Inhibition of B16 melanoma metastasis by overexpression of the cysteine proteinase inhibitor cystatin C.
Progression to metastasis has been correlated with increased cysteine proteinase activity for a number of tumour types. One mechanism of cysteine proteinase regulation in normal cells is by natural protease inhibitors, the cystatins. Here we further characterize a transfected cell line showing increased cystatin C transcription driven by cytomegalovirus (CMV) promoter/enhancer sequences. Properties of this cystatin C altered cell line such as growth in vitro, lung colonization after tail vein injection in mice, production of cystatin, and cysteine proteinase inhibitor activities were examined. Although there was no difference between the growth rate of the cystatin transfected cell line and that of the control, there was a substantial difference in metastatic ability. No increase was noted in cystatin C secretion into the media for the cystatin C transfected cell line compared with the control transfected cell line. There was, however, a difference in cysteine protease inhibitor activity in the cell-free extracts. These results show that alteration of cystatin C levels by overexpression in B16 melanoma alters properties associated with metastasis.
Cox
J L
JL
Department of Biochemistry, Kirksville College of Osteopathic Medicine, MO 63501, USA.
Sexton
P S
PS
Green
T J
TJ
Darmani
N A
NA
D000818:Animals; D015153:Blotting, Western; D002455:Cell Division / Q000235:genetics; D002999:Clone Cells; D055316:Cystatin C; D015891:Cystatins / Q000096:biosynthesis* / Q000235:genetics; D015853:Cysteine Proteinase Inhibitors / Q000096:biosynthesis* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D008175:Lung Neoplasms / Q000235:genetics / Q000556:secondary*; D008546:Melanoma, Experimental / Q000235:genetics / Q000378:metabolism* / Q000556:secondary*; D051379:Mice; D009368:Neoplasm Transplantation; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013696:Temperature; D013879:Thioredoxins / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured
C525031:Cst3 protein, mouse; D055316:Cystatin C; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D011993:Recombinant Fusion Proteins; D013879:Thioredoxins