No abstract

A membrane receptor and a cytosolic receptor for somatostatin were found in a human undifferentiated pancreatic cancer cell line (MIA PaCa-2). Binding of somatostatin to this membrane receptor activates dephosphorylation of a phosphotyrosyl-membrane protein whose phosphorylation was promoted by epiderma1 growth factor (EGF). Vanadate, a purported inhibitor of dephosphorylation, interferes with the action of somatostatin. These findings suggest a possible biochemical mechanism by which somatostatin may inhibit the growth of human pancreatic cancers.

The effects of epidermal growth factor (EGF) and somatostatin-14 (SS) on growth of Mia PaCa-2 cells in cell culture were examined. EGF had no effect on cell growth in sera containing media but significantly increased growth in sera-free media. The effect of EGF was complete within 18 h. SS added with EGF entirely eliminated the growth stimulation of EGF. SS added to cells in culture with sera inhibited their growth as well.