agar and Adenoma

Human pituitary tumors were studied in vitro using the clonogenic stem cell assay. Mechanical dispersion was used to prepare single cell suspensions for plating. Colony formation occurred in 21 of 24 tumors plated. Bromocriptine (Brc; 10 nM) added to the medium resulted in a significant decrease in the number of colonies formed in 5 of 10 prolactinomas and in 1 tumor secreting both PRL and GH. However, PRL secretion was decreased in 8 of 9 tumors tested. Brc had no effect on either colony formation or hormone secretion in other tumors secreting GH (n = 2), ACTH (n = 2), or FSH (n = 1) or in nonsecreting tumors (n = 4). Tamoxifen (Tam; 10(-7) M) inhibited colony formation in 6 of 10 prolactinomas and in 1 tumor secreting GH and PRL. PRL secretion into the medium correlated with the changes in the number of colonies. Tam was not effective in any other tumor tested. In only 1 instance was there a synergistic action between Brc and Tam on inhibition of colony formation. Brc, but not Tam, caused a significant decrease in the size of the colonies formed from cells of PRL-secreting tumors. The least numbers of colonies per plate were found in 3 prolactinomas from patients treated preoperatively with Brc. We conclude that the soft agar clonogenic assay technique is a feasible method to study human pituitary tumors in vitro. Both Brc and Tam inhibited colony formation in this system in a significant proportion of tumors. The potential antiproliferative action of Tam in vivo needs to be studied in view of these results.

Topics: Adenoma; Agar; Bromocriptine; Cells, Cultured; Clone Cells; Female; Growth Hormone; Humans; Male; Pituitary Neoplasms; Prolactin; Tamoxifen

To examine the role of germinal mutation in transformation by phorbol esters, we studied the induction of anchorage-independent variants of mutant human diploid fibroblasts derived from normal-appearing skin of individuals with hereditary adenomatosis of the colon and rectum (ACR). Liquid cultures were chronically exposed to 12-0-tetradecanoyl phorbol-13-acetate (TPA), then plated in agar and injected subcutaneously into athymic mice. Cultured ACR cells showed an unusual biphasic dose response to TPA. Colony-forming cells in agar were obtained at a frequency of about 5 x 10(-5). They did not, however, seem to increase in frequency during subsequent passages in liquid cultures continuously exposed to TPA. The isolated anchorage-transformed clones showed an altered clonal morphology and a considerable increase in cloning efficiency in liquid cultures and agar. The results suggest that ACR cells may be used to screen for potential tumor promoters in our environment.

Topics: Adenoma; Agar; Animals; Cell Transformation, Neoplastic; Cells, Cultured; Colonic Neoplasms; Fibroblasts; Humans; Mice; Mice, Nude; Neoplasm Transplantation; Phorbols; Rectal Neoplasms; Skin; Tetradecanoylphorbol Acetate

Topics: Adenoma; Agar; Neoplasms; Parathyroid Glands; Parathyroid Neoplasms; Tissue Culture Techniques