Establishment and characterization of three novel cell lines - P-STS, L-STS, H-STS - derived from a human metastatic midgut carcinoid.

Carcinoids are rare tumors derived from enterochromaffin (EC) cells of the embryonic neural crest. They have malignant potential and their incidence is steadily increasing. The only curative treatment option is surgery. We have focused on cultivation of human neuroendocrine tumors (NET) as relevant models for the study of potential therapy. Only a few cell lines from human carcinoids have been established so far, among them our earlier KRJ-I cell line from a human ileal carcinoid. The reason for the poor success in establishing carcinoid cell lines is due to the small amount of tissue available and the low mitotic activity in primary cultures. We have successfully established three continuously growing cell lines from tissue obtained from a metastatic human carcinoid of the terminal ileum (midgut carcinoid): P-STS was derived from the primary tumor, L-STS from a lymph node metastasis and H-STS from a hepatic metastasis. Immunocytochemistry proved the maintenance of characteristic neuroendocrine properties. Electron microscopy confirmed the presence of neuroendocrine granules. The three cell lines were tumorigenous in SCID-mice. Cytogenetic analyses revealed clonal tetraploidy, inversion and deletion in chromosome 18q, and non-clonal numerical and structural aberrations. Array CGH did not show notable imbalances. Mutation screening of P-STS excluded a MEN1-gene-associated genetic predisposition with high probability. The novel cell lines P-STS, L-STS and H-STS may be useful in vitro and in vivo models for further studies of biological characteristics and the development of new therapeutic agents.