The adoptive transfer of T cells that are engineered to express chimeric antigen receptors (CARs) has shown remarkable success in treating B cell malignancies but only limited efficacy against other cancer types, especially solid tumours. Compared with haematological diseases, solid tumours present a unique set of challenges, including a lack of robustly expressed, tumour-exclusive antigen targets as well as highly immunosuppressive and metabolically challenging tumour microenvironments that limit treatment safety and efficacy. Here, we review protein- and cell-engineering strategies that seek to overcome these obstacles and produce next-generation T cells with enhanced tumour specificity and sustained effector function for the treatment of solid malignancies.
Your institute does not have access to this article
Open Access articles citing this article.
Experimental Hematology & Oncology Open Access 23 April 2022
Molecular Cancer Open Access 11 April 2022
Journal of Experimental & Clinical Cancer Research Open Access 31 March 2022
Subscribe to Nature+
Get immediate online access to the entire Nature family of 50+ journals
Subscribe to Journal
Get full journal access for 1 year
only $4.92 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
Sadelain, M., Brentjens, R. & Rivière, I. The basic principles of chimeric antigen receptor design. Cancer Discov. 3, 388–398 (2013).
Finney, H. M., Lawson, A. D. G., Bebbington, C. R. & Weir, A. N. C. Chimeric receptors providing both primary and costimulatory signaling in T cells from a single gene product. J. Immunol. 161, 2791–2797 (1998).
Finney, H. M., Akbar, A. N. & Lawson, A. D. G. Activation of resting human primary T cells with chimeric receptors: costimulation from CD28, inducible costimulator, CD134, and CD137 in series with signals from the TCRζ chain. J. Immunol. 172, 104–113 (2004).
Imai, C. et al. Chimeric receptors with 4-1BB signaling capacity provoke potent cytotoxicity against acute lymphoblastic leukemia. Leukemia 18, 676–684 (2004).
Maude, S. L. et al. Chimeric antigen receptor T cells for sustained remissions in leukemia. N. Engl. J. Med. 371, 1507–1517 (2014).
Hinrichs, C. S. & Restifo, N. P. Reassessing target antigens for adoptive T cell therapy. Nat. Biotechnol. 31, 999–1008 (2013).
Rosenberg, S. A. Finding suitable targets is the major obstacle to cancer gene therapy. Cancer Gene Ther. 21, 45–47 (2014).
Yu, J. X., Upadhaya, S., Tatake, R., Barkalow, F. & Hubbard-Lucey, V. M. Cancer cell therapies: the clinical trial landscape. Nat. Rev. Drug Discov. 19, 583–584 (2020).
Davila, M. L. et al. Efficacy and toxicity management of 19-28z CAR T cell therapy in B cell acute lymphoblastic leukemia. Sci. Transl. Med. 6, 224ra25 (2014).
Lee, D. W. et al. T cells expressing CD19 chimeric antigen receptors for acute lymphoblastic leukaemia in children and young adults: a phase 1 dose-escalation trial. Lancet 385, 517–528 (2015).
Sadelain, M., Brentjens, R., Rivière, I. & Park, J. CD19 CAR therapy for acute lymphoblastic leukemia. Am. Soc. Clin. Oncol. Educ. Book https://doi.org/10.14694/EdBook_AM.2015.35.e360 (2015).
Johnson, L. A. et al. Gene therapy with human and mouse T-cell receptors mediates cancer regression and targets normal tissues expressing cognate antigen. Blood 114, 535–546 (2009).
Parkhurst, M. R. et al. T cells targeting carcinoembryonic antigen can mediate regression of metastatic colorectal cancer but induce severe transient colitis. Mol. Ther. 19, 620–626 (2011).
Lamers, C. H. J. et al. Treatment of metastatic renal cell carcinoma with autologous T-lymphocytes genetically retargeted against carbonic anhydrase IX: first clinical experience. J. Clin. Oncol. 24, e20–e22 (2006).
Morgan, R. A. et al. Cancer regression and neurologic toxicity following anti-MAGE-A3 TCR gene therapy. J. Immunother. 36, 133–151 (2013).
Linette, G. P. et al. Cardiovascular toxicity and titin cross-reactivity of affinity-enhanced T cells in myeloma and melanoma. Blood 122, 863–871 (2013).
Cameron, B. J. et al. Identification of a titin-derived HLA-A1–presented peptide as a cross-reactive target for engineered MAGE A3–directed T cells. Sci. Transl. Med. 5, 197ra103 (2013).
Morgan, R. A. et al. Case report of a serious adverse event following the administration of T cells transduced with a chimeric antigen receptor recognizing ERBB2. Mol. Ther. 18, 843–851 (2010).
Chang, K., Pai, L. H., Batra, J. K., Pastan, I. & Willingham, M. C. Characterization of the antigen (CAK1) recognized by monoclonal antibody K1 present on ovarian cancers and normal mesothelium. Cancer Res. 52, 181–186 (1992).
Morello, A., Sadelain, M. & Adusumilli, P. S. Mesothelin-targeted CARs: driving T cells to solid tumors. Cancer Discov. 6, 133–146 (2016).
Maus, M. V. et al. T cells expressing chimeric antigen receptors can cause anaphylaxis in humans. Cancer Immunol. Res. 1, 26–31 (2013).
Beatty, G. L. et al. Mesothelin-specific chimeric antigen receptor mRNA-engineered T cells induce antitumor activity in solid malignancies. Cancer Immunol. Res. 2, 112–120 (2014).
Haas, A. R. et al. Phase I study of lentiviral-transduced chimeric antigen receptor-modified T cells recognizing mesothelin in advanced solid cancers. Mol. Ther. 27, 1919–1929 (2019).
Adusumilli, P. S. et al. Regional delivery of mesothelin-targeted CAR T cells for pleural cancers: safety and preliminary efficacy in combination with anti-PD-1 agent. J. Clin. Oncol. 37, 2511 (2019).
Annunziata, C. M. et al. Feasibility and preliminary safety and efficacy of first-in-human intraperitoneal delivery of MCY-M11, anti-human-mesothelin CAR mRNA transfected into peripheral blood mononuclear cells, for ovarian cancer and malignant peritoneal mesothelioma. J. Clin. Oncol. 38, 3014 (2020).
Chmielewski, M., Hombach, A., Heuser, C., Adams, G. P. & Abken, H. T cell activation by antibody-like immunoreceptors: increase in affinity of the single-chain fragment domain above threshold does not increase T cell activation against antigen-positive target cells but decreases selectivity. J. Immunol. 173, 7647–7653 (2004).
Liu, X. et al. Affinity-tuned ErbB2 or EGFR chimeric antigen receptor T cells exhibit an increased therapeutic index against tumors in mice. Cancer Res. 75, 3596–3607 (2015).
Caruso, H. G. et al. Tuning sensitivity of CAR to EGFR density limits recognition of normal tissue while maintaining potent antitumor activity. Cancer Res. 75, 3505–3518 (2015).
Stone, J. D., Aggen, D. H., Schietinger, A., Schreiber, H. & Kranz, D. M. A sensitivity scale for targeting T cells with chimeric antigen receptors (CARs) and bispecific T-cell Engagers (BiTEs). OncoImmunology 1, 863–873 (2012).
Posey, A. D. et al. Engineered CAR T cells targeting the cancer-associated Tn-glycoform of the membrane Mucin MUC1 control adenocarcinoma. Immunity 44, 1444–1454 (2016).
He, Y. et al. Multiple cancer-specific antigens are targeted by a chimeric antigen receptor on a single cancer cell. JCI Insight 4, e130416 (2019).
Sharma, P. et al. Structure-guided engineering of the affinity and specificity of CARs against Tn-glycopeptides. Proc. Natl Acad. Sci. USA 117, 15148–15159 (2020).
Kloss, C. C., Condomines, M., Cartellieri, M., Bachmann, M. & Sadelain, M. Combinatorial antigen recognition with balanced signaling promotes selective tumor eradication by engineered T cells. Nat. Biotechnol. 31, 71–75 (2013).
Roybal, K. T. et al. Engineering T cells with customized therapeutic response programs using synthetic notch receptors. Cell 167, 419–432.e16 (2016).
Srivastava, S. et al. Logic-gated ROR1 chimeric antigen receptor expression rescues T cell-mediated toxicity to normal tissues and enables selective tumor targeting. Cancer Cell 35, 489–503.e8 (2019).
Joseph, H. et al. SynNotch-CAR T cells overcome challenges of specificity, heterogeneity, and persistence in treating glioblastoma. Sci. Transl Med. 13, eabe7378 (2021).
Fedorov, V. D., Themeli, M. & Sadelain, M. PD-1– and CTLA-4–based inhibitory chimeric antigen receptors (iCARs) divert off-target immunotherapy responses. Sci. Transl. Med. 5, 215ra172 (2013).
Cho, J. H., Collins, J. J. & Wong, W. W. Universal chimeric antigen receptors for multiplexed and logical control of T cell responses. Cell 173, 1426–1438.e11 (2018).
Chowdhury, D. & Lieberman, J. Death by a thousand cuts: granzyme pathways of programmed cell death. Annu. Rev. Immunol. 26, 389–420 (2008).
Ho, P., Ede, C. & Chen, Y. Y. Modularly constructed synthetic granzyme B molecule enables interrogation of intracellular proteases for targeted cytotoxicity. ACS Synth. Biol. 6, 1484–1495 (2017).
Höckel, M. & Vaupel, P. Tumor hypoxia: definitions and current clinical, biologic, and molecular aspects. J. Natl Cancer Inst. 93, 266–276 (2001).
Ede, C., Chen, X., Lin, M.-Y. & Chen, Y. Y. Quantitative analyses of core promoters enable precise engineering of regulated gene expression in mammalian cells. ACS Synth. Biol. 5, 395–404 (2016).
Juillerat, A. et al. An oxygen sensitive self-decision making engineered CAR T-cell. Sci. Rep. 7, 39833 (2017).
Brennan, C. W. et al. The somatic genomic landscape of glioblastoma. Cell 155, 462–477 (2013).
Johnson, L. A. et al. Rational development and characterization of humanized anti–EGFR variant III chimeric antigen receptor T cells for glioblastoma. Sci. Transl. Med. 7, 275ra22 (2015).
Nathanson, D. A. et al. Targeted therapy resistance mediated by dynamic regulation of extrachromosomal mutant EGFR DNA. Science 343, 72–76 (2014).
Snuderl, M. et al. Mosaic amplification of multiple receptor tyrosine kinase genes in glioblastoma. Cancer Cell 20, 810–817 (2011).
Majzner, R. G. & Mackall, C. L. Tumor antigen escape from CAR T-cell therapy. Cancer Discov. 8, 1219–1226 (2018).
Zah, E., Lin, M.-Y., Silva-Benedict, A., Jensen, M. C. & Chen, Y. Y. T cells expressing CD19/CD20 bispecific chimeric antigen receptors prevent antigen escape by malignant B cells. Cancer Immunol. Res. 4, 498–508 (2016).
Qin, H. et al. Preclinical development of bivalent chimeric antigen receptors targeting both CD19 and CD22. Mol. Ther.Oncolytics 11, 127–137 (2018).
Zah, E. et al. Systematically optimized BCMA/CS1 bispecific CAR-T cells robustly control heterogeneous multiple myeloma. Nat. Commun. 11, 2283 (2020).
Bielamowicz, K. et al. Trivalent CAR T cells overcome interpatient antigenic variability in glioblastoma. Neuro Oncol. 20, 506–518 (2018).
Bos, T. J., De Bruyne, E., Van Lint, S., Heirman, C. & Vanderkerken, K. Large double copy vectors are functional but show a size-dependent decline in transduction efficiency. J. Biotechnol. 150, 37–40 (2010).
Zhang, T., Lemoi, B. A. & Sentman, C. L. Chimeric NK-receptor–bearing T cells mediate antitumor immunotherapy. Blood 106, 1544–1551 (2005).
Lyons, S. A., O’Neal, J. & Sontheimer, H. Chlorotoxin, a scorpion-derived peptide, specifically binds to gliomas and tumors of neuroectodermal origin. Glia 39, 162–173 (2002).
Wang, D. et al. Chlorotoxin-directed CAR T cells for specific and effective targeting of glioblastoma. Sci. Transl. Med. 12, eaaw2672 (2020). This study demonstrates efficient eradication of heterogeneous GBM tumours using T cells engineered with CARs that have a single, rather than multiple, ligand-binding domain.
Wing, A. et al. Improving CART-cell therapy of solid tumors with oncolytic virus–driven production of a bispecific T-cell engager. Cancer Immunol. Res. 6, 605–616 (2018).
Choi, B. D. et al. CAR-T cells secreting BiTEs circumvent antigen escape without detectable toxicity. Nat. Biotechnol. 37, 1049–1058 (2019).
Park, A. K. et al. Effective combination immunotherapy using oncolytic viruses to deliver CAR targets to solid tumors. Sci. Transl. Med. 12, eaaz1863 (2020).
Chapuis, A. G. et al. Transferred WT1-reactive CD8+ T cells can mediate antileukemic activity and persist in post-transplant patients. Sci. Transl. Med. 5, 174ra27 (2013).
Chapuis, A. G. et al. T cell receptor gene therapy targeting WT1 prevents acute myeloid leukemia relapse post-transplant. Nat. Med. 25, 1064–1072 (2019).
Kageyama, S. et al. Adoptive transfer of MAGE-A4 T-cell receptor gene-transduced lymphocytes in patients with recurrent esophageal cancer. Clin. Cancer Res. 21, 2268–2277 (2015).
Maus, M. V. et al. An MHC-restricted antibody-based chimeric antigen receptor requires TCR-like affinity to maintain antigen specificity. Mol. Ther. Oncolytics 3, 1–9 (2016).
Akahori, Y. et al. Antitumor activity of CAR-T cells targeting the intracellular oncoprotein WT1 can be enhanced by vaccination. Blood 132, 1134–1145 (2018).
Schumacher, T. N. & Schreiber, R. D. Neoantigens in cancer immunotherapy. Science 348, 69–74 (2015).
Nielsen, M. et al. NetMHCpan, a method for quantitative predictions of peptide binding to any HLA-A and -B locus protein of known sequence. PLoS ONE 2, e796 (2007).
Fritsch, E. F. et al. HLA-binding properties of tumor neoepitopes in humans. Cancer Immunol. Res. 2, 522–529 (2014).
Peng, S. et al. Sensitive detection and analysis of neoantigen-specific T cell populations from tumors and blood. Cell Rep. 28, 2728–2738.e7 (2019).
Carreno, B. M. et al. A dendritic cell vaccine increases the breadth and diversity of melanoma neoantigen-specific T cells. Science 348, 803–808 (2015).
Ott, P. A. et al. An immunogenic personal neoantigen vaccine for patients with melanoma. Nature 547, 217–221 (2017).
Ahmadzadeh, M. et al. Tumor antigen–specific CD8 T cells infiltrating the tumor express high levels of PD-1 and are functionally impaired. Blood 114, 1537–1544 (2009).
Klebanoff, C. A., Gattinoni, L. & Restifo, N. P. Sorting through subsets: which T-cell populations mediate highly effective adoptive immunotherapy? J. Immunother. 35, 651–660 (2012).
Yamamoto, T. N., Kishton, R. J. & Restifo, N. P. Developing neoantigen-targeted T cell–based treatments for solid tumors. Nat. Med. 25, 1488–1499 (2019).
Alexandrov, L. B. et al. Signatures of mutational processes in human cancer. Nature 500, 415–421 (2013).
Lu, Y.-C. et al. Efficient identification of mutated cancer antigens recognized by T cells associated with durable tumor regressions. Clin. Cancer Res. 20, 3401–3410 (2014).
Linnemann, C. et al. High-throughput epitope discovery reveals frequent recognition of neo-antigens by CD4+ T cells in human melanoma. Nat. Med. 21, 81–85 (2015).
Nagarsheth, N., Wicha, M. S. & Zou, W. Chemokines in the cancer microenvironment and their relevance in cancer immunotherapy. Nat. Rev. Immunol. 17, 559–572 (2017).
Valkenburg, K. C., de Groot, A. E. & Pienta, K. J. Targeting the tumour stroma to improve cancer therapy. Nat. Rev. Clin. Oncol. 15, 366–381 (2018).
Lanitis, E., Irving, M. & Coukos, G. Targeting the tumor vasculature to enhance T cell activity. Curr. Opin. Immunol. 33, 55–63 (2015).
Huang, Y. et al. Improving immune–vascular crosstalk for cancer immunotherapy. Nat. Rev. Immunol. 18, 195–203 (2018).
Craddock, J. A. et al. Enhanced tumor trafficking of GD2 chimeric antigen receptor T cells by expression of the chemokine receptor CCR2b. J. Immunother. 33, 780–788 (2010).
Moon, E. K. et al. Expression of a functional CCR2 receptor enhances tumor localization and tumor eradication by retargeted human T cells expressing a mesothelin-specific chimeric antibody receptor. Clin. Cancer Res. 17, 4719–4730 (2011).
Adachi, K. et al. IL-7 and CCL19 expression in CAR-T cells improves immune cell infiltration and CAR-T cell survival in the tumor. Nat. Biotechnol. 36, 346–351 (2018).
Gunderson, A. J. et al. TGFβ suppresses CD8+ T cell expression of CXCR3 and tumor trafficking. Nat. Commun. 11, 1749 (2020).
Mariathasan, S. et al. TGFβ attenuates tumour response to PD-L1 blockade by contributing to exclusion of T cells. Nature 554, 544–548 (2018).
Tauriello, D. V. F. et al. TGFβ drives immune evasion in genetically reconstituted colon cancer metastasis. Nature 554, 538–543 (2018).
Chakravarthy, A., Khan, L., Bensler, N. P., Bose, P. & De Carvalho, D. D. TGF-β-associated extracellular matrix genes link cancer-associated fibroblasts to immune evasion and immunotherapy failure. Nat. Commun. 9, 4692 (2018).
Kakarla, S. et al. Antitumor effects of chimeric receptor engineered human T cells directed to tumor stroma. Mol. Ther. 21, 1611–1620 (2013).
Wang, L.-C. S. et al. Targeting fibroblast activation protein in tumor stroma with chimeric antigen receptor T cells can inhibit tumor growth and augment host immunity without severe toxicity. Cancer Immunol. Res. 2, 154–166 (2014).
Tran, E. et al. Immune targeting of fibroblast activation protein triggers recognition of multipotent bone marrow stromal cells and cachexia. J. Exp. Med. 210, 1125–1135 (2013).
Anderton, M. J. et al. Induction of heart valve lesions by small-molecule ALK5 inhibitors. Toxicol. Pathol. 39, 916–924 (2011).
Hanley, C. J. et al. Targeting the myofibroblastic cancer-associated fibroblast phenotype through inhibition of NOX4. J. Natl Cancer Inst. 110, 109–120 (2018).
Ford, K. et al. NOX4 inhibition potentiates immunotherapy by overcoming cancer-associated fibroblast-mediated CD8 T-cell exclusion from tumours. Cancer Res. 80, 1846–1860 (2020).
Caruana, I. et al. Heparanase promotes tumor infiltration and antitumor activity of CAR-redirected T lymphocytes. Nat. Med. 21, 524–529 (2015).
Newick, K. et al. Augmentation of CAR T-cell trafficking and antitumor efficacy by blocking protein kinase A localization. Cancer Immunol. Res. 4, 541–551 (2016).
Muller, W. A. Mechanisms of leukocyte transendothelial migration. Annu. Rev. Pathol. 6, 323–344 (2011).
Adusumilli, P. S. et al. Regional delivery of mesothelin-targeted CAR T cell therapy generates potent and long-lasting CD4-dependent tumor immunity. Sci. Transl. Med. 6, 261ra151 (2014).
Saied, A. et al. Neutrophil:lymphocyte ratios and serum cytokine changes after hepatic artery chimeric antigen receptor-modified T-cell infusions for liver metastases. Cancer Gene Ther. 21, 457–462 (2014).
Katz, S. C. et al. Phase I hepatic immunotherapy for metastases study of intra-arterial chimeric antigen receptor–modified T-cell therapy for CEA+ liver metastases. Clin. Cancer Res. 21, 3149–3159 (2015).
Katz, S. C. et al. HITM-SIR: phase Ib trial of intraarterial chimeric antigen receptor T-cell therapy and selective internal radiation therapy for CEA+ liver metastases. Cancer Gene Ther. 27, 341–355 (2020).
Brown, C. E. et al. Optimization of IL13Rα2-targeted chimeric antigen receptor T cells for improved anti-tumor efficacy against glioblastoma. Mol. Ther. 26, 31–44 (2018).
Theruvath, J. et al. Locoregionally administered B7-H3-targeted CAR T cells for treatment of atypical teratoid/rhabdoid tumors. Nat. Med. 26, 712–719 (2020). This study systematically compares various CAR-T cell delivery routes to demonstrate that locoregional administration produces an optimal therapeutic response.
Stephan, S. B. et al. Biopolymer implants enhance the efficacy of adoptive T-cell therapy. Nat. Biotechnol. 33, 97–101 (2015).
Smith, T. T. et al. Biopolymers codelivering engineered T cells and STING agonists can eliminate heterogeneous tumors. J. Clin. Invest. 127, 2176–2191 (2017). This study takes a multi-pronged, interdisciplinary approach to effectively deliver CAR T cells with enhanced potency against solid tumours by co-administration with STING agonists in a biopolymer scaffold.
Coon, M. E., Stephan, S. B., Gupta, V., Kealey, C. P. & Stephan, M. T. Nitinol thin films functionalized with CAR-T cells for the treatment of solid tumours. Nat. Biomed. Eng. 4, 195–206 (2020).
Gabrilovich, D. I., Ostrand-Rosenberg, S. & Bronte, V. Coordinated regulation of myeloid cells by tumours. Nat. Rev. Immunol. 12, 253–268 (2012).
Quail, D. F. & Joyce, J. A. Microenvironmental regulation of tumor progression and metastasis. Nat. Med. 19, 1423–1437 (2013).
Binnewies, M. et al. Understanding the tumor immune microenvironment (TIME) for effective therapy. Nat. Med. 24, 541–550 (2018).
Bollard, C. M. et al. Adapting a transforming growth factor β-related tumor protection strategy to enhance antitumor immunity. Blood 99, 3179–3187 (2002).
Roth, T. L. et al. Pooled knockin targeting for genome engineering of cellular immunotherapies. Cell 181, 728–744.e21 (2020). This study employs a transgene knock-in, library-screening approach to identify synthetic receptors that confer enhanced T cell function against solid tumours.
Chang, Z. L. et al. Rewiring T-cell responses to soluble factors with chimeric antigen receptors. Nat. Chem. Biol. 14, 317–324 (2018).
Hou, A. J., Chang, Z. L., Lorenzini, M. H., Zah, E. & Chen, Y. Y. TGF-β–responsive CAR-T cells promote anti-tumor immune function. Bioeng. Transl. Med. 3, 75–86 (2018).
Chang, Z. L., Hou, A. J. & Chen, Y. Y. Engineering primary T cells with chimeric antigen receptors for rewired responses to soluble ligands. Nat. Protoc. 15, 1507–1524 (2020).
Kloss, C. C. et al. Dominant-negative TGF-β receptor enhances PSMA-targeted human CAR T cell proliferation and augments prostate cancer eradication. Mol. Ther. 26, 1855–1866 (2018).
Wilkie, S. et al. Selective expansion of chimeric antigen receptor-targeted T-cells with potent effector function using interleukin-4. J. Biol. Chem. 285, 25538–25544 (2010).
Leen, A. M. et al. Reversal of tumor immune inhibition using a chimeric cytokine receptor. Mol. Ther. 22, 1211–1220 (2014).
Mohammed, S. et al. Improving chimeric antigen receptor-modified T cell function by reversing the immunosuppressive tumor microenvironment of pancreatic cancer. Mol. Ther. 25, 249–258 (2017).
Sukumaran, S. et al. Enhancing the potency and specificity of engineered T cells for cancer treatment. Cancer Discov. 8, 972–987 (2018).
Cherkassky, L. et al. Human CAR T cells with cell-intrinsic PD-1 checkpoint blockade resist tumor-mediated inhibition. J. Clin. Invest. 126, 3130–3144 (2016).
Prosser, M. E., Brown, C. E., Shami, A. F., Forman, S. J. & Jensen, M. C. Tumor PD-L1 co-stimulates primary human CD8+ cytotoxic T cells modified to express a PD1:CD28 chimeric receptor. Mol. Immunol. 51, 263–272 (2012).
Liu, X. et al. A chimeric switch-receptor targeting PD1 augments the efficacy of second generation CAR T-cells in advanced solid tumors. Cancer Res. 76, 1578–1590 (2016).
Yamamoto, T. N. et al. T cells genetically engineered to overcome death signaling enhance adoptive cancer immunotherapy. J. Clin. Invest. 129, 1551–1565 (2019).
Chmielewski, M., Kopecky, C., Hombach, A. A. & Abken, H. IL-12 release by engineered T cells expressing chimeric antigen receptors can effectively muster an antigen-independent macrophage response on tumor cells that have shut down tumor antigen expression. Cancer Res. 71, 5697–5706 (2011).
Pegram, H. J. et al. Tumor-targeted T cells modified to secrete IL-12 eradicate systemic tumors without need for prior conditioning. Blood 119, 4133–4141 (2012).
Hu, B. et al. Augmentation of antitumor immunity by human and mouse CAR T cells secreting IL-18. Cell Rep. 20, 3025–3033 (2017).
Avanzi, M. P. et al. Engineered tumor-targeted T cells mediate enhanced anti-tumor efficacy both directly and through activation of the endogenous immune system. Cell Rep. 23, 2130–2141 (2018).
Ma, X. et al. Interleukin-23 engineering improves CAR T cell function in solid tumors. Nat. Biotechnol. 38, 448–459 (2020).
Cassetta, L. & Kitamura, T. Targeting tumor-associated macrophages as a potential strategy to enhance the response to immune checkpoint inhibitors. Front. Cell Dev. Biol. 6, 38 (2018).
Strauss, L. et al. Targeted deletion of PD-1 in myeloid cells induces antitumor immunity. Sci. Immunol. 5, eaay1863 (2020).
Stromnes, I. M. et al. Differential effects of depleting versus programming tumor-associated macrophages on engineered T cells in pancreatic ductal adenocarcinoma. Cancer Immunol. Res. 7, 977–989 (2019). This study demonstrates the advantage of myeloid-cell reprogramming over depletion in combination with adoptive T cell transfer.
Parihar, R. et al. NK cells expressing a chimeric activating receptor eliminate MDSCs and rescue impaired CAR-T cell activity against solid tumors. Cancer Immunol. Res. 7, 363–375 (2019).
Parisi, G. et al. Persistence of adoptively transferred T cells with a kinetically engineered IL-2 receptor agonist. Nat. Commun. 11, 660 (2020).
Sun, Z. et al. A next-generation tumor-targeting IL-2 preferentially promotes tumor-infiltrating CD8+ T-cell response and effective tumor control. Nat. Commun. 10, 3874 (2019).
Sockolosky, J. T. et al. Selective targeting of engineered T cells using orthogonal IL-2 cytokine-receptor complexes. Science 359, 1037–1042 (2018).
Neubert, N. J. et al. T cell-induced CSF1 promotes melanoma resistance to PD1 blockade. Sci. Transl. Med. 10, eaan3311 (2018).
O’Rourke, D. M. et al. A single dose of peripherally infused EGFRvIII-directed CAR T cells mediates antigen loss and induces adaptive resistance in patients with recurrent glioblastoma. Sci. Transl. Med. 9, eaaa0984 (2017).
Sampson, J. H. et al. EGFRvIII mCAR-modified T-cell therapy cures mice with established intracerebral glioma and generates host immunity against tumor-antigen loss. Clin. Cancer Res. 20, 972–984 (2014).
Pituch, K. C. et al. Adoptive transfer of IL13Rα2-specific chimeric antigen receptor T cells creates a pro-inflammatory environment in glioblastoma. Mol. Ther. 26, 986–995 (2018).
Ma, L. et al. Enhanced CAR-T cell activity against solid tumors by vaccine boosting through the chimeric receptor. Science 365, 162–168 (2019).
Lai, J. et al. Adoptive cellular therapy with T cells expressing the dendritic cell growth factor Flt3L drives epitope spreading and antitumor immunity. Nat. Immunol. 21, 914–926 (2020). This study presents a novel strategy to engineer CAR T cells that recruit DCs to stimulate endogenous antitumour immunity.
Liu, Y. et al. Gasdermin E-mediated target cell pyroptosis by CAR T cells triggers cytokine release syndrome. Sci. Immunol. 5, eaax7969 (2020). This study demonstrates that CAR T cells can induce pyroptosis in target tumour cells, and that pyroptosis is directly correlated with CRS-related toxicities and may contribute to the recruitment of an endogenous antitumour immune response.
Zhou, Z. et al. Granzyme A from cytotoxic lymphocytes cleaves GSDMB to trigger pyroptosis in target cells. Science 368, eaaz7548 (2020).
Wang, Y. et al. Chemotherapy drugs induce pyroptosis through caspase-3 cleavage of a gasdermin. Nature 547, 99–103 (2017).
Wang, Q. et al. A bioorthogonal system reveals antitumour immune function of pyroptosis. Nature 579, 421–426 (2020).
Pavlova, N. N. & Thompson, C. B. The emerging hallmarks of cancer metabolism. Cell Metab. 23, 27–47 (2016).
Heiden, M. G. V., Cantley, L. C. & Thompson, C. B. Understanding the warburg effect: the metabolic requirements of cell proliferation. Science 324, 1029–1033 (2009).
Chang, C.-H. et al. Metabolic competition in the tumor microenvironment is a driver of cancer progression. Cell 162, 1229–1241 (2015).
Menk, A. V. et al. Early TCR signaling induces rapid aerobic glycolysis enabling distinct acute T cell effector functions. Cell Rep. 22, 1509–1521 (2018).
Chang, C.-H. et al. Posttranscriptional control of T cell effector function by aerobic glycolysis. Cell 153, 1239–1251 (2013).
Ho, P.-C. et al. Phosphoenolpyruvate is a metabolic checkpoint of anti-tumor T cell responses. Cell 162, 1217–1228 (2015).
Qiu, J. et al. Acetate promotes T cell effector function during glucose restriction. Cell Rep. 27, 2063–2074.e5 (2019).
Renner, K. et al. Restricting glycolysis preserves T cell effector functions and augments checkpoint therapy. Cell Rep. 29, 135–150.e9 (2019).
Cascone, T. et al. Increased tumor glycolysis characterizes immune resistance to adoptive T cell therapy. Cell Metab. 27, 977–987.e4 (2018).
Bengsch, B. et al. Bioenergetic insufficiencies due to metabolic alterations regulated by the inhibitory receptor PD-1 are an early driver of CD8+ T cell exhaustion. Immunity 45, 358–373 (2016).
Fisicaro, P. et al. Targeting mitochondrial dysfunction can restore antiviral activity of exhausted HBV-specific CD8 T cells in chronic hepatitis B. Nat. Med. 23, 327–336 (2017).
Dumauthioz, N. et al. Enforced PGC-1α expression promotes CD8 T cell fitness, memory formation and antitumor immunity. Cell. Mol. Immunol. https://doi.org/10.1038/s41423-020-0365-3 (2020).
Ligtenberg, M. A. et al. Coexpressed catalase protects chimeric antigen receptor–redirected t cells as well as bystander cells from oxidative stress–induced loss of antitumor activity. J. Immunol. 196, 759–766 (2016).
Vardhana, S. A. et al. Impaired mitochondrial oxidative phosphorylation limits the self-renewal of T cells exposed to persistent antigen. Nat. Immunol. 21, 1022–1033 (2020). This study highlights the mechanisms underlying mitochondrial metabolic stresses caused by chronic T cell stimulation and provides a solution to remedy the metabolic and effector T cell dysfunction.
Gemta, L. F. et al. Impaired enolase 1 glycolytic activity restrains effector functions of tumor-infiltrating CD8+ T cells. Sci. Immunol. 4, eaap9520 (2019). This study pinpoints enolase 1 as a key mediator of glycolytic repression in CD8+ TILs, providing a novel mechanism towards understanding metabolic dysfunction in TILs and an accompanying solution.
Chakraborty, P. et al. Pro-survival lipid sphingosine-1-phosphate metabolically programs T cells to limit anti-tumor activity. Cell Rep. 28, 1879–1893.e7 (2019).
O’Sullivan, D. et al. Memory CD8+ T cells use cell-intrinsic lipolysis to support the metabolic programming necessary for development. Immunity 41, 75–88 (2014).
Mellor, A. L. & Munn, D. H. Ido expression by dendritic cells: tolerance and tryptophan catabolism. Nat. Rev. Immunol. 4, 762–774 (2004).
Li, H. et al. Metabolomic adaptations and correlates of survival to immune checkpoint blockade. Nat. Commun. 10, 4346 (2019).
Long, G. V. et al. Epacadostat plus pembrolizumab versus placebo plus pembrolizumab in patients with unresectable or metastatic melanoma (ECHO-301/KEYNOTE-252): a phase 3, randomised, double-blind study. Lancet Oncol. 20, 1083–1097 (2019).
Triplett, T. A. et al. Reversal of indoleamine 2,3-dioxygenase–mediated cancer immune suppression by systemic kynurenine depletion with a therapeutic enzyme. Nat. Biotechnol. 36, 758–764 (2018).
Beavis, P. A., Stagg, J., Darcy, P. K. & Smyth, M. J. CD73: a potent suppressor of antitumor immune responses. Trends Immunol. 33, 231–237 (2012).
Zhang, B. et al. High expression of CD39/ENTPD1 in malignant epithelial cells of human rectal adenocarcinoma. Tumor Biol. 36, 9411–9419 (2015).
Leone, R. D. & Emens, L. A. Targeting adenosine for cancer immunotherapy. J. Immunother. Cancer 6, 57 (2018).
Beavis, P. A. et al. Targeting the adenosine 2A receptor enhances chimeric antigen receptor T cell efficacy. J. Clin. Invest. 127, 929–941 (2017).
Fischer, K. et al. Inhibitory effect of tumor cell-derived lactic acid on human T cells. Blood 109, 3812–3819 (2007).
Brand, A. et al. LDHA-associated lactic acid production blunts tumor immunosurveillance by T and NK cells. Cell Metab. 24, 657–671 (2016).
Angelin, A. et al. Foxp3 reprograms T cell metabolism to function in low-glucose, high-lactate environments. Cell Metab. 25, 1282–1293.e7 (2017).
Colegio, O. R. et al. Functional polarization of tumour-associated macrophages by tumour-derived lactic acid. Nature 513, 559–563 (2014).
Calcinotto, A. et al. Modulation of microenvironment acidity reverses anergy in human and murine tumor-infiltrating T lymphocytes. Cancer Res. 72, 2746–2756 (2012).
Pilon-Thomas, S. et al. Neutralization of tumor acidity improves antitumor responses to immunotherapy. Cancer Res. 76, 1381–1390 (2016).
Yang, W. et al. Potentiating the antitumour response of CD8+ T cells by modulating cholesterol metabolism. Nature 531, 651–655 (2016).
Patel, C. H. & Powell, J. D. Targeting T cell metabolism to regulate T cell activation, differentiation and function in disease. Curr. Opin. Immunol. 46, 82–88 (2017).
McLane, L. M., Abdel-Hakeem, M. S. & Wherry, E. J. CD8 T cell exhaustion during chronic viral infection and cancer. Annu. Rev. Immunol. 37, 457–495 (2019).
Pauken, K. E. et al. Epigenetic stability of exhausted T cells limits durability of reinvigoration by PD-1 blockade. Science 354, 1160–1165 (2016).
Satpathy, A. T. et al. Massively parallel single-cell chromatin landscapes of human immune cell development and intratumoral T cell exhaustion. Nat. Biotechnol. 37, 925–936 (2019).
Khan, O. et al. TOX transcriptionally and epigenetically programs CD8+ T cell exhaustion. Nature 571, 211–218 (2019).
Scott, A. C. et al. TOX is a critical regulator of tumour-specific T cell differentiation. Nature 571, 270–274 (2019).
Yao, C. et al. Single-cell RNA-seq reveals TOX as a key regulator of CD8+ T cell persistence in chronic infection. Nat. Immunol. 20, 890–901 (2019).
Alfei, F. et al. TOX reinforces the phenotype and longevity of exhausted T cells in chronic viral infection. Nature 571, 265–269 (2019).
Chen, J. et al. NR4A transcription factors limit CAR T cell function in solid tumours. Nature 567, 530–534 (2019).
LaFleur, M. W. et al. PTPN2 regulates the generation of exhausted CD8+ T cell subpopulations and restrains tumor immunity. Nat. Immunol. 20, 1335–1347 (2019).
Wiede, F. et al. PTPN2 phosphatase deletion in T cells promotes anti-tumour immunity and CAR T-cell efficacy in solid tumours. EMBO J. 39, e103637 (2020).
Chen, Z. et al. TCF-1-centered transcriptional network drives an effector versus exhausted CD8 T cell-fate decision. Immunity 51, 840–855.e5 (2019).
Siddiqui, I. et al. Intratumoral Tcf1+PD-1+CD8+ T cells with stem-like properties promote tumor control in response to vaccination and checkpoint blockade immunotherapy. Immunity 50, 195–211.e10 (2019).
Beltra, J.-C. et al. Developmental relationships of four exhausted CD8+ T cell subsets reveals underlying transcriptional and epigenetic landscape control mechanisms. Immunity 52, 825–841.e8 (2020).
Lynn, R. C. et al. c-Jun overexpression in CAR T cells induces exhaustion resistance. Nature 576, 293–300 (2019). This study identifies novel epigenetic and genetic features of CAR-T cell exhaustion and provides a CAR-T cell engineering solution that increases CAR-T cell resistance to exhaustion.
Feucht, J. et al. Calibration of CAR activation potential directs alternative T cell fates and therapeutic potency. Nat. Med. 25, 82–88 (2019). This study provides an elegant engineering strategy, through rational modulation of CD3ζ signalling, to balance strong antitumour responses with CAR-T cell longevity.
Rafiq, S. et al. Targeted delivery of a PD-1-blocking scFv by CAR-T cells enhances anti-tumor efficacy in vivo. Nat. Biotechnol. 36, 847–856 (2018).
Grosser, R., Cherkassky, L., Chintala, N. & Adusumilli, P. S. Combination immunotherapy with CAR T cells and checkpoint blockade for the treatment of solid tumors. Cancer Cell 36, 471–482 (2019).
Brentjens, R. J. et al. Safety and persistence of adoptively transferred autologous CD19-targeted T cells in patients with relapsed or chemotherapy refractory B-cell leukemias. Blood 118, 4817–4828 (2011).
Kochenderfer, J. N. et al. B-cell depletion and remissions of malignancy along with cytokine-associated toxicity in a clinical trial of anti-CD19 chimeric-antigen-receptor-transduced T cells. Blood 119, 2709–2720 (2012).
Locke, F. L. et al. Phase 1 results of ZUMA-1: a multicenter study of KTE-C19 anti-CD19 CAR T cell therapy in refractory aggressive lymphoma. Mol. Ther. 25, 285–295 (2017).
Ali, S. A. et al. T cells expressing an anti-B-cell maturation antigen chimeric antigen receptor cause remissions of multiple myeloma. Blood 128, 1688–1700 (2016).
Cohen, A. D. et al. Safety and efficacy of B-cell maturation antigen (BCMA)-specific chimeric antigen receptor T cells (CART-BCMA) with cyclophosphamide conditioning for refractory multiple myeloma (MM). Blood 130, 505 (2017).
Brudno, J. N. et al. T cells genetically modified to express an anti-B-cell maturation antigen chimeric antigen receptor cause remissions of poor-prognosis relapsed multiple myeloma. J. Clin. Oncol. 36, 2267–2280 (2018).
Raje, N. et al. Anti-BCMA CAR T-cell therapy bb2121 in relapsed or refractory multiple myeloma. N. Engl. J. Med. 380, 1726–1737 (2019).
Lee, D. W. et al. Current concepts in the diagnosis and management of cytokine release syndrome. Blood 124, 188–195 (2014).
Sterner, R. M. et al. GM-CSF inhibition reduces cytokine release syndrome and neuroinflammation but enhances CAR-T cell function in xenografts. Blood 133, 697–709 (2019).
Giavridis, T. et al. CAR T cell-induced cytokine release syndrome is mediated by macrophages and abated by IL-1 blockade. Nat. Med. 24, 731–738 (2018).
Norelli, M. et al. Monocyte-derived IL-1 and IL-6 are differentially required for cytokine-release syndrome and neurotoxicity due to CAR T cells. Nat. Med. 24, 739–748 (2018).
Tan, A. H. J., Vinanica, N. & Campana, D. Chimeric antigen receptor–T cells with cytokine neutralizing capacity. Blood Adv. 4, 1419–1431 (2020).
Brown, C. E. et al. Regression of glioblastoma after chimeric antigen receptor T-cell therapy. N. Engl. J. Med. 375, 2561–2569 (2016).
Mount, C. W. et al. Potent antitumor efficacy of anti-GD2 CAR T cells in H3-K27M+ diffuse midline gliomas. Nat. Med. 24, 572–579 (2018).
Gust, J. et al. Endothelial activation and blood–brain barrier disruption in neurotoxicity after adoptive immunotherapy with CD19 CAR-T cells. Cancer Discov. 7, 1404–1419 (2017).
Neelapu, S. S. et al. Chimeric antigen receptor T-cell therapy — assessment and management of toxicities. Nat. Rev. Clin. Oncol. 15, 47–62 (2018).
Parker, K. R. et al. Single-cell analyses identify brain mural cells expressing CD19 as potential off-tumor targets for CAR-T immunotherapies. Cell 183, 126–142.e17 (2020).
Di Stasi, A. et al. Inducible apoptosis as a safety switch for adoptive cell therapy. N. Engl. J. Med. 365, 1673–1683 (2011).
Bonini, C. et al. HSV-TK gene transfer into donor lymphocytes for control of allogeneic graft-versus-leukemia. Science 276, 1719–1724 (1997).
Berger, C., Flowers, M. E., Warren, E. H. & Riddell, S. R. Analysis of transgene-specific immune responses that limit the in vivo persistence of adoptively transferred HSV-TK-modified donor T cells after allogeneic hematopoietic cell transplantation. Blood 107, 2294–2302 (2006).
Ciceri, F. et al. Infusion of suicide-gene-engineered donor lymphocytes after family haploidentical haemopoietic stem-cell transplantation for leukaemia (the TK007 trial): a non-randomised phase I–II study. Lancet Oncol. 10, 489–500 (2009).
Griffioen, M. et al. Retroviral transfer of human CD20 as a suicide gene for adoptive T-cell therapy. Haematologica 94, 1316–1320 (2009).
Wang, X. et al. A transgene-encoded cell surface polypeptide for selection, in vivo tracking, and ablation of engineered cells. Blood 118, 1255–1263 (2011).
Mestermann, K. et al. The tyrosine kinase inhibitor dasatinib acts as a pharmacologic on/off switch for CAR T cells. Sci. Transl. Med. 11, eaau5907 (2019). This study introduces a novel method to rapidly and reversibly inhibit CAR-T cell activity without the need to introduce additional genetic components.
Juillerat, A. et al. Modulation of chimeric antigen receptor surface expression by a small molecule switch. BMC Biotechnol. 19, 44 (2019).
Weber, E. W. et al. Transient “rest” induces functional reinvigoration and epigenetic remodeling in exhausted CAR-T cells. Preprint at bioRxiv https://doi.org/10.1101/2020.01.26.920496 (2020).
Giordano-Attianese, G. et al. A computationally designed chimeric antigen receptor provides a small-molecule safety switch for T-cell therapy. Nat. Biotechnol. 38, 426–432 (2020).
Foster, A. E. et al. Regulated expansion and survival of chimeric antigen receptor-modified T cells using small molecule-dependent inducible MyD88/CD40. Mol. Ther. 25, 2176–2188 (2017).
Narayanan, P. et al. A composite MyD88/CD40 switch synergistically activates mouse and human dendritic cells for enhanced antitumor efficacy. J. Clin. Invest. 121, 1524–1534 (2011).
Harris, D. T. & Kranz, D. M. Adoptive T cell therapies: a comparison of T cell receptors and chimeric antigen receptors. Trends Pharmacol. Sci. 37, 220–230 (2016).
Wu, L., Wei, Q., Brzostek, J. & Gascoigne, N. R. J. Signaling from T cell receptors (TCRs) and chimeric antigen receptors (CARs) on T cells. Cell. Mol. Immunol. 17, 600–612 (2020).
Harris, D. T. et al. Comparison of T cell activities mediated by human TCRs and CARs that use the same recognition domains. J. Immunol. 200, 1088–1100 (2018).
Oren, R. et al. Functional comparison of engineered T cells carrying a native TCR versus TCR-like antibody-based chimeric antigen receptors indicates affinity/avidity thresholds. J. Immunol. 193, 5733–5743 (2014).
Xu, Y. et al. A novel antibody-TCR (AbTCR) platform combines Fab-based antigen recognition with gamma/delta-TCR signaling to facilitate T-cell cytotoxicity with low cytokine release. Cell Discov. 4, 1–13 (2018).
Baeuerle, P. A. et al. Synthetic TRuC receptors engaging the complete T cell receptor for potent anti-tumor response. Nat. Commun. 10, 2087 (2019).
Helsen, C. W. et al. The chimeric TAC receptor co-opts the T cell receptor yielding robust anti-tumor activity without toxicity. Nat. Commun. 9, 3049 (2018).
Seo, H. et al. TOX and TOX2 transcription factors cooperate with NR4A transcription factors to impose CD8+ T cell exhaustion. Proc. Natl. Acad. Sci. USA 116, 12410–12415 (2019).
Stadtmauer, E. A. et al. CRISPR-engineered T cells in patients with refractory cancer. Science 367, eaba7365 (2020).
Wei, J. et al. Targeting REGNASE-1 programs long-lived effector T cells for cancer therapy. Nature 576, 471–476 (2019).
Gurusamy, D. et al. Multi-phenotype CRISPR-Cas9 screen identifies p38 kinase as a target for adoptive immunotherapies. Cancer Cell 37, 818–833.e9 (2020).
A.J.H. was supported by the Mark Foundation (grant to Y.Y.C.) and L.C.C. was supported by the National Science Foundation (grant to Y.Y.C.).
Y.Y.C. and A.J.H. declare competing financial interests in the form of patent applications whose value may be affected by the publication of this work. L.C.C. declares no competing interests.
Peer review information
Nature Reviews Drug Discovery thanks A. Okal, J. Maher and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
- T cell exhaustion
An evolving term that broadly describes a state of T cell hypofunctionality, characterized by distinct epigenetic, metabolic and phenotypic signatures, as a consequence of chronic stimulation.
- B cell aplasia
Depletion of healthy B cells in a patient receiving CAR-T cells targeting pan-B cell markers.
- Mesothelial cells
Cells that line internal body cavities, including organs such as the heart and lungs.
- Boolean AND-gate logic
A logical computation in which both condition ‘A’ AND condition ‘B’ must be met for the outcome to be true.
- Boolean AND-NOT-gate
A logical computation in which condition ‘A’ must be true AND condition ‘B’ must NOT be true for the outcome to be true.
- Bispecific T cell engager
(BiTE). A bispecific antibody consisting of a tumour-targeting antibody and a T cell-stimulating, anti-CD3 antibody.
- Immunoreceptor tyrosine-based activation motifs
Conserved sequences found in the cytoplasmic region of CD3 T cell receptor chains that when phosphorylated serve as docking sites for downstream signalling molecules.
About this article
Cite this article
Hou, A.J., Chen, L.C. & Chen, Y.Y. Navigating CAR-T cells through the solid-tumour microenvironment. Nat Rev Drug Discov 20, 531–550 (2021). https://doi.org/10.1038/s41573-021-00189-2
Experimental Hematology & Oncology (2022)
Molecular Cancer (2022)
Journal of Experimental & Clinical Cancer Research (2022)
npj Precision Oncology (2021)