YF476 is a potent and highly selective cholecystokin 2 (CCK(2)) receptor antagonist of the
benzodiazepine class. It inhibits gastric neuroendocrine enterochromaffin-like (ECL) cell secretion, proliferation and spontaneous formation of gastric
neuroendocrine tumors (
carcinoids) in cotton rats. The Mastomys rodent species exhibits a
genetic predisposition to gastric ECL
neuroendocrine tumor formation which can be accelerated by acid suppression and induction of hypergastrinemia. In this respect, it mimics the human condition of
atrophic gastritis, hypergastrinemia and gastric
carcinoid development. We investigated whether
YF476 could inhibit acid suppression-induced ECL cell
hyperplasia and neoplasia in this model. In addition, we examined whether
YF476 could reverse established ECL cell
hyperplasia and neoplasia. Targeting the CCK(2) receptor during
Loxtidine-induced hypergastrinemia resulted in a reduction in ECL cell secretion (plasma and mucosal
histamine, and
histidine decarboxylase (HDC) transcripts, p<0.05) and proliferation (numbers of HDC-positive cells, connective tissue growth factor (CTGF) and
cyclin D1 transcription). This was associated with a decrease in ECL cell
hyperplasia and a 60% reduction in gastric ECL cell microcarcinoid (
tumors <0.3mm in size) formation.
YF476 inhibited ECL cell neoplasia (gastric
carcinoid) in animals with
hyperplasia, inhibited the formation of ECL cell
tumors when
co-administered with
Loxtidine and reversed the growth and developement of gastric ECL cell
carcinoids in long-term acid suppressed Mastomys. Variable importance analysis using a logistic multinomial regression model indicated the effects of
YF476 were specific to the ECL cell and alterations in ECL cell function reflected inhibition of transcripts for HDC,
Chromogranin A (CgA), CCK(2) and the autocrine growth factor, CTGF. We conclude that specifically targeting the CCK(2) receptor inhibits
gastrin-mediated ECL cell secretion and ECL cell proliferation and
tumor development in vivo.