Growth <italic>In Vitro</italic> and Ultrastructure of Cells From a Medullary Carcinoma of the Human Thyroid Gland: Transformation by Simian Virus 40 and Evidence of Thyrocalcitonin and Prostaglandins

Abstract

Continuous monolayer tissue cultures were established with expiants from a metastatic nodule of medullary carcinoma primary in the thyroid gland. Some cultures were infected with simian virus 40 and the cells acquired morphologic and growth characteristics associated with viral transformation. Thyrocalcitonin activity was detected by radioimmunoassay of culture fluids as late as 7 months after initiation of the monolayers. Substances with the chemical and biological properties of prostaglandins PGE2 and PGF2α were extracted from culture fluids after 4 months. The original carcinoma cells contained abundant cytoplasmic secretory granules, which were demonstrated by electron microscopy. These granules disappeared during subculture of the monolayers, and electron-dense secretory substance accumulated within dilated cisternae of the ribosome-bound endoplasmic reticulum. Ultrastructural differences in surface organization of the virus transformed and uninfected culture cells were noted. Amyloid was present in the original fumor stroma and tissue culture expiants, but could not be identified in serial subcultures derived from the monolayer outgrowths.