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Query: UNIPROT:Q9UIJ5 (
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58,342
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The ability of PGE2 to stimulate bone resorption in vitro and in vivo is well established but the effects of this compound on bone formation are still controversial. Recent clinical reports have suggested that long-term infusion of
PGE
in infants with cyanotic heart diseases led to a stimulation of periosteal bone formation and to hyperostosis. In the present report, we describe the effects of PGE2 (10(-5) M) in bone organ cultures on bone resorption, measured by the release of 45Calcium and the number of osteoclasts in sections of cultured bones, and bone volume, by measuring separately medullary and cortical areas. PGE2 induced a marked increase in 45Ca release and in cortical and medullary osteoclast numbers over 4 days in vitro; despite this increase in bone resorption, cortical bone volume remained constant, indicating a parallel increase in bone resorption and formation at this site. Morphological and quantitative data demonstrated a higher extent of osteoblastic surface along the periosteum of PGE2-treated bones when compared with control cultures. Medullary bone volume, on the other hand, decreased sharply during the culture period, demonstrating a lack of parallel increase in bone formation at this site. It is concluded that, under these experimental conditions, prostaglandin E2 stimulated both resorption and formation along the periosteum and only bone resorption along the endosteum of the cultured bones. The overall effect of PGE2 on bone as a whole, however, was net bone loss.
Anat
Rec
1985 Jan
PMID:PGE2 stimulates both resorption and formation of bone in vitro: differential responses of the periosteum and the endosteum in fetal rat long bone cultures. 398 83
Most experimental work addressing cyclooxygenase-2 (COX-2) inhibitor has focused on suppressing hematogenic spread. Little is known about the mechanism by which this inhibitor can also block lymphatic metastasis. Here, the effects of COX-2 inhibitor on vascular endothelial growth factor-C (VEGF-C) expression, lymphangiogenesis and lymph node metastasis were investigated. Utilizing the highly metastatic human lung adenocarcinoma cell line Anip973 and its parental line AGZY83-a, which has a low metastatic capacity, we found elevated VEGF-C and COX-2 immunoreactivity in Anip973 cells compared with AGZY83-a cells. Celecoxib down-regulated expression of VEGF-C mRNA and protein in Anip973 cells while
PGE
(2) up-regulated expression of VEGF-C mRNA and protein in AGZY83-a cells in a concentration-dependent manner. The expression of COX-2 and VEGF-C was significantly increased in xenografted Anip973 tumors compared with AGZY83-a tumors. The Anip973 tumors showed more lymphatic vessels and lymph node metastasis than the AGZY83-a tumors. In vivo, celecoxib decreased VEGF-C expression in Anip973 tumor-treated mice to a similar level to that in the AGZY83-a tumor-treated mice. Consistent with this decrease in VEGF-C expression, the density of lymphatic vessels and lymph node metastasis in Anip973 tumor-treated mice were suppressed to approximately that found in the AGZY83-a tumor-treated ones. Taken together, our results suggest that the differential expression of COX-2 and VEGF-C might help explain the different metastasis phenotype of lung adenocarcinoma cancer, and that COX-2 inhibitor mediates VEGF-C to block lymphangiogenesis and lymph node metastasis. Thus, COX-2 may be a potential therapeutic target for blocking lymph node metastasis in lung adenocarcinoma.
Anat
Rec
(Hoboken) 2009 Oct
PMID:Inhibition of cyclooxygenase-2 suppresses lymph node metastasis via VEGF-C. 1968 8
The mechanisms underlying the effects of COX-2 on tumor lymphangiogenesis remain largely undefined. Here, the human lung cancer cell lines A549, 95D, Anip973, and AGZY83-a with different metastatic capacities were investigated by immunostaining, western blotting, and real-time RT-PCR. We observed increased expressions of COX-2 and VEGF-C in the three highly metastatic cell lines compared with the less metastatic AGZY83-a cell line. The COX-2-specific inhibitor Celecoxib suppressed VEGF-C expression whereas the main COX-2 metabolite
PGE
(2) elevated VEGF-C expression in Anip973 and AGZY83-a cells in positive and negative experiments. To determine the functional link to COX-2 more specifically and elucidate the mechanistic pathway, we used a siRNA to knock down the high COX-2 expression in Anip973 cells and transfected a COX-2 cDNA to enhance the low COX-2 expression in AGZY83-a cells, and then treated the cells with EP1/EP4 agonists or antagonists, respectively. The results revealed that the EP1/EP4 agonists significantly increased VEGF-C production in the COX-2-knockdown Anip973 cells. In contrast, the EP1/EP4 antagonists diminished VEGF-C production in the COX-2-overexpressing AGZY83-a cells. Furthermore, animal models provided evidence that Celecoxib decreased VEGF-C expression, lymphangiogenesis, and lymph node metastases in Anip973 cells, whereas
PGE
(2) treatment increased the same factors in the parental AGZY83-a cells. A positive correlation between COX-2 and VEGF-C was also confirmed in vivo. The present data suggest that COX-2 regulates VEGF-C expression via the
PGE
(2) pathway, and that EP1/EP4 receptors are involved in
PGE
(2)-mediated VEGF-C production. Thus, COX-2 may represent a candidate gene for blocking tumor lymphangiogenesis and lymph node metastasis.
Anat
Rec
(Hoboken) 2010 Nov
PMID:COX-2-mediated regulation of VEGF-C in association with lymphangiogenesis and lymph node metastasis in lung cancer. 2083 Jul 83