GASTRIN STIMULATES GROWTH OF HUMAN COLON-CANCER CELLS VIA A RECEPTOR OTHER THAN CCK-A OR CCK-B

Two receptors for cholecystokinin (CCK) have been isolated which also bind gastrin: CCK-A type and CCK-B type, both are coupled to phospholi pase C (PLC) activation. However, identification of the ''true'' gastr in receptor remains controversial. We determined which CCK receptor me diated the trophic effect of gastrin on human colon cancer cells (LoVo ). LoVo cells lack mRNA for either CCK receptor by Northern hybridizat ion. Gastrin stimulated cyclic AMP production, not PLC activity, in Lo Vo cells. The trophic effect was not blocked by receptor antagonists f or CCK-A (L364,718) or CCK-B (L365,260). The gastrin receptor pharmaco logy on LoVo cells and the lack of appropriate transcripts suggest tha t gastrin stimulated growth of these cells by a receptor other than CC K-A or CCK-B type and there likely exists another receptor for gastrin . (C) 1994 Academic Press, Inc.