Development of a meningioma in a patient with acromegaly during octreotide treatment: are there any causal relationships?
Somatostatin receptors are highly expressed in almost all meningiomas but in this setting their functional role is not clear. A 59-yr-old woman had been treated with octreotide after an unsuccessful operation for a GH-secreting pituitary adenoma. After 8 yr of treatment, a nuclear magnetic resonance (NMR) scan disclosed a 3 cm meningioma of the tentorium. Mean GH was 2.2 ng/ml and IGF-I 325 ng/ml. Meningioma was resected and tissue was digested to obtain tumor cell suspension. Aim of the study was to measure epidermal growth factor (EGF)-induced proliferation of cultured meningioma cells in the presence of either somatostatin or octreotide. Cells were grown to semiconfluency in Dolbecco's modified eagle medium (D-MEM) supplemented with 10% fetal calf serum (FCS). After 48 h in D-MEM without serum, the medium was replaced by fresh medium plus recombinant EGF (10 ng/ml) and somatostatin or octreotide were added in the final concentrations of 1, 10 and 100 nM. 20 h later 1 microcgCi of 3H-thymidine was added to each well. After 4 h, incorporated radioactivity was measured. While octreotide did not influence significantly cell growth at the three dose tested, somatostatin increased thymidine incorporation dose-dependently (peak 100 nM: 150% +/- 27% vs medium plus EGF, p<0.05). Octreotide effectively suppressed GH secretion in our acromegalic patient but is unlikely that its long-term use could have stimulated the growth of meningioma since it did not significantly influence the in vitro proliferation of the meningioma cells. These results suggest that somatostatin-mediated proliferative effect on meningioma cells is not mediated by the subtype 2 of the somatostatin receptor.
De Menis
E
E
Department of Internal Medicine, Hospital of Treviso, Brescia, Italy.
Tulipano
G
G
Villa
S
S
Billeci
D
D
Bonfanti
C
C
Pollara
P
P
Pauletto
P
P
Giustina
A
A
D000172:Acromegaly / Q000150:complications* / Q000188:drug therapy; D002455:Cell Division / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008577:Meningeal Neoplasms / Q000209:etiology* / Q000473:pathology; D008579:Meningioma / Q000209:etiology* / Q000473:pathology; D008875:Middle Aged; D015282:Octreotide / Q000009:adverse effects* / Q000627:therapeutic use; D017481:Receptors, Somatostatin / Q000187:drug effects*; D013004:Somatostatin / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use; D014407:Tumor Cells, Cultured
D017481:Receptors, Somatostatin; D013004:Somatostatin; D004815:Epidermal Growth Factor; C093733:somatostatin receptor 2; D015282:Octreotide