Immunoadjuvant-Modified Rhodobacter sphaeroides Potentiate Cancer Photothermal Immunotherapy.

Photothermal immunotherapy has become a promising strategy for tumor treatment. However, the intrinsic drawbacks like light instability, poor immunoadjuvant effect, and poor accumulation of conventional inorganic or organic photothermal agents limit their further applications. Based on the superior carrying capacity and active tumor targeting property of living bacteria, an immunoadjuvant-intensified and engineered tumor-targeting bacterium was constructed to achieve effective photothermal immunotherapy. Specifically, immunoadjuvant imiquimod (R837)-loaded thermosensitive liposomes (R837@TSL) were covalently decorated onto Rhodobacter sphaeroides (R.S) to obtain nanoimmunoadjuvant-armed bacteria (R.S-R837@TSL). The intrinsic photothermal property of R.S combined R837@TSL to achieve in situ near-infrared (NIR) laser-controlled release of R837. Meanwhile, tumor immunogenic cell death (ICD) caused by photothermal effect of R.S-R837@TSL, synergizes with released immunoadjuvants to promote maturation of dendritic cells (DCs), which enhance cytotoxic T lymphocytes (CTLs) infiltration for further tumor eradication. The photosynthetic bacteria armed with immunoadjuvant-loaded liposomes provide a strategy for immunoadjuvant-enhanced cancer photothermal immunotherapy.

In Situ Formed Microalgae-Integrated Living Hydrogel for Enhanced Tumor Starvation Therapy and Immunotherapy through Photosynthetic Oxygenation.

The effectiveness of various cancer therapies for solid tumors is substantially limited by the highly hypoxic tumor microenvironment (TME). Here, a microalgae-integrated living hydrogel (ACG gel) is developed to concurrently enhance hypoxia-constrained tumor starvation therapy and immunotherapy. The ACG gel is formed in situ following intratumoral injection of a biohybrid fluid composed of alginate, Chlorella sorokiniana, and glucose oxidase, facilitated by the crossing-linking between divalent ions within tumors and alginate. The microalgae Chlorella sorokiniana embedded in ACG gel generate abundant oxygen through photosynthesis, enhancing glucose oxidase-catalyzed glucose consumption and shifting the TME from immunosuppressive to immunopermissive status, thus reducing the tumor cell energy supply and boosting antitumor immunity. In murine 4T1 tumor models, the ACG gel significantly suppresses tumor growth and effectively prevents postoperative tumor recurrence. This study, leveraging microalgae as natural oxygenerators, provides a versatile and universal strategy for the development of oxygen-dependent tumor therapies.

Metabolic Regulation-Mediated Reversion of the Tumor Immunosuppressive Microenvironment for Potentiating Cooperative Metabolic Therapy and Immunotherapy.

Tumor cells exhibit heightened glucose (Glu) consumption and increased lactic acid (LA) production, resulting in the formation of an immunosuppressive tumor microenvironment (TME) that facilitates malignant proliferation and metastasis. In this study, we meticulously engineer an antitumor nanoplatform, denoted as ZLGCR, by incorporating glucose oxidase, LA oxidase, and CpG oligodeoxynucleotide into zeolitic imidazolate framework-8 that is camouflaged with a red blood cell membrane. Significantly, ZLGCR-mediated consumption of Glu and LA not only amplifies the effectiveness of metabolic therapy but also reverses the immunosuppressive TME, thereby enhancing the therapeutic outcomes of CpG-mediated antitumor immunotherapy. It is particularly important that the synergistic effect of metabolic therapy and immunotherapy is further augmented when combined with immune checkpoint blockade therapy. Consequently, this engineered antitumor nanoplatform will achieve a cooperative tumor-suppressive outcome through the modulation of metabolism and immune responses within the TME.

Intracellular Gelation-Mediated Living Bacteria for Advanced Biotherapeutics in Mouse Models.

Despite its significant potential in various disease treatments and diagnostics, microbiotherapy is consistently plagued by multiple limitations ranging from manufacturing challenges to in vivo functionality. Inspired by the strategy involving nonproliferating yet metabolically active microorganisms, we report an intracellular gelation approach that can generate a synthetic polymer network within bacterial cells to solve these challenges. Specifically, poly(ethylene glycol dimethacrylate) (PEGDA, 700 Da) monomers are introduced into the bacterial cytosol through a single cycle of freeze-thawing followed by the initiation of intracellular free radical polymerization by UV light to create a macromolecular PEGDA gel within the bacterial cytosol. The molecular crowding resulting from intracytoplasmic gelation prohibits bacterial division and confers robust resistance to simulated gastrointestinal fluids and bile acids while retaining the ability to secrete functional proteins. Biocompatibility assessments demonstrate that the nondividing gelatinized bacteria are effective in alleviating systemic inflammation triggered by intravenous Escherichia coli injection. Furthermore, the therapeutic efficacy of gelatinized Lactobacillus rhamnosus in colitis mice provides additional support for this approach. Collectively, intracellular gelation indicates a universal strategy to manufacture next-generation live biotherapeutics for advanced microbiotherapy.

Engineered Living Bacteriophage-Enabled Self-Adjuvanting Hydrogel for Remodeling Tumor Microenvironment and Cancer Therapy.

Due to the complexity and heterogeneity in the tumor microenvironment, the efficacy of breast cancer treatment has been significantly impeded. Here, we established a living system using an engineered M13 bacteriophage through chemical cross-linking and biomineralization to remodel the tumor microenvironment. Chemically cross-linking of the engineered bacteriophage gel (M13 Gel) could in situ synthesize photothermal palladium nanoparticles (PdNPs) on the pVIII capsid protein to obtain M13@Pd Gel. In addition, NLG919 was further loaded into a gel to form (M13@Pd/NLG gel) for down-regulating the expression of tryptophan metabolic enzyme indoleamine 2,3-dioxygenase 1 (IDO1). Both in vitro and in vivo studies showed that the M13 bacteriophage served not only as a cargo-loaded device but also as a self-immune adjuvant, which induced the immunogenic death of tumor cells effectively and down-regulated IDO1 expression. Such a bioactive gel system constructed by natural living materials could reverse immunosuppression and significantly improve the anti-breast cancer response.

Two-Pronged Microbe Delivery of Nitric Oxide and Oxygen for Diabetic Wound Healing.

Chronic inflammation and hypoxia in the microenvironment of diabetic foot ulcers (DFUs) can result in sustained vascular impairment, hindering tissue regeneration. While both nitric oxide and oxygen have been shown to promote wound healing in DFUs through anti-inflammatory and neovascularization, there is currently no available therapy that delivers both. We present a novel hydrogel consisting of Weissella and Chlorella, which alternates between nitric oxide and oxygen production to reduce chronic inflammation and hypoxia. Further experiments indicate that the hydrogel accelerates wound closure, re-epithelialization, and angiogenesis in diabetic mice and improves the survival of skin grafts. This dual-gas therapy holds promise as a potential treatment option for the management of diabetic wounds.

FNIII14 Peptide-Enriched Membrane Nanocarrier to Disrupt Stromal Barriers through Reversing CAFs for Augmenting Drug Penetration in Tumors.

Given the key roles of cancer associated fibroblasts (CAFs) in shaping tumor stroma, this study shows a CAF-associated ITGB1-inactivating peptide-enriched membrane nanodelivery system (designated as PMNPs-D) to simultaneously target CAFs and tumor cells for boosted chemotherapy through promoted drug perfusion. In the structure of PMNPs-D, the PLGA-based inner core is loaded with the chemotherapeutic drug doxorubicin, and the outer surface is cloaked by hybrid biomembranes with the insertion of integrin ß1 (ITGB1) inhibiting peptide (i.e., FNIII14). After prolonged blood circulation and actively targeting in tumor sites, PMNPs-D can respond to CAF-overexpressed fibroblast activation protein-α (FAP-α) to trigger the release of FNIII14, which will bind to ITGB1 and inhibit CAFs' biological function in producing the stromal matrix, thereby loosening the condensed stromal structure and enhancing the permeability of nanotherapeutics in tumors. As a result, this tailor-designed nanosystem shows substantial tumor inhibition and metastasis retardation in aggressive adenoid cystic carcinoma (ACC) tumor-harboring mice.

Autonomously Assembled Living Capsules by Microbial Coculture for Enhanced Bacteriotherapy of Inflammatory Bowel Disease.

Microorganism-mediated self-assembling of living formulations holds great promise for disease therapy. Here, we constructed a prebiotic-probiotic living capsule (PPLC) by coculturing probiotics (EcN) with Gluconacetobacter xylinus (G. xylinus) in a prebiotic-containing fermentation broth. Through shaking the culture, G. xylinus secretes cellulose fibrils that can spontaneously encapsulate EcN to form microcapsules under shear forces. Additionally, the prebiotic present in the fermentation broth is incorporated into the bacterial cellulose network through van der Waals forces and hydrogen bonding. Afterward, the microcapsules were transferred to a selective LB medium, which facilitated the colonization of dense probiotic colonies within them. The in vivo study demonstrated that PPLC-containing dense colonies of EcN can antagonize intestinal pathogens and restore microbiota homeostasis by showing excellent therapeutic performance in treating enteritis mice. The in situ self-assembly of probiotics and prebiotics-based living materials provides a promising platform for the treatment of inflammatory bowel disease.

Bioorthogonal "Click and Release" Reaction-Triggered Aggregation of Gold Nanoparticles Combined with Released Lonidamine for Enhanced Cancer Photothermal Therapy.

Cancer has been the most deadly disease, and 13 million cancer casualties are estimated to occur each year by 2030. Gold nanoparticles (AuNPs)-based photothermal therapy (PTT) has attracted great interest due to its high spatiotemporal controllability and noninvasiveness. Due to the trade-off between particle size and photothermal efficiency of AuNPs, rational design is needed to realize aggregation of AuNPs into larger particles with desirable NIR adsorption in tumor site. Exploiting the bioorthogonal "Click and Release" (BCR) reaction between iminosydnone and cycloalkyne, aggregation of AuNPs can be achieved and attractively accompanied by the release of chemotherapeutic drug purposed to photothermal synergizing. We synthesize iminosydnone-lonidamine (ImLND) as a prodrug and choose dibenzocyclooctyne (DBCO) as the trigger of BCR reaction. A PEGylated AuNPs-based two-component nanoplatform consisting of prodrug-loaded AuNPs-ImLND and tumor-targeting peptide RGD-conjugated AuNPs-DBCO-RGD is designed. In the therapeutic regimen, AuNPs-DBCO-RGD are intravenously injected first for tumor-specific enrichment and retention. Once the arrival of AuNPs-ImLND injected later at tumor site, highly photothermally active nanoaggregates of AuNPs are formed via the BCR reaction between ImLND and DBCO. The simultaneous release of lonidamine further enhanced the therapeutic performance by sensitizing cancer cells to PTT.

Self-Assembled Copper-Based Nanoparticles for Glutathione Activated and Enzymatic Cascade-Enhanced Ferroptosis and Immunotherapy in Cancer Treatment.

As an emerging cancer treatment strategy, ferroptosis is greatly restricted by excessive glutathione (GSH) in tumor microenvironment (TME) and low reactive oxygen species (ROS) generation efficiency. Here, this work designs self-assembled copper-alanine nanoparticles (CACG) loaded with glucose oxidase (GOx) and cinnamaldehyde (Cin) for in situ glutathione activated and enzymatic cascade-enhanced ferroptosis and immunotherapy. In response to GSH-rich and acidic TME, CACG allows to effectively co-deliver Cu2+ , Cin, and GOx into tumors. Released Cin consumes GSH through Michael addition, accompanying with the reduction of Cu2+ into Cu+ for further GSH depletion. With the cascade of Cu+ -catalyzed Fenton reactions and enzyme-catalyzed reactions by GOx, CACG could get rid of the restriction of insufficient hydrogen peroxide in TME, leading to a robust and constant generation of ROS. With the high efficiency of GSH depletion and ROS production, ferroptosis is significantly enhanced by CACG in vivo. Moreover, elevated oxidative stress triggers robust immune responses by promoting dendritic cells maturation and T cell infiltration. The in vivo results prove that CACG could efficiently inhibit tumor growth in 4T1 tumor-bearing mouse model without causing obvious systemic toxicity, suggesting the great potential of CACG in enhancing ferroptosis and immunotherapy for effective cancer treatment.

Apoptotic Body-Mediated Intracellular Delivery Strategy for Enhanced STING Activation and Improved Tumor Immunogenicity.

Agonists of stimulators of interferon genes (STING) are a promising class of immunotherapeutics that trigger potent innate immunity. However, the therapeutic efficacy of conventional STING agonists, such as 2',3'-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), is severely restricted to poor cytosolic delivery and lacks the capacity to promote the recognition of tumor-specific antigens. Here, we tackle these challenges through a nanovaccine platform based on Fenton-reactive and STING-activating nanoparticles, synergistically contributing to the generation of tumor-cell-derived apoptotic bodies (ABs). ABs loaded with exogenous cGAMP are readily phagocytosed by antigen-presenting cells (APCs), as a Trojan horse for rendering tumor cells with high immunogenicity instead of a noninflammatory response. This leads to enhanced STING activation and an improved tumor-specific antigen presentation ability, boosting the adaptive immunity in collaboration with innate immune. The strategy of exploiting a metal-based nanovaccine platform possesses great potential to be clinically translated into a trinitarian system of diagnosis, treatment, and prognosis.

Probiotic Spore-Based Oral Drug Delivery System for Enhancing Pancreatic Cancer Chemotherapy by Gut-Pancreas-Axis-Guided Delivery.

The chemotherapeutic effectiveness of pancreatic ductal adenocarcinoma (PDAC) is severely hampered by insufficient intratumoral delivery of antitumor drugs. Here, we demonstrate that enhanced pancreatic cancer chemotherapy can be achieved by probiotic spore-based oral drug delivery system via gut-pancreas axis translocation. Clostridium butyricum spores resistant to harsh external stress are extracted as drug carriers, which are further covalently conjugated with gemcitabine-loaded mesoporous silicon nanoparticles (MGEM). The spore-based oral drug delivery system (SPORE-MGEM) migrates upstream into pancreatic tumors from the gut, which increases intratumoral drug accumulation by ∼3-fold compared with MGEM. In two orthotopic PDAC mice models, tumor growth is markedly suppressed by SPORE-MGEM without obvious side effects. Leveraging the biological contact of the gut-pancreas axis, this probiotic spore-based oral drug delivery system reveals a new avenue for enhancing PDAC chemotherapy.

Double Bacteria Synergistic Catalytic Reduction System for Heavy Metal Detoxification Treatment.

Synthetic biology has promoted the development of microbial therapy, but the scope of applicable microbial species is limited and transgenic microorganisms also display safety risks for in vivo applications. Interestingly, symbiotic microorganisms in nature can achieve functional updates by metabolic cooperation. Here, we report on a nongenetic method for engineering microorganisms to construct a heavy metal ion reduction system, which was prepared by linking Shewanella oneidensis MR-1 (SO) and Lactobacillus rhamnosus GG (LGG). SO could reduce metal ions but is limited by finite substrates in vivo. LGG could metabolize glucose to lactate as a substrate for SO, promoting extracellular electron transfer by SO and heavy metal ion reduction. Meanwhile, SO could generate electron donor cytochrome C to promote metabolism of LGG, forming metabolic synergy and circulation between these two bacteria. The SO-LGG system shows splendid ability to remove heavy metal ions and inflammatory modulation in acute or chronic heavy metal poisoning.

Interference of Glucose Bioavailability of Tumor by Engineered Biohybrids for Potentiating Targeting and Uptake of Antitumor Nanodrugs.

The chemotherapy efficacy of nanodrugs is restricted by poor tumor targeting and uptake. Here, an engineered biohybrid living material (designated as EcN@HPB) is constructed by integrating paclitaxel and BAY-876 bound human serum albumin nanodrugs (HPB) with Escherichia coli Nissle 1917 (EcN). Due to the inherent tumor tropism of EcN, EcN@HPB could actively target the tumor site and competitively deprive glucose through bacterial respiration. Thus, albumin would be used as an alternative nutrient source for tumor metabolism, which significantly promotes the internalization of HPB by tumor cells. Subsequently, BAY-876 internalized along with HPB nanodrugs would further depress glucose uptake of tumor cells via inhibiting glucose transporter 1 (GLUT1). Together, the decline of glucose bioavailability of tumor cells would activate and promote the macropinocytosis in an AMP-activated protein kinase (AMPK)-dependent manner, resulting in more uptake of HPB by tumor cells and boosting the therapeutic outcome of paclitaxel.

Large π-Conjugated Metal-Organic Frameworks for Infrared-Light-Driven CO2 Reduction.

It remains challenging to excite traditional photocatalysts through near-infrared (NIR) light. Attempts to use NIR-light-response materials for photochemical reduction usually suffer from inapposite band position due to extremely narrow band gaps. Here, we report that large π-conjugated organic semiconductor engineered metal-organic framework (MOF) can result in NIR-light-driven CO2 reduction catalyst with high photocatalytic activity. A series of mesoporous MOFs, with progressively increased macrocyclic π-conjugated units, were synthesized for tuning the light adsorption range and catalytic performance. Attainment of these MOFs in single-crystal form revealed the identical topology and precise spatial arrangements of constituent organic semiconductor units and metal clusters. Furthermore, the ultrafast spectroscopic studies confirmed the formation of charge separation state and the mechanism underlying photoexcited dynamics. This combined with X-ray photoelectron spectroscopy and in situ electron paramagnetic resonance studies verified the photoinduced electron transfer pathway within MOFs for NIR-light-driven CO2 reduction. Specifically, tetrakis(4-carboxybiphenyl)naphthoporphyrin) MOF (TNP-MOF) photocatalyst displayed an unprecedentedly high CO2 reduction rate of over 6630 µmol h-1 g-1 under NIR light irradiation, and apparent quantum efficiencies (AQE) at 760 and 808 nm were over 2.03% and 1.11%, respectively. The photocatalytic performance outperformed all the other MOF-based photocatalysts, even visible-light-driven MOF-based catalysts.

Tumor Antigen Loaded Nanovaccine Induced NIR-Activated Inflammation for Enhanced Antigen Presentation During Immunotherapy of Tumors.

Although anticancer vaccines have achieved certain effects in early clinical practice, T cell immunity as the most common responsive pattern of anticancer vaccines is still limited by unsatisfied tumor recognition and inhibition efficiency. As the critical step of T cell immunity, uptake and presentation of specific antigen by antigen-presenting cells (APC) can be activated by inflammation for enhancing the response of T cells to the antigen source. Here, a hybrid nanovaccine named PTh/MnO2 @M activated with a near-infrared ray (NIR) is prepared by coating an autologous tumor cell membrane on the surface of a polythiophene/MnO2 composite core. The photoelectrical material polythiophene can produce local microinflammation under NIR radiation and activate specific T cell antitumor immunity by promoting APC maturation and autologous tumor antigens presentation. Moreover, the synthesized nanovaccine PTh/MnO2 @M is shown to induce a significant antitumor immune response, effectively inhibit the progression of melanoma in mice, and significantly prolong the survival time of mice in vivo. This strategy aims to enhance T-cell immune responses by promoting antigen presentation, leading to effective and specific cancer therapy.

Cell primitive-based biomimetic functional materials for enhanced cancer therapy.

Cell primitive-based functional materials that combine the advantages of natural substances and nanotechnology have emerged as attractive therapeutic agents for cancer therapy. Cell primitives are characterized by distinctive biological functions, such as long-term circulation, tumor specific targeting, immune modulation etc. Moreover, synthetic nanomaterials featuring unique physical/chemical properties have been widely used as effective drug delivery vehicles or anticancer agents to treat cancer. The combination of these two kinds of materials will catalyze the generation of innovative biomaterials with multiple functions, high biocompatibility and negligible immunogenicity for precise cancer therapy. In this review, we summarize the most recent advances in the development of cell primitive-based functional materials for cancer therapy. Different cell primitives, including bacteria, phages, cells, cell membranes, and other bioactive substances are introduced with their unique bioactive functions, and strategies in combining with synthetic materials, especially nanoparticulate systems, for the construction of function-enhanced biomaterials are also summarized. Furthermore, foreseeable challenges and future perspectives are also included for the future research direction in this field.

Customized materials-assisted microorganisms in tumor therapeutics.

Microorganisms have been extensively applied as active biotherapeutic agents or drug delivery vehicles for antitumor treatment because of their unparalleled bio-functionalities. Taking advantage of the living attributes of microorganisms, a new avenue has been opened in anticancer research. The integration of customized functional materials with living microorganisms has demonstrated unprecedented potential in solving existing questions and even conferring microorganisms with updated antitumor abilities and has also provided an innovative train of thought for enhancing the efficacy of microorganism-based tumor therapy. In this review, we have summarized the emerging development of customized materials-assisted microorganisms (MAMO) (including bacteria, viruses, fungi, microalgae, as well as their components) in tumor therapeutics with an emphasis on the rational utilization of chosen microorganisms and tailored materials, the ingenious design of biohybrid systems, and the efficacious antitumor mechanisms. The future perspectives and challenges in this field are also discussed.

Photoelectric Bacteria Enhance the In Situ Production of Tetrodotoxin for Antitumor Therapy.

Engineered bacteria are promising bioagents to synthesize antitumor drugs at tumor sites with the advantages of avoiding drug leakage and degradation during delivery. Here, we report an optically controlled material-assisted microbial system by biosynthesizing gold nanoparticles (AuNPs) on the surface of Shewanella algae K3259 (S. algae) to obtain Bac@Au. Leveraging the dual directional electron transport mechanism of S. algae, the hybrid biosystem enhances in situ synthesis of antineoplastic tetrodotoxin (TTX) for a promising antitumor effect. Because of tumor hypoxia-targeting feature of facultative anaerobic S. algae, Bac@Au selectively target and colonize at tumor. Upon light irradiation, photoelectrons produced by AuNPs deposited on bacterial surface are transferred into bacterial cytoplasm and participate in accelerated cell metabolism to increase the production of TTX for antitumor therapy. The optically controlled material-assisted microbial system enhances the efficiency of bacterial drug synthesis in situ and provides an antitumor strategy that could broaden conventional therapy boundaries.

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

Tumor heterogeneity, often leading to metastasis, limits the development of tumor therapy. Personalized therapy is promising to address tumor heterogeneity. Here, a vesicle system was designed to enhance innate immune response and amplify personalized immunotherapy. Briefly, the bacterial outer membrane vesicle (OMV) was hybridized with the cell membrane originated from the tumor (mT) to form new functional vesicles (mTOMV). In vitro experiments revealed that the mTOMV strengthened the activation of innate immune cells and increased the specific lysis ability of T cells in homogeneous tumors. In vivo experiments showed that the mTOMV effectively accumulated in inguinal lymph nodes, then inhibited lung metastasis. Besides, the mTOMV evoked adaptive immune response in homologous tumor rather than the heterogeneous tumor, reversibly demonstrating the effects of personalized immunotherapy. The functions to inhibit tumor growth and metastasis accompanying good biocompatibility and simple preparation procedure of mTOMV provide their great potential for clinical applications.