A Squalene-Based Nanoemulsion for Therapeutic Delivery of Resiquimod

Enhanced Anticancer Effects Through Combined Therapeutic Model of Macrophage Polarization and Cancer Cell Apoptosis by Multifunctional Lipid Nanocomposites

Although the mono-anticancer therapy approach particularly directly targeting tumors is still common, this conventional method is generally deemed not effective and insufficient. In tumor microenvironment (TME), tumor-associated macrophages (TAMs, referred to as M2-polarized) play a crucial role in creating an immunosuppressive TME, contributing to various pro-tumorigenic effects. A promising strategy to inhibit tumor growth involves re-educating M2 macrophages into tumoricidal macrophages (M1). Therefore, combining macrophage reprogramming with cancer cell death induction in a single modality may offer synergistic benefits in cancer therapy. Here, we engineered a lipid-based delivery platform capable of co-delivering resiquimod (R848) and polyinosinic: polycytidylic acid (PIC). R848 in our nanosystem effectively triggered M2-to-M1 repolarization, as evidenced by the upregulation of M1 marker genes (TNF, IL6), the release of proinflammatory cytokines (TNF-α and IL-6), and the downregulation of the M2 marker gene, MRC1. On the other hand, the presence of PIC increased caspase-3/7 activity leading to cancer cell death through the apoptotic pathway. This nanocarrier system established a multifunctional platform to enhance the anticancer effect. The synergistic effect of repolarized macrophages in combination with the induction of apoptosis, facilitated by our nanomedicine, was evident in a co-culture system of macrophage and cancer cells, showing a significant increase in cancer cell death compared to individual treatments. These findings attractively demonstrated the potential of our multifunctional lipid nanoparticles as therapeutic agents for anticancer treatment by modulating the tumor immune microenvironment and simultaneously increasing cancer cell cytotoxicity.

All-Natural Gelatin-Based Nanoemulsion Loaded with TLR 7/8 Agonist for Efficient Modulation of Macrophage Polarization for Immunotherapy

Macrophages are multifunctional immune cells essential for both innate and adaptive immune responses. Tumor-associated macrophages (TAMs) often adopt a tumor-promoting M2-like phenotype, aiding tumor progression and immune evasion. Reprogramming TAMs to a tumoricidal M1-like phenotype is an emerging target for cancer immunotherapy. Resiquimod, a TLR7/8 agonist, can repolarize macrophages from the M2- to M1-like phenotype but is limited by poor solubility. We developed a gelatin nanoemulsion for the loading and delivery of resiquimod, utilizing eugenol oil as the liquid phase and riboflavin-crosslinked gelatin as a scaffold. These nanoemulsions showed high stability, low toxicity, and effective macrophage repolarization, significantly enhancing pro-inflammatory markers and anticancer activity in co-culture models.

Gender Control of Mouse Embryos by Activation of TLR7/8 on X Sperm via Ligands dsRNA-40 and dsRNA-DR

Gender control technologies are promising for enhancing the production efficiency of the farm animal industry, and preventing sex-linked hereditary diseases in humans. It has been shown that the X sperm of mammalian animals specifically expresses X-chromosome-derived toll-like receptor 7/8 (TLR7/8), and the activation of TLR7/8 on the X sperm by their agonist, R848, can separate X and Y sperm via the specific inhibition of X sperm motility. The use of R848-preselected sperm for fertilization resulted in sex-ratio-skewed embryos or offspring. In this study, we aimed to investigate whether two other TLR7/8 ligands, double-stranded RNA-40 (dsRNA-40) and double-stranded RNA-DR (dsRNA-DR), are also effective in the separation of mouse X and Y sperm and the subsequent generation of gender-ratio-skewed in vitro fertilization (IVF) embryos. Our results indicated that cholesterol modification significantly enhances the transfection of dsRNA-40 and dsRNA-DR into sperm cells. dsRNA-40 and dsRNA-DR incubation with mouse sperm could separate X and Y sperm by the specific suppression of X sperm motility by decreasing its ATP level and mitochondrial activity. The use of a dsRNA-40- or dsRNA-DR-preselected upper layer of sperm, which predominantly contains high-motility Y sperm, for IVF caused a male-biased sex ratio shift in resulting embryos (with 65.90-74.93% of embryos being male). This study develops a simple new method for the efficient separation of mammalian X and Y sperm, enabling the selective production of male or female progenies.

Lipid metabolism in tumor immunology and immunotherapy

Lipids are a diverse class of biomolecules that have been implicated in cancer pathophysiology and in an array of immune responses, making them potential targets for improving immune responsiveness. Lipid and lipid oxidation also can affect tumor progression and response to treatment. Although their importance in cellular functions and their potential as cancer biomarkers have been explored, lipids have yet to be extensively investigated as a possible form of cancer therapy. This review explores the role of lipids in cancer pathophysiology and describes how further understanding of these macromolecules could prompt novel treatments for cancer.

mRNA delivery in cancer immunotherapy

Messenger RNA (mRNA) has drawn much attention in the medical field. Through various treatment approaches including protein replacement therapies, gene editing, and cell engineering, mRNA is becoming a potential therapeutic strategy for cancers. However, delivery of mRNA into targeted organs and cells can be challenging due to the unstable nature of its naked form and the low cellular uptake. Therefore, in addition to mRNA modification, efforts have been devoted to developing nanoparticles for mRNA delivery. In this review, we introduce four categories of nanoparticle platform systems: lipid, polymer, lipid-polymer hybrid, and protein/peptide-mediated nanoparticles, together with their roles in facilitating mRNA-based cancer immunotherapies. We also highlight promising treatment regimens and their clinical translation.

Ivermectin Enhanced Antitumor Activity of Resiquimod in a Co-Loaded Squalene Emulsion

Immunogenic cell death (ICD) plays an important role in sensitizing tumor cells to antigen-presenting cells followed by antitumor immunity. However, a successful antitumor response by ICD requires both apoptotic tumor microenvironments and activated immune systems. Ivermectin (IVM) has been shown to induce cell apoptosis through autophagy which can be a great candidate for ICD therapy. However, a single treatment of IVM-free drug is not an ideal anticancer therapy due to its anti-inflammatory effects and cytotoxicity. In the present study, IVM was shown to enhance the ICD process in addition to the treatment of resiquimod (R848), a TLR7/8 agonist, when co-loaded in a squalene-based nanoemulsion (NE). R848-IVM co-loaded NE was developed and characterized in vitro. Antitumor activity of R848-IVM NE was also evaluated in vitro and in vivo. R848-IVM NE exhibited long-term stability and reduced cytotoxicity by IVM. In vivo studies demonstrated that IVM significantly augments the ICD by upregulating Cd8a and releasing HMGB1 in tumor tissue, which could enhance R848-driven antitumor immunity. R848-IVM NE treatment showed strong antitumor activity with over 80% tumor growth inhibition, suggesting a potential combination therapy of systemic co-delivering IVM with TLR agonists against solid cancer.

Investigation of Factors Influencing Formation of Nanoemulsion by Spontaneous Emulsification: Impact on Droplet Size, Polydispersity Index, and Stability

Interest in nanoemulsion technology has increased steadily in recent years for its widespread applications in the delivery of pharmaceuticals, nutraceuticals, and cosmeceuticals. Rational selection of the composition and the preparation method is crucial for developing a stable nanoemulsion system with desired physicochemical characteristics. In the present study, we investigate the influence of intricate factors including composition and preparation conditions that affect characteristic parameters and the stability of the nanoemulsion formation prepared by the spontaneous emulsification method. Octanoic acid, capryol 90, and ethyl oleate were selected to represent oil phases of different carbon–chain lengths. We explored the impact of the addition mode of the oil–S_mix phase and aqueous phase, vortexing time, K_m (surfactant/cosurfactant) ratio, and the replacement of water by buffers of different pH as an aqueous system. The phase behavior study showed that the S_mix phase had a significant impact on the nanoemulsifying ability of the nanoemulsions composed of oil phases of varying carbon-chain lengths. The mode of mixing of the oil–S_mix phase to the aqueous phase markedly influenced the mean droplet size and size distribution of the nanoemulsions composed of oil phases as capryol 90. Vortexing time also impacted the mean droplet size and the stability of the generated nanoemulsion system depending on the varying carbon-chain length of the oil phase. The replacement of the water phase by aqueous buffers of pH 1.2, 5.5, 6.8, and 7.4 has altered the mean droplet size and size distribution of the nanoemulsion system. Further, the K_m ratio also had a significant influence on the formation of the nanoemulsion system. The findings of this investigation are useful in understanding how the formulation composition and process parameters of the spontaneous emulsification technique are responsible for affecting the physicochemical characteristics and stability of the nanoemulsion system composed of oil of varying carbon-chain (C₈-C₁₈) length.

Application of lipid-based nanoparticles in cancer immunotherapy

Immunotherapy is revolutionizing the clinical management of patients with different cancer types by sensitizing autologous or allogenic immune cells to the tumor microenvironment which eventually leads to tumor cell lysis without rapidly killing normal cells. Although immunotherapy has been widely demonstrated to be superior to chemotherapies, only a few populations of patients with specific cancer types respond to such treatment due to the failure of systemic immune activation. In addition, severe immune-related adverse events are rapidly observed when patients with very few responses are given higher doses of such therapies. Recent advances of lipid-based nanoparticles (NPs) development have made it possible to deliver not only small molecules but also mRNAs to achieve systemic anticancer immunity through cytotoxic immune cell activation, checkpoint blockade, and chimeric antigen receptor cell therapies, etc. This review summarized recent development and applications of LNPs in anticancer immunotherapy. The diversity of lipid-based NPs would encapsulate payloads with different structures and molecular weights to achieve optimal antitumor immunity through multiple mechanisms of action. The discussion about the components of lipid-based NPs and their immunologic payloads in this review hopefully shed more light on the future direction of anticancer immunotherapy.