Immune Effect Regulated by the Chain Length: Interaction between Immune Cell Surface Receptors and Synthetic Glycopolymers

Synthetic Glycopolymers in Tumor Immunotherapy

Glycopolymers, as an emerging immunomodulatory material, exhibit considerable promise in the field of tumor immunotherapy. Compared to native saccharides, they offer significant advantages, including enhanced immune activity, controllable structure and sequence, elevated stability, and high purity. By mimicking the multivalency of native sugar chains, glycopolymers significantly enhance their interactions with receptors, a phenomenon known as the "glycocluster effect." Glycopolymers are capable of modulating immune cell functions, inhibiting tumor immune evasion, and reconfiguring the tumor microenvironment. This review provides a comprehensive overview of recent advancements in the application of glycopolymers, protein-glycopolymer conjugates, glycopolymer-based micro/nanoparticles, and glycopolymer-engineered cells in tumor immunotherapy. These glycopolymer-based materials enhance antitumor immune responses by specifically interacting with immune cell surface receptors, significantly improving the precision and efficacy of immunotherapy, and providing valuable insights for the development of innovative therapeutic strategies in cancer treatment.

An enzyme-proof glycan glue for extracellular matrix to ameliorate intervertebral disc degeneration

Intervertebral disc degeneration (IDD) remains a global healthcare challenge. Here, by analyzing clinical samples, we discover the loss of milk fat globule-EGF factor 8 (MFG-E8) from the nucleus pulposus (NP) tissue-along with increased enzymatic breakdown of glycosaminoglycans (GAGs)-as an overlooked factor for IDD development. Repairing the degraded NP extracellular matrix (ECM) with a structurally-mimicking glycan glue to enrich MFG-E8 may counter the degeneration. Accordingly, we synthesize a glucomannan octanoate (GMOC) with robust resistance to ECM-cleaving enzymes, which forms assemblies with MFG-E8 to maintain a healthy NP cell phenotype. GMOC injected into the degenerated intervertebral disc enriches MFG-E8 in situ, leading to NP tissue regeneration in a rat and a rabbit model, which represent two clinical scenarios of pre-surgical intervention and post-surgical regeneration of IDD, respectively. In summary, we report enriching MFG-E8 in ECM with a glycan glue as a mechanism to promote NP regeneration for IDD treatment.

Enhanced Whole Tumor Cell-Based Vaccines by a RAFT and Protein Fusion Strategy for Tumor Immunotherapy

Inactivated whole tumor cell-based vaccines (WTVs) are a promising strategy for tumor immunotherapy, but have exhibited limited antitumor effects clinically. Aiming at constructing enhanced WTVs, we developed glycopolymer-engineered WTVs (G-WTVs) using a Halo-Tag protein (HTP) fusion technique and reversible addition-fragmentation chain transfer (RAFT) polymerization. In our study, G-WTVs with varying molecular weights of glycopolymers were constructed. Compared to unmodified tumor cells, all G-WTVs effectively induced the polarization of macrophages toward the M1 phenotype and promoted the secretion of pro-inflammatory cytokines. This enhanced immune response was attributed to the improved interactions between G-WTVs and the macrophages. Among the G-WTVs, the medium molecular weight variant demonstrated the most pronounced enhancement of antitumor immune responses. Notably, the administration of optimized G-WTVs effectively inhibited the growth of B16 melanoma in mice. Our findings provide a new approach to enhance the antitumor efficacy of WTVs via cell membrane glycopolymer engineering, offering a promising strategy for tumor immunotherapy.

Customizable Glycopolymers as Adjuvants for Cancer Immunotherapy: From Branching Degree Optimization to Cell Surface Engineering

Engineering dendritic cell (DC) maturation is paramount for robust T-cell responses and immunological memory, critical for cancer immunotherapy. This work unveils a novel strategy using precisely controlled branching in synthetic glycopolymers to optimize DC activation. Using the distinct copolymerization kinetics of 2-(methacrylamido) glucopyranose (MAG) and diethylene glycol dimethacrylate (DEGDMA) in a RAFT polymerization, unique glycopolymers with varying branching degrees are created. These strategically produced gradient branched glycopolymers with sugar moieties on the outer chain potently promote DC maturation. Strikingly, low-branched glycopolymers demonstrate superior activity, both in pure form and when engineered on tumor cell surfaces. Quartz crystal microbalance and theoretical simulations elucidate the crucial role of branching in modulating glycopolymer-DC receptor interactions. Low-branched gradient glycopolymers have shown a notable advantage and are promising adjuvants in DC-based cancer immunotherapy.

Metal-Free Atom Transfer Radical Polymerization to Prepare Recylable Micro-Adjuvants for Dendritic Cell Vaccine

In the development of dendritic cell (DC) vaccines, the maturation of DCs is a critical stage. Adjuvants play a pivotal role in the maturation of DCs, with a major concern being to ensure both efficacy and safety. This study introduces an innovative approach that combines high efficacy with safety through the synthesis of micro-adjuvants grafted with copolymers of 2-(methacrylamido) glucopyranose (MAG) and methacryloxyethyl trimethyl ammonium chloride (DMC). The utilization of metal-free surface-initiated atom transfer radical polymerization enables the production of safe and recyclable adjuvants. These micrometer-sized adjuvants surpass the optimal size range for cellular endocytosis, enabling the retrieval and reuse of them during the ex vivo maturation process, mitigating potential toxicity concerns associated with the endocytosis of non-metabolized nanoparticles. Additionally, the adjuvants exhibit a "micro-ligand-mediated maturation enhancement" effect for DC maturation. This effect is influenced by the shape of the particle, as evidenced by the distinct promotion effects of rod-like and spherical micro-adjuvants with comparable sizes. Furthermore, the porous structure of the adjuvants enables them to function as cargo-carrying "micro-shuttles", releasing antigens upon binding to DCs to facilitate efficient antigen delivery.

Well-Defined Oligo(azobenzene-graft-mannose): Photostimuli Supramolecular Self-Assembly and Immune Effect Regulation

The immune system can recognize and respond to pathogens of various shapes. Synthetic materials that can change their shape have the potential to be used in vaccines and immune regulation. The ability of supramolecular assemblies to undergo reversible transformations in response to environmental stimuli allows for dynamic changes in their shapes and functionalities. A meticulously designed oligo(azobenzene-graft-mannose) was synthesized using a stepwise iterative method and "click" chemistry. This involved integrating hydrophobic and photoresponsive azobenzene units with hydrophilic and bioactive mannose units. The resulting oligomer, with its precise structure, displayed versatile assembly morphologies and chiralities that were responsive to light. These varying assembly morphologies demonstrated distinct capabilities in terms of inhibiting the proliferation of cancer cells and stimulating the maturation of dendritic cells. These discoveries contribute to the theoretical comprehension and advancement of photoswitchable bioactive materials.

Glycopolymers With On/Off Anchors: Confinement Effect on Regulating Dendritic Cells

Insufficient activation or over-activation of T cells due to the dendritic cells (DCs) state can cause negative effects on immunotherapy, making it crucial for DCs to maintain different states in different treatments. Polysaccharides are one of the most studied substances to promote DCs maturation. However, in many methods, optimizing the spatial dimension of the interaction between polysaccharides and cells is often overlooked. Therefore, in this study, a new strategy from the perspective of spatial dimension is proposed to regulate the efficacy of polysaccharides in promoting DCs maturation. An anchoring molecule (DMA) is introduced to existing glycopolymers for the confinement effect, and the effect can be turned off by oxidation of DMA. Among the prepared on-confined (PMD2 ), off-confined (PMD2 -O), and norm (PM2 ) glycopolymers, PMD2 and PMD2 -O show the best and worst results, respectively, in terms of the amount of binding to DCs and the effect on promoting DCs maturation. This sufficiently shows that the turn-on and off of confinement effect can regulate the maturation of DCs by polysaccharides. Based on the all-atom molecular dynamics (MD) simulation, the mechanism of difference in the confinement effect is explained. This simple method can also be used to regulate other molecule-cell interactions to guide cell behavior.

Engineered Nanoprobes for Immune Activation Monitoring

The activation of the immune system is critical for cancer immunotherapy and treatments of inflammatory diseases. Non-invasive visualization of immunoactivation is designed to monitor the dynamic nature of the immune response and facilitate the assessment of therapeutic outcomes, which, however, remains challenging. Conventional imaging modalities, such as positron emission tomography, computed tomography, etc., were utilized for imaging immune-related biomarkers. To explore the dynamic immune monitoring, probes with signals correlated to biomarkers of immune activation or prognosis are urgently needed. These emerging molecular probes, which turn on the signal only in the presence of the intended biomarker, can improve the detection specificity. These probes with "turn on" signals enable non-invasive, dynamic, and real-time imaging with high sensitivity and efficiency, showing significance for multifunctionality/multimodality imaging. As a result, more and more innovative engineered nanoprobes combined with diverse imaging modalities were developed to assess the activation of the immune system. In this work, we comprehensively review the recent and emerging advances in engineered nanoprobes for monitoring immune activation in cancer or other immune-mediated inflammatory diseases and discuss the potential in predicting the efficacy following treatments. Research on real-time in vivo immunoimaging is still under exploration, and this review can provide guidance and facilitate the development and application of next-generation imaging technologies.

In situ preparation of glyco-micromotors and their bacteria loading/guiding ability

We successfully synthesized glyco-micromotors in situ directed by multifunctional glycopolymers, which were obtained by copolymerizing 2-methacrylamido glucopyranose (MAG) and 2-(diethylamino)ethyl methacrylate (DEAEMA) monomers. The fabricated glyco-micromotors present abilities in loading and guiding bacteria with different individual and group motions.

Glycopolymer Engineering of the Cell Surface Changes the Single Cell Migratory Direction and Inhibits the Collective Migration of Cancer Cells

Cancer cell migration is one of the most important processes in cancer metastasis. Metastasis is the major cause of death from most solid tumors; therefore, suppressing cancer cell migration is an important means of reducing cancer mortality. Cell surface engineering can alter the interactions between cells and their microenvironment, thereby offering an effective method of controlling the migration of the cells. This paper reports that modification of the mouse melanoma (B16) cancer cell surface with glycopolymers affects the migration of the cells. Changes in cell morphology, migratory trajectories, and velocity were investigated by time-lapse cell tracking. The data showed that the migration direction is altered and diffusion slows down for modified B16 cells compared to unmodified B16 cells. When modified and unmodified B16 cells were mixed, wound-healing experiments and particle image velocimetry (PIV) analysis showed that the collective migration of unmodified B16 cells was suppressed because of vortexlike motions induced by the modified cells. The work demonstrates the important role of surface properties/modification in cancer cell migration, thereby providing new insights relative to the treatment of cancer metastasis.

Tailor-made Glycopolymers via Reversible Deactivation Radical Polymerization: Design, Properties and Applications

Investigating the underlying mechanism of biological interactions using glycopolymer is becoming increasingly important owing to their unique recognition properties. The multivalent interactions between lectin and glycopolymer are significantly influenced by...