Studies on in vitro release of cytoplasmic enzymes and nucleic acids from Ehrlich ascites tumor cells into surrounding medium.

The in vitro release of a wide variety of cytoplasmic enzymes, LDH, MDH, ICDH, 6PGDH, G6PDH, PFK and GOT, from mouse Ehrlich ascites tumor cells into the surrounding medium was studied. In every case, no appreciable enzyme release was observed under aerobic condition, whereas under anaerobic conditions there was aa marked release of enzymes. This type of enzyme release can be prevented by glucose. In an aerobic state, only the conditions leading to the impairment of aerobic ATP generation caused a substantial enzyme leakage. The dye exclusion test with trypan blue proved that the appearance of enzyme activities in anaerobic incubation media is not due to cell lysis. The percentage of enzyme activity appearing in the incubation medium was highest with 6PGDH and G6PDH, amounting to almost 30% of the initial cellular levels. No clear-cut inverse relationship was observed between the degree of the release of enzymes and their respective molecular weight. The chromatographic studies on nucleic acids released from the tumor cells revealed that there was a preferential release of higher molecular RNA to lower molecular RNA. Comparison of several cultured cell lines indicated that malignant cells re-lease enzymes to a much greater extent than do benign cells.