Oral Presentation Symposium on Proteases and the Tumouri Microenvironment 2017

A multi-omics approach to determining the roles of the kallikrein-related peptidases in the tumour microenvironment (#27)

R. Fuhrman-Luck 1 2 , L. Silva 2 , T. Kryza 1 2 , M. Hastie 3 , B. Ho 4 , T. Stoll 3 , C. Stephens 1 2 , A. Rockstroh 1 , M. Lehman 1 , Y. Dong 2 , D. Loessner 2 , D. Hutmacher 2 , M. Lawrence 5 , G. Risbridger 5 , C. Nelson 1 , O. Kleifeld 6 , J. Gorman 3 , Judith Clements 1 2
  1. Australian Prostate Cancer Research Centre – Queensland, Princess Alexandra Hospital, Translational Research Institute, Brisbane, QLD
  2. Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
  3. Protein Discovery Centre, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
  4. Monash Bioinformatics Platform, Monash University, Clayton, VIC, Australia
  5. Prostate Cancer Research Program, Monash University, Clayton, VIC, Australia
  6. Monash Biomedical Proteomic Facility, Monash University, Clayton, VIC, Australia

The kallikrein-related (KLK) serine peptidases are over-expressed in prostate and ovarian cancer where they have been associated with progression and poor outcomes, hence, their potential as prognostic biomarkers and therapeutic targets. They are suggested to play a role in remodelling the tumour microenvironment through their proteolytic action but the precise substrates and underlying mechanistic pathways are largely unknown.  In the localised prostate cancer microenvironment, we used an unbiased whole proteome approach, PROTOMAP, and identified 36 and 60 putative novel KLK4 protein substrates derived from prostate cancer and stromal cells, respectively, 11 of which directly interact with the growth factor, TGFβ1.  Strikingly, the most enriched pathway (based on DAVID analysis, p<0.01) following transcriptome analysis of the KLK4-treated cells was the TGFβ1 pathway, followed by the thrombin receptor/PAR-1 pathway. In the ovarian cancer microenvironment, 18 putative novel KLK7 substrates were identified by both the TAILS and PROTOMAP platforms in a high grade serous ovarian cancer (HGSOC) cell secretome, all of which are involved in matrix degrading processes required for peritoneal invasion and metastasis. KLK7-treated HGSOC cell lines expressed elevated transcripts of several genes that modulate inflammation and angiogenesis, such as VEGF-A. KLK7 and KLK4 selective active site inhibitors based on the sunflower trypsin inhibitor backbone confirmed their catalytic involvement in these processes. These data suggest that KLK7, either directly or indirectly via the above cleaved substrates, in HGSOC cells mediates peritoneal metastasis and potentially angiogenesis, by modulating inflammatory reaction pathways. In addition, these findings suggest that KLK4 is a critical regulator of the reactive stromal niche, via the TGFβ1 and PAR-1 pathways, and a potential novel therapeutic target for prostate cancer.