Sialidase-Chimeric Bioengineered Bacteria for Tumor-Sialoglycan-Triggered Solid Tumor Therapy.

Adoptive cell therapies for solid tumors are usually limited by off-target antigens, incapable tissue infiltration, and cell function exhaustion. In contrast, bacterial cells possess the inherent competencies of preferential tumor targeting, deep tissue penetration, and high intratumoral bioactivity and represent promising alternatives to overcome these challenges. Here, a sialic-acid-responsive regulatory gene circuit is engineered into Escherichia coli MG1655 to express cytolysin of hemolysin E (HlyE). Furthermore, sialidases are bioorthogonally decorated onto the surface of azido-functionalized bioengineered bacteria for recognizing tumor sialoglycans and cleaving their sialosides into free sialic acids. As chemical inducers, sialic acids feedbackingly activate the bacterial gene circuit to produce HlyE and lyse tumor cells. This study mimics the tumor antigen-induced cytotoxin production and cell lysis that occurs in chimeric antigen receptor T (CAR-T) cells yet surmounts the intrinsic limitations of adoptive cell therapies. Moreover, sialidase-mediated tumor cell desialylation also reverses the immunosuppressive effect of glycoimmune checkpoints and further improves the therapeutic effect of solid tumors.

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.

Modularization of Regional Electronic Structure over Defect-Rich CeO2 Rods for Enhancing Photogenerated Charge Transfer and CO2 Activation.

Oxygen vacancy (OV) engineering has been widely applied in different types of metal oxide-based photocatalytic reactions. Our study has shown that the redistributed OVs resulting from voids in CeO2 rods lead to significant differences in the band structure in space. The flat energy band within the highly crystallized bulk region hinders the recombination of photogenerated carrier pairs during the transfer process. The downward curved energy band in the surface region enhances the activation of the absorbents. Therefore, the localization of the band structure through crystal structure regionalization renders V-CeO2 capable of achieving efficient utilization of photogenerated carriers. Practically, the V-CeO2 rod shows a remarkable turnover number of 190.58 µmol g-1 h-1 in CO2 photoreduction, which is ∼9.4 times higher than that of D-CeO2 (20.46 µmol g-1 h-1). The designed modularization structure in our work is expected to provide important inspiration and guidance in coordinating the kinetic behavior of carriers in OV defect-rich photocatalysts.

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.

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.

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.

La2Ti2O7 nanosheets modified by Pt quantum dots for efficient NO removal avoiding NO2 secondary pollutant.

Two-dimensional La2Ti2O7 nanosheets with regular morphology and good dispersion were prepared by the hydrothermal method under a magnetic field. Zero-dimensional Pt quantum dots (Pt-QDs) were loaded on the La2Ti2O7 nanosheets. The electron-hole separation and carrier transfer in the Pt-loaded La2Ti2O7 nanosheets were significantly enhanced. The La2Ti2O7 nanosheets loaded with 3 wt% Pt-QDs exhibit the largest NO removal efficiency of 51% and less than 3.2 ppb NO2 intermediate pollutant in 30 min. The high photocatalytic ability was attributed to the surface plasmon resonance in Pt-QDs and the enhanced electron-hole separation. A large number of e-, h+, •OH and •O2- active species were formed on the surface of Pt-loaded La2Ti2O7 nanosheets under light irradiation. The conversion pathway from NO to NO3- was verified by the in situ diffuse reflectance infrared Fourier-transform spectroscopy and DFT calculation. This work supplies a feasible approach to responsive photocatalysts for efficient, stable, and selective NO removal avoiding the NO2 secondary pollutant.

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.

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.

Direct observation of carrier migration in heterojunctions to discuss the p-n and direct Z-scheme heterojunctions.

Type II p-n heterojunction and direct Z-scheme heterojunction are identical staggered band alignments, but were reported ambiguously in many composite photocatalysts because their carriers migrate in opposite directions. In this research, metal oxides CuO, NiO and Co3O4-based heterojunctions with Na0.9Mg0.45Ti3.55O8(NMTO) were synthesized via a simple hydrothermal method. The CuO/NMTO heterojunction was demonstrated as a direct Z-scheme heterojunction, whereas the NiO/NMTO and Co3O4/NMTO heterojunctions showed type II p-n band alignment, distinguished by the direct observation of carrier migration under light illumination, and confirmed by the x-ray photoelectron spectroscopy, Mott-Schottky measurements, ultraviolet photoelectron spectra and capture experiments. These all heterojunctions enjoyed better photocatalytic performance to degrade methylene blue and antibiotics (Enrofloxacin, Metronidazole and tetracycline) than the pure NMTO, attributed to their effective separation of the photoinduced electron-hole pairs owing to the staggered band alignment. Prominently, the NiO/NMTO and Co3O4/NMTO p-n heterojunctions exhibited superior degradation ability to the CuO/NMTO Z-scheme heterojunction. The initial relative Fermi position of two semiconductors is the prerequisite to determine whether the p-n heterojunction or direct Z-scheme heterojunction is built because the electrons diffuse from one semiconductor with a higher Fermi level to another with a lower Fermi level while the holes diffuse reversely until a united Fermi level when they combine. The built-in electric field at the heterojunction interface is determined by the difference in the initial Fermi levels or work functions of two semiconductors, regulating the separation ability of photogenerated electrons and holes to affect the photocatalytic performance. Thus, the high difference in the initial Fermi levels of semiconductors is crucial in the development of heterojunctions with staggered band alignment to obtain high performance in photocatalytic reactions.

Development of novel K0.8Ni0.4Ti1.6O4 nano bamboo leaves, microstructural characterization, double absorption, and photocatalytic removal of organic pollutant.

Novel K0.8Ni0.4Ti1.6O4 (KNTO) nano bamboo leaves were prepared for the first time under a simple hydrothermal method with 3 M KOH at 320 °C over 80 min. Highly pure KNTO possessing layered structure was determined by X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM). Double absorption feature of KNTO semiconductor was revealed at band energies of 1.88 and 2.08 eV by the UV-vis diffuse reflectance spectra and confirmed by the photoluminescence (PL) spectra. The photocatalytic activity was explored by the photodegradation of MB organic dye. KNTO not only exhibits strong adsorptive ability on methylene blue (MB) in dark environment, but also possesses good photodegradation capability of 94% degradation in 60 min. Degradation mechanism revealed that the photogenerated holes play an essential role in the MB degradation process, which is confirmed by trapping experiments. The recycling experiments demonstrated very high recycling ability and durability of KNTO nano bamboo leaves, suggesting KNTO is a potential candidate for high efficiency organic pollutant removal in the wastewater treatment.

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.

Inhibition of Tumor Progression through the Coupling of Bacterial Respiration with Tumor Metabolism.

By leveraging the ability of Shewanella oneidensis MR-1 (S. oneidensis MR-1) to anaerobically catabolize lactate through the transfer of electrons to metal minerals for respiration, a lactate-fueled biohybrid (Bac@MnO2 ) was constructed by modifying manganese dioxide (MnO2 ) nanoflowers on the S. oneidensis MR-1 surface. The biohybrid Bac@MnO2 uses decorated MnO2 nanoflowers as electron receptor and the tumor metabolite lactate as electron donor to make a complete bacterial respiration pathway at the tumor sites, which results in the continuous catabolism of intercellular lactate. Additionally, decorated MnO2 nanoflowers can also catalyze the conversion of endogenous hydrogen peroxide (H2 O2 ) into generate oxygen (O2 ), which could prevent lactate production by downregulating hypoxia-inducible factor-1α (HIF-1α) expression. As lactate plays a critical role in tumor development, the biohybrid Bac@MnO2 could significantly inhibit tumor progression by coupling bacteria respiration with tumor metabolism.

MDM2 SNP309T>G polymorphism and hepatocellular carcinoma risk: a meta-analysis.

Case-control studies on the association between mouse double-minute 2 homolog (MDM2) SNP309T>G polymorphism and hepatocellular carcinoma have provided either controversial or inconclusive results. To clarify the effect of MDM2 SNP309T>G polymorphism on the risk of hepatocellular carcinoma, a meta-analysis of all case-control observational studies was performed. Pooled odds ratios (ORs) for various polymorphisms were estimated using random and fixed effects models. The Q-statistic was used to evaluate the homogeneity, and Egger and Begg tests were used to assess publication bias. Overall, the MDM2 SNP309T>G polymorphism was associated with a risk of hepatocellular carcinoma (OR = 0.68; 95% CI = 0.54-0.85 for allele contrast, p = 0.0005, phet = 0.004). The contrast of homozygotes and the recessive and dominant models produced the same pattern of results as the allele contrast. In the analysis stratified by ethnicity, significant associations were found in the Caucasian population in all of the genetic models. In addition, heterogeneity disappeared in subgroups of Caucasian subjects. Our pooled data suggest evidence for a major role of MDM2 SNP309T>G polymorphism in the carcinogenesis of hepatocellular carcinoma, especially among Caucasian populations.

Bacterial Biohybrids for Invasion of Tumor Cells Promote Antigen Cross-Presentation Through Gap Junction.

Due to inherent differences in cellular composition and metabolic behavior with host cells, tumor-harbored bacteria can discriminatorily affect tumor immune landscape. However, the mechanisms by which intracellular bacteria affect antigen presentation process between tumor cells and antigen-presenting cells (APCs) are largely unknown. The invasion behavior of attenuated Salmonella VNP20009 (VNP) into tumor cells is investigated and an attempt is made to modulate this behavior by modifying positively charged polymers on the surface of VNP. It is found that non-toxic chitosan oligosaccharide (COS) modified VNP (VNP@COS) bolsters the formation of gap junction between tumor cells and APCs by enhancing the ability of VNP to infect tumor cells. On this basis, a bacterial biohybrid is designed to promote in situ antigen cross-presentation through intracellular bacteria induced gap junction. This bacterial biohybrid also enhances the expression of major histocompatibility complex class I molecules on the surface of tumor cells through the incorporation of Mdivi-1 coupled with VNP@COS. This strategic integration serves to heighten the immunogenic exposure of tumor antigens; while, preserving the cytotoxic potency of T cells. A strategy is proposed to precisely controlling the function and local effects of microorganisms within tumors.

Probiotics functionalized with a gallium-polyphenol network modulate the intratumor microbiota and promote anti-tumor immune responses in pancreatic cancer.

The intratumor microbiome imbalance in pancreatic cancer promotes a tolerogenic immune response and triggers immunotherapy resistance. Here we show that Lactobacillus rhamnosus GG probiotics, outfitted with a gallium-polyphenol network (LGG@Ga-poly), bolster immunotherapy in pancreatic cancer by modulating microbiota-immune interactions. Upon oral administration, LGG@Ga-poly targets pancreatic tumors specifically, and selectively eradicates tumor-promoting Proteobacteria and microbiota-derived lipopolysaccharides through a gallium-facilitated disruption of bacterial iron respiration. This elimination of intratumor microbiota impedes the activation of tumoral Toll-like receptors, thus reducing immunosuppressive PD-L1 and interleukin-1ß expression by tumor cells, diminishing immunotolerant myeloid populations, and improving the infiltration of cytotoxic T lymphocytes in tumors. Moreover, LGG@Ga-poly hampers pancreatic tumor growth in both preventive and therapeutic contexts, and amplifies the antitumor efficacy of immune checkpoint blockade in preclinical cancer models in female mice. Overall, we offer evidence that thoughtfully designed biomaterials targeting intratumor microbiota can efficaciously augment immunotherapy for the challenging pancreatic cancer.

The temporal characterization of marrow lipids and adipocytes in a rabbit model of glucocorticoid-induced osteoporosis.

OBJECTIVE: To characterize the temporal changes in marrow lipids content and adipocytes in the development of glucocorticoid-induced osteoporosis (GIOP) in rabbits using MR spectroscopy. SUBJECTS AND METHODS: Twenty 20-week-old female rabbits were randomized to a control group and a GIOP group equally. Marrow lipids fraction and bone mineral density at the left proximal femur and L3-L4 vertebrae were measured by MR spectroscopy and dual-energy X-ray absorptiometry at week 0, 4, 8, and 12. Marrow adipocytes were quantitatively evaluated by histopathology. RESULTS: Marrow adiposity in the GIOP group showed a significant increase over time, with a variation of marrow lipids fraction (+35.9 %) at week 4 from baseline and it was maintained until week 12 (+75.2 %, p < 0.001 for all). The GIOP group demonstrated continuous deterioration of bone with significant difference between the two groups at week 8, followed by increased marrow fat with significant difference at week 4 (p < 0.05 for all). In comparison with the controls, marrow adipocyte density in the GIOP group increased by 57.1 % at week 8 and 35.4 % at week 12, respectively. A reduction (-13.3 %) in adipocyte mean diameter at week 8 (but an increase (+22.7 %) at week 12) were observed in the GIOP group compared with the control group (p < 0.05 for all). There was significant difference between two periods (p = 0.023) in adipocyte mean diameter in the GIOP group. The percentage area of marrow adipocytes in the GIOP group was 62.8 ± 8.7 % at week 8 and 79.2 ± 7.7 % at week 12, both of which were significantly higher than those of the controls (p < 0.05 for all). CONCLUSIONS: Marrow adipogenesis is synchronized with bone loss in the development of GIOP, which was characterized by a significant increase in the number of small-sized marrow adipocytes in the relatively early stage and concomitant volume increase later on. MR spectroscopy appears to be the most powerful tool for detecting the sequential changes in marrow lipid content.

Integrated cascade catalysis of microalgal bioenzyme and inorganic nanozyme for anti-inflammation therapy.

Combinations of multiple enzymes for cascade catalysis have been widely applied in biomedicine, but the integration of a natural bioenzyme with an inorganic nanozyme is less developed. Inspired by the abundant content of superoxide dismutase (SOD) in Spirulina platensis (SP), we establish an integrated cascade catalysis for anti-inflammation therapy by decorating catalase (CAT)-biomimetic ceria nanoparticles (CeO2) onto the SP surface via electrostatic interaction to build microalgae-based biohybrids. The biohybrids exhibit combined catalytical competence for preferentially transforming superoxide anion radicals (O2˙-) to hydrogen peroxide (H2O2), and subsequently catalyzing H2O2 disproportionation to water and oxygen. In ulcerative colitis and Crohn's disease, the biohybrids reveal a satisfactory therapeutic effect owing to the synergistic reactive oxygen species (ROS)-scavenging capacity, suggesting a new train of thought for enzyme-based biomedical application.

Colon-targeted bacterial hydrogel for tumor vascular normalization and improved chemotherapy.

The endogenous H2S plays an important role in the occurrence and development of colon cancer, and is related to the abnormal blood vessels. Here, we reported on a sulfhydryl hyaluronid-based hydrogel (HA-SH) synthesized by amide reaction and further obtained a bacterial hydrogel by loading Thiobacillus denitrificans to the hydrogel for targeting adhesion to the colon. It was found that the loaded bacteria in HA-SH hydrogel can scavenge excess H2S in colon cancer, then promote tumor vascular normalization and improve the delivery of chemotherapy drug CPT to inhibit tumor progression. Both in vivo and in vitro experiments show that the self-crosslinked bacterial hydrogel has satisfactory effects in inhibiting tumor progression and promoting tumor vascular normalization in colon cancer. This study presents an efficient method to target the colon and consume overexpressed H2S in colon cancer to inhabit tumor progression, providing a new way for oral drug treatment of colon cancer.