YY1-mediated PTEN dephosphorylation antagonizes IR-induced DNA repair contributing to tongue squamous cell carcinoma radiosensitization.

Ionizing radiation (IR) confers a survival advantage in tongue squamous cell carcinoma (TSCC), however, IR resistance limits its efficacy. Although Yin Yang 1 (YY1) has been reported to play a role in genotoxic drug resistance by accelerating DNA repair, its role in TSCC radioresistance remains unclear. In this study, we examined YY1 mRNA and protein expression in human tongue cancer samples using qRT-PCR and western blotting, respectively. DNA array data identified YY1 mRNA expression in IR sensitivity or resistance cell lines and tissues. Tongue carcinoma primary cells and CAL27 cells with YY1 stably overexpressed or knocked-down were exposed to IR and evaluated for cell proliferation and apoptosis by CCK8-assay and caspase-3 assay, respectively. We also examined DNA damage- or repair-related indicators, such as YY1, p-H2AX, nuclear PTEN, p-PTEN, and Rad51 through Western blot analysis. Additionally, we explored the mechanism of IR-induced PTEN nuclear translocation by introducing a series of PTEN phosphorylation site mutations and co-IP assay. We observed that YY1 mRNA and protein are highly expressed in TSCC tissues, which was correlated with worse overall survival. Moreover, higher expression of YY1 and Rad51 was observed in radioresistant cells and tissues, overexpression of YY1 led to IR resistance in TSCC cells, whereas YY1 knockdown sensitized TSCC cells to IR. The underlying mechanism showed that the overexpression of YY1 upregulated nuclear PTEN and Rad51 expression, which is essential for DNA repair. IR upregulated YY1, nuclear PTEN, and Rad51; thus, knockdown of YY1 completely blocked IR-induced upregulation of nuclear PTEN/Rad51. IR upregulated PTEN phosphorylation, and mutation of the phosphorylation site of Ser380 nearly completely blocked IR-induced PTEN nuclear translocation. Furthermore, the phosphatase PP2A negatively regulated pS380-PTEN, and knockdown of YY1 completely blocked IR-induced pS380-PTEN through PP2A. In conclusion, knockdown of YY1 enhanced TSCC radiosensitivity through PP2A-mediated dephosphorylation of PTEN Ser380; thus, antagonizing the IR-induced nuclear PTEN/Rad51 axis and targeting YY1 may reverse IR resistance in TSCC.

Injectable dual drug-loaded thermosensitive liposome-hydrogel composite scaffold for vascularised and innervated bone regeneration.

Adequate blood supply and thorough innervation are essential to the survival of tissue-engineered bones. Though great progress has been created in the application of bone tissue engineering technology to bone defect repair, many challenges remain, such as insufficient vascularisation and deficient innervation in newly regenerated bone. In the present study, we addressed these challenges by manipulating the bone regeneration microenvironment in terms of vascularisation and innervation. We used a novel injectable thermosensitive liposome-hydrogel composite scaffold as a sustained-release carrier for basic fibroblast growth factor (bFGF, which promotes angiogenesis and neurogenic differentiation) and dexamethasone (Dex, which promotes osteogenic differentiation). In vitro biological assessment demonstrated that the composite scaffold had sufficient cell compatibility; it enhanced the capacity for angiogenesis in human umbilical vein endothelial cells, and the capacity for neurogenic/osteogenic differentiation in human bone marrow mesenchymal stem cells. Moreover, the introduction of bFGF/Dex liposome-hydrogel composite scaffold to bone defect sites significantly improved vascularisation and innervated bone regeneration properties in a rabbit cranial defect model. Based on our findings, the regeneration of sufficiently vascularised and innervated bone tissue through a sustained-release scaffold with excellent injectability and body temperature sensitivity represents a promising tactic towards bone defect repair.

Triple-functional injectable liposome-hydrogel composite enhances bacteriostasis and osteo/angio-genesis for advanced maxillary sinus floor augmentation.

Bone-grafting biological materials are commonly used to increase the height of the alveolar bone in the maxillary posterior region during maxillary sinus floor augmentation. However, there has been little research on the development of an injectable bone-grafting material with bacteriostatic, angiogenic, and osteogenic properties. In this work, we developed a triple-functional vancomycin/deferoxamine/dexamethasone (Van/DFO/Dex) liposome-hydrogel composite with desirable injectability. The release kinetics confirmed orderly sustained release of Van (a bacteriostat), DFO (a vascularised small molecule), and Dex (an osteogenic small molecule). In vitro findings demonstrated the favourable cytocompatibility and antibacterial ability of this composite against Staphylococcus aureus. Additionally, the angiogenic ability of human umbilical vein endothelial cells and osteogenic differentiation activity of MC3T3-E1 cells were enhanced. An in vivo bacteriostasis assay and rabbit maxillary sinus floor augmentation model corroborated the enhanced bacteriostasis and vascularised bone regeneration properties of this functionalised composite. Overall, the favourable injectability to be fit for the minimally invasive procedure, locally sustained release property, and prominent biological functions underscore the clinical potential of Van/DFO/Dex as an ideal bone-grafting material for irregular bone defect repairs, such as maxillary sinus floor augmentation.

Myocyte-specific enhancer factor 2D promotes tumorigenesis and progression in tongue squamous cell carcinoma.

Tongue squamous cell carcinoma (TSCC) ranks as one of the most common cancers worldwide and has a poor prognosis. Myocyte-specific enhancer factor 2 (MEF2D) has recently been considered as a novel factor involved in cancer development. In the present study, the function and underlying mechanism of MEF2D in TSCC were investigated. The levels of MEF2D mRNA and protein were determined in human TSCC samples by RT-qPCR and western blot, respectively. The interaction between MEF2D expression and clinicopathologic features was evaluated by IHC and analysis of clinical information. MEF2D-mediated effects on proliferation, migration, and invasion were explored in TSCC cells after transfection with MEF2D-siRNA. The results showed higher expression of MEF2D at both the mRNA and protein levels in TSCC carcinoma tissues than in paracarcinoma tissues. Furthermore, high expression of MEF2D was positively correlated with tumor differentiation and lymphatic metastasis. MEF2D knocked down TSCCA cells also had reduced proliferative, migratory, and invasive abilities compared to those of control cells. Together, these data confirmed that knockdown of MEF2D might suppress the growth and metastasis of TSCC, which further indicated that MEF2D might serve as a therapeutic target for TSCC treatment.

[Urethral guidance probe applied to surgical urethral realignment].

OBJECTIVE: To search for a safe and convenient surgical method for management of urethral disruption. METHODS: We performed urethral realignment for 18 cases of posterior urethral disruption and 4 cases of ruptured bulbous urethra using the urethral guidance probe following bladder puncture stoma. RESULTS: Urethral realignment was accomplished in 21 of the cases, 18 under epidural and 3 under local anesthesia, with the mean blood loss of 20 ml and the average operation time of 18 minutes. Open surgery was necessitated in 1 case due to the complication of bladder rupture. Routine postoperative urethral dilation extended for 3 months, and all the cases were followed up for 3 to 24 months. The maximum urine flow rate was 15-22 ml/s in 13 cases and 10-14 ml/s in 7. One case received urethral anastomosis 3 months later because of urethrostenosis. CONCLUSIONS: Urethral realignment with the urethral guidance probe is a safe, convenient and effective surgical strategy for the management of urethral disruption.

Simvastatin Improves the Jaw Bone Microstructural Defect Induced by High Cholesterol Diet in Rats by Regulating Autophagic Flux.

OBJECTIVE: The objective of this study is to evaluate the effect of simvastatin on the jaw bone microstructural defect and autophagy in rats with high cholesterol diet (HCD). METHODS: Male Sprague-Dawley rats were fed a standard rodent chow (NC group) or a high cholesterol diet for 32 weeks and the HCD-fed rats were treated with vehicle (HC group) or simvastatin (5 mg/kg orally daily for 8 weeks, HC + SIM group, and n = 10/group). The static histomorphometric changes in the jaw bone tissues in individual rats were evaluated. The relative levels of OPG, RANKL, NF-κB, LC3, and p62 in the jaw bone tissues were determined by quantitative RT-PCR and/or immunohistochemistry. RESULTS: Compared with the NC group, the HC groups had lower trabecular bone volume, trabecular thickness and trabecular number, and increased ratios of RANKL/OPG in the jaw bone, accompanied by enhanced NF-κB activation and autophagy. Simvastatin treatment inhabited these changes, including the decreased levels of serum proinflammatory cytokines and increased autophagy. CONCLUSION: Simvastatin treatment could inhibit the hyperlipidemia-induced jaw bone microstructural defect in rats by increasing autophagic flux.

Giant keratocystic odontogenic tumor of the maxillary sinus and zygoma: A case report.

Keratocystic odontogenic tumors (KCOTs), formally known as odontogenic keratocysts, are benign developmental tumors that are found primarily in the mandibular molar region and ascending ramus. The disease is characterized by aggressive growth and a high recurrence rate following surgical treatment. The present study reports the rare case of a 25-year-old male with a giant KCOT involving the right zygoma, maxillary bone and maxillary sinus. The tumor was removed using a modified treatment of enucleation, grinding and cryotherapy. Recurrence has not been observed within the eight-month follow-up period. The present study discusses the clinical features and surgical management of this case.