| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
Pancreatic cancer is known to be an extremely lethal neoplasm, main reason being that pancreatic cancer itself has an extremely high potential of invasion and metastasis. Two pancreatic cancer cell lines, the highly invasive and metastatic cell line, PC-1.0, and weakly invasive and rarely metastatic cell line, PC-1, were established from a pancreatic ductal carcinoma induced by N-nitrosobis (2-oxopropyl) amine (BGP) in a Syrian golden hamster. And highly invasive and metastatic PC-1.0 cells has been found to produce dissociation factor (DF) which induces cancer cell dissociation. The cancer cell dissociation activity in serum-free conditioned medium of PC-1.0 cells was partially purified and several biological properties of the partially purified activity were evaluated.
Two cell lines exhibited different growth morphology in vitro, the weakly invasive cell line PC-1 formed island-like colonies and the highly invasive cell line PC-1.0 grew mainly as single cells. The conditioned medium
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of PC-1.0 cells induced dissociation of island-like colonies, and morphological changes of PC-1 cells to elongated cells, with a high frequency of pseudopodia formation. The dissociation activity did not bind to the heparin column but bind to hydroxylapatite culum. and had as deduced from gel fitration. The major immunoreactive proteinous band with an apparent molecular mass of > 55 kDa was detected in immunoblotting analysis, using apolyclonal blocking antibody. The partially purified DF enhanced not only cell dissociation but also cell motility, cell adhesion to fibronectin, and chemoinvasion. The significant relationship between the induction of cell motility by DF and the c-fos mRNA expression was detected. The induction of cell motility of PC-1 cells by DF was significantly inhibited by cyclic AMP antagonist, PKC inhibitor (staurosporine), and antisence c-fos. Moreover, the representational difference analysis (RDA) revealed that MAP kinase kinase 2 (MEK2) was closely related to cell dissociation induced by DF.
These results indicate that the activation of MEK2, cyclic AMP dependent PKC and c-fos are possibly involved in the mechanism of the induction of cell dissociation and cell motility. Analysis of this factor could provide the important information to clarify the mechanism of invasion and metastasis and to develop newly therapeutic method for panreatic cancer. Less
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