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Cathepsin L Induces Proangiogenic Changes in Human Omental Microvascular Endothelial Cells via Activation of the ERK1/2 Pathway

[ Vol. 18 , Issue. ]

Author(s):

Md Zahidul I. Pranjol, Nicholas J. Gutowski, Michael Hannemann and Jacqueline L. Whatmore*Pages 1-12 (12)

Abstract:


Background: Metastasis still remains the major cause of therapeutic failure, poor prognosis and high mortality in epithelial ovarian cancer (EOC) patients. Previously, we showed that EOC cells secrete a range of factors with potential pro-angiogenic activity, in disease-relevant human microvascular omental endothelial cells (HOMECs), including the lysosomal protease cathepsin L (CathL). Thus, the aim of this study was to examine potential pro-proliferative and pro-migratory effects of CathL in HOMECs and the activated signalling pathways, and whether these proangiogenic responses are dependent on CathL-catalytic activity. Methods: HOMECs proliferation was investigated using WST-1, BrdU and CyQUANT assays. Cell migration was examined using a Cultrex Cell 96 transwell migration assay. Enzyme activity was assayed at various pHs using the CathL-specific fluorogenic substrate FY-CHO. Activation of cell signalling pathways was tested using commercially available phosphokinase array and intact cellbased ELISAs. Results: We showed for the first time that CathL has a potent pro-proliferative and pro-migratory effect on HOMECs. For instance, CathL significantly increases HOMEC proliferation (134.8±14.7% vs control 100%) and migration (146.6±17.3% vs control 100%). Our data strongly suggest that these proangiogenic effects of CathL are mediated via a non-proteolytic manner. Finally, we show that CathL-induced activation of the ERK1/2 pathway is involved in inducing these cellular effects in HOMECs. Conclusion: These data suggest that CathL acts as an extracellular ligand and plays an important pro-angiogenic, and thus pro-metastatic, role during EOC metastasis to the omentum, by activating the omental microvasculature, and thus can potentially be targeted therapeutically in the future.

Keywords:

cathepsin L, non-proteolytic, proliferation, migration, angiogenesis

Affiliation:

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon EX1 2LU, Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon EX1 2LU, Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon EX2 7JU, Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon EX1 2LU



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