, and 5 of 6 patients with active relapsed disease had a tumor response, which was complete in 4 and sustained for more than 9 months. It is therefore possible to generate immune responses to weak tumor antigens by ex vivo genetic modification of APCs and the CTLs so produced can have substantial antitumor activity. This study is registered at http://www.cancer.gov/clinicaltrials (protocol IDs: BCM-H-9936, NCT00062868, NCT00070226).
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http://dx.doi.org/10.1182/blood-2007-05-091280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2018666PMC
October 2007

Characterization of latent membrane protein 2 specificity in CTL lines from patients with EBV-positive nasopharyngeal carcinoma and lymphoma.

J Immunol 2005 Sep;175(6):4137-47

Center for Cell and Gene Therapy, Baylor College of Medicine, Methodist Hospital and Texas Children's Hospital, Houston, TX 77030, USA.

Viral proteins expressed by EBV-associated tumors provide target Ags for immunotherapy. Adoptive T cell therapy has proven effective for posttransplant EBV-associated lymphoma in which all EBV latent Ags are expressed (type III latency). Application of immunotherapeutic strategies to tumors such as nasopharyngeal carcinoma and Hodgkin's lymphoma that have a restricted pattern of EBV Ag expression (type II latency) is under investigation. Potential EBV Ag targets for T cell therapy expressed by these tumors include latent membrane proteins (LMP) 1 and 2. A broad panel of epitopes must be identified from these target Ags to optimize vaccination strategies and facilitate monitoring of tumor-specific T cell populations after immunotherapeutic interventions. To date, LMP2 epitopes have been identified for only a limited number of HLA alleles. Using a peptide library spanning the entire LMP2 sequence, 25 CTL lines from patients with EBV-positive malignancies expressing type II latency were screened for the presence of LMP2-specific T cell populations. In 21 of 25 lines, T cell responses against one to five LMP2 epitopes were identified. These included responses to previously described epitopes as well as to newly identified HLA-A*0206-, A*0204/17-, A29-, A68-, B*1402-, B27-, B*3501-, B53-, and HLA-DR-restricted epitopes. Seven of the nine newly identified epitopes were antigenically conserved among virus isolates from nasopharyngeal carcinoma tumors. These new LMP2 epitopes broaden the diversity of HLA alleles with available epitopes, and, in particular, those epitopes conserved between EBV strains provide valuable tools for immunotherapy and immune monitoring.
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http://dx.doi.org/10.4049/jimmunol.175.6.4137DOI Listing
September 2005

A chimeric T cell antigen receptor that augments cytokine release and supports clonal expansion of primary human T cells.

Mol Ther 2005 Nov 23;12(5):933-41. Epub 2005 Jun 23.

Center for Cell and Gene Therapy, Baylor College of Medicine, 6621 Fannin MC3-3320, Houston, TX 77030, USA.

The transduction of primary T cells to express chimeric T cell receptors (cTCR) for redirected targeting of tumor cells is an attractive strategy for generating tumor-specific T cells for adoptive therapy. However, tumor cells rarely provide costimulatory signals and hence cTCRs that transmit just a CD3zeta signal can only initiate target cell killing and interferon-gamma release and fail to induce full activation. Although incorporation of a CD28 component results in IL-2 release and limited proliferation, T cell activation remains incomplete. OX40 transmits a potent and prolonged T cell activation signal and is crucial for maintaining an immunological response. We hypothesize that the CD28-OX40-CD3zeta tripartite cytoplasmic domain will provide a full complement of activation, proliferation, and survival signals for enhanced anti-tumor activity.
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http://dx.doi.org/10.1016/j.ymthe.2005.04.016DOI Listing
November 2005

An inducible caspase 9 safety switch for T-cell therapy.

Blood 2005 Jun 22;105(11):4247-54. Epub 2005 Feb 22.

Center for Cell and Gene Therapy, Baylor College of Meidcine, Houston, TX 77030, USA.

The efficacy of adoptive T-cell therapy as treatment for malignancies may be enhanced by genetic modification of infused cells. However, oncogenic events due to vector/transgene integration, and toxicities due to the infused cells themselves, have tempered enthusiasm. A safe and efficient means of removing aberrant cells in vivo would ameliorate these concerns. We describe a "safety switch" that can be stably and efficiently expressed in human T cells without impairing phenotype, function, or antigen specificity. This reagent is based on a modified human caspase 9 fused to a human FK506 binding protein (FKBP) to allow conditional dimerization using a small molecule pharmaceutical. A single 10-nM dose of synthetic dimerizer drug induces apoptosis in 99% of transduced cells selected for high transgene expression in vitro and in vivo. This system has several advantages over currently available suicide genes. First, it consists of human gene products with low potential immunogenicity. Second, administration of dimerizer drug has no effects other than the selective elimination of transduced T cells. Third, inducible caspase 9 maintains function in T cells overexpressing antiapoptotic molecules. These characteristics favor incorporation of inducible caspase 9 as a safety feature in human T-cell therapies.
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http://dx.doi.org/10.1182/blood-2004-11-4564DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1895037PMC
June 2005

Human cytotoxic T lymphocytes with reduced sensitivity to Fas-induced apoptosis.

Blood 2005 Jun 15;105(12):4677-84. Epub 2005 Feb 15.

Center for Cell and Gene Therapy, Baylor College of Medicine, 6621 Fannin St, MC 3-3320, Houston, TX 77030, USA.

Effector-memory T cells expressing Fas (Apo-1/CD95) are switched to an apoptotic program by cross-linking with Fas-ligand (FasL). Consequently, tumors that express FasL can induce apoptosis of infiltrating Fas-positive T lymphocytes and subdue any antitumor host immune response. Since Epstein-Barr virus (EBV)-associated tumors such as Hodgkin lymphoma (HL) and nasopharyngeal carcinoma (NPC) express FasL, we determined whether EBV-specific cytotoxic T lymphocytes (EBV-CTLs) could be modified to resist this evasion strategy. We show that long-term down-modulation of Fas can be achieved in EBV-CTLs by transduction with small interfering RNA (siRNA) encoded in a retrovirus. Modified T cells resisted Fas/FasL-mediated apoptosis compared with control cells and showed minimal cleavage of the caspase3 substrate poly(ADP-ribose) polymerase (PARP) protein after Fas engagement. Prolonged Fas stimulation selected a uniformly Fas(low) and FasL resistant population. Removal of responsiveness to this single death signal had no other discernible effects on EBV-CTLs. In particular, it did not lead to their autonomous growth since the modified EBV-CTLs remained polyclonal, and their survival and proliferation retained dependence on antigen-specific stimulation and on the presence of other physiologic growth signals. EBV-CTLs with knocked down Fas should have a selective functional and survival advantage over unmodified EBV-CTLs in the presence of tumors expressing FasL and may be of value for adoptive cellular therapy.
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http://dx.doi.org/10.1182/blood-2004-08-3337DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1895003PMC
June 2005

Cytotoxic T lymphocyte therapy for Epstein-Barr virus+ Hodgkin's disease.

J Exp Med 2004 Dec;200(12):1623-33

Center for Gene and Cell Therapy, Baylor College of Medicine, 6621 Fannin St., MC 3-3320, Houston, TX 77030, USA.

Epstein Barr virus (EBV)+ Hodgkin's disease (HD) expresses clearly identified tumor antigens derived from the virus and could, in principle, be a target for adoptive immunotherapy with viral antigen-specific T cells. However, like most tumor-associated antigens in immunocompetent hosts, these potential targets are only weakly immunogenic, consisting primarily of the latent membrane protein (LMP)1 and LMP2 antigens. Moreover, Hodgkin tumors possess a range of tumor evasion strategies. Therefore, the likely value of immunotherapy with EBV-specific cytotoxic effector cells has been questioned. We have now used a combination of gene marking, tetramer, and functional analyses to track the fate and assess the activity of EBV cytotoxic T lymphocyte (CTL) lines administered to 14 patients treated for relapsed EBV+ HD. Gene marking studies showed that infused effector cells could further expand by several logs in vivo, contribute to the memory pool (persisting up to 12 mo), and traffic to tumor sites. Tetramer and functional analyses showed that T cells reactive with the tumor-associated antigen LMP2 were present in the infused lines, expanded in peripheral blood after infusion, and also entered tumor. Viral load decreased, demonstrating the biologic activity of the infused CTLs. Clinically, EBV CTLs were well tolerated, could control type B symptoms (fever, night sweats, and weight loss), and had antitumor activity. After CTL infusion, five patients were in complete remission at up to 40 mo, two of whom had clearly measurable tumor at the time of treatment. One additional patient had a partial response, and five had stable disease. The performance and fate of these human tumor antigen-specific T cells in vivo suggests that they might be of value for the treatment of EBV+ Hodgkin lymphoma.
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http://dx.doi.org/10.1084/jem.20040890DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2211993PMC
December 2004

Treatment of nasopharyngeal carcinoma with Epstein-Barr virus--specific T lymphocytes.

Blood 2005 Mar 12;105(5):1898-904. Epub 2004 Nov 12.

Center for Cell and Gene Therapy, Department of Pediatrics, Baylor College of Medicine, 1102 Bates St, Suite 1120, Houston, TX 77030, USA.

Conventional treatment for nasopharyngeal carcinoma (NPC) frequently fails and is accompanied by severe long-term side effects. Since virtually all undifferentiated NPCs are associated with Epstein-Barr virus (EBV), this tumor is an attractive candidate for cellular immunotherapy targeted against tumor-associated viral antigens. We now demonstrate that EBV-specific cytotoxic T-cell (CTL) lines can readily be generated from individuals with NPC, notwithstanding the patients' prior exposure to chemotherapy/radiation. A total of 10 patients diagnosed with advanced NPC were treated with autologous CTLs. All patients tolerated the CTLs, although one developed increased swelling at the site of pre-existing disease. At 19 to 27 months after infusion, 4 patients treated in remission from locally advanced disease remain disease free. Of 6 patients with refractory disease prior to treatment, 2 had complete responses, and remain in remission over 11 to 23 months after treatment; 1 had a partial remission that persisted for 12 months; 1 has had stable disease for more than 14 months; and 2 had no response. These results demonstrate that administration of EBV-specific CTLs to patients with advanced NPC is feasible, appears to be safe, and can be associated with significant antitumor activity.
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http://dx.doi.org/10.1182/blood-2004-07-2975DOI Listing
March 2005

The generation and characterization of LMP2-specific CTLs for use as adoptive transfer from patients with relapsed EBV-positive Hodgkin disease.

J Immunother 2004 Jul-Aug;27(4):317-27

Center for Cell and Gene Therapy, Baylor College of Medicine, The Methodist Hospital and Texas Children's Hospital, Houston, Texas 77030, USA.

Cellular adoptive immunotherapy for virus-associated malignant disease is an attractive strategy, since viral antigens provide targets for specific T lymphocytes. In Epstein-Barr virus (EBV)-positive Hodgkin disease (HD), a limited number of EBV-encoded antigens such as the latent membrane antigens (LMP) 1 and 2 are expressed on the malignant Reed-Sternberg cells. The authors aimed to generate cytotoxic T lymphocytes (CTLs) from patients with relapsed HD by specifically targeting LMP2A. Patients with relapsed HD have highly immunosuppressive tumors and have been heavily pretreated with cytotoxic agents. As a result, monocytes and lymphocytes are numerically reduced and functionally impaired. Approaches using dendritic cells (DCs) as the sole antigen-presenting cell to expand LMP2-specific CTL lines in vitro have proved impractical. The authors now show how small amounts of patient peripheral blood can be used to produce DCs expressing LMP2 after Ad5F35 transduction, and how an initial reactivation of LMP2-specific CTLs can be followed by stimulation with lymphoblastoid cell lines overexpressing LMP2 from the same vector. Large numbers of LMP2-specific cytotoxic lymphocytes are produced that contain both CD4+ and CD8+ T cells (favoring long-term persistence in vivo) and recognize multiple LMP2 epitopes (minimizing the risk of tumor antigen loss variants). This approach is being used in a current clinical trial.
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http://dx.doi.org/10.1097/00002371-200407000-00008DOI Listing
March 2005

Immunotherapy for Epstein-Barr virus-associated cancers in children.

Oncologist 2003 ;8(1):83-98

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas 77030, USA.

Latent Epstein-Barr virus (EBV) infection is associated with several malignancies, including Burkitt's lymphoma, Hodgkin's disease, nasopharyngeal carcinoma, and post-transplant lymphoproliferative disease (LPD). The presence of EBV antigens in these tumors provides a target for immunotherapy approaches, and immunotherapy with EBV-specific cytotoxic T cells (CTLs) has proved effective in post-transplant LPDs, which are highly immunogenic tumors expressing type III latency. The malignant cells in Hodgkin's disease and nasopharyngeal carcinoma express type II latency and hence a more restricted pattern of EBV antigens. Trials with autologous EBV-specific CTL responses are under way in both of these diseases, and while some activity has been seen, no patient has yet been cured. This reduced CTL efficacy may reflect either downregulation of immunodominant EBV proteins, which are major CTL targets, or the ability of these tumors to evade the immune response by secreting inhibitory cytokines. Further improvement of EBV-specific CTL therapy for these type II latency tumors will require improved methods to activate and expand CTLs specific for the subdominant EBV genes expressed and to genetically modify the expanded CTLs to render them resistant to inhibitory cytokines. If these strategies to improve the therapeutic potential of immunotherapy for EBV-associated tumors prove successful, this type of treatment may be adapted to other tumors expressing known (viral) antigens.
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http://dx.doi.org/10.1634/theoncologist.8-1-83DOI Listing
May 2003

Immunotherapy for post-transplant lymphoproliferative disease.

Br J Haematol 2002 Sep;118(3):728-40

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA.

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http://dx.doi.org/10.1046/j.1365-2141.2002.03594.xDOI Listing
September 2002