Ligand-Induced Atomically Segregation-Tunable Alloy Nanoprobes for Enhanced Magnetic Resonance Imaging.

Bimetallic iron-noble metal alloy nanoparticles have emerged as promising contrast agents for magnetic resonance imaging (MRI) due to their biocompatibility and facile control over the element distribution. However, the inherent surface energy discrepancy between iron and noble metal often leads to Fe atom segregation within the nanoparticle, resulting in limited iron-water molecule interactions and, consequently, diminished relaxometric performance. In this study, we present the development of a class of ligand-induced atomically segregation-tunable alloy nanoprobes (STAN) composed of bimetallic iron-gold nanoparticles. By manipulating the oxidation state of Fe on the particle surface through varying molar ratios of oleic acid and oleylamine ligands, we successfully achieve surface Fe enrichment. Under the application of a 9 T MRI system, the optimized STAN formulation, characterized by a surface Fe content of 60.1 at %, exhibits an impressive r1 value of 2.28 mM-1·s-1, along with a low r2/r1 ratio of 6.2. This exceptional performance allows for the clear visualization of hepatic tumors as small as 0.7 mm in diameter in vivo, highlighting the immense potential of STAN as a next-generation contrast agent for highly sensitive MR imaging.

Three-dimensional printing template for intraoperative localization of pulmonary nodules in the pleural cavity.

Objectives: Localization of pulmonary nodules is challenging. However, traditional localization methods have high radiation doses and a high risk of complications. We developed a noninvasive 3-dimensional printing navigational template for intraoperative localization. It can reduce puncture-related complications and simplify the localization process. This study will verify the feasibility of this method. Methods: Patients with peripheral pulmonary nodules were included in this study. The computed tomography scan sequences were obtained to design a digital template model, which was then imported into a 3-dimensional printer to produce a physical navigational template. Finally, the navigational template is placed into the patient's pleural cavity for intraoperative localization. The precision of the nodule localization and associated complications were evaluated. Results: Twelve patients were finally included in this study. Intraoperative navigational template localization was used in all patients. The success rate of intraoperative nodule localization was 100%, and the median time of localization was 19.5 minutes (range, 16-23.5 minutes). The deviation median of the navigational template was 2.1 mm (range, 1.1-2.7 mm). Among the included patients, no significant complications occurred during intraoperative localization. Conclusions: The 3-dimensional printing template for intraoperative localization is feasible, will cause no trauma to the patient, and has acceptable accuracy for application in nodules localization. This navigational template greatly simplifies the localization process and may potentially break the dependence of percutaneous localization on computed tomography scanning.

FBCU-Net: A fine-grained context modeling network using boundary semantic features for medical image segmentation.

The performance of deep learning-based medical image segmentation methods largely depends on the segmentation accuracy of tissue boundaries. However, since the boundary region is at the junction of areas of different categories, the pixels located at the boundary inevitably carry features belonging to other classes and difficult to distinguish. This paper proposes a fine-grained contextual modeling network for medical image segmentation based on boundary semantic features, FBCU-Net, which uses the semantic features of boundary regions to reduce the influence of irrelevant features on boundary pixels. First, based on the discovery that indistinguishable pixels are usually boundary pixels in medical images, we introduce new supervision information to find and classify boundary pixels. Second, based on the existing relational context modeling schemes, we generate the boundary region representations representing the semantic features of boundary regions. Last, we use boundary region representations to reduce the influence of irrelevant features on boundary pixels and generate highly discriminative pixel representations. Furthermore, to enhance the attention of the network to the boundary region, we also propose the boundary enhancement strategy. We evaluate the proposed model on five datasets, TUI (Thyroid Tumor), ISIC-2018 (Dermoscopy), 2018 Data Science Bowl (Cell Nuclei), Glas (Colon Cancer), and BUSI (Breast Cancer). The results show that FBCU-Net has better boundary segmentation performance and overall performance for different medical images than other state-of-the-art (SOTA) methods, and has great potential for clinical application.

A light-activated magnetic bead strategy utilized in spatio-temporal controllable exosomes isolation.

Tumor-derived exosomes are considered as a key biomarker in the field of liquid biopsy. However, conventional separation techniques such as ultracentrifugation, co-precipitation and column chromatography cannot isolate samples with high throughput, while traditional immunomagnetic separation techniques, due to steric effect of magnetic beads, reducing sensitivity of exosomes optical detection. Herein, we provide a novel and simple nanoplatform for spatiotemporally controlling extraction and elution of exosomes via magnetic separation and light-activated cargo release. In this system, magnetic beads are co-modified by photoresponsive groups -nitrobenzyl group and aptamers that are compatible with CD63-a highly expressed exosomal surface-specific protein. Through exosomes extracted from cell model and nude mice xenograft tumor model morphological characterization and proteomic analysis, results showed that our novel magnetic bead system outperformed current ultracentrifugation in serum exosome extraction in terms of extraction time, yield, and proportion of populations with high CD63 expression. This strategy may be a powerful tool for exosome isolation in clinical liquid biopsies of cancer disease.

A Peritumorally Injected Immunomodulating Adjuvant Elicits Robust and Safe Metalloimmunotherapy against Solid Tumors.

Clinical immunotherapy of solid tumors elicits durable responses only in a minority of patients, largely due to the highly immunosuppressive tumor microenvironment (TME). Although rational combinations of vaccine adjuvants with inflammatory cytokines or immune agonists that relieve immunosuppression represent an appealing therapeutic strategy against solid tumors, there are unavoidable nonspecific toxicities due to the pleiotropy of cytokines and undesired activation of off-target cells. Herein, a Zn2+ doped layered double hydroxide (Zn-LDH) based immunomodulating adjuvant, which not only relieves immunosuppression but also elicits robust antitumor immunity, is reported. Peritumorally injected Zn-LDH sustainably neutralizes acidic TME and releases abundant Zn2+ , promoting a pro-inflammatory network composed of M1-tumor-associated macrophages, cytotoxic T cells, and natural-killer cells. Moreover, the Zn-LDH internalized by tumor cells effectively disrupts endo-/lysosomes to block autophagy and induces mitochondrial damage, and the released Zn2+ activates the cGas-STING signaling pathway to induce immunogenic cell death, which further promotes the release of tumor-associated antigens to induce antigen-specific cytotoxic T lymphocytes. Unprecedentedly, merely injection of Zn-LDH adjuvant, without using any cytotoxic inflammatory cytokines or immune agonists, significantly inhibits the growth, recurrence, and metastasis of solid tumors in mice. This study provides a rational bottom-up design of potent adjuvant for cancer metalloimmunotherapy against solid tumors.

Cofilin-1 and phosphoglycerate kinase 1 as promising indicators for glioma radiosensibility and prognosis.

Glioma is a primary malignancy in central nervous system. Radiotherapy has been used as one of the standard treatments for glioma for decades. Since radioresistance can reduce the curative efficacy of radiotherapy in glioma, investigating the cause of radioresistance and predicting the tumour radiosensibility appeared particularly important. We previously reported that CFL1 and PGK1 are over-expressed in radioresistant U251 glioma cells. In this study, the level of CFL1 and PGK1 of 113 glioma tissues were measured by ELISA method. The relevance of the expression of these two proteins to radiosensibility was analyzed by mean test and multivariate logistic regression. The survival analysis was carried out in 85 irradiated patients and 105 followed-up patients respectively. The relationship between protein expression and clinical parameters was explored in overall 113 patients, and the correlation between CFL1 and PGK1 were determined as well. Our results showed that the expression of CFL1 and PGK1 were significantly higher (P < 0.001) in radioresistant patients than others. The multivariate Logistic regression demonstrated that the expression of CFL1 (p < 0.001) and PGK1 (p < 0.001) were associated with radioresistance in glioma. The multivariate Cox regression in overall survival suggested that CFL1 level or PGK1 level could be the independent prognosis factor for poor prognosis in 113 glioma patients. In addition, CFL1 expression was positively correlated with PGK1 expression in glioma. The results suggested that as promising indicators, CFL1 and PGK1 could be used to evaluate glioma radiosensibility and prognosis. These two proteins could also be the potential therapeutic targets of glioma.

Inhibition of the Rac1-WAVE2-Arp2/3 signaling pathway promotes radiosensitivity via downregulation of cofilin-1 in U251 human glioma cells.

The Ras-related C3 botulinum toxin substrate 1 (Rac1)-WASP-family verprolin-homologous protein-2 (WAVE2)-actin-related protein 2/3 (Arp2/3) signaling pathway has been identified to be involved in cell migration and invasion in various types of cancer cell. Cofilin­1 (CFL­1), which is regulated by the Rac1­WAVE2­Arp2/3 signaling pathway, may promote radioresistance in glioma. Therefore, the present study aimed to investigate the potential role of the Rac1­WAVE2­Arp2/3 signaling pathway in radioresistance in U251 human glioma cells and elucidate its affect on CFL­1 expression. Western blot analysis was performed to evaluate the protein expression of CFL­1. In the present study, Rac1 was inhibited by NSC 23766, WAVE2 was inhibited by transfection with short hairpin (sh)RNA­WAVE2 using Lipofectamine™ 2000 and Arp2/3 was inhibited by CK­666. Cell viability was measured using the 3­(4,5­dimethylthiazol­2­yl)-2,5­diphenyltetrazolium bromide assay, the cell migration ability was examined by a wound­healing assay, and the cell invasion ability was assessed using a Transwell culture chamber system. The results showed that inhibition of the Rac1­WAVE2­Arp2/3 signaling pathway using NSC 23766, shRNA­WAVE2 or CK­666 reduced the cell viability, migration and invasion abilities in U251 human glioma cells, concordant with a reduced expression of CFL­1. Furthermore, the expression of CFL­1 was significantly increased in radioresistant U251 glioma cells when compared with normal U251 human glioma cells. These findings indicate that inhibition of the Rac1­WAVE2­Arp2/3 signaling pathway may promote radiosensitivity, which may partially result from the downregulation of CFL­1 in U251 human glioma cells.

Silencing of the TPM1 gene induces radioresistance of glioma U251 cells.

The present study was designed to investigate the relationship between tropomyosin 1 (TPM1) and radioresistance in human U251 cells. Radioresistant U251 (RR-U251) cells were established by repeated small irradiating injury. TPM1 levels in the U251 and RR-U251 cells were inhibited by transfection with TPM1-short hairpin RNA (shRNA) while overexpression was induced by treatment with pcDNA3.1­TPM1. The radiosensitivity of the U251 and RR-U251 cells and the plasmid-transfected cells was evaluated by cell viability, migration and invasion assays. Cell apoptosis was also examined in vitro. The radiosensitivity of U251 xenografts was observed by tumor growth curve after radiotherapy in an in vivo experiment. Western blotting and immunohistochemistry were used to detect the level of TPM1 in vivo. The expression of TPM1 was significantly decreased in the RR-U251 cells, which may be correlated with the radioresistance of the glioma U251 cells. In the TPM1-silenced RR-U251 and TPM1-silenced U251 cells, cell viability, migration and invasion ability were significantly increased, and the rate of cell apoptosis was decreased. Consistent with these results, in the TPM1-overexpressing U251 and RR-U251 cells, cell viability, migration and invasion abilities were markedly decreased, and increased apoptosis was noted when compared to the control group. Tumor growth of the U251 xenografts was significantly inhibited following treatment with pcDNA3.1­TPM1 combined with radiotherapy. Taken together, these results indicate that TPM1 may be one mechanism underlying radiation resistance, and TPM1 may be a potential target for overcoming the radiation resistance in glioma.