scholarly journals Co-expression of IL-7 and PH20 Promote anti-GPC3 CAR-T Tumor Suppressor Activity in Vivo and in Vitro

2020 ◽  
Author(s):  
Qian Liu ◽  
Cixiao Wang ◽  
Zeyou Jiang ◽  
Su-yang Yue

Abstract While CAR-T therapy has successfully treated hematological malignancies, it has proved sub-optimal for solid tumors. The main limitation is the inability of CAR-T cells to infiltrate and then proliferate within tumors. In this study, we co-expressed IL-7 and PH20, a type of hyaluronidase, with CAR targeting GPC3 (G3CAR-7×20) to address these issues. We found (G3CAR-7×20) exhibited better proliferation in vivo and in vitro than G3CAR, reduced the level of apoptosis after stimulation by tumor cells, and maintained the memory phenotype of CAR-T cells. G3CAR-7×20 also increased the ability of CAR-T cells to infiltrate tumor tissue. G3CAR-7×20 may significantly enhance the efficacy of CAR-T cells in solid tumors.

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Min Meng ◽  
Yi-chen Wu

Background. Chimeric antigen receptor-modified T cell (CAR-T) therapy has great potential for treating malignant tumors, especially hematological malignancies. However, the therapeutic effect of solid tumors is limited. One of the most important factors is the homing of CAR-T cells to tumor tissues in vivo. Method. a recombinant adeno-associated virus 2 (AAV2) subtype carrying the CCL19 gene was used to pretreat the tumor before the Glypican-3 (GPC3) CAR-T treatment. The tumor tissue continuously expressed CCL19 and analyzed the tumor-suppressive effect of AAV-CCL19 on GPC3 CAR-T by in vitro and in vivo experiments. Result. Under the chemotaxis of CCL19, CAR-T cells had a significant increase in the degree of tumor tissue infiltration; also, the antitumor effect in vitro was significantly enhanced. AAV-CCL19 combined with GPC3 CAR-T significantly increased the survival time of mice. The aforementioned results showed that the combination of AAV-CCL19 and GPC3 CAR-T cells effectively increased the ability of CAR-T cells to go home into the tumor tissue, making the CAR-T cell treatment more effective. Conclusion. This study is expected to solve the dilemma in treating CAR-T cell solid tumors and achieve better clinical results.


2020 ◽  
Author(s):  
Qibin Liao ◽  
Yunyu Mao ◽  
Huan He ◽  
Xiangqing Ding ◽  
Xiaoyan Zhang ◽  
...  

Abstract Background: On-target off-tumor toxicity impedes the clinical application of chimeric antigen receptor-modified T cells (CAR-T cells) in the treatment of solid tumors. The combinatorial antigen recognition strategy can improve the therapeutic safety of CAR-T cells by targeting two different tumor-associated antigens (TAAs) using a CAR and a chimeric costimulatory receptor (CCR). Although programmed death-ligand 1 (PD-L1, also known as B7-H1) is expressed on multiple tumors, the potential of PD-L1 as a universal target for designing CCR remains unknown.Methods: A first-generation CD19 or HER2 CAR and a PD-L1 CCR containing the CD28 signaling domain were constructed and delivered into Jurkat T cells or primary T cells by a pseudotyped lentivirus. The release of cytokines, including IL-2, IFN-γ and TNF-α, was quantified using enzyme-linked immunosorbent assay (ELISA) kits or a cytometric bead array (CBA). The in vitro cytotoxicity of CAR-T cells was detected with a luciferase-based killing assay. The in vitro proliferation of CAR-T cells was assessed by flow cytometry. The therapeutic safety and efficacy of CAR-T cells was evaluated using a subcutaneous dual-tumor model in vivo.Results: Jurkat T cells or primary T cells expressing both the CD19/HER2 CAR and PD-L1 CCR produced higher levels of cytokines in the presence of CD19/HER2 and PD-L1 than in the presence of HER2/CD19. Compared to HER2-z-engineered T cells, HER2-z-PD-L1-28-engineered T cells had higher in vitro cytotoxicity potential against PD-L1-positive tumor cells. CD19/HER2-z-PD-L1-28-engineered T cells showed higher proliferation potential in the presence of CD19/HER2 and PD-L1 than in the absence of PD-L1. CD19/HER2-z-PD-L1-28-engineered T cells preferably destroyed xenograft tumors expressing CD19/HER2 and PD-L1 in vivo and did not significantly affect CD19/HER2-expressing tumors. The PD-L1 CCR improved the antitumor efficacy of low-affinity HER2 CAR-T cells against PD-L1-positive tumors expressing high levels of HER2.Conclusion: Our findings confirmed that PD-L1 can be used as a universal target antigen for designing CCR, improving the efficacy of CAR-T cells in the treatment of PD-L1-positive solid tumors but reducing toxicity within PD-L1-negative normal tissues expressing low levels of TAA in vivo.


2021 ◽  
Vol 9 (4) ◽  
pp. e002173
Author(s):  
Guanmeng Wang ◽  
Xin Zhou ◽  
Giovanni Fucà ◽  
Elena Dukhovlinova ◽  
Peishun Shou ◽  
...  

BackgroundChimeric antigen receptor (CAR) T cells are effective in B-cell malignancies. However, heterogeneous antigen expression and antigen loss remain important limitations of targeted immunotherapy in solid tumors. Therefore, targeting multiple tumor-associated antigens simultaneously is expected to improve the outcome of CAR-T cell therapies. Due to the instability of single-chain variable fragments, it remains challenging to develop the simultaneous targeting of multiple antigens using traditional single-chain fragment variable (scFv)-based CARs.MethodsWe used Humabody VH domains derived from a transgenic mouse to obtain fully human prostate-specific membrane antigen (PSMA) VH and mesothelin (MSLN) VH sequences and redirect T cell with VH based-CAR. The antitumor activity and mode of action of PSMA VH and MSLN VH were evaluated in vitro and in vivo compared with the traditional scFv-based CARs.ResultsHuman VH domain-based CAR targeting PSMA and MSLN are stable and functional both in vitro and in vivo. VH modules in the bispecific format are capable of binding their specific target with similar affinity as their monovalent counterparts. Bispecific CARs generated by joining two human antibody VH domains can prevent tumor escape in tumor with heterogeneous antigen expression.ConclusionsFully human antibody VH domains can be used to generate functional CAR molecules, and redirected T cells elicit antitumoral responses in solid tumors at least as well as conventional scFv-based CARs. In addition, VH domains can be used to generate bispecific CAR-T cells to simultaneously target two different antigens expressed by tumor cells, and therefore, achieve better tumor control in solid tumors.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A146-A146
Author(s):  
Jihyun Lee ◽  
Areum Park ◽  
Jungwon Choi ◽  
Dae Gwan Yi ◽  
Hee Jung Yang ◽  
...  

BackgroundChimeric antigen receptor (CAR) -T cell therapies have proven to be effective against various liquid tumors. However, the development of CAR-T against solid tumors has been challenging due to insufficient efficacy and potential on-target off-tumor toxicities caused by low expression of tumor antigens on normal tissues. Testing various affinities of CARs has demonstrated that lower affinity CARs maintain its anti-tumor effect while minimizing safety concerns (1). In order to develop a CAR-T against solid tumors expressing Mucin1, we have screened for Mucin1 binding antibodies and tested their anti-tumor effect in vitro and in vivo. The potential of on-target off-tumor toxicity was also measured in vitro.MethodsAnti-Mucin1 human single chain variable fragments (scFv) were obtained via screening against a scFv display library. Anti-Mucin1 scFvs were incorporated into CARs and in vitro, in vivo functions against various tumor cells expressing Mucin1 were tested. For in vivo studies, tumor bearing NOG mice (HCC1954 cells) received anti-Mucin1 CAR-T cells. Therapeutic efficacy was evaluated by measuring tumor volumes. Potential on-target off-tumor toxicity against Mucin1 on normal cells was tested by investigating the killing effect of anti-Mucin1 CAR-T against cancer cell line (HCC70) and non-tumorigenic breast epithelial cell line (MCF-10A) in co-culture systemsResultsIn vitro activity of anti-Mucin1 CAR-T cells that displayed a range of affinities for Mucin1 (27nM to 320nM) showed similar cytokine secretion levels and cytotoxicity against Mucin-1 expressing tumor cell lines (HCC70 and T47D). Robust anti-tumor activity was also demonstrated in vivo against large tumors (400~500 mm3) with relatively small numbers of CAR-T cells (0.5 x 106 CAR-T cells per mouse). In vivo expansion of CAR-T cells were observed in all scFv-CAR-T cases and accompanied by close to complete regression of tumors within 25 days post CAR-T cell injection. Of the 4 scFv CAR-Ts, 2H08 (with a Kd of 94nM) was tested for activity against normal breast epithelial cells. When 2H08-CAR-T was cocultured with a mixture of HCC70 and MCF-10A cells, they preferentially killed only the Mucin1 overexpressing HCC70 cells leaving MCF-10 cells intact.ConclusionsOur study demonstrates anti-tumor activity of a novel scFv-derived CAR-T recognizing Mucin1 and its effectiveness in large pre-established tumors in vivo. We also demonstrate that 2H08-CAR-T can distinguish between target overexpressing cancer cells and normal epithelial cells, which suggests that by toning down the affinity of CAR against antigen one can improve the safety profile of solid tumor antigen targeting CAR-T cell therapies.ReferenceCastellarin M, Sands C, Da T, Scholler J, Graham K, Buza E, Fraietta J, Zhao Y, June C. A rational mouse model to detect on-target, off-tumor CAR T cell toxicity. JCI Insight 2020; 5:e136012Ethics ApprovalAll experiments were done under protocols approved by the Institutional Animal Care and Use Committee (IACUC) (Study#LGME21-011).ConsentWritten informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2530-2530
Author(s):  
Daniel Lee ◽  
Andy J Minn ◽  
Lexus R Johnson

2530 Background: Neoantigen depleted malignancies such as colorectal cancer demonstrate primary resistance to immune checkpoint blockade, and solid tumors in general have shown resistance to chimeric antigen receptor (CAR) T cell therapy. However, CAR-T cells have been shown to be capable of delivering various therapeutic molecules in a targeted fashion to the tumor microenvironment, in some cases through extracellular vesicles (EVs). In vivo studies have shown that the presentation of foreign viral peptides by solid tumors can reprogram bystander virus-specific cytotoxic T cells (CTLs) against tumor cells. In this study, we demonstrate that CAR-T cells can deliver engineered peptide antigens to solid tumors, leading to presentation on tumor cells and anti-tumor response. Methods: Second generation CAR-T cells (41BB endodomain) targeting human CD19 (19BBz) or human mesothelin (M5BBz) were generated via retroviral and lentiviral transduction respectively. CAR-T cells were engineered to co-express peptides such as SIINFEKL of ovalbumin and NLVPMVATV of CMV pp65 among others. Peptides were isolated from EVs via ultracentrifugation. For in vivo studies, C57BL/6 or NSG mice were injected on the flank with relevant tumors and treated with peptide-CAR-T cells. In vitro studies utilized flow cytometry and xCELLigence killing assays. Results: Murine 19BBz CAR-T cells expressing the SIINFEKL peptide of ovalbumin (ova-19BBz) were found to transfer SIINFEKL peptide to tumor cells via EVs in vitro and in vivo, leading to peptide presentation on MHC-I of tumor cells. This resulted in significantly delayed tumor growth in tumor bearing mice transfused with OT-I T cells to mimic an existing antigen specific T cell pool. We expanded on these findings by isolating EVs from human M5BBz CAR-T cells expressing CMV viral peptides. Peptide-CAR-T EVs were co-cultured with human ovarian cancer cells to assess presentation to Jurkat T cells. Finally, we utilized primary human T cells from CMV+ healthy donors to assess the clinical feasibility of our peptide delivery approach. Conclusions: CAR-T cells can be engineered to deliver peptides to tumor cells for presentation and subsequent targeting by antigen specific CTLs. This represents a novel strategy for the treatment of non-immunogenic tumors.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A140-A141
Author(s):  
David Mai ◽  
Omar Johnson ◽  
Carl June

BackgroundCAR-T cell therapy has demonstrated remarkable success in hematological malignancies but displays limited efficacy in solid tumors, which comprise most cancer cases. Recent studies suggest that CAR-T cell failure via T cell exhaustion is characterized by decreased surface CAR expression, cytotoxicity, and Th1 cytokine production, leading to reduced antitumor functionality.1 2 3 To address these issues, studies have turned to genetically knocking out or overexpressing targets associated with an exhaustion or effector phenotype, such as PD-1 knockout (KO) and c-Jun overexpression, among other candidates that are typically receptors or transcription factors.4 5 6 However, there are other underexplored factors that mediate various aspects of immune regulation. While genome-wide CRISPR screens may discover such factors, they are unlikely to reveal phenotypes for genes whose function is partially redundant, therefore promising candidates may be missed. Such candidates include post-transcriptional regulators (PTRs) that coordinate immune responses, which are less well-studied in the context of CAR-T cell function. We hypothesized that KO of these PTRs may increase CAR-T cell cytokine activity, phenotype, and persistence, potentially under long-term or exhaustion-inducing conditions, leading to increased tumor control. Ultimately, disruption of negative immune regulators could produce CAR-T cells with enhanced activity and persistence, narrowing the gap between efficacy in hematological and solid tumors.MethodsTo explore whether the disruption of two target PTRs improves solid tumor efficacy, we used CRISPR-Cas9 to genetically delete one or both PTRs in mesothelin-targeting human CAR-T cells and assayed their function in vitro and in vivo in NSG mice.ResultsWe show successful genetic deletion of these genes in post-thymic human T cells and that their disruption does not affect primary expansion (figure 1) or transduction efficiency (figure 2). These KO CAR-T cells display increased expression of co-stimulatory receptors and various cytokines (figure 3). While KO CAR-T cells are functionally similar to WT CAR-T cells in in vitro assays (figure 4), KO CAR-T cells demonstrate superior activity in vivo and can clear large, established tumors compared to WT CAR-T cells at low dose (figure 5).Abstract 131 Figure 1Expansion kinetics of KO CAR-T cellsAbstract 131 Figure 2Transduction efficiency and baseline phenotype of KO CAR-T cellsAbstract 131 Figure 3Costimulatory receptor and cytokine expression of KO CAR-T cellsAbstract 131 Figure 4In vitro cytotoxicity of KO CAR-T cellsAbstract 131 Figure 5In vivo activity of KO CAR-T cellsConclusionsThese results indicate that KO of our target PTRs may improve the potency of CAR-T cells in solid tumors and may have important implications on the development of effective solid-tumor cell therapies.ReferencesJE Wherry and M Kurachi, Molecular and cellular insights into T cell exhaustion, Nature Reviews Immunology 2015;15:486–499.EW Weber, et al. Transient rest restores functionality in exhausted CAR-T cells through epigenetic remodeling. Science 2021;372:6537.S Kuramitsu et al. Induction of T cell dysfunction and NK-like T cell differentiation in vitro and in patients after CAR T cell treatment. Cell, in revision.BD Choi et al, CRISPR-Cas9 disruption of PD-1 enhances activity of university EGFRvIII CAR T cells in a preclinical model of human glioblastoma. Journal for ImmunoTherapy of Cancer 2019;7:304.RC Lynn et al. c-Jun overexpression in CAR T cells induces exhaustion resistance. Nature 2019;576:293–300.LJ Rupp et al. CRISPR/Cas9-mediated PD-1 disruption enhances anti-tumor efficacy of human chimeric antigen receptor T cells. Scientific Reports 2017;7:737.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A582-A582
Author(s):  
Peter DeMuth ◽  
Amy Tavares ◽  
Ana Castano

BackgroundGenetic engineering of T cells to express anti-CD19 Chimeric Antigen Receptors (CAR-T cells) has been FDA approved for the treatment of refractory/relapsing acute lymphocytic leukemia and diffuse large B cell lymphoma. With more patients receiving treatment with CAR-T cells it has been observed that approximately 10–20% of patients fail to enter remission after therapy,1 and 30–50% of patients who achieve remission with anti-CD19 CAR T cells have disease relapse.2 In prior studies, CAR-binding amphiphile (AMP)-peptides were shown to effectively localize in lymph nodes (LN), where they decorate endogenous antigen-presenting cells (APC) and stimulate CAR signaling to promote potent CAR-T responses against solid tumors.3 In this study, we describe how CD19 mimotope peptides specific for FMC63-based CARs can be modified with AMP technology to enhance peptide accumulation in LNs, enable presentation on APCs to CAR-Ts, and promote activation and effector functionality of CAR-T cells.MethodsWe performed phage-screening and enrichment for CD19 surrogate peptides recognized by FMC-63-scFv. Surface Plasmon Resonance (SPR) was utilized to evaluate the affinity of the peptides to immobilized FMC-63. AMP versions of peptides were generated. In vitro, human dendritic cells (DCs) were preconditioned with AMP-CD19 or soluble peptides and cocultured with autologous T cells engineered to express CD19 CARs (FMC63-28z and FMC63-41BBz). Markers for activation, proliferation, cytotoxicity, and effector functions were evaluated. In vivo experiments were performed to evaluate the biodistribution of peptides. Luciferase-expressing murine CAR-T cells were engineered to evaluate the expansion and biodistribution of CAR-T cells in combination with AMP or soluble regimens.ResultsWe found surrogate CD19 peptide mimotopes that bind to FMC-63 with different affinities evaluated by ELISA and SPR. Assessment in human autologous DC/CAR-T cell cocultures demonstrated that AMP-CD19 peptides can decorate DCs effectively and promote potent activation (OX40, 41BB, CD69), proliferation, cytokine production (IFNγ, TNFα, and IL2), cytotoxicity (CD107a), and phenotypic enhancement of CD19-specific CAR-T cells. Assessment in vivo showed that AMPs are effectively delivered to LN where endogenous APCs are decorated to promote the activity of murine CAR-T cells.ConclusionsIn vitro, AMP modification of CAR-binding peptide mimotopes induces activation, cytotoxicity, and effector functions of CAR-T cells. These AMP-peptides effectively accumulate in LN and boost CAR-T activation and expansion in vivo. This platform can potentially be utilized as a mechanism to expand and functionally enhance CAR-T cells in vivo for blood and solid tumors.ReferencesMaude SL et al. Tisagenlecleucel in children and young adults with B-cell lymphoblastic leukemia. N Engl J Med 2018;378:439–448.Park JH et al. Long-term follow-up of CD19 CAR therapy in acute lymphoblastic leukemia. N Engl J Med 2018;378:449–459.Ma L et al. Enhanced CAR–T cell activity against solid tumors by vaccine boosting through the chimeric receptor. Science 2019;365(6449):162–168.Ethics ApprovalAll animal experiments in this study were performed in accordance with the approval of IACUC Protocol CR-0039.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4806-4806
Author(s):  
Yuxiang Tang ◽  
Heng Mei ◽  
ZhaoZhao Chen ◽  
Weiqi Yao ◽  
Chenggong Li ◽  
...  

Abstract Background : The presence of tumor immunosuppressive microenvironment, abnormal vascular microenvironment, and the presence of a cross-linked matrix barrier may hinder the recruitment, proliferation, and activation of CAR-T to lymphoma tissue infiltration, which limit the efficacy of CAR-T in the treatment of lymphoma. The enhanced infiltration effect of ICG photothermal effect on CAR-T and the effect of LY on improving tumor immunosuppressive microenvironment have been confirmed. In this work, we have constructed LY/ICG@HES-PCL nanomedicine to improve the accumulation, proliferation and activation of CAR-T in lymphoma tissue, further improving the therapy efficacy of CAR-T in lymphoma. Methods: The effect of LY/ICG@HES-PCL on the proliferation and activation of CAR-T was studied by Transwell experiment. LY/ICG@HES-PCL was studied in vivo to investigate its improving the efficacy of CAR-T therapy in lymphoma. Biefly, 1×10 7 Raji human lymphoma cells were subcutaneously injected into both sides of each mouse. After ≈20 days, when the tumor volume reached ≈100 mm 3, mice were randomly assigned to 5 groups (n=6) and were treated by PBS, ICG@HES-PCL, ICG@HES-PCL+NIR, LY/ICG@HES-PCL, LY/ICG@HES-PCL+NIR, respectively. (4.0 mg/kg as ICG, 4.0 mg/kg as ICG). NIR groups were irradiated with an 808 nm laser at the power density of 0.3 W cm −2 for 10 mins. Two hours later, 1 × 10 7 CAR-T cells were intravenously injected into the mice. The tumor sizes were recorded by a digital caliper every 3 days. LY/ICG@HES-PCL in vivo was monitored using an in vivo bioluminescence imaging system. Lymphoma microenvironment was analyzed by immunofluorescence and FCM. Results: LY/ICG@HES-PCL increased CAR-T quantity by 3.7 times, IL-2 and IFN-λ release by 2.5 and 2.1 times in vitro, increased CAR-T accumulation in tumor tissue by 4.45 times within 3 days in vivo, achieving CAR-T activation, proliferation, and tumor accumulation enhancement. LY/ICG@HES-PCL improved CAR T efficacy in lymphoma by 3.4 times and CAR T longevity within 15 days by 1.6 times. Discussion: LY/ICG@HES-PCL co-delivered the photosensitifier ICG and TGF-β inhibitor LY to the lymphoma tissue. The photothermal effect of ICG decreased the density of lymphoma matrix and activated CD4+ T cells, CD8+ T cells and NK cells in tumor tissue. LY was used to inhibit PD-1 and CLTA-4 of CAR-T, so as to promotes CAR-T proliferation, improve CAR-T activity and longevity in vivo, and ultimately improve the anti-lymphoma efficacy of CAR-T cells. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A128-A128
Author(s):  
Martin Hosking ◽  
Bishwas Shrestha ◽  
Megan Boyett ◽  
Soheila Shirinbak ◽  
Angela Gentile ◽  
...  

BackgroundAlthough CAR T cells have been shown to be effective and potent in treating several hematologic malignancies, engineered T-cell therapies have had limited success in addressing solid tumors. Unlike liquid tumors where uniformly expressed antigens are accessible and can be effectively targeted, tumor access and antigen heterogeneity are a significant barrier to the successful development of CAR-T cells in solid tumors.MethodsHere we demonstrate that the combination of a bi-specific T-cell engager (BiTE) targeting EpCAM with a CAR T cell targeting HER2 enhances the in vitro and in vivo anti-tumor activity against heterogenous solid tumors.ResultsWe observed a dose-dependent enhancement of cytolytic activity when EpCAM-specific BiTEs were titrated alongside 4D5-based HER2-specific CAR T cells against HER2low tumors, enhancing maximal cytolysis by two-fold compared to CAR T cells alone (figure 1). Moreover, the escape of HER2low tumor cells in mixed heterogenous culture systems was circumvented by the combination of HER2-specific CAR T cells and EpCAM-specific BiTEs. The enhancement of efficacy was further demonstrated in an established HER2low MDA-MB-231 xenografts. HER2-specific CAR T cells were unable to contain Her2low tumors, whereas tumor growth was effectively controlled in mice receiving both EpCAM-specific BiTEs and HER2-specific CAR T cells.Abstract 116 Figure 1EpCAM specific BiTEs supplement CAR-T efficacy in vitro (A) HER2 and EpCAM expression of SKOV3, MDA-MB-231, and K562 tumor cells was assessed by flow cytometry. (B) HER2 specific CAR-T rapidly targeted and lysed HER2High SKOV3 tumor cells as measured via xCelligence RTCA assay. (C) SKOV3 were co-cultured with untransduced CD8+ T cells and the indicated concentrations of EpCAM BiTE and specific cytolysis was assessed. (D) MDA-MB-231 (HER2low) tumor cells were co-cultured with HER2 CAR-T ± EpCAM BiTE and specific cytolysis was determinedConclusionsCollectively, these data demonstrate that multi-antigen targeting mediated by BiTEs and CARs extends overall anti-tumor efficacy in preclinical models of heterogenous solid tumors. Fate Therapeutics is currently using its proprietary induced pluripotent stem cell (iPSC) product platform to generate iPSC-derived CAR T cells and iPSC-derived CAR NK cells that secrete BiTEs for the treatment of solid tumors.Ethics ApprovalThese studies were approved by Fate Therapeutics Institutional Animal Care and Use Committee and were carried out in accordance with the National Institutes of Health’s Guide for the Care and Use of Laboratory Animals.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Qibin Liao ◽  
Huan He ◽  
Yunyu Mao ◽  
Xiangqing Ding ◽  
Xiaoyan Zhang ◽  
...  

Abstract Chimeric antigen receptor-modified T cells (CAR-T cells) have shown good effects in the treatment of hematologic cancers; however, they may cause on-target off-tumor toxicity because of minimal expression of tumor-associated antigens (TAAs) on normal tissues, particularly in the context of treating solid tumors. Hypoxia is a common hallmark of solid tumors because of the Warburg effect. To minimize side effects, we designed a hypoxia-inducible CAR (HiCAR), which is driven by a hypoxia response element (HRE), and consists of a conventional CAR and an oxygen-dependent degradation domain (ODD) that is actively degraded under normoxia but stabilized under hypoxia. HiCAR-T cells showed enhanced cytotoxicity against tumor cells under hypoxia compared to normoxia in vitro and antitumor efficacy comparable to that of conventional CAR-T cells in vivo. Overall, our study demonstrates the potential of the HiCAR for improving the safety of CAR-T cells to promote the clinical application of CAR-T immunotherapy.


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