BETA-ENDORPHIN STIMULATES PROLIFERATION OF SMALL-CELL LUNG-CARCINOMA CELLS IN-VITRO VIA NONOPIOID BINDING-SITES

The small cell lung carcinoma cell line U-1690 bound beta-endorphin vi a nonopioid binding sites also recognized by the C-terminal part of th is opioid peptide Lys-Lys-Gly-Glu, but not by opiate alkaloids such as naloxone and morphine or other opioid peptides. The beta-endorphin bi nding did not affect the production of cAMP, but was enhanced by dexam ethasone pretreatment. The beta-endorphin-stimulated proliferation of U-1690 cells was inhibited by Lys-Lys-Gly-Glu and increased by dexamet hasone pretreatment. The cells also produce beta-endorphin, suggesting an autocrine mechanism. (C) 1995 Academic Press, Inc.