Tumor-derived nanovesicles enhance cancer synergistic chemo-immunotherapy by promoting cGAS/STING pathway activation and immunogenetic cell death.

AIMS: Checkpoint blockade immunotherapy is a promising therapeutic modality that has revolutionized cancer treatment; however, the therapy is only effective on a fraction of patients due to the tumor environment. In tumor immunotherapy, the cGAS-STING pathway is a crucial intracellular immune response pathway. Therefore, this study aimed to develop an immunotherapy strategy based on the cGAS-STING pathway. MATERIALS AND METHODS: The physicochemical properties of the nanoparticles EM@REV@DOX were characterized by TEM, DLS, and WB. Subcutaneous LLC xenograft tumors were used to determine the biodistribution, antitumor efficacy, and immune response. Blood samples and tissues of interest were harvested for hematological analysis and H&E staining. SIGNIFICANCE: Overall, our designed nanovesicles provide a new perspective on tumor immunotherapy by ICD and cGAS-STING pathway, promoting DCs maturation, macrophage polarization, and activating T cells, offering a meaningful strategy for accelerating the clinical development of immunotherapy. KEY FINDINGS: EM@REV@DOX accumulated in the tumor site through EPR and homing targeting effect to release REV and DOX, resulting in DNA damage and finally activating the cGAS-STING pathway, thereby promoting DCs maturation, macrophage polarization, and activating T cells. Additionally, EM@REV@DOX increased the production of pro-inflammatory cytokines (e.g., TNF-α and IFN-ß). As a result, EM@REV@DOX was effective in treating tumor-bearing mice and prolonged their lifespans. When combined with αPD-L1, EM@REV@DOX significantly inhibited distant tumor growth, extended the survival of mice, and prevented long-term postoperative tumor metastasis, exhibiting great potential in antitumor immunotherapy.

Combining photodynamic therapy and cascade chemotherapy for enhanced tumor cytotoxicity: the role of CTT2P@B nanoparticles.

The mitochondria act as the main producers of reactive oxygen species (ROS) within cells. Elevated levels of ROS can activate the mitochondrial apoptotic pathway, leading to cell apoptosis. In this study, we devised a molecular prodrug named CTT2P, demonstrating notable efficacy in facilitating mitochondrial apoptosis. To develop nanomedicine, we enveloped CTT2P within bovine serum albumin (BSA), resulting in the formulation known as CTT2P@B. The molecular prodrug CTT2P is achieved by covalently conjugating mitochondrial targeting triphenylphosphine (PPh3), photosensitizer TPPOH2, ROS-sensitive thioketal (TK), and chemotherapeutic drug camptothecin (CPT). The prodrug, which is chemically bonded, prevents the escape of drugs while they circulate throughout the body, guaranteeing the coordinated dispersion of both medications inside the organism. Additionally, the concurrent integration of targeted photodynamic therapy and cascade chemotherapy synergistically enhances the therapeutic efficacy of pharmaceutical agents. Experimental results indicated that the covalently attached prodrug significantly mitigated CPT cytotoxicity under dark conditions. In contrast, TPPOH2, CTT2, CTT2P, and CTT2P@B nanoparticles exhibited increasing tumor cell-killing effects and suppressed tumor growth when exposed to light at 660 nm with an intensity of 280 mW cm-2. Consequently, this laser-triggered, mitochondria-targeted, combined photodynamic therapy and chemotherapy nano drug delivery system, adept at efficiently promoting mitochondrial apoptosis, presents a promising and innovative approach to cancer treatment.

Triptolide with hepatotoxicity and nephrotoxicity used in local delivery treatment of myocardial infarction by thermosensitive hydrogel.

Myocardial infarction (MI) resulting from coronary artery occlusion is the leading global cause of cardiovascular disability and mortality. Anti-inflammatory treatment plays an important role in MI treatment. Triptolide (TPL), as a Chinese medicine monomer, has a variety of biological functions, including anti-inflammatory, anti-tumor, and immunoregulation. However, it has been proved that TPL is poorly water soluble, and has clear hepatotoxicity and nephrotoxicity, which seriously limits its clinical application. Herein, we designed a long-acting hydrogel platform (TPL@PLGA@F127) for MI treatment by intramyocardial injection. First, we found that the inflammatory response and immune regulation might be the main mechanisms of TPL against MI by network pharmacology. Subsequently, we prepared the hydrogel platform (TPL@PLGA@F127) and tested its effects and toxicity on normal organs in the early stage of MI (3 days after MI-operation). The results showed that TPL@PLGA@F127 could not only promote "repair" macrophages polarization (to M2 macrophage) by day 3 after MI, but also has a long-lasting anti-inflammatory effect in the later stage of MI (28 days after MI-operation). Additionally, we proved that TPL@PLGA@F127 could attenuate the toxicity of TPL by releasing it more slowly and stably. Finally, we observed the long-term effects of TPL@PLGA@F127 on MI and found that it could improve cardiac function, depress the myocardial fibrosis and protect the cardiomyocytes. In summary, this study indicated that TPL@PLGA@F127 could not only enhance the therapeutic effects of TPL on MI, but also attenuate the hepatotoxicity and nephrotoxicity, which established a strong foundation for the clinical application of TPL for MI.

Aggregation-induced emission photosensitizer/bacteria biohybrids enhance Cerenkov radiation-induced photodynamic therapy by activating anti-tumor immunity for synergistic tumor treatment.

Cerenkov radiation-induced photodynamic therapy (CR-PDT) gets rid of the limited tissue penetration depth of the external light source and provides a feasible scheme for the PDT excited by the internal light. However, due to the low luminescence intensity of Cerenkov radiation, CR-PDT alone cannot effectively inhibit tumor growth, curbing the potential clinical translation of CR-PDT. Herein, we reported an AIE-PS/bacteria biohybrid (EcN@TTVP) composed of Escherichia coli Nissle 1917 (EcN) loaded with aggregation-induced emission photosensitizer (AIE-PS) termed TTVP, which enhanced CR-PDT by activating anti-tumor immunity for synergistic tumor treatment. The preferential tumor-colonized EcN@TTVP and radiopharmaceutical 18F-fluorodeoxyglucose (18F-FDG) were administered sequentially to enable them to co-enrich in the tumor site, thereby triggering CR-PDT and promoting immunogenic tumor cell death. Most importantly, EcN acting as immunoadjuvants enhanced the maturation of dendritic cells (DCs) and priming of cytotoxic T cells (CTLs). Therefore, under the synergistic treatment of CR-PDT and immunotherapy, AIE-PS/bacteria biohybrids resulted in either efficient tumor remission or a survival prolongation in tumor-bearing mice, which presented significant advantages over single CR-PDT. Remarkably, no obvious toxic effects were observed during the treatment. In this study, we proposed a synergistic therapeutic strategy based on EcN@TTVP for combined CR-PDT and immunotherapy against tumors. Moreover, this strategy may have great potential in clinical translation and provide references for deep-seated tumor treatment. STATEMENT OF SIGNIFICANCE: PDT is restricted due to the shallow penetration depth of light into tumor tissues. Using CR as the excitation light source for PDT can overcome the aforementioned issue and greatly expand the application of PDT. However, the low efficacy of single CR-PDT limits further its applications. Therefore, the design and development of feasible strategies to improve the efficacy of CR-PDT are of immediate importance. Introducing probiotics to our study can be used not only as tumor-targeting carriers of photosensitizers but also as immunoadjuvants. Under co-stimulation by immunogenic tumor cell death triggered by CR-PDT and probiotics acting as immunoadjuvants, anti-tumor immune responses were effectively activated, thus remarkably enhancing the efficacy of CR-PDT.

Direct observation of hot-electron-enhanced thermoelectric effects in silicon nanodevices.

The study of thermoelectric behaviors in miniatured transistors is of fundamental importance for developing bottom-level thermal management. Recent experimental progress in nanothermetry has enabled studies of the microscopic temperature profiles of nanostructured metals, semiconductors, two-dimensional material, and molecular junctions. However, observations of thermoelectric (such as nonequilibrium Peltier and Thomson) effect in prevailing silicon (Si)-a critical step for on-chip refrigeration using Si itself-have not been addressed so far. Here, we carry out nanothermometric imaging of both electron temperature (Te) and lattice temperature (TL) of a Si nanoconstriction device and find obvious thermoelectric effect in the vicinity of the electron hotspots: When the electrical current passes through the nanoconstriction channel generating electron hotspots (with Te~1500 K being much higher than TL~320 K), prominent thermoelectric effect is directly visualized attributable to the extremely large electron temperature gradient (~1 K/nm). The quantitative measurement shows a distinctive third-power dependence of the observed thermoelectric on the electrical current, which is consistent with the theoretically predicted nonequilibrium thermoelectric effects. Our work suggests that the nonequilibrium hot carriers may be potentially utilized for enhancing the thermoelectric performance and therefore sheds new light on the nanoscale thermal management of post-Moore nanoelectronics.

Chlorin e6-loaded goat milk-derived extracellular vesicles for Cerenkov luminescence-induced photodynamic therapy.

PURPOSE: Photodynamic therapy (PDT) is a promising cancer treatment strategy with rapid progress in preclinical and clinical settings. However, the limitations in penetration of external light and precise delivery of photosensitizers hamper its clinical translation. As such, the internal light source such as Cerenkov luminescence (CL) from decaying radioisotopes offers new opportunities. Herein, we show that goat milk-derived extracellular vesicles (GEV) can act as a carrier to deliver photosensitizer Chlorin e6 (Ce6) and tumor-avid 18F-FDG can activate CL-induced PDT for precision cancer theranostics. METHODS: GEV was isolated via differential ultracentrifugation of commercial goat milk and photosensitizer Ce6 was loaded by co-incubation to obtain Ce6@GEV. Tumor uptake of Ce6@GEV was examined using confocal microscopy and flow cytometry. To demonstrate the ability of 18F-FDG to activate photodynamic effects against cancer cells, apoptosis rates were measured using flow cytometry, and the production of 1O2 was measured by reactive oxygen species (ROS) monitoring kit. Moreover, we used the IVIS device to detect Cherenkov radiation and Cerenkov radiation energy transfer (CRET). For animal experiments, a small-animal IVIS imaging system was used to visualize the accumulation of the GEV drug delivery system in tumors. PET/CT and CL images of the tumor site were performed at 0.5, 1, and 2 h. For in vivo antitumor therapy, changes of tumor volume, survival time, and body weight in six groups of tumor-bearing mice were monitored. Furthermore, the blood sample and organs of interest (heart, liver, spleen, lungs, kidneys, and tumor) were collected for hematological analysis, immunohistochemistry, and H&E staining. RESULTS: Confocal microscopy of 4T1 cells incubated with Ce6@GEV for 4 h revealed strong red fluorescence signals in the cytoplasm, which demonstrated that Ce6 loaded in GEV could be efficiently delivered into tumor cells. When Ce6@GEV and 18F-FDG co-existed incubated with 4T1 cells, the cell viability plummeted from more than 88.02 ± 1.30% to 23.79 ± 1.59%, indicating excellent CL-induced PDT effects. In vivo fluorescence images showed a peak tumor/liver ratio of 1.36 ± 0.09 at 24 h after Ce6@GEV injection. For in vivo antitumor therapy, Ce6@GEV + 18F-FDG group had the best tumor inhibition rate (58.02%) compared with the other groups, with the longest survival rate (35 days, 40%). During the whole treatment process, neither blood biochemical analysis nor histological observation revealed vital organ damage, suggesting the biosafety of this treatment strategy. CONCLUSIONS: The simultaneous accumulation of 18F-FDG and Ce6 in tumor tissues is expected to overcome the deficiency of traditional PDT. This strategy has the potential to extend PDT to a variety of tumors, including metastases, using targeted radiotracers to provide internal excitation of light-responsive therapeutics. We expect that our method will play a critical role in precision treatment of deep solid tumors.

Hue-indexing-based absolute phase retrieval method using a discrete hue sequence.

To achieve an effective phase unwrapping for hue-based fringe projection profilometry, this paper proposes a hue-indexing-based absolute phase retrieval method using a discrete hue sequence. First, the hue component is extracted as the wrapped phase for 3D reconstruction by projecting a programmed hue fringe pattern. Afterward, a hue-indexing sequence with a random combination of six unique hues from the hue map is designed for hue unwrapping. By assigning a hue index of the fringe geometric center, the defocusing effect in the hue unwrapping is corrected, where the fringe order of the wrapped hue is then uniquely identified. The simulations show that the root mean square (RMS) of the residual error is 2.2185×10-4 r a d, and the effectiveness of the proposed method is further verified through experiments using a plaster statue and a compressor blade. The measurement comparison of the proposed method and the coordinate measuring machine is provided, where the RMS error of the measured deviation is 4.09×10-2 m m.

Conductive nanocomposite hydrogel and mesenchymal stem cells for the treatment of myocardial infarction and non-invasive monitoring via PET/CT.

BACKGROUND: Injectable hydrogels have great promise in the treatment of myocardial infarction (MI); however, the lack of electromechanical coupling of the hydrogel to the host myocardial tissue and the inability to monitor the implantation may compromise a successful treatment. The introduction of conductive biomaterials and mesenchymal stem cells (MSCs) may solve the problem of electromechanical coupling and they have been used to treat MI. In this study, we developed an injectable conductive nanocomposite hydrogel (GNR@SN/Gel) fabricated by gold nanorods (GNRs), synthetic silicate nanoplatelets (SNs), and poly(lactide-co-glycolide)-b-poly (ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA). The hydrogel was used to encapsulate MSCs and 68Ga3+ cations, and was then injected into the myocardium of MI rats to monitor the initial hydrogel placement and to study the therapeutic effect via 18F-FDG myocardial PET imaging. RESULTS: Our data showed that SNs can act as a sterically stabilized protective shield for GNRs, and that mixing SNs with GNRs yields uniformly dispersed and stabilized GNR dispersions (GNR@SN) that meet the requirements of conductive nanofillers. We successfully constructed a thermosensitive conductive nanocomposite hydrogel by crosslinking GNR@SN with PLGA2000-PEG3400-PLGA2000, where SNs support the proliferation of MSCs. The cation-exchange capability of SNs was used to adsorb 68Ga3+ to locate the implanted hydrogel in myocardium via PET/CT. The combination of MSCs and the conductive hydrogel had a protective effect on both myocardial viability and cardiac function in MI rats compared with controls, as revealed by 18F-FDG myocardial PET imaging in early and late stages and ultrasound; this was further validated by histopathological investigations. CONCLUSIONS: The combination of MSCs and the GNR@SN/Gel conductive nanocomposite hydrogel offers a promising strategy for MI treatment.

Interpreting the Pharmacological Mechanisms of Sho-saiko-to on Thyroid Carcinoma through Combining Network Pharmacology and Experimental Evaluation.

Sho-saiko-to is a well-known traditional Chinese medicine compound and is considered to have therapeutic effects against many diseases, including thyroid cancer (TC). However, the mechanisms and therapeutic targets of Sho-saiko-to against TC remain unclear. In this study, network pharmacology, molecular docking, and cell experiments were combined to predict and verify the targets and mechanisms of the active ingredients of Sho-saiko-to against TC. The results demonstrated that the main chemical ingredients of Sho-saiko-to could suppress the viability and proliferation of TC cells, promote apoptosis through the caspase3 pathway, and induce autophagy through the PI3K-AKT pathway. In addition, Sho-saiko-to could also induce the redifferentiation of anaplastic thyroid cancer. Our study provides a novel approach for treating differentiated thyroid cancer (DTC) or radioactive iodine refractory differentiated thyroid cancer (RAIR-DTC).

Minimizing adverse effects of Cerenkov radiation induced photodynamic therapy with transformable photosensitizer-loaded nanovesicles.

BACKGROUND: Photodynamic therapy (PDT) is a promising antitumor strategy with fewer adverse effects and higher selectivity than conventional therapies. Recently, a series of reports have suggested that PDT induced by Cerenkov radiation (CR) (CR-PDT) has deeper tissue penetration than traditional PDT; however, the strategy of coupling radionuclides with photosensitizers may cause severe side effects. METHODS: We designed tumor-targeting nanoparticles (131I-EM@ALA) by loading 5-aminolevulinic acid (ALA) into an 131I-labeled exosome mimetic (EM) to achieve combined antitumor therapy. In addition to playing a radiotherapeutic role, 131I served as an internal light source for the Cerenkov radiation (CR). RESULTS: The drug-loaded nanoparticles effectively targeted tumors as confirmed by confocal imaging, flow cytometry, and small animal fluorescence imaging. In vitro and in vivo experiments demonstrated that 131I-EM@ALA produced a promising antitumor effect through the synergy of radiotherapy and CR-PDT. The nanoparticles killed tumor cells by inducing DNA damage and activating the lysosome-mitochondrial pathways. No obvious abnormalities in the hematology analyses, blood biochemistry, or histological examinations were observed during the treatment. CONCLUSIONS: We successfully engineered a nanocarrier coloaded with the radionuclide 131I and a photosensitizer precursor for combined radiotherapy and PDT for the treatment of breast cancer.

Multi-antitumor therapy and synchronous imaging monitoring based on exosome.

BACKGROUND: Tumor-derived exosomes (TEX) have shown great potential for drug delivery and tumor targeting. Here, we developed a novel multi-drug loaded exosomes nanoprobe for combined antitumor chemotherapy and photodynamic therapy, and monitoring the drug delivery capabilities with pre-targeting technique. METHODS: TEX of human colorectal cancer HCT116 was prepared, and Doxorubicin and the photodynamic therapy agent 5-aminolevulinic acid (ALA) were loaded and named as TEX@DOX@ALA. Tumor uptake was first examined using fluorescence imaging of the fluorescent dye Cy5 (TEX@DOX@ALA@Cy5). Visualization of exosome aggregation in tumor were realized by positron-emission tomography/computed tomography (PET/CT) with pre-targeting technique. Tumor-bearing mice were first injected with TEX@DOX@ALA labeled with azide (N3) (TEX@DOX@ALA@N3), and then 68Ga-(2,2'-((6-amino-1-(4,7-bis (carboxymethyl)-1,4,7-triazonan-1-yl) hexan-2-yl) azanediyl) diacetic acid-dibenzocyclooctyne (68Ga-L-NETA-DBCO) was injected after 24 h for PET/CT imaging via in vivo click chemistry. For the antitumor therapy with photodynamic and/or chemotherapy, seven groups of tumor-bearing mice with different therapy were monitored, and the tumor size, animal weight and the survival time were recorded. Furthermore, the samples of blood and interested tissues (heart, lung, liver, kidney, and spleen) were harvested for hematological analysis and H&E staining. RESULTS: The drug loading process did not influence the structure or the function of the HCT116 TEX membranes. In a fluorescence imaging experiment, higher fluorescence could be seen in tumor after TEX@DOX@ALA@Cy5 injected, and reached the highest signal at 24 h. From PET/CT images with subcutaneous and orthotopic colon tumor-bearing mice, clear radioactivity could be seen in tumors, which suggested the successes of TEX accumulation in tumors. TEX@DOX@ALA group with photodynamic therapy and chemotherapy had the best tumor inhibition effect compared with the other groups, with the longest survival time (36 days, 37.5%). No significant damage was found on histological observation and the blood biochemical analysis, which suggested the safety of the multi-drug loaded exosomes. CONCLUSIONS: We successfully engineered an exosome-based nanoprobe integrating PET imaging components and therapeutic drugs. This drug-loaded exosome system may effectively target tumors and enable synergistic chemotherapeutic and photodynamic antitumor effects.

Extracellular vesicles-based pre-targeting strategy enables multi-modal imaging of orthotopic colon cancer and image-guided surgery.

BACKGROUD: Colon cancer contributes to high mortality rates as the result of incomplete resection in tumor surgery. Multimodal imaging can provide preoperative evaluation and intraoperative image-guiding. As biocompatible nanocarriers, extracellular vesicles hold great promise for multimodal imaging. In this study, we aim to synthesized an extracellular vesicles-based nanoprobe to visualize colon cancer with positron-emission tomography/computed tomography (PET/CT) and near-infrared fluorescence (NIRF) imaging, and investigated its utility in image-guided surgery of colon cancer in animal models. RESULTS: Extracellular vesicles were successfully isolated from adipose-derived stem cells (ADSCs), and their membrane vesicles were observed under TEM. DLS detected that the hydrodynamic diameters of the extracellular vesicles were approximately 140 nm and the zeta potential was - 7.93 ± 0.24 mV. Confocal microscopy showed that extracellular vesicles had a strong binding ability to tumor cells. A click chemistry-based pre-targeting strategy was used to achieve PET imaging in vivo. PET images and the biodistribution results showed that the best pre-targeting time was 20 h, and the best imaging time was 2 h after the injection of 68 Ga-L-NETA-DBCO. The NIRF images showed that the tumor had clear images at all time points after administration of nanoparticles and the Tumor/Muscle ratio peaked at 20 h after injection. Our data also showed that both PET/CT and NIRF imaging clearly visualized the orthotopic colon cancer models, providing preoperative evaluation. Under real-time NIRF imaging, the tumor location and tumor boundary could be clearly observed. CONCLUSIONS: In brief, this novel nanoprobe may be useful for multi-modal imaging of colon cancer and NIRF image-guided surgery. More importantly, this study provides a new possibility for clinical application of extracellular vesicles as nanocarriers.

Hydrophobic insertion-based engineering of tumor cell-derived exosomes for SPECT/NIRF imaging of colon cancer.

BACKGROUND: Tumor cell-derived exosomes (TEx) have emerged as promising nanocarriers for drug delivery. Noninvasive multimodality imaging for tracing the in vivo trafficking of TEx may accelerate their clinical translation. In this study, we developed a TEx-based nanoprobe via hydrophobic insertion mechanism and evaluated its performance in dual single-photon emission computed tomography (SPECT) and near-infrared fluorescence (NIRF) imaging of colon cancer. RESULTS: TEx were successfully isolated from HCT116 supernatants, and their membrane vesicle structure was confirmed by TEM. The average hydrodynamic diameter and zeta potential of TEx were 110.87 ± 4.61 nm and -9.20 ± 0.41 mV, respectively. Confocal microscopy and flow cytometry findings confirmed the high tumor binding ability of TEx. The uptake rate of 99mTc-TEx-Cy7 by HCT116 cells increased over time, reaching 14.07 ± 1.31% at 6 h of co-incubation. NIRF and SPECT imaging indicated that the most appropriate imaging time was 18 h after the injection of 99mTc-TEx-Cy7 when the tumor uptake (1.46% ± 0.06% ID/g) and tumor-to-muscle ratio (8.22 ± 0.65) peaked. Compared with radiolabeled adipose stem cell derived exosomes (99mTc-AEx-Cy7), 99mTc-TEx-Cy7 exhibited a significantly higher tumor accumulation in tumor-bearing mice. CONCLUSION: Hydrophobic insertion-based engineering of TEx may represent a promising approach to develop and label exosomes for use as nanoprobes in dual SPECT/NIRF imaging. Our findings confirmed that TEx has a higher tumor-targeting ability than AEx and highlight the potential usefulness of exosomes in biomedical applications.