OBJECTIVE: To investigate the expression and clinical significance of Rad52, a homologous recombination repair gene, in tissues of nasopharyngeal carcinoma (NPC). METHOD: The expression of Rad52 was detected with three-step immunohistochemistry technique in tissues of 38 NPC patients and which have the corresponding paracancerous tissues. All of the Rad52 expression and clinical data (gender, age, clinical stage ) were compared and analyzed to conclude the relationship between them. RESULT: The Rad52 expressions were significantly different from NPC tissues to peri-NPC tissues (P < 0.05). It was found by Spearman analysis method that the Rad52 expression decreased with patients'clinical stages (P < 0.05), but has no significant relationship with gender, age, recurrence, and lymphonode metastasis (P > 0.05). The expression of Rad52 influenced the survival time of NPC patients significantly (P < 0.05). CONCLUSION The Rad52 expression can be a useful prognostic and treatment factor for NPC patients.
Adult ; Carcinoma ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Middle Aged ; Nasopharyngeal Carcinoma ; Nasopharyngeal Neoplasms ; metabolism ; Neoplasm Staging ; Rad52 DNA Repair and Recombination Protein ; metabolism ; Survival Rate ; Young Adult

Objective: To investigate the feasibility of chitin as bone substitute material and carrier of rhBMP2.Methods: Porous chitin and chitin/rhBMP2/collagen complex were implanted into calvarial defects in 8 rabbits. Bone repairing ability was assessed by radiographic and histological observation. 2 rabbits without implantation were served as controls. Results: Chitin had certain bone conductive ability. When combined with rhBMP2,a complex possessing both bone conductive activity and bone inductive activity was produced. The complex had greater bone repairing ability than chitin alone. Conclusion: Chitin may be used as a bone substitute material and carrier of BMP. But its mechanical strength and surface activity should be improved.

BACKGROUNDCytochrome b5 reductase 2 (CYB5R2) is a potential tumor suppressor that inhibits cell proliferation and motility in nasopharyngeal carcinoma (NPC). Inactivation of CYB5R2 is associated with lymph node metastasis in NPC. This study aimed to explore the mechanisms contributing to the anti-neoplastic effects of CYB5R2.

METHODSPolymerase chain reaction (PCR) assays were used to analyze the transcription of 84 genes known to be involved in representative cancer pathways in the NPC cell line HONE1. NPC cell lines CNE2 and HONE1 were transiently transfected with CYB5R2, and data was validated by real-time PCR. A chick chorioallantoic membrane (CAM) embryo model was implanted with CYB5R2-expressing CNE2 and HONE1 cells to evaluate the effect of CYB5R2 on angiogenesis. An immunohistochemical assay of the CAM model was used to analyze the protein expression of vascular endothelial growth factor (VEGF).

RESULTSIn CYB5R2-transfected NPC cells, PCR assays revealed up-regulated mRNA levels of Fas cell surface death receptor (FAS), FBJ murine osteosarcoma viral oncogene homolog (FOS), phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), integrin beta 3 (ITGB3), metastasis suppressor 1 (MTSS1), interferon beta 1 (IFNB1), and cyclin-dependent kinase inhibitor 2A (CDKN2A) and down-regulated levels of integrin beta 5 (ITGB5), insulin-like growth factor 1 (IGF1), TEK tyrosine kinase (TEK), transforming growth factor beta receptor 1 (TGFBR1), and VEGF. The angiogenesis in the CAM model implanted with CYB5R2-transfected NPC cells was inhibited. Down-regulation of VEGF by CYB5R2 in NPC cells was confirmed by immunohistochemical staining in the CAM model.

CONCLUSIONCYB5R2 up-regulates the expression of genes that negatively modulate angiogenesis in NPC cells and down-regulates the expression of VEGF to reduce angiogenesis, thereby suppressing tumor formation.

Animals ; Carcinoma ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Chickens ; Cytochrome-B(5) Reductase ; Down-Regulation ; Gene Regulatory Networks ; Genes, Tumor Suppressor ; Humans ; Nasopharyngeal Neoplasms ; Neovascularization, Pathologic ; Oxidoreductases ; Real-Time Polymerase Chain Reaction ; Transfection ; Up-Regulation ; Vascular Endothelial Growth Factor A