Figure 1

Expression of VHL inhibits collagen invasion and degradation. A. Collagen invasion. WT8 and pRc-9 cells were cultured in serum-free media on top of type I collagen coated membranes in a Transwell^® invasion assay system. The lower chambers contained either serum-free DMEM as a negative control or DMEM supplemented with 10% FBS as a chemoattractant. At time of harvest, the non-invaded cells and collagen matrix on top of the membranes were removed, and invaded cells on the bottoms of the membranes were stained with methylene blue. A representative picture is shown of cells invading towards serum-free versus serum-containing media. Cells were counted from 3 fields per sample at 100× and averaged. Values in the graph represent the average number of cells invaded towards serum from four separate experiments relative to WT8 cell invasion (mean+/-S.D.); P < 0.05 (*). B. Collagen degradation. WT8 and pRc-9 cells were serum-starved overnight, harvested and then embedded in a mixture of type I collagen and serum-free DMEM for the collagen degradation assay. The collagen gel was allowed to solidify and serum-free media was added to the top of the collagen gel. The overlying media was weighed 48 hours after time of plating, and collagen degradation was determined by the volume of media liberated from the collagen gel. Values represent the average μL of media released from three samples (mean+/-S.D.); P < 0.01 (*) and are representative of four separate experiments. Statistical analyses were performed using the student's t-test.