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Reprogramming tumor-associated macrophages (TAMs) to an inflammatory phenotype effectively increases the potential of immune checkpoint blockade (ICB) therapy. Artificial mitochondrial transplantation, an emerging and safe strategy, has made brilliant achievements in regulating the function of recipient cells in preclinic and clinic, but its performance in reprogramming the immunophenotype of TAMs has not been reported. Here, the metabolism of M2 TAMs is proposed resetting from oxidative phosphorylation (OXPHOS) to glycolysis for polarizing M1 TAMs through targeted transplantation of mannosylated mitochondria (mPEI/M1mt). Mitochondria isolated from M1 macrophages are coated with mannosylated polyethyleneimine (mPEI) through electrostatic interaction to form mPEI/M1mt, which can be targeted uptake by M2 macrophages expressed a high level of mannose receptors. Mechanistically, mPEI/M1mt accelerates phosphorylation of NF-κB p65, MAPK p38 and JNK by glycolysis-mediated elevation of intracellular ROS, thus prompting M1 macrophage polarization. In vivo, the transplantation of mPEI/M1mt excellently potentiates therapeutic effects of anti-PD-L1 by resetting an antitumor proinflammatory tumor microenvironment and stimulating CD8 and CD4 T cells dependent immune response. Altogether, this work provides a novel platform for improving cancer immunotherapy, meanwhile, broadens the scope of mitochondrial transplantation technology in clinics in the future.

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Object: The aim of the study was to investigate the safety, effectiveness, and peripheral nerve protection in ultrasound-guided microwave ablation (US-guided-MWA) for vascular malformations (VMs) closely related to peripheral nerve. Materials and methods: From August 2019 to February 2022, 31 patients with 39 VMs received US-guided-MWA. All lesions were confirmed to be closely related to the peripheral nerve by imaging evaluation. Hydrodissection was applied to protect surrounding normal tissue, including peripheral nerves. The patients were followed up at 1day, 2 days, 3 days, 1 week, 1 month, 3 months after operation. Measurements of lesion volume, volume reduction ratio (VRR), sensory and functional abnormalities of adjacent nerves, number of treatments, complication details, personal satisfaction, recurrence, and symptom improvement were recorded. Results: Among the 39 VMs, the maximum volume is 128.58ml, while the minimum volume is 0.99ml. After a mean follow-up of 13.06 ± 4.83 months, the mean numerical rating scale (NRS) score decreased from 5.13 ± 1.65 to 0.53 ± 0.83 (P<0.0001). The mean mass volume was reduced from 18.34 ± 24.68 ml to 1.35 ± 2.09 ml (P=0.0001). The VRR of all lesions was 92.06%. However, the mean number of treatments was only 1.64 ± 0.87. All patients were satisfied with the technique, with a mean satisfaction score (SC) of 9.23 ± 1.13. There were no motor function abnormalities of the related nerves. 10 patients felt numbness in the ablation area after ablation, and gradually recovered after 1 month. Conclusion: US-guided-MWA serves as a novel alternative approach for patients with VMs. Preoperative evaluation of the relationship between VMs and peripheral nerves combined with intraoperative hydrodissection is an effective and safe method to prevent nerve injury.

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Artemisinin, originally used for its antimalarial activity, has received much attention in recent years for cancer therapy. The anticancer mechanisms of artemisinin are complicated and debatable. Challenges in the delivery of artemisinin also persist because the anticancer effect of artemisinin alone is often not satisfactory when used with traditional nanocarriers. We herein report the mitochondrial delivery of artemisinin with extremely high anticancer capacity. The action mode of artemisinin in the mitochondria of cancer cells includes heme-participating and oxygen-independent conversion of artemisinin into a carbon-centered radical, which is partly converted into ROS in the presence of molecular oxygen. We reveal that artemisinin alone in the mitochondria can induce strong cancer cell apoptosis. In addition, due to the weak inhibition of GPX4 activity by artemisinin, weak ferroptosis is also observed. We further discover that GPX4 activity in MCF-7 cells is greatly inhibited by RSL3 to synergistically enhance the anticancer capacity of artemisinin via enhancing ferroptosis. The synergistic anticancer activity of artemisinin and RSL3 in the mitochondria not only improves cancer cell-killing ability, but also inhibits the re-proliferation of residual cancer cells. This study provides a new insight into developing highly efficient and practical artemisinin nanomedicines for cancer therapy.

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Nanotechnology provides a powerful tool to overcome many disadvantages of small-molecule photosensitizers for photodynamic cancer therapy, such as hydrophobicity, rapid blood clearance, low accumulation in tumor tissue and low cell penetration, etc. The occurrence of quench in photosensitizer-loaded nanoparticle greatly downregulates the ability to generate singlet oxygen with light irradiation. Stimuli-responsive nanocarriers can improve the efficacy of PDT to a certain extent. However, insufficient release of photosensitizer from either endogenous or exogenous stimuli responsive nanocarriers in the short period of light irradiation restricts full usage of the photosensitizer delivered into cancer cells. We here report a dual-step light irradiation strategy to enhance the efficacy of cancer PDT. Ce6 as a photosensitizer is loaded in singlet oxygen-sensitive micelles (Ce6-M) via self-assembly of amphiphilic polymer mPEG2000-TK-C16. After co-incubation of Ce6-M with cancer cells or i.v. injection of Ce6-M, cancer cells or tumor tissues are irradiated with light for a short time to trigger Ce6 release, and 2 h later, re-irradiated for relatively long time. The sufficient release of Ce6 in the period between twice light irradiation significantly improves the generation of singlet oxygen, leading to more efficient cancer therapeutic effects of dual-step irradiation than that of single-step irradiation for the same total irradiation time.

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Singlet oxygen is regarded as the primary cytotoxic agent in cancer photodynamic therapy (PDT). Despite the advances in optical methods to image singlet oxygen, it remains a challenge for in vivo application due to the limited tissue penetration depth of light. Up to date, no singlet oxygen-specific magnetic resonance imaging (MRI) probe has been reported. Herein, a T2 -weighted MRI probe is reported to visually detect singlet oxygen generated in PDT in vitro and in vivo. The MRI probe Ce6/Fe3 O4 -M is constructed by co-encapsulation of photosensitizer Ce6 and Fe3 O4 nanoparticles in mPEG2000 -TK-C16 micelles. Thioketal (TK) linker in the probe is highly sensitive to singlet oxygen, but lowly sensitive to other reactive oxygen species (ROS) existing in physiological and pathological environments. Singlet oxygen, generated with light irradiation, triggers the cleavage of TK, which leads to loss of surface polyethylene glycol, increment of the hydrophobicity, and aggregation of Fe3 O4 nanoparticles. Subsequently, negatively enhanced T2 -weighted MRI signal is obtained for visual detection of singlet oxygen in the solution, cancer cells, and in vivo. This oxidation responsive MRI probe is expected to hold great promise in evaluating the ability of photosensitizers to generate singlet oxygen and in predicting the therapeutic efficacies of PDT in vivo.

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The drug resistance in cancer treatment with DOX is mainly related to the overexpression of drug efflux proteins, residing in the plasma and nuclear membranes. Delivering DOX into the mitochondria, lacking drug efflux proteins, is an interesting method to overcome DOX resistance. To solve the problem of positively charged triphenylphosphonium (TPP) for mitochondrial targeting in vivo, a charge reversal strategy was developed. Methods: An acidity triggered cleavable polyanion PEI-DMMA (PD) was coated on the surface of positively charged lipid-polymer hybrid nanoparticle (DOX-PLGA/CPT) to form DOX-PLGA/CPT/PD via electrostatic interaction. The mitochondrial localization and anticancer efficacy of DOX-PLGA/CPT/PD was evaluated both in vitro and in vivo. Results: The surface negative charge of DOX-PLGA/CPT/PD prevents from rapid clearance in the blood and improved the accumulation in tumor tissue through the enhanced permeability and retention (EPR) effect. The hydrolysis of amide bonds in PD in weakly acidic tumor tissue leads to the conversion of DOX-PLGA/CPT/PD to DOX-PLGA/CPT. The positive charge of DOX-PLGA/CPT enhances the interaction with tumor cells, promotes the uptake and improves DOX contents in tumor cells. Once endocytosed by tumor cells, the exposed TPP in nanomedicine results in effective mitochondrial localization of DOX-PLGA/CPT. Afterward, DOX can release from the nanomedicine in the mitochondria, target mtDNA, induce tumor cells apoptosis and overcome DOX resistance of MCF-7/ADR breast cancer. Conclusion: Tumor acidity triggered charge reversal of TPP-containing nanomedicine and activation of mitochondrial targeting is a simple and effective strategy for the delivery of DOX into the mitochondria of cancer cells and overcoming DOX resistance of MCF-7/ADR tumor both in vitro and in vivo, providing new insight in the design of nanomedicines for cancer chemotherapy.

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Photodynamic therapy (PDT) as an alternative choice of cancer treatment method has attracted increasing attention in the past few decades. A sufficient amount of oxygen is essential for the production of singlet oxygen (1O2) in successful PDT; however, hypoxia is a typical hallmark of cancer, which is one of the most important limitation factors of PDT. To overcome the hypoxic tumour microenvironment and achieve highly efficient photodynamic cancer therapy, herein, a photosensitizer Ce6-loaded fluorinated polymeric micelle (Ce6-PFOC-PEI-M) was constructed via the self-assembly of an amphiphilic polymer prepared from perfluorooctanoic acid and branched polyethyleneimine (10 kDa). The introduction of perfluoroalkyl groups in the polymeric micelle Ce6-PFOC-PEI-M retained the oxygen-carrying capacity similar to perfluorocarbon, increased the oxygen level and overcame the hypoxia in C6 glioma cells under oxygen-deficient conditions. As a control, Ce6-OC-PEI-M without a perfluoroalkyl group could not increase the oxygen level in C6 glioma cells under the same conditions. With laser irradiation, Ce6-PFOC-PEI-M generated much more reactive oxygen species (ROS) in C6 glioma cells than Ce6-OC-PEI-M, leading to a higher phototoxicity in vitro and photodynamic tumour growth inhibition in vivo than Ce6-OC-PEI-M. Furthermore, there were no differences in the contents of Ce6 in tumour tissue between Ce6-PFOC-PEI-M and Ce6-OC-PEI-M. The higher efficacy of Ce6-PFOC-PEI-M in PDT is ascribed to its oxygen-carrying ability rather than higher content of Ce6 in the tumour. The presented fluorinated polymeric micelle could provide a new platform in the delivery of various photosensitizers and has great potential to improve the efficacy of PDT cancer therapy.

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