Cholecystokinin receptors in human pancreatic cancer cell lines

Recent studies have suggested that cholecystokinin (CCK) receptors may play a role in the development and growth of pancreatic cancers. We detected the expression of mRNA encoding CCK-A and CCK-B receptors in eight human pancreatic tumour cell lines using reverse transcription-polymerase chain reaction (RT-PCR), but not by RNase protection assays. The K-ras gene, which can be activated by G-coupled protein receptors such as CCK receptors, was mutated in codon 12 in five of the cell lines. In addition, Mia PaCa-2 pancreatic cancer cells did not respond to CCK or gastrin in cell proliferation or focal adhesion kinase (FAK) phosphorylation assays. In contrast, mouse NIH3T3 fibroblasts transfected with human CCK-B receptor (NIH3T3CCK-BR) showed increased proliferation and phosphorylation to the peptides. Also, radioligand binding studies indicated that Mia PaCa-2 cells had approximately 12.5-fold less CCK-B receptors than NIH3T3CCK-BR. Our results suggest that in Mia PaCa-2 cells, CCK receptors may not play a crucial role in supporting cell growth.