Matrix Metalloproteinase- and pH-Sensitive Nanoparticle System Enhances Drug Retention and Penetration in Glioblastoma

Glioblastoma (GBM) is a primary malignant brain tumor with limited therapeutic options. One promising approach is local drug delivery, but the efficacy is hindered by limited diffusion and retention. To address this, we synthesized and developed a dual-sensitive nanoparticle (Dual-NP) system, formed between a dendrimer and dextran NPs, bound by a dual-sensitive [matrix metalloproteinase (MMP) and pH] linker designed to disassemble rapidly in the tumor microenvironment. The disassembly prompts the in situ formation of nanogels via a Schiff base reaction, prolonging Dual-NP retention and releasing small doxorubicin (Dox)-conjugated dendrimer NPs over time. The Dual-NPs were able to penetrate deep into 3D spheroid models and detected at the tumor site up to 6 days after a single intratumoral injection in an orthotopic mouse model of GBM. The prolonged presence of Dual-NPs in the tumor tissue resulted in a significant delay in tumor growth and an overall increase in survival compared to untreated or Dox-conjugated dendrimer NPs alone. This Dual-NP system has the potential to deliver a range of therapeutics for efficiently treating GBM and other solid tumors.

Multimodal neuro-nanotechnology: Challenging the existing paradigm in glioblastoma therapy

Integrating multimodal neuro- and nanotechnology-enabled precision immunotherapies with extant systemic immunotherapies may finally provide a significant breakthrough for combatting glioblastoma (GBM). The potency of this approach lies in its ability to train the immune system to efficiently identify and eradicate cancer cells, thereby creating anti-tumor immune memory while minimizing multi-mechanistic immune suppression. A critical aspect of these therapies is the controlled, spatiotemporal delivery of structurally defined nanotherapeutics into the GBM tumor microenvironment (TME). Architectures such as spherical nucleic acids or poly(beta-amino ester)/dendrimer-based nanoparticles have shown promising results in preclinical models due to their multivalency and abilities to activate antigen-presenting cells and prime antigen-specific T cells. These nanostructures also permit systematic variation to optimize their distribution, TME accumulation, cellular uptake, and overall immunostimulatory effects. Delving deeper into the relationships between nanotherapeutic structures and their performance will accelerate nano-drug development and pave the way for the rapid clinical translation of advanced nanomedicines. In addition, the efficacy of nanotechnology-based immunotherapies may be enhanced when integrated with emerging precision surgical techniques, such as laser interstitial thermal therapy, and when combined with systemic immunotherapies, particularly inhibitors of immune-mediated checkpoints and immunosuppressive adenosine signaling. In this perspective, we highlight the potential of emerging treatment modalities, combining advances in biomedical engineering and neurotechnology development with existing immunotherapies to overcome treatment resistance and transform the management of GBM. We conclude with a call to action for researchers to leverage these technologies and accelerate their translation into the clinic.

cGAS-STING pathway agonists are promising vaccine adjuvants

Adjuvants are of critical value in vaccine development as they act on enhancing immunogenicity of antigen and inducing long-lasting immunity. However, there are only a few adjuvants that have been approved for clinical use, which highlights the need for exploring and developing new adjuvants to meet the growing demand for vaccination. Recently, emerging evidence demonstrates that the cGAS-STING pathway orchestrates innate and adaptive immunity by generating type I interferon responses. Many cGAS-STING pathway agonists have been developed and tested in preclinical research for the treatment of cancer or infectious diseases with promising results. As adjuvants, cGAS-STING agonists have demonstrated their potential to activate robust defense immunity in various diseases, including COVID-19 infection. This review summarized the current developments in the field of cGAS-STING agonists with a special focus on the latest applications of cGAS-STING agonists as adjuvants in vaccination. Potential challenges were also discussed in the hope of sparking future research interests to further the development of cGAS-STING as vaccine adjuvants.

Overcoming challenges in the delivery of STING agonists for cancer immunotherapy: A comprehensive review of strategies and future perspectives

STING (Stimulator of Interferon Genes) agonists have emerged as promising agents in the field of cancer immunotherapy, owing to their excellent capacity to activate the innate immune response and combat tumor-induced immunosuppression. This review provides a comprehensive exploration of the strategies employed to develop effective formulations for STING agonists, with particular emphasis on versatile nano-delivery systems. The recent advancements in delivery systems based on lipids, natural/synthetic polymers, and proteins for STING agonists are summarized. The preparation methodologies of nanoprecipitation, self-assembly, and hydrogel, along with their advantages and disadvantages, are also discussed. Furthermore, the challenges and opportunities in developing next-generation STING agonist delivery systems are elaborated. This review aims to serve as a reference for researchers in designing novel and effective STING agonist delivery systems for cancer immunotherapy.

Investigation of the enhanced antitumour potency of STING agonist after conjugation to polymer nanoparticles

Intravenously administered cyclic dinucleotides and other STING agonists are hampered by low cellular uptake and poor circulatory half-life. Here we report the covalent conjugation of cyclic dinucleotides to poly(β-amino ester) nanoparticles through a cathepsin-sensitive linker. This is shown to increase stability and loading, thereby expanding the therapeutic window in multiple syngeneic tumour models, enabling the study of how the long-term fate of the nanoparticles affects the immune response. In a melanoma mouse model, primary tumour clearance depends on the STING signalling by host cells-rather than cancer cells-and immune memory depends on the spleen. The cancer cells act as a depot for the nanoparticles, releasing them over time to activate nearby immune cells to control tumour growth. Collectively, this work highlights the importance of nanoparticle structure and nano-biointeractions in controlling immunotherapy efficacy.

Localized Nanoparticle-Mediated Delivery of miR-29b Normalizes the Dysregulation of Bone Homeostasis Caused by Osteosarcoma whilst Simultaneously Inhibiting Tumor Growth

Patients diagnosed with osteosarcoma undergo extensive surgical intervention and chemotherapy resulting in dismal prognosis and compromised quality of life owing to poor bone regeneration, which is further compromised with chemotherapy delivery. This study aims to investigate if localized delivery of miR-29b-which is shown to promote bone formation by inducing osteoblast differentiation and also to suppress prostate and cervical tumor growth-can suppress osteosarcoma tumors whilst simultaneously normalizing the dysregulation of bone homeostasis caused by osteosarcoma. Thus, the therapeutic potential of microRNA (miR)-29b is studied to promote bone remodeling in an orthotopic model of osteosarcoma (rather than in bone defect models using healthy mice), and in the context of chemotherapy, that is clinically relevant. A formulation of miR-29b:nanoparticles are developed that are delivered via a hyaluronic-based hydrogel to enable local and sustained release of the therapy and to study the potential of attenuating tumor growth whilst normalizing bone homeostasis. It is found that when miR-29b is delivered along with systemic chemotherapy, compared to chemotherapy alone, the therapy provided a significant decrease in tumor burden, an increase in mouse survival, and a significant decrease in osteolysis thereby normalizing the dysregulation of bone lysis activity caused by the tumor.

Overcoming STING Agonists Barriers: Peptide, Protein, Biomembrane-based Biocompatible Delivery Strategies

After the development for more ten years, stimulator of interferon genes (STING), a representative of pattern recognition receptors (PRRs), is now entering the stage of widespread applications. Along with evolution of STING agonists of cyclic dinucleotides (CDNs) and non-nucleotide molecules, the stability of agonists has been improved. However, their poor performance in clinical trials triggers urgent demands for highly effective delivery strategies to further improve the cellular permeability, tissue targetability and retention. In this review, we summarized the recent progress of STING agonists applications and delivery strategies with a focus on the biocompatible platforms of peptide, protein and biomembrane, providing a novel vision for STING field and future direction.

Spherical Nucleic Acid Vaccine Structure Markedly Influences Adaptive Immune Responses of Clinically Utilized Prostate Cancer Targets

Cancer vaccines, which activate the immune system against a target antigen, are attractive for prostate cancer, where multiple upregulated protein targets are identified. However, many clinical trials implementing peptides targeting these proteins have yielded suboptimal results. Using spherical nucleic acids (SNAs), we explore how precise architectural control of vaccine components can activate a robust antigen-specific immune response in comparison to clinical formulations of the same targets. The SNA vaccines incorporate peptides for human prostate-specific membrane antigen (PSMA) or T-cell receptor γ alternate reading frame protein (TARP) into an optimized architecture, resulting in high rates of immune activation and cytolytic ability in humanized mice and human peripheral blood mononuclear cells (hPBMCs). Specifically, administered SNAs elevate the production and secretion of cytokines and increase polyfunctional cytotoxic T cells and effector memory. Importantly, T cells raised from immunized mice potently kill targets, including clinically relevant cells expressing the whole PSMA protein. Treatment of hPBMCs increases costimulatory markers and cytolytically active T cells. This work demonstrates the importance of vaccine structure and its ability to reformulate and elevate clinical targets. Moreover, it encourages the field to reinvestigate ineffective peptide targets and repackage them into optimally structured vaccines to harness antigen potency and enhance clinical outcomes.