Neuropeptides, antagonists and cell proliferation: bombesin as an example.

A variety of studies has recently demonstrated that a group of peptides with relatively low molecular weights may play an important role in the rate of proliferation of tumor cells in vitro and in vivo. Among these peptides are bombesin and gastrin-releasing peptide (GRP) which both can function as autocrine growth factors in several neoplastic cells. These two neuropeptides also act as gut hormones and neuromediators. In this family of peptides, a shared C-terminal sequence is necessary for biological activity. The knowledge of this sequence provided a structural basis for the design of synthetic antagonists. Such agents are capable of interfering with the processing or the release of the autocrine growth factor or with its receptor, and might have a potential therapeutic utility. This short paper, focused on one class of neuropeptides, is not intended as an extensive review of this rapidly expanding field, but rather a survey of several topics presently under investigation.