Membrane association of collagenase stimulatory factor(s) from B-16 melanoma cells

✍ Scribed by Chitra Biswas; Matthew A. Nugent

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 768 KB
• Volume: 35
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240350307

✦ Synopsis

Past studies have shown that contact between tumor cells and fibroblasts results in stimulation of collagenase production by the fibroblasts. Membrane fractions prepared by differential centrifugation of sonicated B-16 melanoma cells were shown here to contain a collagenase stimulatory factor(s) (CSF). Trypsin treatment of intact B-16 cells prior to membrane fractionation led to loss of 90% of the total activity, indicating that CSF is localized on the outer surface of the cells. Stimulation of fibroblast collegenase production was also observed with dialyzed octylglucoside extracts of the B-16 membranes. Additional of exogeneous lipid, ie, a mixture of phosphatidylcholine and phosphatidylserine, to the detergent extract of the membranes followed by dialysis and centrifugation at 100,OOOg resulted in 80% recovery of the factor activity in the pellet containing reconstituted lipid vesicles. Fractionation of tritium-labeled, reconstituted lipid vesicles on a Sephacryl S-300 column revealed that the collagenase stimulatory factor coeluted with the radioactive lipid vesicles. The fractionated lipid vesicles lost stimulatory activity completely after trypsin treatment or heating at 65"C, indicating that the factor is a protein.