NOVEL EXPRESSION AND REGULATION OF GASTRIN GENE IN HUMAN OVARIAN-CANCER CELL-LINE, SW626

Gastrin-secreting tumors have been identified in ectopic locations inc luding the ovary; the mechanisms regulating gastrin gene expression, i ts distribution, and signaling pathways in these ectopic tissues are n ot known. The purpose of our present study was to determine: (1) wheth er the gastrin gene and peptide could be detected in ovarian cancer ce ll lines, (2) if functional gastrin releasing peptide receptors (GRP-R ) are present, and (3) whether gastrin gene expression is altered by G RP. Five ovarian cancer cell lines (SW626, OVCA 420, OVCA 429, OVCA 43 2, and OVCA 433) were analyzed. We identified gastrin gene and peptide expression in the SW626 cell line but not in the OVCA lines. SW626 ce lls express a functional GRP-R that is correctly coupled to the Ca2+ s ignaling pathway. Treatment of SW626 cells with bombesin, the amphibia n equivalent of GRP, inhibited expression of the gastrin gene in a tim e- and dose-dependent fashion. The SW626 ovarian cancer cell line will provide a useful model to further define regulation and expression of both the gastrin gene and peptide in ectopic (nongastrointestinal) ti ssues.