Dickkopf‐1 is overexpressed in human pancreatic ductal adenocarcinoma cells and is involved in invasive growth

• Published in: International journal of cancer 2010-04, Vol.126 (7), p.1611-1620
• Main Authors: Takahashi, Nobuyasu, Fukushima, Tsuyoshi, Yorita, Kenji, Tanaka, Hiroyuki, Chijiiwa, Kazuo, Kataoka, Hiroaki
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Biological and medical sciences; Blotting, Western; Carcinoma, Pancreatic Ductal - genetics; Carcinoma, Pancreatic Ductal - metabolism; Carcinoma, Pancreatic Ductal - pathology; Cell Movement; Cell Proliferation; DKK‐1; ductal adenocarcinoma; Gastroenterology. Liver. Pancreas. Abdomen; Humans; Immunoblotting; Immunoenzyme Techniques; Intercellular Signaling Peptides and Proteins - genetics; Intercellular Signaling Peptides and Proteins - metabolism; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Male; Medical sciences; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Invasiveness; pancreatic cancer; Pancreatic Neoplasms - genetics; Pancreatic Neoplasms - metabolism; Pancreatic Neoplasms - pathology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Small Interfering - pharmacology; Tumor Cells, Cultured; Tumors; wnt signal
• ISSN: 0020-7136; 1097-0215
• DOI: 10.1002/ijc.24865

The protein products of the Dickkopf (DKK) genes are antagonists of Wnt glycoproteins, which participate in tumor development and progression by binding to frizzled receptors. In this study, the expression of DKK‐1 was analyzed in a panel of 43 human cultured carcinoma cell lines. DKK‐1 expression was consistently and significantly upregulated in pancreatic carcinoma cell lines. Low level of DKK‐3 expression was also seen. In contrast, the expression of DKK‐2 and ‐4 was not detectable in most pancreatic carcinoma cell lines. The overexpression of DKK‐1 was confirmed in surgically resected human pancreatic cancer tissues, in which the mRNA level was evaluated in paired samples from cancerous and noncancerous pancreatic tissues. In ductal adenocarcinomas (23 cases), DKK‐1 mRNA levels were significantly upregulated compared to corresponding noncancerous tissues in a statistically significant level. To test the biological role of DKK‐1 in pancreatic carcinoma cells, we performed a knockdown of DKK‐1 in SUIT‐2 human pancreatic adenocarcinoma cell line and S2‐CP8, its metastatic subline, using a retroviral short hairpin RNA expression vector. DKK‐1 knockdown resulted in reduced migratory activity of SUIT‐2 in vitro. The in vitro growth rate and Matrigel invasion were also suppressed by DKK‐1 knockdown in S2‐CP8 cells. Collectively, the evidence suggests that, despite of its presumed antagonistic role in Wnt signaling, DKK‐1 may have a role in the aggressiveness of pancreatic carcinoma cells and could, therefore, serve as a novel biomarker of pancreatic cancer.