Poster Presentation Symposium on Proteases and the Tumouri Microenvironment 2017

The kallikrein-related peptidase 4 is involved in activation of prostate-derived stromal cells through the protease-activated receptor-1 (#42)

Thomas Kryza 1 , Lakmalli Silva 1 , Nathalie Bock 1 , Ruth Fuhrman-Luck 1 , Carson Stephens 1 , Mitchel Lawrence 2 , John Hooper 3 , Ying Dong 1 , Gail Risbridger 2 , Judith Clements 1
  1. Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology, Translational Research Institute, Brisbane, Australia, Australian Prostate Cancer Research Centre - Queensland, Woolloongabba, QLD, Australia
  2. Prostate Research Group, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash Partners Comprehensive Cancer Consortium, Monash University, , Clayton, Melbourne, Australia
  3. Cancer Biology and Care Program, Mater Research Institute – The University of Queensland, Translational Research Institute, Brisbane, Australia

Introduction: Kallikrein-related peptidase 4 (KLK4) is over-expressed in prostatic intraepithelial neoplasia (PIN) lesions, highlighting its possible involvement in the initiation steps of prostate cancer. Transcriptomic analysis demonstrates that KLK4 could modulate signalling pathways in prostate-derived stromal cells, notably, PAR1-associated signalling. We hypothesize that KLK4 could be involved in activation of stromal cells surrounding prostate epithelium through activating PAR1.

Method: PAR1 expression in prostate-derived cell lines was assessed, and KLK4-mediated activation of PAR1 in stromal cells confirmed. WPMY1 cells, primary prostate fibroblasts (NPFs) and primary cancer associated fibroblasts (CAFs) were treated with KLK4 and qRT-PCR performed for PAR1-regulated genes known to be involved in stromal cell activation; PAR1-specific siRNA and a PAR1 inhibitor served as negative controls. KLK4-mediated regulation of selected targets was confirmed at the protein level. The effect of KLK4 on WPMY1 cell proliferation and production of the fibroblast activation marker, alpha-SMA, was assessed. Finally, the secretome of stromal cells treated with KLK4 was analysed using a protein array and its pro-angiogenic activity was evaluated by the tubulogenesis assay.

Results: WPMY1 cell-produced PAR1 was activated by KLK4, inducing an intracellular calcium-flux and modulating the production of factors (FGF1, TAGLN) associated with fibroblast activation at both the gene and protein level as in NPFs and CAFs. This deregulation was inhibited by a PAR1-specific inhibitor or siRNA. As with a PAR1-activating peptide, KLK4 increased WPMY1 cell proliferation and expression of the fibroblast activation marker, alpha-SMA. Moreover, KLK4 treatment modulates the WPMY1 secretome inducing an upregulation of different growth factors and cytokines playing key roles during prostate cancer progression.

Conclusion: As KLK4 is over-expressed in PIN lesions, which can precede, or be associated with, prostate cancer, and as it can activate prostate-derived fibroblasts, a required step for prostate cancer initiation, attenuating KLK4 activity in non-cancerous prostate lesions may limit prostate cancer initiation.