No abstract

No abstract

SP220K is a newly described serine proteinase which displays guanidinobenzoatase activity in its inactive form and gelatinolytic activity in its active form. SP220K expression was studied in 20 renal clear-cell carcinomas and in a series of renal oncocytomas, a rare benign tumor derived from the kidney tubule epithelium. We provide evidence that SP220K expression, as assessed by guanidinobenzoatase activity, gelatin zymography and Western blot immunodetection, was increased markedly in cancer basolateral membranes compared to kidney cortex controls, whereas no signal was detectable in basolateral membranes from the 5 renal oncocytomas studied. Cytoplasms of carcinoma cells were immunodetected consistently, whereas no expression was seen in oncocytic cells from any of the oncocytomas studied (12/12). Endothelial cells were immunodetected in all 3 tissue types. Our data favor a potential mechanistic relationship between expression of the matrix proteinase SP220K and invasive phenotype in kidney epithelium proliferative processes. Int.

Matrix proteinases play a critical role in extracellular matrix remodeling, which is particularly involved in cancer invasion and metastasis. We have previously characterized and purified a new tetrameric serine proteinase (SP220K) from human kidney clear cell carcinoma plasma membranes. Here, we report that SP220K exhibits gelatinase activity as assessed both in solution and by zymography. Optimum gelatinase activity ranges between pH 7.5 to pH 9.0. Fibronectin and type I collagen were hydrolyzed by SP220K, at variance with laminin and type IV collagen. Like other trypsin‐like fibronectin degrading proteinases, SP220K released the 29‐kDa N‐terminal heparin‐binding domain of fibronectin. By using a panel of proteinase inhibitors, we found that the inhibition profile of SP220K was different from that of other known serine proteinases such as thrombin, trypsin, plasmin, plasminogen activators and tryptase. Altogether, our results indicate that SP220K corresponds to a novel matrix proteinase that exhibits a marked specificity for fibronectin and type I collagen. Int. J. Cancer 77:264–270, 1998.© 1998 Wiley‐Liss, Inc.

SP220K is a newly described serine proteinase which displays guanidinobenzoatase activity in its inactive form and gelatinolytic activity in its active form. SP220K expression was studied in 20 renal clear‐cell carcinomas and in a series of renal oncocytomas, a rare benign tumor derived from the kidney tubule epithelium. We provide evidence that SP220K expression, as assessed by guanidinobenzoatase activity, gelatin zymography and Western blot immunodetection, was increased markedly in cancer basolateral membranes compared to kidney cortex controls, whereas no signal was detectable in basolateral membranes from the 5 renal oncocytomas studied. Cytoplasms of carcinoma cells were immunodetected consistently, whereas no expression was seen in oncocytic cells from any of the oncocytomas studied (12/12). Endothelial cells were immunodetected in all 3 tissue types. Our data favor a potential mechanistic relationship between expression of the matrix proteinase SP220K and invasive phenotype in kidney epithelium proliferative processes. Int. J. Cancer 72:752–757, 1997. © 1997 Wiley‐Liss, Inc.