Abstract 1117: Platelet interaction induces Tissue Factor and a pro-metastatic phenotype in ovarian cancer cells

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Introduction: An increase in circulating platelets, or thrombocytosis, is recognized as an independent risk factor correlated with bad prognosis and metastasis, however the exact role that platelets play in tumor progression has not been fully elucidated. The expression of Tissue Factor (TF) protein by cancer cells has been shown to correlate with Hypercoagulable state and metastasis. It is speculated that cancer cells need to acquire a “Metastasis Initiating Cell (MIC)” phenotype. To achieve this, cells may suffer an Epithelial to Mesenchymal Transition (EMT) coupled with stem-like protein expression in which E-cadherin is lowered, while CD44 and N-cadherin are increased. Ovarian cancer patients develop ascitis, a build up of peritoneal fluid that contains cancerous and serum derived cells. After the surgical removal of the primary and visible tumors, these ascitic borne cells form peritoneal tumors and thus make a good model to study platelet/cancer cells interaction in metastasis. The aim of this work was determine the effect of platelet-cancer cell interaction on TF and EMT marker levels and cancer cell migration in ascites-derived cancer cells. Material and Methods: Ovarian ascitic-isolated cancer cells and cell lines were co-cultivated with human washed platelets (from healthy donors). TF and EMT marker levels were determined by Western blotting. Cancer cell migration was determined by Boyden chambers and the scratch assay. Results: The co-culture of ovarian cancer cells with platelets causes: 1) a phenotypic change in cancer cells, 2) increases TF protein levels and activity, 3) induces EMT markers, 3) promotes chemoattraction and cancer cell migration. Conclusion: We present evidence that platelet-cancer cell interaction promotes a Metastasis Initiating Cell phenotype and enhanced migration. We speculate that platelet-cancer cell interaction may promote the formation of metastatic foci worsening the patient prognosis. Fundings: FONDECYT 1120292, 3120003, 1100870, CORFO 13IDL2-18608, BMRC 13CTI-21526-P6 Citation Format: Renan F. Orellana, Barbara Oliva, Sumie Kato, Loreto Bravo, Pamela Gonzalez, Olga Panes, Diego Mezzano, Mauricio Cuello, Gareth Owen. Platelet interaction induces Tissue Factor and a pro-metastatic phenotype in ovarian cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1117. doi:10.1158/1538-7445.AM2014-1117