Growth of human pancreatic cancer is inhibited by down-regulation of gastrin gene expression.
OBJECTIVE
This study evaluated the effects of gastrin messenger RNA (mRNA) down-regulation on growth of human pancreatic cancer.


METHODS
Gastrin expression was examined in human pancreatic cancer cell lines by reverse transcriptase-polymerase chain reaction, and peptide expression was assessed by immunocytochemistry. Gastrin was down-regulated using either stable transfection of an antisense gastrin cDNA or 1 of 3 shRNA (short hairpin RNA) constructs. Tumor formation was evaluated after either subcutaneous or orthotopic injections into nude mice. The effect of nanoliposomes loaded with gastrin siRNA (small interfering RNA) was tested in mice bearing pancreatic tumors.


RESULTS
Stable transfection of gastrin antisense or shRNAs into BxPC-3 cells resulted in clones with more than 90% reduction in gastrin mRNA. Tumor growth rate and incidence of metastases in both wild-type and transfected pancreatic cancer cells were directly proportional to the degrees of gastrin mRNA expression. Immunofluorescence analysis confirmed that gastrin peptide levels were decreased in antisense and shRNA tumors. Gastrin knockdown clones had lower Ki-67 and increased cleaved caspase-3 staining, consistent with known effects of gastrin on proliferation and apoptosis. Tumors in mice treated with gastrin siRNA were smaller than controls.


CONCLUSIONS
These results suggest that RNAi targeting of gastrin could serve as an effective treatment for pancreatic cancer.
Matters
Gail L
GL
Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, PA 17011, USA.
Harms
John F
JF
McGovern
Christopher O
CO
Jayakumar
Calpurnia
C
Crepin
Keisha
K
Smith
Zachary P
ZP
Nelson
Melissa C
MC
Stock
Heather
H
Fenn
Craig W
CW
Kaiser
James
J
Kester
Mark
M
Smith
Jill P
JP
D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002851:Chromatography, High Pressure Liquid; D005455:Fluorescent Antibody Technique; D005755:Gastrins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis; D008081:Liposomes; D013058:Mass Spectrometry; D051379:Mice; D008819:Mice, Nude; D036103:Nanotechnology; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D047368:Tumor Burden; D023041:Xenograft Model Antitumor Assays
D005755:Gastrins; D019394:Ki-67 Antigen; D008081:Liposomes; D012333:RNA, Messenger; D034741:RNA, Small Interfering