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Promoting role of cholecystokinin 2 receptor (CCK2R) in gastrointestinal stromal tumour pathogenesis
Author(s) -
Quattrone Anna,
Dewaele Barbara,
Wozniak Agnieszka,
Bauters Marijke,
Vanspauwen Vanessa,
Floris Giuseppe,
Schöffski Patrick,
Chibon Frederic,
Coindre JeanMichel,
Sciot Raf,
DebiecRychter Maria
Publication year - 2012
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/path.4071
Subject(s) - cholecystokinin b receptor , immunohistochemistry , pathology , pathogenesis , gastrin , stromal cell , gist , medicine , cancer research , biology , cholecystokinin , receptor , secretion
Abstract The cholecystokinin 2 receptor (CCK2R/CCKBR) is expressed in gastrointestinal stromal tumours (GISTs). We sought to investigate the role of CCK2R in GIST pathogenesis. Molecular characterization of CCK2R was performed on a heterogeneous cohort of 50 GISTs. In addition, CCK2R expression was evaluated by immunohistochemistry (IHC), using tissue microarray (TMA) containing 292 GISTs, two cases of hyperplasia of interstitial Cajal's cells (ICC) and six gastric microscopic GISTs. Mono‐allelic loss of the CCK2R /11p15 allele was identified in 13.7% of GISTs, having no impact on the level of CCK2R transcript expression. No CCK2R mutations were found. The CCK2Ri4sv , CCK2R splice variant with retention of intron 4 was detected in six of 20 tumours analysed. Wild‐type CCK2R transcripts were commonly expressed (57.1% of cases) and this expression was highly correlated with gastric primary site of GISTs ( p < 0.001). At the protein level, expression of CCK2R in incidental ICC hyperplasia and early stages of gastric GIST development was documented, and its gastric association was confirmed on GIST‐TMA by IHC. To explore the in vivo effect of CCK2R activation on tumour growth, gastrin versus placebo was administered intraperitoneally in nude mice carrying human GIST xenografts. The tumour volume was followed for 10 weeks. The effect of this stimulation on tumour cell proliferation/apoptosis was assessed by IHC and KIT/PKC‐θ signalling was evaluated by western blotting (WB). In vivo experiments showed a two‐fold increase in the volume of tumours which were exposed to gastrin in comparison with non‐exposed controls ( p = 0.03), with a significant increase in mitotic activity ( p = 0.04) and Ki‐67 proliferation index ( p = 0.008). By WB, gastrin stimulation resulted in hyper‐activation of KIT and PKC ‐θ kinases, and in evident PI3K‐AKT pathway over‐activation. Our results indicate a promoting role of CCK2R on GIST tumourigenesis, particularly in tumours of gastric origin. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.