Next generation CAR T cells for AML therapy

Background:
We have developed chimeric antigen receptors (CARs) specific for the AML antigens CD123, CD33 and CLL1 derived from single domain binders and tested their antitumour efficacy when expressed on CAR T cells (ref 1). However, the tumour microenvironment in AML can be highly immunosuppressive to T cells, with expression of multiple co-inhibitory receptors (ref 2). The immune context in AML is highly relevant to application of successful immune therapies in AML (ref 3). Thus, manipulation of this immune context through advanced CAR T cell engineering may improve the anti-tumour efficacy of CAR T cell therapy.

Aims/Objectives:
To develop next generation CAR T cells for AML therapy:
1. To develop lenti or retroviral constructs to express single or multiple AML CARs as well as human cytokines e.g. IL12, IL 15, IL 21, as well as other signalling moieties which may confer resistance to an inhibitory immune enivironment e.g. PD1-CD28 switch receptors.
2. To test CAR T cells bearing AML CARs alone against next generation AML CAR T cells transduced with the constructs generated in 1. and compare anti-tumour responses in vitro.

Methods and Timeline:
0-12 Months of the project:
1. CAR T cells will be generated through lenti or retroviral transduction of T cells.
2. Antigen-specific responses (cytotoxicity, proliferation, cytokine production) of CAR T cells bearing AML CARs alone vs next generation AML CAR T cells transduced with the constructs generated in 1. will be compared in vitro.
12-36 Months of the project:
3. Anti-tumour efficacy of CAR T cells bearing AML CARs alone vs next generation AML CAR T cells transduced with the constructs generated in 1. will be compared in vivo in an immunodeficient (NSG) model of MOLM14ffluc AML.

References:
1.  Hazelton et al., Nanobody Based Tri-Specific Chimeric Antigen Receptor to Treat Acute Myeloid Leukaemia. Blood 2020; 136 (Supplement 1): 10–11. doi: https://doi.org/10.1182/blood-2020-141214
2.  Isidori A, et al., The role of the immunosuppressive microenvironment in acute myeloid leukemia development and treatment. Expert Rev Hematol. 2014 Dec;7(6):807-18. doi: 10.1586/17474086.2014.958464. Epub 2014 Sep 16.
3.  Vadakekolathu et al., Immune landscapes predict chemotherapy resistance and immunotherapy response in acute myeloid leukemia Science Translational Medicine  03 Jun 2020: Vol. 12, Issue 546, eaaz0463 DOI: 10.1126/scitranslmed.aaz0463.