Multiple neuropeptides stimulate clonal growth of small cell lung cancer: effects of bradykinin, vasopressin, cholecystokinin, galanin, and neurotensin.

We tested whether Ca(2+)-mobilizing neuropeptides can function as growth factors for small cell lung carcinoma cells. The neuropeptides bradykinin, neurotensin, cholecystokinin, and vasopressin at nanomolar concentrations stimulated a rapid and transient increase in the intracellular concentration of Ca2+. Crucially, these peptides in the same concentration range also caused a marked increase in colony formation in semisolid medium in responsive small cell lung carcinoma cell lines. At optimal concentrations bradykinin, neurotensin, cholecystokinin, vasopressin, galanin, and gastrin-releasing peptide were equally effective in promoting clonal growth. These findings support the hypothesis that small cell lung carcinoma growth is sustained by an extensive network of autocrine and paracrine interactions involving multiple neuropeptides.