Table 2.

N-CAM inhibits proliferation of glioma and neuroblastoma cells and fibroblasts

Cell type	Media	Reagent	Concentration	[3H]thymidine incorporation, % of control
C6 glioma	Serum-free	N-CAM	5 μg/ml	62  ±  5
			2 μg/ml	87  ±  6
			1 μg/ml	102  ±  4
	bFGF	N-CAM	5 μg/ml	52  ±  7
			2 μg/ml	80  ±  6
			1 μg/ml	97  ±  9
NG-108 neuroblastoma	1% FBS	N-CAM	5 μg/ml	68  ±  4
			2 μg/ml	84  ±  3
			1 μg/ml	94  ±  4
	1% FBS	Ig III	10 μg/ml	70  ±  8
			3 μg/ml	79  ±  4
			1 μg/ml	93  ±  7
N2A neuroblastoma	Serum-free	N-CAM	5 μg/ml	80  ±  2
			2 μg/ml	92  ±  5
			1 μg/ml	100  ±  2
	Serum-free	Ig III	10 μg/ml	89  ±  4
			3 μg/ml	91  ±  2
			1 μg/ml	95  ±  3
Fibroblasts	Serum-free	N-CAM	5 μg/ml	20  ±  12
			2 μg/ml	74  ±  11
			1 μg/ml	93  ±  7
	Serum-free	Ig III	10 μg/ml	60  ±  5
			3 μg/ml	65  ±  9
			1 μg/ml	79  ±  10

Proliferation assays, as described in Experimental Procedures, were performed on C6 glioma, NG-108 neuroblastoma, N2A neuroblastoma, and primary fibroblasts. Concentrations of N-CAM or Ig III were added to the cells that were in serum-free media or in the presence of 1% fetal bovine serum (FBS) or bFGF (20 ng/ml). The amount of [³H]thymidine incorporation by cells in each condition was compared to cells treated with PBS alone. Data are presented as mean ± SD (n = 4 for each condition).