Poster Presentation 28th Lorne Cancer Conference 2016

Pancreatic cancer invasion and stromal remodelling is dependent on uPA and regulated by SerpinB2  (#158)

Nathanial L.E. Harris 1 2 3 , Claire Vennin 4 5 , James R.W. Conway 4 5 , Kara Perrow 1 2 3 , Robert F Shearer 4 5 , Mark Pinese 4 5 , Marina Pajic 4 5 , Morghan Lucas 4 , Jennifer Morton 6 , Paul Timpson 4 5 , Marie Ranson 1 2 3 , Darren N Saunders 4 5 7
  1. Center for Medical Bioscience , University of Wollongong, Wollongong, NSW, Australia
  2. Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
  3. Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
  4. Kinghorn Cancer Centre, Garvan Medical Research Institute, Sydney, NSW, Australia
  5. St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
  6. The Beatson Institute for Cancer Research, University of Glasgow, Glasgow, Scotland.
  7. School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia

Pancreatic ductal adenocarcinoma (PDAC) has a devastating prognosis, with an overall five-year survival rate of ~5%, severely restricted treatment options, and characterised by a high degree of molecular heterogeneity. Overexpression of the serine protease urokinase (uPA) is recognised as an important biomarker of metastatic disease and a druggable cancer target. Further, expression of the specific uPA inhibitor, SerpinB2, has been associated with metastasis and survival in several solid tumour types, including PDAC. In a large cohort of resected PDAC (Australian Pancreatic Cancer Genome Initiative, n = 141) increased levels of uPA mRNA expression was significantly associated with poorer survival following pancreatectomy (Cox model coefficient 0.387; likelihood ratio P = 1.9e-4). To directly assess the role of uPA and SerpinB2 in PDAC, we employed a 3D organotypic culture system using murine PDACR172H cells, which closely recapitulate the human disease. In this model, exogenous SerpinB2 (but not an inactive SerpinB2 mutant) significantly inhibited the invasion of PDAC (P <0.0001), demonstrating that PDAC invasion is uPA dependent. In a modified 3D organotypic model using wild-type or SerpinB2-/- MEFs to drive matrix contraction, we demonstrate the requirement of SerpinB2 for stromal integrity through collagen remodelling. Further, SerpinB2-/- stromal matrices were 2.3-times more permissive to PDAC cell invasion (P =0.001) and promoted a more amoeboidal mode of migration compared to the wild-type matrices. In an in vivo PDACR172H/MEF co-culture xenograft model, tumours incorporating SerpinB2-/- MEFs were larger and more invasive than wild-type tumours (P =0.0082). In this context we saw significant differences at the invasive front in stromal remodelling, collagen integrity and uPA/uPAR expression with SerpinB2 deletion, consistent with the ex vivo model. This study clearly establishes the importance of uPA in pancreatic cancer progression, revealing novel roles for both tumour and stromal cell specific effects of SerpinB2 on PDAC invasion. In conclusion, these data strongly suggest that the uPA/uPAR axis is a valid therapeutic target in pancreatic cancer.