scholarly journals Live attenuated bacterium limits cancer resistance to CAR-T therapy by remodeling the tumor microenvironment

2022 ◽  
Vol 10 (1) ◽  
pp. e003760
Author(s):  
Fengguang Guo ◽  
Jugal K Das ◽  
Koichi S Kobayashi ◽  
Qing-Ming Qin ◽  
Thomas A Ficht ◽  
...  

The tumor microenvironment (TME) is characterized by the activation of immune checkpoints, which limit the ability of immune cells to attack the growing cancer. To overcome immune suppression in the clinic, antigen-expressing viruses and bacteria have been developed to induce antitumor immunity. However, the safety and targeting specificity are the main concerns of using bacteria in clinical practice as antitumor agents. In our previous studies, we have developed an attenuated bacterial strain (Brucella melitensis 16M ∆vjbR, henceforth Bm∆vjbR) for clinical use, which is safe in all tested animal models and has been removed from the select agent list by the Centers for Disease Control and Prevention. In this study, we demonstrated that Bm∆vjbR homed to tumor tissue and improved the TME in a murine model of solid cancer. In addition, live Bm∆vjbR promoted proinflammatory M1 polarization of tumor macrophages and increased the number and activity of CD8+ T cells in the tumor. In a murine colon adenocarcinoma model, when combined with adoptive transfer of tumor-specific carcinoembryonic antigen chimeric antigen receptor CD8+ T cells, tumor cell growth and proliferation was almost completely abrogated, and host survival was 100%. Taken together, these findings demonstrate that the live attenuated bacterial treatment can defeat cancer resistance to chimeric antigen receptor T-cell therapy by remodeling the TME to promote macrophage and T cell-mediated antitumor immunity.

2021 ◽  
Vol 12 ◽  
Author(s):  
Javad Khanali ◽  
Mohammadreza Azangou-Khyavy ◽  
Melika Boroomand-Saboor ◽  
Mobina Ghasemi ◽  
Hassan Niknejad

Recent advances in cancer immunotherapy have attracted great interest due to the natural capacity of the immune system to fight cancer. This field has been revolutionized by the advent of chimeric antigen receptor (CAR) T cell therapy that is utilizing an antigen recognition domain to redirect patients’ T cells to selectively attack cancer cells. CAR T cells are designed with antigen-binding moieties fused to signaling and co-stimulatory intracellular domains. Despite significant success in hematologic malignancies, CAR T cells encounter many obstacles for treating solid tumors due to tumor heterogeneity, treatment-associated toxicities, and immunosuppressive tumor microenvironment. Although the current strategies for enhancing CAR T cell efficacy and specificity are promising, they have their own limitations, making it necessary to develop new genetic engineering strategies. In this article, we have proposed a novel logic gate for recognizing tumor-associated antigens by employing intracellular JAK/STAT signaling pathway to enhance CAR T Cells potency and specificity. Moreover, this new-generation CAR T cell is empowered to secrete bispecific T cell engagers (BiTEs) against cancer-associated fibroblasts (CAFs) to diminish tumor metastasis and angiogenesis and increase T cell infiltration.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xin Jin ◽  
Wenyi Lu ◽  
Meng Zhang ◽  
Xia Xiong ◽  
Rui Sun ◽  
...  

Chimeric antigen receptor (CAR)-T cell therapy has become an important method for the treatment of hematological tumors. Lentiviruses are commonly used gene transfer vectors for preparing CAR-T cells, and the conditions for preparing CAR-T cells vary greatly. This study reported for the first time the influence of differences in infection temperature on the phenotype and function of produced CAR-T cells. Our results show that infection at 4 degrees produces the highest CAR-positive rate of T cells, infection at 37 degrees produces the fastest proliferation in CAR-T cells, and infection at 32 degrees produces CAR-T cells with the greatest proportion of naive cells and the lowest expression of immune checkpoints. Therefore, infection at 32 degrees is recommended to prepare CAR-T cells. CAR-T cells derived from infection at 32 degrees seem to have a balance between function and phenotype. Importantly, they have increased oncolytic ability. This research will help optimize the generation of CAR-T cells and improve the quality of CAR-T cell products.


2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii345-iii345
Author(s):  
Hsin-Hung Chen ◽  
Yi-Wei Chen

Abstract A 6 y/o girl with recurrent multifocal glioblastoma received 3 times of boron neutron capture therapy (BNCT) and chimeric antigen receptor (CAR)–engineered T cells targeting the tumor-associated antigen HER2. Multiple infusions of CAR T cells were administered over 30 days through intraventricular delivery routes. It was not associated with any toxic effects of grade 3 or higher. After BNCT and CAR T-cell treatment, regression of all existing intracranial lesions were observed, along with corresponding increases in levels of cytokines and immune cells in the cerebrospinal fluid, but new lesions recurred soon after the treatment. This clinical response continued for 14 months after the initiation of first recurrence.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248973
Author(s):  
Nami Iwamoto ◽  
Bhavik Patel ◽  
Kaimei Song ◽  
Rosemarie Mason ◽  
Sara Bolivar-Wagers ◽  
...  

Achieving a functional cure is an important goal in the development of HIV therapy. Eliciting HIV-specific cellular immune responses has not been sufficient to achieve durable removal of HIV-infected cells due to the restriction on effective immune responses by mutation and establishment of latent reservoirs. Chimeric antigen receptor (CAR) T cells are an avenue to potentially develop more potent redirected cellular responses against infected T cells. We developed and tested a range of HIV- and SIV-specific chimeric antigen receptor (CAR) T cell reagents based on Env-binding proteins. In general, SHIV/SIV CAR T cells showed potent viral suppression in vitro, and adding additional CAR molecules in the same transduction resulted in more potent viral suppression than single CAR transduction. Importantly, the primary determinant of virus suppression potency by CAR was the accessibility to the Env epitope, and not the neutralization potency of the binding moiety. However, upon transduction of autologous T cells followed by infusion in vivo, none of these CAR T cells impacted either acquisition as a test of prevention, or viremia as a test of treatment. Our study illustrates limitations of the CAR T cells as possible antiviral therapeutics.


Surgery ◽  
2018 ◽  
Vol 163 (3) ◽  
pp. 627-632 ◽  
Author(s):  
Ramesh B. Batchu ◽  
Oksana V. Gruzdyn ◽  
Ebrahem M. Mahmud ◽  
Fatme Chukr ◽  
Rajesh Dachepalli ◽  
...  

2019 ◽  
Vol 20 (10) ◽  
pp. 2469 ◽  
Author(s):  
Hyeon Joo Yoo ◽  
Yibin Liu ◽  
Lei Wang ◽  
Maria-Luisa Schubert ◽  
Jean-Marc Hoffmann ◽  
...  

Chimeric antigen receptor T cell (CART) therapy is currently one of the most promising treatment approaches in cancer immunotherapy. However, the immunosuppressive nature of the tumor microenvironment, in particular increased reactive oxygen species (ROS) levels, provides considerable limitations. In this study, we aimed to exploit increased ROS levels in the tumor microenvironment with prodrugs of ROS accelerators, which are specifically activated in cancer cells. Upon activation, ROS accelerators induce further generation of ROS. This leads to an accumulation of ROS in tumor cells. We hypothesized that the latter cells will be more susceptible to CARTs. CD19-specific CARTs were generated with a CD19.CAR.CD28.CD137zeta third-generation retroviral vector. Cytotoxicity was determined by chromium-51 release assay. Influence of the ROS accelerators on viability and phenotype of CARTs was determined by flow cytometry. The combination of CARTs with the ROS accelerator PipFcB significantly increased their cytotoxicity in the Burkitt lymphoma cell lines Raji and Daudi, as well as primary chronic lymphocytic leukemia cells. Exposure of CARTs to PipFcB for 48 h did not influence T cell exhaustion, viability, or T cell subpopulations. In summary, the combination of CARTs with ROS accelerators may improve adoptive immunotherapy and help to overcome tumor microenvironment-mediated treatment resistance.


2019 ◽  
Vol 14 (1) ◽  
pp. 60-69
Author(s):  
Manxue Fu ◽  
Liling Tang

Background: Chimeric Antigen Receptor (CAR) T cell immunotherapy, as an innovative method for tumor immunotherapy, acquires unprecedented clinical outcomes. Genetic modification not only provides T cells with the antigen-binding function but also endows T cells with better immunological functions both in solid and hematological cancer. However, the CAR T cell therapy is not perfect because of several reasons, such as tumor immune microenvironment, and autologous limiting factors of CAR T cells. Moreover, the safety of CAR T cells should be improved.Objective:Recently many patents and publications have reported the importance of CAR T cell immunotherapy. Based on the patents about CAR T cell immunotherapy, we conclude some methods for designing the CAR which can provide information to readers.Methods:In this review, we collect recent patents and publications, summarize some specific antigens for oncotherapy from patents and enumerate some approaches to conquering immunosuppression and reinforcing the immune response of CAR T cells. We also sum up some strategies for improving the safety of CAR T cell immunotherapy.Results:CAR T cell immunotherapy as a neotype cellular immunotherapy has been proved effective in oncotherapy and authorized by FDA. Improvements in CAR designing enhance functions of CAR T cells.Conclusion:This review, summarizing antigens and approaches to overcome defects of CAR T cell immunotherapy from patents and publications, might contribute to a broad readership.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Chunyi Shen ◽  
Zhen Zhang ◽  
Yi Zhang

Immunotherapy, especially based on chimeric antigen receptor (CAR) T cells, has achieved prominent success in the treatment of hematological malignancies. However, approximately 30-50% of patients will have disease relapse following remission after receiving CD19-targeting CAR-T cells, with failure of maintaining a long-term effect. Mechanisms underlying CAR-T therapy inefficiency consist of loss or modulation of target antigen and CAR-T cell poor persistence which mostly results from T cell exhaustion. The unique features and restoration strategies of exhausted T cells (Tex) have been well described in solid tumors. However, the overview associated with CAR-T cell exhaustion is relatively rare in hematological malignancies. In this review, we summarize the characteristics, cellular, and molecular mechanisms of Tex cells as well as approaches to reverse CAR-T cell exhaustion in hematological malignancies, providing novel strategies for immunotherapies.


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