Dramatic changes of sulfated proteoglycans composition in a tumorigenic SV-40-transformed renal proximal-tubule cell line.
To characterize the sulfated proteoglycans (PGs) alterations associated with malignant transformation of epithelial cells in vitro, the localization, charge, size, and composition of cell-associated and secreted sulfated PGs have been compared in rabbit renal proximal-tubule cells in primary culture (Ronco et al., 1990) and in a derived SV-40 transformed cell line (RC.SV1) exhibiting a proximal phenotype and high tumor-inducing ability (Vandewalle et al., 1989). Both normal and transformed cells incorporated PGs into a thick basement membrane layer as shown by ruthenium red staining and immunodetection with a monoclonal antibody raised against the core protein of the bovine basement membrane heparan sulfate-PG (HS-PG). In primary cultures of normal cells, cell-associated PGs were almost identical to those extracted from renal tubule fractions in vivo by their size (Kav = 0.27 vs. 0.26 on Sepharose CL-6B) and composition characterized by the exclusive presence of heparan sulfate glycosaminoglycan (HS-GAG) chains. In addition, the cells secreted a HS-PG with similar biochemical characteristics (Kav = 0.29; 100% HS-GAG chains). The SV-40-transformed RC.SV1 cells also synthesized and secreted a unique PG with the same charge and Kav values and apparently the same core protein (35 kDa) as in nontransformed cells, but three major differences were observed: (i) an increased proportion of PG-associated [35S]sulfate radioactivity released into the culture medium (36 vs. 21%), (ii) the emergence of free GAG chains unincorporated into PGs and detected only in the cell-associated fraction, and (iii) a dramatic change in the composition of GAG chains in which chondroitin sulfate replaced heparan-sulfate. The latter finding is in keeping with the known chondroitin sulfate increase and heparan-sulfate decrease in epithelial tumors. The alterations of PGs observed in this study may play a role in the acquisition and/or maintenance of the malignant phenotype.
Lelongt
B
B
Institut National de la Santé et de la Recherche Médicale (INSERM), U. 64 (Hôpital Tenon, Paris), France.
Piedagnel
R
R
Châtelet
F
F
Baudouin
B
B
Brenchley
P E
PE
Verroust
P J
PJ
Cassingéna
R
R
Vandewalle
A
A
Ronco
P M
PM
D000911:Antibodies, Monoclonal; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D002850:Chromatography, Gel; D005455:Fluorescent Antibody Technique; D007124:Immunoenzyme Techniques; D007687:Kidney Tubules, Proximal / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D011509:Proteoglycans / Q000096:biosynthesis* / Q000302:isolation & purification; D013539:Simian virus 40 / Q000235:genetics*; D013431:Sulfates / Q000378:metabolism; D013462:Sulfur Radioisotopes
D000911:Antibodies, Monoclonal; D011509:Proteoglycans; D013431:Sulfates; D013462:Sulfur Radioisotopes