Targeting senescence-like fibroblasts radiosensitizes non-small cell lung cancer and reduces radiation-induced pulmonary fibrosis

Cancer cell radioresistance is the primary cause of the decreased curability of non–small cell lung cancer (NSCLC) observed in patients receiving definitive radiotherapy (RT). Following RT, a set of microenvironmental stress responses is triggered, including cell senescence. However, cell senescence is often ignored in designing effective strategies to resolve cancer cell radioresistance. Herein, we identify the senescence-like characteristics of cancer-associated fibroblasts (CAFs) after RT and clarify the formidable ability of senescence-like CAFs in promoting NSCLC cell proliferation and radioresistance through the JAK/STAT pathway. Specific induction of senescence-like CAF apoptosis using FOXO4-DRI, a FOXO4-p53–interfering peptide, resulted in remarkable effects on radiosensitizing NSCLC cells in vitro and in vivo. In addition, in this study, we also uncovered an obvious therapeutic effect of FOXO4-DRI on alleviating radiation-induced pulmonary fibrosis (RIPF) by targeting senescence-like fibroblasts in vivo. In conclusion, by targeting senescence, we offer a strategy that simultaneously decreases radioresistance of NSCLC and the incidence of RIPF.

Immunization with short peptide particles reveals a functional CD8+ T-cell neoepitope in a murine renal carcinoma model

BACKGROUND

Induction of CD8⁺ T cells that recognize immunogenic, mutated protein fragments in the context of major histocompatibility class I (MHC-I) is a pressing challenge for cancer vaccine development.

METHODS

Using the commonly used murine renal adenocarcinoma RENCA cancer model, MHC-I restricted neoepitopes are predicted following next-generation sequencing. Candidate neoepitopes are screened in mice using a potent cancer vaccine adjuvant system that converts short peptides into immunogenic nanoparticles. An identified functional neoepitope vaccine is then tested in various therapeutic experimental tumor settings.

RESULTS

Conversion of 20 short MHC-I restricted neoepitope candidates into immunogenic nanoparticles results in antitumor responses with multivalent vaccination. Only a single neoepitope candidate, Nesprin-2 L4492R (Nes2LR), induced functional responses but still did so when included within 20-plex or 60-plex particles. Immunization with the short Nes2LR neoepitope with the immunogenic particle-inducing vaccine adjuvant prevented tumor growth at doses multiple orders of magnitude less than with other vaccine adjuvants, which were ineffective. Nes2LR vaccination inhibited or eradicated disease in subcutaneous, experimental lung metastasis and orthotopic tumor models, synergizing with immune checkpoint blockade.

CONCLUSION

These findings establish the feasibility of using short, MHC-I-restricted neoepitopes for straightforward immunization with multivalent or validated neoepitopes to induce cytotoxic CD8⁺ T cells. Furthermore, the Nes2LR neoepitope could be useful for preclinical studies involving renal cell carcinoma immunotherapy.

Surfactant-Stripped Micelles with Aggregation-Induced Enhanced Emission for Bimodal Gut Imaging In Vivo and Microbiota Tagging Ex Vivo

Aggregation-induced emission luminogens (AIEgens) hold promise for biomedical imaging and new approaches facilitating their aggregation state are desirable for fluorescence enhancement. Herein, a series of surfactant-stripped AIEgen micelles (SSAMs) with improved fluorescence are developed by a low-temperature surfactant-stripping method to encapsulate AIEgens in temperature-sensitive Pluronic block copolymer. After stripping excessive surfactant, SSAMs exhibit altered optical properties and significantly higher fluorescence quantum yield. Using this method, a library of highly concentrated fluorescent nanoparticles are generated with tunable absorption and emission wavelengths, permitting imaging of deep tissues at different wavelengths. SSAMs remain physiologically stable and can pass safely through gastrointestinal tract (GI) without degradation in the harsh conditions, allowing for fluorescence and photoacoustic imaging of intestine with high resolution. d-amino acids (DAA), a natural metabolite for bacteria, can be chemically conjugated on the surface of SSAMs, enabling non-invasive monitoring of the microbial behavior of ex vivo fluorescently labeled gut microbiota in the GI tract.

Position-Scanning Peptide Libraries as Particle Immunogens for Improving CD8+ T-Cell Responses

Short peptides reflecting major histocompatibility complex (MHC) class I (MHC-I) epitopes frequently lack sufficient immunogenicity to induce robust antigen (Ag)-specific CD8+ T cell responses. In the current work, it is demonstrated that position-scanning peptide libraries themselves can serve as improved immunogens, inducing Ag-specific CD8+ T cells with greater frequency and function than the wild-type epitope. The approach involves displaying the entire position-scanning library onto immunogenic nanoliposomes. Each library contains the MHC-I epitope with a single randomized position. When a recently identified MHC-I epitope in the glycoprotein gp70 envelope protein of murine leukemia virus (MuLV) is assessed, only one of the eight positional libraries tested, randomized at amino acid position 5 (Pos5), shows enhanced induction of Ag-specific CD8+ T cells. A second MHC-I epitope from gp70 is assessed in the same manner and shows, in contrast, multiple positional libraries (Pos1, Pos3, Pos5, and Pos8) as well as the library mixture give rise to enhanced CD8+ T cell responses. The library mixture Pos1-3-5-8 induces a more diverse epitope-specific T-cell repertoire with superior antitumor efficacy compared to an established single mutation mimotope (AH1-A5). These data show that positional peptide libraries can serve as immunogens for improving CD8+ T-cell responses against endogenously expressed MHC-I epitopes.

Secretions from hypochlorous acid-treated tumor cells delivered in a melittin hydrogel potentiate cancer immunotherapy

Autologous tumor cells and cell-derived secretions (CDS) can induce antitumor immune responses. The conditions in which cells are cultured and treated impact CDS, and cellular insults alter their composition and function. In this study, we generated CDS from tumor cells exposed to normal culture conditions, hypoxia, cisplatin, radiotherapy, photodynamic therapy, or hypochlorous acid (HOCl). In vitro HOCl-CDS showed the strongest stimulatory effects on dendritic cells and macrophages compared to CDS generated by hypoxia, cisplatin, radiotherapy or photodynamic therapy. To improve HOCl-CDS activity at the tumor site, we loaded HOCl-CDS into a melittin-encapsulated hydrogel scaffold. When injected intratumorally, the HOCl-CDS hydrogel promoted tumor cell death, cytotoxic T lymphocyte infiltration, and tumor-associated macrophage reprogramming towards an M1 phenotype. The hydrogel inhibited tumor growth and prolonged the survival of mice bearing B16–F10 melanoma. Furthermore, hydrogel-delivered HOCl-CDS augmented the antitumor effects of immune checkpoint blockade. These results underscore the importance of the CDS generation method and delivery approach for improving cancer immunotherapy.

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HOCl-treated tumor cell-derived secretions (HOCl-CDS) is a robust immune-stimulator on dendritic cells and macrophages.

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A multifunctional HOCl-CDS hydrogel was developed by loading HOCl-CDS into a melittin-encapsulated hydrogel scaffold.

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HOCl-CDS hydrogel promoted tumor cell death, cytotoxic T lymphocyte infiltration and M1-TAM polarization in mice.

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HOCl-CDS hydrogel synergistically augmented the therapeutic effect of anti-PD-1 and further potentiated cancer immunotherapy.

Traceless antibiotic-crosslinked micelles for rapid clearance of intracellular bacteria

Effective delivery of antimicrobial agents to intracellular pathogens represents a major bottleneck for a wide variety of infectious diseases. To address this, we developed SIR-micelles(+), as a new delivery vehicle comprising antibiotic-loaded micelles with rapid self-immolation within cells for targeted delivery to macrophages, where most intracellular bacterial reside. After phagocytosis, SIR-micelles(+) rapidly release the pristine antibiotic after the cleavage of the disulfide bonds by intracellular reducing agents such as glutathione (GSH). Colistin, a hydrophilic and potent "last-resort" antibiotic used for the treatment of drug-resistant bacterial infection, was encapsulated in SIR-micelles with 40% yield and good short-term storage stability. Hydrophobic moieties and mannose ligands in SIR-micelles(+) enhanced the delivery of colistin into macrophages. The traceless and thiol-responsive release of colistin effectively eliminated intracellular Escherichia coli within twenty minutes. In a murine pneumonia model, SIR-micelles(+) significantly reduced bacterial lung burden of multidrug-resistant Klebsiella pneumoniae. Furthermore, SIR-micelles(+) improved the survival rate and reduced the bacterial burden of organs infected by intracellular bacteria transferred from donor mice. Using this formulation approach, the nephrotoxicity and neurotoxicity induced by antibiotic were reduced by about 5- 15 fold. Thus, SIR-micelles(+) represent a new class of material that can be used for targeting treatment of intracellular and drug-resistant pathogens.

Local biomaterial-assisted antitumour immunotherapy for effusions in the pleural and peritoneal cavities caused by malignancies

Malignant pleural effusion (MPE) and malignant ascites (MA), which are common but serious conditions caused by malignancies, are related to poor quality of life and high mortality. Current treatments, including therapeutic thoracentesis and indwelling pleural catheters or paracentesis and catheter drainage, are largely palliative. An effective treatment is urgently needed. MPE and MA are excellent candidates for intratumoural injections that have direct contact with tumour cells and kill tumour cells more effectively and efficiently with fewer side effects, and the fluid environment of MPE and MA can provide a homogeneous area for drug distribution. The immunosuppressive environments within the pleural and peritoneal cavities suggest the feasibility of local immunotherapy. In this review, we introduce the current management of MPE and MA, discuss the latest advances and challenges in utilizing local biomaterial-assisted antitumour therapies for the treatment of MPE and MA, and discuss further opportunities in this field.

Light-Triggered Release of Large Biomacromolecules from Porphyrin-Phospholipid Liposomes

Liposomes containing small amounts of porphyrin-phospholipid (PoP) have been shown to encapsulate small molecular weight cargos and then release them upon exposure to red light. A putative mechanism involves transient pore formation in the bilayer induced by PoP-mediated photo-oxidation of unsaturated lipids. However, little is known about the properties of such pores. This study assesses whether large carbohydrate and protein molecules could be released from PoP liposomes upon red light exposure. A small fluorophore with ∼0.5 kDa in molecular weight, fluorescently labeled dextrans of ∼5 and ∼500 kDa, and a ∼240 kDa fluorescent protein were passively entrapped in PoP liposomes. When exposed to 665 nm irradiation, liposomes containing PoP, but not liposomes lacking it, released all these cargos in a size-dependent manner that occurred with oxidation of unsaturated lipids included in the bilayer. Thus, this study demonstrates the feasibility of light-triggered release of large biomacromolecules from liposomes.

Influenza Virus Infects and Depletes Activated Adaptive Immune Responders

Influenza infections cause several million cases of severe respiratory illness, hospitalizations, and hundreds of thousands of deaths globally. Secondary infections are a leading cause of influenza's high morbidity and mortality, and significantly factored into the severity of the 1918, 1968, and 2009 pandemics. Furthermore, there is an increased incidence of other respiratory infections even in vaccinated individuals during influenza season. Putative mechanisms responsible for vaccine failures against influenza as well as other respiratory infections during influenza season are investigated. Peripheral blood mononuclear cells (PBMCs) are used from influenza vaccinated individuals to assess antigen-specific responses to influenza, measles, and varicella. The observations made in humans to a mouse model to unravel the mechanism is confirmed and extended. Infection with influenza virus suppresses an ongoing adaptive response to vaccination against influenza as well as other respiratory pathogens, i.e., Adenovirus and Streptococcus pneumoniae by preferentially infecting and killing activated lymphocytes which express elevated levels of sialic acid receptors. These findings propose a new mechanism for the high incidence of secondary respiratory infections due to bacteria and other viruses as well as vaccine failures to influenza and other respiratory pathogens even in immune individuals due to influenza viral infections.

A sulfobetaine zwitterionic polymer-drug conjugate for multivalent paclitaxel and gemcitabine co-delivery

A zwitterionic polymer-drug conjugate (ZPDC) strategy is developed for the co-delivery of paclitaxel (PTX) and gemcitabine (GEM) chemotherapeutics, as well as a near-infrared fluorescence imaging agent cyanine5.5 (Cy5.5). The well-defined ZPDC is synthesized by tandem azide-alkyne and thiol-ene click functionalization of a biodegradable acetylenyl/allyl-functionalized polylactide and zwitterionic character is conferred by sulfobetaine. It has a number-average molecular weight of 53.6 kDa, comprising 6.5% PTX and 17.7% GEM by weight. Cy5.5 moieties are readily introduced to the ZPDC via conjugation. In aqueous solutions, the ZPDC exhibits a hydrodynamic diameter of 46 nm. In vitro MIA PaCa-2 human pancreatic cancer cells show strong ZPDC cellular uptake and cytotoxicity. In mice, the ZPDC exhibits long blood circulation, effective tumor accumulation, biocompatibility, therapeutic effect, and integrated imaging capacity. Overall, this work illustrates that ZPDCs are promising systems for chemotherapy delivery and bioimaging applications.

Abstract LB182: Vaccination by liposomes and synthetic short peptide eradicated HPV-associated tumor

Human papilloma virus (HPV)-16 is associated with cervical cancers and induces expression of the E6 and E7 oncogenes. 6 major histocompatibility complex (MHC) class I (MHC-I) epitopes were predicted to be immunogenic by sequencing a murine cell line that expresses E6/E7. A liposomal vaccine made of cobalt-porphyrin-phospholipid (CoPoP) and synthetic 9-mer epitopes appended with 3 histidine residues, resulting in rapid formation of stable peptide-liposome particles. Immunization with these predicted 6 peptides led to protection from tumor challenge on mice. Of the 6 peptides screened, only the previously identified E749-57 epitope has anti-tumor efficacy. The peptide-liposome particles that formed upon mixing E7HHH49-57 with CoPoP liposomes were stable in serum and avidly taken up by immune cells in vitro and rapidly released in lysosome. As a prophylactic vaccine, liposomal E7HHH49-57 vaccine protected mice from tumor challenge and re-challenge. As a therapeutic vaccine, immunization with the synthetic short peptide at a dose of 100 ng protected mice when admixed with CoPoP liposomes, whereas 200-fold higher peptide doses were ineffective with the Poly(I:C) adjuvant. CoPoP induced strong infiltrating CD8+ T response within the tumor microenvironment with improved functional profile. Vaccine monotherapy using nanogram dosing of the E7HHH49-57 peptide admixed with CoPoP reversed the growth of large established tumors, permanently eradicating subcutaneous tumors upwards of 100 mm3, and also completely eradicated lung tumors in a metastasis model.

Citation Format: Xuedan He, Shiqi Zhou, Breandan Quinn, Dushyant Jahagirdar, Joaquin Ortega, Scott I. Abrams, Jonathan F. Lovell. Vaccination by liposomes and synthetic short peptide eradicated HPV-associated tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB182.

Metal Phenolic Network-Integrated Multistage Nanosystem for Enhanced Drug Delivery to Solid Tumors

Metal-phenolic networks (MPNs) are an emerging class of supramolecular surface modifiers with potential use in various fields including drug delivery. Here, the development of a unique MPN-integrated core-satellite nanosystem (CS-NS) is reported. The "core" component of CS-NS comprises a liposome loaded with EDTA (a metal ion chelator) in the aqueous core and DiR (a near-infrared photothermal transducer) in the bilayer. The "satellite" component comprises mesoporous silica nanoparticles (MSNs) encapsulating doxorubicin and is coated with a Cu²⁺ -tannic acid MPN. Liposomes and MSNs self-assemble into the CS-NS through adhesion mediated by the MPN. When irradiated with an 808 nm laser, CS-NS liberated the entrapped EDTA, leading to Cu²⁺ chelation and subsequent disassembly of the core-satellite nanostructure. Photo-conversion from the large assembly to the small constituent particles proceeded within 5 min. Light-triggered CS-NS disassembly enhanced the carrier and cargo penetration and accumulation in tumor spheroids in vitro and in orthotopic murine mammary tumors in vivo. CS-NS is long circulating in the blood and conferred improved survival outcomes to tumor-bearing mice treated with light, compared to controls. These results demonstrate an MPN-integrated multistage nanosystem for improved solid tumor treatment.

Design of a Thiol-Responsive, Traceless Prodrug with Rapid Self-Immolation for Cancer Chemotherapy

Prodrugs can be formed by chemical modification of the existing active pharmaceutical ingredients (APIs); however, this often sacrifices their functional efficacy. Self-immolative linkers have recently attracted attention, as they can be designed to release pristine APIs. Herein, we report a strategy to generate a self-immolative prodrug (SIP) that can release pristine doxorubicin (DOX). Compared to conventional linkers, the key SIP DOX (KSIP-DOX) developed here can rapidly and quantitatively release the API due to its strong leaving group after reduction by thiol groups, which are present in tumors. KSIP-DOX has enhanced cellular uptake and improved anticancer efficacy, demonstrating its utility for cancer treatment.

Targeted Micellar Phthalocyanine for Lymph Node Metastasis Homing and Photothermal Therapy in an Orthotopic Colorectal Tumor Model

Small-sized trastuzumab-targeted micelles (T-MP) were engineered using a surfactant-stripping approach that yielded concentrated phthalocyanines with strong near infrared absorption. T-MP accumulated more in the lymph node (LN) metastases of orthotopic colorectal cancer compared to the micelles conjugated with control IgG. Following surgical resection of the primary tumor, minimally invasive photothermal treatment of the metastatic LN with T-MP, but not the control micelles, extended mouse survival.

ABSTRACT

Tumor lymph node (LN) metastasis seriously affects the treatment prognosis. Studies have shown that nanoparticles with size of sub-50 nm can directly penetrate into LN metastases after intravenous administration. Here, we speculate through introducing targeting capacity, the nanoparticle accumulation in LN metastases would be further enhanced for improved local treatment such as photothermal therapy. Trastuzumab-targeted micelles (< 50 nm) were formulated using a unique surfactant-stripping approach that yielded concentrated phthalocyanines with strong near-infrared absorption. Targeted micellar phthalocyanine (T-MP) was an effective photothermal transducer and ablated HT-29 cells in vitro. A HER2-expressing colorectal cancer cell line (HT-29) was used to establish an orthotopic mouse model that developed metastatic disease in mesenteric sentinel LN. T-MP accumulated more in the LN metastases compared to the micelles conjugated with control IgG. Following surgical resection of the primary tumor, minimally invasive photothermal treatment of the metastatic LN with T-MP, but not the control micelles, extended mouse survival. Our findings demonstrate for the first time that targeted small-sized nanoparticles have potential to enable superior paradigms for dealing with LN metastases. [Image: see text]

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40820-021-00666-8.

Cross-linked Histone as a Nanocarrier for Gut Delivery of Hydrophobic Cargos

Delivering hydrophobic molecules through the intestine can be challenging due to limited cargo solubility and the harsh biochemical environment of the stomach. Here, we show that a protein-based nanocarrier system based on the abundant protein histone and the natural cross-linker genipin can deliver hydrophobic cargos, such as dyes and therapeutic molecules, through the gastrointestinal tract. Using hydrophobic near-infrared dyes as model cargos, a panel of potential protein carriers was screened, and histone was identified as the one with the best loading capability. The resulting nanoparticles had a positive ζ potential and were mucoadhesive. Cross-linking of the amine-rich nanocarrier with genipin was particularly effective relative to other proteins and increased the stability of the system during incubation with pepsin. Cross-linking was required for successful delivery of a hydrophobic dye to the colon of mice after oral gavage. To assess the platform for therapeutic delivery, another hydrophobic model compound, curcumin, was delivered using cross-linked histone nanoparticles in a murine colitis model and significantly alleviated the disease. Taken together, these results demonstrate that histone is a cationic, mucoadhesive, and cross-linkable protein nanocarrier that can be considered for oral delivery.

Fast Stereolithography Printing of Large-Scale Biocompatible Hydrogel Models

Large size cell-laden hydrogel models hold great promise for tissue repair and organ transplantation, but their fabrication using 3D bioprinting is limited by the slow printing speed that can affect the part quality and the biological activity of the encapsulated cells. Here a fast hydrogel stereolithography printing (FLOAT) method is presented that allows the creation of a centimeter-sized, multiscale solid hydrogel model within minutes. Through precisely controlling the photopolymerization condition, low suction force-driven, high-velocity flow of the hydrogel prepolymer is established that supports the continuous replenishment of the prepolymer solution below the curing part and the nonstop part growth. The rapid printing of centimeter-sized hydrogel models using FLOAT is shown to significantly reduce the part deformation and cellular injury caused by the prolonged exposure to the environmental stresses in conventional 3D printing methods. Embedded vessel networks fabricated through multiscale printing allows media perfusion needed to maintain the high cellular viability and metabolic functions in the deep core of the large-sized models. The endothelialization of this vessel network allows the establishment of barrier functions. Together, these studies demonstrate a rapid 3D hydrogel printing method and represent a first step toward the fabrication of large-sized engineered tissue models.

Delivery Strategies for Melittin-Based Cancer Therapy

Melittin (MLT) has been studied preclinically as an anticancer agent based on its broad lytic effects in multiple tumor types. However, unsatisfactory tissue distribution, hemolysis, rapid metabolism, and limited specificity are critical obstacles that limit the translation of MLT. Emerging drug delivery strategies hold promise for targeting, controlled drug release, reduced side effects, and ultimately improved treatment efficiency. In this review, we discuss recent advances in the use of diverse carriers to deliver MLT, with an emphasis on the design and mechanisms of action. We further outline the opportunities for MLT-based cancer immunotherapy.

Biomimetic Liposomal Nanoplatinum for Targeted Cancer Chemophototherapy

Photodynamic therapy (PDT) of cancer is limited by tumor hypoxia. Platinum nanoparticles (nano-Pt) as a catalase-like nanoenzyme can enhance PDT through catalytic oxygen supply. However, the cytotoxic activity of nano-Pt is not comprehensively considered in the existing methods to exert their multifunctional antitumor effects. Here, nano-Pt are loaded into liposomes via reverse phase evaporation. The clinical photosensitizer verteporfin (VP) is loaded in the lipid bilayer to confer PDT activity. Murine macrophage cell membranes are hybridized into the liposomal membrane to confer biomimetic and targeting features. The resulting liposomal system, termed "nano-Pt/VP@MLipo," is investigated for chemophototherapy in vitro and in vivo in mouse tumor models. At the tumor site, oxygen produced by nano-Pt catalyzation improves the VP-mediated PDT, which in turn triggers the release of nano-Pt via membrane permeabilization. The ultrasmall 3-5 nm nano-Pt enables better penetration in tumors, which is also facilitated by the generated oxygen gas, for enhanced chemotherapy. Chemophototherapy with a single injection of nano-Pt/VP@MLipo and light irradiation inhibits the growth of aggressive 4T1 tumors and their lung metastasis, and prolongs animal survival without overt toxicity.

A Potent Cancer Vaccine Adjuvant System for Particleization of Short, Synthetic CD8+ T Cell Epitopes

Short major histocompatibility complex (MHC) class I (MHC-I)-restricted peptides contain the minimal biochemical information to induce antigen (Ag)-specific CD8⁺ cytotoxic T cell responses but are generally ineffective in doing so. To address this, we developed a cobalt-porphyrin (CoPoP) liposome vaccine adjuvant system that induces rapid particleization of conventional, short synthetic MHC-I epitopes, leading to strong cellular immune responses at nanogram dosing. Along with CoPoP (to induce particle formation of peptides), synthetic monophosphoryl lipid A (PHAD) and QS-21 immunostimulatory molecules were included in the liposome bilayer to generate the "CPQ" adjuvant system. In mice, immunization with a short MHC-I-restricted peptide, derived from glycoprotein 70 (gp70), admixed with CPQ safely generated functional, Ag-specific CD8⁺ T cells, resulting in the rejection of multiple tumor cell lines, with durable immunity. When cobalt was omitted, the otherwise identical peptide and adjuvant components did not result in peptide binding and were incapable of inducing immune responses, demonstrating the importance of stable particle formation. Immunization with the liposomal vaccine was well-tolerated and could control local and metastatic disease in a therapeutic setting. Mechanistic studies showed that particle-based peptides were better taken up by antigen-presenting cells, where they were putatively released within endosomes and phagosomes for display on MHC-I surfaces. On the basis of the potency of the approach, the platform was demonstrated as a tool for in vivo epitope screening of peptide microlibraries comprising a hundred peptides.

Trans-illumination intestine projection imaging of intestinal motility in mice

Functional intestinal imaging holds importance for the diagnosis and evaluation of treatment of gastrointestinal diseases. Currently, preclinical imaging of intestinal motility in animal models is performed either invasively with excised intestines or noninvasively under anesthesia, and cannot reveal intestinal dynamics in the awake condition. Capitalizing on near-infrared optics and a high-absorbing contrast agent, we report the Trans-illumination Intestine Projection (TIP) imaging system for free-moving mice. After a complete system evaluation, we performed in vivo studies, and obtained peristalsis and segmentation motor patterns of free-moving mice. We show the in vivo typical segmentation motor pattern, that was previously shown in ex vivo studies to be controlled by intestinal pacemaker cells. We also show the effects of anesthesia on motor patterns, highlighting the possibility to study the role of the extrinsic nervous system in controlling motor patterns, which requires unanesthetized live animals. Combining with light-field technologies, we further demonstrated 3D imaging of intestine in vivo (3D-TIP). Importantly, the added depth information allows us to extract intestines located away from the abdominal wall, and to quantify intestinal motor patterns along different directions. The TIP system should open up avenues for functional imaging of the GI tract in conscious animals in natural physiological states.

Antibiotic Cross-linked Micelles with Reduced Toxicity for Multidrug-Resistant Bacterial Sepsis Treatment

One potential approach to address the rising threat of antibiotic resistance is through novel formulations of established drugs. We designed antibiotic cross-linked micelles (ABC-micelles) by cross-linking the Pluronic F127 block copolymers with an antibiotic itself, via a novel one-pot synthesis in aqueous solution. ABC-micelles enhanced antibiotic encapsulation while also reducing systemic toxicity in mice. Using colistin, a hydrophilic, potent ″last-resort" antibiotic, ABC-micelle encapsulation yield was 80%, with good storage stability. ABC-micelles exhibited an improved safety profile, with a maximum tolerated dose of over 100 mg/kg colistin in mice, at least 16 times higher than the free drug. Colistin-induced nephrotoxicity and neurotoxicity were reduced in ABC-micelles by 10-50-fold. Despite reduced toxicity, ABC-micelles preserved bactericidal activity, and the clinically relevant combination of colistin and rifampicin (co-loaded in the micelles) showed a synergistic antimicrobial effect against antibiotic-resistant strains of Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. In a mouse model of sepsis, colistin ABC-micelles showed equivalent efficacy as free colistin but with a substantially higher therapeutic index. Microscopic single-cell imaging of bacteria revealed that ABC-micelles could kill bacteria in a more rapid manner with distinct cell membrane disruption, possibly reflecting a different antimicrobial mechanism from free colistin. This work shows the potential of drug cross-linked micelles as a new class of biomaterials formed from existing antibiotics and represents a new and generalized approach for formulating amine-containing drugs.

HPV-Associated Tumor Eradication by Vaccination with Synthetic Short Peptides and Particle-Forming Liposomes

Human papilloma virus (HPV)-16 is associated with cervical cancers and induces expression of the E6 and E7 oncogenes. Using a murine cell line that expresses these, the genes are sequenced, and six predicted major histocompatibility complex (MHC) class I (MHC-I) epitopes are identified. A liposomal vaccine adjuvant based on cobalt-porphyrin-phospholipid (CoPoP) is admixed with synthetic 9-mer epitopes appended with three histidine residues, resulting in rapid formation of peptide-liposome particles. Immunization with multivalent peptides leads to protection from tumor challenge. Of the peptides screened, only the previously identified E749-57 epitope is functional. The peptide-liposome particles that form upon mixing E7HHH49-57 with CoPoP liposomes are stable in serum and are avidly taken up by immune cells in vitro. Immunization results in robust protection from tumor challenge and re-challenge. A 100 ng peptide dose protects mice in a therapeutic tumor challenge when admixed with CoPoP liposomes, whereas 200-fold higher peptide doses are ineffective with the polyinosinic-polycytidylic (poly(I:C)) adjuvant. CoPoP induces a strong infiltrating CD8+ T-cell response within the tumor microenvironment with an improved functional profile. Vaccine monotherapy using nanogram dosing of the E7HHH49-57 peptide admixed with CoPoP reverses the growth of large established tumors, eradicating subcutaneous tumors upwards of 100 mm3 . Immunization also eradicates lung tumors in a metastasis model.

Excretable, ultrasmall hexagonal NaGdF4:Yb50% nanoparticles for bimodal imaging and radiosensitization

Background

In this study, we report on the synthesis, imaging, and radiosensitizing properties of ultrasmall β-NaGdF₄:Yb50% nanoparticles as a multifunctional theranostic platform. The synthesized nanoparticles act as potent bimodal contrast agents with superior imaging properties compared to existing agents used for magnetic resonance imaging (MRI) and computed tomography (CT). Clonogenic assays demonstrated that these nanoparticles can act as effective radiosensitizers, provided that the nanoparticles are taken up intracellularly.

Results

Our ultrasmall β-NaGdF₄:Yb50% nanoparticles demonstrate improvement in T1-weighted contrast over the standard clinical MR imaging agent Gd-DTPA and similar CT signal enhancement capabilities as commercial agent iohexol. A 2 Gy dose of X-ray induced ~ 20% decrease in colony survival when C6 rat glial cells were incubated with non-targeted nanoparticles (NaGdF₄:Yb50%), whereas the same X-ray dose resulted in a ~ 60% decrease in colony survival with targeted nanoparticles conjugated to folic acid (NaGdF₄:Yb50%-FA). Intravenous administration of nanoparticles resulted in clearance through urine and feces within a short duration, based on the ex vivo analysis of Gd³⁺ ions via ICP-MS.

Conclusion

These biocompatible and in vivo clearable ultrasmall NaGdF₄:Yb50% are promising candidates for further evaluation in image-guided radiotherapy applications.

Engineered Nanoparticle Applications for Recombinant Influenza Vaccines

Influenza viruses cause seasonal epidemics and represent a pandemic risk. With current vaccine methods struggling to protect populations against emerging strains, there is a demand for a next-generation flu vaccine capable of providing broad protection. Recombinant biotechnology, combined with nanomedicine techniques, could address this demand by increasing immunogenicity and directing immune responses toward conserved antigenic targets on the virus. Various nanoparticle candidates have been tested for use in vaccines, including virus-like particles, protein and carbohydrate nanoconstructs, antigen-carrying lipid particles, and synthetic and inorganic particles modified for antigen presentation. These methods have yielded some promising results, including protection in animal models against antigenically distinct influenza strains, production of antibodies with broad reactivity, and activation of potent T cell responses. Based on the evidence of current research, it is feasible that the next generation of influenza vaccines will combine recombinant antigens with nanoparticle carriers.