tretinoin and phorbol-12-13-didecanoate

When established in culture, human neuroblastoma cell lines typically are comprised of heterogeneous cellular subpopulations, including neuroblastic (N-type), substrate-adherent (S-type), and intermediate (I-type) cells that can be distinguished by their characteristic morphologies and expression of differentiation-associated antigens. Here we examined the relative levels of the Bcl-2 oncoprotein in 15 clones derived from four different neuroblastoma cell lines. Among six clones isolated from the SK-N-SH line, levels of p26-Bcl-2 correlated with morphology and differentiation markers with the hierarchy of bcl-2 expression being: N-type cells > N/I-type > I-type > S-type. Furthermore, stimulation of one of the N-type clones, SH-SY5Y, with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate, induced differentiation toward a more neuronal-like phenotype and resulted in a 5- to 10-fold elevation in the relative levels of Bcl-2 protein. High relative amounts of p26-Bcl-2 protein were also found in an N-type clone derived from the SMS-KCN line. In two N-type clones derived from the LA-N-1 line, however, levels of Bcl-2 protein were only moderately elevated, and in one N-type clone from the SK-N-BE(2) line the levels of Bcl-2 protein were low. Thus, high relative levels of Bcl-2 oncoprotein are not a universal feature of N-type cells (three of six clones tested). In contrast, all 5 of the S-type clones evaluated contained relatively low levels of Bcl-2 protein, suggesting that these cells (which may represent embryonic precursors of Schwann, glial, and melanocytic cells) do not typically express the bcl-2 gene at high levels. Consistent with this inverse correlation between Bcl-2 protein levels and S-type characteristics, stimulation of an I-type clone derived from the SK-N-BE(2) line with 5-bromodeoxyuridine was accompanied by an accumulation of S-type cells in these cultures, decreased Bcl-2 protein, diminutions in the neuronal markers neurofilament-M and neuron-specific enolase, and an increase in the relative levels of the S-type marker proteins vimentin and beta-2-microglobulin. Conversely, stimulation of this I-type clone with retinoic acid resulted in an accumulation of N-type cells (which are thought to represent embryonic precursors of sympathetic neurons), decreased vimentin and beta-2-microglobulin, increased neurofilament-M, and a marked elevation in p26-Bcl-2.(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Antineoplastic Agents; Carcinogens; Cell Differentiation; Cell Division; Cell Line; Cell Survival; Clone Cells; Drug Resistance; Gene Expression Regulation, Neoplastic; Humans; Kinetics; Neuroblastoma; Oncogenes; Phorbol Esters; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Tetradecanoylphorbol Acetate; Time Factors; Transfection; Tretinoin; Tumor Cells, Cultured

Prophase I oocytes, free of follicle cells, and metaphase II eggs of the amphibian Xenopus laevis were subjected to transient treatments with the protein kinase C activators, phorbol 12-myristate 13-acetate (PMA), phorbol 12,13-didecanoate, and 1-olyeoyl-2-acetyl-sn-glycerol. In both oocytes and eggs, these treatments triggered early events of amphibian development: cortical granule exocytosis, cortical contraction, and cleavage furrow formation. Surprisingly, activation of oocytes occurred in the absence of meiotic resumption, resulting in cells with an oocytelike nucleus and interior cytoplasm, but with a zygotelike cortex. PMA-induced activation of oocytes and eggs did not require external calcium, a prerequisite for normal activation of eggs. PMA-induced activation of eggs was inhibited by retinoic acid, a known inhibitor of protein kinase C. In addition, pretreatment of eggs with retinoic acid prevented activation by mechanical stimulation and inhibited activation by calcium ionophore A23187. The results suggest that protein kinase C activation is an integral component of the Xenopus fertilization pathway.

Topics: Animals; Calcimycin; Calcium; Diglycerides; Enzyme Activation; Exocytosis; Oocytes; Ovum; Phorbol Esters; Protein Kinase C; Tetradecanoylphorbol Acetate; Tretinoin; Xenopus laevis

There is a marked increase in the activity of sialic acid lyase (N-acetylneuraminate lyase; EC 4.1.3.3; also known as sialic acid aldolase) in HL-60 cells induced to differentiate into macrophages by the phorbol ester, tetradecanoylphorbol 12-myristate 13 acetate (TPA). Exposure of HL-60 cells to retinoic acid, butyric acid or dimethyl sulfoxide has little or no effect. The level of the enzyme remains unaltered in HL-60 cells grown in the presence of an inactive analog of TPA, nor does it change in variants of HL-60 cells resistant to TPA.

Topics: beta-D-Galactoside alpha 2-6-Sialyltransferase; Butyrates; Butyric Acid; Cell Differentiation; Cell Line; Dimethyl Sulfoxide; Humans; Leukemia, Lymphoid; Oxo-Acid-Lyases; Phorbol Esters; Sialyltransferases; Tetradecanoylphorbol Acetate; Tretinoin

Mast cell colonies grew in methylcellulose when mouse spleen cells were cultured for 14 days in the presence of medium conditioned by concanavalin A-stimulated spleen cells. Tumor-promoting phorbol esters, 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12,13-didecanoate, enhanced the concanavalin A-stimulated spleen cell-conditioned medium-induced colony growth of mast cell progenitors. The effect of TPA on this colony growth was blocked by the addition of two antipromoters of experimental skin carcinogenesis, i.e., retinoic acid and dexamethasone. These results show that TPA has the ability to enhance the clonal proliferation of mouse mast cells and that this effect of TPA is closely related to tumor-promoting activity.

Topics: Animals; Carcinogens; Cell Division; Cells, Cultured; Clone Cells; Dexamethasone; Female; Kinetics; Mast Cells; Mice; Mice, Inbred BALB C; Phorbol Esters; Phorbols; Tetradecanoylphorbol Acetate; Tretinoin