A comparison of lipid metabolism in two human retinoblastoma cell lines.

A number of differences have been observed in the lipid metabolism of cultured Y79 and WERI Rb-1 retinoblastoma cells. The Y79 cells have a higher phospholipid content and a higher percentage of ethanolamine phosphoglycerides, whereas the WERI Rb-1 cells have more triglycerides. This is consistent with the finding that most of the polyunsaturated fatty acid taken up by the Y79 cells is incorporated into phospholipids, while a sizable amount of the uptake in WERI Rb-1 cells is incorporated into triglyceride. Polyunsaturated fatty acids of the n-6 class are taken up at about the same rate by both cells, but the n-3 polyunsaturates are taken up more rapidly by the Y79 cells. In addition, the Y79 cells convert a larger percentage of linoleic acid (18:2, n-6) to arachidonic acid (20:4, n-6) and of linolenic acid (18:3, n-3) to docosahexaenoic acid (22:6, n-3), and they accumulate these products when the precursors are added to the culture medium. When grown in 10% fetal bovine serum without supplemental fatty acid, however, the WERI Rb-1 contain more arachidonic and docosahexaenoic acids. These differences in lipid content and metabolism suggest that although the Y79 and WERI Rb-1 cell lines are derived from the same type of retinal tumor, they either originated from functionally different retinal neurons or have diverged biochemically during propagation in culture.