Photo-regulated control of cytokine signaling via bioinspired, polymer-induced latency

Abstract Cytokine signaling is challenging to study or therapeutically modulate as the effects of these protein are often pleotropic and context-dependent. One mechanism by which cytokines with diverse effects can, however, transmit cell type-specific information is via expression in an inactive, or latent, form in which the protein is sterically shielded by a binding partner that is later displaced or degraded (e.g. TGF-β1 association with GARP or LAP). Inspired by this precision, we hypothesized that photo-reversible chemical modification could impart orthogonal specificity to cytokines not expressed in a latent state, such as IL-2, IL-15, or IL-12. Here, we describe a strategy whereby cytokines are modified with photo-labile polymers that mimic the induction of latency while appended, then de-shield to recover protein activity in response to monochromatic light exposure, thus controlling the magnitude, duration, and location of cytokine signals. Using this strategy, we show that latent IL-2 and IL-15 activity can be photo-modulated as much as 103-fold and that polymer-induced IL-2 latency, alone, can bias affinity away from immunosuppressive CD25 binding. We further show that protein de-repression can be achieved with spatial resolution approaching that of a single immune cell and demonstrate the feasibility of transcutaneous IL-2 photoactivation using engineered tissue phantoms. We find that such modifications also prolong the circulation of IL-12 in vivo, thus obviating the need for frequent, high dosing in therapeutic settings. Future extensions of this approach could enable multicolor, optical reprogramming of cytokine signaling networks and lead to immunotherapies that are more tissue-specific and patient-personalized.</jats:p

Promoting anti-tumor immunity via bispecific T cell engaging cytokine (biteokine) therapy

Abstract Bispecific T cell engager (BiTE) therapy bypasses the need for natural recognition of tumor cells by cytotoxic T cells, inducing potent anti-tumor immunity. Currently, the FDA approved BiTE, Blinatumomab (Blin), provides an alternative to standard chemotherapy in patients with relapsed/refractory or MRD+ Acute Lymphoblastic Leukemia (ALL) and is in clinical trials for other B cell malignancies. Blin targets malignant B cells using the antigen binding domain of an αCD19 antibody linked to the antigen binding domain of a T cell-activating αCD3 antibody. Despite progress with Blin clinically, complete response is 39–69%, and a significant proportion of patients are refractory or relapse. To improve this outcome, we have engineered a nanoparticle-based assembly and screening approach to capitalize on cytokine-enhancement of BiTE activity. We found that IL-12 significantly improves Blin-induced B-ALL cell lysis in vitro and, using nanoparticles capable of displaying ~142 antibodies/particle, we generated 28 unique formulations with varying densities and ratios of antibodies to target CD19, activate CD3, and localize IL-12 in a non-neutralizing fashion. We screened these particles in parallel using a co-culture assay for target cell lysis and T cell expansion by flow cytometry. Through regression modeling of these data, we can select-for and optimize architectures that maximize target cell lysis and T cell proliferation. Our preliminary results indicate that optimally lytic architectures favor high αCD3 to αCD19 ratios and are improved linearly with increasing IL-12. This work seeks to innovate and enhance bispecific T cell engager therapy with a modular platform that can be used broadly in the treatment of cancer and autoimmunity.</jats:p