Enhanced tumor homing of pathogen-mimicking liposomes driven by R848 stimulation: A new platform for synergistic oncology therapy

Breaking the barriers in effective and safe Toll-like receptor stimulation via nano-immunomodulators for potent cancer immunotherapy

Immunotherapy is an emerging strategy that awakens the intrinsic immune system for cancer treatment. Generally, successful immunotherapy of malignant tumours relies on the effective production of tumour-associated antigens and their lymph node delivery, antigen processing and presentation for T-cell activation, and the dismantling of the immunosuppressive tumour microenvironment. Toll-like receptor (TLR) agonists are potent stimulants in cancer immunotherapy, which can directly activate antigen-presenting cells (APCs) and further induce T cell activation for antitumour immune response and convert immunosuppressive tumour microenvironment to an immunogenic one for cooperative tumour ablation. However, TLR agonists for effective cancer immunotherapy have encountered essential challenges, such as insufficient immune activation and systemic side effects. In recent years, nano-immunomodulators with TLR agonists have been employed for tumour- and/or lymph node-targeted immune activation to improve the antitumour immune response and alleviate their systemic toxicities, providing a promising strategy for enhanced cancer immunotherapy. Herein, we introduce the recent progress in developing various TLR nano-immunomodulators for cancer immunotherapy via APC activation and tumour microenvironment remodelling. Upon elucidating the rational design principles of nano-immunomodulators, we elucidate the advancement of TLR nanoagonists to break the barriers in effective and safe Toll-like receptor stimulation for potent cancer immunotherapy.

Enhancing immunogenicity and release of in situ-generated tumor vesicles for autologous vaccines

In situ vaccination (ISV) strategies offer an innovative approach to cancer immunotherapy by utilizing drug combinations directly at tumor sites to elicit personalized immune responses. Tumor cell-derived extracellular vesicles (TEVs) in ISV have great potential but face challenges such as low release rates and immunosuppressive proteins like programmed death ligand 1 (PD-L1) and CD47. This study develops a nanoparticle-based ISV strategy (Combo-NPs@shGNE) that enhances TEV release and modulates cargo composition. This approach combines Andrographolide, Icariside II, and shRNA targeting UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE), which accumulates in the tumor region, resulting in the regulation of immunosuppressive pathways and the reduction of sialic acid production. Decreasing the level of sialylation on the membrane through necroptosis and inhibition of sialic acid synthesis decreased the loading of PD-L1 and CD47 on vesicles, while increasing the loading of heat shock protein 70 and high mobility group box 1 on vesicles, and induced the release of highly immunogenic TEVs from the cancer cells, with a 56.44 % release, 9.57 times higher than that of blank nanoparticle-treated cells. In vivo studies demonstrate that Combo-NPs@shGNE enhances TEV yield, tumor growth, reduces metastases, and improves survival in an osteosarcoma mouse model. It promotes dendritic cell maturation, increases CD4+ and CD8+ T cell infiltration, and alters the microenvironment by reducing myeloid-derived suppressor cells and enhancing immunostimulatory factors. Additionally, it transitions tumor-associated macrophages from M2 to an M1 phenotype, thereby augmenting tumor immunity. Overall, Combo-NPs@shGNE offers a promising method for transforming tumors into personalized autologous vaccines, potentially advancing cancer treatment strategies.

Characterizing the impact of podophyllotoxin on pulmonary toxicity and gut-lung microbiota interactions in SD rats based on TEC concept

Podophyllotoxin (PPT), an extract from the traditional medicinal plant Dysosma, offers anti-viral and anti-cancer benefits, though its use is limited by toxicity. The mechanisms of PPT's inherent pulmonary toxicity remain elusive. This study leverages the novel "Toxicological Evidence Chain" theory to explore the potential involvement of the "gut-lung axis" in PPT-induced pulmonary toxicity. In this study, we examined injury phenotypes in rats, evaluated pulmonary pathological changes, measured pro-inflammatory factors, and conducted comprehensive analyses of both pulmonary and gut microbiomes and metabolomics. Our findings indicate that exposure to PPT leads to significant pulmonary damage in these animals. The PPT group exhibited significantly elevated levels of total protein, albumin, alkaline phosphatase, and lactate dehydrogenase in bronchoalveolar lavage fluid, accompanied by marked upregulation of interleukin (IL)-18, tumor necrosis factor-alpha, IL-6, and IL-1β expression in lung tissue. Furthermore, 16S rRNA gene sequencing analysis revealed significant increases of Akkermansia, Escherichia-Shigella, and Bacteroides in both intestinal contents and lung tissue of PPT-treated animals, concomitant with notable elevations in short-chain fatty acids (SCFAs) such as isobutyric acid and isovaleric acid, and reductions in acetic acid, propionic acid, and butyric acid. The increased abundance of Akkermansia and Escherichia-Shigella may enhance pulmonary inflammatory factors through effects on intestinal barrier integrity and direct immune stimulation, while elevated Bacteroides may alter SCFA production, exacerbating pulmonary inflammation under PPT treatment, suggesting a potential role in the manifestation of PPT-induced pulmonary toxicity. This study offers new insights into the mechanisms of PPT-induced pulmonary toxicity, highlights the role of the gut-lung axis, and provides avenues for therapeutic intervention.

IMPORTANCE

PPT, derived from the medicinal plant Dysosma, is known for its anti-cancer and anti-viral properties but limited by severe pulmonary toxicity. This study illuminates the gut-lung microbiota axis's role in mediating this toxicity, revealing how specific microbial and metabolic alterations contribute to lung damage. By uncovering these mechanisms, our research opens avenues for interventions that could mitigate PPT's side effects, potentially enhancing its safety and widening its therapeutic use.

Innovative nanoparticle-based approaches for modulating neutrophil extracellular traps in diseases: from mechanisms to therapeutics

Neutrophil extracellular traps (NETs) participate in both host defense and the pathogenesis of various diseases, such as infections, thrombosis, and tumors. While they help capture and eliminate pathogens, NETs' excessive or dysregulated formation can lead to tissue damage and disease progression. Therapeutic strategies targeting NET modulation have shown potential, but challenges remain, particularly in achieving precise drug delivery and maintaining drug stability. Nanoparticle (NP)-based drug delivery systems offer innovative solutions for overcoming the limitations of conventional therapies. This review explores the biological mechanisms of NET formation, their interactions with NPs, and the therapeutic applications of NP-based drug delivery systems for modulating NETs. We discuss how NPs can be designed to either promote or inhibit NET formation and provide a comprehensive analysis of their potential in treating NET-related diseases. Additionally, we address the current challenges and future prospects for NP-based therapies in NET research, aiming to bridge the gap between nanotechnology and NET modulation for the development of novel therapeutic approaches.

Polyphenol-mediated assembly of toll-like receptor 7/8 agonist nanoparticles for effective tumor immunotherapy

Toll-like receptor (TLR) 7/8 agonists have shown significant potential in tumor immunotherapy. However, the limited pharmacokinetic properties and systemic toxicity resulting from off-target effects limits their biomedical applications. We here report the polyphenol-mediated assembly of resiquimod (R848, a TLR7/8 agonist) nanoparticles (RTP NPs) to achieve tumor-selective immunotherapy while avoiding systemic adverse effects. Upon intravenous administration, the prepared RTP NPs are effectively accumulated at tumor sites, which increase their bioavailability and reduce systemic inflammation. RTP NPs can trigger a potent antitumor immune response in a mouse tumor model to inhibit tumor growth. Additionally, after subcutaneous injection at the tail base, RTP NPs efficiently migrate to the lymph nodes, where they elicit immune memory to prevent tumorigenesis. This study underscores the potential application of polyphenol-mediated assembly in developing nanomedicines with reduced toxicity for tumor-specific immunotherapy. STATEMENT OF SIGNIFICANCE: Toll-like receptor agonist (R848) nanoparticles for tumor-selective immunotherapy were synthesized through polyphenol-mediated assembly, a method that simplifies preparation process and minimizes potential side effects. Intravenously administered these nanoparticles effectively extended circulation time, enhanced tumor enrichment, and reduced systemic inflammation, thus augmenting the bioavailability and minimizing the side effects of R848. The nanoparticles significantly inhibited tumor growth by triggering a potent antitumor immune response, including dendritic cell maturation, macrophage polarization, T-cell infiltration, and cytokine secretion. Moreover, after subcutaneous injection at the tail base, they can elicit immune memory to prevent tumorigenesis.

Therapeutic co-assemblies for synergistic NSCLC treatment through dual topoisomerase I and tubulin inhibitors

Camptothecin (CPT) and podophyllotoxin (PPT) function as topoisomerase (TOP) I and tubulin inhibitors, respectively, with potent anticancer effects in a variety of cancers. Despite its promise, the clinical applicability of the combination of CPT and PPT faces challenges, including potential side effect and limited therapeutic efficacy. In this study, we designed co-assembly nanomedicines with the different weight (w/w) ratios of amphiphilic Evans blue conjugated CPT prodrug (EB-ss-CPT) and PPT molecules, denoted as ECT Nano. The co-assembly of EB-ss-CPT and PPT without other excipients has nearly 100% drug loading efficiency and high drug loading content of PPT of up to 74.29 ± 0.90 wt%. Notably, the ECT Nano (1:2) equipped with the ability to inhibit TOP I activity and tubulin polymerization, which provided a highly efficient strategy to improve synergistic efficacy and decrease side toxicity in non-small cell lung cancer mouse model. This work represents a step forward to the development of practical applications for dual TOP I and tubulin inhibitors and especially hopeful to the rational design of combination nanomedicine for therapeutic purposes.

Dual-Functional Nanodroplet for Tumor Vasculature Ultrasound Imaging and Tumor Immunosuppressive Microenvironment Remodeling

Accurately evaluating tumor neoangiogenesis and conducting precise interventions toward an immune-favorable microenvironment are of significant clinical importance. In this study, a novel nanodroplet termed as the nanodroplet-based ultrasound contrast agent and therapeutic (NDsUCA/Tx) is designed for ultrasound imaging and precise interventions of tumor neoangiogenesis. Briefly, the NDsUCA/Tx shell is constructed from an engineered CMs containing the tumor antigen, vascular endothelial growth factor receptor 1 (VEGFR1) extracellular domain 2-3, and CD93 ligand multimerin 2. The core is composed of perfluorohexane and the immune adjuvant R848. After injection, NDsUCA/Tx is found to be enriched in the tumor vasculature with high expression of CD93. When triggered by ultrasound, the perfluorohexane in NDsUCA/Tx underwent acoustic droplet vaporization and generated an enhanced ultrasound signal. Some microbubbles exploded and the resultant debris (with tumor antigen and R848) together with the adsorbed VEGF are taken up by nearby cells. This cleared the local VEGF for vascular normalization, and also served as a vaccine to activate the immune response. Using a syngeneic mouse model, the satisfactory performance of NDsUCA/Tx in tumor vasculature imaging and immune activation is confirmed. Thus, a multifunctional NDsUCA/Tx is successfully developed for molecular imaging of tumor neoangiogenesis and precise remodeling of the tumor microenvironment.

Convergence of nanomedicine and neutrophils for drug delivery

Neutrophils have recently emerged as promising carriers for drug delivery due to their unique properties including rapid response toward inflammation, chemotaxis, and transmigration. When integrated with nanotechnology that has enormous advantages in improving treatment efficacy and reducing side effects, neutrophil-based nano-drug delivery systems have expanded the repertoire of nanoparticles employed in precise therapeutic interventions by either coating nanoparticles with their membranes, loading nanoparticles inside living cells, or engineering chimeric antigen receptor (CAR)-neutrophils. These neutrophil-inspired therapies have shown superior biocompatibility, targeting ability, and therapeutic robustness. In this review, we summarized the benefits of combining neutrophils and nanotechnologies, the design principles and underlying mechanisms, and various applications in disease treatments. The challenges and prospects for neutrophil-based drug delivery systems were also discussed.

Biomimetic nanotechnology for cancer immunotherapy: State of the art and future perspective

Cancer continues to be a significant worldwide cause of mortality. This underscores the urgent need for novel strategies to complement and overcome the limitations of conventional therapies, such as imprecise targeting and drug resistance. Cancer Immunotherapy utilizes the body's immune system to target malignant cells, reducing harm to healthy tissue. Nevertheless, the efficacy of immunotherapy exhibits variation across individuals and has the potential to induce autoimmune responses. Biomimetic nanoparticles (bNPs) have transformative potential in cancer immunotherapy, promising improved accurate targeting, immune system activation, and resistance mechanisms, while also reducing the occurrence of systemic autoimmune side effects. This integration offers opportunities for personalized medicine and better therapeutic outcomes. Despite considerable potential, bNPs face barriers like insufficient targeting, restricted biological stability, and interactions within the tumor microenvironment. The resolution of these concerns is crucial in order to expedite the integration of bNPs from the research setting into clinical therapeutic uses. In addition, optimizing manufacturing processes and reducing bNP-related costs are essential for practical implementation. The present research introduces comprehensive classifications of bNPs as well as recent achievements in their application in cancer immunotherapies, emphasizing the need to address barriers for swift clinical integration.

Neutrophil Extracellular Traps in Tumors and Potential Use of Traditional Herbal Medicine Formulations for Its Regulation

Neutrophil extracellular traps (NETs) are extracellular fibers composed of deoxyribonucleic acid (DNA) and decorated proteins produced by neutrophils. Recently, NETs have been associated with the development of many diseases, including tumors. Herein, we reviewed the correlation between NETs and tumors. In addition, we detailed active compounds from traditional herbal medicine formulations that inhibit NETs, related nanodrug delivery systems, and antibodies that serve as "guiding moieties" to ensure targeted delivery to NETs. Furthermore, we discussed the strategies used by pathogenic microorganisms to evade NETs.

Chemistry and Biology of Podophyllotoxins: An Update

Podophyllotoxin is an aryltetralin lignan lactone derived from different plants of Podophyllum. It consists of five rings with four chiral centers, one trans-lactone and one aryl tetrahydronaphthalene skeleton with multiple modification sites. Moreover, podophyllotoxin and its derivatives showed lots of bioactivities, including anticancer, anti-inflammatory, antiviral, and insecticidal properties. The demand for podophyllotoxin and its derivatives is rising as a result of their high efficacy. As a continuation of our previous review (Chem. Eur. J., 2017, 23, 4467-4526), herein, total synthesis, biotransformation, structural modifications, bioactivities, and structure-activity relationships of podophyllotoxin and its derivatives from 2017 to 2022 are summarized. Meanwhile, a piece of update information on the origin of new podophyllotoxin analogues from plants from 2014 to 2022 was compiled. We hope that this review will provide a reference for future high value-added applications of podophyllotoxin and its analogues in the pharmaceutical and agricultural fields.

Smart Targeted Delivery Systems for Enhancing Antitumor Therapy of Active Ingredients in Traditional Chinese Medicine

As a therapeutic tool inherited for thousands of years, traditional Chinese medicine (TCM) exhibits superiority in tumor therapy. The antitumor active components of TCM not only have multi-target treatment modes but can also synergistically interfere with tumor growth compared to traditional chemotherapeutics. However, most antitumor active components of TCM have the characteristics of poor solubility, high toxicity, and side effects, which are often limited in clinical application. In recent years, delivering the antitumor active components of TCM by nanosystems has been a promising field. The advantages of nano-delivery systems include improved water solubility, targeting efficiency, enhanced stability in vivo, and controlled release drugs, which can achieve higher drug-delivery efficiency and bioavailability. According to the method of drug loading on nanocarriers, nano-delivery systems can be categorized into two types, including physically encapsulated nanoplatforms and chemically coupled drug-delivery platforms. In this review, two nano-delivery approaches are considered, namely physical encapsulation and chemical coupling, both commonly used to deliver antitumor active components of TCM, and we summarized the advantages and limitations of different types of nano-delivery systems. Meanwhile, the clinical applications and potential toxicity of nano-delivery systems and the future development and challenges of these nano-delivery systems are also discussed, aiming to lay the foundation for the development and practical application of nano-delivery systems of TCM in clinical settings.

Targeted co-delivery of resiquimod and a SIRPα variant by liposomes to activate macrophage immune responses for tumor immunotherapy

Tumor-associated macrophages (TAMs) are the major immune cells infiltrating the tumor microenvironment (TME) and typically exhibit an immunosuppressive M2-like phenotype, which facilitates tumor growth and promotes resistance to immunotherapy. Additionally, tumor cells tend to express high levels of CD47, a "don't eat me" signal, that obstructs macrophage phagocytosis. Consequently, re-educating TAMs in combination with CD47 blockage is promising to trigger intense macrophage immune responses against tumors. As a toll-like receptor 7/8 agonist, resiquimod (R848) possesses the capacity to re-educate TAMs from M2 type to M1 type. We found that intratumoral administration of R848 synergistically improved the antitumor immunotherapeutic effect of CV1 protein (a SIRPα variant with high antagonism to CD47). However, the poor bioavailability and potential toxicity of this combo strategy remain a challenge. Here, a TAMs-targeted liposome (named: R-LS/M/CV1) co-delivering R848 and CV1 protein was constructed via decorating mannose on the liposomal surface. R-LS/M/CV1 exhibited high abilities of targeting, re-education and pro-phagocytosis of tumor cells to M2 macrophages in vitro. Intratumoral administration of R-LS/M/CV1 remarkedly eliminated tumor burden in the MC38 tumor model via repolarization of TAMs to M1 type, pro-phagocytosis of TAMs against tumors, and recruitment of tumor-infiltrating T cells. More encouragingly, due to the double targeting to TAMs and tumor cells of mannose and CV1 protein, R-LS/M/CV1 effectively accumulated at the tumor site, thereby not only remarkedly inhibiting tumors, but also exerting no hematological and histopathological toxicity when administered systemically. Our integrated strategy based on re-educating TAMs and CD47 blockade provides a promising approach to trigger macrophage immune responses against tumors for immunotherapy.