SMYD3 promotes implant metastasis of ovarian cancer via H3K4 trimethylation of integrin promoters

Detachment of cancer cells from the primary tumor and formation of spheroids in ascites is required for implantation metastasis in epithelial ovarian cancer (EOC), but the underlying mechanism of this process has not been thoroughly elucidated. To mimic this process, ovarian cancer cells were grown in 3D and 2D culture. Hey and OVCA433 spheroids exhibited decreased cell proliferation and enhanced adhesion and invasion. SMYD3 expression was elevated in ovarian carcinoma spheroids in association with increased H3K4 methylation. Depletion of SMYD3 by transient siRNA, stable shRNA knockdown and the SMYD3 inhibitor BCI-121 all decreased spheroid invasion and adhesion. Gene expression arrays revealed downregulation of integrin family members. Inhibition assays confirmed that invasion and adhesion of spheroids are mediated by ITGB6 and ITGAM. SMYD3-deficient cells regained the ability to invade and adhere after forced overexpression of SMYD3, ITGB6 and ITGAM. However, this biological ability was not restored by forced overexpression of SMYD3 in ITGB6- and/or ITGAM-deficient cancer cells. SMYD3 and H3K4me3 binding at the ITGB6 and ITGAM promoters was increased in spheroids compared to that in monolayer cells, and the binding was decreased when SMYD3 expression was inhibited, consistent with the expression changes in integrins. SMYD3 expression and integrin-mediated adhesion were also activated in an intraperitoneal xenograft model and in EOC patient spheroids. In vivo, SMYD3 knockdown inhibited tumor metastasis and reduced ascites volume in both the intraperitoneal xenograft model and a PDX model. Overall, our results suggest that the SMYD3-H3K4me3-integrin pathway plays a crucial role in ovarian cancer metastasis to the peritoneal surface.     

In silico analysis‐based identification of the target residue of integrin α6 for metastasis inhibition of basal‐like breast cancer

Metastasis causes death in breast cancer patients. To inhibit breast cancer metastasis, we focused on integrin α6, a membrane protein that contributes to cell migration and metastasis. According to in silico analysis, we identified Asp‐358 as an integrin α6‐specific vertebrate‐conserved residue and consequently as a potential therapeutic target. Because Asp‐358 is located on the surface of the β propeller domain that interacts with other molecules for integrin α6 function, we hypothesized that a peptide with the sequence around Asp‐358 competitively inhibits integrin α6 complex formation. We treated basal‐like breast cancer cells with the peptide and observed reductions in cell migration and metastasis. The result of the immunoprecipitation assay showed that the peptide inhibited integrin α6 complex formation. Our immunofluorescence for phosphorylated paxillin, a marker of integrin‐regulated focal adhesion, showed that the peptide reduced the number of focal adhesions. These results indicate that the peptide inhibits integrin α6 function. This study identified the functional residue of integrin α6 and designed the inhibitory peptide. For breast cancer patients, metastasis inhibition therapy may be developed in the future based on this study.     

RGD类肽抑制高转移舌癌细胞粘附、迁移的实验研究

目的　进行合成肽RGDS(精氨酸 甘氨酸 天冬氨酸 丝氨酸 )抑制脑转移舌癌细胞转移机理方面的研究。方法　采用MTT法研究不同浓度的RGDS对Tb细胞粘附人工重组基底膜 (Matrigel)及纤维连接蛋白 (Fn)能力的影响 :细胞移动实验测定RGDS抑制Tb细胞在Matrigel及Fn上迁移的能力 ;明胶底物SDS PAGE电泳推测RGDS与基质金属蛋白酶的关系。结果　不同浓度的RGDS抑制了Tb细胞对Matrigel及Fn的粘附 ,并能抑制Tb细胞在Matrigel及Fn上的迁移。电泳结果表明RGDS能部分抑制由Fn诱导的基质金属蛋白酶的分泌。 结论　RGDS能抑制Tb细胞的粘附、迁移及抑制由Fn诱导的金属蛋白酶分泌 ,提示RGDS有抗肿瘤转移活性。     

种植体表面修饰影响骨结合机制研究进展

<正>钛及其合金具有化学稳定性高,弹性模量等力学性能与骨组织比较匹配等优点,是广泛应用的人体硬组织修复材料。钛及其合金本质上是生物惰性     

Expression of the cutaneous lymphocyte antigen and the αβ7 integrin by intraepithelial lymphocytes in healthy and diseased human gingiva

The presence of specific phenotypes of intraepithelial lymphocytes (IEL) was determined in healthy and diseased gingiva by immunohistochemistry. The cutaneous lymphocyte antigen (CLA) and the α^IELβ₇ integrin were detected with the HECA-452 and with the HML-1 monoclonal antibodies, respectively. Some 24–62% of CD3-positive intraepithelial lymphocytes expressed the CLA antigen in the junctional epithelium, while 49–54% expressed the α^IELβ₇ integrin. Similar results were obtained in the other gingival epithelia. The fraction of CLA-positive T cells and α^IELβ₇ integrin-positive T cells was significantly higher in the gingival epithelia than in the underlying connective tissue, indicating that the T-cell subsets defined by these surface adhesion molecules were selectively localized in the epithelial compartment. Comparison of the fractions of CLA-positive and α^IELβ₇ integrin-positive T cells across different disease groups did not show significant differences. The data indicate that intraepithelial lymphocytes expressing the CLA and the α^IELβ₇ phenotype are a quantitatively important component of gingival intraepithelial immunity. These adhesion molecules may play a part in the retention of specific T-cell subsets in gingival epithelia.     

大鼠牙周炎牙正畸移动后整合素β_3mRNA变化的实验研究

目的研究大鼠牙周炎牙及其正常牙在正畸移动中整合素β3mRNA的表达变化.方法选用10周龄雄性成年SD大鼠96只,随机分为正常牙组、牙周炎牙组,每组48只.分别在加力后0 d、12 h、1 d、3 d、5 d、7 d每一时间点处死8只动物,制备标本.采用原位杂交检测牙周炎牙与正常牙正畸移动后β3mRNA转录水平的变化.结果正常牙组和牙周炎牙组加力后12 h和3 d时的牙周膜内破骨细胞整合素β3mRNA阳性强度均较加力前有明显增加(P＜0.001);其余时间点未见整合素β3mRNA阳性表达.在加力各时间点,两组整合素β3mRNA的表达强度无显著性差异(P＞0.05).结论在正常牙及牙周炎牙移动早期,牙周膜和牙槽骨骨髓腔内有整合素β3mRNA表达,提示整合素β3可能参与破骨细胞前体向破骨细胞转化及破骨细胞迁移和粘附.     

Differential localization of laminin gamma and integrin beta in primary cultures of the rat gingival epithelium

OBJECTIVES: The aim of this study was to investigate the differential immunolocalization of laminin gamma(2) and integrin beta(4) in primary cultures of the rat gingival epithelium. METHODS: The gingival epithelium was obtained from Sprague-Dawley rats and was cultured in serum-free keratinocyte growth medium (DK-SFM). Western blotting analysis, immunofluorescence, confocal laser scanning microscopy (CLSM), and immuno-gold labeling for laminin gamma(2) and integrin beta(4) were employed. CLSM images for laminin and integrin were analyzed in horizontal (x-y axis) and in vertical (x-z axis) sections. RESULTS: Both laminin gamma(2) and integrin beta(4) were detected by Western blot analysis in the gingival epithelium. Immunolocalization of laminin gamma(2) was distinct in the cytoplasm to form one or two irregular rings in gingival epithelial cells. By contrast, integrin beta(4) was localized diffusely in the cytoplasm. F-actin (indicating actin filaments) was clearly discernible at the periphery of the cytoplasm to form a cellular fringe. In x-z axis images obtained by CLSM, laminin gamma(2) was recognized as large foci in the most inner portion just above the basal plasma membrane. Integrin beta(4) existed in the area where F-actin was labeled surrounding the membrane. Immuno-electron microscopy showed that 10nm colloidal gold particles indicating laminin gamma(2) were mainly localized at the extracellular portion and in the peripheral cytoplasm, whereas integrin beta(4) was distributed in the cytoplasm close to the basal plasma membrane but not in extracellular regions. CONCLUSIONS: In primary cultures of the rat gingival epithelium, both laminin gamma(2) and integrin beta(4) may be produced by the epithelium, and irregular rings of laminin gamma(2) are formed in areas where gingival cells adhere to the extracellular matrix.