Defective internalization of low density lipoprotein in epidermoid cervical cancer cells.

Abstract

Cells of an epidermoid cancer cell line [EC 168] of human uterine cervix, which possessed a high-affinity, specific receptor for low density lipoprotein (LDL), internalized and degraded [125I]iodo-LDL at very low rate. In these cells, LDL did not stimulate cholesteryl ester synthesis, nor did it suppress 3-hydroxy-3-methylglutaryl CoA reductase to the same extent as in the control cells. The binding of [125I]iodo-LDL by these cells was not decreased by preincubation of the cells in medium containing LDL. Using ferritin-labeled LDL (F-LDL) and EM, it was determined that at 4.degree. C the cells bound F-LDL in the same way as other cancer cell lines that did not have a defect in internalization. When these cells were warmed to 37.degree. C the F-LDL remained on the surface, whereas in cells from control cancer cell lines the F-LDL was internalized and was no longer observed on the cell surface. Cells of this epidermoid cancer cell line apparently have a defective ability to internalize LDL.