Nonsteroidal antiinflammatories are known to suppress incidence and progression of malignancies including colorectal cancers. However, the precise mechanism of this action remains unknown. Using prostaglandin (PG) receptor knockout mice, we have evaluated a role of PGs in tumor-associated angiogenesis and tumor growth, and identified PG receptors involved. Sarcoma-180 cells implanted in wild-type (WT) mice formed a tumor with extensive angiogenesis, which was greatly suppressed by specific inhibitors for cyclooxygenase (COX)-2 but not for COX-1. Angiogenesis in sponge implantation model, which can mimic tumor-stromal angiogenesis, was markedly suppressed in mice lacking EP3 (EP3−/−) with reduced expression of vascular endothelial growth factor (VEGF) around the sponge implants. Further, implanted tumor growth (sarcoma-180, Lewis lung carcinoma) was markedly suppressed in EP3−/−, in which tumor-associated angiogenesis was also reduced. Immunohistochemical analysis revealed that major VEGF-expressing cells in the stroma were CD3/Mac-1 double-negative fibroblasts, and that VEGF-expression in the stroma was markedly reduced in EP3−/−, compared with WT. Application of an EP3 receptor antagonist inhibited tumor growth and angiogenesis in WT, but not in EP3−/−. These results demonstrate significance of host stromal PGE2-EP3 receptor signaling in tumor development and angiogenesis. An EP3 receptor antagonist may be a candidate of chemopreventive agents effective for malignant tumors.

Formation of coated carrier vesicles, such as COPIcoated vesicles from the cis-Golgi, is triggered by membrane binding of the GTP-bound form of ADP-ribosylation factors. This process is blocked by brefeldin A, which is an inhibitor of guanine nucleotide exchange factors for ADP-ribosylation factor. GBF1 is one of the guanine nucleotide-exchange factors for ADPribosylation factor and is localized in the Golgi region. In the present study, we have determined the detailed subcellular localization of GBF1. Immunofluorescence microscopy of cells treated with nocodazole or incubated at 15 aeC has suggested that GBF1 behaves similarly to proteins recycling between the cis-Golgi and the endoplasmic reticulum. Immunoelectron microscopy has revealed that GBF1 localizes primarily to vesicular and tubular structures apposed to the cisface of Golgi stacks and minor fractions to the Golgi stacks. GBF1 overexpressed in cells causes recruitment of class I and class II ADP-ribosylation factors onto Golgi membranes. Furthermore, overexpressed GBF1 antagonizes various effects of brefeldin A, such as inhibition of membrane recruitment of ADP-ribosylation factors and the COPI coat, and redistribution of Golgi-resident and itinerant proteins. These observations indicate that GBF1 is involved in the formation of COPI-coated vesicles from the cis-Golgi or the preGolgi intermediate compartment through activating ADP-ribosylation factors.

No abstract

Pooled analyses of independent cohort studies confirmed the long-term prognostic value of cardiac mIBG uptake in patients with HF independently of other markers, such as NYHA functional class, BNP, and LVEF, and demonstrated that categoric assessments could be used to define meaningful thresholds for lethal event risk.

Angiogenesis is reportedly enhanced by prostaglandins (PGs). In the present study, we investigated whether or not cyclo‐oxygenase (COX)‐2 mediated angiogenesis in chronic and proliferate granuloma. In rat sponge implants, angiogenesis was gradually developed over a 14‐day experimental period as granuloma formed. This angiogenesis was enhanced by topical injections of human recombinant basic fibroblast growth factor (bFGF). In sponge granuloma, mRNA of COX‐1 was constitutively expressed, whereas that of COX‐2 was increased with neovascularization in parallel with that of vascular endothelial growth factor (VEGF). Topical injections of bFGF increased the expression of COX‐2 mRNA. bFGF‐stimulated angiogenesis was inhibited by indomethacin or selective COX‐2 inhibitors, NS‐398, nimesulide, and JTE‐522. The levels of PGE2 and 6‐keto‐PGF1α in the sponge granuloma were increased with bFGF 13 fold and 9 fold, respectively, and these levels were markedly reduced by NS‐398. The expression of VEGF mRNA in the granuloma was also enhanced by bFGF, and was reduced by NS‐398. Topical injections of PGE2 and beraprost sodium, a PGI2 analogue, increased the expression of VEGF mRNA, with angiogenesis enhancement. The enhanced angiogenesis by bFGF was significantly inhibited by topical injections of VEGF anti‐sense oligonucleotide. These results suggested that COX‐2 may enhance bFGF‐induced neovascularization in sponge granuloma by PG‐mediated expression of VEGF, and that a COX‐2 inhibitor would facilitate the management of conditions involving angiogenesis. British Journal of Pharmacology (2000) 130, 641–649; doi:

No abstract

Extracellular matrix (ECM), which provides critical scaffolds for all adhesive cells, regulates proliferation, differentiation, and apoptosis. Different cell types employ customized ECMs, which are thought to play important roles in the generation of so-called niches that contribute to cell-specific functions. The molecular entities of these customized ECMs, however, have not been elucidated. Here, we describe a strategy for transcriptome-wide identification of ECM proteins based on computational screening of >60,000 full-length mouse cDNAs for secreted proteins, followed by in vitro functional assays. These assays screened the candidate proteins for ECM-assembling activities, interactions with other ECM molecules, modifications with glycosaminoglycans, and cell-adhesive activities, and were then complemented with immunohistochemical analysis. We identified 16 ECM proteins, of which seven were localized in basement membrane (BM) zones. The identification of these previously unknown BM proteins allowed us to construct a body map of BM proteins, which represents the comprehensive immunohistochemistry-based expression profiles of the tissue-specific customization of BMs. basement membrane ͉ body map ͉ niche ͉ cell adhesion ͉ glycosaminoglycan

Angiotensin II is a multi-functional bioactive peptide and recent reports have suggested that angiotensin II is a proangiogenic growth factor. A retrospective cohort study revealed that angiotensin converting enzyme inhibitors decreased cancer risk, however, the precise mechanism is unknown. We hypothesized that endogenous angiotensin II plays a crucial role in tumor-associated angiogenesis. Tumors implanted in the subcutaneous tissue of wild-type mice developed intensive angiogenesis with vascular endothelial growth factor (VEGF) induction in tumor stroma. AT1a receptor (AT1a-R), but not AT1b receptor or AT2 receptor was expressed in tumor stroma and systemic administration of an AT1-R antagonist reduced tumor-associated angiogenesis and VEGF expression in tumor stroma. Angiotensin II up-regulates VEGF expression through the pathway including protein kinase C, AP-1 and NF-kappaB in fibroblasts, the major cellular component of tumor stroma. VEGF is a major determinant of tumor-associated angiogenesis in the present model, since angiogenesis was markedly reduced by either a VEGF neutralizing antibody or a VEGF receptor kinase inhibitor. Compared with the wild-type, tumor-associated angiogenesis was reduced in AT1a-R null mice, with reduced expression of VEGF in the stroma, and this reduction in AT1a-R null mice was not inhibited by an AT1-R antagonist. These suggest that host stromal VEGF induction by AT1a-R signaling is a key regulator of tumor-associated angiogenesis and tumor growth. AT1a-R signaling blockade may be a novel and effective therapeutic strategy against cancers.