MiR-105 inhibits gastric cancer cells metastasis, epithelial-mesenchymal transition by targeting SOX9.

OBJECTIVE: Gastric cancer is one of the most common gastrointestinal malignancy, which is often diagnosed at an advanced stage. MicroRNA-105 (miR-105) was downregulated and acts as a tumor suppressor in various cancers. The purpose of this study was to explore the molecular mechanisms of miR-105 and sex-determining region Y-box 9 (SOX9) in gastric cancer. PATIENTS AND METHODS: Western blot was performed to display the protein level of E-Cadherin, N-Cadherin, Vimentin and SOX9. Transwell assay was utilized to measure the capacity of migration and invasion. We employed the Luciferase reporter assay to determine miR-105 targeting to SOX9 in gastric cancer. RESULTS: MiR-105 was downregulated in gastric cancer tissues and cells; it suppressed gastric cancer cell migration, invasion and epithelial-mesenchymal transition (EMT) in gastric cancer. SOX9 was upregulated in gastric cancer cells and had a negative correlation with miR-105. Moreover, the knockdown of SOX9 could inhibit gastric cancer cell migration, invasion and EMT. Furthermore, SOX9 was a target gene of miR-105 and mediated by miR-105. SOX9 could reverse the partial function of miR-105 on cell migration and invasion. In addition, miR-105 downregulation or SOX9 upregulation predicted a poor prognosis. CONCLUSIONS: We showed that miR-105 was downregulated and inhibited cell migration, invasion and EMT in gastric cancer by binding to SOX9. In addition, we demonstrated that miR-105 downregulation or SOX9 upregulation predicted a poor prognosis. The newly discoverable miR-105/SOX9 axis provides novel insight into gastric cancer treatment.

[Functional parotid surgery for removal of benign parotid tumors].

Objective: To evaluate the effect of the application of functional parotid surgery for removal of benign parotid tumors and the prevention of Frey syndrome. Method: One hundred and fifty-six cases with benign tumor were underwent functional regional parotidectomy. All tumors were smaller than 4 cm in diameter. The safe surgical margin was 5 mm when the tumors were less than 2 cm in diameter, while the safety margin was 1 cm for the tumors diameter between 2-4 cm. 156 cases were assigned to two groups(A and B). The absorbable hemostatic sponge was placed between the surface of parotid gland and skin flap after tumor resection in group A，while no sponge was placed in group B. Postoperative followup was 12-24 months. Result: No compression bandage was performed. No patient had recurrence or salivary fistula. There were 3 cases of temporary facial paralysis, of which 2 cases recovered from the mandibular marginal branch injury within 1 month and 1 case recovered from the facial nerve trunk injury within 6 months. Compared with group B 15.38%(12/78)，the incidence of Frey syndrome was significantly decreased in group A 3.85%（3/78）.χ2=5.728, P<0.05. Conclusion: The removal of benign parotid tumors by functional parotid surgery can effectively preserve the function of residual gland and reduce complication. Intraoperative implantation of absorbable hemostatic sponge between parotid gland and skin flap can reduce the incidence of Frey syndrome.

Establishment of an oral squamous cell carcinoma cell line (NOS-1) exhibiting amplification of the erbB-1 oncogene and point mutation of p53 tumor suppressor gene: its biological characteristics and animal model of local invasion by orthotopic transplantation of the cell line.

We established a new cancer cell line, NOS-1, which was derived from a human oral primary squamous cell carcinoma. Geneticin treatment was adopted to eliminate contaminating fibroblasts and to enrich tumor cells in the early stage of the culture. The NOS-1 cells showed epithelial morphological features with light and electron microscopy, and immunohistochemical analysis confirmed their epithelial origin. Overexpression of mutant p53 protein, a p53 point mutation at codon 248 with transition from CGG to TGG, and amplification of the erbB-1 oncogene/epidermal growth factor receptor gene were also observed in NOS-1 cells. The NOS-1 cells formed tumors in nude mice when transplanted subcutaneously into their backs. Further, they were transplantable orthotopically in the tongues of nude mice, and the transplanted tumors in the tongue showed diffuse invasion without forming capsules. The NOS-1 cells were useful for elucidating the mechanism involving p53 inactivation and erbB-1 oncogene amplification, as well as treatment of oral cancer.

Establishment of a novel human squamous cell carcinoma cell line from oral primary tumor by geneticin treatment.

A novel cultured cell line NOS-1, derived from a human oral primary squamous cell carcinoma (SCC) of the lower gingiva, was established without xenografting the tumor into nude mice by means of "Geneticin" treatment, which allowed for elimination of contaminated fibroblasts and produced enriched tumor cells at an early stage of the culture. NOS-1 cells showed numerous desmosome structures and some intermediate filaments. To determine tumorigenicity and to establish an orthotopic tissue invasion model for oral carcinoma, the NOS-1 cells were injected into the back and the tongue of male athymic nude mice. The back tumors showed an expansive growth pattern without significant invasion of surrounding tissues, while the tongue-implanted tumors exhibited invasive growth. The establishment of a novel oral primary tumor cell line and a new orthotopic tissue invasion model is expected to be useful for the study of biological characterization and for the identification of the invasive mechanism of human oral cancers.

Epstein-Barr virus in synergy with tumor-promoter-induced malignant transformation of immortalized human epithelial cells.

It is difficult to study how Epstein-Barr virus (EBV) causes transformation of human epithelial cells. The major difficulty is that cultured human epithelial cells do not express EBV receptor (complement receptor 2, CR2), hence EBV cannot infect such epithelial cells directly. In order to investigate the role of EBV in the transformation of human epithelial cells, pSG-CR2-Hyg carrier was transfected into immortalized human epithelial cells (293 cells) to express EBV receptor. EBV could infect these CR2-positive cells directly, and expressed EBV antigens. EBV-infected epithelial cells grew in piles with multiple cellular layers and lost contact inhibition in vitro. In soft-agar culture containing 12-0-tetradecanoylphorbol 13-acetate (TPA), EBV-infected 293 cells formed more and larger colonies. When EBV-infected 293 cells were transplanted subcutaneously into nude mice, and treated with TPA, poorly differentiated carcinoma was induced. These results suggest that EBV could induce the malignant transformation of immortalized human epithelial cells in synergy with TPA.