pituitrin and Neoplasms--Nerve-Tissue

A variety of cells found in the pituitary and pineal glands, sympathetic nervous system and adrenal glands, the gut, pancreas, thyroid (C-cells), chemoreceptors (type I-Cells), lungs (P-cells), skin (melanocytes) and the urogenital tract have a common origin from the neural crest. These cells are programmed for neuro-endocrine function and, as a group, can be regarded as one of the physiological control systems. They secrete a variety of amine and peptide hormones and have common cytochemical characteristics from which the term APUD cell is derived. Tumours of these cells are referred to as 'apudomas' and may synthesise not only their own hormones but also those which are normally produced by other APUD cells. The relevant physiological properties of some of the peptides which have been described relatively recently are discussed and the principal clinical syndromes produced by the APUDomas are described.

Topics: Adenoma, Islet Cell; APUD Cells; Apudoma; Cushing Syndrome; Endocrine System Diseases; Gastrointestinal Neoplasms; Hormones; Humans; Malignant Carcinoid Syndrome; Neoplasms, Nerve Tissue; Pancreatic Neoplasms; Paraneoplastic Endocrine Syndromes; Pheochromocytoma; Pituitary Neoplasms; Thyroid Neoplasms; Vasopressins; Zollinger-Ellison Syndrome

The presence of 3 different neuropeptide mRNAs with a strict cell-specific expression in vivo was investigated in 13 tumor cell lines from neuroendocrine and in 23 tumor cell lines from non-neuroendocrine origin. Northern blots showed no expression of mRNA for vasopressin (VP) in the 36 tested cell lines. Very low oxytocin (OT) mRNA hybridization signals were detected in the rat pituitary tumor cell line GH4C2 and the rat pancreas tumor cell line RIN5. Both the rat pituitary tumor cell line AtT-20 and the human myeloid leukemia cell line K562, contained proopiomelanocortin (POMC) mRNA. The low incidence of VP, OT and POMC gene expression in the tested tumor cell lines was not influenced by treatments inducing differentiation. In contrast, the cholecystokinin (CCK) gene which is widely present in nervous and endocrine systems was abundantly expressed in the human primitive neuroepithelioma cell line SK-N-MC and its clonal derivative SK-N-MC-IX-C. The results indicate that the expression of neuropeptide genes is very rare in tumor cell lines. The lack of expression in undifferentiated cells agrees with the appearance of expression after day 13 of the embryogenesis when maturation of neurons begins.

Topics: Animals; Blotting, Northern; Cell Differentiation; Cholecystokinin; Gene Expression Regulation, Neoplastic; Humans; Mice; Neoplasms; Neoplasms, Experimental; Neoplasms, Nerve Tissue; Neuropeptides; Oxytocin; Paraneoplastic Endocrine Syndromes; Pro-Opiomelanocortin; Rats; RNA, Messenger; RNA, Neoplasm; Swine; Tumor Cells, Cultured; Vasopressins