Application of BCG-CWS as a Systemic Adjuvant by Using Nanoparticulation Technology

Selective vascular disrupting therapy by lipid nanoparticle-mediated Fas ligand silencing and stimulation of STING

Although recent therapeutic developments have greatly improved the outcomes of patients with cancer, it remains on ongoing problem, particularly in relation to acquired drug resistance. Vascular disrupting agents (VDAs) directly damage tumor blood vessels, thus promoting drug efficacy and reducing the development of drug resistance; however, their low molecular weight and resulting lack of selectivity for tumor endothelial cells (TECs) lead to side effects that can hinder their practical use. Here, we report a novel tumor vascular disrupting therapy using nucleic acid-loaded lipid nanoparticles (LNPs). We prepared two LNPs: a small interfering RNA (siRNA) against Fas ligand (FasL)-loaded cyclic RGD modified LNP (cRGD-LNP) to knock down FasL in TECs and a stimulator of interferon genes (STING) agonist-loaded LNP to induce systemic type I interferon (IFN) production. The combination therapy disrupted the tumor vasculature and induced broad tumor cell apoptosis within 48 h, leading to rapid and strong therapeutic effects in various tumor models. T cells were not involved in these antitumor effects. Furthermore, the combination therapy demonstrated a significantly superior therapeutic efficacy compared with conventional anti-angiogenic agents and VDAs. RNA sequencing analysis suggested that reduced collagen levels may have been responsible for TEC apoptosis. These findings demonstrated a potential therapeutic method for targeting the tumor vasculature, which may contribute to the development of a new class of anti-cancer drugs.

Enhanced Immune Responses Against Mycobacterium tuberculosis Through Heat-Killed BCG with Squalene-in-water Emulsion Adjuvant

The increasing challenge of drug-resistant tuberculosis (TB) calls for the development of innovative therapeutic strategies, highlighting the potential of adjunctive immunotherapies that are both cost-effective and safe. Host-directed therapy (HDT) using immunomodulators shows promise in enhancing treatment efficacy by modulating immune responses, thereby shortening the duration of therapy and reducing drug resistance risks. This study investigated the immunomodulatory potential of combining Heat-killed Bacillus Calmette-Guérin (hBCG) with a Squalene-based oil-in-Water Emulsion (SWE) adjuvant against TB. The therapeutic efficacy of the hBCG-SWE regimen was assessed in a guinea pig model infected with Mycobacterium tuberculosis (M. tb). Furthermore, the impact of hBCG-SWE on TNF-α and MCP-1 production was evaluated in RAW264.7 macrophages, examining the role of TLR2/4 and MyD88 signaling pathways using ELISA, both with and without specific inhibitors. Our findings revealed that hBCG-SWE significantly enhanced TNF-α and MCP-1 production compared to hBCG alone, indicating activation through TLR2/4 and MyD88-dependent pathways. In guinea pigs, hBCG-SWE administration led to notable reductions in lung pathology and spleen bacterial loads versus control groups. These results highlight the capacity of hBCG-SWE to boost innate immunity and provide robust protection against M. tb. Future research should focus on evaluating the ability of hBCG-SWE to shorten conventional chemotherapy and exploring ways to amplify its immunomodulatory efficacy through advanced formulation techniques.

Recent Advances in the Development of Mincle-Targeting Vaccine Adjuvants

The Macrophage-inducible C-type lectin (Mincle) is a pattern-recognition receptor (PRR), which has shown much promise as a molecular target for the development of TH1/TH17-skewing vaccine adjuvants. In 2009, the first non-proteinaceous Mincle ligands, trehalose dimycolate (TDM) and trehalose dibehenate (TDB), were identified. This prompted a search for other Mincle agonists and the exploration of Mincle agonists as vaccine adjuvants for both preventative and therapeutic (anti-cancer) vaccines. In this review, we discuss those classes of Mincle agonists that have been explored for their adjuvant potential. These Mincle agonists have been used as stand-alone adjuvants or in combination with other pathogen-associated molecular patterns (PAMPs) or immunomodulatory agents. We will also highlight recently identified Mincle ligands with hitherto unknown adjuvanticity. Conjugate vaccines that contain covalently linked adjuvants and/or adjuvant-antigen combinations are also presented, as well as the different formulations (e.g., oil-in-water emulsions, liposomes, and particulate delivery systems) that have been used for the codelivery of antigens and adjuvants. Insofar the reader is presented with a thorough review of the potential of Mincle-mediated vaccine adjuvants, including historical context, present-day research and clinical trials, and outstanding research questions, such as the role of ligand presentation and Mincle clustering, which, if better understood, will aid in the development of the much-needed TH1/TH17-skewing vaccine adjuvants.

Clinical insights into nanomedicine and biosafety: advanced therapeutic approaches for common urological cancers

Urological cancers including those of the prostate, bladder, and kidney, are prevalent and often lethal malignancies besides other less common ones like testicular and penile cancers. Current treatments have major limitations like side effects, recurrence, resistance, high costs, and poor quality of life. Nanotechnology offers promising solutions through enhanced diagnostic accuracy, targeted drug delivery, controlled release, and multimodal imaging. This review reflects clinical challenges and nanomedical advances across major urological cancers. In prostate cancer, nanoparticles improve delineation and radiosensitization in radiation therapy, enable fluorescent guidance in surgery, and enhance chemotherapy penetration in metastatic disease. Nanoparticles also overcome bladder permeability barriers to increase the residence time of intravesical therapy and chemotherapy agents. In renal cancer, nanocarriers potentiate tyrosine kinase inhibitors and immunotherapy while gene vectors and zinc oxide nanoparticles demonstrate antiproliferative effects. Across modalities, urological applications of nanomedicine include polymeric, liposomal, and metal nanoparticles for targeted therapy, prodrug delivery, photodynamic therapy, and thermal ablation. Biosafety assessments reveal favorable profiles but clinical translation remains limited, necessitating further trials. In conclusion, nanotechnology holds significant potential for earlier detection, precise intervention, and tailored treatment of urological malignancies, warranting expanded research to transform patient outcomes.

Impact of in vivo fate of STING agonist-loaded lipid nanoparticles on antitumor immunity

Therapeutically manipulating the stimulator of interferon genes (STING) pathway has promising potential for enhancing antitumor immunity. Agonists of this pathway (STING agonists) are being evaluated in clinical trials. Loading the STING agonists into lipid nanoparticles (LNPs) increases their safety and efficacy. We previously developed STING agonists loaded LNPs consisting of the ionizable lipid YSK12-C4 (YSK12-LNPs), which showed significant antitumor effects. However, it is largely unclear how the in vivo fate of STING agonists loaded LNPs affects the antitumor immune responses. In this study, we compared the YSK12-LNPs with LNPs composed of DLin-MC3-DMA (MC3-LNPs) showing different in vivo fates. Biodistribution and flow cytometry analyses of mouse tissues revealed that the MC3-LNPs delivered higher amounts of STING agonists to the liver than the YSK12-LNPs. Additionally, significantly more liver leukocytes internalized the MC3-LNPs than the YSK12-LNPs. In contrast, the YSK12-LNPs delivered higher amounts of STING agonists to the liver leukocytes than the MC3-LNPs, leading to the effective induction of innate immunity and inflammation in the tumors. However, the antitumor effects in the B16-F10 lung metastasis and CT26 tumor models were comparable. Interestingly, flow cytometry analyses suggested that the YSK12-LNPs were more likely to activate natural killer cells and M1 macrophages, while the MC3-LNPs were more likely to activate CD8+ T cells. Our data suggest that different antitumor immune response mechanisms may operate depending on the characteristics and distribution of the LNPs.

Systemic versus localized Bacillus Calmette Guérin immunotherapy of bladder cancer promotes an anti-tumoral microenvironment: Novel role of trained immunity

Treatment for higher-risk non-muscle invasive bladder cancer (NMIBC) involves intravesical immunotherapy with Bacillus Calmette Guérin (BCG); however, disease recurrence and progression occur frequently. Systemic immunity is critical for successful cancer immunotherapy; thus, recurrence of NMIBC may be due to suboptimal systemic activation of anti-tumor immunity after local immunotherapy. We previously reported that systemically acquired trained immunity (a form of innate immune memory) in circulating monocytes is associated with increased time-to-recurrence in patients with NMIBC treated with BCG. Herein, we used a mouse model of NMIBC to compare the effects of intravesical versus intravenous (systemic) BCG immunotherapy on the local and peripheral immune microenvironments. We also assessed whether BCG-induced trained immunity modulates anti-tumor immune responses. Compared with intravesical BCG, which led to a tumor-promoting immune microenvironment, intravenous BCG resulted in an anti-tumoral bladder microenvironment characterized by increased proportions of cytotoxic T lymphocytes (CTLs), and decreased proportions of myeloid-derived suppressor cells. Polarization toward anti-tumoral immunity occurred in draining lymph nodes, spleen, and bone marrow following intravenous versus intravesical BCG treatment. Pre-treatment with intravesical BCG was associated with increased rate of tumor growth compared with intravenous BCG pre-treatment. Trained immunity contributed to remodeling of the tumor immune microenvironment, as co-instillation of BCG-trained macrophages with ovalbumin-expressing bladder tumor cells increased the proportion of tumor-specific CTLs. Furthermore, BCG-trained dendritic cells exhibited enhanced antigen uptake and presentation and promoted CTL proliferation. Our data support the concept that systemic immune activation promotes anti-tumor responses, and that BCG-induced trained immunity is important in driving anti-tumor adaptive immunity.

Nano-Bacillus Calmette-Guérin immunotherapies for improved bladder cancer treatment

Cancer immunotherapy has rapidly become the fourth mainstream treatment alternative after surgery, radiotherapy, and chemotherapy, with some promising results. It aims to kill tumor cells by mobilizing or stimulating cytotoxic immune cells. However, the clinical applications of tumor immunotherapies are limited owing to a lack of adequate delivery pathways and high toxicity. Recently, nanomaterials and genetic engineering have shown great potential in overcoming these limitations by protecting the delivery of antigens, activating targeted T cells, modulating the immunosuppressive tumor microenvironment, and improving the treatment efficacy. Bacillus Calmette-Guérin (BCG) is a live attenuated Mycobacterium bovis vaccine used to prevent tuberculosis, which was first reported to have antitumor activity in 1927. BCG therapy can activate the immune system by inducing various cytokines and chemokines, and its specific immune and inflammatory responses exert antitumor effects. BCG was first used during the 1970s as an intravesical treatment agent for bladder cancer, which effectively improved immune antitumor activity and prevented tumor recurrence. More recently, nano-BCG and genetically engineered BCG have been proposed as treatment alternatives for bladder cancer due to their ability to induce stronger and more stable immune responses. In this study, we outline the development of nano-BCG and genetically engineered BCG for bladder cancer immunotherapy and review their potential and associated challenges.

Exploiting bacterial-origin immunostimulants for improved vaccination and immunotherapy: current insights and future directions

Vaccination is a valid strategy to prevent and control newly emerging and reemerging infectious diseases in humans and animals. However, synthetic and recombinant antigens are poor immunogenic to stimulate efficient and protective host immune response. Immunostimulants are indispensable factors of vaccines, which can promote to trigger fast, robust, and long-lasting immune responses. Importantly, immunotherapy with immunostimulants is increasing proved to be an effective and promising treatment of cancer, which could enhance the function of the immune system against tumor cells. Pattern recognition receptors (PRRs) play vital roles in inflammation and are central to innate and adaptive immune responses. Toll-like receptors (TLRs)-targeting immunostimulants have become one of the hotspots in adjuvant research and cancer therapy. Bacterial-origin immunoreactive molecules are usually the ligands of PRRs, which could be fast recognized by PRRs and activate immune response to eliminate pathogens. Varieties of bacterial immunoreactive molecules and bacterial component-mimicking molecules have been successfully used in vaccines and clinical therapy so far. This work provides a comprehensive review of the development, current state, mechanisms, and applications of bacterial-origin immunostimulants. The exploration of bacterial immunoreactive molecules, along with their corresponding mechanisms, holds immense significance in deepening our understanding of bacterial pathogenicity and in the development of promising immunostimulants.

Elucidation of the Tissue Distribution and Host Immunostimulatory Activity of Exogenously Administered Probiotic-Derived Extracellular Vesicles for Immunoadjuvant

Extracellular vesicles (EVs) are cell-derived nanoparticles that can be used as novel biomaterials. In the development of EVs-based therapeutic systems, it is essential to understand the in vivo fate of exogenously administered EVs and subsequent biological responses mediated by EVs. Although probiotics and microorganisms that modulate the host immune system also secrete EVs, their tissue distribution and biological reactions after administration to the host have not been sufficiently elucidated. In this study, we characterized EVs released from the probiotics Bifidobacterium longum (B-EVs) and Lactobacillus plantarum WCFS1 (L-EVs) in terms of tissue distribution and immune-activating capacity after intravenous and subcutaneous administration in mice. B-EVs and L-EVs exhibited particle sizes of approximately 100-160 nm and negative zeta potentials. These EVs contained peptidoglycan, DNA, and RNA as their cargoes. Intravenously administered B-EVs and L-EVs mainly accumulated in the liver and spleen. Furthermore, liver F4/80 and splenic CD169 macrophages took up the intravenously administered EVs. Subcutaneously administered B-EVs and L-EVs accumulated in the lymph nodes and were mainly located in the B-lymphocyte zone, indicating that exogenously administered probiotic-derived EVs showed a similar biodistribution, irrespective of the EVs-secreting cell type. Evaluation of EVs-mediated immune reactions demonstrated that intravenously administered EVs showed little activation potency. In contrast, subcutaneously administered B-EVs strongly increased the expression of inflammatory cytokine (TNF-α) and co-stimulatory molecules (CD40 and CD80) than L-EVs. These findings indicate that the subcutaneous administration of B-EVs is a useful strategy for the development of novel EVs-based immunotherapies.

The Adjuvant Activity of BCG Cell Wall Cytoskeleton on a Dengue Virus-2 Subunit Vaccine

The uneven immunogenicity of the attenuated tetravalent dengue vaccine has made it difficult to achieve balanced protection against all four serotypes of the dengue virus (DENV). To overcome this problem, non-replicative vaccines have come into focus, as their immunogenicity is adjustable. This approach is excellent for multivalent vaccines but commonly faces the issue of low immunogenicity. In this present study, we developed a non-replicating dengue vaccine composed of UV-inactivated dengue virus-2 (UV-DENV-2) and DENV-2 NS1-279 protein encapsidated within nanoparticles. This vaccine candidate was administered in the presence of BCG cell wall cytoskeleton (BCG-CWS) as an adjuvant. We revealed, here, that encapsidated immunogens with BCG-CWS exerted potent activities on both B and T cells and elicited Th-1/Th-2 responses in mice. This was evidenced by BCG-CWS significantly augmenting antibody-mediated complement-fixing activity, strongly stimulating the antigen-specific polyfunctional T cell responses, and activating mixed Th-1/Th-2 responses specific to DENV-2- and NS1-279 antigens. In conclusion, BCG-CWS potently adjuvanted the inactivated DENV-2 and DENV subunit immunogens. The mechanism of adjuvanticity remains unclear. This study revealed the potential use of BCG-CWS in vaccine development.

Bacteria-based immunotherapy for cancer: a systematic review of preclinical studies

Immunotherapy has been emerging as a powerful strategy for cancer management. Recently, accumulating evidence has demonstrated that bacteria-based immunotherapy including naive bacteria, bacterial components, and bacterial derivatives, can modulate immune response via various cellular and molecular pathways. The key mechanisms of bacterial antitumor immunity include inducing immune cells to kill tumor cells directly or reverse the immunosuppressive microenvironment. Currently, bacterial antigens synthesized as vaccine candidates by bioengineering technology are novel antitumor immunotherapy. Especially the combination therapy of bacterial vaccine with conventional therapies may further achieve enhanced therapeutic benefits against cancers. However, the clinical translation of bacteria-based immunotherapy is limited for biosafety concerns and non-uniform production standards. In this review, we aim to summarize immunotherapy strategies based on advanced bacterial therapeutics and discuss their potential for cancer management, we will also propose approaches for optimizing bacteria-based immunotherapy for facilitating clinical translation.

Innovative System for Delivering Nucleic Acids/Genes Based on Controlled Intracellular Trafficking as Well as Controlled Biodistribution for Nanomedicines

This review paper summarizes progress that has been made in the new field of "Controlled Intracellular Trafficking." This involves the development of new systems for delivering plasmid DNA (pDNA), small interfering RNA (siRNA), mRNA, proteins, their escape from endosomes, the mechanism for how they enter the nucleus, how they enter mithochondria and how materials subsequently function within a cell. In addition, strategies for delivering these materials to a selective tissue after intravenous administration was also intensively investigated not only to the liver but also to tumors, lungs, adipose tissue and the spleen. In 2020, a new mRNA vaccine was developed against coronavirus disease 2019 (COVID-19), where ionizable cationic lipids were used as a delivery system. Our strategy to identify an efficient ionizable cationic lipids (iCL) based on a lipid library as well as their applications concerning the delivery of siRNA/mRNA/pDNA is also described.

State-of-the-Art Advances of Nanomedicine for Diagnosis and Treatment of Bladder Cancer

Bladder cancer is a common malignant tumor of the urinary system. Cystoscopy, urine cytology, and CT are the routine diagnostic methods. However, there are some problems such as low sensitivity and difficulty in staging, which must be urgently supplemented by novel diagnostic methods. Surgery, intravesical instillation, systemic chemotherapy, and radiotherapy are the main clinical treatments for bladder cancer. It is difficult for conventional treatment to deal with tumor recurrence, progression and drug resistance. In addition, the treatment agents usually have the defects of poor specific distribution ability to target tumor tissues and side effects. The rapid development of nanomedicine has brought hope for the treatment of bladder cancer in reducing side effects, enhancing tumor inhibition effects, and anti-drug resistance. Overall, we review the new progression of nano-platforms in the diagnosis and treatment of bladder cancer.

The future clinical implications of trained immunity

INTRODUCTION

Trained Immunity (TI) refers to the long-term modulation of the innate immune response, based on previous interactions with microbes, microbial ligands or endogenous substances. Through metabolic and epigenetic reprogramming, monocytes, macrophages and neutrophils develop an enhanced capacity to mount innate immune responses to subsequent stimuli and this is persistent due to alterations at the myeloid progenitor compartment.

AREAS COVERED

The purpose of this article is to review the current understanding of the TI process and discuss about its potential clinical implications in the near future. We address the evidence of TI involvement in various diseases, the currently developed new therapy, and discuss how TI may lead to new clinical tools to improve existing standards of care.

EXPERT OPINION

The state of art in this domain has made considerable progress, linking TI-related mechanisms in multiple immune-mediated pathologies, starting with infections to autoimmune disorders and cancers. As a relatively new area of immunology, it has seen fast progress with many of its applications ready to be investigated in clinical settings.

Innovative cancer nanomedicine based on immunology, gene editing, intracellular trafficking control

The recent rapid progress in the area of drug delivery systems (DDS) has opened a new era in medicine with a strong linkage to understanding the molecular mechanisms associated with cancer survival. In this review, we summarize new cancer strategies that have recently been developed based on our DDS technology. Cancer immunotherapy will be improved based on the concept of the cancer immunity cycle, which focuses on dynamic interactions between various types of cancer and immune cells in our body. The new technology of genome editing will also be discussed with reference to how these new DDS technologies can be used to introduce therapeutic cargoes into our body. Lastly, a new organelle, mitochondria will be the focus of creating a new cancer treatment strategy by a MITO-Porter which can deliver macromolecules directly to mitochondria of cancer cells via a membrane fusion approach and the impact of controlled intracellular trafficking will be discussed.

Novel molecules as the emerging trends in cancer treatment: an update

As per World Health Organization cancer remains as a leading killer disease causing nearly 10 million deaths in 2020. Since the burden of cancer increases worldwide, warranting an urgent search for anti-cancer compounds from natural sources. Secondary metabolites from plants, marine organisms exhibit a novel chemical and structural diversity holding a great promise as therapeutics in cancer treatment. These natural metabolites target only the cancer cells and the normal healthy cells are left unharmed. In the emerging trends of cancer treatment, the natural bioactive compounds have long become a part of cancer chemotherapy. In this review, we have tried to compile about eight bioactive compounds from plant origin viz. combretastatin, ginsenoside, lycopene, quercetin, resveratrol, silymarin, sulforaphane and withaferin A, four marine-derived compounds viz. bryostatins, dolastatins, eribulin, plitidepsin and three microorganisms viz. Clostridium, Mycobacterium bovis and Streptococcus pyogenes with their well-established anticancer potential, mechanism of action and clinical establishments are presented.

STING agonist loaded lipid nanoparticles overcome anti-PD-1 resistance in melanoma lung metastasis via NK cell activation

Background

Resistance to an immune checkpoint inhibitor (ICI) is a major obstacle in cancer immunotherapy. The causes of ICI resistance include major histocompatibility complex (MHC)/histocompatibility locus antigen (HLA) class I loss, neoantigen loss, and incomplete antigen presentation. Elimination by natural killer (NK) cells would be expected to be an effective strategy for the treatment of these ICI-resistant tumors. We previously demonstrated that a lipid nanoparticle containing a stimulator of an interferon gene (STING) agonist (STING-LNP) efficiently induced antitumor activity via the activation of NK cells. Thus, we evaluated the potential of reducing ICI resistance by STING-LNPs.

Methods

Lung metastasis of a B16-F10 mouse melanoma was used as an anti-programmed cell death 1 (anti-PD-1)-resistant mouse model. The mice were intravenously injected with the STING-LNP and the mechanism responsible for the improvement of anti-PD-1 resistance by the STING-LNPs was analyzed by RT-qPCR and flow cytometry. The dynamics of STING-LNP were also investigated.

Results

Although anti-PD-1 monotherapy failed to induce an antitumor effect, the combination of the STING-LNP and anti-PD-1 exerted a synergistic antitumor effect. Our results indicate that the STING-LNP treatment significantly increased the expression of CD3, CD4, NK1.1, PD-1 and interferon (IFN)-γ in lung metastases. This change appears to be initiated by the type I IFN produced by liver macrophages that contain the internalized STING-LNPs, leading to the systemic activation of NK cells that express PD-1. The activated NK cells appeared to produce IFN-γ, resulting in an increase in the expression of the PD ligand 1 (PD-L1) in cancer cells, thus leading to a synergistic antitumor effect when anti-PD-1 is administered.

Conclusions

We provide a demonstration to show that a STING-LNP treatment can overcome PD-1 resistance in a B16-F10 lung metastasis model. The mechanism responsible for this indicates that NK cells are activated by stimulating the STING pathway which, in turn, induced the expression of PD-L1 on cancer cells. Based on the findings reported herein, the STING-LNP represents a promising candidate for use in combination therapy with anti-PD-1-resistant tumors.

A Review on Cancer Immunotherapy and Applications of Nanotechnology to Chemoimmunotherapy of Different Cancers

Clinically, different approaches are adopted worldwide for the treatment of cancer, which still ranks second among all causes of death. Immunotherapy for cancer treatment has been the focus of attention in recent years, aiming for an eventual antitumoral effect through the immune system response to cancer cells both prophylactically and therapeutically. The application of nanoparticulate delivery systems for cancer immunotherapy, which is defined as the use of immune system features in cancer treatment, is currently the focus of research. Nanomedicines and nanoparticulate macromolecule delivery for cancer therapy is believed to facilitate selective cytotoxicity based on passive or active targeting to tumors resulting in improved therapeutic efficacy and reduced side effects. Today, with more than 55 different nanomedicines in the market, it is possible to provide more effective cancer diagnosis and treatment by using nanotechnology. Cancer immunotherapy uses the body's immune system to respond to cancer cells; however, this may lead to increased immune response and immunogenicity. Selectivity and targeting to cancer cells and tumors may lead the way to safer immunotherapy and nanotechnology-based delivery approaches that can help achieve the desired success in cancer treatment.

Liposome-Encapsulated Bacillus Calmette-Guérin Cell Wall Skeleton Enhances Antitumor Efficiency for Bladder Cancer In Vitro and In Vivo via Induction of AMP-Activated Protein Kinase

Simple Summary

We engineered novel nanoparticles consisting of liposome-encapsulated Bacillus Calmette–Guérin cell well skeleton (BCG-CWS) for intravesical instillation in bladder cancer. The liposome-encapsulated BCG-CWS nanoparticles had antitumoral effects in an orthotopic bladder cancer mouse model, and the BCG-CWS nanoparticles can be further developed as a non-toxic substitute for live BCG with improved dispensability, stability, and size compatibility. This is significant because we succeeded in the intravesical delivery of BCG-CWS through the intravesical route using a catheter in an orthotopic bladder cancer mouse model to specifically target tumor cells. This is the first study on the BCG-CWS-induced activation of AMPK in urothelial carcinoma cells, suggesting that AMPK-mediated reactive oxygen species (ROS) production and ER stress is a cellular signaling pathway in tumors sensitive to BCG-CWS. These results have the potential for significant ramifications in targeted therapy using a predictive marker for bladder cancer.

Abstract

The Mycobacterium Bacillus Calmette-Guérin cell wall skeleton (BCG-CWS), the main immune active center of BCG, is a potent candidate non-infectious immunotherapeutic drug and an alternative to live BCG for use against urothelial carcinoma. However, its application in anticancer therapy is limited, as BCG-CWS tends to aggregate in both aqueous and non-aqueous solvents. To improve the internalization of BCG-CWS into bladder cancer cells without aggregation, BCG-CWS was nanoparticulated at a 180 nm size in methylene chloride and subsequently encapsulated with conventional liposomes (CWS-Nano-CL) using an emulsified lipid (LEEL) method. In vitro cell proliferation assays showed that CWS-Nano-CL was more effective at suppressing bladder cancer cell growth compared to nonenveloped BCG-CWS. In an orthotopic implantation model of luciferase-tagged MBT2 bladder cancer cells, encapsulated BCG-CWS nanoparticles could enhance the delivery of BCG-CWS into the bladder and suppress tumor growth. Treatment with CWS-Nano-CL induced the inhibition of the mammalian target of rapamycin (mTOR) pathway and the activation of AMP-activated protein kinase (AMPK) phosphorylation, leading to apoptosis, both in vitro and in vivo. Furthermore, the antitumor activity of CWS-Nano-CL was mediated predominantly by reactive oxygen species (ROS) generation and AMPK activation, which induced endoplasmic reticulum (ER) stress, followed by c-Jun N-terminal kinase (JNK) signaling-mediated apoptosis. Therefore, our data suggest that the intravesical instillation of liposome-encapsulated BCG-CWS nanoparticles can facilitate BCG-CW cellular endocytosis and provide a promising drug-delivery system as a therapeutic strategy for BCG-mediated bladder cancer treatment.

Evolution of drug delivery system from viewpoint of controlled intracellular trafficking and selective tissue targeting toward future nanomedicine

Due to the rapid changes that have occurred in the field of drug discovery and the recent developments in the early 21st century, the role of drug delivery systems (DDS) has become increasingly more important. For the past 20 years, our laboratory has been developing gene delivery systems based on lipid-based delivery systems. One of our efforts has been directed toward developing a multifunctional envelope-type nano device (MEND) by modifying the particle surface with octaarginine, which resulted in a remarkably enhanced cellular uptake and improved intracellular trafficking of plasmid DNA (pDNA). When we moved to in vivo applications, however, we were faced with the PEG-dilemma and we shifted our strategy to the incorporation of ionizable cationic lipids into our system. This resulted in some dramatic improvements over our original design and this can be attributed to the development of a new lipid library. We have also developed a mitochondrial targeting system based on a membrane fusion mechanism using a MITO-Porter, which can deliver nucleic acids/pDNA into the matrix of mitochondria. After the appearance of antibody medicines, Opdivo, an immune checkpoint inhibitor, has established cancer immunology as the 4th strategy in cancer therapy. Our DDS technologies can also be applied to this new field of cancer therapy to cure cancer by controlling our immune mechanisms. The latest studies are summarized in this review article.

Mycobacteria-Based Vaccines as Immunotherapy for Non-urological Cancers

The arsenal against different types of cancers has increased impressively in the last decade. The detailed knowledge of the tumor microenvironment enables it to be manipulated in order to help the immune system fight against tumor cells by using specific checkpoint inhibitors, cell-based treatments, targeted antibodies, and immune stimulants. In fact, it is widely known that the first immunotherapeutic tools as immune stimulants for cancer treatment were bacteria and still are; specifically, the use of Mycobacterium bovis bacillus Calmette-Guérin (BCG) continues to be the treatment of choice for preventing cancer recurrence and progression in non-invasive bladder cancer. BCG and also other mycobacteria or their components are currently under study for the immunotherapeutic treatment of different malignancies. This review focuses on the preclinical and clinical assays using mycobacteria to treat non-urological cancers, providing a wide knowledge of the beneficial applications of these microorganisms to manipulate the tumor microenvironment aiming at tumor clearance.

Distribution of BCG-CWS-Loaded Nanoparticles in the Spleen After Intravenous Injection Affects Cytotoxic T Lymphocyte Activity

Interest has developed in the bacillus Calmette-Guerin (BCG) cell wall skeleton (BCG-CWS) as a noninfectious adjuvant. Although BCG-CWS readily undergoes aggregation, in a previous study, we applied it to cancer immunotherapy via intravenous administration by encapsulating the BCG-CWS into nanoparticles (CWS-NPs). The CWS-NPs were taken up by major histocompatibility complex (MHC) class II⁺ (MHC-II⁺) cells and induced antigen-specific cytotoxic T lymphocyte (CTL) activity. However, the nature of the contribution of MHC-II⁺ cells to the CTL response continues to be unclear. In this study, we investigated the relationship between the distribution of CWS-NPs in the spleen and CTL activity. The main MHC-II⁺ cells that internalized the CWS-NPs were B cells. Decreasing the level of polyethylene glycol modification increased the uptake of CWS-NPs by B cells, leading to an increased CTL activity. A comparison of CWS-NPs with different uptake efficiencies into dendritic cells and B cells suggested that the DCs with internalized CWS-NPs may contribute to CTL activation compared with B cells. We succeeded in enhancing CTL activity by the CWS-NPs, and the findings reported herein should provide important information regarding target cells for the development of CWS-NP.

Enhanced Intracellular Delivery of BCG Cell Wall Skeleton into Bladder Cancer Cells Using Liposomes Functionalized with Folic Acid and Pep-1 Peptide

Although bacillus Calmette–Guérin cell wall skeleton (BCG-CWS) might function as a potential substitute for live BCG, its use in the treatment of bladder cancer remains limited owing to issues such as insolubility and micrometer-size following exposure to an aqueous environment. Thus, to develop a novel nanoparticulate system for efficient BCG-CWS delivery, liposomal encapsulation was carried out using a modified emulsification-solvent evaporation method (targets: Size, <200 nm; encapsulation efficiency, ~60%). Further, the liposomal surface was functionalized with specific ligands, folic acid (FA), and Pep-1 peptide (Pep1), as targeting and cell-penetrating moieties, respectively. Functionalized liposomes greatly increased the intracellular uptake of BCG-CWS in the bladder cancer cell lines, 5637 and MBT2. The immunoactivity was verified through elevated cytokine production and a THP-1 migration assay. In vivo antitumor efficacy revealed that the BCG-CWS-loaded liposomes effectively inhibited tumor growth in mice bearing MBT2 tumors. Dual ligand-functionalized liposome was also superior to single ligand-functionalized liposomes. Immunohistochemistry supported the enhanced antitumor effect of BCG-CWS, with IL-6 production and CD4 infiltration. Thus, we conclude that FA- and Pep1-modified liposomes encapsulating BCG-CWS might be a good candidate for bladder cancer treatment with high target selectivity.

The silencing of indoleamine 2,3-dioxygenase 1 (IDO1) in dendritic cells by siRNA-loaded lipid nanoparticles enhances cell-based cancer immunotherapy

Cell-based therapy using dendritic cells (DC) represents a potent cancer immunotherapy. However, activated DC express indoleamine 2,3-dioxygenase 1 (IDO1), a counter-regulatory and tolerogenic molecule, leading to the inhibition of T cell activation and the promotion of T cell differentiation into regulatory T cells. Silencing the IDO1 gene in DC by small interfering RNA (siRNA) represents a potent therapeutic strategy. We report on the successful and efficient introduction of a siRNA targeting IDO1 into mouse DCs by a means of a multifunctional envelope-type nanodevice (MEND) containing a YSK12-C4 (YSK12-MEND). The YSK12-C4 has both fusogenic and cationic properties. The YSK12-MEND induced an effective level of gene silencing of IDO1 at siRNA doses in the range of 1–20 nM, a concentration that commercially available transfection reagents are not able to silence. The YSK12-MEND mediated IDO1 silencing had no effect on the characteristic determinants of DC phenotype such as CD11c, CD80 and MHC class II. The silencing of IDO1 in DC by the YSK12-MEND significantly enhanced the antitumor effect against E.G7-OVA tumor. Moreover, a decrease in the numbers of regulatory T cells in the tumor was observed in mice that were treated with the IDO1-silenced DC. The YSK12-MEND appears to be a potent delivery system for IDO1-silenced DC based cancer immunotherapy.

Conducting Polymeric Nanocomposites with a Three-Dimensional Co-flow Microfluidics Platform

The nanoprecipitation of polymers is of great interest in biological and medicinal applications. Many approaches are available, but few generalized methods can fabricate structurally different biocompatible polymers into nanosized particles with a narrow distribution in a high-throughput manner. We simply integrate a glass slide, capillary, and metal needle into a simple microfluidics device. Herein, a detailed protocol is provided for using the glass capillary and slides to fabricate the microfluidics devices used in this work. To demonstrate the generality of our nanoprecipitation approach and platform, four (semi)natural polymers—acetalated dextran (Ac-DEX), spermine acetalated dextran (Sp-Ac-DEX), poly(lactic-co-glycolic acid) (PLGA), and chitosan—were tested and benchmarked by the polymeric particle size and polydispersity. More importantly, the principal objective was to explore the influence of some key parameters on nanoparticle size due to its importance for a variety of applications. The polymer concentration, the solvent/non-solvent volume rate/ratio, and opening of the inner capillary were varied so as to obtain polymeric nanoparticles (NPs). Dynamic light scattering (DLS), transmission electron microscopy (TEM), and optical microscopy are the main techniques used to evaluate the nanoprecipitation output. It turns out that the concentration of polymer most strongly determines the particle size and distribution, followed by the solvent/non-solvent volume rate/ratio, whereas the opening of the inner capillary shows a minor effect. The obtained NPs were smooth spheres with adjustable particle diameters and polymer-dependent surface potentials, both negative and positive.