Precision Tumor Recognition by T Cells With Combinatorial Antigen-Sensing Circuits

Roybal, Kole T.; Rupp, Levi J.; Morsut, Leonardo; Walker, Whitney J.; McNally, Krista; Park, Jason S.; Lim, Wendell A.

doi:10.1016/j.cell.2016.01.011

Cited by 803 publications

(735 citation statements)

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“…CAR-based (38,39) and synNotch/CAR AND gates (40) were designed to increase the safety of adoptive T-cells therapy by targeting only cells that display two cancer-specific surface markers. Nevertheless, it may also come at the risk of tumor cells escaping the treatment due to antigens heterogeneity and immunoediting.…”

Section: Discussionmentioning

confidence: 99%

Cellular heterogeneity mediates inherent sensitivity–specificity tradeoff in cancer targeting by synthetic circuits

Morel

Shtrahman

Rotter

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Synthetic gene circuits are emerging as a versatile means to target cancer with enhanced specificity by combinatorial integration of multiple expression markers. Such circuits must also be tuned to be highly sensitive because escape of even a few cells might be detrimental. However, the error rates of decision-making circuits in light of cellular variability in gene expression have so far remained unexplored. Here, we measure the single-cell response function of a tunable logic AND gate acting on two promoters in heterogeneous cell populations. Our analysis reveals an inherent tradeoff between specificity and sensitivity that is controlled by the AND gate amplification gain and activation threshold. We implement a tumor-mimicking cellculture model of cancer cells emerging in a background of normal ones, and show that molecular parameters of the synthetic circuits control specificity and sensitivity in a killing assay. This suggests that, beyond the inherent tradeoff, synthetic circuits operating in a heterogeneous environment could be optimized to efficiently target malignant state with minimal loss of specificity.synthetic gene circuits | cellular heterogeneity | cancer gene therapy | cell-state targeting | mammalian synthetic biology T he design of gene circuits capable of precisely targeting cancer cells is a major challenge in synthetic biology (1-3), in light of the prospects of using engineered viruses for cancer gene therapy (4), or designing T cells expressing chimeric antigen receptors (CAR-T) (5). Ideally, targeting circuits must be highly sensitive to eradicate all cancer cells, and sufficiently specific to protect surrounding tissues. Gene expression markers that are hyperactive in cancer but not in healthy cells are natural candidates for cancer gene therapy (6). However, a single marker does not suffice because it might be moderately active in normal cells, which would result in incorrect identification. Combining multiple markers improves specificity because a weakly active one will buffer the others by thresholding (7,8), as in Boolean logic circuits converting graded inputs into digital-like output (9-14). The response function of such circuits--input/output activation threshold, amplitude, and sharpness--can be tuned by DNA specificity, promoter design, or protein-protein affinity (15, 16).We previously reported a dual-promoter integrator (DPI) as a logic AND gate to combine the activity of two cancer-specific promoters, and express a reporter or killer gene only when both promoters are decidedly active (17). Subsequently, others used a multiinput logic circuit based on microRNAs to target cancer (18). This Boolean approach provides reliable results on average, but ignores the heterogeneity of cell states. Input values may span a continuum due to expression noise (19,20) and cancer heterogeneity (21). Furthermore, so-called synthetic circuits are not truly digital all-or-none, but rather analog systems that produce continuous signals using transcription factors, expression regulators, and machi...

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Section: Discussionmentioning

confidence: 99%

Cellular heterogeneity mediates inherent sensitivity–specificity tradeoff in cancer targeting by synthetic circuits

Morel

Shtrahman

Rotter

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…In these split constructs, antigen-binding and intracellular signaling components are separated without a dimerization agent, and then assembled together only in the presence of a heterodimerization-promoting small molecule, thus allowing one to precisely control the timing, location, and dosage of T cell activity for controlling potential toxicity [196]. Furthermore, several new designs of the CAR technology based on a synthetic Notch receptor system have been reported to enable T cell activation through recognition of combinational antigens, and to allow engineering of T cells with customized therapeutic response programs [197][198][199]. These studies illustrate the potential of combining cellular engineering with synthetic biology tools to produce safer therapeutic CAR-T cells for cancer immunotherapy.…”

Section: Car-engineered T Cell Immunotherapymentioning

confidence: 99%

“…Thus, while cancer vaccines using tissue-specific antigens or CT antigens such as MAGE-A3 are safe, but not potent enough to eradicate cancer, clinical studies using affinity-enhanced TCRs show the increased ability to recognize target tumor cells, but they also increase the risks of self-destruction of normal tissues or cross-reactivity against unanticipated targets expressed in essential normal tissues. For these reasons, it is better to include an inducible safety cassette or a regulatory switch in these TCR constructs, as demonstrated in CAR-based constructs [196,197,208].…”

Section: Tcr-engineered T Cell Immunotherapymentioning

confidence: 99%

Immune targets and neoantigens for cancer immunotherapy and precision medicine

2016

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“…41 Other elegantly designed logic-gate T cells have also been reported and some of them also require dual antigen recognition for CAR-T activation. 36,37 Our mCAR method offers one more strategy to create conditionally active CARs for enhancing tumor-specificity of CAR-T cells with less structural complexity.…”

mentioning

confidence: 99%

“…[36][37][38][39][40][41] One elegant strategy exploits dual targeting with two CARs to achieve selective recognition of tumor, but not normal cells. Sadelain and co-workers 38 demonstrated that T cells expressing two CARs targeting two different antigens could operate as logic gates to control full T cell activation.…”

mentioning

confidence: 99%