Bacterial outer membrane vesicles-based therapeutic platform eradicates triple-negative breast tumor by combinational photodynamic/chemo-/immunotherapy

Bacterial outer membrane vesicles in the fight against cancer

ABSTRACT

Bacterial outer membrane vesicles (OMVs) are diminutive vesicles naturally released by Gram-negative bacteria. These vesicles possess distinctive characteristics that attract attention for their potential use in drug administration and immunotherapy in cancer treatment. Therapeutic medicines may be delivered via OMVs directly to the tumor sites, thereby minimizing exposure to healthy cells and lowering the risk of systemic toxicity. Furthermore, the activation of the immune system by OMVs has been demonstrated to facilitate the recognition and elimination of cancer cells, which makes them a desirable tool for immunotherapy. They can also be genetically modified to carry specific antigens, immunomodulatory compounds, and small interfering RNAs, enhancing the immune response to cancerous cells and silencing genes associated with disease progression. Combining OMVs with other cancer treatments like chemotherapy and radiation has shown promising synergistic effects. This review highlights the crucial role of bacterial OMVs in cancer, emphasizing their potential as vectors for novel cancer targeted therapies. As researchers delve deeper into the complexities of these vesicles and their interactions with tumors, there is a growing sense of optimism that this avenue of study will bring positive outcomes and renewed hope to cancer patients in the foreseeable future.

Nanomaterials Enhance Pyroptosis-Based Tumor Immunotherapy

Pyroptosis, a pro-inflammatory and lytic programmed cell death pathway, possesses great potential for antitumor immunotherapy. By releasing cellular contents and a large number of pro-inflammatory factors, tumor cell pyroptosis can promote dendritic cell maturation, increase the intratumoral infiltration of cytotoxic T cells and natural killer cells, and reduce the number of immunosuppressive cells within the tumor. However, the efficient induction of pyroptosis and prevention of damage to normal tissues or cells is an urgent concern to be addressed. Recently, a wide variety of nanoplatforms have been designed to precisely trigger pyroptosis and activate the antitumor immune responses. This review provides an update on the progress in nanotechnology for enhancing pyroptosis-based tumor immunotherapy. Nanomaterials have shown great advantages in triggering pyroptosis by delivering pyroptosis initiators to tumors, increasing oxidative stress in tumor cells, and inducing intracellular osmotic pressure changes or ion imbalances. In addition, the challenges and future perspectives in this field are proposed to advance the clinical translation of pyroptosis-inducing nanomedicines.

Bacterial outer membrane vesicle-cancer cell hybrid membrane-coated nanoparticles for sonodynamic therapy in the treatment of breast cancer bone metastasis

Breast cancer bone metastasis is a terminal-stage disease and is typically treated with radiotherapy and chemotherapy, which causes severe side effects and limited effectiveness. To improve this, Sonodynamic therapy may be a more safe and effective approach in the future. Bacterial outer membrane vesicles (OMV) have excellent immune-regulating properties, including modulating macrophage polarization, promoting DC cell maturation, and enhancing anti-tumor effects. Combining OMV with Sonodynamic therapy can result in synergetic anti-tumor effects. Therefore, we constructed multifunctional nanoparticles for treating breast cancer bone metastasis. We fused breast cancer cell membranes and bacterial outer membrane vesicles to form a hybrid membrane (HM) and then encapsulated IR780-loaded PLGA with HM to produce the nanoparticles, IR780@PLGA@HM, which had tumor targeting, immune regulating, and Sonodynamic abilities. Experiments showed that the IR780@PLGA@HM nanoparticles had good biocompatibility, effectively targeted to 4T1 tumors, promoted macrophage type I polarization and DC cells activation, strengthened anti-tumor inflammatory factors expression, and presented the ability to effectively kill tumors both in vitro and in vivo, which showed a promising therapeutic effect on breast cancer bone metastasis. Therefore, the nanoparticles we constructed provided a new strategy for effectively treating breast cancer bone metastasis.

Harnessing Bacterial Extracellular Vesicle Immune Effects for Cancer Therapy

There are a growing number of studies linking the composition of the human microbiome to disease states and treatment responses, especially in the context of cancer. This has raised significant interest in developing microbes and microbial products as cancer immunotherapeutics that mimic or recapitulate the beneficial effects of host-microbe interactions. Bacterial extracellular vesicles (bEVs) are nano-sized, membrane-bound particles secreted by essentially all bacteria species and contain a diverse bioactive cargo of the producing cell. They have a fundamental role in facilitating interactions among cells of the same species, different microbial species, and even with multicellular host organisms in the context of colonization (microbiome) and infection. The interaction of bEVs with the immune system has been studied extensively in the context of infection and suggests that bEV effects depend largely on the producing species. They thus provide functional diversity, while also being nonreplicative, having inherent cell-targeting qualities, and potentially overcoming natural barriers. These characteristics make them highly appealing for development as cancer immunotherapeutics. Both natively secreted and engineered bEVs are now being investigated for their application as immunotherapeutics, vaccines, drug delivery vehicles, and combinations of the above, with promising early results. This suggests that both the intrinsic immunomodulatory properties of bEVs and their ability to be modified could be harnessed for the development of next-generation microbe-inspired therapies. Nonetheless, there remain major outstanding questions regarding how the observed preclinical effectiveness will translate from murine models to primates, and humans in particular. Moreover, research into the pharmacology, toxicology, and mass manufacturing of this potential novel therapeutic platform is still at early stages. In this review, we highlight the breadth of bEV interactions with host cells, focusing on immunologic effects as the main mechanism of action of bEVs currently in preclinical development. We review the literature on ongoing efforts to develop natively secreted and engineered bEVs from a variety of bacterial species for cancer therapy and finally discuss efforts to overcome outstanding challenges that remain for clinical translation.

Bacterial extracellular vesicles: biotechnological perspective for enhanced productivity

Bacterial extracellular vesicles (BEVs) are non-replicative nanostructures released by Gram-negative and Gram-positive bacteria as a survival mechanism and inter- and intraspecific communication mechanism. Due to BEVs physical, biochemical, and biofunctional characteristics, there is interest in producing and using them in developing new therapeutics, vaccines, or delivery systems. However, BEV release is typically low, limiting their application. Here, we provide a biotechnological perspective to enhance BEV production, highlighting current strategies. The strategies include the production of hypervesiculating strains through gene modification, bacteria culture under stress conditions, and artificial vesicles production. We discussed the effect of these production strategies on BEVs types, morphology, composition, and activity. Furthermore, we summarized general aspects of BEV biogenesis, functional capabilities, and applications, framing their current importance and the need to produce them in abundance. This review will expand the knowledge about the range of strategies associated with BEV bioprocesses to increase their productivity and extend their application possibilities.

Engineering materials for pyroptosis induction in cancer treatment

Cancer remains a significant global health concern, necessitating the development of innovative therapeutic strategies. This research paper aims to investigate the role of pyroptosis induction in cancer treatment. Pyroptosis, a form of programmed cell death characterized by the release of pro-inflammatory cytokines and the formation of plasma membrane pores, has gained significant attention as a potential target for cancer therapy. The objective of this study is to provide a comprehensive overview of the current understanding of pyroptosis and its role in cancer treatment. The paper discusses the concept of pyroptosis and its relationship with other forms of cell death, such as apoptosis and necroptosis. It explores the role of pyroptosis in immune activation and its potential for combination therapy. The study also reviews the use of natural, biological, chemical, and multifunctional composite materials for pyroptosis induction in cancer cells. The molecular mechanisms underlying pyroptosis induction by these materials are discussed, along with their advantages and challenges in cancer treatment. The findings of this study highlight the potential of pyroptosis induction as a novel therapeutic strategy in cancer treatment and provide insights into the different materials and mechanisms involved in pyroptosis induction.

Salmonella enterica and outer membrane vesicles are current and future options for cancer treatment

Conventional cancer therapies have many limitations. In the last decade, it has been suggested that bacteria-mediated immunotherapy may circumvent the restrictions of traditional treatments. For example, Salmonella enterica is the most promising bacteria for treating cancer due to its intrinsic abilities, such as killing tumor cells, targeting, penetrating, and proliferating into the tumor. S. enterica has been genetically modified to ensure safety and increase its intrinsic antitumor efficacy. This bacterium has been used as a vector for delivering anticancer agents and as a combination therapy with chemotherapy, radiotherapy, or photothermic. Recent studies have reported the antitumor efficacy of outer membrane vesicles (OMVs) derived from S. enterica. OMVs are considered safer than attenuated bacteria and can stimulate the immune system as they comprise most of the immunogens found on the surface of their parent bacteria. Furthermore, OMVs can also be used as nanocarriers for antitumor agents. This review describes the advances in S. enterica as immunotherapy against cancer and the mechanisms by which Salmonella fights cancer. We also highlight the use of OMVs as immunotherapy and nanocarriers of anticancer agents. OMVs derived from S. enterica are innovative and promising strategies requiring further investigation.

Beyond Extracellular Vesicles: Hybrid Membrane Nanovesicles as Emerging Advanced Tools for Biomedical Applications

Extracellular vesicles (EVs), involved in essential physiological and pathological processes of the organism, have emerged as powerful tools for disease treatment owing to their unique natural biological characteristics and artificially acquired advantages. However, the limited targeting ability, insufficient production yield, and low drug-loading capability of natural simplex EVs have greatly hindered their development in clinical translation. Therefore, the establishment of multifunctional hybrid membrane nanovesicles (HMNVs) with favorable adaptability and flexibility has become the key to expanding the practical application of EVs. This timely review summarizes the current progress of HMNVs for biomedical applications. Different HMNVs preparation strategies including physical, chemical, and chimera approaches are first discussed. This review then individually describes the diverse types of HMNVs based on homologous or heterologous cell membrane substances, a fusion of cell membrane and liposome, as well as a fusion of cell membrane and bacterial membrane. Subsequently, a specific emphasis is placed on the highlight of biological applications of the HMNVs toward various diseases with representative examples. Finally, ongoing challenges and prospects of the currently developed HMNVs in clinical translational applications are briefly presented. This review will not only stimulate broad interest among researchers from diverse disciplines but also provide valuable insights for the development of promising nanoplatforms in precision medicine.

Bacteria and Bacterial Components as Natural Bio-Nanocarriers for Drug and Gene Delivery Systems in Cancer Therapy

Bacteria and bacterial components possess multifunctional properties, making them attractive natural bio-nanocarriers for cancer diagnosis and targeted treatment. The inherent tropic and motile nature of bacteria allows them to grow and colonize in hypoxic tumor microenvironments more readily than conventional therapeutic agents and other nanomedicines. However, concerns over biosafety, limited antitumor efficiency, and unclear tumor-targeting mechanisms have restricted the clinical translation and application of natural bio-nanocarriers based on bacteria and bacterial components. Fortunately, bacterial therapies combined with engineering strategies and nanotechnology may be able to reverse a number of challenges for bacterial/bacterial component-based cancer biotherapies. Meanwhile, the combined strategies tend to enhance the versatility of bionanoplasmic nanoplatforms to improve biosafety and inhibit tumorigenesis and metastasis. This review summarizes the advantages and challenges of bacteria and bacterial components in cancer therapy, outlines combinatorial strategies for nanocarriers and bacterial/bacterial components, and discusses their clinical applications.

Bacterial outer membrane vesicles as drug delivery carrier for photodynamic anticancer therapy

Photodynamic Therapy (PDT) is an effective tumor treatment strategy that not only induces photocytotoxicity to kill tumor cells directly but also activates the immune system in the body to generate tumor-specific immunity, preventing cancer metastasis and recurrence. However, some limitations of PDT limit the therapeutic efficacy in deep tumors. Previous studies have used different types of nanoparticles (NPs) as drug carriers of photosensitizers (PSs) to overcome the shortcomings of PDT and improve therapeutic efficacy. Among them, bacterial outer membrane vesicles (OMVs) have natural advantages as carriers for PS delivery. In addition to the targeted delivery of PSs into tumor cells, their unique immunogenicity helps them to serve as immune adjuvants to enhance the PDT-induced immune effect, providing new ideas for photodynamic anticancer therapy. Therefore, in this review, we will introduce the biogenesis and anticancer functions of OMVs and the research on them as drug delivery carriers in PDT. Finally, we also discuss the challenges and prospects of OMVs as a versatile drug delivery carrier for photodynamic anticancer therapy.

Advances in anti-tumor based on various anaerobic bacteria and their derivatives as drug vehicles

Cancer therapies, such as chemotherapy and radiotherapy, are often unsatisfactory due to several limitations, including drug resistance, inability to cross biological barriers, and toxic side effects on the body. These drawbacks underscore the need for alternative treatments that can overcome these challenges and provide more effective and safer options for cancer patients. In recent years, the use of live bacteria, engineered bacteria, or bacterial derivatives to deliver antitumor drugs to specific tumor sites for controlled release has emerged as a promising therapeutic tool. This approach offers several advantages over traditional cancer therapies, including targeted drug delivery and reduced toxicity to healthy tissues. Ongoing research in this field holds great potential for further developing more efficient and personalized cancer therapies, such as E. coli, Salmonella, Listeria, and bacterial derivatives like outer membrane vesicles (OMVs), which can serve as vehicles for drugs, therapeutic proteins, or antigens. In this review, we describe the advances, challenges, and future directions of research on using live bacteria or OMVs as carriers or components derived from bacteria of delivery systems for cancer therapy.

Anti-EGFR bioengineered bacterial outer membrane vesicles as targeted immunotherapy candidate in triple-negative breast tumor murine model

Cancer immunotherapy employing checkpoint inhibitors holds great promise across diverse cancers; nonetheless, a substantial proportion of patients (ranging from 55 to 87%) remain unresponsive to this treatment. To amplify therapeutic efficiency, we propose a synergistic therapeutic strategy that entails the deployment of targeted nano-sized particles carrying Toll-like receptor (TLR) agonists to the tumor site. This innovative approach seeks to activate intratumoral antigen-presenting cells using bioengineered outer membrane vesicles (OMVs) derived from gram-negative bacteria. These OMVs possess inherent attributes of surface-exposed immune stimulators and TLR-activating components, rendering them intriguing candidates for investigation. These OMVs were meticulously designed to selectively target cancer cells exhibiting an overexpression of epidermal growth factor receptor (EGFR). To gauge the precision of this targeting, the conducted affinity-based assays aimed at determining the equilibrium dissociation constant of the single-chain variable fragment employed for this purpose. In vitro experiments confirmed the OMVs' proficiency in adhering to EGFR-overexpressed cancer cells. Moreover, the evaluation extended to an in vivo context, where the therapeutic effect of nanovesicles was appraised within the tumor microenvironment of the triple-negative breast cancer mouse model. Notably, both intraperitoneal and intratumoral administrations of nanovesicles exhibited the ability to activate natural killer cells and skew M2 macrophage towards an M1 phenotype. The combined scrutiny of in vitro and in vivo findings underscores the potential efficiency of OMVs as a promising strategy for future anti-tumor endeavors.

Bacterial outer membrane vesicles in cancer: Biogenesis, pathogenesis, and clinical application

Outer membrane vesicles (OMVs) are spherical, nano-sized particles of bilayer lipid structure secreted by Gram-negative bacteria. They contain a series of cargos from bacteria and are important messengers for communication between bacteria and their environment. OMVs play multiple roles in bacterial survival and adaptation and can affect host physiological functions and disease development by acting on host cell membranes and altering host cell signaling pathways. This paper summarizes the mechanisms of OMV genesis and the multiple roles of OMVs in the tumor microenvironment. Also, this paper discusses the prospects of OMVs for a wide range of applications in drug delivery, tumor diagnosis, and therapy.

Macrophage-reprogramming upconverting nanoparticles for enhanced TAM-mediated antitumor therapy of hypoxic breast cancer

In an attempt to achieve antitumor effects by switching the phenotype of macrophages from the tumor-promoting M2 type to the tumor-suppressing M1 type, we fabricated mannose-decorated/macrophage membrane-coated, silica-layered NaErF4@NaLuF4 upconverting nanoparticles (UCNPs) co-doped with perfluorocarbon (PFC)/chlorin e6 (Ce6) and loaded with paclitaxel (PTX) (UCNP@mSiO2-PFC/Ce6@RAW-Man/PTX: ∼61 nm; -11.6 mV). These nanoparticles were designed to have two major functionalities, (i) efficient singlet oxygen generation aided by an oxygen supply and (ii) good targeting to tumor-associated macrophage (TAMs) (M2-type), to induce polarization to M1 type macrophages that release proinflammatory cytokines and suppress breast cancers. The primary UCNPs consisted of lanthanide elements (erbium and lutetium) in a core@shell structure, and they facilely emitted 660 nm light in response to a deep-penetrating 808 nm near-infrared laser. Moreover, the UCNPs@mSiO2-PFC/Ce6@RAW-Man/PTX were able to release O2 and generate 1O2 because of the co-doped PFC/Ce6 and upconversion. Our nanocarriers' excellent uptake to RAW 264.7 macrophage cells (M2 type) and efficient M1-type polarization activity were clearly demonstrated using qRT-PCR and immunofluorescence-based confocal laser scanning microscopy. Our nanocarriers displayed significant cytotoxicity to 4T1 cells in 2D culture and 3D co-culture systems of 4T1/RAW 264.7 cells. More importantly, UCNPs@mSiO2-PFC/Ce6@RAW-Man/PTX (+808 nm laser) noticeably suppressed tumor growth in 4T1-xenografted mice, compared with the other treatment groups (332.4 vs. 709.5-1185.5 mm3). We attribute this antitumor efficacy to the prominent M1-type macrophage polarization caused by our nanocarriers through efficient ROS/O2 generation and targeting of M2-type TAMs via mannose ligands on coated macrophage-membrane.

Biomimetic Cell-Derived Nanoparticles: Emerging Platforms for Cancer Immunotherapy

Cancer immunotherapy can significantly prevent tumor growth and metastasis by activating the autoimmune system without destroying normal cells. Although cancer immunotherapy has made some achievements in clinical cancer treatment, it is still restricted by systemic immunotoxicity, immune cell dysfunction, cancer heterogeneity, and the immunosuppressive tumor microenvironment (ITME). Biomimetic cell-derived nanoparticles are attracting considerable interest due to their better biocompatibility and lower immunogenicity. Moreover, biomimetic cell-derived nanoparticles can achieve different preferred biological effects due to their inherent abundant source cell-relevant functions. This review summarizes the latest developments in biomimetic cell-derived nanoparticles for cancer immunotherapy, discusses the applications of each biomimetic system in cancer immunotherapy, and analyzes the challenges for clinical transformation.

Hybrid biointerface engineering nanoplatform for dual-targeted tumor hypoxia relief and enhanced photodynamic therapy

The clinical application of photodynamic therapy (PDT) is limited by the lack of tumor selectivity of photosensitizer (PS) and the hypoxic tumor microenvironment (TME). To address these limitations of PDT, we developed a hybrid engineered biointerface nanoplatform that integrated anti-epidermal growth factor receptor (EGFR)-aptamer (EApt)-modified liposomes with tumor cell membranes (TMs) to create M/L-EApt. M/L-EApt exhibited enhanced stability and significant dual-targeting ability, enabling selectively accumulate in hypoxic tumor regions after systemic infusion. PHI@M/L-EApt, formed by M/L-EApt loaded with an oxygen carrier perfluorotributylamine (PFTBA) and IR780 (a PS), effectively promoted the therapeutic performance of PDT by reversing the hypoxic TME and increasing the accumulation of IR780 at the tumor sites, resulting in a robust anti-tumor efficacy. In vivo results showed that PHI@M/L-EApt treatment effectively suppressed the growth of triple-negative breast tumors in mice. Our findings demonstrated the synergistic effect of oxygen supply and PDT on tumor treatment using PHI@M/L-EApt. This study presented a biomimetic interface engineering strategy and dual-targeted hybrid nanoplatform for relieving hypoxic TME and potentially facilitating the clinical application of PDT.

Bacterial extracellular vesicles and their interplay with the immune system

The mammalian intestinal tract harbors trillions of microorganisms confined within this space by mucosal barriers. Despite these barriers, bacterial components may still be found elsewhere in the body, even in healthy subjects. Bacteria can release small lipid-bound particles, also named bacterial extracellular vesicles (bEV). While bacteria themselves cannot normally penetrate the mucosal defense, bEVs may infiltrate the barrier and disseminate throughout the body. The extremely diverse cargo that bEVs can carry, depending on their parent species, strain, and growth conditions, grant them an equally broad potential to interact with host cells and influence immune functions. Herein, we review the current knowledge of processes underlying the uptake of bEVs by mammalian cells, and their effect on the immune system. Furthermore, we discuss how bEVs could be targeted and manipulated for diverse therapeutic purposes.

Functionalization of OMVs for Biocatalytic Applications

Outer membrane vesicles (OMVs) are miniature versions of gram-negative bacteria that contain almost the same content as their parent cells, particularly in terms of membrane composition. Using OMVs as biocatalysts is a promising approach due to their potential benefits, including their ability to be handled similarly to bacteria while lacking potentially pathogenic organisms. To employ OMVs as biocatalysts, they must be functionalized with immobilized enzymes to the OMV platform. Various enzyme immobilization techniques are available, including surface display and encapsulation, each with advantages and disadvantages depending on the objectives. This review provides a concise yet comprehensive overview of these immobilization techniques and their applications in utilizing OMVs as biocatalysts. Specifically, we discuss the use of OMVs in catalyzing the conversion of chemical compounds, their role in polymer degradation, and their performance in bioremediation.

Bacterial Membrane Vesicles as Smart Drug Delivery and Carrier Systems: A New Nanosystems Tool for Current Anticancer and Antimicrobial Therapy

Bacterial membrane vesicles (BMVs) are known to be critical communication tools in several pathophysiological processes between bacteria and host cells. Given this situation, BMVs for transporting and delivering exogenous therapeutic cargoes have been inspiring as promising platforms for developing smart drug delivery systems (SDDSs). In the first section of this review paper, starting with an introduction to pharmaceutical technology and nanotechnology, we delve into the design and classification of SDDSs. We discuss the characteristics of BMVs including their size, shape, charge, effective production and purification techniques, and the different methods used for cargo loading and drug encapsulation. We also shed light on the drug release mechanism, the design of BMVs as smart carriers, and recent remarkable findings on the potential of BMVs for anticancer and antimicrobial therapy. Furthermore, this review covers the safety of BMVs and the challenges that need to be overcome for clinical use. Finally, we discuss the recent advancements and prospects for BMVs as SDDSs and highlight their potential in revolutionizing the fields of nanomedicine and drug delivery. In conclusion, this review paper aims to provide a comprehensive overview of the state-of-the-art field of BMVs as SDDSs, encompassing their design, composition, fabrication, purification, and characterization, as well as the various strategies used for targeted delivery. Considering this information, the aim of this review is to provide researchers in the field with a comprehensive understanding of the current state of BMVs as SDDSs, enabling them to identify critical gaps and formulate new hypotheses to accelerate the progress of the field.

Targeting pyroptosis in breast cancer: biological functions and therapeutic potentials on It

Pyroptosis is a lytic and inflammatory type of programmed cell death that is mediated by Gasdermin proteins (GSDMs). Attractively, recent evidence indicates that pyroptosis involves in the development of tumors and can serve as a new strategy for cancer treatment. Here, we present a basic knowledge of pyroptosis, and an overview of the expression patterns and roles of GSDMs in breast cancer. In addition, we further summarize the available evidence of pyroptosis in breast cancer progression and give insight into the clinical potential of applying pyroptosis in anticancer strategies for breast cancer. This review will deepen our understanding of the relationship between pyroptosis and breast cancer, and provide a novel potential therapeutic avenue for breast cancer.

Bioengineered Bacterial Membrane Vesicles with Multifunctional Nanoparticles as a Versatile Platform for Cancer Immunotherapy

Inducing immunogenic cell death (ICD) is a critical strategy for enhancing cancer immunotherapy. However, inefficient and risky ICD inducers along with a tumor hypoxia microenvironment seriously limit the immunotherapy efficacy. Non-specific delivery is also responsible for this inefficiency. In this work, we report a drug-free bacteria-derived outer membrane vesicle (OMV)-functionalized Fe₃O₄-MnO₂ (FMO) nanoplatform that realized neutrophil-mediated targeted delivery and photothermally enhanced cancer immunotherapy. In this system, modification of OMVs derived from Escherichia coli enhanced the accumulation of FMO NPs at the tumor tissue through neutrophil-mediated targeted delivery. The FMO NPs underwent reactive decomposition in the tumor site, generating manganese and iron ions that induced ICD and O₂ that regulated the tumor hypoxia environment. Moreover, OMVs are rich in pathogen-associated pattern molecules that can overcome the tumor immunosuppressive microenvironment and effectively activate immune cells, thereby enhancing specific immune responses. Photothermal therapy (PTT) caused by MnO₂ and Fe₃O₄ can not only indirectly stimulate systemic immunity by directly destroying tumor cells but also promote the enrichment of neutrophil-equipped nanoparticles by enhancing the inflammatory response at the tumor site. Finally, the proposed multi-modal treatment system with targeted delivery capability realized effective tumor immunotherapy to prevent tumor growth and recurrence.

Nanomedicine-Enabled/Augmented Cell Pyroptosis for Efficient Tumor Nanotherapy

The terrible morbidity and mortality of malignant tumors urgently require innovative therapeutics, especially for apoptosis-resistant tumors. Pyroptosis, a pro-inflammatory form of programmed cell death (PCD), is featured with pore formation in plasma membrane, cell swelling with giant bubbles, and leakage of cytoplasmic pro-inflammatory cytokines, which can remodel the tumor immune microenvironment by stimulating a "cold" tumor microenvironment to be an immunogenic "hot" tumor microenvironment, and consequently augment the therapeutic efficiency of malignant tumors. Benefiting from current advances in nanotechnology, nanomedicine is extensively applied to potentiate, enable, and augment pyroptosis for enhancing cancer-therapeutic efficacy and specificity. This review provides a concentrated summary and discussion of the most recent progress achieved in this emerging field, highlighting the nanomedicine-enabled/augmented specific pyroptosis strategy for favoring the construction of next-generation nanomedicines to efficiently induce PCD. It is highly expected that the further clinical translation of nanomedicine can be accelerated by inducing pyroptotic cell death based on bioactive nanomedicines.

Renal Proximal Tubular Cells: A New Site for Targeted Delivery Therapy of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a major complication of diabetes mellitus (DM) and the leading cause of end-stage kidney disease (ESKD) worldwide. A significant number of drugs have been clinically investigated for the treatment of DKD. However, a large proportion of patients still develop end-stage kidney disease unstoppably. As a result, new effective therapies are urgently needed to slow down the progression of DKD. Recently, there is increasing evidence that targeted drug delivery strategies such as large molecule carriers, small molecule prodrugs, and nanoparticles can improve drug efficacy and reduce adverse side effects. There is no doubt that targeted drug delivery strategies have epoch-making significance and great application prospects for the treatment of DKD. In addition, the proximal tubule plays a very critical role in the progression of DKD. Consequently, the purpose of this paper is to summarize the current understanding of proximal tubule cell-targeted therapy, screen for optimal targeting strategies, and find new therapeutic approaches for the treatment of DKD.