An experimental study of a novel external fixator based on universal joints for the rapid initial stabilization of mandibular comminuted fractures.

PURPOSE: Shaping and assembling contemporary external fixators rapidly for the severe mandibular fractures remains a challenge, especially in emergency circumstance. We designed a novel external fixator that incorporates universal joints to provide the stabilization for mandibular comminuted fractures. This study aims to confirm the efficacy of this novel external fixator through biomechanical tests in vitro and animal experiments. METHODS: In vitro biomechanical tests were conducted using 6 fresh canine with mandibular defect to simulate critical comminuted fractures. Three mandibles were stabilized by the novel external fixator and other mandibles were fixed by 2.5 mm reconstruction plates. All fixed mandibles were subjected to loads of 350 N on the anterior regions of teeth and 550 N on the first molar of the unaffected side. The stability was evaluated based on the maximum displacement and the slope of the load-displacement curve. In animal experiments, 9 beagles with comminuted mandibular fractures were divided into 3 groups, which were treated with novel external fixation, reconstruction plate, and dental arch bar, respectively. The general observation, the changes in animals' weight, and the surgical duration were recorded and compared among 3 groups. The CT scans were performed at various intervals of 0 day (immediately after the surgery), 3 days, 7 days, 14 days, 21 days, and 28 days to analyze the displacement of feature points on the canine mandible and situation of fracture healing at 28 days. The statistical significance was assessed by the two-way analysis of variance test followed by the Bonferroni test, enabling multiple comparisons for all tests using GraphPad Prism10.1.0 (GraphPad Inc, USA). RESULTS: The outcomes of the biomechanical tests indicated that no statistically significant differences were found in terms of the maximum displacement (p = 0.496, 0.079) and the slope of load displacement curves (p = 0.374, 0.349) under 2 load modes between the external and internal fixation groups. The animal experiment data showed that there were minor displacements of feature points between the external and internal fixation groups without statistic difference, while the arch bar group demonstrated inferior stability. The CT analysis revealed that the best fracture healing happened in the internal fixation group, followed by the external fixation and arch baring at 28 days after fixation. The external fixation group had the shortest fixation duration (25.67 ± 3.79) min compared to internal fixation ((70.67 ± 4.51) min, p < 0.001) and arch baring ((42.00 ± 3.00) min, p = 0.046). CONCLUSION: The conclusion of this study highlighted the efficacy and reliability of this novel external fixator in managing mandibular fractures rapidly, offering a viable option for the initial stabilization of comminuted mandibular fractures in the setting of emergency rescue.

RNA interference-based osteoanabolic therapy for osteoporosis by a bone-formation surface targeting delivery system.

RNA interference (RNAi)-based gene therapy that promotes anabolic bone formation is an effective approach for addressing osteoporosis. However, the selection of target gene and tissue-specific delivery systems has hindered the progression of this strategy. In this study, we identified casein kinase-2 interacting protein-1 encoding gene (Ckip-1), a negative regulator of bone formation, as an effective target of small interfering RNAs (siRNAs) for improving bone mass. Moreover, an impressive (DSS)6-Liposome (Lipos) nanoparticle system that could target the bone formation surface was synthesized to enhance the delivery of Ckip-1 siRNA to osteogenic lineage cells. The in vitro results confirmed that the (DSS)6-Lipos system could efficaciously improve the intracellular delivery of Ckip-1 siRNA without obvious cell toxicity. The in vivo application of the delivery system showed specific accumulation of siRNA in osteogenic cells located around the bone formation surface. Bone-related analysis indicated increased bone mass and improved bone microarchitecture in mice with ovariectomy-induced osteoporosis. Moreover, the biomechanical characteristics of the tibia were enhanced significantly, indicating increased resistance to fragile fracture induced by osteoporosis. Thus, (DSS)6-Lipos-Ckip-1 siRNA-based osteoanabolic therapy may be a promising option for the treatment of osteoporosis.

Mandibular Coronoidectomy Could Significantly Accelerate the Healing Process of Infratemporal Fossa Abscess.

PURPOSE: Management of an infratemporal fossa abscess (IFA), which is a specific form of severe and advanced deep fascial space infection (DFI), is based mainly on traditional methods. The purpose of this study was to investigate the role of mandibular coronoidectomy in accelerating IFA healing. PATIENTS AND METHODS: This research is a single-center retrospective study composed of 23 patients with IFA. The predictor variables were gender, age, diabetes, severity score, and mandibular coronoidectomy. The outcome variables included hospitalization time (HT) and irrigating time (IT). A comparison of treatment outcomes between the improved and traditional surgical interventions for IFA was performed. RESULTS: Compared with patients who did not receive mandibular coronoidectomy (NC group; HT, 17.54 ± 1.80 days; IT, 38.54 ± 3.73 days), patients who underwent mandibular coronoidectomy (AC group) had significantly decreased HT (7.20 ± 1.19 days) and IT (15.10 ± 1.27 days; P < .01). In addition, 4 patients (31%) in the NC group received reoperation for osteomyelitis, whereas no osteomyelitis and DFI recurrence occurred in the AC group. CONCLUSIONS: Mandibular coronoidectomy with extra intraoral drainage could considerably accelerate the healing process of IFAs and obviously decrease the reoperation rate for osteomyelitis.

Do Open Reduction and Internal Fixation With Articular Disc Anatomical Reduction and Rigid Anchorage Manifest a Promising Prospect in the Treatment of Intracapsular Fractures?

PURPOSE: In response to the increased attention to soft tissue reduction in the treatment of intracapsular condylar fractures (ICFs), a modified open reduction technique is proposed and its functional and radiographic outcomes were evaluated in this study. PATIENTS AND METHODS: This is a retrospective case series study of patients with all ICF types that were treated with open reduction and internal fixation (ORIF) with articular disc anatomic reduction and rigid anchorage. Inclusion and exclusion criteria were strictly applied. Preoperative and postoperative clinical examinations of malocclusion, maximum incisor opening (MIO), laterotrusion, and temporomandibular disorder symptoms were recorded and analyzed. Computed tomography (CT) and magnetic resonance imaging (MRI) were used to assess articular position and condylar morphology and position. RESULTS: Thirty-four patients with ICFs (47 sides) were treated with the modified ORIF technique. At 6 months of follow-up, no malocclusion was found and the MIO considerably expanded to 3.56 ± 0.13 cm. Only 4 patients (12%) had temporomandibular joint discomfort with mouth opening. Interestingly, for unilateral type B ICFs, the laterotrusion distance to the ORIF sides was notably longer than to the non-ORIF sides. Postoperative CT and MRI showed that all fragments were properly reduced and the condyles were in the normal position. Postoperative anterior disc displacement occurred in 4 sides and condylar morphologic abnormalities (slight surface roughening and articular cartilage absorption) occurred in 3 sides (6.4%). CONCLUSIONS: This modified ORIF technique, which achieved good outcomes after treatment of all ICF types, shows promise for the treatment of ICFs.

Extracellular Vesicles Derived from Neutrophils Accelerate Bone Regeneration by Promoting Osteogenic Differentiation of BMSCs.

The reconstruction of bone defects has been associated with severe challenges worldwide. Nowadays, bone marrow mesenchymal stem cell (BMSC)-based cell sheets have rendered this approach a promising way to facilitate osteogenic regeneration in vivo. Extracellular vesicles (EVs) play an essential role in intercellular communication and execution of various biological functions and are often employed as an ideal natural endogenous nanomedicine for restoring the structure and functions of damaged tissues. The perception of polymorphonuclear leukocytes (neutrophils, PMNs) as indiscriminate killer cells is gradually changing, with new evidence suggesting a role for these cells in tissue repair and regeneration, particularly in the context of bone healing. However, the role of EVs derived from PMNs (PMN-EVs) in bone regeneration remains largely unknown, with limited research being conducted on this aspect. In the current study, we investigated the effects of PMN-EVs on BMSCs and the underlying molecular mechanisms as well as the potential application of PMN-EVs in bone regeneration. Toward this end, BMSC-based cell sheets with integrated PMN-EVs (BS@PMN-EVs) were developed for bone defect regeneration. PMN-EVs were found to significantly enhance the proliferation and osteogenic differentiation of BMSCs in vitro. Furthermore, BS@PMN-EVs were found to significantly accelerate bone regeneration in vivo by enhancing the maturation of the newly formed bone in rat calvarial defects; this is likely attributable to the effect of PMN-EVs in promoting the expression of key osteogenic proteins such as SOD2 and GJA1 in BMSCs. In conclusion, our findings demonstrate the crucial role of PMN-EVs in promoting the osteogenic differentiation of BMSCs during bone regeneration. Furthermore, this study proposes a novel strategy for enhancing bone repair and regeneration via the integration of PMN-EVs with BMSC-based cell sheets.

RNA Coating Promotes Peri-Implant Osseointegration.

In addition to transmitting and carrying genetic information, RNA plays an important abiotic role in the world of nanomaterials. RNA is a natural polyanionic biomacromolecule, and its ability to promote osteogenesis by binding with other inorganic materials as an osteogenic induction agent was discovered only recently. However, whether it can promote osseointegration on implants has not been reported. Here, we investigated the effect of the RNA-containing coating materials on peri-implant osseointegration. Total RNA extracted from rat muscle tissue was used as an osteogenic induction agent, and hyaluronic acid (HA) was used to maintain its negative charge. In simulated body fluids (SBF), in vitro studies demonstrated that the resulting material encouraged calcium salt deposition. Cytological experiments showed that the RNA-containing coating induced greater cell adhesion and osteogenic differentiation in comparison to the control. The results of animal experiments showed that the RNA-containing coating had osteoinductive and bone conduction activities, which are beneficial for bone formation and osseointegration. Therefore, the RNA-containing coatings are useful for the surface modification of titanium implants to promote osseointegration.

CKIP-1-Loaded Cartilage-Affinitive Nanoliposomes Reverse Osteoarthritis by Restoring Chondrocyte Homeostasis.

Osteoarthritis (OA) is a chronic joint disease characterized by cartilage imbalance and disruption of cartilage extracellular matrix secretion. Identifying key genes that regulate cartilage differentiation and developing effective therapeutic strategies to restore their expression is crucial. In a previous study, we observed a significant correlation between the expression of the gene encoding casein kinase-2 interacting protein-1 (CKIP-1) in the cartilage of OA patients and OA severity scores, suggesting its potential involvement in OA development. To test this hypothesis, we synthesized a chondrocyte affinity plasmid, liposomes CKIP-1, to enhance CKIP-1 expression in chondrocytes. Our results demonstrated that injection of CAP-Lipos-CKIP-1 plasmid significantly improved OA joint destruction and restored joint motor function by enhancing cartilage extracellular matrix (ECM) secretion. Histological and cytological analyses confirmed that CKIP-1 maintains altered the phosphorylation of the signal transduction molecule SMAD2/3 of the transforming growth factor-ß (TGF-ß) pathway by promoting the phosphorylation of the 8T, 416S sit. Taken together, this work highlights a novel approach for the precise modulation of chondrocyte phenotype from an inflammatory to a noninflammatory state for the treatment of OA and may be broadly applicable to patients suffering from other arthritic diseases.

Manipulation and elimination of circulating tumor cells using multi-responsive nanosheet for malignant tumor therapy.

Tumor recurrence caused by metastasis is a major cause of death for patients. Thus, a strategy to manipulate the circulating tumor cells (CTCs, initiators of tumor metastasis ) and eliminate them along with the primary tumor has significant clinical significance for malignant tumor therapy. In this study, a magnet-NIR-pH multi-responsive nanosheet (Fe3O4@SiO2-GO-PEG-FA/AMP-DOX, FGPFAD) was fabricated to capture CTCs in circulation, then magnetically transport them to the primary tumor, and finally perform NIR-dependent photothermal therapy as well as acidic-environment-triggered chemotherapy to destroy both the CTCs and the primary tumor. The FGPFAD nanosheet consists of silica-coated ferroferric oxide nanoparticles (Fe3O4@SiO2, magnetic targeting agent), graphene oxide (GO, photothermal therapy agent), polyethylene glycol (PEG, antifouling agent for sustained circulation), folic acid (FA, capturer of CTCs) and antimicrobial-peptide-conjugated doxorubicin (AMP-DOX, agent for chemotherapy), in which the AMP-DOX was bound to the FGPFAD nanosheet via a cleavable Schiff base to achieve acidic-environment-triggered drug release for tumor-specific chemotherapy. Both in vitro and in vivo results indicated that the effective capture and magnetically guided transfer of CTCs to the primary tumor, as well as the multimodal tumor extermination performed by our FGPFAD nanosheet, significantly inhibited the primary tumor and its metastasis.

Injectable hybrid inorganic nanoscaffold as rapid stem cell assembly template for cartilage repair.

Cartilage injuries are often devastating and most cannot be cured because of the intrinsically low regenerative capacity of cartilage tissues. Although stem-cell therapy has shown enormous potential for cartilage repair, the therapeutic outcome has been restricted by low survival rates and poor chondrocyte differentiation in vivo. Here, we report an injectable hybrid inorganic (IHI) nanoscaffold that facilitates fast assembly, enhances survival and regulates chondrogenic differentiation of stem cells. IHI nanoscaffolds that strongly bind to extracellular matrix (ECM) proteins assemble stem cells through synergistic 3D cell-cell and cell-matrix interactions, creating a favorable physical microenvironment for stem-cell survival and differentiation in vitro and in vivo. Additionally, chondrogenic factors can be loaded into nanoscaffolds with a high capacity, which allows deep, homogenous drug delivery into assembled 3D stem-cell-derived tissues for effective control over the soluble microenvironment of stem cells. The developed IHI nanoscaffolds that assemble with stem cells are injectable. They also scavenge reactive oxygen species and timely biodegrade for proper integration into injured cartilage tissues. Implantation of stem-cell-assembled IHI nanoscaffolds into injured cartilage results in accelerated tissue regeneration and functional recovery. By establishing our IHI nanoscaffold-templated 3D stem-cell assembly method, we provide a promising approach to better overcoming the inhibitory microenvironment associated with cartilage injuries and to advance current stem-cell-based tissue engineering.

Baicalin induces human mucoepidermoid carcinoma Mc3 cells apoptosis in vitro and in vivo.

Mucoepidermoid carcinoma (MEC) is the most common malignant tumor in salivary glands and high-grade MEC in particular demonstrates little response to chemotherapy which has been used largely for palliative treatment of metastatic disease. Baicalin, one of the main active compounds of Scutellaria baicalensis, possesses anti-inflammatory, antioxidant and antitumor properties. In the present study, we investigated the growth inhibiting and apoptosis-inducing effects of baicalin on a highly metastatic human mucoepidermoid carcinoma cell line Mc3 for the first time. Baicalin exerted dose- and time-dependent antiproliferative potential against Mc3 cells as assessed by MTT assay. Baicalin treatment of Mc3 cells resulted in an accumulation of cells at the G0/G1 and G2/M phase with a concomitant decrease in cells processing to S phase as assessed by flow cytometry. Furthermore, baicalin induced apoptosis of Mc3 cells as determined by annexin V binding and PI dual staining, DNA fragmentation, nuclear condensation and in vivo tumor inhabitation. Rhodamine 123 assay indicated that baicalin caused cytotoxicity and induced apoptosis through decreasing the mitochondrial membrane potential in Mc3 cells. Our results suggest that baicalin seems to be very attractive as a new anticancer drug and a potential chemotherapeutic agent against human high-grade mucoepidermoid carcinoma.

Optimized BMSC-derived osteoinductive exosomes immobilized in hierarchical scaffold via lyophilization for bone repair through Bmpr2/Acvr2b competitive receptor-activated Smad pathway.

Mesenchymal stem cell-derived exosomes (MSC-exos), with its inherent capacity to modulate cellular behavior, are emerging as a novel cell-free therapy for bone regeneration. Herein, focusing on practical applying problems, the osteoinductivity of MSC-exos produced by different stem cell sources (rBMSCs/rASCs) and culture conditions (osteoinductive/common) were systematically compared to screen out an optimized osteogenic exosome (BMSC-OI-exo). Via bioinformatic analyses by miRNA microarray and in vitro pathway verification by gene silencing and miRNA transfection, we first revealed that the osteoinductivity of BMSC-OI-exo was attributed to multi-component exosomal miRNAs (let-7a-5p, let-7c-5p, miR-328a-5p and miR-31a-5p). These miRNAs targeted Acvr2b/Acvr1 and regulated the competitive balance of Bmpr2/Acvr2b toward Bmpr-elicited Smad1/5/9 phosphorylation. On these bases, lyophilized delivery of BMSC-OI-exo on hierarchical mesoporous bioactive glass (MBG) scaffold was developed to realize bioactivity maintenance and sustained release by entrapment in the surface microporosity of the scaffold. In a rat cranial defect model, the loading of BMSC-OI-exo efficiently enhanced the bone forming capacity of the scaffold and induced rapid initiation of bone regeneration. This paper could provide empirical bases of MSC-exo-based therapy for bone regeneration and theoretical bases of MSC-exo-induced osteogenesis mechanism. The BMSC-OI-exo-loaded MBG scaffold developed here represented a promising bone repairing strategy for future clinical application.

Multifunctional hierarchical nanohybrids perform triple antitumor theranostics in a cascaded manner for effective tumor treatment.

Gene therapy based on transfection of RNAs/DNAs offers tremendous promise for tumor treatment. However, the relatively weak therapeutic efficiency of current genetic nanohybrids in vivo has limited the application of this strategy. Herein, we fabricated multifunctional core-shell-corona nanohybrids by combining cascaded theranostics for enhanced gene therapy. The nanohybrids consist of polydopamine-modified Fe3O4 nanoparticles as core, anti-miRNA-21 oligonucleotides (anti-miRNA) strands as shell, and doxorubicin (DOX)-conjugated DNA-8pb (DOX-DNA-8bp) as corona. The polydopamine/Fe3O4 core not only serves as an active agent for local photothermal therapy under NIR irradiation, but it also provides magnetic targeting to tumor tissue for accurate treatment, which could enhance the therapeutic effect and reduce the undesired side effects to healthy tissues. The DOX-DNA-8bp corona was grafted on the anti-miRNA shell through base pairing, which could be replaced by overexpressed miRNA-21 in tumor cells due to the strong interaction between miRNA-21 and anti-miRNA, resulting in tumor-specific gene therapy through tumorigenic miRNA-21 consumption and tumor selective chemotherapy through miRNA-21-triggered DOX-DNA-8bp release in tumor cells. Moreover, the intelligent controlled release system can gradually stop the release of DOX to prevent side effects caused by drug overdose, once sufficient damage of tumor cells has occurred, due to the downregulation of miRNA-21. The results of both in vitro and in vivo analyses showed that the nanohybrids combining cascaded chemo-photo-gene therapy could effectively inhibit tumor growth, promote the survival of tumor-bearing mice, and show no visible adverse effects on these mice, resulting in a promising nanoplatform for tumor treatment. STATEMENT OF SIGNIFICANCE: Gene therapy based on transfection of RNAs/DNAs offers tremendous promise for cancer treatment. However, the relatively weak therapeutic efficiency of current genetic nanovectors in vivo that results in insufficient tumor targeting and easy decomposition/elimination of RNAs/DNAs during therapy has limited its application. Although some approaches have combined photothermal agents or antitumor drugs with RNA/DNA nanocarriers to achieve better treatment, the spatiotemporal differences in photothermal therapy, chemotherapy, and gene therapy using current nanohybrids may hinder their synergistic effect. In the present study, we fabricated multifunctional core-shell-corona nanohybrids (Fe3O4@PDA@anti-miRNA/DNA) to simultaneously perform on-demand photothermal therapy, miR-21-triggered chemotherapy, and miR-21-dependent gene therapy at the same location, which can achieve an efficient synergistic effect for precise and effective tumor treatment.

Salicylic acid-based nanomedicine with self-immunomodulatory activity facilitates microRNA therapy for metabolic skeletal disorders.

Metabolic skeletal disorders remain a major clinical challenge. The complexity of this disease requires a strategy to address the net effects of both inflammation and impaired bone formation. microRNA-based gene therapy provides several therapeutic advantages to tackle these issues. Herein, we describe a microRNA-21 (miR-21) delivery system with an additional therapeutic effect from that of the delivery carrier itself. Poly (salicylic acid) (PSA) is, for the first time, synthesized via polycondensation of salicylic acid (SA), a bioactive ingredient widely used for anti-inflammation in medicine. PSA can self-assemble into nanoparticles (PSA-NPs) and can effectively deliver genes both in vitro and in vivo. The carrier was then attached to repetitive sequences of aspartate, serine, serine (DSS)6 for delivering miRNAs specifically to bone-formation surfaces. In vitro studies showed that miR-21@PSA-NP could effectively realize the intracellular delivery of miR-21 with low toxicity, while in vivo results indicated that the miR-21@PSA-NP-DSS6 prolonged blood circulation time, enhanced bone accumulation, and significantly improved the efficacy of miR-21-based bone anabolic therapy in osteoporotic mice. The constructed delivery system (miR-21@PSA-NP-DSS6) inherited the advantages of both SA and miR-21, which could ameliorate bone-inflamed niche and rescued the impaired bone formation ability. The synergy of anti-inflammatory and pro-osteogenic effects significantly improved trabecular bone microstructure in osteoporotic mice. STATEMENT OF SIGNIFICANCE: The complexity of metabolic skeletal disorders requires a strategy to address the net effects of both inflammation and impaired bone formation. microRNA-based gene therapy provides several therapeutic advantages to tackle these issues. We develop a novel microRNA-21 delivery system with additional therapeutic effect from that of the gene carrier itself. Poly (salicylic acid) (PSA) nanoparticles, for the first time, synthesized via polycondensation of salicylic acid and can effectively deliver genes both in vitro and in vivo. The constructed delivery system (miR-21@PSA-NP-DSS6) inherited the advantages of both SA (commonly used anti-inflammation drug in medicine) and miR-21 (a pro-osteogenic molecule), which could ameliorate bone-inflamed niche, rescued impaired bone formation ability and significantly improved trabecular bone microstructure in osteoporotic mice.

N2-Polarized Neutrophils Guide Bone Mesenchymal Stem Cell Recruitment and Initiate Bone Regeneration: A Missing Piece of the Bone Regeneration Puzzle.

The role of neutrophils in bone regeneration remains elusive. In this study, it is shown that intramuscular implantation of interleukin-8 (IL-8) (commonly recognized as a chemotactic cytokine for neutrophils) at different levels lead to outcomes resembling those of fracture hematoma at various stages. Ectopic endochondral ossification is induced by certain levels of IL-8, during which neutrophils are recruited to the implanted site and are N2-polarized, which then secrete stromal cell-derived factor-1α (SDF-1α) for bone mesenchymal stem cell (BMSC) chemotaxis via the SDF-1/CXCR4 (C-X-C motif chemokine receptor 4) axis and its downstream phosphatidylinositol 3'-kinase (PI3K)/Akt pathway and ß-catenin-mediated migration. Neutrophils are pivotal for recruiting and orchestrating innate and adaptive immunocytes, as well as BMSCs at the initial stage of bone healing and regeneration. The results in this study delineate the mechanism of neutrophil-initiated bone regeneration and interaction between neutrophils and BMSCs, and innate and adaptive immunities. This work lays the foundation for research in the fields of bone regenerative therapy and biomaterial development, and might inspire further research into novel therapeutic options.

Injectable hydrogel with MSNs/microRNA-21-5p delivery enables both immunomodification and enhanced angiogenesis for myocardial infarction therapy in pigs.

Current therapeutic strategies such as angiogenic therapy and anti-inflammatory therapy for treating myocardial infarction have limited success. An effective approach may benefit from resolution of excessive inflammation combined with enhancement of angiogenesis. Here, we developed a microRNA-21-5p delivery system using functionalized mesoporous silica nanoparticles (MSNs) with additional intrinsic therapeutic effects. These nanocarriers were encapsulated into an injectable hydrogel matrix (Gel@MSN/miR-21-5p) to enable controlled on-demand microRNA-21 delivery triggered by the local acidic microenvironment. In a porcine model of myocardial infarction, we demonstrated that the released MSN complexes notably inhibited the inflammatory response by inhibiting the polarization of M1 macrophage within the infarcted myocardium, while further microRNA-21-5p delivery by MSNs to endothelial cells markedly promoted local neovascularization and rescued at-risk cardiomyocytes. The synergy of anti-inflammatory and proangiogenic effects effectively reduced infarct size in a porcine model of myocardial infarction.

Tumor-specific nanomedicine via sequential catalytic reactions for accurate tumor therapy.

Catalytic medicine based on various catalysts has attracted increasing interest for the treatment of tumors. However, the direct application of conventional catalysts may cause serious side effects to healthy tissue and low therapeutic efficiency against tumor tissue, due to their weak specificity for the tumor microenvironment (TME). Herein, a tumor-targeting and TME-responsive nanoreactor containing ferroferric oxide nanoparticles (Fe3O4 NPs) and glucose oxidase (GOD) was developed to perform hyaluronidase (HAase) and glutathione (GSH)-triggered chain catalytic reactions in tumor tissue. This nanoreactor was designed to take advantage of the unique biological molecules in tumors and several therapeutic agents to adjust the local microenvironments, and achieved satisfactory and accurate tumor therapy. The reactions started with the consumption of intratumoral glucose to inhibit tumor growth, and simultaneously produced hydrogen peroxide (H2O2) to make up for the deficiency of H2O2 in the original tumor microenvironment, resulting in the generation of a high quantity of hydroxyl radicals as a result of the catalysis of Fe3O4 NPs to further eliminate tumor tissue. The tumor-specific catalytic medicine formed by our nanocomposite guaranteed both therapeutic efficiency and accuracy, avoiding potential risks to healthy tissue and leading to a four-fold improvement in the cytotoxicity against tumor cells compared with normal cells after incubations of 48 h. In vivo data from mouse models provided further evidence for its therapeutic efficacy: the tumor growth was completely inhibited after two weeks of the synergistic therapy, which indicated the promise of our nanocomposite for tumor treatment.

A tumor-targeted nanoplatform with stimuli-responsive cascaded activities for multiple model tumor therapy.

Herein, a rambutan-like nanocomplex (PDA-SNO-GA-HA-DOX, PSGHD for short) was designed to enable effective and accurate tumor therapy. The PSGHD nanocomplex consists of an S-nitrosothiol-functionalized polydopamine (PDA-SNO) core and a gambogic acid-derivatized hyaluronic acid (HA-GA) shell with doxorubicin (DOX) as the cargo. Due to the HA section, the PSGHD nanocomplex can be rapidly and selectively internalized by tumor cells instead of healthy cells in 12 h of co-incubation. After that, the internalized PSGHD nanocomplex is able to gradually release both DOX (agent for chemotherapy) and GA (agent for enhancing thermal damage) under different tumor-specific physiological conditions (low pH and rich HAase). When 808 nm NIR radiation was employed, the PSGHD nanocomplex further demonstrated excellent photothermal conversion to increase the local temperature over 43 °C and convert SNO to nitric oxide (NO, an agent for decreasing drug-efflux). Based on the synergistic effects of NO/DOX and GA/heat, the PSGHD nanocomplex simultaneously achieved tumor-specific low-drug-efflux chemotherapy and low-temperature photothermal therapy, resulting in an eight-fold apoptosis of tumor cells over normal cells under NIR radiation. In vivo data from mouse models further showed that the PSGHD nanocomplex can completely inhibit tumor growth and significantly prolong the survival rate of tumor bearing mice in 50 days, demonstrating the high efficiency of the PSGHD nanocomplex for tumor therapy.

NDRG2 ablation reprograms metastatic cancer cells towards glutamine dependence via the induction of ASCT2.

Background: Metastasis is the most common cause of lethal outcome in various types of cancers. Although the cell proliferation related metabolism rewiring has been well characterized, less is known about the association of metabolic changes with tumor metastasis. Herein, we demonstrate that metastatic tumor obtained a mesenchymal phenotype, which is obtained by the loss of tumor suppressor NDRG2 triggered metabolic switch to glutamine metabolism. Methods: mRNA-seq and gene expression profile analysis were performed to define the differential gene expressions in primary MEC1 and metastatic MC3 cells and the downstream pathways of NDRG2. NDRG2 regulation of Fbw7-dependent c-Myc stability were determined by immunoprecipitation and protein half-life assay. Luciferase reporter and ChIP assays were used to determine the roles of Akt and c-Myc in mediating NDRG2-dependent regulation of ASCT2 in in both tumor and NDRG2-knockout MEF cells. Finally, the effect of the NDRG2/Akt/c-Myc/ASCT2 signaling on glutaminolysis and tumor metastasis were evaluated by functional experiments and clinical samples. Results: Based on the gene expression profile analysis, we identified metastatic tumor cells acquired the mesenchymal-like characteristics and displayed the increased dependency on glutamine utilization. Further, the gain of NDRG2 function blocked epithelial-mesenchymal transition (EMT) and glutaminolysis, potentially through suppression of glutamine transporter ASCT2 expression. The ASCT2 restoration reversed NDRG2 inhibitory effect on EMT program and tumor metastasis. Mechanistic study indicates that NDRG2 promoted Fbw7-dependent c-Myc degradation by inhibiting Akt activation, and subsequently decreased c-Myc-mediated ASCT2 transcription, in both tumor and NDRG2-knockout MEF cells. Supporting the biological significance, the reciprocal relationship between NDRG2 and ASCT2 were observed in multiple types of tumor tissues, and associated with tumor malignancy. Conclusions: NDRG2-dependent repression of ASCT2 presumably is the predominant route by which NDRG2 rewires glutaminolysis and blocks metastatic tumor survival. Targeting glutaminolytic pathway may provide a new strategy for the treatment of metastatic tumors.

A viscoelastic PEGylated poly(glycerol sebacate)-based bilayer scaffold for cartilage regeneration in full-thickness osteochondral defect.

Defects of either articular cartilage or subchondral bone would destroy the structural integrity and functionality of the joint. Reconstruction of osteochondral defects requires difunctional scaffolds that simultaneously induce cartilage and subchondral bone morphogenesis, however, high-performance cartilage reconstructive scaffolds remain a considerable challenge. In this study, a solvent-free urethane crosslinking and spontaneous pore-forming procedure under room temperature was proposed and optimized to produce PEGylated poly(glycerol sebacate) (PEGS) scaffolds with controllable crosslinking degrees and hierarchical macro-/micro-porosities. Based on the economical and feasible preparative approach, the viscoelastic PEGS-12h with low crosslinking degree was demonstrated to significantly stimulate chondrogenic differentiation, maintain chondrocyte phenotype and enhance cartilage matrix secretion compared to elastic polymer with high crosslinking degree, emphasizing the importance of matrix viscoelasticity in cartilage regeneration. On this basis, the viscoelastic low-crosslinked PEGS-12h was combined with the well-acknowledged osteoinductive mesoporous bioactive glass (MBG) to construct a difunctional PEGS/MBG bilayer scaffold, and evaluated in a full-thickness osteochondral defect model in vivo. The PEGS/MBG bilayer scaffold successfully reconstructed well-integrated articular hyaline cartilage and its subchondral bone in 12 weeks, exhibiting extraordinary regenerative efficiency. The results indicated that the viscoelastic PEGS scaffold and PEGS/MBG bilayer scaffold proposed in this study made an excellent candidate for cartilage and osteochondral regeneration, and was expected for clinical translation in the future.

Biological role of metabolic reprogramming of cancer cells during epithelial­mesenchymal transition (Review).

Epithelial­mesenchymal transition (EMT) is required for the distant metastasis of tumors. The degree of tumor malignancy increases as EMT progresses. Notably, the biology of tumor cells differs from that of normal cells, with regards to characteristics and energy metabolism mechanisms; abnormal glucose metabolism, excessive accumulation of fatty acids and other metabolic disorders occur in metastatic tumors. Previous studies have confirmed that the regulation of tumor cell metabolism can affect tumor metastasis and some findings have resulted in novel clinical applications. The present review aimed to provide a basis for treatments targeting the tumor EMT process and metabolic reprogramming.