Systemic Immunotherapy with Micellar Resiquimod-Polymer Conjugates Triggers a Robust Antitumor Response in a Breast Cancer Model

Shifting cold to hot tumors by nanoparticle-loaded drugs and products

Cold tumors lack antitumor immunity and are resistant to therapy, representing a major challenge in cancer medicine. Because of the immunosuppressive spirit of the tumor microenvironment (TME), this form of tumor has a low response to immunotherapy, radiotherapy, and also chemotherapy. Cold tumors have low infiltration of immune cells and a high expression of co-inhibitory molecules, such as immune checkpoints and immunosuppressive molecules. Therefore, targeting TME and remodeling immunity in cold tumors can improve the chance of tumor repression after therapy. However, tumor stroma prevents the infiltration of inflammatory cells and hinders the penetration of diverse molecules and drugs. Nanoparticles are an intriguing tool for the delivery of immune modulatory agents and shifting cold to hot tumors. In this review article, we discuss the mechanisms underlying the ability of nanoparticles loaded with different drugs and products to modulate TME and enhance immune cell infiltration. We also focus on newest progresses in the design and development of nanoparticle-based strategies for changing cold to hot tumors. These include the use of nanoparticles for targeted delivery of immunomodulatory agents, such as cytokines, small molecules, and checkpoint inhibitors, and for co-delivery of chemotherapy drugs and immunomodulatory agents. Furthermore, we discuss the potential of nanoparticles for enhancing the efficacy of cancer vaccines and cell therapy for overcoming resistance to treatment.

Efficacy of MAGE-A4 long peptide as a universal immunoprevention cancer vaccine

BACKGROUND

The clinical application of peptide vaccines in tumor immunotherapy holds significant promise. Peptide-based tumor vaccines are currently subject to certain limitations in clinical trials, including the challenge of inducing a sustained response from CD4+ T helper cells and cytotoxic T lymphocytes (CTL), as well as human leukocyte antigen (HLA) restrictions.

METHODS

Through the utilization of biological information methodology, a screening process was conducted to identify three potential long peptides that are specifically targeted by the MAGE-A4 antigen. The candidate long peptides were subjected to in vitro testing using human peripheral blood lymphocytes as samples to evaluate their immunogenicity and immune function. The antitumor properties and preliminary mechanism of the long peptide vaccine were investigated through the use of a mouse model designed for the prevention of triple negative breast cancer (TNBC).

RESULTS

Three predicted multi-epitope long peptides targeting MAGE-A4 have shown to have a strong immunogenicity, with a total positive rate of 72% across different HLA subtypes in Chinese populations. they can also increase the levels of the costimulatory factor CD137 and tumor necrosis factor-alpha (TNF-α), activate T cells, and boost the cytotoxic activity. Results from an animal study have revealed that the long-peptide vaccine, both on its own and in combination with R848, has displayed impressive anti-tumor and target-specific capabilities. Moreover, it has the ability to increase the expression of effector memory T cells and central memory T cells.

CONCLUSIONS

This study was the first to screen three multi-epitope long peptides targeting MAGE-A4 and assess their immunogenicity, immune function, and potential as adjuvant peptides. The results showed that the MAGE-A4 long peptide vaccine can be used as a novel immunoprophylaxis method to prevent TNBC. Moreover, the proposed development model is capable of screening multiple target antigens, which lead to its clinical application.

Molecule engineering strategy of toll-like receptor 7/8 agonists designed for potentiating immune stimuli activation

Toll-like receptor 7/8 (TLR-7/8) agonists serve as a promising class of pattern recognition receptors that effectively evoke the innate immune response, making them promising immunomodulatory agents for tumor immunotherapy. However, the uncontrollable administration of TLR-7/8 agonists frequently leads to the occurrence of severe immune-related adverse events (irAEs). Thus, it is imperative to strategically design tumor-microenvironment-associated biomarkers or exogenous stimuli responsive TLR-7/8 agonists in order to accurately evaluate and activate innate immune responses. No comprehensive elucidation has been documented thus far regarding TLR-7/8 immune agonists that are specifically engineered to enhance immune activation. In this feature article, we provide an overview of the advancements in TLR-7/8 agonists, aiming to enhance the comprehension of their mechanisms and promote the clinical progression through nanomedicine strategies. The current challenges and future directions of cancer immunotherapy are also discussed, with the hope that this work will inspire researchers to explore innovative applications for triggering immune responses through TLR-7/8 agonists.

Molecular Masking of Synthetic Immunomodulator Evokes Antitumor Immunity With Reduced Immune Tolerance and Systemic Toxicity by Temporal Activity Recovery and Sustained Stimulation

Activation of the innate immune system counteracts tumor-induced immunosuppression. Hence, small molecule-based toll-like receptor 7/8 agonists (TLR7/8a), which can modulate immunosuppression in the tumor microenvironment along with the activation of innate immunity, are emerging as essential components of cancer immunotherapy. However, the clinical application of synthetic TLR7/8a therapies is limited by systemic immune-associated toxicity and immune tolerance induced by uncontrolled stimulatory activities and repeated treatments. To address these limitations, a dynamic immunomodulation strategy incorporating masking and temporal recovery of the activity of TLR7/8a through prodrug-like TLR7/8a (pro-TLR7/8a) at the molecular level and a sustained and controlled release of active TLR7/8a from nanoliposome (pro-TLR7/8a) (NL(pro-TLR7/8)) in a macroscale depot are designed. Immunization with cationic NL(pro-TLR7/8) and anionic antigens triggers robust activation of innate immune cells as well as antigen-specific T cell responses, eliciting reprogramming of immunosuppressive cells into tumor-suppressive cells, with decreased systemic adverse effects and immune tolerance. Combination treatment with NL(pro-TLR7/8a) and immune checkpoint inhibitors (anti-CTLA-4 plus anti-PD-L1) or nanoliposomes (Doxorubicin) has synergistic effects on antitumor immunity in various tumor models. The concept of pro-TLR7/8a suggested herein may facilitate the advancement of small-molecule-based immunomodulators for clinical translation and safe and effective cancer immunotherapy.

In situ sprayed hydrogels containing resiquimod-loaded liposomes reduce chronic osteomyelitis recurrence by intracellular bacteria clearance

At present, surgical debridement and systematic administration of antibiotics represent the mainstay of treatment for chronic osteomyelitis. However, it is now understood that Staphylococcus aureus (S. aureus) can survive within excessively polarized M2 macrophages and evade antibiotics, accounting for the high recurrence of chronic osteomyelitis. Effective treatments for intracellular infection have rarely been reported. Herein, we designed an in situ sprayed liposomes hydrogels spray with macrophage-targeted effects and the ability to reverse polarization and eradicate intracellular bacteria to reduce the recurrence of osteomyelitis. Resiquimod (R848)-loaded and phosphatidylserine (PS)-coating nanoliposomes were introduced into fibrinogen and thrombin to form the PSL-R848@Fibrin spray. Characterization and phagocytosis experiments were performed to confirm the successful preparation of the PSL-R848@Fibrin spray. Meanwhile, in vitro cell experiments validated its ability to eliminate intracellular S. aureus by reprogramming macrophages from the M2 to the M1 phenotype. Additionally, we established a chronic osteomyelitis rat model to simulate the treatment and recurrence process. Histological analysis demonstrated a significant increase in M1 macrophages and the elimination of intracellular bacteria. Imaging revealed a significant decrease in osteomyelitis recurrence. Overall, the liposome hydrogels could target macrophages to promote antibacterial properties against intracellular infection and reduce the recurrence of chronic osteomyelitis, providing the foothold for improving the outcomes of this patient population. STATEMENT OF SIGNIFICANCE: Chronic osteomyelitis remains a high recurrence although undergoing traditional treatment of debridement and antibiotics. S. aureus can survive within the excessively polarized M2 macrophages to evade the effects of antibiotics. However, few studies have sought to investigate effective intracellular bacteria eradication. Herein, we designed a macrophage-targeted R848-containing liposomes fibrin hydrogels spray (PSL-R848@Fibrin) that can reprogram polarization of macrophages and eradicate intracellular bacteria for osteomyelitis treatment. With great properties of rapid gelation, strong adhesion, high flexibility and fit-to-shape capacity, the facile-operated immunotherapeutic in-situ-spray fibrin hydrogels exhibited huge promise of reversing polarization and fighting intracellular infections. Importantly, we revealed a hitherto undocumented treatment strategy for reducing the recurrence of chronic osteomyelitis and potentially improving the prognosis of chronic osteomyelitis patients.

Engineered macromolecular Toll-like receptor agents and assemblies

Macromolecular Toll-like receptor (TLR) agents have been utilized as agonists and inhibitors in preclinical and clinical settings. These agents interface with the TLR class of innate immune receptors which recognize macromolecular ligands that are characteristic of pathogenic material. As such, many agents that have been historically investigated are derived from the natural macromolecules which activate or inhibit TLRs. This review covers recent research and clinically available TLR agents that are macromolecular or polymeric. Synthetic materials that have been found to interface with TLRs are also discussed. Assemblies of these materials are investigated in the context of improving stability or efficacy of ligands. Attention is given to strategies which modify or enhance the current agents and to future outlooks on the development of these agents.

Biodegradable nanomaterials for diagnosis and therapy of tumors

Although degradable nanomaterials have been widely designed and applied for cancer bioimaging and various cancer treatments, few reviews of biodegradable nanomaterials have been reported. Herein, we have summarized the representative research advances of biodegradable nanomaterials with respect to the mechanism of degradation and their application in tumor imaging and therapy. First, four kinds of tumor microenvironment (TME) responsive degradation are presented, including pH, glutathione (GSH), hypoxia and matrix metalloproteinase (MMP) responsive degradation. Second, external stimulation degradation is summarized briefly. Next, we have outlined the applications of nanomaterials in bioimaging. Finally, we have focused on some typical examples of biodegradable nanomaterials in radiotherapy (RT), photothermal therapy (PTT), starvation therapy, photodynamic therapy (PDT), chemotherapy, chemodynamic therapy (CDT), sonodynamic therapy (SDT), gene therapy, immunotherapy and combination therapy.

Engineered Living Bacteriophage-Enabled Self-Adjuvanting Hydrogel for Remodeling Tumor Microenvironment and Cancer Therapy

Due to the complexity and heterogeneity in the tumor microenvironment, the efficacy of breast cancer treatment has been significantly impeded. Here, we established a living system using an engineered M13 bacteriophage through chemical cross-linking and biomineralization to remodel the tumor microenvironment. Chemically cross-linking of the engineered bacteriophage gel (M13 Gel) could in situ synthesize photothermal palladium nanoparticles (PdNPs) on the pVIII capsid protein to obtain M13@Pd Gel. In addition, NLG919 was further loaded into a gel to form (M13@Pd/NLG gel) for down-regulating the expression of tryptophan metabolic enzyme indoleamine 2,3-dioxygenase 1 (IDO1). Both in vitro and in vivo studies showed that the M13 bacteriophage served not only as a cargo-loaded device but also as a self-immune adjuvant, which induced the immunogenic death of tumor cells effectively and down-regulated IDO1 expression. Such a bioactive gel system constructed by natural living materials could reverse immunosuppression and significantly improve the anti-breast cancer response.

Combined Biomimetic MOF-RVG15 Nanoformulation Efficient Over BBB for Effective Anti-Glioblastoma in Mice Model

Introduction

The blood-brain barrier (BBB) is a key obstacle to the delivery of drugs into the brain. Therefore, it is essential to develop an advanced drug delivery nanoplatform to solve this problem. We previously screened a small rabies virus glycoprotein 15 (RVG15) peptide with 15 amino acids and observed that most of the RVG15-modified nanoparticles entered the brain within 1 h of administration. The high BBB penetrability gives RVG15 great potential for brain-targeted drug delivery systems. Moreover, a multifunctional integrated nanoplatform with a high drug-loading capacity, tunable functionality, and controlled drug release is crucial for tumor treatment. Zeolitic imidazolate framework (ZIF-8) is a promising nanodrug delivery system.

Methods

Inspired by the biomimetic concept, we designed RVG15-coated biomimetic ZIF-8 nanoparticles (RVG15-PEG@DTX@ZIF-8) for docetaxel (DTX) delivery to achieve efficient glioblastoma elimination in mice. This bionic nanotherapeutic system was prepared by one-pot encapsulation, followed by coating with RVG15-PEG conjugates. The size, morphology, stability, drug-loading capacity, and release of RVG15-PEG@DTX@ZIF-8 were thoroughly investigated. Additionally, we performed in vitro evaluation, cell uptake capacity, BBB penetration, and anti-migratory ability. We also conducted an in vivo evaluation of the biodistribution and anti-glioma efficacy of this bionic nanotherapeutic system in a mouse mode.

Results

In vitro studies showed that, this bionic nanotherapeutic system exhibited excellent targeting efficiency and safety in HBMECs and C6 cells and high efficiency in crossing the BBB. Furthermore, the nanoparticles cause rapid DTX accumulation in the brain, allowing deeper penetration into glioma tumors. In vivo antitumor assay results indicated that RVG15-PEG@DTX@ZIF-8 significantly inhibited glioma growth and metastasis, thereby improving the survival of tumor-bearing mice.

Conclusion

Our study demonstrates that our bionic nanotherapeutic system using RVG15 peptides is a promising and powerful tool for crossing the BBB and treating glioblastoma.

Emerging advances in nanomedicine for breast cancer immunotherapy: opportunities and challenges

Breast cancer is one of the most common causes of cancer-related morbidity and mortality in women worldwide. Early diagnosis and an appropriate therapeutic approach for all cancers are climacterics for a favorable prognosis. Targeting the immune system in breast cancer is already a clinical reality with notable successes, specifically with checkpoint blockade antibodies and chimeric antigen receptor T-cell therapy. However, there have been inevitable setbacks in the clinical application of cancer immunotherapy, including inadequate immune responses due to insufficient delivery of immunostimulants to immune cells and uncontrolled immune system modulation. Rapid advancements and new evidence have suggested that nanomedicine-based immunotherapy may be a viable option for treating breast cancer.

Tumor-associated macrophages: Potential target of natural compounds for management of breast cancer

A large body of experimental research reveals that tumor-associated macrophages (TAMs) are the major immunosuppressor cells in the breast tumor microenvironment (TME). The infiltration of macrophages is correlated with inverse outcomes like disease-free survival and overall survival of cancer patients. They are responsible for heterogeneity, metastasis, and drug resistance. Further, their density in tumor beds is correlated with stage and therapy response. The current review is aimed at summarizing mechanisms and signaling pathways that modulate immune-suppressive phenotype and expansion of TAMs. The review presents an overview of the interdependence of tumor cells and TAMs in TME to promote metastasis, drug resistance and immune suppressive phenotype. This review also presents the potential natural compounds that modulate the immune-suppressive functions of TAMs and their signaling pathways. Finally, this review provides nanotechnology approaches for the targeted delivery of natural products. This review shed light on BC management including clinical studies on the prognostic relevance of TAMs and natural compounds that sensitizes BC.

Engineering immunomodulatory nanoplatforms from commensal bacteria-derived polysaccharide A

Capsular zwitterionic polysaccharides (CZPs), typically found on the surfaces of commensal gut bacteria, are important immunomodulatory molecules due to their ability to produce a T cell dependent immune response upon processing by antigen presenting cells (APCs). Their immunological activity makes them potentially useful for generating material constructs that are applicable for the treatment of diseases, or as vaccines. Herein, we explored synthetic strategies to generate immunologically active polymer-carbohydrate conjugates and nanomaterials of the CZP, Polysaccharide A (PSA) derived from Bacteroides fragilis. Initially, we addressed the purification of PSA, which is critical for the realization of materials applicable for biomedical purposes. Anion exchange high performance liquid chromatography in the presence of a surfactant (CHAPS) enabled the isolation of pure PSA. Through modification of purified PSA with azide groups, we demonstrated that polymers or antigens could be incorporated with PSA via click chemistry reactions to generate conjugates that can be fabricated into nanoparticles. By conjugation of PSA with a DBCO end functionalized polyphosphoester polymer with hydrophobic pendant terminal alkyne groups, an amphiphilic conjugate was obtained which formed nanoparticles of about 100 nm in aqueous solution. Moreover, terminal alkyne groups could be modified with charged thiol molecules (amine/carboxylate) via thiol-yne radical chemistry to generate conjugates, which could be incorporated into nanoparticles via electrostatic interactions building onto a charged nanoparticle template. The conjugates and nanoparticles exhibited immunological activity as assessed by the toll-like receptor 2 (TLR2) activation assay and positive cytokine production (IL-10) following their co-incubation with APCs and T cells. Summarily, this work plainly demonstrates chemical biology strategies for fabricating immunomodulatory nanomaterials from commensal microorganisms that can potentially be novel vaccines or immunotherapeutics.

A Squalene-Based Nanoemulsion for Therapeutic Delivery of Resiquimod

Agonists for toll-like receptors (TLRs) have shown promising activities against cancer. In the present study, a squalene-based nanoemulsion (NE) was loaded with resiquimod, a TLR7/8 agonist for therapeutic delivery. R848 NE was developed and characterized for long-term stability. In vitro and in vivo antitumor immunity of R848 NE were also evaluated in combination with SD-101, a CpG-containing TLR9 agonist. In vitro studies demonstrated strong long-term stability and immune responses to R848 NE. When combined with SD-101, strong antitumor activity was observed in MC38 murine colon carcinoma model with over 80% tumor growth inhibition. The combination treatment showed a 4-fold increase in systemic TNFa production and a 2.6-fold increase in Cd8a expression in tumor tissues, suggesting strong cell-mediated immune responses against the tumor. The treatment not only demonstrated a strong antitumor immunity by TLR7/8 and TLR9 activations but also induced PD-L1 upregulation in tumors, suggesting a potential therapeutic synergy with immune checkpoint inhibitors.