Bypassing evolutionary dead ends and switching the rate-limiting step of a human immunotherapeutic enzyme.

The Trp metabolite kynurenine (KYN) accumulates in numerous solid tumours and mediates potent immunosuppression. Bacterial kynureninases (KYNases), which preferentially degrade kynurenine, can relieve immunosuppression in multiple cancer models, but immunogenicity concerns preclude their clinical use, while the human enzyme (HsKYNase) has very low activity for kynurenine and shows no therapeutic effect. Using fitness selections, we evolved a HsKYNase variant with 27-fold higher activity, beyond which exploration of >30 evolutionary trajectories involving the interrogation of >10 variants led to no further improvements.

Small molecule-inducible gene regulatory systems in mammalian cells: progress and design principles.

Small molecule-inducible gene circuits are some of the most important tools in biology because they provide a convenient way to exert precise regulation of biological systems. These systems typically are designed to govern gene activation, repression, or disruption at multiple levels, such as through genome modification, transcription, translation, or post-translational regulation of protein activity. Due to their importance, many new systems have been created in the past few years to address different needs or afford orthogonality.

Ganglioside-Functionalized Nanoparticles for Chimeric Antigen Receptor T-Cell Activation at the Immunological Synapse.

Chimeric Antigen Receptor (CAR) T cell therapy has proven to be an effective strategy against hematological malignancies but persistence and activity against solid tumors must be further improved. One emerging strategy for enhancing efficacy is based on directing CAR T cells to antigen presenting cells (APCs). Activation of CAR T cells at the immunological synapse (IS) formed between APC and T cell is thought to promote strong, persistent antigen-specific T cell-mediated immune responses but requires integration of CAR ligands into the APC/T-cell interface.