Overexpression of lysosomal-type sialidase leads to suppression of metastasis associated with reversion of malignant phenotype in murine B16 melanoma cells.
Increased sialylation in cell surface glycoproteins is one characteristic feature of cancer cells, particularly related to their metastatic potential and invasiveness. Expression of lysosomal-type sialidase, which plays a major role in hydrolysis of such sialo-glycoproteins, is therefore considered to have a great influence on malignant properties of cancer cells. To investigate whether the sialidase expression level is linked to the malignant phenotype, we transfected B16-BL6 murine melanoma cells, a highly invasive and metastatic line, with an expression vector harboring a rat lysosomal sialidase cDNA; then clones were isolated and examined for changes in biological character. Sialidase-overexpressing cells showed suppression of experimental pulmonary metastasis and tumor progression. The transfectants exhibited diminished cell growth, anchorage-independent growth and increased sensitivity to apoptosis induced by suspension culture or serum depletion in vitro, but no significant alterations in invasiveness, cell motility and cell attachment to fibronectin, collagen IV and laminin. Flow cytometric analysis with either peanut agglutinin (PNA) or Ricinus communis agglutinin (RCA) lectin revealed that desialylated forms of glycoproteins on the cell surfaces were increased. In particular, a desialylated form of a cell surface glycoprotein of 83 kDa was prominent in the transfectants, as determined by galactose oxidase labeling. These observations indicate that sialidase expression is inversely associated with metastatic potential and tumor growth in cancer cells, probably through a regulation mechanism that suppresses cell growth and anchorage-independent growth and promotes apoptosis with deprivation of cell anchorage.
Kato
T
T
Division of Biochemistry, Research Institute, Miyagi Prefectural Cancer Center, Natori, Miyagi, Japan.
Wang
Y
Y
Yamaguchi
K
K
Milner
C M
CM
Shineha
R
R
Satomi
S
S
Miyagi
T
T
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002448:Cell Adhesion; D002455:Cell Division; D002465:Cell Movement; D003094:Collagen / Q000378:metabolism; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005353:Fibronectins / Q000378:metabolism; D005434:Flow Cytometry; D005692:Galactose Oxidase / Q000378:metabolism; D005822:Genetic Vectors; D006023:Glycoproteins / Q000378:metabolism; D007797:Laminin / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D008175:Lung Neoplasms / Q000556:secondary; D008247:Lysosomes / Q000201:enzymology*; D008546:Melanoma, Experimental; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009439:Neuraminidase / Q000096:biosynthesis* / Q000235:genetics*; D010641:Phenotype; D011102:Polyhydroxyethyl Methacrylate / Q000378:metabolism; D011233:Precipitin Tests; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
D016895:Culture Media, Serum-Free; D018076:DNA, Complementary; D005353:Fibronectins; D006023:Glycoproteins; D007797:Laminin; D037102:Lectins; D011102:Polyhydroxyethyl Methacrylate; D003094:Collagen; D005692:Galactose Oxidase; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid