Transcutaneous Codelivery of Tumor Antigen and Resiquimod in Solid-in-Oil Nanodispersions Promotes Antitumor Immunity

A bio-ionic liquid based self-healable and adhesive ionic hydrogel for the on-demand transdermal delivery of a chemotherapeutic drug

The non-invasive nature and potential for sustained release make transdermal drug administration an appealing treatment option for cancer therapy. However, the strong barrier of the stratum corneum (SC) poses a challenge for the penetration of hydrophilic chemotherapy drugs such as 5-fluorouracil (5-FU). Due to its biocompatibility and capacity to increase drug solubility and permeability, especially when paired with chemical enhancers, such as oleic acid (OA), which is used in this work, choline glycinate ([Cho][Gly]) has emerged as a potential substance for transdermal drug delivery. In this work, we examined the possibility of transdermal delivery of 5-FU for the treatment of breast cancer using an ionic hydrogel formulation consisting of [Cho][Gly] with OA. Small angle neutron scattering, rheological analysis, field emission scanning electron microscopy, and dynamic light scattering analysis were used to characterize the ionic hydrogel. The non-covalent interactions present between [Cho][Gly] and OA were investigated by computational simulations and FTIR spectroscopy methods. When subjected to in vitro drug permeation using goat skin in a Franz diffusion cell, the hydrogel demonstrated sustained release of 5-FU and effective permeability in the order: [Cho][Gly]-OA gel > [Cho][Gly] > PBS (control). The hydrogel also demonstrated 92% cell viability after 48 hours for the human keratinocyte cell line (HaCaT cells) as well as the normal human cell line L-132. The breast cancer cell line MCF-7 and the cervical cancer cell line HeLa were used to study in vitro cytotoxicity that was considerably affected by the 5-FU-loaded hydrogel. These results indicate the potential of the hydrogel as a transdermal drug delivery vehicle for the treatment of breast cancer.

Advancing immunotherapy using biomaterials to control tissue, cellular, and molecular level immune signaling in skin

Immunotherapies have been transformative in many areas, including cancer treatments, allergies, and autoimmune diseases. However, significant challenges persist in extending the reach of these technologies to new indications and patients. Some of the major hurdles include narrow applicability to patient groups, transient efficacy, high cost burdens, poor immunogenicity, and side effects or off-target toxicity that results from lack of disease-specificity and inefficient delivery. Thus, there is a significant need for strategies that control immune responses generated by immunotherapies while targeting infection, cancer, allergy, and autoimmunity. Being the outermost barrier of the body and the first line of host defense, the skin presents a unique immunological interface to achieve these goals. The skin contains a high concentration of specialized immune cells, such as antigen-presenting cells and tissue-resident memory T cells. These cells feature diverse and potent combinations of immune receptors, providing access to cellular and molecular level control to modulate immune responses. Thus, skin provides accessible tissue, cellular, and molecular level controls that can be harnessed to improve immunotherapies. Biomaterial platforms - microneedles, nano- and micro-particles, scaffolds, and other technologies - are uniquely capable of modulating the specialized immunological niche in skin by targeting these distinct biological levels of control. This review highlights recent pre-clinical and clinical advances in biomaterial-based approaches to target and modulate immune signaling in the skin at the tissue, cellular, and molecular levels for immunotherapeutic applications. We begin by discussing skin cytoarchitecture and resident immune cells to establish the biological rationale for skin-targeting immunotherapies. This is followed by a critical presentation of biomaterial-based pre-clinical and clinical studies aimed at controlling the immune response in the skin for immunotherapy and therapeutic vaccine applications in cancer, allergy, and autoimmunity.

Adrenergic receptor signaling regulates the CD40-receptor mediated anti-tumor immunity

Inroduction

Anti-CD40 agonistic antibody (αCD40), an activator of dendritic cells (DC) can enhance antigen presentation and activate cytotoxic T-cells against poorly immunogenic tumors. However, cancer immunotherapy trials also suggest that αCD40 is only moderately effective in patients, falling short of achieving clinical success. Identifying factors that decrease αCD40 immune-stimulating effects can aid the translation of this agent to clinical reality.

Method/Results

Here, we reveal that β-adrenergic signaling on DCs directly interferes with αCD40 efficacy in immunologically cold head and neck tumor model. We discovered that β-2 adrenergic receptor (β2AR) activation rewires CD40 signaling in DCs by directly inhibiting the phosphorylation of IκBα and indirectly by upregulating levels of phosphorylated-cAMP response element-binding protein (pCREB). Importantly, the addition of propranolol, a pan β-Blocker reprograms the CD40 pathways, inducing superior tumor regressions, increased infiltration of cytotoxic T-cells, and a reduced burden of regulatory T-cells in tumors compared to monotherapy.

Discussion/Conclusion

Thus, our study highlights an important mechanistic link between stress-induced β2AR signaling and reduced αCD40 efficacy in cold tumors, providing a new combinatorial approach to improve clinical outcomes in patients.

Tissue-adhesive hydrogel for multimodal drug release to immune cells in skin

Both innate and adaptive immune systems play a crucial role in the pathology of skin diseases. To control these cells, there is a need for transdermal drug delivery systems that can target multiple cell populations at independently tunable rates. Herein, we describe a tissue-adhesive hydrogel system that contains particles capable of regulating the release of small molecule drugs at defined rates. Resiquimod (a macrophage-targeting drug) and palbociclib (a T cell-targeting drug) are encapsulated within two types of silicone particles embedded within the hydrogel. We demonstrate that drug release is mediated by the crosslink density of the particles, which is decoupled from the bulk properties of the hydrogel. We show that this system can be used to sustainably polarize macrophages toward an anti-tumor phenotype in vitro and ex vivo, and that the hydrogels can remain attached to skin explants for several days without generating toxicity. The hydrogel system is compatible with standard dermatological procedures and allows transdermal passage of drugs. The multimodal, tunable nature of this system has implications in treating a variety of skin disorders, managing infections, and delivering vaccines. STATEMENT OF SIGNIFICANCE: We describe a tissue-adhesive hydrogel that can regulate the release of drugs in a manner that is decoupled from its bulk properties. The mechanism of drug release is mediated by embedded microparticles with well-defined crosslink densities. The significance of this system is that, by encapsulating different drugs into the particles, it is possible to achieve multimodal drug release. We demonstrate this capability by releasing two immunomodulatory drugs at disparate rates. A drug that targets innate immune cells is released quickly, and a drug that targets adaptive immune cells is released slowly. This programmable system offers a direct means by which cellular responses can be enhanced through independent targeting for a variety of transdermal applications, including cancer treatment and vaccine delivery.

Transdermal Delivery of Antigenic Protein Using Ionic Liquid-Based Nanocarriers for Tumor Immunotherapy

Transdermal drug delivery systems (TDDSs) may be useful for preventing various diseases including cancer. However, the stratum corneum (SC) inhibits the permeation of foreign particles into the skin. To obtain an effective TDDS, we developed a protein-containing nanocarrier (PCNC) comprising an antigenic protein (ovalbumin/OVA) stabilized by a combination of surfactants, i.e., a lipid-based surface-active ionic liquid and Tween-80. The PCNC was lyophilized to remove water and cyclohexane and then dispersed in isopropyl myristate. It is biocompatible both in vitro and in vivo, and is suitable for use in a therapeutic TDDS. The skin permeability of the PCNC was significantly (p < 0.0001) enhanced, and the transdermal distribution and transdermal flux of the OVA delivery system were 25 and 28 times greater, respectively, than those of its aqueous formulation. The PCNC disrupted the order of lipid orientation in the skin's SC and increased intercellular protein delivery. It demonstrated effective antitumor activity, drastically (p < 0.001) suppressed tumor growth, increased mouse survival rates, and significantly (p < 0.001) stimulated the OVA-specific tumor immune response. The PCNC also increased the number of cytotoxic T cells expressing CD8 antibodies on their surfaces (CD8 + T-cells) in the tumor microenvironment. These findings suggest that PCNCs may be promising biocompatible carriers for transdermal antigenic protein delivery in tumor immunotherapy.

Lyotropic liquid crystal-based transcutaneous peptide delivery system: Evaluation of skin permeability and potential for transcutaneous vaccination

Transcutaneous drug delivery is a promising method in terms of drug repositioning and reformulation because of its non-invasive and easy-to-use features. To overcome the skin barrier, which is the biggest challenge in transcutaneous drug delivery, a number of techniques, such as microemulsion, solid-in-oil dispersions and liposomes, have been studied extensively. However, the low viscosity of these formulations limits drug retention on the skin and reduces patient acceptability. Although viscosity can be increased by adding a thickening reagent, such an addition often alters formulation nanostructures and drug solubility, and importantly, decreases skin permeability. In this study, a gel-like lyotropic liquid crystal (LLC) was used as a tool to enhance skin permeability. In particular, we prepared 1-monolinolein (ML)-based LLCs with different water contents. All LLCs significantly enhanced skin permeation of a peptide drug, an epitope peptide of melanoma, despite their high viscoelasticity. Fourier transform infra-red spectroscopic analysis of the skin surface treated with the LLCs revealed that the gyroid geometry more strongly interacted with the lamellar structure inside the stratum corneum (SC) than the diamond geometry. Finally, as the result of the in vivo tumor challenge experiment using B16F10 melanoma-bearing mice, the LLC with the gyroid geometry showed stronger vaccine effect against tumor than a subcutaneous injection. Collectively, ML-based LLCs, especially with the gyroid geometry, are a promising strategy to deliver biomacromolecules into skin. STATEMENT OF SIGNIFICANCE: Transcutaneous drug delivery is a promising method for drug repositioning and reformulation because of its non-invasive and easy-to-use features. To overcome the skin barrier, which is the biggest challenge in transcutaneous drug delivery, we used a gel-like lyotropic liquid crystal (LLC) as a novel tool to enhance skin permeability. In this paper, we demonstrated that an LLC with a specific liquid crystalline structure has the highest skin permeation enhancement effect for a peptide antigen as a model drug. Moreover, the peptide antigen-loaded LLC showed a vaccine effect that was comparable to a subcutaneous injection in vivo. This study provides a basis for designing a transcutaneous delivery system of peptide drugs with LLC.

Transdermal Drug delivery: A step towards treatment of cancer

BACKGROUND

Transdermal drug delivery is an emerging and tempting system over oral and hypodermic drug delivery system. With the new developments in skin penetration techniques, anticancer drugs ranging from hydrophilic macromolecules to lipophilic drugs can be administered via transdermal route to treat cancer.

OBJECTIVE

In the present review, various approaches to enhance the transdermal delivery of drugs is discussed including the micro and nanotechnology based transdermal formulations like chemotherapy, gene therapy, immunotherapy, phototherapy, vaccines and medical devices. Limitations and advantages of various transdermal technologies is also elaborated.

METHOD

In this review, patent applications and recent literature of transdermal drug delivery systems employed to cure mainly cancer are covered.

RESULTS

Transdermal drug delivery systems have proved their potential to cure cancer. They increase the bioavailability of drug by site specific drug delivery and can reduce the side effects/toxicity associated with anticancer drugs.

CONCLUSION

The potential of transdermal drug delivery systems to carry the drug may unclutter novel ways for therapeutic intercessions in various tumors.

Formulation-based approaches for dermal delivery of vaccines and therapeutic nucleic acids: Recent advances and future perspectives

A growing variety of biological macromolecules are in development for use as active ingredients in topical therapies and vaccines. Dermal delivery of biomacromolecules offers several advantages compared to other delivery methods, including improved targetability, reduced systemic toxicity, and decreased degradation of drugs. However, this route of delivery is hampered by the barrier function of the skin. Recently, a large body of research has been directed toward improving the delivery of macromolecules to the skin, ranging from nucleic acids (NAs) to antigens, using noninvasive means. In this review, we discuss the latest formulation-based efforts to deliver antigens and NAs for vaccination and treatment of skin diseases. We provide a perspective of their advantages, limitations, and potential for clinical translation. The delivery platforms discussed in this review may provide formulation scientists and clinicians with a better vision of the alternatives for dermal delivery of biomacromolecules, which may facilitate the development of new patient-friendly prophylactic and therapeutic medicines.

Lipid-Based Ionic-Liquid-Mediated Nanodispersions as Biocompatible Carriers for the Enhanced Transdermal Delivery of a Peptide Drug

Lipid-based biocompatible ionic liquids (LBILs) have attracted attention as carriers in transdermal drug delivery systems (TDDSs) because of their lipophilic character. In this study, we report the formulation of a peptide-LBIL complex microencapsulated in an oil phase as a potential carrier for the transdermal delivery of leuprolide acetate as a model hydrophilic peptide. The peptide-LBIL complexes were prepared via a water-in-oil emulsion composed of 1,2-dimyristoyl-sn-glycerol-3-ethyl-phosphatidylcholine (EDMPC), a fatty acid (stearic, oleic, and linoleic acid)-based LBIL, and cyclohexane followed by freeze-drying to remove the water and cyclohexane. Then, the peptide-LBIL complexes were nanodispersed and stabilized in isopropyl myristate (IPM) using sorbitol laurate (Span-20). Ionic-liquid-in-oil nanodispersions (IL/O-NDs) were prepared with varying weight ratios of LBILs and Span-20 as the surfactant and the cosurfactant, respectively. Keeping the overall surfactant constant at 10 wt % in IPM, a 5:5 wt % ratio of surfactant (IL) and cosurfactant (Span-20) in the IL/O-NDs significantly (p < 0.0001) increased the physiochemical stability, drug-loading capacity, and drug encapsulation efficiency. The in vitro and in vivo peptide delivery across the skin was increased significantly (p < 0.0001) using IL/O-NDs, compared with non-IL-treated groups. Of all of the LBIL-based formulations, [EDMPC][Linoleate]/O-ND was considered the most preferable for a TDDS based on the pharmacokinetic parameters. The transdermal delivery flux with [EDMPC][Linoleate]/O-ND was increased 65-fold compared with the aqueous delivery vehicle. The IL/O-NDs were able to deform the lipid and protein arrangements of the skin layers to enhance the transdermal permeation of the peptide. In vitro and in vivo cytotoxicity studies of the IL/O-NDs revealed the biocompatibility of the LBIL-based formulations. These results indicated that IL/O-NDs are promising biocompatible carriers for lipid-peptide TDDSs.

Employing Drug Delivery Strategies to Overcome Challenges Using TLR7/8 Agonists for Cancer Immunotherapy

Toll-like receptors (TLRs) are a potential target for cancer immunotherapy due to their role in the activation of the innate immune system. More specifically, TLR7 and TLR8, two structurally similar pattern recognition receptors that trigger interferon and cytokine responses, have proven to be therapeutically relevant targets for cancer in numerous preclinical and clinical studies. When triggered by an agonist, such as imiquimod or resiquimod, the TLR7/8 activation pathway induces cellular and humoral immune responses that can kill cancer cells with high specificity. Unfortunately, TLR7/8 agonists also present a number of issues that must be overcome prior to broad clinical implementation, such as poor drug solubility and systemic toxic effects. To overcome the key limitations of TLR7/8 agonists as a cancer therapy, biomaterial-based drug delivery systems have been developed. These delivery devices are highly diverse in their design and include systems that can be directly administered to the tumor, passively accumulated in relevant cancerous and lymph tissues, triggered by environmental stimuli, or actively targeted to specific physiological areas and cellular populations. In addition to improved delivery systems, recent studies have also demonstrated the potential benefits of TLR7/8 agonist co-delivery with other types of therapies, particularly checkpoint inhibitors, cancer vaccines, and chemotherapeutics, which can yield impressive anti-cancer effects. In this review, we discuss recent advances in the development of TLR7/8 agonist delivery systems and provide perspective on promising future directions.

Biocompatible ionic liquids assisted transdermal co-delivery of antigenic protein and adjuvant for cancer immunotherapy

Human skin contains numerous antigen-presenting cells that are a potential target for several immune-based therapies, including vaccination and cancer immunotherapy. However, the outermost layer of the skin-the stratum corneum-acts as a major physical barrier against the permeation of antigens that have a molecular weight > 500 Da. In this study, an ionic liquid-assisted delivery system (ILDS) was developed, which enabled the successful transdermal delivery of an antigenic protein, ovalbumin (OVA), with a toll-like receptor agonist, imiquimod, as an adjuvant, to stimulate a specific immune response. Both the ionic liquids and ILDS were completely biocompatible for topical or transdermal application for therapeutic purposes. The skin permeation of the antigenic protein and adjuvant was found to be significantly enhanced because of the incorporation of a surface-active ionic liquid in the ILDS. An in vivo immunization study showed that there was a high level of OVA-specific IgG antibody production because of the enhanced permeation of the antigen and adjuvant across and into the skin. In a preclusive anticancer study, vaccination through ILDS showed stronger tumor-growth inhibition compared to control group. These results indicated that the ILDS could be a promising strategy for transdermal immunization as future therapeutics.

Transdermal Delivery Systems for Biomolecules

Purpose

The present review article focuses on highlighting the main technologies used as tools that improve the delivery of transdermal biomolecules, addressing them from the point of view of research in the development of transdermal systems that use physical and chemical permeation enhancers and nanocarrier systems or a combination of them.

Results

Transdermal drug delivery systems have increased in importance since the late 1970s when their use was approved by the Food and Drug Administration (FDA). They appeared to be an alternative resource for the administration of many potent drugs. The first transdermal drug delivery system used for biomolecules was for the treatment of hormonal disorders. Biomolecules have been used primarily in many treatments for cancer and diabetes, vaccines, hormonal disorders, and contraception.

Conclusions

The latest technologies that have used such transdermal biomolecule transporters include electrical methods (physical penetration enhancers), some chemical penetration enhancers and nanocarriers. All of them allow the maintenance of the physical and chemical properties of the main proteins and peptides through these clinical treatments, allowing their efficient storage, transport, and release and ensuring the achievement of their target and better results in the treatment of many diseases.

Graphical abstract

Advances in non and minimal-invasive transcutaneous delivery of immunotherapy for cancer treatment

Cancer research has focused on figuring out what was the difference between cancer cells and the tissues within which cancer arose and developing targeted treatments for those differences. With FDA-approved treatments for more ten different cancers and more than thousand new clinical trials, immunotherapy has recently emerged as the most promising area of cancer research by improving efficacy and controlling the adverse effects. Transcutaneous delivery drug delivery offers a number of advantages for the patient because of not only its noninvasive and convenient nature but also factors such as avoidance of first-pass metabolism and prevention of gastrointestinal degradation. The purpose of this review was to highlight technological recent approaches to non and minimal-invasive delivery of immunotherapy for cancer treatment. Finally, some practical considerations and discussions for future studies in the field of transdermal immunomodulation are also included.

Transcutaneous Delivery of Immunomodulating Pollen Extract-Galactomannan Conjugate by Solid-in-Oil Nanodispersions for Pollinosis Immunotherapy

Japanese cedar pollinosis is a type I allergic disease and has already become a major public health problem in Japan. Conventional subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) cannot meet patients' needs owing to the side effects caused by both the use of conventional whole antigen molecules in the pollen extract and the administration routes. To address these issues, a surface-modified antigen and transcutaneous administration route are introduced in this research. First, the pollen extract (PE) was conjugated to galactomannan (PE-GM) to mask immunoglobulin E (IgE)-binding epitopes in the PE to avoid side effects. Second, as a safer alternative to SCIT and SLIT, transcutaneous immunotherapy (TCIT) with a solid-in-oil (S/O) nanodispersion system carrying PE-GM was proposed. Hydrophilic PE-GM was efficiently delivered through mouse skin using S/O nanodispersions, reducing the antibody secretion and modifying the type 1 T helper (Th1)/ type 2 T helper (Th2) balance in the mouse model, thereby demonstrating the potential to alleviate Japanese cedar pollinosis.