Gene expression of somatostatin receptor subtypes, SSTR1 and SSTR2, in human lung cancer cell lines

Somatostatin (SS) acts as a universal endocrine off-swich, and also inhibits the growth of neuroendocrine tumors through its specific receptors. Small cell lung cancer (SCLC) demonstrates some neuroendocrine characteristics and has been proposed as a candidate for treatment with SS and its analogues. In the present study, we investigated the expression of somatostatin receptor (SSTR) subtype (SSTR1 and SSTR2) mRNA in various human lung cancer cell lines by the sensitive reverse-transcription-PCR method and Southern blotting. The levels of expression of SSTR1 mRNA were higher in both SCLC and squamous cell carcinoma than in adenocarcinoma cell lines. Interestingly, SSTR1 gene expression was independent of that of SSTR2 in each SCLC cell line, although the expression of both genes showed a positive correlation in non-SCLC cells. Membranes from a cell line exhibiting highest expression of SSTR2 gene bound SS and its analogue, octreotide, with moderate affinity. These findings may provide useful information for the future clinical application of SS and its analogues for the treatment of lung cancer.