Alternatively Spliced Tissue Factor Is Expressed in Pancreatic Ductal Adenocarcinoma Lesions and Promotes Tumor Spread in an Orthotopic Setting
Kevin Turner, Ramprasad Srinivasan, Xiaoyang Qi, Bruce J Aronow, Holger Kalthoff, Fred Lucas, Vladimir Y Bogdanov. University of Cincinnati, Cincinnati, OH; Cincinnati Children's Hospital and Medical Center, Cincinnati, OH; University Hospital Schleswig-Holstein, Kiel, Germany
Background: Alternatively spliced tissue factor (asTF) is a minimally coagulant TF form that promotes neovascularization and monocyte recruitment via integrin ligation. While it has been shown that asTF is found in pancreatic ductal adenocarcinoma (PDAC) cell lines and that high asTF expression potentiates PDAC growth in a subcutaneous model, asTF presence in human PDAC tissue and its ability to promote metastatic spread have not previously been assessed.
Design: Tumor microarrays (PDAC, breast, urothelial, ovarian, and prostatic carcinomas) were evaluated for asTF expression and monocyte infiltration. Primary PDAC tumors and regional lymph node metastases were then analyzed. PDAC cell lines expressing various levels of asTF were implanted in the pancreases of nude mice and subsequent in-vivo imaging studies were performed. Grade I cell line Capan-1 was treated with recombinant asTF, and the resultant changes in gene expression were assessed using microarrays.
Results: While asTF protein was detected in lesional and stromal tissues in all five carcinoma types, PDAC tissue contained significantly higher levels of CD68+ monocytes (p<0.05). Analysis of 23 human cases of PDAC revealed detectable asTF in >90% of lesions with a range of staining intensities (low - 15%, medium - 70%, high - 15%). Lesional and stromal tissues showed varying intensities of cytoplasmic, perinuclear, and extracellular staining. Intense staining in cancer glands, perineurally invasive cancer glands, and pancreatic intraductal neoplasia lesions was identified. In nude mice, asTF-overexpressing cell line Pt45P1/asTF+ exhibited the most aggressive growth with metastases to distal lymph nodes, which stained intensely for asTF. Grade I PDAC line Capan-1 stimulated with asTF exhibited upregulation of genes involved in EGFR binding, epithelial branch elongation/development, and epithelial-mesenchymal signaling; EFEMP1, a gene recently shown to promote PDAC growth, was most upregulated in response to asTF.
Conclusions: We report for the first time that asTF 1) is expressed in PDAC lesions and lymph node metastases, 2) appears to fuel metastatic spread in an orthotopic model, and 3) elicits a tumor-promoting shift in gene expression in PDAC cells. asTF may thus be a promising new therapeutic target to treat PDAC.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 272, Monday Morning