Knockdown of Sec8 promotes cell-cycle arrest at G1/S phase by inducing p21 via control of FOXO proteins.

p21(Cip1) protein inhibits the activity of cyclins at the G(1) checkpoint and influences transition of cells from the G(1) to the S phase of the cell cycle. Moreover, expression of members of the FOXO family (active form of forkhead transcription factors of the O class) in dividing cells promotes cell-cycle arrest at the G(1)/S boundary via regulation of p21(Cip1). Recently, the exocyst complex, including Sec8, has been implicated in various roles independent of its role in secretion, such as cell migration, invadopodia formation, cytokinesis, glucose uptake and neural development. Given the essential roles of the exocyst complex in cellular and developmental processes, disruption of its function may be involved in various diseases such as cancer, diabetes and neuronal disorders. However, the relationship between Sec8 and the cell cycle remains to be elucidated. In this study, knockdown of Sec8 inhibited cell growth and promoted cell-cycle arrest at the G(1)/S phase by control of p21 expression and retinoblastoma protein phosphorylation. Furthermore, Sec8 regulated FOXO family proteins via ubiquitin-proteasome degradation by regulating the expression of the murine double minute 2 (Mdm2) protein but not S-phase kinase-associated protein 2 (Skp2).

Developing a new appliance to dissipate mechanical load on teeth and improve limitation of vertical mouth.

OBJECTIVES: The principle of leverage to superpose the convex surfaces of two shells was applied to develop a device for treating limitation of mouth opening and called it the "shell-shaped mouth opener" and analyzed pressure on the teeth with the TheraBite(®) appliance and the shell-shaped mouth opening appliance. MATERIAL AND METHODS: To compare the TheraBite(®) appliance and the shell-shaped mouth opening appliance, pressure on the teeth in the dentition model with both devices was analyzed using the Inastomer(®) flexible conductive sensor. RESULTS: The load was better dispersed to each tooth in the shell-shaped mouth opening appliance in the all quadrants compared to the TheraBite(®) appliance. CONCLUSIONS: The present study revealed that the shell-shaped mouth opening appliance which was originally invented in our lab, dissipated the mechanical load on teeth more evenly than the TheraBite(®) appliance.

Tetraploidy with double t(11;18) of recurrent MALT lymphoma in buccal mucosa: a case report.

Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of an extranodal marginal zone B-cell lymphoma that accounts for about 5% to 8% of all B-cell lymphomas. It is rare for a recurrent oral MALT lymphoma to have tetraploidy with a double t(11;18) chromosomal abnormality, however. A 66-year-old Japanese woman with a swelling of the right buccal mucosa was referred to our hospital. A tumor was excised, and a pathologic diagnosis of MALT lymphoma with a t(11;18) (q21; q21) chromosome translocation was made. Two years later, swelling of the right buccal mucosa recurred, which was then excised and pathologically diagnosed as MALT lymphoma. This tumor did not have a t(11;18) (q21; q21) chromosome translocation, but exhibited tetraploidy with double t(11;18). FISH analysis revealed that the recurrent MALT lymphoma of the buccal mucosa had tetraploidy with double t(11;18). This is the first reported case of a recurrent MALT lymphoma showing tetraploidy with double t(11;18).

Knockdown of Sec6 improves cell-cell adhesion by increasing α-E-catenin in oral cancer cells.

The Sec6/8 complex is essential for specific exocytic sites on the plasma membrane and contributes to membrane growth in mammalian cells. In Madin-Darby canine kidney (MDCK) cells, E-cadherin and nectin-based adhesion complexes recruit the Sec6/8 complex to intercellular contacts. However, in cancer cells, the relationship between the Sec6/8 complex and the cell-cell adhesion proteins remains obscure. We demonstrate that the expression of α-E-catenin is increased by Sec6 siRNAs, and E-cadherin and ß-catenin localize mainly at the cell-cell contact region in HSC3 cells, which were transfected with Sec6 siRNA.

Immunohistochemical comparison of CD5, lambda, and kappa expression in primary and recurrent buccal mucosa-associated lymphoid tissue (MALT) lymphomas.

Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of extranodal marginal zone B-cell lymphoma and is a distinct subtype of non-Hodgkin's lymphoma.Primary MALT lymphomas can also occur in the oral cavity, although their appearance in this location is rare. The neoplastic cells of which MALT lymphomas are composed express B-cell antigens and show monotypic immunoglobulin expression with light-chain restriction.Although neoplastic MALT lymphoma cells do not express CD5, previous studies have shown that CD5 positive MALT lymphomas are more prone to dissemination than those that do not express CD5. Moreover, there are some reports that describe kappa- and lambda- dual light chain expression in B cell malignant neoplasms.A 66-year-old Japanese woman with swelling of the right buccal mucosa was referred to our hospital. The lesion was excised and was pathologically diagnosed as a MALT lymphoma tumor with a t(11;18)(q21;q21) chromosome translocation.Swelling of the right buccal mucosa recurred 2 years later. The recurrent tumor was then excised and pathologically diagnosed as MALT lymphoma.Immunohistochemical examination of CD5, lambda, and kappa expressions revealed that the primary tumor was positive for CD5, kappa, and lambda, but the recurrent tumor was weakly positive for CD5 and kappa.With respect to lambda positivity, the recurrent tumor showed negativity.Our study suggests that immunohistochemical expression of CD5, kappa, and lambda in oral MALT lymphoma have the risk of recurrence.We first described the recurrence of CD5 positive MALT lymphoma in the oral cavity and compared the immunohistochemical expressions of CD5, lambda, and kappa between the primary and recurrent tumors.

t (11;18)(q21;q21) chromosome translocation (A1446-M1150) of MALT lymphoma in buccal mucosa.

PURPOSE: The t(11;18)(q21;q21) chromosome translocation is frequent in gastric MALT lymphoma, but the t(11;18)(q21;q21) chromosome translocation is very rare in other sites of MALT lymphomas. We investigated the possibility that MALT lymphoma occurred in the right buccal mucosa of a 66-year-old Japanese woman who had the t(11;18)(q21;q21) chromosome translocation. METHODS: Tumor specimens were examined by light microscopy and immunohistochemistry. To investigate where the present case has API-MALT1 fusion, we used the nested PCR and FISH analysis. RESULTS: Some colonized lymphoid follicles with mantle zone were observed on low-power field, and centrocyte-like cells and monocytoid B cells were observed on high-power field. Immunohistochemical staining of the tumor was positive for bcl-2, CD20, CD79a, CD43, Lambda, Kappa and was negative for CD10, IgG, IgG4, IgM, cyclin D1, bcl-6, CK (AE1/3), Helicobacter pylori. Using the nested PCR and FISH analysis, present case had the t(11;18)(q21;q21) chromosome translocation (A1446-M1150). CONCLUSION: We report that MALT lymphoma in buccal mucosa has the t(11;18)(q21;q21) chromosome translocation (A1446-M1150) by using the nested PCR and FISH analysis. This is the first report of the t(11;18)(q21;q21) chromosome translocation (A1446-M1150) of MALT lymphoma in the oral cavity.