Loss of RUNX3 expression is suggested to be causally related to gastric cancer as 45% to 60% of gastric cancers do not express RUNX3 mainly due to hypermethylation of the RUNX3 promoter. Here, we examined for other defects in the properties of RUNX3 in gastric cancers that express RUNX3. Ninety-seven gastric cancer tumor specimens and 21 gastric cancer cell lines were examined by immunohistochemistry using novel anti-RUNX3 monoclonal antibodies. In normal gastric mucosa, RUNX3 was expressed most strongly in the nuclei of chief cells as well as in surface epithelial cells. In chief cells, a significant portion of the protein was also found in the cytoplasm. RUNX3 was not detectable in 43 of 97 (44%) cases of gastric cancers tested and a further 38% showed exclusive cytoplasmic localization, whereas only 18% showed nuclear localization. Evidence is presented suggesting that transforming growth factor-B is an inducer of nuclear translocation of RUNX3, and RUNX3 in the cytoplasm of cancer cells is inactive as a tumor suppressor. RUNX3 was found to be inactive in 82% of gastric cancers through either gene silencing or protein mislocalization to the cytoplasm. In addition to the deregulation of mechanisms controlling gene expression, there would also seem to be at least one other mechanism controlling nuclear translocation of RUNX3 that is impaired frequently in gastric cancer. (Cancer Res 2005; 65(17): 7743-50)

Connective tissue growth factor (CTGF) plays a critical role in keloid pathogenesis by promoting collagen synthesis and deposition. Previous work suggested epithelial-mesenchymal interactions as a plausible factor affecting the expression of various growth factors and cytokines by both the epithelial and dermal mesenchymal cells. The aim of this study is to explore the role of epithelial-mesenchymal interactions in modulating CTGF expression. Immunohistochemistry was employed to check CTGF localization in skin tissue. Western blot assay was performed on total protein extracts from skin tissue, cell lysates and conditioned media to detect the basal/expression levels of CTGF. Study groups were subjected to serum stimulation (fibroblast-single cell culture) and pharmacological inhibitors targeted against mTOR (Rapamycin), Sp1 (WP631 and Mitoxanthrone), Smad3 (SB431542), and PI3K (LY294002). Increased localization of CTGF in the basal layer of keloid epidermis and higher expression of CTGF was observed in the keloid tissue extract. Interestingly, lower basal levels of CTGF was observed in fibroblast cell lysates cocultured with keloid keratinocytes compared to normal keratinocytes, while the conditioned media from the former culture consistently demonstrated a higher expression of secreted CTGF as compared to the latter group. These results demonstrate an important role of epithelial-mesenchymal interactions in the regulation of CTGF expression. Fibroblasts treated with inhibitors against mTOR, Sp1, Smad3, and PI3K demonstrated a reduced expression of CTGF, suggesting these signaling pathways to be important in the regulation of CTGF expression. Thus, revealing the therapeutic potentials for inhibitors that are selective for these factors in controlling CTGF expression in fibrotic conditions.

Surface modifications of Ar plasma-pretreated poly(tetrafluoroethylene) (PTFE) film via UV light-induced graft copolymerization with 1-vinylimidazole (VIDz) and glycidyl methacrylate (GMA) were carried out to improve the adhesion with evaporated copper. The surface compositions of the graft-copolymerized PTFE films were studied by X-ray photoelectron spectroscopy (XPS). The graft yield increases with the monomer concentration. The adhesion strength of the graft-copolymerized PTFE film and the evaporated copper is affected by the type of monomer used for graft copolymerization, the graft concentration, the plasma posttreatment time after graft copolymerization, and the extent of heat posttreatment after evaporation of copper. A double graft copolymerization process, which involved first the graft copolymerization with VIDz, followed by graft copolymerization with GMA, was also employed to enhance the adhesion of evaporated Cu to PTFE. The T-type peel strength of the PTFE/Cu interface so obtained is about 15 N/cm, which represents a 10-fold increase over that obtained when the PTFE film was treated by plasma only. The mechanism of the peel strength enhancement and the cohesive failure of the polymer−metal interface were also investigated.

Basal cell carcinomas (BCC), which are the most common form of skin malignancy, are invariably associated with the deregulation of the Sonic Hedgehog (Shh) signalling pathway. As such, BCC represent a unique model for the study of interactions of the Shh pathway with other genes and pathways. We constructed a tissue microarray (TMA) of 75 paired BCC and normal skin and analysed the expression of b-catenin and RUNX3, nuclear effectors of the wingless-Int (Wnt) and bone morphogenetic protein/ transforming growth factor-b pathways, respectively. In line with previous reports, we observed varying subcellular expression pattern of b-catenin in BCC, with 31 cases (41%) showing nuclear accumulation. In contrast, all the BCC cases tested by the TMA showed RUNX3 protein uniformly overexpressed in the nuclei of the cancer cells. Analysis by Western blotting and DNA sequencing indicates that the overexpressed protein is normal and full-length, containing no mutation in the coding region, implicating RUNX3 as an oncogene in certain human cancers. Our results indicate that although the deregulation of Wnt signalling could contribute to the pathogenesis of a subset of BCC, RUNX3 appears to be a universal downstream mediator of a constitutively active Shh pathway in BCC.