Somatostatin (SRIF) analogues display anti-tumor properties believed t
o be mediated by specific cell surface somatostatin receptors (SSTR).
SSTR subtypes have unique pharmacological properties, including specif
ic GTP-binding protein coupling, ion channel regulation, and cAMP inhi
bition; therefore, identification of isotypes expressed in tumor cells
facilitates current efforts to design potent antitumor SRIF analogues
. Human and rodent solid, transplantable tumors and tumor cell lines w
ere examined for gene expression of SSTR1, SSTR2 and SSTR3 by reverse
transcription of tumor mRNA and subsequent amplification of cDNA by th
e polymerase chain reaction, using SSTR subtype-specific oligonucleoti
de primers. SSTR2 mRNA transcripts were observed in all of the tumor c
ell lines examined. SSTR1 gene expression was seen in several human an
d rat tumor types, and SSTR3 gene expression observed in two rodent tu
mor types. SSTR mRNA-positive tumors are expected to possess membrane-
bound receptors which could potentially interact with anti-tumor SRIF
analogues.