scholarly journals Co-Expression of miR155 or LSD1 shRNA Increases the Anti-Tumor Functions of CD19 CAR-T Cells

2022 ◽  
Vol 12 ◽  
Author(s):  
Jing Zhang ◽  
Jingjing Zhu ◽  
Genhui Zheng ◽  
Qianyu Wang ◽  
Xiaorui Li ◽  
...  
Keyword(s):  
T Cells ◽  
Transcriptional Profiling ◽  
Retroviral Vectors ◽  
Shrna Expression ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Novel Approach ◽  
Car T

Chimeric antigen receptor (CAR) T cells targeting CD19 antigen have produced remarkable clinical outcomes for cancer patients. However, identifying measures to enhance effector function remains one of the most challenging issues in CD19-targeted immunotherapy. Here, we report a novel approach in which a microRNA (miRNA) or short-hairpin RNA (shRNA) cassette was integrated into CAR-expressing retroviral vectors. Using this system, we generated anti-CD19 CAR-T cells co-expressing miR155 or LSD1 shRNA and found that anti-CD19 CAR-T cells with miR155 upregulation or LSD1 downregulation exhibited increased anti-tumor functions in vitro and in vivo. Transcriptional profiling analysis by RNA sequencing revealed the targets of miR155 and LSD1 in anti-CD19 CAR-T cells. Our experiments indicated that introduction of miRNA or shRNA expression into anti-CD19 CAR T-cells might be an effective strategy to improve the anti-tumor effects of CAR-T cell therapy.

98 ATA3271: an armored, next-generation off-the-shelf, allogeneic, mesothelin-CAR T cell therapy for solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A109-A109
Author(s):  
Jiangyue Liu ◽  
Xianhui Chen ◽  
Jason Karlen ◽  
Alfonso Brito ◽  
Tiffany Jheng ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Next Generation ◽  
Phase 3 ◽  
T Cell Therapy ◽  
Cell Therapies ◽  
Car T Cells ◽  
Car T

BackgroundMesothelin (MSLN) is a glycosylphosphatidylinositol (GPI)-anchored membrane protein with high expression levels in an array of malignancies including mesothelioma, ovaria, non-small cell lung cancer, and pancreatic cancers and is an attractive target antigen for immune-based therapies. Early clinical evaluation of autologous MSLN-targeted chimeric antigen receptor (CAR)-T cell therapies for malignant pleural mesothelioma has shown promising acceptable safety1 and have recently evolved with incorporation of next-generation CAR co-stimulatory domains and armoring with intrinsic checkpoint inhibition via expression of a PD-1 dominant negative receptor (PD1DNR).2 Despite the promise that MSLN CAR-T therapies hold, manufacturing and commercial challenges using an autologous approach may prove difficult for widespread application. EBV T cells represent a unique, non-gene edited approach toward an off-the-shelf, allogeneic T cell platform. EBV-specific T cells are currently being evaluated in phase 3 trials [NCT03394365] and, to-date, have demonstrated a favorable safety profile including limited risks for GvHD and cytokine release syndrome.3 4 Clinical proof-of-principle studies for CAR transduced allogeneic EBV T cell therapies have also been associated with acceptable safety and durable response in association with CD19 targeting.5 Here we describe the first preclinical evaluation of ATA3271, a next-generation allogeneic CAR EBV T cell therapy targeting MSLN and incorporating PD1DNR, designed for the treatment of solid tumor indications.MethodsWe generated allogeneic MSLN CAR+ EBV T cells (ATA3271) using retroviral transduction of EBV T cells. ATA3271 includes a novel 1XX CAR signaling domain, previously associated with improved signaling and decreased CAR-mediated exhaustion. It is also armored with PD1DNR to provide intrinsic checkpoint blockade and is designed to retain functional persistence.ResultsIn this study, we characterized ATA3271 both in vitro and in vivo. ATA3271 show stable and proportional CAR and PD1DNR expression. Functional studies show potent antitumor activity of ATA3271 against MSLN-expressing cell lines, including PD-L1-high expressors. In an orthotopic mouse model of pleural mesothelioma, ATA3271 demonstrates potent antitumor activity and significant survival benefit (100% survival exceeding 50 days vs. 25 day median for control), without evident toxicities. ATA3271 maintains persistence and retains central memory phenotype in vivo through end-of-study. Additionally, ATA3271 retains endogenous EBV TCR function and reduced allotoxicity in the context of HLA mismatched targets. ConclusionsOverall, ATA3271 shows potent anti-tumor activity without evidence of allotoxicity, both in vitro and in vivo, suggesting that allogeneic MSLN-CAR-engineered EBV T cells are a promising approach for the treatment of MSLN-positive cancers and warrant further clinical investigation.ReferencesAdusumilli PS, Zauderer MG, Rusch VW, et al. Abstract CT036: A phase I clinical trial of malignant pleural disease treated with regionally delivered autologous mesothelin-targeted CAR T cells: Safety and efficacy. Cancer Research 2019;79:CT036-CT036.Kiesgen S, Linot C, Quach HT, et al. Abstract LB-378: Regional delivery of clinical-grade mesothelin-targeted CAR T cells with cell-intrinsic PD-1 checkpoint blockade: Translation to a phase I trial. Cancer Research 2020;80:LB-378-LB-378.Prockop S, Doubrovina E, Suser S, et al. Off-the-shelf EBV-specific T cell immunotherapy for rituximab-refractory EBV-associated lymphoma following transplantation. J Clin Invest 2020;130:733–747.Prockop S, Hiremath M, Ye W, et al. A Multicenter, Open Label, Phase 3 Study of Tabelecleucel for Solid Organ Transplant Subjects with Epstein-Barr Virus-Driven Post-Transplant Lymphoproliferative Disease (EBV+PTLD) after Failure of Rituximab or Rituximab and Chemotherapy. Blood 2019; 134: 5326–5326.Curran KJ, Sauter CS, Kernan NA, et al. Durable remission following ‘Off-the-Shelf’ chimeric antigen receptor (CAR) T-Cells in patients with relapse/refractory (R/R) B-Cell malignancies. Biology of Blood and Marrow Transplantation 2020;26:S89.

scholarly journals 124 Functionalizing CAR T cells for selective proliferation and dual-targeting using the meditope technology

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A133-A133
Author(s):  
Cheng-Fu Kuo ◽  
Yi-Chiu Kuo ◽  
Miso Park ◽  
Zhen Tong ◽  
Brenda Aguilar ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

BackgroundMeditope is a small cyclic peptide that was identified to bind to cetuximab within the Fab region. The meditope binding site can be grafted onto any Fab framework, creating a platform to uniquely and specifically target monoclonal antibodies. Here we demonstrate that the meditope binding site can be grafted onto chimeric antigen receptors (CARs) and utilized to regulate and extend CAR T cell function. We demonstrate that the platform can be used to overcome key barriers to CAR T cell therapy, including T cell exhaustion and antigen escape.MethodsMeditope-enabled CARs (meCARs) were generated by amino acid substitutions to create binding sites for meditope peptide (meP) within the Fab tumor targeting domain of the CAR. meCAR expression was validated by anti-Fc FITC or meP-Alexa 647 probes. In vitro and in vivo assays were performed and compared to standard scFv CAR T cells. For meCAR T cell proliferation and dual-targeting assays, the meditope peptide (meP) was conjugated to recombinant human IL15 fused to the CD215 sushi domain (meP-IL15:sushi) and anti-CD20 monoclonal antibody rituximab (meP-rituximab).ResultsWe generated meCAR T cells targeting HER2, CD19 and HER1/3 and demonstrate the selective specific binding of the meditope peptide along with potent meCAR T cell effector function. We next demonstrated the utility of a meP-IL15:sushi for enhancing meCAR T cell proliferation in vitro and in vivo. Proliferation and persistence of meCAR T cells was dose dependent, establishing the ability to regulate CAR T cell expansion using the meditope platform. We also demonstrate the ability to redirect meCAR T cells tumor killing using meP-antibody adaptors. As proof-of-concept, meHER2-CAR T cells were redirected to target CD20+ Raji tumors, establishing the potential of the meditope platform to alter the CAR specificity and overcome tumor heterogeneity.ConclusionsOur studies show the utility of the meCAR platform for overcoming key challenges for CAR T cell therapy by specifically regulating CAR T cell functionality. Specifically, the meP-IL15:sushi enhanced meCAR T cell persistence and proliferation following adoptive transfer in vivo and protects against T cell exhaustion. Further, meP-ritiuximab can redirect meCAR T cells to target CD20-tumors, showing the versatility of this platform to address the tumor antigen escape variants. Future studies are focused on conferring additional ‘add-on’ functionalities to meCAR T cells to potentiate the therapeutic effectiveness of CAR T cell therapy.

scholarly journals Targeting glycosylation of PD-1 to enhance CAR-T cell cytotoxicity

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaojuan Shi ◽  
Daiqun Zhang ◽  
Feng Li ◽  
Zhen Zhang ◽  
Shumin Wang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Inhibitory Effects ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

AbstractAsparagine-linked (N-linked) glycosylation is ubiquitous and can stabilize immune inhibitory PD-1 protein. Reducing N-linked glycosylation of PD-1 may decrease PD-1 expression and relieve its inhibitory effects on CAR-T cells. Considering that the codon of Asparagine is aac or aat, we wondered if the adenine base editor (ABE), which induces a·t to g·c conversion at specific site, could be used to reduce PD-1 suppression by changing the glycosylated residue in CAR-T cells. Our results showed ABE editing altered the coding sequence of N74 residue of PDCD1 and downregulated PD-1 expression in CAR-T cells. Further analysis showed ABE-edited CAR-T cells had enhanced cytotoxic functions in vitro and in vivo. Our study suggested that the single base editors can be used to augment CAR-T cell therapy.

scholarly journals Efficient elimination of primary B-ALL cells in vitro and in vivo using a novel 4-1BB-based CAR targeting a membrane-distal CD22 epitope

2020 ◽  
Vol 8 (2) ◽  
pp. e000896
Author(s):  
Talia Velasco-Hernandez ◽  
Samanta Romina Zanetti ◽  
Heleia Roca-Ho ◽  
Francisco Gutierrez-Aguera ◽  
Paolo Petazzi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
High Affinity ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

BackgroundThere are few therapeutic options available for patients with B-cell acute lymphoblastic leukemia (B-ALL) relapsing as CD19– either after chemotherapy or CD19-targeted immunotherapies. CD22-chimeric antigen receptor (CAR) T cells represent an attractive addition to CD19-CAR T cell therapy because they will target both CD22+CD19– B-ALL relapses and CD19– preleukemic cells. However, the immune escape mechanisms from CD22-CAR T cells, and the potential contribution of the epitope binding of the anti-CD22 single-chain variable fragment (scFv) remain understudied.MethodsHere, we have developed and comprehensively characterized a novel CD22-CAR (clone hCD22.7) targeting a membrane-distal CD22 epitope and tested its cytotoxic effects against B-ALL cells both in in vitro and in vivo assays.ResultsConformational epitope mapping, cross-blocking, and molecular docking assays revealed that the hCD22.7 scFv is a high-affinity binding antibody which specifically binds to the ESTKDGKVP sequence, located in the Ig-like V-type domain, the most distal domain of CD22. We observed efficient killing of B-ALL cells in vitro, although the kinetics were dependent on the level of CD22 expression. Importantly, we show an efficient in vivo control of patients with B-ALL derived xenografts with diverse aggressiveness, coupled to long-term hCD22.7-CAR T cell persistence. Remaining leukemic cells at sacrifice maintained full expression of CD22, ruling out CAR pressure-mediated antigen loss. Finally, the immunogenicity capacity of this hCD22.7-scFv was very similar to that of other CD22 scFv previously used in adoptive T cell therapy.ConclusionsWe report a novel, high-affinity hCD22.7 scFv which targets a membrane-distal epitope of CD22. 4-1BB-based hCD22.7-CAR T cells efficiently eliminate clinically relevant B- CD22high and CD22low ALL primary samples in vitro and in vivo. Our study supports the clinical translation of this hCD22.7-CAR as either single or tandem CD22–CD19-CAR for both naive and anti-CD19-resistant patients with B-ALL.

scholarly journals 133 CRISPR/Cas9 gene-edited allogeneic CAR-T cells targeting CD33 show high preclinical efficacy against AML without long-term hematopoietic toxicity

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A143-A143
Author(s):  
Jonathan Terrett ◽  
Brigid Mcewan ◽  
Daniel Hostetter ◽  
Luis Gamboa ◽  
Meghna Kuppuraju ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antibody Drug Conjugate ◽  
T Cell Therapy ◽  
In Vivo Models ◽  
Car T Cells ◽  
Car T

BackgroundCD33 is the most consistently expressed antigen in AML, with high levels and homogeneous expression observed in malignant AML cells from most patients, including those with relapsed disease. Normal myelomonocytic cell lineages and a percentage of hematopoietic progenitors also express CD33, and the extreme myeloablation caused by the CD33-targeted antibody-drug conjugate (ADC) gemtuzumab ozogamicin reinforced concerns about targeting this antigen with more potent agents such as T-cell engaging bispecific antibodies and CAR-T cells. We have shown previously that allogeneic CRISPR/Cas9 gene-edited CAR-T cells targeting CD33 with TRAC disruption to reduce GvHD and B2M disruption to reduce allogeneic host rejection could eliminate tumors in xenograft models of AMLMethodsGiven that off-target activity of the toxin could contribute to the myeloablation seen with CD33-targeted ADCs, we created in vitro and in vivo models to examine reconstitution of the myeloid compartment following treatment of CD33-targeted allogeneic CAR-T cells.ResultsAlthough co-culture of CD34+ stem cells in vitro with our CD33-targeted allogeneic CAR-T cells did significantly deplete the cell population, colonies still formed after removal of the CAR-T cells as the presumably CD33-negative stem/progenitor cells expanded and differentiated. A similar phenomenon was observed in vivo with CD34 humanized mice bearing an AML tumor (THP-1 cells) and treated with the CD33-targeted allogeneic CAR-T cells. The CAR-T cells completely eradicated the THP-1 tumor but did not lead to long-term myelosuppression or B cell aplasia.ConclusionsThus, allogeneic CRISPR/Cas9 multiplex gene-edited CD33-targeted CAR-T cell therapy may be both efficacious and tolerable in AML.

scholarly journals 126 Regional administration of IL-12 endowed CAR T cells effectively targets systemic disease

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A135-A135
Author(s):  
Hee Jun Lee ◽  
Cody Cullen ◽  
John Murad ◽  
Jason Yang ◽  
Wen-Chung Chang ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
T Cells ◽  
T Cell ◽  
Tumor Models ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

BackgroundWhile chimeric antigen receptor (CAR) T cell therapy has shown impressive clinical efficacy for hematological malignancies,1 efficacy remains limited for solid tumors due in large part to the immunosuppressive tumor microenvironment.2 Tumor-associated glycoprotein 72 (TAG72) is an aberrantly glycosylated protein overexpressed on ovarian cancer3 and is an exciting target for CAR T cell immunotherapy. Our lab previously developed a second-generation TAG72 CAR T cell product and showed its potency against TAG72-expressing ovarian tumor cells both in vitro and in preclinical mouse models.4 We report here further modification of our TAG72 CAR T cells, with incorporation of interleukin-12 (IL-12) and interleukin-15 (IL-15), and evaluate the therapeutic benefits in peritoneal ovarian tumor models.MethodsIn this preclinical study, we build upon our earlier work with in vitro and in vivo evaluation of 9 different second-generation TAG72 CAR constructs varying in single-chain variable fragment, extracellular spacer, transmembrane, and intracellular co-stimulatory domains. We then engineer CAR T cells with two types of cytokines – IL-12 and IL-15 – and put these engineered cells against challenging in vivo tumor models.ResultsThrough in vitro and in vivo studies, we identify the most optimal construct with which we aim to evaluate in a phase 1 clinical trial targeting TAG72-positive ovarian cancer in 2021. Despite thorough optimizations to the CAR backbone, CAR T cells can be additionally engineered for improved anti-tumor response. Therefore, we further engineered CAR T cells with IL-12 or IL-15 production that greatly improves the effectiveness of TAG72-CAR T cells in difficult-to-treat in vivo tumor models. We observed that modification of CAR T cells with IL-15 displayed toxicity when regionally delivered in vivo, yet introduction of IL-12 not only demonstrated safe and superior therapeutic responses, but also allowed the regional administration of CAR T cells to address systemic disease. We are now expanding these findings by evaluating these therapies using syngeneic immunocompetent mouse tumor models.ConclusionsThe tumor microenvironment (TME) harbors various factors that thwart the killing of tumor cells by CAR T cells. Thus, CAR T cells will likely require further engineering to overcome this barrier. We show that amplifying cytokine pathways is one way to overcome the TME and improve the efficacy of CAR T cell therapy for solid tumors.ReferencesMaude SL, Teachey DT, Porter DL, Grupp SA. CD19-targeted chimeric antigen receptor T-cell therapy for acute lymphoblastic leukemia. Blood 2015 Jun 25;125(26):4017–23.Priceman SJ, Forman SJ, Brown CE. Smart CARs engineered for cancer immunotherapy. Curr Opin Oncol 2015 Nov;27(6):466–74.Chauhan SC, Vinayek N, Maher DM, Bell MC, Dunham KA, Koch MD, Lio Y, Jaggi M. Combined Staining of TAG-72, MUC1, and CA125 Improves Labeling Sensitivity in Ovarian Cancer: Antigens for Multi-targeted Antibody-guided Therapy. J Histochem Cytochem 2007 Aug;55(8):867–75.Murad JP, Kozlowska AK, Lee HJ, Ramamurthy M, Chang WC, Yazaki P, Colcher D, Shively J, Cristea M, Forman SJ, Priceman SJ. Effective Targeting of TAG72+ Peritoneal Ovarian Tumors via Regional Delivery of CAR-Engineered T Cells. Front Immunol 2018 Nov 19;9:2268.

scholarly journals Sulforaphane enhances the antitumor response of chimeric antigen receptor T cells by regulating PD-1/PD-L1 pathway

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Chunyi Shen ◽  
Zhen Zhang ◽  
Yonggui Tian ◽  
Feng Li ◽  
Lingxiao Zhou ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell Therapy ◽  
Car T

Abstract Background Chimeric antigen receptor T (CAR-T) cell therapy has limited effects in the treatment of solid tumors. Sulforaphane (SFN) is known to play an important role in inhibiting tumor growth, but its effect on CAR-T cells remains unclear. The goal of the current study was to determine whether combined CAR-T cells and SFN could provide antitumor efficacy against solid tumors. Methods The effect of combined SFN and CAR-T cells was determined in vitro using a co-culture system and in vivo using a xenograft mouse model. We further validated the effects of combination therapy in patients with cancer. Results In vitro, the combination of SFN and CAR-T cells resulted in enhanced cytotoxicity and increased lysis of tumor cells. We found that SFN suppressed programmed cell death 1 (PD-1) expression in CAR-T cells and potentiated antitumor functions in vitro and in vivo. As a ligand of PD-1, programmed cell death ligand 1 (PD-L1) expression was also decreased in tumor cells after SFN treatment. In addition, β-TrCP was increased by SFN, resulting in higher activation of ubiquitination-mediated proteolysis of PD-L1, which induced PD-L1 degradation. The combination of SFN and CAR-T cell therapy acted synergistically to promote better immune responses in vivo compared with monotherapy. In clinical treatments, PD-1 expression was lower, and proinflammatory cytokine levels were higher in patients with various cancers who received CAR-T cells and took SFN orally than that in the control group. Conclusion SFN improves the cytotoxicity of CAR-T cells by modulating the PD-1/PD-L1 pathway, which may provide a promising strategy for the combination of SFN with CAR-T cells for cancer immunotherapy.

scholarly journals Novel full-human CD22-CAR therapy overcomes resistance to previous CD19/22-CAR regimens in ALL

2021 ◽  
Author(s):  
Yue Tan ◽  
Haodong Cai ◽  
Chuo Li ◽  
Biping Deng ◽  
Weiliang Song ◽  
...  
Keyword(s):  
T Cells ◽  
Lymphoblastic Leukemia ◽  
Considerable Proportion ◽  
Target Antigen ◽  
Single Chain ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

Abstract BackgroundCD19- and/or CD22-targeted chimeric antigen receptor (CAR) T cells efficiently induced remission in patients with B acute lymphoblastic leukemia (B-ALL), but a considerable proportion of patients relapsed after both CD19- and CD22-CAR therapies associated with the loss or downregulation of target antigen. Re-infusions of the prior used CAR T cells were usually ineffective. In contrast to the frequent loss of CD19, low level of CD22 is usually present on leukemia cells post CAR therapy, suggesting that newly designed CD22-CAR therapies may be effective in these patients.MethodsA yeast full-human single-chain variable fragment (scFv) library and a high-throughput NFAT reporter assay were utilized to screen several full-human CD22-CAR candidates; CD107 assay and in vitro cytotoxicity assay was used to evaluate the effector function of CAR T cells; membrane proteome assay was conducted to determine the specificity of the CAR toward the target antigen; a leukemia animal models was used to test the in vivo efficacy of CAR T cells. A phase I trial (ChiCTR2000028793) was conducted to assess the safety and effectiveness of CD22-CARFH80 therapy in 8 children with B-ALL resistant to or relapsed after prior CD19- and CD22-CAR treatment.ResultsWe identified a full-human CD22-CAR construct termed CD22CARFH80 which could mediate superior anti-leukemia activity in vitro and in a leukemia animal model and had good specificity to the target antigen. Data from the trial showed that with CD22-CARFH80 T-cell therapy, 6/8 (75%) patients including 2 who had CD22low blasts achieved complete remission; 1 patient had a partial response. CAR T cells efficiently expanded in vivo, while the toxic effect is low in most patients. At a median follow-up of 5 months, 4/6 (57%) patients remained in remission.ConclusionsTherapy with a newly invented CD22-CARFH80 overcomes the resistance to prior versions of CD19- and CD22-CAR formats and elicits potent anti-leukemia responses with an acceptable safety profile, representing a promising salvage regimen for B-ALL that fails in prior CD19- and CD22-CAR treatments.Trial registrationClinicalTrials.gov: ChiCTR2000028793; registered 4 January, 2020. http://www.chictr.org.cn/showproj.aspx?proj=47857

scholarly journals IMMU-20. EVALUATION OF CAR T CELLS IN EPENDYMOMA

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii364-iii364
Author(s):  
Anandani Nellan ◽  
Andrew Donson ◽  
Jacob Calhoun ◽  
Andrea Griesinger ◽  
Terry Fry ◽  
...  
Keyword(s):  
T Cells ◽  
Brain Tumors ◽  
Tumor Cells ◽  
Second Generation ◽  
High Risk Patient ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

Abstract BACKGROUND Ependymoma is the third most common pediatric brain tumor and current treatment still results in a 10-year relapse rate of over 70% in the highest risk groups. The treatment refractory nature of ependymoma to standard therapies strongly supports the development of novel interventions. Ependymoma tumor cells express HER2 and there are active clinical trials treating children with ependymoma using local delivery of second-generation HER2 CAR T cells. METHODS Two high-risk patient-derived ependymoma cell lines, MAF811 and MAF928, that display HER2 surface expression are used for testing. We tested second-generation HER2-BBz CAR T cells in vitro and in vivo. RESULTS HER2 CAR T cells effectively kill ependymoma tumor cells in culture, but this strategy cannot eradicate the same tumor cells in mice when implanted in the fourth ventricle of the brain. HER2 CAR T cells proliferate and traffic into the tumor, but this causes a dramatic influx of immune cells, tumor swelling and lethal toxicity in a subset of mice. Mice that survive this initial tumor swelling, display significant tumor shrinkage but all tumors eventually start growing again. Ependymoma tumor cells release high amounts of inflammatory chemokines that strongly attract neutrophils and monocytes to the tumor, compared to other brain tumors, and can downregulate HER2 expression to escape recognition by CAR T cells. CONCLUSION The immunosuppressive microenvironment as well as tumor heterogeneity make HER2 CAR T cells ineffective in ependymoma. Studying these two hurdles in CAR T cell therapy is critical to effectively treat brain tumors with CAR T cells.

scholarly journals Switch receptor T3/28 improves long-term persistence and antitumor efficacy of CAR-T cells

2021 ◽  
Vol 9 (12) ◽  
pp. e003176
Author(s):  
Songbo Zhao ◽  
Chunhua Wang ◽  
Ping Lu ◽  
Yalin Lou ◽  
Huimin Liu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antitumor Activity ◽  
Lymphoid Leukemia ◽  
T Cell Therapy ◽  
Cell Therapies ◽  
Car T Cells ◽  
Car T

BackgroundChimeric antigen receptor (CAR) T cells have been successfully used in tumor immunotherapy due to their strong antitumor responses, especially in hematological malignancies such as B cell acute lymphoid leukemia. However, on-target off-tumor toxicity and poor persistence severely limit the clinical application of CAR-T cell therapy.MethodsT-cell immunoglobulin mucin domain molecule 3 (TIM-3) was used to develop a second-generation 41BB CD19 CAR linked with a T3/28 chimera, in which truncated extracellular TIM-3 was fused with the CD28 transmembrane and cytoplasmic domains. The efficacy of T3/28 CAR-T cells was evaluated in vitro and in vivo.ResultsWe demonstrated that the switch receptor T3/28 preserved the TCM phenotype, improved proliferative capacity, and reduced exhaustion of CAR-T cells, resulting in superior in vitro and in vivo antitumor activity in B lymphoma. Importantly, the switch receptor T3/28 substantially prolonged the persistence of CAR-T cells, and the interleukin-21/Stat3 axis probably contributed to the enhanced cytotoxicity of T3/28 CAR-T cells.ConclusionOverall, the T3/28 chimera significantly prolonged the persistence of CAR-T cells, and T3/28 CAR-T cells possessed potent antitumor activity in mice, shedding new light on potential improvements in adoptive T cell therapies.

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