Analysis of Enzymatic Activities of Clones Derived From Variant Cell Lines Transformed to Malignant Cells in Tissue Culture

Abstract

Two cell lines, derived in vitro from one cell isolated from a culture of normal mouse tissue, were found in previous studies to differ in morphology, metabolism, and rate of growth to form malignant tumors in mice of the strain of origin (C3H). When cells of one line, designated low tumor-producing or “low,” were injected into mice, tumors developed slowly or not at all, whereas tumors developed rapidly from implants of the other cell line, designated high tumor-producing or “high.” Three clones established from single cells of the low line and one clone from the high line have been investigated to determine whether there is any correlation between activities of some enzymes metabolizing glucose oxidatively and the rate of growth into tumors when cells are implanted in mice. The activities of the enzymes hexokinase, glucose-6-phosphate dehydrogenase, and phosphogluconate dehydrogenase have been determined in the whole cells and in cell-free extracts of the cells. The mean specific activities of all 3 enzymes were very similar for 2 of the clones from the low line. The third of the clones from the low line that differed in certain other characteristics had the same phosphogluconate activity, a 50 percent higher hexokinase activity, and twice the glucose-6-phosphate dehydrogenase activity. The clone derived from the high line had nearly 3 times the hexokinase activity, 4 times the glucose-6-phosphate dehydrogenase activity, and 5 times the phosphogluconate dehydrogenase activity compared with 2 of the low-line clones. The differences between the derivative clones from low and high lines are even greater when the enzyme activities of the whole cells or the extracts are calculated per cell.