Induction of the somatostatin receptor on colon carcinoma cells as a target for radiolabeled or cytotoxic somatostatin analogs

Abstract

In 1973 Brazeau et al. isolated and identified a 14-amino acid peptide, named somatotropin-release inhibiting factor (SRIF), later changed to somatostatin (SS)(1). Subsequently, research showed that somatostatin had two forms of bioactive peptides, somatostatin 14 and somatostatin 28, and that SS was widely distributed throughout the body with a wide variety of effects on endocrine, gastrointestinal and central nervous systems. The diversity of effects mediated by SS led to the suggestion that the hormone could have a therapeutical purpose in a great number of indications. However, due to the short half-life of SS (approximately 2 minutes) there were some restrictions in the use of natural SS as a drug. Therefore, researchers began to synthesize more stable peptide analogs with a longer duration of action, such as octreotide (SMS 201-995), lanreotide (BIM 23014) and vapreotide(2). These analogs not only proved to be more stable, but had also different affinity for the five different somatostatin receptors (SSRs), making their mode of action also more selective. These new finding led to a broad use of SS and their analogs in a clinical setting.