Maspin: a tumor suppressing serpin.
Maspin, a serpin found in mammary epithelial cells, has been shown to have tumor suppressor activity. The gene is expressed in normal human mammary epithelial cells but down-regulated in invasive breast carcinomas. Similar patterns of expression at the RNA and protein levels are seen by Northern analysis with cells grown in culture and by immunostaining of tissues. Biological assays of invasion by tumor cells through matrigel membranes and of motility have shown that recombinant maspin inhibits both processes, and that its inhibitory action is totally lost by a single cleavage at the reaction center. Tumor transfectants expressing maspin are inhibited in growth and invasion in nude mice. Maspin is located in the cell membrane and extracellular matrix, and does not behave as a classical inhibitory serpin against any known target protease. Its mode of action is presently unknown.
Sager
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R
Department of Cancer Genetics, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Sheng
S
S
Pemberton
P
P
Hendrix
M J
MJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002465:Cell Movement; D003001:Cloning, Molecular / Q000379:methods; D005260:Female; D016147:Genes, Tumor Suppressor; D015316:Genetic Therapy; D006801:Humans; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000502:physiology; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000473:pathology; D011506:Proteins / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D011817:Rabbits; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015843:Serpins / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured
D009363:Neoplasm Proteins; D011506:Proteins; D011994:Recombinant Proteins; C085344:SERPIN-B5; D015843:Serpins