Hybrid Vesicles Based on Autologous Tumor Cell Membrane and Bacterial Outer Membrane To Enhance Innate Immune Response and Personalized Tumor Immunotherapy

Bacteria-based bioactive materials for cancer imaging and therapy

Owing to the unique biological functions, bacteria as biological materials have been widely used in biomedical field. With advances in biotechnology and nanotechnology, various bacteria-based bioactive materials were developed for cancer imaging and therapy. In this review, different types of bacteria-based bioactive materials and their construction strategies were summarized. The advantages and property-function relationship of bacteria-based bioactive materials were described. Representative researches of bacteria-based bioactive materials in cancer imaging and therapy were illustrated, revealing general ideas for their construction. Also, limitation and challenges of bacteria-based bioactive materials in cancer research were discussed.

Bacterial Membrane Mimetics: From Biosensing to Disease Prevention and Treatment

Plasma membrane mimetics can potentially play a vital role in drug discovery and immunotherapy owing to the versatility to assemble facilely cellular membranes on surfaces and/or nanoparticles, allowing for direct assessment of drug/membrane interactions. Recently, bacterial membranes (BMs) have found widespread applications in biomedical research as antibiotic resistance is on the rise, and bacteria-associated infections have become one of the major causes of death worldwide. Over the last decade, BM research has greatly benefited from parallel advancements in nanotechnology and bioelectronics, resulting in multifaceted systems for a variety of sensing and drug discovery applications. As such, BMs coated on electroactive surfaces are a particularly promising label-free platform to investigate interfacial phenomena, as well as interactions with drugs at the first point of contact: the bacterial membrane. Another common approach suggests the use of lipid-coated nanoparticles as a drug carrier system for therapies for infectious diseases and cancer. Herein, we discuss emerging platforms that make use of BMs for biosensing, bioimaging, drug delivery/discovery, and immunotherapy, focusing on bacterial infections and cancer. Further, we detail the synthesis and characteristics of BMs, followed by various models for utilizing them in biomedical applications. The key research areas required to augment the characteristics of bacterial membranes to facilitate wider applicability are also touched upon. Overall, this review provides an interdisciplinary approach to exploit the potential of BMs and current emerging technologies to generate novel solutions to unmet clinical needs.

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.

Harnessing Engineered Immune Cells and Bacteria as Drug Carriers for Cancer Immunotherapy

Immunotherapy continues to be in the spotlight of oncology therapy research in the past few years and has been proven to be a promising option to modulate one's innate and adaptive immune systems for cancer treatment. However, the poor delivery efficiency of immune agents, potential off-target toxicity, and nonimmunogenic tumors significantly limit its effectiveness and extensive application. Recently, emerging biomaterial-based drug carriers, including but not limited to immune cells and bacteria, are expected to be potential candidates to break the dilemma of immunotherapy, with their excellent natures of intrinsic tumor tropism and immunomodulatory activity. More than that, the tiny vesicles and physiological components derived from them have similar functions with their source cells due to the inheritance of various surface signal molecules and proteins. Herein, we presented representative examples about the latest advances of biomaterial-based delivery systems employed in cancer immunotherapy, including immune cells, bacteria, and their derivatives. Simultaneously, opportunities and challenges of immune cells and bacteria-based carriers are discussed to provide reference for their future application in cancer immunotherapy.

Nanomedicine embraces cancer radio-immunotherapy: mechanism, design, recent advances, and clinical translation

Cancer radio-immunotherapy, integrating external/internal radiation therapy with immuno-oncology treatments, emerges in the current management of cancer. A growing number of pre-clinical studies and clinical trials have recently validated the synergistic antitumor effect of radio-immunotherapy, far beyond the "abscopal effect", but it suffers from a low response rate and toxicity issues. To this end, nanomedicines with an optimized design have been introduced to improve cancer radio-immunotherapy. Specifically, these nanomedicines are elegantly prepared by incorporating tumor antigens, immuno- or radio-regulators, or biomarker-specific imaging agents into the corresponding optimized nanoformulations. Moreover, they contribute to inducing various biological effects, such as generating in situ vaccination, promoting immunogenic cell death, overcoming radiation resistance, reversing immunosuppression, as well as pre-stratifying patients and assessing therapeutic response or therapy-induced toxicity. Overall, this review aims to provide a comprehensive landscape of nanomedicine-assisted radio-immunotherapy. The underlying working principles and the corresponding design strategies for these nanomedicines are elaborated by following the concept of "from bench to clinic". Their state-of-the-art applications, concerns over their clinical translation, along with perspectives are covered.

Targeting inorganic nanoparticles to tumors using biological membrane-coated technology

Inorganic nanoparticles have extensively revolutionized the effectiveness of cancer therapeutics due to their distinct physicochemical properties. However, the therapeutic efficiency of inorganic nanoparticles is greatly hampered by the complex tumor microenvironment, patient heterogeneity, and systemic nonspecific toxicity. The biomimetic technology based on biological membranes (cell- or bacteria-derived membranes) is a promising strategy to confer unique characteristics to inorganic nanoparticles, such as superior biocompatibility, prolonged circulation time, immunogenicity, homologous tumor targeting, and flexible engineering approaches on the surface, resulting in the enhanced therapeutic efficacy of inorganic nanoparticles against cancer. Therefore, a greater push toward developing biomimetic-based nanotechnology could increase the specificity and potency of inorganic nanoparticles for effective cancer treatment. In this review, we summarize the recent advances in biological membrane-coated inorganic nanoparticles in cancer precise therapy and highlight the different types of engineered approaches, applications, mechanisms, and future perspectives. The surface engineering of biological membrane can greatly enhance their targeting, intelligence, and functionality, thereby realizing stronger tumor therapy effects. Further advances in materials science, biomedicine, and oncology can facilitate the clinical translation of biological membrane-coated inorganic nanoparticles.

Systematic design of cell membrane coating to improve tumor targeting of nanoparticles

Cell membrane (CM) coating technology is increasingly being applied in nanomedicine, but the entire coating procedure including adsorption, rupture, and fusion is not completely understood. Previously, we showed that the majority of biomimetic nanoparticles (NPs) were only partially coated, but the mechanism underlying this partial coating remains unclear, which hinders the further improvement of the coating technique. Here, we show that partial coating is an intermediate state due to the adsorption of CM fragments or CM vesicles, the latter of which could eventually be ruptured under external force. Such partial coating is difficult to self-repair to achieve full coating due to the limited membrane fluidity. Building on our understanding of the detailed coating process, we develop a general approach for fixing the partial CM coating: external phospholipid is introduced as a helper to increase CM fluidity, promoting the final fusion of lipid patches. The NPs coated with this approach have a high ratio of full coating (~23%) and exhibit enhanced tumor targeting ability in comparison to the NPs coated traditionally (full coating ratio of ~6%). Our results provide a mechanistic basis for fixing partial CM coating towards enhancing tumor accumulation.

Recent Advances in Bacteria-Based Cancer Treatment

Simple Summary

Cancer refers to a disease involving abnormal cells that proliferate uncontrollably and can invade normal body tissue. It was estimated that at least 9 million patients are killed by cancer annually. Recent studies have demonstrated that bacteria play a significant role in cancer treatment and prevention. Owing to its unique mechanism of abundant pathogen-associated molecular patterns in antitumor immune responses and preferentially accumulating and proliferating within tumors, bacteria-based cancer immunotherapy has recently attracted wide attention. We aim to illustrate that naïve bacteria and their components can serve as robust theranostic agents for cancer eradication. In addition, we summarize the recent advances in efficient antitumor treatments by genetically engineering bacteria and bacteria-based nanoparticles. Further, possible future perspectives in bacteria-based cancer immunotherapy are also inspected.

Abstract

Owing to its unique mechanism of abundant pathogen-associated molecular patterns in antitumor immune responses, bacteria-based cancer immunotherapy has recently attracted wide attention. Compared to traditional cancer treatments such as surgery, chemotherapy, radiotherapy, and phototherapy, bacteria-based cancer immunotherapy exhibits the versatile capabilities for suppressing cancer thanks to its preferentially accumulating and proliferating within tumors. In particular, bacteria have demonstrated their anticancer effect through the toxins, and other active components from the cell membrane, cell wall, and dormant spores. More importantly, the design of engineering bacteria with detoxification and specificity is essential for the efficacy of bacteria-based cancer therapeutics. Meanwhile, bacteria can deliver the cytokines, antibody, and other anticancer theranostic nanoparticles to tumor microenvironments by regulating the expression of the bacterial genes or chemical and physical loading. In this review, we illustrate that naïve bacteria and their components can serve as robust theranostic agents for cancer eradication. In addition, we summarize the recent advances in efficient antitumor treatments by genetically engineering bacteria and bacteria-based nanoparticles. Further, possible future perspectives in bacteria-based cancer immunotherapy are also inspected.

Personalized Targeted Therapeutic Strategies against Oral Squamous Cell Carcinoma. An Evidence-Based Review of Literature

Oral squamous cell carcinoma (OSCC) is the most common type of malignant tumor in the head and neck, with a poor prognosis mainly due to recurrence and metastasis. Classical treatment modalities for OSCC like surgery and radiotherapy have difficulties in dealing with metastatic tumors, and together with chemotherapy, they have major problems related to non-specific cell death. Molecular targeted therapies offer solutions to these problems through not only potentially maximizing the anticancer efficacy but also minimizing the treatment-related toxicity. Among them, the receptor-mediated targeted delivery of anticancer therapeutics remains the most promising one. As OSCC exhibits a heterogeneous nature, selecting the appropriate receptors for targeting is the prerequisite. Hence, we reviewed the OSCC-associated receptors previously used in targeted therapy, focused on their biochemical characteristics and expression patterns, and discussed the application potential in personalized targeted therapy of OSCC. We hope that a better comprehension of this subject will help to provide the fundamental information for OSCC personalized therapeutic planning.

Development and application of bionic systems consisting of tumor-cell membranes

Malignant tumors pose a serious threat to human health but during the past decade, great progress has been made in the treatment of tumors. The tumor-cell membrane is well constructed and can be used to solve problems in tumor therapy. Tumor-cell membranes exhibit not only high biocompatibility due to their homology but also enhanced therapeutic effects when combined with nanotechnology. Meanwhile, nanomaterials show high selectivity, sensitivity, and clinical transformation potential. Enhanced immunotherapy or tumor vaccines have potential clinical application because of tumor-membrane surface-specific antigens. Several studies have confirmed the feasibility and advantages of using tumor-cell membrane-incorporated nanosystems for tumor therapy. Considering all this, we focus in this review on the application of tumor-cell-membrane bionic platforms and, in the summary, provide ideas for new scientific developments.

Research progress of tumor-derived extracellular vesicles in the treatment of malignant pleural effusion

Vesicles, also known as "microparticles", are vesicle-like structures that are released outside the cell in a "sprouting" manner when the cytoskeleton is changed during cell activation or apoptosis, with a diameter of about 100-1000 nm, and are carriers of material information exchange between cells. Tumor-derived extracellular vesicles can effectively deliver drugs to the nucleus of tumor stem cells, thus effectively killing them without toxic side effects. The underlying mechanism involves the soft nature of tumor stem cells that allows better uptake of vesicles, and the entry of drug-carrying vesicles into lysosomes and facilitation of lysosomal movement toward the nucleus to deliver drugs to the nucleus. Drug-loaded vesicles have unique advantages, such as low immunogenicity, homing targeting ability, and the ability to break through the physiological barrier to tumor therapy. Tumor-derived drug-delivery vesicles have entered clinical trials for the treatment of malignant pleural effusions. In this review, we summarized the progress of basic and clinical research on tumor cell-derived drug-loaded vesicles for the treatment of malignant pleural effusion in recent years.

Tumor-Derived Membrane Vesicles: A Promising Tool for Personalized Immunotherapy

Tumor-derived membrane vesicles (TDMVs) are non-invasive, chemotactic, easily obtained characteristics and contain various tumor-borne substances, such as nucleic acid and proteins. The unique properties of tumor cells and membranes make them widely used in drug loading, membrane fusion and vaccines. In particular, personalized vectors prepared using the editable properties of cells can help in the design of personalized vaccines. This review focuses on recent research on TDMV technology and its application in personalized immunotherapy. We elucidate the strengths and challenges of TDMVs to promote their application from theory to clinical practice.

Cell Membrane-Derived Vesicle: A Novel Vehicle for Cancer Immunotherapy

As nano-sized materials prepared by isolating, disrupting and extruding cell membranes, cellular vesicles are emerging as a novel vehicle for immunotherapeutic drugs to activate antitumor immunity. Cell membrane-derived vesicles inherit the surface characteristics and functional properties of parental cells, thus having superior biocompatibility, low immunogenicity and long circulation. Moreover, the potent antitumor effect of cellular vesicles can be achieved through surface modification, genetic engineering, hybridization, drug encapsulation, and exogenous stimulation. The capacity of cellular vesicles to combine drugs of different compositions and functions in physical space provides a promising vehicle for combinational immunotherapy of cancer. In this review, the latest advances in cellular vesicles as vehicles for combinational cancer immunotherapy are systematically summarized with focuses on manufacturing processes, cell sources, therapeutic strategies and applications, providing an insight into the potential and existing challenges of using cellular vesicles for cancer immunotherapy.

Engineered bacterial membrane vesicles are promising carriers for vaccine design and tumor immunotherapy

Bacterial membrane vesicles (BMVs) have emerged as novel and promising platforms for the development of vaccines and immunotherapeutic strategies against infectious and noninfectious diseases. The rich microbe-associated molecular patterns (MAMPs) and nanoscale membrane vesicle structure of BMVs make them highly immunogenic. In addition, BMVs can be endowed with more functions via genetic and chemical modifications. This article reviews the immunological characteristics and effects of BMVs, techniques for BMV production and modification, and the applications of BMVs as vaccines or vaccine carriers. In summary, given their versatile characteristics and immunomodulatory properties, BMVs can be used for clinical vaccine or immunotherapy applications.

Long circulation and tumor-targeting biomimetic nanoparticles for efficient chemo/photothermal synergistic therapy

Photothermal therapy combined with chemotherapy based on nanomedicine has been considered a promising strategy for improving therapeutic efficacy in a tumor. However, nanomedicine can be easily cleared by the immune system without specific surface engineering modifications, thus affecting the ultimate efficacy. Herein, multifunctional biomimetic nanoparticles (Bio-RBCm@PDA@MSN-DOX) with enhanced long circulation and targeting ability are constructed by coating large pore-sized mesoporous silica (MSN) with polydopamine (PDA) layers in a biotin modified red blood cell membrane (Bio-RBCm) for efficient chemo/photothermal synergistic therapy. It is demonstrated that Bio-RBCm@PDA@MSN-DOX presents high photothermal conversion efficiency (40.17%) and enhanced capability to accelerate the release of the anticancer drug (doxorubicin, DOX), thus showing a good synergistic therapeutic effect in cell experiments. More importantly, with the assistance of the biotin and RBC membrane, Bio-RBCm@PDA@MSN-DOX can successfully evade immune clearance and effectively target transport to HeLa tumor sites, finally accomplishing up to 98.95% tumor inhibition with negligible side effects to normal tissues. This multilayer structure presents a valuable model for future therapeutic applications with safe and effective tumor chemotherapy and photothermal therapy.

Application of lipid nanovesicle drug delivery system in cancer immunotherapy

Immunotherapy has gradually emerged as the most promising anticancer therapy. In addition to conventional anti-PD-1/PD-L1 therapy, anti-CTLA-4 therapy, CAR-T therapy, etc., immunotherapy can also be induced by stimulating the maturation of immune cells or inhibiting negative immune cells, regulating the tumor immune microenvironment and cancer vaccines. Lipid nanovesicle drug delivery system includes liposomes, cell membrane vesicles, bacterial outer membrane vesicles, extracellular vesicles and hybrid vesicles. Lipid nanovesicles can be used as functional vesicles for cancer immunotherapy, and can also be used as drug carriers to deliver immunotherapy drugs to the tumor site for cancer immunotherapy. Here, we review recent advances in five kinds of lipid nanovesicles in cancer immunotherapy and assess the clinical application prospects of various lipid nanovesicles, hoping to provide valuable information for clinical translation in the future.

Latest Advances in Biomimetic Cell Membrane-Coated and Membrane-Derived Nanovectors for Biomedical Applications

In the last decades, many nanovectors were developed for different diagnostic or therapeutic purposes. However, most nanosystems have been designed using a “bottom-up” approach, in which the basic components of the nanovector become assembled to achieve complex and specific behaviors. Despite the fine control of formulative conditions, the complexity of these systems often results cumbersome and difficult to scale-up. Recently, biomimetic materials emerged as a complementary or alternative design approach through a “top-down strategy”, using cell-derived materials as building blocks to formulate innovative nanovectors. The use of cell membranes as nanoparticle coatings endows nanomaterials with the biological identity and some of the functions of the cells they are derived from. In this review, we discuss some of the latest examples of membrane coated and membrane-derived biomimetic nanomaterials and underline the common general functions offered by the biomaterials used. From these examples, we suggest a systematic classification of these biomimetic materials based on their biological sources and formulation techniques, with their respective advantages and disadvantages, and summarize the current technologies used for membranes isolation and integration on nanovectors. We also discuss some current technical limitations and hint to future direction of the improvement for biomimetics.

Envelope virus-mimetic nanovaccines by hybridizing bioengineered cell membranes with bacterial vesicles

Emerging threats of rapid spread highly lethal infectious diseases highlight the urgent need of vaccine development. Here, we describe the preparation of envelope virus-mimetic nanovaccines by hybridizing bioengineered cell membranes with bacterial vesicles. Membranes acquired from bioengineered cells overexpressing viral antigens are fused with bacterial outer membrane vesicles to develop hybrid nanovesicles. Because of the presence of intact viral antigenic proteins with natural conformation bound to lipid bilayer and pathogen-associated molecular patterns, hybrid nanovesicles can strikingly promote antigen uptake, processing and presentation by dendritic cells. Immunization with envelope virus-mimetic nanovaccines shows significantly enhanced maturation and activation of dendritic cells, which elicit robust humoral and cellular immune responses in mice. By virtue of their artificial characteristic and absence of loaded adjuvants, these biomimetic nanovaccines exhibit favorable biosafety. Our work demonstrates the effectiveness of envelope virus-mimetic nanovaccines to boost antigen-specific immunity and proposes a simple yet versatile platform to prepare antiviral vaccines.

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Nanovaccines were hybridized by bioengineered cell membranes and bacterial vesicles

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Nanovaccines possessed intact viral antigens with natural conformation

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Nanovaccines promoted antigen uptake, processing, and presentation by dendritic cells

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Nanovaccines elicited robust humoral and cellular immune responses in mice