Presence of nerve growth factor-like immunoreactivity in carcinoid tumour cells and induction of a neuronal phenotype in long-term culture.
Mid-gut carcinoid tumour cells expressed a neuronal phenotype, observed and characterized immunocytochemically in long-term culture. Initially the culture contained a main population of spherical tumour cells with granules immunopositive for serotonin (5-HT) and tachykinins (TK). Production and secretion of these substances into media was verified biochemically. Cytoplasmic granules with 5-HT-like immunoreactivity (5-HT-LI) were markedly reduced during culture, while granules with TK-LI were unchanged in number, corresponding to the biochemical findings. After a few days in culture, tumour cells were flattened and fine neurite-like processes extended. After 2-3 weeks many endocrine tumour cells had converted to neuron-like cells with slender cell processes containing granules with TK-LI. Varicose enlargements and apparent growth cones were observed. When neurites were extended, 50-80% of the neuron-like cells were positive with antisera against the neurofilament triplet. Cells of both endocrine and neuronal phenotypes were positive with antisera against tetanustoxin, Thy 1-antigen, neuron-specific enolase, synapsin and a synaptic vesicle protein (p 38) supporting the concept of these tumour cells as para-neurons. Intermediate filaments, studied with monoclonal anti-vimentin, were found in all cells. Filaments were also observed ultrastructurally. Initially, nerve growth factor (NGF)-LI was found in granules of all spherical tumour cells. When neuritic processes were extended, the cells appeared to lose these granules. After 40 days in culture, NGF-LI was absent or very sparse. The studies indicate autocrine secretion of a growth factor, reacting with the NGF antiserum, by cultured mid-gut carcinoid tumour cells inducing a neuronal phenotype with enhanced NF and TK synthesis and suppressed 5-HT synthesis. In bioassay systems the culture media caused a delayed neurite reaction on PC12 cells, but no reaction on chick ciliary ganglion cells, indicating that the factor is not authentic NGF.
Ahlman
H
H
Department of Surgery, University of Göteborg, Sweden.
Wigander
A
A
Mölne
J
J
Nilsson
O
O
Karlsson
J E
JE
Theodorsson
E
E
Dahlström
A
A
D002276:Carcinoid Tumor / Q000473:pathology* / Q000648:ultrastructure; D046508:Culture Techniques / Q000379:methods; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008207:Lymphatic Metastasis; D008854:Microscopy, Electron; D009362:Neoplasm Metastasis; D009414:Nerve Growth Factors / Q000032:analysis*; D009474:Neurons / Q000166:cytology* / Q000648:ultrastructure; D010641:Phenotype; D012701:Serotonin / Q000032:analysis; D014407:Tumor Cells, Cultured
D009414:Nerve Growth Factors; D012701:Serotonin