Ultrasound improved immune adjuvant delivery to induce DC maturation and T cell activation

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.

Ultrasound-triggered drug-loaded nanobubbles for enhanced T cell recruitment in cancer chemoimmunotherapy

Chemotherapy combined with immunotherapy is a highly promising approach for treating tumors. However, chemotherapeutic drugs often fail to accumulate effectively at the tumor site after systemic administration and they lack sufficient immunogenicity to activate adaptive immunity, making an effective T-cell immune response within the tumor microenvironment difficult to achieve. Here, this work developed drug-loaded nanobubbles (DTX-R837@NBs) that encapsulate the chemotherapy drug docetaxel and the immune adjuvant R837 via a thin-film hydration method. Ultrasound-targeted nanobubble destruction promoted drug accumulation within tumor tissues and damaged tumor cells through the cavitation effect, inducing immunogenic cell death and releasing damage-associated molecular patterns to augment dendritic cell maturation. Notably, DTX-R837@NBs exhibited excellent contrast-enhanced ultrasound imaging capabilities, enabling the seamless integration of diagnosis and treatment. In combination with immune checkpoint blockade targeting programmed cell death protein 1 (PD-1), the generated immunological responses attacked residual tumor cells and ameliorated the immunosuppressive tumor microenvironment, inhibiting distant tumor growth and metastasis. Moreover, this strategy exhibited robust immune memory effects, effectively protecting the host and preventing tumor recurrence upon rechallenge. Overall, ultrasound-mediated DTX-R837@NBs combined with anti-PD-1 immune checkpoint blockade therapy exhibits robust antitumor efficiency, represent a promising strategy for overcoming immunotherapy resistance in cold tumors, and warrant further investigation for clinical translation.

Ultrasound meets nanomedicine: towards disease treatment and medical imaging

As a kind of mechanical wave, ultrasound has been widely employed in the biomedical field due to its superiors of deep tissue penetration, non-destructiveness and non-toxicity. In this review, we highlight current progress and prospects in using ultrasound as a powerful tool for disease treatment and medical imaging, including (1) ultrasound as energy input for driving nano/micromotor in drug delivery, this part first introduces the synthesis and motion behavior of nano/micromotors, then reviews the small molecular and macromolecular compounds that the nano/micromotors are delivering; (2) sonosensitive nanomaterials for disease therapy, the sonodynamic, sonopiezoelectric, sonothermal, and sonomechanical therapy will all be covered; (3) ultrasound as a non-invasive technique for nano/micromotor tracking or medical imaging; (4) the sonoporation of nano/microbubble. Future challenges in using ultrasound for disease treatment or medical imaging will also be described in the conclusion part.

Precise modulation of cell activity using sono-responsive nano-transducers

Ultrasound, as a form of mechanical energy, possesses a distinctive ability to deeply penetrate tissues, allowing for non-invasive manipulation of cellular activities. Utilizing nanomaterials in conjunction with ultrasound has enabled simple, efficient, spatiotemporally controllable, and minimally invasive regulation of cellular activities with ultrasound-generated electric, optical, acoustic, or chemical stimuli at the localized nanomaterials interface. This technology allows for precise and localized regulation of cellular activities, which is essential for studying and understanding complex biological processes, and also provides new opportunities for research, diagnostics, and therapeutics in the fields of biology and medicine. In this article, we review the state-of-the-art and ongoing developments in nanomaterials-enabled ultrasound cellular modulation, highlighting potential applications and advancements achieved through the integration of sono-responsive nanomaterials with ultrasound.

Exploring the Potential of Nanocarriers for Cancer Immunotherapy: Insights into Mechanism, Nanocarriers, and Regulatory Perspectives

Immunotherapy is a cutting-edge approach that leverages sophisticated technology to target tumor-specific antibodies and modulate the immune system to eradicate cancer and enhance patients' quality of life. Bioinformatics and genetic science advancements have made it possible to diagnose and treat cancer patients using immunotherapy technology. However, current immunotherapies against cancer have limited clinical benefits due to cancer-associated antigens, which often fail to interact with immune cells and exhibit insufficient therapeutic targeting with unintended side effects. To surmount this challenge, nanoparticle systems have emerged as a potential strategy for transporting immunotherapeutic agents to cancer cells and activating immune cells to combat tumors. Consequently, this process potentially generates an antigen-specific T cells response that effectively suppresses cancer growth. Furthermore, nanoplatforms have high specificity, efficacy, diagnostic potential, and imaging capabilities, making them promising tools for cancer treatment. However, this informative paper delves into the various available immunotherapies, including CAR T cells therapy and immune checkpoint blockade, cytokines, cancer vaccines, and monoclonal antibodies. Furthermore, the paper delves into the concept of theragnostic nanotechnology, which integrates therapy and diagnostics for a more personalized treatment approach for cancer therapy. Additionally, the paper covers the potential benefits of different nanocarrier systems, including marketed immunotherapy products, clinical trials, regulatory considerations, and future prospects for cancer immunotherapy.

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.

The advance of ultrasound-enabled diagnostics and therapeutics

Point-of-care ultrasound demonstrates significant potential in biomedical research due to its noninvasive, real-time visualization, cost-effectiveness, and other biological benefits. Ultrasound irradiation can precisely control the mechanical and physicochemical effects on pathogenic lesions, enabling real-time visualization, tunable tissue penetration depth, and therapeutic applications. This review summarizes recent advancements in ultrasound-enabled diagnostics and therapeutics, focusing on mechanochemical effects that can be directly integrated into biomedical applications. Additionally, the structure-functionality relationships of sonotheranostic nanoplatforms are systematically discussed, providing insights into the underlying biological effects. Finally, the limitations of current ultrasonic medicine are discussed, along with potential expansions to facilitate patient-centered translations.

Ultrasound Molecular Imaging Enhances High-Intensity Focused Ultrasound Ablation on Liver Cancer With B7-H3-Targeted Microbubbles

BACKGROUND

High-intensity focused ultrasound (HIFU) is a promising minimally invasive treatment for liver cancer; however, its efficacy is often limited by the attenuation of ultrasonic energy. This study investigates the effectiveness of B7-H3-targeted microbubbles (T-MBs) in enhancing HIFU ablation of liver cancer and explores their potential for clinical translation.

METHODS

T-MBs and isotype control microbubbles (I-MBs) were synthesized through the conjugation of biotinylated anti-B7-H3 antibody and isotype control antibody to the microbubble surface, respectively. Contrast-enhanced ultrasound imaging was performed to compare the accumulation of T-MBs and I-MBs in liver cancer at various time points. The efficacy of T-MBs in enhancing HIFU treatment was evaluated by measuring the immediate tumor ablation rate and long-term tumor growth suppression. Additionally, the induced antitumor immune response was assessed through cytokine quantification in serum and tumor tissue, along with immunofluorescence staining conducted on days 1, 3, and 7 post-treatment.

RESULTS

T-MBs demonstrated superior liver cancer-specific accumulation, characterized by higher concentrations and prolonged retention compared to I-MBs. The combination of T-MBs with HIFU resulted in significantly enhanced tumor ablation rates and superior tumor growth suppression. Post-treatment analysis revealed a gradual uptick in cytokine levels within the tumor microenvironment, along with progressive infiltration of antitumor immune cells.

CONCLUSION

T-MBs effectively enhance the therapeutic efficacy of HIFU for liver cancer treatment while simultaneously promoting an antitumor immune response. These findings provide a strong experimental foundation for the clinical translation of ultrasound molecular imaging combined with HIFU as a novel approach for tumor therapy.

Advances in and prospects of immunotherapy for prostate cancer

Immunotherapy has shown promising therapeutic effects in hematological malignancies and certain solid tumors and has emerged as a critical and highly potential treatment modality for cancer. However, prostate cancer falls under the category of immune-resistant cold tumors, for which immunotherapy exhibits limited efficacy in patients with solid tumors. Thus, it is important to gain a deeper understanding of the tumor microenvironment in prostate cancer to facilitate immune system activation and overcome immune suppression to advance immunotherapy for prostate cancer. In this review, we discuss the immunosuppressive microenvironment of prostate cancer, which is characterized by the presence of few tumor-infiltrating lymphocytes, abundant immunosuppressive cells, low immunogenicity, and a noninflammatory phenotype, which significantly influences the efficacy of immunotherapy for prostate cancer. Immunotherapy is mainly achieved by activating the host immune system and overcoming immunosuppression. In this regard, we summarize the therapeutic advances in immune checkpoint blockade, immunogenic cell death, reversal of the immunosuppressive tumor microenvironment, tumor vaccines, immune adjuvants, chimeric antigen receptor T-cell therapy, and overcoming penetration barriers in prostate cancer, with the aim of providing novel research insights and approaches to enhance the effectiveness of immunotherapy for prostate cancer.

Fe3O4@R837 Nanoplatform Enhances Chemical Dynamic Therapy and Immunotherapy: Integrated Transcriptomic Analysis Reveals Key Genes in Breast Cancer Prognosis

Breast cancer represents a substantial contributor to mortality rates among women with cancer. Chemical dynamic therapy is a promising anticancer strategy that utilizes the Fenton reaction to transform naturally occurring hydrogen peroxide (H2O2) into hydroxyl radicals (•OH). Additionally, cancer immunotherapy using immune drugs, such as imiquimod (R837), has shown promise in activating T cells to kill tumor cells. In this study, we proposed a Fe3O4@R837 smart nanoplatform that can trigger the Fenton reaction and induce immune responses in breast cancer treatment. Furthermore, we performed transcriptome sequencing on breast cancer samples and used the R package (limma) to analyze differential expression profiles and select differentially expressed genes (DEGs). We obtained clinical information and RNA expression matrix data from The Cancer Genome Atlas database to perform survival analysis and identify prognostic-related genes (PRGs) and molecular subtypes with distinct prognoses. We used the TIMER 2.0 web and other methods to determine the tumor immune microenvironment and immune status of different prognostic subtypes. We identified DPGs by taking the intersection of DEGs and PRGs and performed functional analyses, including gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, to elucidate potential mechanisms. Subsequently, we constructed a protein-protein interaction network using the STRING database to visualize the interactions between the DPGs. We screened hub genes from the DPGs using the Cytoscape plugin and identified six hub genes: CD3E, GZMK, CD27, SH2D1A, ZAP70, and TIGIT. Our results indicate that these six key genes regulate immune cell recruitment to increase T-cell cytotoxicity and kill tumors. Targeting these key genes can enhance immunotherapy and improve the breast cancer prognosis.

The emergence of cancer sono-immunotherapy

Owing to its remarkable ease of use, ultrasound has recently been explored for stimulating or amplifying immune responses during cancer therapy, termed 'sono-immunotherapy'. Ultrasound can cause immunogenic cell death in cancer cells via thermal and nonthermal effects to regulate the tumor microenvironment, thereby priming anticancer immunity; by integrating well-designed biomaterials, novel sono-immunotherapy approaches with augmented efficacy can also be developed. Here, we review the advances in sono-immunotherapy for cancer treatment and summarize existing limitations along with potential trends. We offer emerging insights into this realm, which might prompt breakthroughs and expand its potential applications to other diseases.

Heating tumors with tumor cell-derived nanoparticles to enhance chemoimmunotherapy for colorectal cancer

Aim: To investigate the mechanism of doxorubicin (DOX)-induced immunogenic cell death (ICD) and to improve immunotherapy efficacy. Materials & methods: In this study, hybrid vesicles containing DOX (HV-DOX) were prepared by thin-film hydration with extrusion, and the formulated nanoparticles were characterized physically. Furthermore, in vitro experiments and animal models were used to investigate the efficacy and new mechanisms of chemotherapy combined with immunotherapy. Results: DOX improved tumor immunogenicity by alkalinizing lysosomes, inhibiting tumor cell autophagy and inducing ICD. HVs could activate dendritic cell maturation, synergistically enhancing chemotherapeutic immunity. Conclusion: The mechanism of DOX-induced ICD was explored, and antitumor immunity was synergistically activated by HV-DOX to improve chemotherapeutic drug loading and provide relevant antigenic information.

Ultrasound-mediated PLGA-PEI Nanobubbles Carrying STAT6 SiRNA Enhances NSCLC Treatment via Repolarizing Tumor-associated Macrophages from M2 to M1 Phenotypes

BACKGROUND

Tumor-associated macrophages (TAMs) are crucial for non-small cell lung cancer (NSCLC) development.

OBJECTIVE

In this study, polylactic acid-co-glycolic acid (PLGA)-polyethylenimine (PEI) nanobubbles (NBs) carrying STAT6 siRNA were prepared and combined with ultrasound-mediated nanobubbles destruction (UMND) to silence the STAT6 gene, ultimately repolarizing TAMs from the M2 to the M1 phenotype, treating NSCLC in vitro.

METHODS

PLGA-PEI NBs-siRNA were prepared and characterised, and their respective ultrasound imaging, biological stabilities and cytotoxicities were detected. Transfection efficiency was evaluated by fluorescence microscopy and flow cytometry. Repolarization of THP-1-derived M2-like macrophages was determined by qPCR and flow cytometry. NSCLC cells (A549) were co-cultured with transfected M2-like macrophages or their associated conditioned medium (CM). Western blotting was used to detect STAT6 gene silencing in M2-like macrophages and markers of epithelial and mesenchymal in A549 cells. The proliferation of A549 cells was detected using CCK-8 and cell colony formation assays. Transwell assays were used to detect the migration and invasion of A549 cells.

RESULTS

PLGA-PEI NBs-siRNA had an average size of 223.13 ± 0.92 nm and a zeta potential of about -5.59 ± 0.97 mV. PLGA-PEI NBs showed excellent ultrasonic imaging capability in addition to biological stability to protect siRNA from degradation. UMND enhanced PLGA-PEI NBs-STAT6 siRNA transfection in M2-like macrophages, which made M2-like macrophages repolarize to M1-like macrophages and prevented proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) in A549 cells.

CONCLUSION

UMND enhanced PLGA-PEI NBs-STAT6 siRNA to repolarize TAMs from the M2 to the M1 phenotype, thus treating NSCLC. These findings provide a promising therapeutic approach for enhancing NSCLC immunotherapy.

Microbubbles-assisted ultrasonication to promote tumor accumulation of therapeutics and modulation of tumor microenvironment for enhanced cancer treatments

Abnormal tumor vasculature is reported to severely hinder the therapeutic potency of diverse cancer therapeutics by restricting their intratumoral accumulation and/or causing therapeutic resistance. Herein, a microbubble-assisted ultrasonication technology (MAUT) of systemic administration of octafluoropropane-filled microbubbles together with tumor localized ultrasound (US) exposure is developed to generally promote intratumoral accumulation efficacy of three kinds of anti-tumor drugs with varying sizes through the cavitation effect-induced disruption of tumor blood vessels. MAUT was further shown to enable selective tumor hypoxia attenuation by filling microbubbles with high-purity oxygen and thus reducing the production of immunosuppressive lactic acids by suppressing glycolysis in cancer cells. Resultantly, MAUT markedly enhanced the therapeutic outcome of systemically administered anti-programmed death-1 (anti-PD-1) and chemotherapeutic doxorubicin (DOX) with and without using nanoscale liposomes as delivery vehicles. This work highlights that MAUT is a biocompatible yet versatile strategy to effectively reinforce the therapeutic potency of a broad range of cancer therapeutics, promising for future clinical usage.

In Situ Tumor Vaccine for Lymph Nodes Delivery and Cancer Therapy Based on Small Size Nanoadjuvant

Tumor vaccine is a promising cancer treatment modality, however, the convenient antigens loading in vivo and efficient delivery of vaccines to lymph nodes (LNs) still remain a formidable challenge. Herein, an in situ nanovaccine strategy targeting LNs to induce powerful antitumor immune responses by converting the primary tumor into whole-cell antigens and then delivering these antigens and nanoadjuvants simultaneously to LNs is proposed. The in situ nanovaccine is based on a hydrogel system, which loaded with doxorubicin (DOX) and nanoadjuvant CpG-P-ss-M. The gel system exhibits ROS-responsive release of DOX and CpG-P-ss-M, generating abundant in situ storage of whole-cell tumor antigens. CpG-P-ss-M adsorbs tumor antigens through the positive surface charge and achieves charge reversal, forming small-sized and negatively charged tumor vaccines in situ, which are then primed to LNs. Eventually, the tumor vaccine promotes antigens uptake by dendritic cells (DCs), maturation of DCs, and proliferation of T cells. Moreover, the vaccine combined with anti-CTLA4 antibody and losartan inhibits tumor growth by 50%, significantly increasing the percentage of splenic cytotoxic T cells (CTLs), and generating tumor-specific immune responses. Overall, the treatment effectively inhibits primary tumor growth and induces tumor-specific immune response. This study provides a scalable strategy for in situ tumor vaccination.

Advancements in pH-responsive nanocarriers: enhancing drug delivery for tumor therapy

INTRODUCTION

Tumors pose a significant global economic and health burden, with conventional cancer treatments lacking tumor specificity, leading to limited efficiency and undesirable side effects. Targeted tumor therapy is imminent. Tumor cells produce lactate and hydrogen ions (H+) by Warburg effect, forming an acidic tumor microenvironment (TME), which can be employed to design targeted tumor therapy. Recently, progress in nanotechnology has led to the development of pH-responsive nanocarriers, which have gathered significant attention. Under acidic tumor conditions, they exhibit targeted accumulation within tumor sites and controlled release profiles of therapeutic reagents, enabling precise tumor therapy.

AREAS COVERED

This review comprehensively summarize the principles underlying pH-responsive features, discussing various types of pH-responsive nanocarriers, their advantages, and limitations. Innovative therapeutic drugs are also examined, followed by an exploration of recent advancements in applying various pH-responsive nanocarriers as delivery systems for enhanced tumor therapy.

EXPERT OPINIONS

pH-responsive nanocarriers have garnered significant attention for their capability to achieve targeted accumulation of therapeutic agents at tumor sites and controlled drug delivery profiles, ultimately increasing the efficiency of tumor eradication. It is anticipated that the employment of pH-responsive nanocarriers will elevate the effectiveness and safety of tumor therapy, contributing to improved overall outcomes.

Stimuli-Responsive Polymeric Nanovaccines Toward Next-Generation Immunotherapy

The development of nanovaccines that employ polymeric delivery carriers has garnered substantial interest in therapeutic treatment of cancer and a variety of infectious diseases due to their superior biocompatibility, lower toxicity and reduced immunogenicity. Particularly, stimuli-responsive polymeric nanocarriers show great promise for delivering antigens and adjuvants to targeted immune cells, preventing antigen degradation and clearance, and increasing the uptake of specific antigen-presenting cells, thereby sustaining adaptive immune responses and improving immunotherapy for certain diseases. In this review, the most recent advances in the utilization of stimulus-responsive polymer-based nanovaccines for immunotherapeutic applications are presented. These sophisticated polymeric nanovaccines with diverse functions, aimed at therapeutic administration for disease prevention and immunotherapy, are further classified into several active domains, including pH, temperature, redox, light and ultrasound-sensitive intelligent nanodelivery systems. Finally, the potential strategies for the future design of multifunctional next-generation polymeric nanovaccines by integrating materials science with biological interface are proposed.

Ultrasound-targeted microbubble destruction remodels tumour microenvironment to improve immunotherapeutic effect

Cancer immunotherapy (CIT) has gained increasing attention and made promising progress in recent years, especially immune checkpoint inhibitors such as antibodies blocking programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4). However, its therapeutic efficacy is only 10-30% in solid tumours and treatment sensitivity needs to be improved. The complex tissue environment in which cancers originate is known as the tumour microenvironment (TME) and the complicated and dynamic TME is correlated with the efficacy of immunotherapy. Ultrasound-targeted microbubble destruction (UTMD) is an emerging technology that integrates diagnosis and therapy, which has garnered much traction due to non-invasive, targeted drug delivery and gene transfection characteristics. UTMD has also been studied to remodel TME and improve the efficacy of CIT. In this review, we analyse the effects of UTMD on various components of TME, including CD8⁺ T cells, tumour-infiltrating myeloid cells, regulatory T cells, natural killer cells and tumour vasculature. Moreover, UTMD enhances the permeability of the blood-brain barrier to facilitate drug delivery, thus improving CIT efficacy in vivo animal experiments. Based on this, we highlight the potential of immunotherapy against various cancer species and the clinical application prospects of UTMD.

An engineered hydrogel with low-dose antitumor drugs enhances tumor immunotherapy through tumor interstitial wrap

Stimulating immunogenic cell death (ICD) is the key to tumor immunotherapy. However, traditional chemoradiotherapy has limited effect on stimulating immunity and often requires repeated administration, which greatly reduces the tumor-killing effect. In this article, we created a sodium alginate hydrogel sustained-release system containing low-dose doxorubicin (Dox) and immune adjuvant R837, which were injected into the interstitial space to wrap around the tumor in situ, achieving a sustained release and long-lasting immune response. Cooperating with immune checkpoint blockade, Dox induced ICD, activated dendritic cells (DCs) and converted immunosuppressive M2-type tumor-associated macrophages (TAM) to tumor-killing M1-type TAMs. Simultaneously, it greatly promoted T cell proliferation and infiltration, and reduced tumor immunosuppressive factors, triggering a robust immune response to suppress tumors in vivo. In conclusion, this anti-tumor strategy based on interstitial injection can achieve continuous local immune stimulation by low-dose chemotherapy drugs, providing a potential approach for tumor immunotherapy.