Cathepsin D expression in pancreatic ductal adenocarcinoma (PDAC) cells increases proliferation and reduces survival of pancreatic cancer patients

U Mahajan; E Langhoff; E Costello; W Greenhalf; C Halloran; T Schwaiger; G Beyer; F Weiss; J Neoptolemos; T Kohlmann; M Maron; M Büchler; M Lerch; J Mayerle

doi:10.1055/s-0035-1559095

Zeitschrift für Gastroenterologie, Inhaltsverzeichnis

Cathepsin D expression in pancreatic ductal adenocarcinoma (PDAC) cells increases proliferation and reduces survival of pancreatic cancer patients

U Mahajan ¹, E Langhoff ¹, E Costello ², W Greenhalf ³, C Halloran ², T Schwaiger ¹, G Beyer ¹, F Weiss ¹, J Neoptolemos ², T Kohlmann ⁴, M Maron ⁴, M Büchler ⁵, M Lerch ¹, J Mayerle ¹

¹Ernst-Moritz-Arndt-Universität, Universitätsmedizin Greifswald, Klinik für Innere Medizin A, Greifswald, Deutschland
²University of Liverpool, NIHR Liverpool Pancreas Biomedical Research Centre, Liverpool, Vereinigtes Königreich
³University of Liverpool, 2NIHR Liverpool Pancreas Biomedical Research Centre, Liverpool, Vereinigtes Königreich
⁴Ernst-Moritz-Arndt-Universität, Universitätsmedizin Greifswald, Institut für Community Medicine, Greifswald, Deutschland
⁵University of Heidelberg, Department of General, Visceral and Transplantation Surgery, Heidelberg, Deutschland

Abstract

Background: Remodelling of the pancreatic cancer tumour microenvironment and extracellular matrix (ECM) has been implicated in the prognosis of PDAC. We investigated whether the aspartic protease cathepsin-D contributes to proliferation, migration and fibrogenesis of pancreatic cancer and whether its expression affects the survival of pancreatic cancer patients.

Material & Methods: Murine PSC and pancreatic cancer PD6606-cells were used for WB and IF. Cathepsin-D activity was inhibited with pepstatin and its expression silenced with siRNA. TGFβ1 was measured by ELISA and proliferation by MTT assay. Tumour tissue microarrays of 404 patients from the ESPAC-3 trial were stained with anti-cathepsin-D antibody and patients with the highest quartile H-score (cut-off 22.35) were compared with those in the lowest quartile using Kaplan-Meier analysis, log-rank-tests, and Cox-proportional-hazards models. All statistical tests were two-sided.

Results: Inhibition of cathepsin-D in PDAC resulted in significantly reduced proliferation and migration. Cathepsin-D expression increased in parallel with PSC trans-differentiation to myofibroblasts. Silencing or inhibition of cathepsin-D decreased PSC proliferation by 20 – 30%. There was a time-dependent activation of latent TGFβ1 and cathepsin-D cleaved latent TGFβ1, leading to activation. Inhibition of cathepsin-D decreased activated TGFβ1. In 1824 tissue-microarray-cores patients median overall patients' survival was 23.85 months (95% CI 21.0 – 26.2). Median survival for patients in the highest quartile cathepsin-D H-score was 21.2 months (95% CI 17.3 – 24.8) and in the lowest quartile 27.2 months (95% CI 24.1 – 31.2) c2LR,1DF = 4.33; P = 0.0374.

Discussion: In pancreatic cancer cathepsin-D expression not only regulates fibrogenesis and stromal development but also cancer cell proliferation and migration. These mechanisms make cathepsin-D a driver of pancreatic cancer growth and contribute to for the poor prognosis of patients with pancreatic cancer.