ETS-Transcription Factor ETV1 Regulates Stromal Expansion and Metastasis in Pancreatic Cancer.
The ETS-transcription factor ETV1 is involved in epithelial-mesenchymal transition during pancreatic development and is induced in mouse pancreatic intraepithelial neoplasia (PanIN) and pancreatic ductal adenocarcinoma (PDAC). We investigated the function of ETV1 in stromal expansion of PDAC and metastasis, as well as its effects on a novel downstream target Sparc, which encodes a matricellular protein found in PDAC stroma that has been associated with invasiveness, metastasis and poor patient outcomes.



Pancreatic ductal cells were isolated from Pdx1Cre;Kras(G12D/+) mice (PanIN), Pdx1Cre;Kras(G12D/+);p53(fl/+) and Pdx1Cre;Kras(G12D/+);p53(fl/+);Rosa26(YFP) mice (PDAC), and Pdx1Cre;Kras(G12D/+);p53(fl/+);Sparc(-/-) mice. Cells were grown in 3-dimensional organoid culture to analyze morphology, proliferation, and invasion. Human PanIN and PDAC tissues were evaluated for ETV1 expression. Orthotopic pancreatic transplants of ETV1-overexpressing PDAC and respective control cells were performed.



ETV1 expression was significantly increased in human PanINs and, even more so, in primary and metastatic PDAC. Analyses of mouse orthotopic xenografts revealed that ETV1 induced significantly larger primary tumors than controls, with significantly increased stromal expansion, ascites and metastases. In 3-dimensional organoids, ETV1 disrupted cyst architecture, induced EMT, and increased invasive capacity. Furthermore, we identified Sparc as a novel functional gene target of Etv1 by luciferase assays, and SPARC and ETV1 proteins co-localized in vivo. Disruption of Sparc abrogates the phenotype of stromal expansion and metastasis found with ETV1 overexpression in vivo. We identified hyaluronan synthase 2 (Has2) as another novel downstream factor of Etv1; that may mediate ETV1's significant expansion of hyaluronic acid in PDAC stroma. Conversely, disruption of Etv1 in PDAC mice (Pdx1Cre;Kras(G12D/+);p53(fl/+);Rosa26(YFP);Cre;Etv1(fl/fl)) reduced levels of SPARC and hyaluronic acid in the stroma.



ETV1 is critical in the desmoplastic stromal expansion and metastatic progression of pancreatic cancer in mice, mediated functionally in part through Sparc and Has2.
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine II, Medical Center, University of Freiburg; Freiburg, Germany.
Steffen
S
Heeg
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Koushik K
KK
Das
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; II. Medizinische Klinik, Technical University of Munich, Munich, Germany.
Maximilian
M
Reichert
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Basil
B
Bakir
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Shigetsugu
S
Takano
Department of Medicine II, Medical Center, University of Freiburg; Freiburg, Germany.
Julia
J
Caspers
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Nicole M
NM
Aiello
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Katherine
K
Wu
Division of Gastroenterology and Gastrointestinal Oncology, University Medical Centre Goettingen, Goettingen, Germany.
Albrecht
A
Neesse
University of Texas, MD Anderson Cancer Center, Houston, Texas.
Anirban
A
Maitra
David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, New York.
Christine A
CA
Iacobuzio-Donahue
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Philip
P
Hicks
Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address: anil2@mail.med.upenn.edu.
Anil K
AK
Rustgi
D000818:Animals; D021441:Carcinoma, Pancreatic Ductal / Q000235:genetics* / Q000473:pathology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D051379:Mice; D009362:Neoplasm Metastasis / Q000235:genetics; D010183:Pancreatic Ducts / Q000166:cytology*; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D017154:Stromal Cells / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
D004268:DNA-Binding Proteins; C490641:Etv1 protein, mouse; D014157:Transcription Factors
Cancer; EMT; Gene Regulation; Pancreas