Poster with mini oral Clinical Oncology Society of Australia 2014 Annual Scientific Meeting

Targeting the RON/MST1R receptor using LCRF004, may provide an effective novel interventional strategy in malignant pleural mesothelioma (#206)

Anne-Marie Baird 1 2 , Kenneth O'Byrne 1 2 3 , David Easty 2 , Liam Shiels 4 , Annette Byrne 4 , Stéphane Raeppel 5 , Alex Soltermann 6 , Daisuke Nonaka 7 , Dean Fennell 8 , Luciano Mutti 9 , Harvey Pass 10 , Isabelle Opitz 6 , Steven Gray 2
  1. Cancer and Ageing Research Program, Queensland University of Technology, Brisbane, QLD, Australia
  2. Thoracic Oncology Research Group, St. James's Hospital, Trinity College Dublin, Dublin, Ireland
  3. Divison of Cancer Services , Princess Alexandra Hospital, Brisbane, QLD, Australia
  4. Royal College of Surgeons in Ireland, Dublin, Ireland
  5. ChemRF, Montreal, QC, Canada
  6. Zurich University, Zurich, Switzerland
  7. The Christie NHS Foundation Trust, Manchester, UK
  8. University of Leicester & Leicester University Hospitals, Leicester, UK
  9. Vercelli Hospital, Vercelli, Italy
  10. NYU School of Medicine, New York, USA

Aims

Malignant pleural mesothelioma (MPM) is an aggressive inflammatory cancer. Using a phospho-receptor tyrosine kinase array, we identified RON as frequently activated in MPM patient samples and cell lines. RON is a member of the MET proto-oncogene family and is bound by macrophage stimulating protein (MSP). The aim of this study was to examine the MSP-RON signalling axis in MPM.

Methods

Immunohistochemistry was performed for RON, MSP and CD68 on a MPM tissue-microarray (n=132). MSP levels were determined in MPM and control serum samples (n=40). Expression levels were correlated with clinico-pathological data. MPM cell lines and a normal mesothelial cell line were screened for the expression of RON and MSP at the protein (Western) and mRNA (RT-PCR) level. Downstream mediators affected by MSP stimulation were identified using a proteome profiler array. The effect of MSP, IMC-RON8 (humanised IgG1 monoclonal antibody), LCRF004 (small molecule inhibitor) and NRWHE (small peptide) was examined using proliferation (BrdU ELISA), viability and migration (xCELLigence) assays. An xenograft study was completed with LCRF004.

Results

High positivity for total RON by IHC was an independent predictor of favourable prognosis. Additionally, elevated expression levels of MSP correlated with better survival. The protein and mRNA levels of RON and MSP were differentially expressed in MPM cell lines. MSP treatment resulted in the phosphorylation of a number of kinases including Src. Treatment with LCRF004 resulted in a significant decrease in proliferation, viability, migration and reduced tumour growth in vivo (p<0.05, compared with vehicle control).

Conclusion

The seemingly counter intuitive results obtained from TMA studies and cell line data, may be dependant on RON isoform expression. Nevertheless, the in vivo and in vitro data generated in this study, indicates that the MSP-RON signalling axis is a potential target in MPM. LCRF004 is an encouraging novel targeted therapeutic agent in this disease.