Adrenocortical carcinoma (AC) is a rare neoplasm with poor prognosis. Medical treatment of AC is actually based on the use of opDDD (mitotane) with or without traditional chemotherapeutic agents. Only very few information are available about the effectiveness of somatostatin analogs in AC. In human adrenal gland the expression of all five somatostatin receptor (SSTR) subtypes was previously demonstrated. A differential expression was shown in adrenal adenomas and carcinomas.
SOM230 is a new somatostatin analog able to interact with SSTR type 5. The effect of SOM230 on cell proliferation and hormone secretion was demonstrated in corticotroph pituitary adenomas primary cultures, but no data are available on adrenal gland.
The aim of the present study was to evaluate the effect of SOM230 on H295R, a human cell line derived from adrenal carcinoma. Cell proliferation was assessed by MTT-assay, whereas cortisol secretion was determined, with and without forskolin stimulation, using a competitive chemiluminescence immunoassay. Moreover, SSTR expression profile study was performed by RT-PCR.
SSTR 3, 4 and 5 were expressed in H295R cells, whereas no expression of SSTR1 and 2 was shown instead. The effect of SOM230 on H295R was determined in a 5 days treatment. A slight decrease of cell proliferation (11.4%) was observed after 72 h of treatment with a high dose of SOM230 (10−5M). At the same high dose (10−5M) SOM230 significantly (P<0.05) inhibits cortisol secretion already after 24 h. A lower concentration of the drug (10−8M) is effective only after 72 h of treatment.
These preliminary data show that SOM230 seems to have an effect on adrenal cell proliferation only at high dose, while a significant dose dependent effect on suppression on cortisol release was observed at 72 h also at low doses. Further studies are required to determine if SOM230 might be used for treatment of patients with AC.