Targeting of cholecystokinin B/gastrin receptor in colonic, pancreatic and hepatocellular carcinoma cell lines.
Gastrin is a growth factor for both gastrointestinal and non-gastrointestinal tumours. Endocytosis of gastrin has been demonstrated in tumour cell lines expressing cholecystokinin-B/gastrin receptor (CCK-BR); this has raised the possibility of receptor targeted therapy. The aim of this study was to examine endocytosis of gastrin and CCK-BR in tumour cell lines. A small gastrin analogue, RG-G7, and the anti-CCK-BR antibody, anti-GRE1, were fluorescently labelled and uptake by cancer cell lines including AR42J, HepG2, and C170HM2 as well as transfected NIH3T3 fibroblast cells was assessed using standard and confocal fluorescence microscopy. CCK-BR expression of cell lines was assayed by reverse transcription-polymerase chain reaction and Western blotting. Apoptosis was detected using a fluorescent TUNEL method. RG-G7 and anti-GRE1 antibody were specifically taken up by all cell lines expressing CCK-BR. In addition to cytoplasmic uptake with RG-G7 and anti-GRE1 the latter also showed specific uptake into the nucleus. A coincidence of anti-GRE1 and apoptosis was seen. Targeting CCK-BR by peptide or antibody may offer therapeutic opportunities for some cancers.
Savage
Kay
K
Department of Histopathology, Royal Free Hospital, Hampstead, London NW3 2QG, UK.
Waller
H Anne
HA
Stubbs
Mark
M
Khan
Korsa
K
Watson
Susan A
SA
Clarke
Philip A
PA
Grimes
Steve
S
Michaeli
Dov
D
Dhillon
Amar P
AP
Caplin
Martyn E
ME
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004705:Endocytosis; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018613:Microscopy, Confocal / Q000379:methods; D041681:NIH 3T3 Cells; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D043887:Receptor, Cholecystokinin B / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D043887:Receptor, Cholecystokinin B