Cascade Cytosol Delivery of Dual-Sensitive Micelle-Tailored Vaccine for Enhancing Cancer Immunotherapy

Nanoparticles in tumor microenvironment remodeling and cancer immunotherapy

Cancer immunotherapy and vaccine development have significantly improved the fight against cancers. Despite these advancements, challenges remain, particularly in the clinical delivery of immunomodulatory compounds. The tumor microenvironment (TME), comprising macrophages, fibroblasts, and immune cells, plays a crucial role in immune response modulation. Nanoparticles, engineered to reshape the TME, have shown promising results in enhancing immunotherapy by facilitating targeted delivery and immune modulation. These nanoparticles can suppress fibroblast activation, promote M1 macrophage polarization, aid dendritic cell maturation, and encourage T cell infiltration. Biomimetic nanoparticles further enhance immunotherapy by increasing the internalization of immunomodulatory agents in immune cells such as dendritic cells. Moreover, exosomes, whether naturally secreted by cells in the body or bioengineered, have been explored to regulate the TME and immune-related cells to affect cancer immunotherapy. Stimuli-responsive nanocarriers, activated by pH, redox, and light conditions, exhibit the potential to accelerate immunotherapy. The co-application of nanoparticles with immune checkpoint inhibitors is an emerging strategy to boost anti-tumor immunity. With their ability to induce long-term immunity, nanoarchitectures are promising structures in vaccine development. This review underscores the critical role of nanoparticles in overcoming current challenges and driving the advancement of cancer immunotherapy and TME modification.

The significance of targeting lysosomes in cancer immunotherapy

Lysosomes are intracellular digestive organelles that participate in various physiological and pathological processes, including the regulation of immune checkpoint molecules, immune cell function in the tumor microenvironment, antigen presentation, metabolism, and autophagy. Abnormalities or dysfunction of lysosomes are associated with the occurrence, development, and drug resistance of tumors. Lysosomes play a crucial role and have potential applications in tumor immunotherapy. Targeting lysosomes or harnessing their properties is an effective strategy for tumor immunotherapy. However, the mechanisms and approaches related to lysosomes in tumor immunotherapy are not fully understood at present, and further basic and clinical research is needed to provide better treatment options for cancer patients. This review focuses on the research progress related to lysosomes and tumor immunotherapy in these.

Biomimetic virus-like mesoporous silica nanoparticles improved cellular internalization for co-delivery of antigen and agonist to enhance Tumor immunotherapy

Nanocarrier antigen-drug delivery system interacts specifically with immune cells and provides intelligent delivery modes to improve antigen delivery efficiency and facilitate immune progression. However, these nanoparticles often have weak adhesion to cells, followed by insufficient cell absorption, leading to a failed immune response. Inspired by the structure and function of viruses, virus-like mesoporous silica nanoparticles (VMSNs) were prepared by simulating the surface structure, centripetal-radialized spike structure and rough surface topology of the virus and co-acted with the toll-like receptor 7/8 agonist imiquimod (IMQ) and antigens oocyte albumin (OVA). Compared to the conventional spherical mesoporous silica nanoparticles (MSNs), VMSNs which was proven to be biocompatible in both cellular and in vivo level, had higher cell invasion ability and unique endocytosis pathway that was released from lysosomes and promoted antigen cross-expression. Furthermore, VMSNs effectively inhibited B16-OVA tumor growth by activating DCs maturation and increasing the proportion of CD8⁺ T cells. This work demonstrated that virus-like mesoporous silica nanoparticles co-supply OVA and IMQ, could induce potent tumor immune responses and inhibit tumor growth as a consequence of the surface spike structure induces a robust cellular immune response, and undoubtedly provided a good basis for further optimizing the nanovaccine delivery system.

Advances in Polymeric Micelles: Responsive and Targeting Approaches for Cancer Immunotherapy in the Tumor Microenvironment

In recent years, to treat a diverse array of cancer forms, considerable advancements have been achieved in the field of cancer immunotherapies. However, these therapies encounter multiple challenges in clinical practice, such as high immune-mediated toxicity, insufficient accumulation in cancer tissues, and undesired off-target reactions. To tackle these limitations and enhance bioavailability, polymer micelles present potential solutions by enabling precise drug delivery to the target site, thus amplifying the effectiveness of immunotherapy. This review article offers an extensive survey of recent progress in cancer immunotherapy strategies utilizing micelles. These strategies include responsive and remodeling approaches to the tumor microenvironment (TME), modulation of immunosuppressive cells within the TME, enhancement of immune checkpoint inhibitors, utilization of cancer vaccine platforms, modulation of antigen presentation, manipulation of engineered T cells, and targeting other components of the TME. Subsequently, we delve into the present state and constraints linked to the clinical utilization of polymeric micelles. Collectively, polymer micelles demonstrate excellent prospects in tumor immunotherapy by effectively addressing the challenges associated with conventional cancer immunotherapies.

Advanced subunit vaccine delivery technologies: From vaccine cascade obstacles to design strategies

Designing and manufacturing safe and effective vaccines is a crucial challenge for human health worldwide. Research on adjuvant-based subunit vaccines is increasingly being explored to meet clinical needs. Nevertheless, the adaptive immune responses of subunit vaccines are still unfavorable, which may partially be attributed to the immune cascade obstacles and unsatisfactory vaccine design. An extended understanding of the crosstalk between vaccine delivery strategies and immunological mechanisms could provide scientific insight to optimize antigen delivery and improve vaccination efficacy. In this review, we summarized the advanced subunit vaccine delivery technologies from the perspective of vaccine cascade obstacles after administration. The engineered subunit vaccines with lymph node and specific cell targeting ability, antigen cross-presentation, T cell activation properties, and tailorable antigen release patterns may achieve effective immune protection with high precision, efficiency, and stability. We hope this review can provide rational design principles and inspire the exploitation of future subunit vaccines.

Advances in Cancer Nanovaccines: Harnessing Nanotechnology for Broadening Cancer Immune Response

Many advances have been made recently in the field of cancer immunotherapy, particularly with the development of treatments such as immune checkpoint inhibitors and adoptive cellular immunotherapy. The efficacy of immunotherapy is limited, however, owing to high levels of tumor heterogeneity and the immunosuppressive environments of advanced malignant tumors. Therefore, therapeutic anticancer vaccines have gradually become powerful tools for inducing valid antitumor immune responses and regulating the immune microenvironment. Tumor vaccines loaded in nanocarriers have become an indispensable delivery platform for tumor treatment because of their enhanced stability, targeting capability, and high level of safety. Through a unique design, cancer nanovaccines activate innate immunity and tumor-specific immunity simultaneously. For example, the design of cancer vaccines can incorporate strategies such as enhancing the stability and targeting of tumor antigens, combining effective adjuvants, cytokines, and immune microenvironment regulators, and promoting the maturation and cross-presentation of antigen-presenting cells (APCs). In this review, we discuss the design and preparation of nanovaccines for remodeling tumor antigen immunogenicity and regulating the immunosuppressive microenvironment.

Enhancement of Immune Responses Elicited by Nanovaccines through a Cross-Presentation Pathway

Numerous studies have aimed to develop novel advanced vaccines, in part because traditional vaccines have been unsuccessful in preventing rapidly emerging and reemerging viral and bacterial infections. There is a need for an advanced vaccine delivery system to ensure the successful induction of humoral and cellular immune responses. In particular, the ability of nanovaccines to modulate intracellular antigen delivery by inducing exogenous antigens (loaded onto major histocompatibility complex class 1 molecules) in CD8⁺ T cells, the so-called cross-presentation pathway, has attracted a great deal of attention. Protection against viral and intracellular bacterial infections relies on cross-presentation. This review discusses the advantages, requirements, and preparation of nanovaccines, the cross-presentation mechanism, the several parameters affecting cross-presentation by nanovaccines, and future perspectives.

Regulating T-cell metabolic reprogramming and blocking PD-1 co-promote personalized postoperative autologous nanovaccines

Cytotoxic T lymphocytes (CTLs) are central effector cells in antitumor immunotherapy. However, the complexity of immunosuppressive factors in the immune system contributes to the low response rates of current CTL-based immunotherapies. Here, we propose a novel holistic strategy including a priming response, promoting activity, and relieving suppression of CTLs, aiming to strengthen the effect of personalized postoperative autologous nanovaccines. The nanovaccine (C/G-HL-Man) fused the autologous tumor cell membrane with dual adjuvants (CpG and cGAMP), and could effectively accumulate in lymph nodes and promote antigen cross presentation by dendritic cells to prime a sufficient specific-CTL response. The PPAR-α agonist fenofibrate was used to regulate T-cell metabolic reprogramming to promote antigen-specific CTLs activity in the harsh metabolic tumor microenvironment. Finally, the PD-1 antibody was used to relieve the suppression of specific-CTLs in the immunosuppressive tumor microenvironment. In vivo, the C/G-HL-Man exhibited strong antitumor effect in the B16F10 murine tumor prevention model and the B16F10 postoperative recurrence model. In particular, combination therapy with nanovaccines, fenofibrate, and PD-1 antibody effectively inhibited the progression of recurrent melanoma and prolonged the survival time. Our work highlights the critical role of the T-cell metabolic reprogramming and PD-1 blocking in autologous nanovaccines, offering a novel strategy for strengthening the function of CTLs.

Polymeric micelles and cancer therapy: an ingenious multimodal tumor-targeted drug delivery system

Since the beginning of pharmaceutical research, drug delivery methods have been an integral part of it. Polymeric micelles (PMs) have emerged as multifunctional nanoparticles in the current technological era of nanocarriers, and they have shown promise in a range of scientific fields. They can alter the release profile of integrated pharmacological substances and concentrate them in the target zone due to their improved permeability and retention, making them more suitable for poorly soluble medicines. With their ability to deliver poorly soluble chemotherapeutic drugs, PMs have garnered considerable interest in cancer. As a result of their remarkable biocompatibility, improved permeability, and minimal toxicity to healthy cells, while also their capacity to solubilize a wide range of drugs in their micellar core, PMs are expected to be a successful treatment option for cancer therapy in the future. Their nano-size enables them to accumulate in the tumor microenvironment (TME) via the enhanced permeability and retention (EPR) effect. In this review, our major aim is to focus primarily on the stellar applications of PMs in the field of cancer therapeutics along with its mechanism of action and its latest advancements in drug and gene delivery (DNA/siRNA) for cancer, using various therapeutic strategies such as crossing blood-brain barrier, gene therapy, photothermal therapy (PTT), and immunotherapy. Furthermore, PMs can be employed as "smart drug carriers," allowing them to target specific cancer sites using a variety of stimuli (endogenous and exogenous), which improve the specificity and efficacy of micelle-based targeted drug delivery. All the many types of stimulants, as well as how the complex of PM and various anticancer drugs react to it, and their pharmacodynamics are also reviewed here. In conclusion, commercializing engineered micelle nanoparticles (MNPs) for application in therapy and imaging can be considered as a potential approach to improve the therapeutic index of anticancer drugs. Furthermore, PM has stimulated intense interest in research and clinical practice, and in light of this, we have also highlighted a few PMs that have previously been approved for therapeutic use, while the majority are still being studied in clinical trials for various cancer therapies.

Self-assembled D-arginine derivatives based on click chemical reactions for intracellular codelivery of antigens and adjuvants for potential immunotherapy

Self-assembled amino acid derivatives could form well-defined nanostructures which have great application value for drug delivery systems. In particular, D-amino acid derivatives possess tremendous advantages including anti-degradation and good lysosome escape compared with L-amino acid derivatives. In this work, 9-fluorenylmethyloxycarbonyl (Fmoc) neighboring D-arginine derivatives were replaced by dibenzocyclooctyne (DBCO) to extend the class of functional D-arginine derivatives, which were further reacted with various cross-linkers including azide to construct a library of self-assembled supramolecular nanovehicles and strengthen the stability of nanostructures for disease immunotherapy. Moreover, in vitro studies demonstrated that the combination of DBCO modified D-arginine derivative DR3 and cross-linker C1 not only reinforced the cellular uptake efficiency of ovalbumin (OVA) which was chosen as the model antigen, but also promoted the cytokine TNF-α release of RAW 264.7 cells after the introduction of adjuvant unmethylated cytosine-phosphate-guanine dinucleotides (CpG). Furthermore, the nanovaccine based on DR3C1 could enhance the antigen OVA and adjuvant cytosolic delivery of marrow derived dendritic cells (BMDCs), which improved the antigen-presentation cross efficiency and induced the maturation of BMDCs. Taken together, we believe that D-arginine derivatives functionalized by DBCO provide an effective strategy for disease immunotherapy and act as a great potential delivery tool.

Application of "smart" multifunctional nanoprobes in tumor diagnosis and treatment

Cancer is one of the major diseases that pose a threat to human health and life, especially because it is difficult to diagnose and cure, and recurs easily. In recent years, the development of nanotechnology has provided researchers with new tools for cancer treatment. In particular, nanoprobes that facilitate integrated diagnosis and treatment, high-resolution imaging, and accurate tumor targeting provide new avenues for the early detection and treatment of cancer. This review focuses on the preparations and applications of two kinds of "smart" multifunctional nanoprobes: "Off-On" nanoprobes and "Charge-Reversal" nanoprobes. This review also briefly discusses their mechanisms of action, as they could provide new ideas for the further development of this field.

A Polylactide-Based Micellar Adjuvant Improves the Intensity and Quality of Immune Response

Micelles from amphiphilic polylactide-block-poly(N-acryloxysuccinimide-co-N-vinylpyrrolidone) (PLA-b-P(NAS-co-NVP)) block copolymers of 105 nm in size were characterized and evaluated in a vaccine context. The micelles were non-toxic in vitro (both in dendritic cells and HeLa cells). In vitro fluorescence experiments combined with in vivo fluorescence tomography imaging, through micelle loading with the DiR near infrared probe, suggested an efficient uptake of the micelles by the immune cells. The antigenic protein p24 of the HIV-1 was successfully coupled on the micelles using the reactive N-succinimidyl ester groups on the micelle corona, as shown by SDS-PAGE analyses. The antigenicity of the coupled antigen was preserved and even improved, as assessed by the immuno-enzymatic (ELISA) test. Then, the performances of the micelles in immunization were investigated and compared to different p24-coated PLA nanoparticles, as well as Alum and MF59 gold standards, following a standardized HIV-1 immunization protocol in mice. The humoral response intensity (IgG titers) was substantially similar between the PLA micelles and all other adjuvants over an extended time range (one year). More interestingly, this immune response induced by PLA micelles was qualitatively higher than the gold standards and PLA nanoparticles analogs, expressed through an increasing avidity index over time (>60% at day 365). Taken together, these results demonstrate the potential of such small-sized micellar systems for vaccine delivery.

Nanotechnology-empowered vaccine delivery for enhancing CD8+ T cells-mediated cellular immunity

After centuries of development, using vaccination to stimulate immunity has become an effective method for prevention and treatment of a variety of diseases including infective diseases and cancers. However, the tailor-made efficient delivery system for specific antigens is still urgently needed due to the low immunogenicity and stability of antigens, especially for vaccines to induce CD8⁺ T cells-mediated cellular immunity. Unlike B cells-mediated humoral immunity, CD8⁺ T cells-mediated cellular immunity mainly aims at the intracellular antigens from microorganism in virus-infected cells or genetic mutations in tumor cells. Therefore, the vaccines for stimulating CD8⁺ T cells-mediated cellular immunity should deliver the antigens efficiently into the cytoplasm of antigen presenting cells (APCs) to form major histocompatibility complex I (MHCI)-antigen complex through cross-presentation, followed by activating CD8⁺ T cells for immune protection and clearance. Importantly, nanotechnology has been emerged as a powerful tool to facilitate these multiple processes specifically, allowing not only enhanced antigen immunogenicity and stability but also APCs-targeted delivery and elevated cross-presentation. This review summarizes the process of CD8⁺ T cells-mediated cellular immunity induced by vaccines and the technical advantages of nanotechnology implementation in general, then provides an overview of the whole spectrum of nanocarriers studied so far and the recent development of delivery nanotechnology in vaccines against infectious diseases and cancer. Finally, we look forward to the future development of nanotechnology for the next generation of vaccines to induce CD8⁺ T cells-mediated cellular immunity.

Development of Effective Tumor Vaccine Strategies Based on Immune Response Cascade Reactions

To solve the problems of high toxicity and poor efficacy of existing tumor treatment methods, researchers have developed a variety of tumor immunotherapies. Among them, tumor vaccines activate antigen-presenting cells and T lymphocytes upstream of the cancer-immunity cycle are considered the most promising therapy to activate the immune system. Nanocarriers are considered the most promising tumor vaccine delivery vehicles, including polymer nanocarriers, lipid nanocarriers, inorganic nanocarriers, and biomimetic nanocarriers that have been developed for vaccine delivery. Based on the cascade reaction for tumor vaccines to exert their effects, this review summarizes the four key factors for the design and construction of nano-tumor vaccines. The composition and functional characteristics of the corresponding preferred nanocarriers are illustrated to provide a reference for the development of effective tumor vaccines. Finally, potential challenges and perspectives are illustrated in the hope of improving the efficacy of tumor vaccine immunotherapy and accelerating the clinical transformation of next-generation tumor vaccines.

Functionalized Particles Designed for Targeted Delivery

Pure bioactive compounds alone can only be exceptionally administered in medical treatment. Usually, drugs are produced as various forms of active compounds and auxiliary substances, combinations assuring the desired healing functions. One of the important drug forms is represented by a combination of active substances and particle-shaped polymer in the nano- or micrometer size range. The review describes recent progress in this field balanced with basic information. After a brief introduction, the paper presents a concise overview of polymers used as components of nano- and microparticle drug carriers. Thereafter, progress in direct synthesis of polymer particles with functional groups is discussed. A section is devoted to formation of particles by self-assembly of homo- and copolymer-bearing functional groups. Special attention is focused on modification of the primary functional groups introduced during particle preparation, including introduction of ligands promoting anchorage of particles onto the chosen living cell types by interactions with specific receptors present in cell membranes. Particular attention is focused on progress in methods suitable for preparation of particles loaded with bioactive substances. The review ends with a brief discussion of the still not answered questions and unsolved problems.

A pH/ROS cascade-responsive and self-accelerating drug release nanosystem for the targeted treatment of multi-drug-resistant colon cancer

The efficacy of chemotherapeutic agents for colon cancer treatment is limited by multidrug resistance (MDR) and insufficient intracellular release of the administered nanomedicine. To overcome these limitations, we constructed a pH/ROS cascade-responsive and self-accelerating drug release nanoparticle system (PLP-NPs) for the treatment of multidrug-resistant colon cancer. The PLP-NPs comprised a reactive oxygen species (ROS)-sensitive polymeric paclitaxel (PTX) prodrug (DEX-TK-PTX), a pH-sensitive poly(l-histidine) (PHis), and beta-lapachone (Lapa), a ROS-generating agent. We found that PLP-NPs could accumulate in tumor tissue through enhancement of the permeability and retention (EPR) effect, and were subsequently internalized by cancer cells via the endocytic pathway. Within the acidic endo-lysosomal environment, PHis protonation facilitated the escape of the PLP-NPs from the lysosome and release of Lapa. The released Lapa generated a large amount of ROS, consumed ATP, and downregulated P-glycoprotein (P-gp) production through the activity of NQO1, an enzyme that is specifically overexpressed in tumor cells. In addition, the generated ROS promoted the release of PTX from DEX-TK-PTX to kill cancer cells, while ATP depletion inhibited P-gp-mediated MDR. In vitro and in vivo experiments subsequently confirmed that PLP-NPs induced tumor-specific cytotoxicity and overcame the MDR of colon cancer. Our findings indicate that the use of the PLP-NPs system represents a promising strategy to counter MDR in the treatment of colon cancer.

Lymph Node Delivery Strategy Enables the Activation of Cytotoxic T Lymphocytes and Natural Killer Cells to Augment Cancer Immunotherapy

Lymph nodes are the main sites for immune activation and surveillance. Effective delivery of immunomodulators into lymph nodes to trigger antitumor immunity is essential for cancer treatment. Here, we propose a lymph node delivery strategy to modulate the immune response by activating cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells simultaneously. Novel pH/redox dual-sensitive micelles were prepared using poly(l-histidine)-poly(ethylene glycol) (PLH-PEG) as a skeleton, which can effectively deliver immunomodulators to the lymph nodes due to their suitable particle size. At 48 h after subcutaneous injection, the accumulation efficiency in lymph nodes increased 8.12-fold compared with the control group. Subsequently, Trp2/CpG-coloaded pH/redox dual-sensitive micelles (Trp2/CpG-NPs) acted on antigen-presenting cells, fully promoting CTL activation through dendritic cell antigen cross-presentation and macrophage repolarization. IL-15-loaded pH/redox dual-sensitive micelles (IL-15-NPs) were developed to activate the killing effect of NK cells by interacting with IL-15 receptors. In the tumor-bearing mice model, this lymph node delivery strategy showed significant antitumor efficiency and the tumor inhibition rate reached 93.76%. Meanwhile, the infiltration of CTLs and NK cells in tumor tissues increased, and the immunosuppressive microenvironment was relieved by the repolarization of macrophages from M2-type to M1-type. Overall, this study highlighted the potential of the lymph node delivery strategy for cancer immunotherapy.

Advances in Multiple Stimuli-Responsive Drug-Delivery Systems for Cancer Therapy

Nanomedicines afford unique advantages in therapeutic intervention against tumors. However, conventional nanomedicines have failed to achieve the desired effect against cancers because of the presence of complicated physiological fluids and the tumor microenvironment. Stimuli-responsive drug-delivery systems have emerged as potential tools for advanced treatment of cancers. Versatile nano-carriers co-triggered by multiple stimuli in different levels of organisms (eg, extracorporeal, tumor tissue, cell, subcellular organelles) have aroused widespread interest because they can overcome sequential physiological and pathological barriers to deliver diverse therapeutic “payloads” to the desired targets. Furthermore, multiple stimuli-responsive drug-delivery systems (MSR-DDSs) offer a good platform for co-delivery of agents and reversing multidrug resistance. This review affords a comprehensive overview on the “landscape” of MSR-DDSs against tumors, highlights the design strategies of MSR-DDSs in recent years, discusses the putative advantage of oncotherapy or the obstacles that so far have hindered the clinical translation of MSR-DDSs.

Therapeutic Vaccines for Cancer Immunotherapy

The rapid development of nanobiotechnology has enabled progress in therapeutic cancer vaccines. These vaccines stimulate the host innate immune response by tumor antigens followed by a cascading adaptive response against cancer. However, an improved antitumor immune response is still in high demand because of the unsatisfactory clinical performance of the vaccine in tumor inhibition and regression. To date, a complicated tumor immunosuppressive environment and suboptimal design are the main obstacles for therapeutic cancer vaccines. The optimization of tumor antigens, vaccine delivery pathways, and proper adjuvants for innate immune response initiation, along with reprogramming of the tumor immunosuppressive environment, is essential for therapeutic cancer vaccines in triggering an adequate antitumor immune response. In this review, we aim to review the challenges in and strategies for enhancing the efficacy of therapeutic vaccines. We start with the summary of the available tumor antigens and their properties and then the optimal strategies for vaccine delivery. Subsequently, the vaccine adjuvants focused on the intrinsic adjuvant properties of nanostructures are further discussed. Finally, we summarize the combination strategies with therapeutic cancer vaccines and discuss their positive impact in cancer immunity.

Development of Mannose-Modified Carboxylated Curdlan-Coated Liposomes for Antigen Presenting Cell Targeted Antigen Delivery

Specific delivery to antigen presenting cells (APC) and precise control of the intracellular fate of antigens are crucial to induce cellular immunity that directly and specifically attacks cancer cells. We previously achieved cytoplasmic delivery of antigen and activation of APC using carboxylated curdlan-modified liposomes, which led to the induction of cellular immunity in vivo. APCs express mannose receptors on their surface to recognize pathogen specifically and promote cross-presentation of antigen. In this study, mannose-residue was additionally introduced to carboxylated curdlan as a targeting moiety to APC for further improvement of polysaccharide-based antigen carriers. Mannose-modified curdlan derivatives were synthesized by the condensation between amino group-introduced mannose and carboxy group in pH-sensitive curdlan. Mannose residue-introduced carboxylated curdlan-modified liposomes showed higher pH-sensitivity than that of liposomes modified with conventional carboxylated curdlan. The introduction of mannose-residue to the liposomes induced aggregation in the presence of Concanavalin A, indicating that mannose residues were presented onto liposome surface. Mannose residue-introduced carboxylated curdlan-modified liposomes exhibited high and selective cellular association to APC. Furthermore, mannose residue-introduced carboxylated curdlan-modified liposomes promoted cross-presentation of antigen and induced strong antitumor effects on tumor-bearing mice. Therefore, these liposomes are promising as APC-specific antigen delivery systems for the induction of antigen-specific cellular immunity.

Dual pH/ROS-Responsive Nanoplatform with Deep Tumor Penetration and Self-Amplified Drug Release for Enhancing Tumor Chemotherapeutic Efficacy

Poor deep tumor penetration and incomplete intracellular drug release remain challenges for antitumor nanomedicine application in clinical settings. Herein, a nanomedicine (RLPA-NPs) is developed that can achieve prolonged blood circulation, deep tumor penetration, active-targeting of cancer cells, endosome/lysosome escape, and intracellular selectivity self-amplified drug release for effective drug delivery. The RLPA-NPs are constructed by encapsulation of a pH-sensitive polymer octadecylamine-poly(aspartate-1-(3-aminopropyl) imidazole) (OA-P(Asp-API)) and a ROS-generation agent, β-Lapachone (Lap), in micelles assembled by the tumor-penetration peptide internalizing RGD (iRGD)-modified ROS-responsive paclitaxel (PTX)-prodrug. iRGD could promote RLPA-NPs penetration into deep tumor tissue, and specific targeting to cancer cells. After internalization by cancer cells through receptor-mediated endocytosis, OA-P(Asp-API) can rapidly protonate in the endosome's acidic environment, resulting in RLPA-NPs escape from the endosome through the "proton sponge effect". At the same time, the RLPA-NPs micelle disassembles, releasing Lap and PTX-prodrug. Subsequently, the released Lap could generate ROS, consequently amplifying and accelerating PTX release to kill tumor cells. The in vitro and in vivo studies demonstrated that RLPA-NPs can significantly improve the therapeutic effect compared to control groups. Therefore, RLPA-NPs are a promising nanoplatform for overcoming multiple physiological and pathological barriers to enhance drug delivery.

A novel progress of drug delivery system for organelle targeting in tumour cells

At present, malignant tumours have become one of the most serious diseases that endanger human health. According to a survey on causes of death in Chinese population in early 1990s, the malignant tumours were the second leading cause of death. In the treatment of tumours, the ideal situation is that drugs should target and accumulate at tumour sites and destroy tumour cells specifically, without affecting normal cells and stem cells with regenerative capacity. This requires drugs to be specifically transported to the target organs, tissues, cells, and even specific organelles, like mitochondria, nuclei, lysosomes, endoplasmic reticulum (ER), and Golgi apparatus (GA). The nano drug delivery system can not only protect drugs from degradation but also facilitate functional modification and targeted drug delivery to the tumour site. This article mainly reviews the targeting of nano drug delivery systems to tumour cytoplasmic matrix, nucleus, mitochondria, ER, and lysosomes. Organelle-specific drug delivery system will be a major mean of targeting drug delivery with lower toxicity, less dosage and higher drug concentration in tumour cells.

The incorporation of cationic property and immunopotentiator in poly (lactic acid) microparticles promoted the immune response against chronic hepatitis B

Biodegradable microparticles (MPs) as vaccine adjuvants have sparked the passion of researchers in recent decades. However, it is still a huge challenge to develop an efficient vaccine delivery system to reverse chronic hepatitis B (CHB). Herein, we integrated a physiochemical merit and an immunopotentiator property in poly (lactic acid) (PLA) MPs and verified the therapeutic effect on CHB model mice. We prepared uniform MPs with insertion of cationic lipid didodecyldimethylammonium bromide (DDAB), which endowed a physiochemical merit for MPs. Such a DDAB-PLA (DP) group raised the recruitment of immune cells to the injection site along with the secretion of chemokines and pro-inflammatory cytokines, promoting the activation of antigen-presenting cells (APCs). Further combination of stimulator of interferon genes (STING) agonist 5,6-dimethylxanthenone-4-acetic acid (DMXAA) (DP-D) elevated 5.8-fold higher interferon regulatory factor 7 (IRF-7) expression compared to that for DP group. The DP group showed preferred lysosome escape advantage, which was in line with the DMXAA release behavior and the intracellular target of DMXAA. In addition, DP-D vaccine augmented the IFN-γ secreting splenocytes and motivated Th1-biased antibodies in a more efficient way than that for the DP group. In the CHB model, the MPs based vaccines achieved 50% HBsAg seroconversion rate, and HBcAg in the liver also got a reduction. DP-D produced higher amount of memory T/B cells to confer protection in a sustained manner. Present work thus provided a promising strategy, via integrating a fine-tuned physiochemical property and an immunopotentiator virtue in the MPs, which synergistically reinforced both humoral and cellular immune responses against CHB.

Multifunctional adenine-functionalized supramolecular micelles for highly selective and effective cancer chemotherapy

Adenine-functionalized supramolecular micelles are rapidly endocytosed by cancer cells and enable selective induction of tumor cell death, without harming normal cells.

Novel mitochondrial targeting charge-reversal polysaccharide hybrid shell/core nanoparticles for prolonged systemic circulation and antitumor drug delivery

Stability in systemic circulation, effective tumor accumulation, and the subsequent crucial subcellular targeting are significant elements that maximize the therapeutic efficacy of a drug. Accordingly, novel nanoparticles based on polysaccharides that simultaneously presented prolonged systemic circulation and mitochondrial-targeted drug release were synthesized. First, the mitochondrial-targeted polymer, 3,4-dihydroxyphenyl propionic acid-chitosan oligosaccharide-dithiodipropionic acid-berberine (DHPA-CDB), was synthesized, which was used to form self-assembled curcumin (Cur)-encapsulated cationic micelles (DHPA-CDB/Cur). Negatively charged oligomeric hyaluronic acid-3-carboxyphenylboronic acid (oHA-PBA), a ligand to sialic acid and CD44, was further added to the surface of the preformed DHPA-CDB/Cur core to shield the positive charges and to prolong blood persistence. oHA-PBA@DHPA-CDB/Cur formed a covalent polyplex of oHA-PBA and DHPA-CDB/Cur via the pH-responsive borate ester bond between PBA and DHPA. The mildly acidic tumor environment led to the degradation of borate ester bonds, thereby realizing the exposure of the cationic micelles and causing a charge reversal from -19.47 to +12.01 mV, to promote cell internalization and mitochondrial localization. Compared with micelles without the oHA-PBA modification, the prepared oHA-PBA@DHPA-CDB/Cur showed enhanced cytotoxicity to PANC-1 cells and greater cellular uptake via receptor-mediated endocytosis. oHA-PBA@DHPA-CDB/Cur was effectively targeted to the mitochondria, which triggered mitochondrial membrane depolarization. In mice xenografted with PANC-1 cells, compared with control mice, oHA-PBA@DHPA-CDB/Cur resulted in more effective tumor suppression and greater biosafety with preferential accumulation in the tumor tissue. Thus, the long-circulating oHA-PBA@DHPA-CDB/Cur, with mitochondrial targeting and tumor environment charge-reversal capabilities, was shown to be an excellent candidate for subcellular-specific drug delivery.

The Role of Nanovaccine in Cross-Presentation of Antigen-Presenting Cells for the Activation of CD8+ T Cell Responses

Explosive growth in nanotechnology has merged with vaccine development in the battle against diseases caused by bacterial or viral infections and malignant tumors. Due to physicochemical characteristics including size, viscosity, density and electrostatic properties, nanomaterials have been applied to various vaccination strategies. Nanovaccines, as they are called, have been the subject of many studies, including review papers from a material science point of view, although a mode of action based on a biological and immunological understanding has yet to emerge. In this review, we discuss nanovaccines in terms of CD8+ T cell responses, which are essential for antiviral and anticancer therapies. We focus mainly on the role and mechanism, with particular attention to the functional aspects, of nanovaccines in inducing cross-presentation, an unconventional type of antigen-presentation that activates CD8+ T cells upon administration of exogenous antigens, in dendritic cells followed by activation of antigen-specific CD8+ T cell responses. Two major intracellular mechanisms that nanovaccines harness for cross-presentation are described; one is endosomal swelling and rupture, and the other is membrane fusion. Both processes eventually allow exogenous vaccine antigens to be exported from phagosomes to the cytosol followed by loading on major histocompatibility complex class I, triggering clonal expansion of CD8+ T cells. Advancement of nanotechnology with an enhanced understanding of how nanovaccines work will contribute to the design of more effective and safer nanovaccines.

Recent advances in the synthetic and medicinal perspective of quinolones: A review

In the modern scenario, the quinolone scaffold has emerged as a very potent motif considering its clinical significance. Quinolones possess wide range of pharmacological activities such as anticancer, antibacterial, antifungal, antiprotozoal, antiviral, anti-inflammatory, carbonic anhydrase inhibitory and diuretic activity etc. The versatile synthetic approaches have been successfully applied and several of the resulted synthesized compounds exhibit fascinating biological activities in numerous fields. This has prompted to discover quinolone-based analogues among the researchers due to its great diversity in biological activities. In the past few years, various new, efficient and convenient synthetic approaches (including green chemistry and microwave-assisted synthesis) have been designed and developed to synthesize diverse quinolone-based scaffolds which represent a growing area of interest in academic and industry as well as to explore their biological activities. In this review, an attempt has been made by the authors to summarize (1) One of the most comprehensive listings of quinolone-based drugs or agents in the market or under various stages of clinical development; (2) Recent advances in the synthetic strategies for quinolone derivatives as well as their biological implications including insight of mechanistic studies. (3) Further, the biological data is correlated with structure-activity relationship studies to provide an insight into the rational design of more active agents.