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Comparative study of sialidase activity and Gm3 content in B16 melanoma variants with different metastatic potential

100%

Sawada M., Moriya S., Shineha R., Satomi S., Miyagi T.

Acta Biochimica Polonica

1998

tom 45

nr 2

We previously demonstrated that transfection of a sialidase cDNA into B16-BL6 cells, a highly metastatic and invasive cell line derived from the mouse B16 melanoma, resulted in a marked suppression of metastasis accompanied by decreased cellular content of the GM3 that is one of the target molecules of the sialidase expressed (Tokuyama et al., 1997 Int. J. Cancer, 73, 410-415). To obtain further insight into the involvement of sialidase in metastasis, we made a comparison of the levels of sialidase activity and GM3 content between B16 melanoma cell lines with low (B16-F1) and high (B16-F10 and -BL6) metastatic potential. The cells exhibited sialidase activity towards 4-methylumbelliferyl N-acetylneuraminic acid (4MU-Neu5Ac) and gangliosides at acidic pH in the particulate fractions, but not in the cytosol. The activity toward 4MU-NeuAc was significantly lower in highly metastatic cells. The activity toward gangliosides, on the other hand, varied independently of metastatic potential: B16-F10 cells with a high potential for experimental metastasis showed the lowest level and B16-BL6 cells having high invasiveness had rather a higher level of ganglioside sialidase along with a much greater GM3 synthase activity than the other two cell lines. Flow cytometric analysis with anti-GM3 antibody revealed that highly metastatic cell lines were higher in the binding affinity as compared to B16-F1 cells, B16-BL6 cells containing twice as much cellular GM3 as B16-F1 cells on thin-layer chromatography.

Glutamate exocrine dynamics augmented by plasma glutamine and the distribution of amino acid transporters of the rat pancreas

58%

Fukushima D., Doi H., Fukushima K., Katsura K., Ogawa N., Sekiguchi S., Fujimori K., Sato A., Satomi S., Ishida K., Fukushima K.

Journal of Physiology and Pharmacology

2010

tom 61

nr 3

265-271

The nutritional and physiological roles of amino acid (AA)s have been investigated for individual organs. In the current study, we focused on the dynamics of glutamate and transport systems in the pancreas. We employed original procedures to obtain rat pancreatic juice (PJ) subjected to intravenous administration of alanyl-glutamine (AG) for AA analysis. The pancreatic expressions of the transporters were evaluated by immunohistochemistry. We found that glutamate was secreted into the PJ in the basal state. The intravenous administration of AG increased the concentration and total amount of glutamate excreted into the PJ. In terms of the transport systems, L-type AA transporter (LAT1) was identified exclusively in the islet cells. Glutamate transporter 1 (GLT1), glutamate-aspartate transporter (GLAST), vesicular glutamate transporter 1 (VGUT1) and cystine/glutamic acid transporter (xCT) were found in the islet cells. xCT was identified in the duct cells as well, but was not accompanied by the expression of 4F2 heavy chain (4F2hc) staining in the islets and the acinar cells, similar to neutral AA transporter (ASCT2) or b0,+-type AA transporter 1(BAT1). Excitatory AA transporter (EAAC) was identified only in the acinar cells. Glutamate was exclusively found in the acinar cells. We revealed the novel dynamics of glutamate in the rat PJ. The glutamate secretion into the PJ was augmented by plasma glutamine, indicating the de novo metabolisms of glutamate, together with the local expression of the related transporters.

Ograniczanie wyników

1 Acta Biochimica Polonica

1 Journal of Physiology and Pharmacology

2 Satomi S.

1 Doi H.

1 Fujimori K.

1 Fukushima D.

1 Fukushima K.

1 Ishida K.

1 Katsura K.

1 Miyagi T.

1 Moriya S.

1 Ogawa N.

1 Sato A.

1 Sawada M.

1 Sekiguchi S.

1 Shineha R.

1 2010

1 1998

Wyniki wyszukiwania

Comparative study of sialidase activity and Gm3 content in B16 melanoma variants with different metastatic potential

Glutamate exocrine dynamics augmented by plasma glutamine and the distribution of amino acid transporters of the rat pancreas