The effects of 5-bromodeoxyuridine on the growth and morphology of transformed rat liver cells

Effects of 5-bromo-2'-deoxyuridine on arachidonic acid metabolism of neuroblastoma and leukemia cells in culture: a possible role of endogenous prostaglandins in tumor cell proliferation and differentiation

Effects of 5-bromo-2'-deoxyuridine (BrdU) were studied on two neuroblastoma and two leukemia cell lines, in terms of the relationship between prostaglandin (PG) synthesis and cell growth/differentiation. After treatment with BrdU (5 micrograms/ml), cell growth of the 4 cell lines was inhibited and one neuroblastoma cell line (GOTO) showed flattened morphology with positive S-100 protein, one of the differentiation markers for Schwann or glial cells. In the 4 cell lines, BrdU treatment reduced [1-(14)C]-arachidonic acid incorporation into phosphatidylinositol and phosphatidylethanolamine and was associated with an increase into phosphatidylcholine and triglyceride. BrdU treatment also increased fractions of 6-keto-PGF1 alpha and PGF2 alpha, with a decreased TXB2 fraction. The decreased ratio of TXB2/6-keto-PGF1 alpha or increased 6-keto-PGF1 alpha fraction correlated significantly with cell growth inhibition, suggesting that the changes in the balance of endogenous PGs might be associated with BrdU-induced cell growth inhibition with or without differentiation of neuro-blastoma and leukemia cells in culture.

Bromodeoxyuridine treatment of rat liver cells in culture induces an increased metabolic conversion of exogenous ornithine

In the presence of bromodeoxyuridine, rat liver cells show an increased incorporation of radiolabeled ornithine into cellular proteins. This increase was not due to activation of urea cycle enzymes but rather to an increase in metabolism of ornithine. Furthermore, treatment with bromodeoxyuridine changes profoundly and selectively the size of the free amino acid pool in these cells.

Antimitotic drugs that enhance neuronal survival in olfactory bulb cell cultures

Cell cultures of olfactory bulb from 2-3-day-old rats were used to evaluate 6 antimitotic drugs for their effects on neuronal survival. In cultures grown in medium without drugs for 7 days, neurons died as a layer of non-neuronal cells proliferated. A series of experiments were performed to determine dilutions and exposure times that allow maximum neuronal survival for each of the antimitotic drugs. Use of bromodeoxyuridine (BUdR) at 10(-5) M with a 5 day exposure gave cultures with large aggregates of neurons and an extensive network of interconnecting neurites. Cytosine arabinoside (Ara-C) at 8 X 10(-6) M for 5 days of exposure was also effective but the aggregates contained cellular debris. Fluorodeoxyuridine (FUdR) at 10(-4) for 5 days was less effective in flowing neurons to survive. Methotrexate (MTX), high thymidine and hydroxyurea were all not effective in allowing neuronal survival. In all cases there was an inverse relationship between the survival of neurons and proliferation of non-neuronal cells. Additional experiments were performed to determine how proliferating non-neuronal cells can lead to the death of neurons. In a series of transfer experiments, cultures were exposed to conditioned medium. Cultured olfactory bulb neurons grown on small cover slips were exposed to BUdR under optimal conditions and after 7 days were transferred to cultures treated or not treated with BUdR. In cultures not treated with BUdR, most of the transferred BUdR treated neurons died, while in cultures treated with BUdR the BUdR treated neurons survived. These results suggest that antimitotics enhance olfactory bulb neuronal survival by reducing the number of non-neuronal cells. In addition, it appears that proliferating non-neuronal cells are responsible for neuronal cell death by a medium factor and not by contact with the dividing non-neuronal cells.

Glycerol-3-phosphate dehydrogenase is induced by glucocorticoids in hepatocytes and hepatoma cells in vitro

Previous studies have shown that cytosolic glycerol-3-phosphate dehydrogenase (GPDH; EC 1.1.1.8) can be induced by glucocorticoids in mammalian brain, mammary gland, and thymus, but it was thought that no induction occurred in liver. We report here that GPDH is induced by glucocorticoids in several lines of hepatoma cells and in rat hepatocytes cultured in vitro. When rat hepatoma cells of clone FU5AH were exposed to 3 microM hydrocortisone (HC) for 3 days, GPDH specific activity increased greater than sixfold over control. The rate and extent of induction were similar in exponentially growing and stationary-phase cultures of cells. Four other hepatoma cell lines were inducible to a lesser extent, and three lines were not inducible. GPDH was also induced by glucocorticoids in cultures of hepatocytes isolated from livers of 6-day-old rats. The enzyme was induced three-to fourfold by the synthetic glucocorticoid, dexamethasone, in the presence of 1 nM insulin, but the induction was not observed in the absence of insulin.